Dissertations / Theses on the topic 'Broadband Tracking Antenna Feed'

International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada
Two different types of tracking feeds are currently used in the majority of telemetry tracking antenna systems when autotrack operation is required. They are of the conical scanner or of the single channel monopulse family and they employ well known technologies. In broadband applications, these feeds all suffer from the same inherent degradation in efficiency caused by their inability to maintain a constant crossover loss value and by their failure to properly illuminate the reflector. In high dynamics situations they can also generate unwanted and sometimes detrimental modulation whenever on-axis tracking is not maintained. In addition, currently available versions of the conical scanner are not capable of high scan rates or of scan rate agility and they are ill-suited for use in tracking systems based on non-orthogonal axes positioners. This paper describes a new high efficiency tracking feed system based on proven conical scanner technology. Its design incorporates features such as variable crossover, steerable beam, high scan rates, scan rate agility as well as stable reference coordinate system. In addition to these features, this new feed is also capable of delivering, in all but one operational category, levels of performance superior to that achievable to date by any other implementation of the conical scanner or of the single channel monopulse technology.

This thesis describes the development of a log-periodic waveguide feed antenna from concept to design and finally to prototyping and testing. An electromagnetic simulator (CST) was used to evaluate different design concepts and a design based on a nested coaxial waveguide structure was selected. A design was developed that included a common excitation structure for all the waveguides and an aperture matching structure that scales periodically with frequency. In the design, each waveguide has a bandwidth ratio of 2:1 and the total bandwidth of the design is 1 GHz to 8 GHz. A physical model was created using the SolidWorks design software and a prototype was manufactured and tested. Simulation results were in good agreement with the experimental results over the majority of the antenna's bandwidth. The antenna design had good farfield patterns across most of the antenna's bandwidth with frequency-specific farfield issues. The return loss of the antenna varied greatly with frequency, being greater than 2 dB across the entire bandwidth of the antenna and greater than 6 dB for the majority of the bandwidth of the antenna. There were significant difficulties in achieving a good return loss at the aperture which limited the return loss of the antenna. This work demonstrates the potential of employing a nested coaxial waveguide structure for wideband feed applications.

International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada
The use of low windload FLAPS™ antennas in telemetry tracking systems yields sizable savings in system cost due to the reduced requirements imposed on the pedestal assembly and on the underlying support structure. Traditionally the use of these antennas has been limited to applications in which frequency bandwidths did not exceed 10-13%. This paper describes a variation of the FLAPS™ technology which allows operation over bandwidths in excess of 35% and makes it usable in broadband systems. Two new applications are feasible: one for a ground based telemetry system operating in the 1435-1850 or 1750-2400 MHz band and one for a shipboard satellite communication system operating in the 4000-6000 MHz band.

Thesis (MScEng)-- Stellenbosch University, 2013.
ENGLISH ABSTRACT: This thesis presents a thorough study of the printed sinuous antenna and its characterisation as a feed for re ector antenna applications. Two di erent techniques are used in this study, namely a parametric study and an e cient surrogate based optimisation strategy. A planar sinuous antenna over a re ecting ground plane, with no absorber lining, is designed following a parameter study from which e ective design guidelines are derived. The designed prototype displays a bandwidth ratio of more than 3 : 1 from 1:9􀀀6:2 GHz, at a measured return loss of 10 dB, representing a signi cant improvement over the octave band previously achieved with a similar antenna. An optimisation based approach is followed in formally investigating a conical sinuous antenna over a re ecting ground plane. An e cient surrogate based optimisation strategy, in which the antenna's response is approximated by a Kriging model, is used. The search for optimal design parameters as well as improvements in the accuracy of the Kriging model is accomplished by using expected improvement as the in ll sampling criterion. The antenna is optimised for return loss, aperture e ciency for a prime-focus paraboloid re ector as well as cross-polarisation and results from the optimisation are used to derive e ective design guidelines and performance limitations. The investigations are conducted for the 2 􀀀 6 GHz band and the obtained results can be easily applied for designs with wider bandwidths. Simulation results reveal improved return loss, aperture e ciency and cross-polarisation performances compared to what has previously been reported for this antenna.
AFRIKAANSE OPSOMMING: Hierdie tesis bied 'n deeglike studie van die gedrukte stroombaanbord sinuous antenna, sowel as die karakterisering daarvan as voer vir re ektor antenna toepassings. Twee verskillende tegnieke word gebruik, naamlik 'n parametriese studie en 'n surrogaat-gebaseerde optimering strategie. E ektiewe doeleindes vir die ontwerp is van 'n parameter studie afgelei, waarvolgends 'n planêre sinuous antenna met 'n weerkaatsingsgrondvlak ontwerp is sonder enige absorberende materiale. Die prototipe vertoon beter as 'n 3 : 1 bandwydte van 1:9 GHz tot 6:2 GHz teen 'n gemete weerkaatsingskoë siënt van beter as 􀀀10 dB, wat dui op 'n aansienlike verbetering teenoor die oktaaf bandwydte wat voorheen met 'n soorgelyke antenna bereik is. 'n Optimering-gebaseerde benadering is gebruik om ondersoek in te stel in die gebruik van 'n koniese sinuous antenna met 'n weerkaatsingsgrondvlak. 'n Doeltre ende surrogaat-gebaseerde optimeering strategie is gebruik, waar die antenna se weergawe deur 'n Kriging model benader word. Die verwagte verbetering is gebruik as maatstaf in die soektog vir optimale ontwerpsparameters, sowel as om die akkuraatheid van die Kriging model te verbeter. Die antenna is geoptimeer vir sy weerkaatsingskoë siënt, stralingsvlak e ektiwiteit for 'n paraboloïed antenna sowel as kruispolarisasie. Resultate van die optimering is gebruik om e ektiewe riglyne vir die ontwerp en grense vir die werkverrigting op te stel. Die antenna is ondersoek vir die 2 tot 6 GHz frekwensieband en die resultate wat verkry is kan maklik op ontwerpe met selfs wyer bandwydtes toegepas word. Simulasie resultate dui op 'n verbetering in weerkaatsingskoë siënt, stralingsvlak e ektiwiteit en kruispolarisasie in vergelyking met wat berig is vir hierdie antenna.

ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California
A new common aperture autotracking C-band feed, specifically designed to accurately track fast moving targets such as the Lance missile, is reviewed. Measured data demonstrates exceptional tracking modulation required for good tracking performance while simultaneously providing excellent data channel performance for high G/T over the entire 4.40-5.25 GHz band. The new patent applied for feed design allows users to maintain existing L/S-band capability with a cost effective field upgrade which adds high performance C-band capability to an existing telemetry tracking system.

碩士
明新科技大學
電機工程系碩士班
104
In this thesis, we study separately the asymmetric coplanar waveguide fed and the U-shaped coplanar waveguide fed monopole slot antennas. The Implement of antenna is carried out with printing circuit boards, which are easy to be integrated, low cost and enhancing convenience production characteristics. In this study, two different locations of feed are applied for the monopole slot antenna. The resonant modes of the antenna are excited by different current paths. In asymmetric coplanar waveguide feed case, by changing the location and shape of the feed, the asymmetric coplanar waveguide fed monopole slot antenna has operating frequency from 2.55GHz to 6.2GHz with operating bandwidth 85%. The U-shaped coplanar waveguide fed monopole slot antenna has operating frequency between 2.3GHz and 5.4GHz with bandwidth is 82%. The operating bands of these antennas are including Bluetooth ,WLAN and WI-MAX, which can be applied for wireless network. The bandwidth is more than 25% (500MHz above) and fits in the definition of ultra wide band.

碩士
大葉大學
電機工程學系
107
In this study, we explore a CPW-feed broadband circularly polarized antenna. The simulation is simulated by ANSYS HFSS and ALTAIR FEKO. We compare those results with measurements data. This antenna are composed of two L-shape unbalanced ground planes and a 50Ω mircostrip line. We fine tune the unbalanced ground and slot to obtain 50Ω input impedance of this antenna. This antenna covered 1.85 GHz~3.95 GHz broadband circularly polarized , which is applied for LTE(Long Term Evolution) 2.3 GHz ~ 2.7 GHz and WiMAX(2.5 GHz ~ 2.69 GHz).

碩士
國立交通大學
電信工程研究所
103
An S-band auto-tracking antenna feed for mono-pulse ground station is presented. The uplink band is from 2.025 to 2.12 GHz and the downlink one is from 2.2 to 2.3 GHz. The feed is utilized to modify the orientation angle of the antenna to align antenna boresight with a satellite. According to the mono-pulse radar theory, the system structure can be divided into two parts of sum and difference channels. The part of sum channel is used for data transmission and the key component is a septum polarizer which generates circular polarized electric fields. For the miniature purpose, we choose a septum polarizer instead of OMT structures. The other part of difference channel is used for modifying the angle and the key component is a TE21 tracking coupler with the highest mode, TE21 mode. Between the septum polarizer and the tracking coupler, there is a taper structure for suppressing unwanted higher order modes passing down to the polarizer. The simulated results show that the VSWR is below 1.5. The calculated results show the polarization isolation is larger than 20 dB, and the axial ratio is smaller than 1.5 dB in boresight direction.

碩士
國立臺灣科技大學
電子工程系
106
This paper proposes to apply to the 77GHz anti-collision radar short-range antenna, the operating frequency band is 77GHz to 81GHz, using the array antenna as the basic structure of this antenna, and using the multi-layer board design to reduce the overall required area, in the overall vehicle radar system In the frequency range of 76 GHz to 81 GHz, the reflection coefficient can reach below -10 dB. The antenna gain can reach 14.2dBi, and in the operating frequency range of 77GHz to 81GHz, the radiation efficiency can reach more than 85%.

碩士
大葉大學
電機工程學系
107
This paper make use of C-Band in Circularly polarized antennas research that use HFSS software. This antenna composed of rectangle slot ground plane and microstrip line. Focus on design of Asymmetry feed and ground plane, make the ground plane and antenna emerge right angle phase difference of orthogonality, Circularly polarized is generated. Analysis result of antenna apply to C-Band that reflection Roefficient coverage (3.7~10)GHz and Axial ratio coverage (4.6~6.9)GHz.

碩士
國立交通大學
電信工程研究所
101
In this thesis, we proposed a broadband and wide-beam short-range antenna structure used in the 77GHz automotive collision warning radar. The bandwidth of the short-range antenna is from 77 to 81GHz. The antenna can detect short-range distance and wide angle of view from once own lane. The basic structure of the short-range antenna is an array antenna. In the end of the array antenna is an insert patch antenna which can provide broadband impedance matching. With the corporate feeding, the gain bandwidth can be wider. Finally, by using dual parasitic elements, not only the antenna beamwidth can cover from -45 degrees to 45 degrees but also the impedance matching and radiation efficiency can be improved to enhance antenna gain.

博士
國立交通大學
電信工程研究所
107
This dissertation is focused on the design of a miniaturized S-band monopulse tracking antenna feed for tracking low earth orbit satellites and communicating. The proposed antenna feed is compact and light, which is suitable for using in the Cassegrain antenna system. Moreover, designs of monopulse tracking circuits and frequency-selective subreflector are also proposed, and the principle of monopluse tracking is discussed. In the first stage of this dissertation, several techniques to track targets are introduced and discussed. The simplest type of monopulse technique is the simultaneous lobing system, which utilizes amplitude comparison. The conventional method for creating difference patterns was similar to radar tracking through the phase combination of multiple horns, such as a 2 × 2 horn array. Such methods generally require complex phasing network arrangements and four-aperture antenna arrangements. However, a circular waveguide or a coaxial line also can create difference patterns if higher order modes can be generated. Hence, multiple horns can be reduced to only one aperture to ensure that the design is simple and compact. We propose a compact S-band monopusle tracking antenna feed using two-hole Bethe hole coupler, which is composed of a horn antenna, a TE21 tracking coupler, a waveguide taper, a septum polarizer, and signal combining circuits. The antenna feed is used in a 3.7-m Cassegrain antenna system. The uplink band of the antenna feed ranges 2.025–2.12 GHz, and the downlink/tracking band ranges 2.2–2.3 GHz. Secondly, considering the weight of the S-band monopulse tracking antenna feed and the need for minimizing the blockage of the antenna systems, a miniaturized S-band tracking antenna feed must be designed with acceptable antenna performance. We fabricate the TE21 tracking coupler by using the structure of a coaxial line. The inner metal of the coaxial line is a circular waveguide. With an appropriate size of the aperture, the TE11 modes can exist in the circular waveguide while the TE21 waveguide mode becomes an evanescent mode. A metal cylinder is added as an outer shield to form a coaxial line for tracking targets. Because the wavelengths of the TE11 and TE21 modes in a coaxial line depend on the inside diameter of the shield, the shield is designed to be small as possible so that the difference between the wavelengths of the TE11 and TE21 modes is as large as possible. At the end of the coaxial line is a metal plate connected to the circular waveguide and the cylindrical metal shield as a short-circuited wall, the length of the coaxial line is designed to be one wavelength of the TE11 coaxial mode. It seems that there is a virtual short-circuited wall at the open end of the coaxial line to prevent the leakage of the TE11 waveguide mode into the coaxial line. To reduce the coupling of the electric fields of the TE11 coaxial mode in the probe feeds, the distance between the metal plate and probe feeds is set to be equal to a half-wavelength of the TE11 coaxial mode. Hence, there is a virtual short-circuited wall near the probe feeds for the TE11 coaxial mode but not for the TE21 coaxial mode. Then, the antenna feed is used in a 6-m Cassegrain antenna system. The simulated antenna gain of the sum patterns is about 39.1 dBic. The 1-dB-beamwidth is 1 degree and the simulated axial ratios are lower than 1.1 dB within 0.5 degree range. Moreover, the principle of monopulse tracking is proposed to analyzing the characteristic of the CP electric fields of the TE11 waveguide mode and the TE21 coaxial mode in the far field. According to monopulse theory, the changes of the angles of tracking targets can be detected and the orientation angle of the 6-m dish antenna can be modified to align the antenna boresight with the LEO satellites. The input signals are received from sum and difference patterns and combined in a power combiner. The voltage value of the combined signal is obtained by an analog detector and then sampled by the ADC. The MCU is acted like a digital signal processor and control the phase shifter in different phases. In the last part of the dissertation, when an equivalent inductor and a capacitor of lumped circuits printed on each side of a substrate, it is equivalent to a band-pass filter at a certain frequency. Using two square loops printed on one side of a substrate, a transmission zero is created in the out-band which improves the performance. The simulated results fit the requirements. To prove the right of our design, we change the substrate as FR4 and redesign the dimensions of the structure. Because the antenna gain of the transmitted/received antenna is small with wide antenna beamwidth, the transmitted wave is easily affected by the reflected waves in the environment. Hence, the measured results are vibrated seriously but still fit the simulated results.