Dissertations / Theses on the topic 'Microstrip filter designs'

This thesis is a study of tunability of edge-coupled filters. Microstrip edge-coupled bandpass filters are planar structures and have advantages such as easy design procedures and simple integration into circuits. Three tuning techniques were implemented. The first technique involved the loading of one open end of each coupled into tunable capacitors. The second technique used a tunable resonator in series with the edge-coupled blocks. The final design made use of tunable feedback sections. A detailed mathematical analysis of each design was performed. MATLAB code based on the analyses was written. The MATLAB simulations were compared to Agilent Advanced Design System (ADS) simulations in order to and the minimum design parameters required to arrive at an approximate solution. ADS simulations were used to accurately determine the final design. The tunable filters with a series capacitor and feedback were fabricated on RO4003C boards from Roger's Corporation, having a dielectric constant of 3.55. The built boards were then tested with the HP 8510c network analyzer. The measured results were compared to the ADS simulations. The filter with a tuning capacitor in series with the coupled sections had high insertion loss of -20 dB and tuning range in terms of KHz. The design involving feedback had advantages over the previous design since the insertion loss was better than -14 dB and it had a tuning range of 91 MHz. It was observed from simulations that the design had an adjustable tunability range and bandwidth as the width was varied.

This thesis presents Design, Measurement and analysis for size reduction of the Coupled line micro strip Hairpin band pass filters (MHBPF’s). Hairpin filters are an interesting topic for microwave designers. These planar circuits are widely used in wireless transceivers and other microwave projects due to an easy design process. The filter design and analysis described in this paper can be used for wireless transceivers as well as for microwave links. Two techniques have been employed for the size reduction and four different filters have been designed. 1st Technique, Conventional Hairpin configuration uses folding of the normal λ/2 resonators into U shape. 2nd technique exploits the cross coupling of the resonators for further size reduction of the filters.  From 1st to last design, different properties of micro strip and couple lines have been analyzed, observed, and finally exploited to reach to a more compact solution. Agilent ADS have been used for the simulation process of the initial filters. Further on, AWR Microwave office has been used for the EM simulation part of the project and a detailed analysis for the size reduction with respect to the different properties of the materials used. Since insertion loss method is going to be used for the designs, low pass filter prototypes parameters are used for further conversion to band pass. The loaded Q factor and the mix coupling coefficients between resonators have been calculated from standard empirical equations. FR4 substrate is used for manufacturing process. RogersRO3210 has also been used as a substrate for 3-section design in AWR Microwave Office for the illustration of size reduction with respect to substrate properties. The design with FR4 substrate has been manufactured and tested. The results have been analyzed on Vector Network Analyzer and displayed in results sections.

Many of todays' sophisticated communication systems, particularly those operating in the microwave frequency range, have a growing demand for highly selective and frequency agile filters with fast tuning rates. At microwave frequencies above 2GHz, filters that combine both tuning speed and high selectivity are difficult to realise. Unloaded Q values in the range of 1000 are required for reasonable selectivity. At present, these requirements with the exception of tuning speed are mainly fulfilled by electronically tuned filters employing yttrium iron garnet (YIG) resonators. An alternative solution to this problem is to utilise high-Q dielectric resonators (DRs) in-conjunction with an appropriate tuning mechanism to realise tunable filters. DRs can provide unloaded Q-factors comparable to waveguide resonators (typically 10,000 @ 10GHz), but at a substantially lower weight and smaller volume. DRs are also compatible with a microstrip environment which eliminates the need for microstrip to waveguide adaptors. This thesis is devoted to the study of the design and realisation of electronically tuned microwave filters employing dielectric resonators. Knowledge of the values of the coupling coefficient between a pair of DRs is essential for the design of both the bandpass and bandstop filters using these resonators. This necessitates the use of an accurate expression for the coupling coefficient which was derived by performing an electromagnetic analysis on the DR structure. This analysis also took into account the effects of the actual circuit environment such as the resonator support spacer and the dimensions of the enclosure. The experimental data presented shows very good agreement with the computed data. Novel techniques for the tuning of the DR operating in its fundamental mode are presented. These tuning configurations incorporating GaAs varactor diodes have been investigated to determine a circuit which greatly perturbs the DR fundamental mode. The amount of tuning that can be obtained by these methods exceeds more than 60MHz of the unperturbed value of resonant frequency with acceptable amount of Q-factor degradation. These tuning characteristics are superior to similar devices reported to date. A simple analytical expression is also derived for determining the tuning range of such a structure. Techniques for the design of novel electronically tunable DR bandpass and bandstop filters having either a Chebyshev or Butterworth response are presented. Design for prescribed response, starting from a low-pass lumped-element prototype filter is outlined. The bandpass filter structure consists of cascaded resonators, with the end resonators coupled to microstrip arcs on a substrate, whereas, the bandstop filter consists of a microstrip line with resonators mounted at intervals of one-quarter-wavelength. Tuning is achieved by varying a bias voltage to the varactor. The measured performances of several practical devices operating in the S-band are presented, these agree closely with theory. The centre frequency of these filters is within 2.46% and the bandwidth is within 3.75% of the desired values.

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California
In the past, airplanes, target drones, pods, and large missiles have been instrumented with telemetry, flight termination and beacon tracking antennas to assess performance. With the emerging use of the Global Positioning System (GPS) for tracking purposes, GPS is also included as part of the instrumentation package. This paper addresses the design of a conformal wraparound antenna system to cover the telemetry and GPS L1 frequencies for a small (2.75 inch) diameter airborne projectile. A filter is also integrated into the antenna system to isolate the transmitted telemetry signal from the received GPS signal. This integration is necessary due to the lack of space in the small diameter projectile. Performance characteristics of the prototype antenna system are also presented.

Yes
This study presents an original asymmetric stepped-impedance resonator filter combined with meander coupled-line structures and enabling the realisation of finite transmission zeros (TZs) and the implementation of multi-band bandpass filters. The meander coupled sections (MCSs) tune the TZs and resonant frequencies: with higher-order spurious frequencies cancelled by the TZs, a single wideband with wide stopband from 1.18 to 1.84 GHz is possible. Furthermore, by positioning the finite TZs between the high-order spurious frequencies and adjusting the coupling strength between resonators, a quint-wideband filter can be realised, with centre frequencies of 1.19, 4.29, 5.43, 6.97, 9.9 GHz and fractional bandwidths of 31.9, 15.4, 15.8, 4.3, 39.2%, respectively. More importantly, two filters with single/quad-wideband performance can be realised by tuning the parameters of the MCS, and therefore they can be designed separately by using only one original structure. The triple-wideband filter is realised with the help of the asymmetric parallel uncoupled microstrip section. These filter structures enjoy the advantage of single/multi-band versatility, structure reusability and simplicity. The good in-band and out-of-band performance, low loss and simple structure of the proposed single/tri/quint-wideband filters make them very promising for applications in future multi-standard wireless communication.
European Union's Horizon 2020 research and innovation programme under Grant agreement H2020-MSCA-ITN-2016 SECRET-722424.

In this report the analysis of microstrip electrodynamic structures on basis of high-temperature superconductors is carried out and a mathematical model of microstrip devices with lumped and distributed nonlinear properties is created. For this purpose nonlinear integral equations method and method of moments are used. In the issue of the work a SHF filter based on the equivalent circuit of elements with lumped parameters is also studied. It is ascertained that the received mathematical model allows to achieve more proper results of modeling on compensation of variation of current-density distribution nearby the edges of conductor break.

This dissertation proposes three novel bandpass filter structures to protect systems exposed to damaging levels of electromagnetic (EM) radiation from intentional and unintentional high-power microwave (HPM) sources. This is of interest because many commercial microwave communications and sensor systems are unprotected from high power levels. Novel technologies to harden front-end components must maintain existing system performance and cost. The proposed concepts all use low-cost printed circuit board (PCB) fabrication to create compact solutions that support high integration.

The first proposed filter achieves size reduction of 46% using a technology that is suitable for low-loss, narrowband filters that can handle high power levels. This is accomplished by reducing a substrate-integrated waveguide (SIW) loaded evanescent-mode bandpass filter to a half-mode SIW (HMSIW) structure. Demonstrated third-order SIW and HMSIW filters have 1.7 GHz center frequency and 0.2 GHz bandwidth. Simulation and measurements of the filters utilizing combline resonators prove the underlying principles.

The second proposed device combines a traditional microstrip bent hairpin filter with encapsulated gas plasma elements to create a filter-limiter: a novel narrowband filter with integral HPM limiter behavior. An equivalent circuit model is presented for the ac coupled plasma-shell components used in this dissertation, and parameter values were extracted from measured results and EM simulation. The theory of operation of the proposed filter-limiter was experimentally validated and key predictions were demonstrated including two modes of operation in the on state: a constant output power mode and constant attenuation mode at high power. A third-order filter-limiter with center frequency of 870 MHz was demonstrated. It operates passively from incident microwave energy, and can be primed with an external voltage source to reduce both limiter turn-on threshold power and output power variation during limiting. Limiter functionality has minimal impact on filter size, weight, performance, and cost.

The third proposed device demonstrates a large-area, light-weight plasma device that interacts with propagating X-band (8-12 GHz) microwave energy. The structure acts as a switchable EM aperture that can be integrated into a radome structure that shields enclosed antenna(s) from incident energy. Active elements are plasma-shells that are electrically excited by frequency selective surfaces (FSS) that are transparent to the frequency band of interest. The result is equivalent to large-area free-space plasma confined in a discrete layer. A novel structure was designed with the aid of full-wave simulation and was fabricated as a 76.2 mm square array. Transmission performance was tested across different drive voltages and incidence angles. Switchable attenuation of 7 dB was measured across the passband when driven with 1400 V_pp at 1 MHz. Plasma electron density was estimated to be 3.6 × 10 ¹² cm^-3 from theory and full-wave simulation. The proposed structure has potential for use on mobile platforms.

This thesis tackles issues of particular interest regarding analysis and design of passive components at the mm-wave and Terahertz (THz) bands. Innovative analysis techniques and modeling of complex structures, design procedures, and practical implementation of advanced passive devices are presented. The first part of the thesis is dedicated to THz passive components. These days, THz technology suffers from the lack of suitable waveguiding structures since both, metals and dielectric, are lossy at THz frequencies. This implies that neither conventional closed metallic structures used at microwave frequencies, nor dielectric waveguides used in the optical regime, are adequate solutions. Among a variety of new proposals, the Single Wire Waveguide (SWW) stands out due to its low attenuation and dispersion. However, this surface waveguide presents difficult excitation and strong radiation on bends. A Dielectric-Coated Single Wire Waveguide (DCSWW) can be used to alleviate these problems, but advantages of the SWW are lost and new problems arise. Until now, literature has not given proper solution to radiation on bends and, on the other hand, rigorous characterization of these waveguides lacks these days. This thesis provides, for the first time, a complete modal analysis of both waveguides, appropriated for THz frequencies. This analysis is later applied to solve the problem of radiation on bends. Several structures and design procedures to alleviate radiation losses are presented and experimentally validated. The second part of the thesis is dedicated to mm-wave passive components. These days, when implementing passive components to operate at such small, millimetric wavelengths, to ensure proper metallic contact and alignment between parts results challenging. In addition, dielectric absorption becomes significant at mm-wave frequencies. Consequently, conventional hollow metallic waveguides and planar transmission lines present high attenuation so that new topologies are being considered. Gap Waveguides (GWs), based on a periodic structure introducing an Electromagnetic Bandgap effect, result very suitable since they do not require metallic contacts and avoid dielectric losses. However, although GWs have great potential, several issues prevent GW technology from becoming consolidated and universally used. On the one hand, the topological complexity of GWs difficulties the design process since full-wave simulations are time-costly and there is a lack of appropriate analysis methods and suitable synthesis procedures. On the other hand, benefits of using GWs instead of conventional structures are required to be more clearly evidenced with high-performance GW components and proper comparatives with conventional structures. This thesis introduces several efficient analysis methods, models, and synthesis techniques that will allow engineers without significant background in GWs to straightforwardly implement GW devices. In addition, several high-performance narrow-band filters operating at Ka-band and V-band, as well as a rigorous comparative with rectangular waveguide topology, are presented.
Esta tesis aborda problemas actuales en el análisis y diseño de componentes pasivos en las bandas de onda milimétrica y Terahercios (THz). Se presentan nuevas técnicas de análisis y modelado de estructuras complejas, procedimientos de diseño, e implementación práctica de dispositivos pasivos avanzados. La primera parte de la tesis se dedica a componentes pasivos de THz. Actualmente no se disponen de guías de onda adecuadas a THz debido a que ambos, metales y dieléctricos, introducen grandes pérdidas. En consecuencia, no es adecuado escalar las estructuras metálicas cerradas usadas en microondas, ni las guías dieléctricas usadas a frecuencias ópticas. Entre un gran número de recientes propuestas, la Single Wire Waveguide (SWW) destaca por su baja atenuación y casi nula dispersión. No obstante, como guía superficial, la SWW presenta difícil excitación y radiación en curvas. El uso de un recubrimiento dieléctrico, creando la Dielecric-Coated Single Wire Waveguide (DCSWW), alivia estos inconvenientes, pero las ventajas anteriores se pierden y nuevos problemas aparecen. Hasta la fecha, no se han encontrado soluciones adecuadas para la radiación en curvas de la SWW. Además, se echa en falta una caracterización rigurosa de ambas guías. Esta tesis presenta, por primera vez, un análisis modal completo de SWW y DCSWW, adecuado a la banda de THz. Este análisis es aplicado posteriormente para evitar el problema de la radiación en curvas. Se presentan y validan experimentalmente diversas estructuras y procedimientos de diseño. La segunda parte de la tesis abarca componentes pasivos de ondas milimétricas. Actualmente, estos componentes sufren una importante degradación de su respuesta debido a que resulta difícil asegurar contacto metálico y alineamiento adecuados para la operación a longitudes de onda tan pequeñas. Además, la absorción dieléctrica incrementa notablemente a estas frecuencias. En consecuencia, tanto guías metálicas huecas como líneas de transmisión planares convencionales presentan gran atenuación, siendo necesario considerar topologías alternativas. Las Gap Waveguides (GWs), basadas en una estructura periódica que introduce un efecto de Electromagnetic Bandgap, resultan muy adecuadas puesto que no requieren contacto entre partes metálicas y evitan las pérdidas en dieléctricos. No obstante, a pesar del potencial de las GWs, varias barreras impiden la consolidación y uso universal de esta tecnología. Por una parte, la compleja topología de las GWs dificulta el proceso de diseño dado que las simulaciones de onda completa consumen mucho tiempo y no existen actualmente métodos de análisis y diseño apropiados. Por otra parte, es necesario evidenciar el beneficio de usar GWs mediante dispositivos GW de altas prestaciones y comparativas adecuadas con estructuras convencionales. Esta tesis presenta diversos métodos de análisis eficientes, modelos, y técnicas de diseño que permitirán la síntesis de dispositivos GW sin necesidad de un conocimiento profundo de esta tecnología. Asimismo, se presentan varios filtros de banda estrecha operando en las bandas Ka y V con altas prestaciones, así como una comparativa rigurosa con la guía rectangular.
Aquesta tesi aborda problemes actuals en relació a l'anàlisi i disseny de components passius en les bandes d'ona mil·limètrica i Terahercis. Es presenten noves tècniques d'anàlisi i modelatge d'estructures complexes, procediments de disseny, i implementació pràctica de dispositius passius avançats. La primera part de la tesi es focalitza en components passius de THz. Actualment no es disposen de guies d'ona adequades a THz causa que tots dos, metalls i dielèctrics, introdueixen grans pèrdues. En conseqüència, no és adequat escalar les estructures metál·liques tancades usades en microones, ni les guies dielèctriques usades a freqüències òptiques. Entre un gran nombre de propostes recents, la Single Wire Waveguide (SWW) destaca per la seua baixa atenuació i quasi nul·la dispersió. No obstant això, com a guia superficial, la SWW presenta difícil excitació i radiació en corbes. L'ús d'un recobriment dielèctric, creant la Dielecric-Coated Single Wire Waveguide (DCSWW), alleuja aquests inconvenients, però els avantatges anteriors es perden i nous problemes apareixen. Fins a la data, no s'han trobat solucions adequades per a la radiació en corbes de la SWW. A més, es troba a faltar una caracterització rigorosa d'ambdues guies. Aquesta tesi presenta, per primera vegada, un anàlisi modal complet de SWW i DCSWW, adequat a la banda de THz. Aquest anàlisi és aplicat posteriorment per evitar el problema de la radiació en corbes. Es presenten i validen experimentalment diverses estructures i procediments de disseny. La segona part de la tesi es centra en components passius d'ones mil·limètriques. Actualment, aquests components pateixen una important degradació de la seua resposta a causa de que resulta difícil assegurar contacte metàl·lic i alineament adequats per a l'operació a longituds d'ona tan menudes. A més, l'absorció dielèctrica incrementa notablement a aquestes freqüències. En conseqüència, tant guies metàl·liques buides com línies de transmissió planars convencionals presenten gran atenuació, sent necessari considerar topologies alternatives. Les Gap Waveguides (GWs), basades en una estructura periòdica que introdueix un efecte de Electromagnetic Bandgap, resulten molt adequades ja que no requereixen contacte entre parts metàl·liques i eviten les pèrdues en dielèctrics. No obstant, tot i el potencial de les GWs, diverses barreres impedixen la consolidació i ús universal d'aquesta tecnologia. D'una banda, la complexa topologia de les GWs dificulta el procés de disseny atés que les simulacions d'ona completa consumeixen molt de temps i no existeixen actualment mètodes d'anàlisi i disseny apropiats. D'altra banda, és necessari evidenciar el benefici d'utilitzar GWs mitjançant dispositius GW d'altes prestacions i comparatives adequades amb estructures convencionals. Aquesta tesi presenta diversos mètodes d'anàlisi eficients, models, i tècniques de disseny que permetran la síntesi de dispositius GW sense necessitat d'un coneixement profund d'aquesta tecnologia. Així mateix, es presenten diversos filtres de banda estreta operant en les bandes Ka i V amb altes prestacions, així com una comparativa rigorosa amb la guia rectangular.
Berenguer Verdú, AJ. (2017). Analysis and design of efficient passive components for the millimeter-wave and THz bands [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/84004
TESIS

La technologie MID (Molded Interconnect Device), fait de leur performance électrique, la flexibilitédans les circuits RF, le potentiel de réduire le nombre de composants, les étapes du processus et laminiaturisation du produit final, a conduit à de nouvelles contraintes à la RF (Radio Frequency) et ledomaine des micro-ondes. Composants moulés sont interconnectées avec des substratsthermoplastiques et les pistes conductrices sont injectés sur la surface. L'objectif de cette thèse estd'étudier la compatibilité de MID pour les applications RF. Les avantages de la technologie MID dansle domaine RF est exploitée pour les lignes de transmission, filtres passifs, coupleurs directionnels etantennes réalisation. La caractérisation RF de différents matériaux de substrat MID et l'étude de laperformance des composants RF ci-dessus sur la base de différentes technologies de fabrication MIDsont inclus dans la thèse. Enfin, le concept d'une étude d'amélioration de la permittivité de certainsthermoplastiques sont également étudiés
MID (Molded Interconnect Devices) technology, owing to their electrical performance,flexibility in RF circuits, its potential to reduce the number of components, process steps andminiaturization of the final product, has led to some new constraints to the RF (RadioFrequency) and microwave domain. Molded components are interconnected withthermoplastic substrates and conductive traces are injected on the surface. The objective ofthis thesis is to study the compatibility of MIDs for RF applications. The advantages of MIDtechnology in the RF domain is exploited for transmission lines, passive filters, directionalcouplers and planar and 3D antennas realization. The RF characterization of various MIDsubstrate materials and the study of the performance of the above RF components based onvarious MID fabrication technologies are included in the thesis. Finally, an permittivityimprovement study of some thermoplastics are also studied

碩士
國立彰化師範大學
電信工程研究所
98
In this thesis, the study of planar structure filter designs which include the wide stopband band-pass filter, diplexer, and wide bandwidth band-pass filter. Firstly, the filter, possesses the wide stopband performance is presented. Thus, the filters is composed of CPW（coplanar waveguide）and the microstrip line. The insertion loss of pass-band was very good. In the design of diplexer, the mechanism of transmission zeros implantation is employed to improve the isolation between I/O ports. In the wide stopband band-pass filter design, a band-pass filter (BPF) using forked stepped-impedance resonators (SIRs) was proposed with having a very wide stopband performance. The circuit composed of two forked SIRs connected with a narrow microstrip with the latter’s middle point shorting to the ground through a via hole. The FSIRs filter operated in a quarter-wavelength resonance condition. The filter was built for WLAN IEEE 802.11b/g (2.4/2.45 GHz) applications. A long narrow coupled microstrip which increasing the stopband range was used to couple I/O signal to/from the resonators. The upper stopband, its frequency range was measured from 2.76 to 23.08 GHz with the criterion of the signal rejection levels greater than 20 dB. The stopband’s upper-end is over 9.5 f0 with the central frequency of 2.44 GHz. In the design of diplexer, we propose a novel design of a UMTS diplexer using a coupled microstrip line in conjunction with the stepped-impedance resonator. The diplexer is composed of two band-pass filters, which termed as the Tx- and Rx-filter. The feature is designed to transmit-band (Tx-band) and receive-band (Rx-band) both implantation in the low and high end of the band limit having adjustable transmission zeros. Transmission zero has been implanted in each filter design for increasing the isolation between the Rx- and Tx-port. In addition, the coupled line with the addition of spur-line can produce an extra transmission zero. The superposition of the extra zero and the original one further enhances the isolation effect. The measured isolations are greater than 30 dB in Tx-band and Rx-band. The measured central frequency is 1.94 GHz in Tx-band. Its 3-dB bandwidth is 100 MHz which encounters the range from 1.88 GHz to 1.98 GHz. Measured transmission zeros are at 1.52 GHz and 2.12 GHz. The Rx-band measured central frequency is 2.12 GHz. The 3-dB bandwidth is 130 MHz which covers the frequency range from 2.06 GHz to 2.19 GHz. The measured transmission zeros are at 1.94 GHz and 2.41 GHz. In the design of wide bandwidth band-pass filter, an asymmetrically cross-shaped multi-mode resonator fed by the CPW has implemented in the wide bandwidth band-pass filter design. The pass-band exhibits very low insertion loss. The broadside-coupling of the CPW and the resonator provides a strong capacitive coupling which enhances the wide bandwidth performance. The measured 3-dB bandwidth is 2.37 GHz. The pass-band range covers from 2.13 GHz to 4.5 GHz. The measured upper stop-band bandwidth is 2.38 GHz with the criterion of the signal rejection levels greater than 20 dB. Two transmission zeros are implanted on both sides of the pass-band to enhance the signal selectivity. In this thesis, the designs of the proposed filters should be able to apply to wireless microwave circuit design.

This dissertation mainly discuses various microstrip bandpass filter (BPF) designs. The filter designs include: a coupled line BPF using nonuniform arbitrary image impedances, miniaturized BPF utilizing dumbbell shaped slot resonator (DSSR), BPF employing isosceles triangle shaped patch resonator (ITSPR), BPF with a complimentary split ring resonator (CSRR) and triple-band BPF (TBBPF). In the coupled line BPF designs, a capacitive gap-coupled BPF and parallel coupled line BPF are introduced, where two different arbitrary image impedances are applied for the designs. Based on the proposed equivalent circuit model, the coupled BPF's design equations are derived, and they are validated from comparisons of the calculated and simulated results. For a miniaturized BPF, the DSSR is utilized in the filter design. An equivalent circuit model of the DSSR is also presented and validated through simulations and measurements. The ITSPR is introduced for simple BPF and diplexer designs. The ITSPR's design equations, effective dielectric constant, and fractional bandwidth are discussed, and their validities are demonstrated from electromagnetic (EM) simulations and measurements. The coupled type complementary split ring resonator (CSRR) is introduced for a compact direct-coupled BPF. The proposed unit cell of the resonator consists of two CSRRs, where gaps of outside rings face each other to achieve a strong cross coupling. For an analysis of the coupled CSRR, an equivalent circuit model is discussed and validated through circuit and EM simulations. Based on the coupled CSRR structure, two-/four- pole direct-coupled BPFs are designed, simulated, and measured. The TBBPF design using admittance inverters are presented. In the TBBPF design, the center frequencies and fractional bandwidths (FBW) of each passband can be adjustable. Low cost phased array systems operating from 8 to 12 GHz are introduced. A phased array using a piezoelectric transducer (PET) phase shifter is designed and tested. Compared to the phased array using the PET phase shifter, another phased array utilizing 4-bit monolithic microwave integrated circuit (MMIC) phase shifters is demonstrated. Both phased array systems are simple and easy to fabricate.

碩士
國立彰化師範大學
電信工程研究所
96
Abstract In this thesis, multi-band microwave bandpass filters (BPFs) designed using cross-coupled stepped-impedance resonators (SIRs) were studied. Three microwave filters,including two dual-band and one single-band BPFs were designed, implemented, andinvestigated. The first dual-band BPF circuit consists of λ/2 and λ/4 stepped impedance resonators (SIRs) for the WLAN applications. The filter covers both the operating frequencies of 2.45 GHz and 5.2-5.8 GHz. The doubly parallel-coupling mechanism is used in the filter design to reduce the insertion losses and to gain a wider bandwidth (BW). The cross coupling configuration and the tapped-line I/O feed are adopted in this filter design to provide the attenuation poles for improving the signal selectivity and stopband rejection levels. Experiments were conducted to verify the circuit performance. The second BPF proposed in this thesis was a dual-band bandpass filter using λ/4 stepped impedance resonators (SIRs) embedded with spur-line for the WLAN applications. The filter covers both the operating frequencies of 2.45 GHz and 5.2-5.8 GHz . The crossly coupled mechanism is used in the filter design to provide attenuation poles by the passband edges for enhancing the signal selectivity and to increase stopband rejection levels. The tapped-line is incorporated in feed structure to save the circuit space. The spur-line is embedded in each I/O SIRs to push the upper stopband limit to a higher frequency. Experiments are conducted to verify the circuit performance. A good agreement is observed between the simulation and the measurement. Finally, we employ the stepped-width-slots spur-line (SWSS) in the parallel-coupled microstrip BPF to eliminate the higher harmonics due to coupled-lines’ even- and odd-mode effect. The ABCD matrix of the SWSS based on the even- and odd-mode of parallel-coupled line model is developed to analyze the structure frequency response. Single SWSS or two SWSSs are embedded in each of the coupled-lines to suppress signals of multiple frequencies for extending stopband region. Results obtained in this research can be applied to commercially practical RF and microwave systems. The techniques presented in this research are expected to serve as a useful reference for microwave filter designers in this and related research fields.

碩士
義守大學
電機工程學系碩士班
94
The purpose of this thesis is to design bandgap filter by adopting the idea of microstripline and photonic bandgap. The one-dimension bandstop filter is mainly structured by the periodical changes of microstripline and planned from the models of step, triangle and sinusoidal. The software will be utilized to simulate different types and different pairs as the basis to observe the frequency response of one-dimension bandstop filter and as a comparison with the experiment. The bandstop filter with one-dimension triangle and one-dimension sinusoidal causes suppression of harmonic. Furthermore, in order to complete a coplanar two-dimension bandstop filter, this plan will reply on combination of divider and the bandstop filter with one-dimension triangle and one-dimension sinusoidal.

碩士
國立聯合大學
電子工程學系碩士班
101
Microwave filter design frequently uses a lumped-element lowpass prototype, and a series of skills of transformation and approximation are then applied to achieve a distributed circuit that is suitable for layout realization. During the design process, filter’s design specifications are degraded,especially filter bandwidth. In order to enhance the bandwidth forecast, new method was proposed in a literature to reduce the shrinkage of bandwidth, and it was applied for the design of wideband parallel-coupled microstrip bandpass filter. In this paper, the proposed method is used to design two versions of filter that centered at 4GHz and having 50% fractional bandwidth. The circuit parameters of one of the two designs are determined by classical method, and the other one is determined by the literature-proposed method. Layouts of both designed are examined by electromagnetic simulator, implemented and verified by measurements.

碩士
義守大學
電機工程學系碩士班
99
In this thesis, dual-mode bandpass filters have been implemented by utilizing triangular patch and spur-line structures. The dual-mode filters are realized by utilizing the isosceles triangular patch to split two degenerate modes of the equilateral triangular patch. Further the two identical triangular patch resonator for the combined,and design two filters with different structures by 50 ohm transmission line with feed position.By the test results of area,we can found the triangular band-pass filter with feed from bottom is better than another.Then analyze characteristics with the structure were selected by test of cut off angle and regularity,found test of cut off angle have little effect on the triangular filter.We also found its can reduce the filter center frequency and improve the return loss and insertion loss with the type of bottom edge of length is less than a high by test results of regularity.Finally, investigate the structure of spur-line,and design and produce two kinds of dual-mode triangular band-pass filter.

碩士
大葉大學
電信工程學系碩士班
96
In the thesis, a miniature dual-mode microstrip bandpass filter with a center frequency of 2.5 GHz is designed by appropriately bending a circular ring inward. Next, proposed in this thesis is a dual-mode diplexer whose two paths are centered at 2.43 and 2.76 GHz, with their minimum insertion losses being 1.96 and 1.92 dB, respectively. Each of he two rings of the diplexer has been bent into triangular shape to save the circuit area.

碩士
國立臺灣大學
電信工程學研究所
93
In the beginning of this thesis, we design a compact and highly selective narrow-band filter. The highly selective response can be achieved by introducing transmission zeros which may be realized by cross coupling a pair of nonadjacent resonators of the filter. In addition, we design the diplexer by using the above-mentioned filter designed at 2GHz and 3GHz, respectively. The two filters are connected by the microstrip lines whose lengths have to satisfy appropriate phase condition. To reduce the diplexer size, stepped impedance resonators are adopted in the diplexer design. Through this way the eight resonators can be reduced to six. This diplexer, however, improves the size but degrades the isolation. Another way to reduce the diplexer size is that two filters share the same input stepped-impedance resonator. And the diplexer of this type not only has a more compact size but also keeps the very good performance. Thus we have verified that this is practical to combine two filters by using stepped impedance resonators in the diplexer design.

碩士
國立成功大學
電機工程學系碩博士班
91
To design a dual-band microstrip bandpass filter, one needs resonators and coupling structures with dual-band characteristics. Also, the matching problem of both bands at the input and output ports need to be solved. This thesis proposes a class of dual-band resonant structures based on the effect of stepped impedances. Then the resonators are bended and put close together to yield the needed dual-band coupling coefficients. To solve the matching problem of both bands, the thesis derives the formula of loaded Q of resonators and further proposes a modified dual-band inverter. If the ratio of second pass-band center frequency to the first one is between 1.5 and 2.5, the proposed structures and method can be used to design a second-order dual-band bandpass filter successfully.

碩士
國立高雄大學
電機工程學系碩士班
98
In this study, we propose a new matching circuit for mircostrip dual-passband by using the branch-line resonator which is consists of quarter-wavelength（λ/4） transmission lines, open stubs, and high passband resonator. The responses of resonance frequency of the branch-line resonators can fulfill individual specific center frequency of each passband. Especially, the quarter-wavelength（λ/4） transmission lines and open stubs designed in the matching circuits can provide an open circuit of high-band filter at the center frequency, and then the external quality factor of high-band can be extracted independently. Then the proposed dual-band filter would be implemented by designing the required coupling coefficients between adjacent resonators of each passband. Based on the above design concepts, the fractional bandwidth of each passbands can be separately designed and adjusted.

碩士
國立彰化師範大學
電子工程學系
94
In this thesis, we employ stepped-impedance resonators (SIRs) to design new single-band and multi-band microwave bandpass filters (BPFs) with high performance and reduced circuit size. For the single-band BPF, the asymmetric λ/2 SIR structure which consists of two different λ/4 SIRs is used as a building block. Two flexibly tunable transmission zeros are designed to be near the two passband edges to increase the skirt sharpness. One of the transmission zeros is due to the series resonance of the λ/4 open stepped-impedance stub; the other is produced by the anti-parallel coupling between adjacent SIRs. By appropriately choosing the SIR impedance ratio, the second passband (or the first spurious response) is pushed to a frequency of as high as 9.5 GHz. Thus wide stopband characteristic is achieved. For the dual-band BPFs, both second-order and fourth-order circuits are designed and investigated. The λ/4 SIRs which have a smaller circuit size and a larger third resonant frequency than that of the λ/2 SIRs are utilized for circuit design. With the aid of the relation of coupling coefficient and spacing between adjacent SIRs obtained from simulation and the Butterworth low-pass filter prototype parameters, the dual-band BPF is designed to have its two passbands located at the desired frequencies. In addition, the λ/4 SIRs are bent into a U-shape to reduce the circuit size. An anti-parallel coupling structure is also introduced to provide an additional transmission zero that lies between the two passbands. The latter is seen to be beneficial especially in enhancing the stopband rejection of the second-order dual-band BPF. For the last part of this thesis, we propose a new tri-band microstrip BPF with each of the coupling resonators composed of two λ/4 SIRs. The tri-band BPF can have its passbands designed at three arbitrarily useful frequencies and have the favorable features of tunable passbands and easy fabrication. In this design, the feed positions for the two ��/4 SIRs are carefully located to have the same distance from the via-hole ground and meanwhile to give the required external quality factors. In such a way, the microstripline sections between the via-hole and each of the feed positions can be combined into one to simplify the filter structure and to reduce the BPF circuit size. Results obtained in this research can be applied to commercially practical RF and microwave systems. The technique presented in this research is expected to serve as a useful reference for microwave filter designers in this and related research fields.

碩士
逢甲大學
通訊工程學系
103
This paper proposes three kinds of band-pass filter with high design freedom, miniaturization and low cost. The filters were successfully implemented on FR4 substrates with permittivity of 4.4 and thickness of 0.8 mm. They are all suitable for application in wireless communication. The first band-pass filter is a high selectivity ultra-wideband filter constructed by dual-mode stepped impedance resonator (SIR). At the beginning of the design, a stepped impedance resonator with dual-mode was used. Then we applied parallel coupling technique to improve the SIR into quad-mode. The input/output was made by interdigital way. At last, a pair of symmetrical type high-low impedance stubs were used to improve the pass-band sharpness. The communication frequency is 2.1-5GHz, and the fractional bandwidth achieves 90 percent. The dimension of the band-pass filter is 15mm × 16.65mm. The second band-pass filter is a compact tri-band band-pass filter using open stub- loaded and stepped impedance resonators. The first step is to utilize the open stub-loaded Resonators as the basic element, then embedded to the stepped impedance resonators to form a tri-mode resonators, and to adjust the pole of the location by the feeds. Controlling the bandwidth of the tri-band band-pass allow us to increase the selectivity. The band-pass filter can be utilized successfully in communication frequency operated in LTE (2500-2690MHz),WiMAX (3400-3700MHz),WLAN(5150-5350MHz). The dimension of the band-pass filter is 11.3mm × 12.3mm. The last band pass filter is a quad-channel diplexer. That is constructed by high-impedance type and low-impedance type stepped impedance resonators, afterward is connected through a quarter-wavelength impedance transformer line. Eventually, a quarter-wavelength open stub is added to improve the pass-band sharpness and also modify the isolation between the two outputs. Therefore, the band-pass filter can be used successfully in UMTS(1920-2170MHz),WLAN(2400-2488MHz,5150-5350MHz),LTE(2500-2690MHz),WiMAX(3400-3700MHz). The dimension of the diplexer is 30.95mm × 18.7mm. All of the designed band-pass filters mentioned in this paper have the well agreement between simulation and measurement, and can be used in the wireless communication products.

碩士
逢甲大學
通訊工程學系
104
This paper presents of microstrip bandpass filters with small size, and high selectivity. The filters have been realized on RT/Duroid 5880 substrate with a dielectric constant of 2.2, and a thickness of 0.787 mm. They are suitable for wireless communication applications. The first band-pass filter is a high selectivity and compact tri-band bandpass filter. The filter is composed of a multi-mode resonator and parallel coupling input/output strips. Through adjusting the coupling strip and length, we control the position of transmission zero. The method of source-load coupling is also used to add transmission zeros to improve the selectivity. The main size of the filter is only 17.6 mm × 16.4 mm. The bandpass filter can be applied in WLAN(2400-2488 MHz ; 5150-5300 MHz) and LTE(3400-3600 MHz) bands. Second, a diplexer constructed by stepped impedance resonators and uniform impedance resonators is proposed. The first design step is using a stepped impedance resonator to realize two pass band. Then, we use another stepped impedance resonator and uniform impedance resonator to filter out another unwanted passband individually. Finally, a quarter-wavelength open branch line is used to improve the isolation between the two outputs. The diplexer main size is only 19mm × 25.8mm. It can be applied in WLAN(2400-2488 MHz ; 5150-5300 MHz) bands. The third filter is a tri-band bandpass filter which is designed by using multipath asymmetric stub-loaded resonators. By changing the feeding position and the coupling space between resonators, the required bandwidth can be achieved. The source-load coupling technique is also used to add transmission zeros to improve selectivity. The main size of the filter is only 18.2mm × 22.3mm. The filter can be applied in LTE(2500-2690 MHz ; 3400-3600 MHz) and WLAN(5150-5300 MHz) bands. All of the filters are proposed in this paper have good agreement in the simulation and measurement. The characteristics of compact size and high selectivity make them suitable for application in communication products.

碩士
東海大學
電機工程學系
103
This paper proposes a type of design method that enables the realization of a multi-band miniature bandpass filter, primary using resonators with different characteristic to design dual-band, triple-band, and hepta-band miniature bandpass filters respectively. For verification, this paper uses stepped impedance resonators, bimodal resonators, and quad-mode resonators to achieve the miniaturized and multi-band functionalities. It also uses source-load coupling to create transmission zeroes, thereby attaining high selectivity. This design method not only significantly decreases the volume of resonators originally required, but it also increased the volume of operated bands. Microstrip structures were used to achieve all designed circuits, in which the circuit areas of the dual-band, triple-band, and hepta-band bandpass filters were 0.05 λg × 0.09 λg，0.12 λg × 0.13 λg， and 0.15 λg × 0.2 λg respectively. The final simulation and measurement results showed good consistency, thereby verifying this paper’s design concept.

碩士
國立成功大學
電機工程學系
90
Filters with asymmetric responses are very suitable for duplexer applications because they reduce the guard bandwidth and hence make the use of bandwidth more efficient. Trisection cross-coupled structures may implement responses of this kind because a transmission zero is created on one side of the passband and therefore make the side-band suppression better. Besides, the insertion loss on the passband is almost unchanged. The zero frequency could be controlled to be on the high side or the low side of the passband by modifying the coupling configuration adequately. In this thesis, filters of resonator type are designed and implemented by using microstrip. To reduce the circuit size, an I-shaped resonator is designed to be surrounded by the other two resonators. The I-shaped resonator is useful in the suppression of high-order resonant modes because it is similar to stepped-impedance resonators. The circuit layout becomes more compact after some modifications, and the transmission suppression on the close-in stopband is therefore improved.

Yes
Currently, several microwave filter designs contend for use in wireless communications. Among various microstrip filter designs, the reconfigurable planar filter presents more advantages and better prospects for communication applications, being compact in size, light-weight and cost-effective. Tuneable microwave filters can reduce the number of switches between electronic components. This paper presents a review of recent reconfigurable microwave filter designs, specifically on current advances in tuneable filters that involve high-quality factor resonator filters to control frequency, bandwidth and selectivity. The most important materials required for this field are also highlighted and surveyed. In addition, the main references for several types of tuneable microstrip filters are reported, especially related to new design technologies. Topics surveyed include microwave and millimetre wave designs for 4G and 5G applications, which use varactors and MEMSs technologies.
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement H2020-MSCA-ITN-2016 SECRET-722424.

碩士
義守大學
電機工程學系碩士班
99
In this thesis, Novel Microwave dual-band bandpass filters (BPF) are analyzed and designed for multi-band communication system. Utilizing the coupled stepped-impedance resonators (SIR) and defected ground structure (DGS). The resonator structure of coupling filter use stepped impedance resonator (SIR) and with modulation of the impedance ratio of the resonators for harmonics is controlled, the dual-band effect is obtained and with parallel-coupling structure to compare for transmission zero and reject bandwidth. In this case, coupling coefficient not only retrench the time of analyze the structure of resonators, but the method can synthesize the required filter under different circuit, only re-simulation the frequency responded and the coupling coefficient for resonator. Using the Tapped-in, it can make transmission zeros free and not calculate the filter parameter again. Finally, the bottom layer consist DGS to so depress stop-band of insertion loss that achieve the feature with harmonic full suppression, and effective control of filter frequency. According to design process, the operation bandpass filter center frequency is 2.45GHz and 5.25GHz, the method proposed in this paper that structure can effectively achieve the slim and simple from simulation and measurement results. The techniques presented in this research are expected to serve as a useful reference for microwave filter designers in this research fields.

碩士
國立臺灣科技大學
電子工程系
92
Abstract This research is about the design of microstrip dual-band bandpass filter. The main two kinds of microstrips of SIR（stepped impedance resonators） structure had been presented to improve. They are and SIRB（stepped impedance resonators bended） microstrip dual-band bandpass filter. Purposes are small size and high performance. For small size, SIR microstrip will be bended; for high performance, SIR microstrip will be matched. SIRB microstrip dual-band bandpass filter of 2-order has been reduced nearly 50% substantial area. The insertion loss of 2.4GHz frequency band is -0.17（min.）~-0.27（max.）dB. Bandwidth of 2.4GHz band is nearly 600MHz. Insertion loss of 5.2GHz frequency band is -0.7（min.）~-1.08（max.）dB. Bandwidth of 5.2GHz is nearly 450MHz. 40dB Shape Factor for 2.4GHz and 5.2GHz bands are equal to 0.27 and 0.23 respectively. In addition, SIRB microstrip dual-band bandpass filter of 2-order has also been reduced nearly 50% substantial area. The insertion loss of 2.4GHz frequency band is -0.1（min.）~-0.3（max.）dB. Bandwidth of 2.4GHz is nearly 830MHz. Insertion loss of 5.2GHz frequency band is -0.55（min.）~-0.89（max.）dB. Bandwidth of 5.2GHz is nearly 600MHz. 40dB Shape Factor for 2.4GHz and 5.2GHz bands are equal to 0.31 and 0.29 respectively.

碩士
長榮大學
資訊管理學系碩士班
98
Abstract—This thesis addresses a modified bandpass ring resonator filter providing compact size, low insertion-loss, wide band width, sharp rejection, and suppressed higher order modes. At first, we compare with subtract triangle and without. This morphologies are thought to have large influence on the filter effect for insertion-loss. On the other part, perturbation element size are proposed for the comparison of the influence on the effect of designed of filter. Also be understanding clearly of what kind of perturbation size for such substrate strong coupling by simulated and experimental results (insertion loss) At last, it is demonstrated that the use of internal folded stubs translates into an overall size reduction of more than 80% through the exploitation of the internal ring area. On the other hand, the compare of FR4, Al2O3 and La(Mg0.5Ti0.5)O3 substrate for insertion loss and a further advantage in terms of size reduction. Before Fabrication, we using IE3D software to simulated the filter center frequency f0 = 2.4GHz, bandwidth of 40 ~ 50% of the cases. We were fabricating the filter in FR4, Al2O3 ceramic substrate and the La(Mg0.5Ti0.5)O3 ceramic substrate and to discussion dielectric constant in size for the circuit had a better improvement. It is furthermore shown that electromagnetic simulations, transmission line model, as well as measurement results are in very good agreement.

碩士
義守大學
電機工程學系
102
This thesis presents a kind of band reject effects, etching back of defect ground structure (DGS) on FR4 substrate, used in parallel coupled bandpass filter. Improve on defect from the odd mode and even mode phase velocities are mismatch generate harmonic passband in the (2f0) and (3f0) . In addition, we found three DGS to change their size and find the effect of operating frequency in different shapes. Then we use the software of HFSS(High Frequency Structure Simulator) to design a parallel coupled bandpass filter in 2.5GHz of center frequency. The (2f0)5.02GHz and (3f0)7.32GHz appear on harmonic passband, by add DGS in parallel coupled bandpass filter. Finally, we take the FR4 substrate with DGS used in measurement and confirm defect ground structure can harmonic suppressions effectively, when attenuation take off to below -30dB.

碩士
樹德科技大學
電腦與通訊研究所
92
This thesis deals with how to design a two layers T-type microstrip bandpass filter and optimalize its performance .To reach filter this goad，several steps are set in this research. First，introduce IE3D simulator and descript all flow paths，commands，and core program in detail. Then analyze structure of a two layers T-type bandpass filter by using IE3D.All possible reasons for affecting the final performance are discussed. They include effect of T-type resonator，inverse U-type microstrip，double open stub and tap technology. Finally，the frequency response affected by the pattern location in different layer are investigated.

Dissertação de mest., Engenharia Eléctrica e Telecomunicações, Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2010
The need for networks able of integrating services such as voice, video, data and mobility is growing. To satisfy such needs wireless networks with a high data transmission capacity are required. An efficient solution for these broadband wireless networks is to transmit radio signals to the Base Stations (BS) via optical fiber using Wavelength Division Multiplexing (WDM). The WDM usage helps this growing, allowing the use of a single optical fiber to feed several BSs using for each one a different wavelength (or WDM channel). Additionally, in the RoFnet project in order to improve radio coverage within a cell, it is considered a sectorized antenna interface. The combination of subcarrier multiplexing (SCM) with WDM, further simplifies the network architecture, by using a specific wavelength channel to feed an individual BS and different subcarriers to drive the individual antenna sectors within the BS. This dissertation reports the design and simulation of the microstrip bandpass filters used at the BS on of the RoFnet demonstrator. These bandpass filters are used for the filtering of fours subcarrier multiplexed channels located at (9, 11, 13, 15 and 17 GHz). The design and simulation of the lowpass root raised cosine filter required for testing is also discussed. Additionally, the design and testing of two power splitter is reported. Finally, all the designed components were brought together and the overall BS performance is assessed. The microstrip components have been designed and simulated using both ADS (Agilent’s Advanced Design System) and Momentum simulators.

碩士
國立中正大學
電機工程研究所
101
This paper presents two designs. First, a novel design equations and examples of the modified arbitrary power ratio microstrip tandem coupler are presented. In order to obtain a wide passband, couplers with triple poles at the return loss are proposed. Compared to the conventional couplers such as Lange couplers and parallel coupled line couplers, high impedance transmission lines and narrow coupling gaps are not required for the proposed microstrip coupler. In terms of measured results, there is a wide bandwidth of more than 70%. Moreover, good agreement between theoretical predication and measurement validates our proposed structure. In the second design, a novel wide passband microstrip bandpass filter with broader stopbands is provided. The proposed bandpass filters is composed of the stepped coupled line and two short-circuited stubs. Each stage of electrical length of the stepped coupled line has been optimized and cascaded together for harmonic suppression. Moreover, the stepped coupled line with weak–strong–weak coupling results in a wide stopband. Furthermore, with short-circuited stubs connected at the input/output port, there is a steeper passband skirt and broader passband. In addition, the agreement between theoretical prediction and measurement validates our proposed structure.

碩士
國立成功大學
電機工程學系碩博士班
95
In general, the microstrip bandpass filters (BPF) suffer the problems of spurious responses in which the passbands and stopbands appear alternatively in the frequency spectrum. Suppressing the spurious responses effectively will remove the necessity of extra low-pass filters in front of or behind the bandpass filters. In this thesis we investigated the causes of the spurious responses and proposed a modified microstrip bandpass filter to enhance the capability of spurious responses suppression by using asymmetric stepped-impedance resonators. By choosing the proper stepped-impedance ratio and length ratio for the stepped-impedance resonators, the spurious responses beyond the desired passband can be suppressed effectively, resulting in the BPF with broad stopband. The HFSS simulation was first used to analyze the BPFs with symmetric and asymmetric stepped-impedance ratios and length ratios. The results showed that the stopband of asymmetric filters is wider that that of symmetric filters. The simulation also demonstrated that the spurious response suppression was almost the same for both zero degree and 180 degree signal feeds. The BPFs with spurious response suppression were realized on FR4, Al2O3 and BaZn2Ti4O11(BZT) substrates, respectively. The BPFs were designed with the characteristics of the center frequencies of 1.5 and 2.4 GHz, 8% bandwidth and the stopband with the suppression frequency five times over the center frequency. The measured results of the BPFs agreed with the simulations. However, the measured loss was larger than that of simulation due to fabrication errors. The shape factor of the filters was larger than two, which is a little bit over the accepted value for practical industry bandpass filters and needs further improvement in the future.

碩士
國立彰化師範大學
電信工程研究所
97
In this thesis, microwave bandpass filters (BPFs) designed on two metal laters of microwave substrates are presented. Three microwave filters, including one narrow band,one wideband BPF, and ome bandstop filter (BSF), were designed, implemented, and investigated. The narrow band BPF presented in the first part, the bandpass filters of coplanar waveguides (CPWs) combining microstrip with wide stop bandwidth were designed with the reaonant frequency set at 2.45 GHz for ISM band applications. The second BPF is fed by CPW. The multi-mode resonator (MMR) employed in this wideband BPF is formed by combining one coupled line and stepped-impedance resonator (SIR) load. Using microstrip-to-CPW feeding mechanism to provide strong enough capacitive coupling for bandwidth enhancement. In the final part of this thesis, we present the design of ring circuit BSF using λ/2 orλ/4 transmission lines to harmonic suppression. Results obtained in this research can be applied to commercially practical RF and microwave systems. The techniques presented in this resrarch are expected to serve as a useful reference for microwave filter designers in this and related research fields.

碩士
東海大學
電機工程學系
106
In this study, we proposed 5 different wideband bandpass filter which are all based on the stub loaded bandpass filter. They are type I (single stepped-impedance transmission line), type II (double stepped-impedance transmission line), type III (π shape transmission line), type IV (single T shape transmission line) and type V (double T shape transmission line). By using ABCD matrix, the transmission line of stub-loaded bandpass filter can be replaced by these 5 types transmission lines. Type I and type II filter are separately using single stepped impedance lines and double stepped impedance lines. Both of them have advantages such as compactness and wide stopband. Type III filter is using π shape transmission lines, this filter has advantage such as compactness. Type IV and type V are separately using single T transmission lines and double T transmission lines, both of them have the advantages such as compactness and wide stopband. These five types filters all have simulation and measured results, and a good agreement between simulations and measured results. Hence, if the requirement is wideband, compactness and wide stopband bandpass filter, these five filters are effective and feasible.

碩士
國立中正大學
物理研究所
83
By measuring the coupling coefficients(Ks) of interdigital resonators from empirical method and varing the spacing between two resonator, a curve of K verse S/H was obtained and a fitting curve K(S/H) was utilized to be given as initial values (spacing between two resonators of the interdigital filter) to optimize. A parallel-coupled-line approximation was also presented to design hairpin filters. The folded length(1mm) was fixed to connect two arms of a resonator. Owing to the folded length, more closer spacing between two adjacent resonators was needed. These designs were constructed and tested. Four examples are designed, two for interdigital filters and the others for hairpin filters. After optimizing by CAD(MDS),inter- digital filters and hairpin filters were realized.

碩士
國立中正大學
電機工程所
98
ABSTRACT In this thesis, we aim to design and develop a surface type microwave bandpass filter. Two different research efforts were explored towards designing a filter with Harmonic suppression. First was to exploit transmission zeros to design a single-band bandpass filter with wide stopband. Characteristic of such design is using a transmission line of 180-degree electrical length as its backbone, in addition to using parallel couple line with an open stub. In it, a symmetric coupled-line resonate was applied to generate resonate passband; thus a parallel couple line and an open stub can determine the transmission zeros. Our work better assists not only in computing of transmission zeros, but also in using J- inverter to analyze the equivalent circuits. Secondly, design of a single-band bandpass filter that retains the aforementioned 180-degree transmission line framework was further improved. Such attempt was observed a five-fold outperformance in Harmonic suppression. The augmented circuit used a parallel couple line concatenating an open stub for Harmonic suppression, thereby yielding an even wider stopband. The implementation was realized by using J- inverter to compute the equivalent circuits and employing transmission zeros to derive parameter settings. Our proposed scheme can build filters of a flexible design adapting to different demand scenarios. All filter designs were verified using a full-wave based electromagnetic simulator; subsequently, they were manufactured and evaluated. The simulated behaviors conform to actual measurements, as indicated from the experimental assessments. Keywords: single-band bandpass filter, parallel couple line, wide stopband, transmission zeros

碩士
國立交通大學
電信工程系
90
This thesis aims at designing microstrip bandpass filters with compact size. Coupled stages with folded lines are used. To make the effectiveness in reducing the circuit size as efficient as possible, both the width and gap of the coupled microstrip lines are chosen as small as possible. We analyze and compensate the folded resonators and coupled folded resonators, so that bandpass filters can be constructed with coupled multiple folded lines. A scheme for design coupled stages with an arbitrary coupled length is also incorporated into the design, for the convenience of resonator folding. Several Chebyshev filters of orders three and five are fabricated and measured to demonstrate the idea.

碩士
國立臺南大學
電機工程學系碩士班
100
Frequency-selective surfaces (FSS) is a periodic structure in two-dimensional space and it have been widely used in commercial communication applications. Based on slot ground defect design method, the filter can produce slow-wave effect to miniaturize component size. Such a structure can also increase spurious band suppression and provide flat stopband. In this paper, compact bandpass filters for Wireless Local Area Network (WLAN) and Industrial Scientific Medical (ISM) applications are successfully fabricated. A novel miniaturized adjustable dual-band filter based on Slot Ground Structure (SGS) is proposed and designed to operate at 2.45/5.7 GHz, respectively. The half-wavelength transmission lines combined with embedded structure are designed to create two resonant modes. The impedance matching for both resonant modes is further improved by using SGS. The use of meandering technology makes the designed dual-band filter more compact. The periodic metallic patch loop structures are filled into SGS. Such an implementation can be utilized to adjust the resonant frequency. To reduce component size, the use of via-hole and conductor-backed space is applied to produce a spiral transmission line. This spiral transmission line can create one resonant mode with operating frequency of 3.5-GHz. Without affecting the first and third pass-band, it can be utilized to create the second resonant frequency. Finally, a tri-band bandpass filter operated at 2.45/3.5/5.7-GHz is designed and fabricated. In this thesis, the designed bandpass filters follow the Institute of Electrical and Electronics Engineers (IEEE) standard, and can be applied to the existing wireless communication network.

碩士
國立臺北科技大學
電腦與通訊研究所
96
This thesis mainly focuses on the the structure of microstrip vertical transitions of circular cavity-couplers by changing the geometric shapes of slot aperture and microstrip terminated by open-circuited stubs，to achieve the purpose of bandwidth enhancement. By cascading other filter techniques can minimize the pass-band insertion loss and furthermore expand the rejection-band to 30 GHz，which allows this ultra broad-band band-pass filter to become high selectivity. The first model of stepped impedance low-pass filter, under certain modifications, can extend the range of rejection-band to attenuate the unnecessary signals to pass-band while the second model of low-pass filter, constructed of high quality slow-wave resonator, can effectively diminish the noises near the pass-band. Lastly, by using the interdigital from microstrip can further reduce the noises from other places. This paper uses FEM as a base to develop a stimulation of High Frequency Structure Simulation, which focuses on the past precise simulation experiences of the structure of microstrip vertical transitions, the results of such stimulation is yet to be proven from statistical results.

碩士
國立彰化師範大學
電子工程學系
95
In this thesis, multi-band microwave bandpass filters (BPFs) designed using cross-coupled stepped-impedance resonators (SIRs) were studied. Three microwave filters, including two dual-band and one tri-band BPFs were designed, implemented, and investigated. The first dual-band BPF circuit consists of a pair of L-shape half-wavelength ( ) stepped-impedance resonators (SIRs) and an inverted Z-shape resonator. The latter is actually a combined structure of two SIRs so designed to provide a magnetic coupling path and to reduce the circuit size. Cross-coupled SIR configuration and tapped-feed structures are adopted to introduce attenuation poles around the passband edges for selectivity improvement. A wider -20-dB upper stopband is achieved by properly separating the third resonant frequencies of the SIRs of different types. The second BPF proposed in this thesis was a compact fourth-order dual-band BPF having a wide upper-end stopband. Quarter-wavelength ( ) SIRs were employed to construct the BPF in order to have a relatively smaller circuit size and higher spurious passband, as compared with the BPF using SIRs. The resonators tapped by the input and output ports were loaded by a spur-line to suppress the first spurious passband so as to further broaden the upper-end stopband. BPFs with and without the embedded spur-lines were both simulated for comparison of their frequency responses. Finally, we presented in this thesis a second-order tri-band bandpass filter (BPF) designed using tri-section SIRs (TSSIRs). The impedance ratios of the TSSIRs were computed using the formula expressed as functions of the passband center frequencies, which are commercially practical and located at 1.57, 2.45, and 3.5 GHz. A cross-coupled configuration was arranged to sharpen the passband skirts. The newly designed tri-band BPF was verified by circuit implementation and very good agreement between the simulated and measured results was observed. Results obtained in this research can be applied to commercially practical RF and microwave systems. The techniques presented in this research are expected to serve as a useful reference for microwave filter designers in this and related research fields.

碩士
國立中正大學
電機工程研究所
102
This study is the design of wide-band bandpass filters with dual-path structure. By using the parallel coupled lines, the bandpass filters with a wide passband have been realized. Moreover, the combination of open stubs and transmission lines, the bandpass filters with a wide stopband can be achieved. In addition, all proposed filters are analyzed with J inverters method. In the first part, the two-path transmission line is provided for the design of bandpass filter. Different with the conventional two-path method which can generate only one transmission zero, the proposed method can generate two transmission zeros, and then a wide stopband will be obtained. In the second part, the two-path transmission line is replaced with the two-path coupled line, and then cascaded with three coupled lines. Because of the multiple transmission zeros can generate by the couple line, the harmonics can be suppressed and a wider bandstop will come out. All above mentioned circuits are simulated by using full-wave electromagnetic simulator IE3D, and the prototype of these circuits are fabricated and measured. The well-match results between electromagnetic simulation and measured data can evidence the availability of all proposed circuits. Keywords – Two-path coupled line, two-path transmission line, wide stopband, bandpass filter, transmission zero, harmonic suppression.

碩士
國立交通大學
電信工程系
91
Abstract Recent advances in wireless communication have created a need of high-performance filters with a dual-passband response. It is found that both the fundamental and first higher order resonant frequencies of a planar stepped-impedance resonator (SIR) can be easily adjusted by changing its structural parameters. Simultaneous synthesizing the two passbands for an SIR filter, however, is a challenge to circuit designers. In this thesis, we propose a method for designing SIR bandpass filters with a dual-passband response. The structural parameters of an SIR are determined by specified passbands. Then, in a filter, the gap and coupling length between two adjacent SIR’s are determined by the coupling coefficients specified by the design equations.