Tri-reflector Compact Antenna Test Range Research Articles

A Novel Universal Applicability Design Method for Low Cross-Polarization Terahertz Tri-Reflector CATR

In this paper, a novel design approach with universal applicability is proposed for realizing a low cross-polarized terahertz tri-reflector compact antenna test range (CATR). This approach not only enables the radiation direction of the feed relative to the main reflector to be designed arbitrarily but also enables the designed CATR systems corresponding to different feed rotation angles while still maintaining a low cross-polarization. By using the beam mode analysis method and cross-polarization elimination conditions, the geometric configurations of the tri-reflector CATR can be designed for feeds in any different rotation angles, and then according to the kinematic and dynamic ray-tracing method with frequency independence in geometric optics, shaped subreflectors can also be synthesized. Through the above design procedure, four tri-reflector CATRs corresponding to four different feed rotation angles have been achieved, respectively. Numerical simulation results show that the cross-polarizations of four tri-reflector CATRs are all less than –38 dB and the peak-to-peak amplitude (phase) ripples of the quiet zone (QZ) are all within 1 dB (10°) in the frequency range of 100–500 GHz. This demonstrates the effectiveness and universal applicability of the proposed design method in realizing the design of low cross-polarization and good QZ performance for tri-reflector CATRs with different feed rotation angles.

Design of Low Cross-Polarization Tri-Reflector CATR with Standard Quadric Surfaces Working in Terahertz

In this paper, a tri-reflector compact antenna test range (CATR) consisting of a main parabolic reflector with a square aperture of 3 m in side length and two sub-reflectors of rotationally standard quadric surfaces working in terahertz is proposed. By using the equivalent paraboloid theory and cross-polarization elimination conditions and then combining with the appropriate shaped feed, the low cross-polarization and good quiet zone (QZ) performance of the system are achieved. The simulated results demonstrate that a cross-polarization isolation of >37 dB and a peak-to-peak amplitude (phase) ripple of <1.8 dB (13°) can be achieved on the principal cuts of the QZ at 100–500 GHz. At the same time, the QZ usage ratio of the CATR can reach 75%. The proposed tri-reflector CATR composed of standard quadric surfaces not only exhibits good quiet zone performance but also greatly reduces the manufacturing difficulty of the sub-reflectors and the construction cost of the system.

Numerical synthesis of tri‐reflector CATR with high cross‐polarisation isolation

In this Letter, a tri-reflector compact antenna test range (CATR) with a paraboloidal main reflector and two shaped sub-reflectors is synthesised by the kinematic and dynamic ray tracing method, while the high cross-polarisation isolation is achieved through the proposed system geometry. Numerical simulations by general responsibility assignment software patterns demonstrate that a cross-polarisation isolation >40 dB and a peak-to-peak amplitude (phase) ripple <1 dB (10°) can be achieved on the principal cuts of the designed quiet zone at 90–325 GHz. This clearly shows that the high cross-polarisation isolation in such a tri-reflector CATR can be achieved by the proposed antenna geometry without depolarisation control in the shaping procedure.

In brief

PAGE 1325 A passive device presented by a team from RWTH Aachen University, Germany, will enable an increase in the efficiency of solar panels. By integrating antennas with solar panels, the team were able to adjust the angle of the panel as well as the antenna autonomously. This integration allows more effective power collection without comprising the radio link. PAGE 1353 In a letter from the Graduate School of Advanced Sciences of Matter, Japan, the performance of a 300 GHz CMOS transmitter is reported. The frequency band above 275 GHz currently remains unallocated, as transmission at those frequencies has been difficult to realise. The team's letter shows that this spectrum allocation is now certainly worthy of further discussion. The proposed device operates up to a rotation of ±45° PAGE 1342 An X-band gallium-nitride high electron mobility transistor transformer-based Doherty power amplifier (TBD PA) module with a phase lineariser has been presented. This was developed by a team from Seoul National University, Korea, to overcome the difficulties faced in developing a millimetre-wave PA that covers wideband modulation signals. The CMOS transmitter turns out to be comparable in performance to other 0.3 THz or higher systems PAGE 1286 A letter reporting collaborative work undertaken by Beijing University of Posts and Telecommunications, China, and Queen Mary University, London, United Kingdom, clearly demonstrates that low cross-polarisation in a tri-reflector compact antenna test range (CATR) can be achieved with appropriate antenna geometry. It also shows that strategies for cross-polarisation control in the shaping procedure can be avoided. A future communication standard such as fifth generation is expected to be realised at frequency-band of millimetre-waves PAGE 1290 A team from the Indian Institute of Information Technology present a method of pattern retrieval for computed tomography images. One way to analyse an image is to compare it with similar images from a database, and the team used dissimilarities between the images to improve comparison. Novel antenna geometry can be used to overcome the problems faced by CATRs Images from computed tomography are among the most important source of information for medical analysis

Numerical and experimental verification of a trireflector compact antenna test range in the terahertz band

ABSTRACTNumerical and measured results of the quiet zone performance of a trireflector compact antenna test range (CATR) system in the terahertz band are presented in this letter. A modular Gaussian beam (GB) analysis method, which consists of frame‐based Gabor transformation, GB reflection and a 3D GB diffraction technique, was implemented to evaluate the quiet zone performance. Compared to geometrical optics method, this method is valid in predicting the field distribution in the caustic region. Moreover, simulation results of the CATR system demonstrated a superior efficiency to the physic optics method, especially in the terahertz range. Measured results show that 70% quiet zone usage can be achieved with amplitude and phase ripples less than 1.2 dB and 15°, respectively in the central frequencies. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1686–1689, 2015

Optimisation of cross-polarisation performance for tri-reflector CATR with spherical main reflector

For a tri-reflector compact antenna test range (CATR) with spherical main reflector and shaped subreflectors, the cross-polarisation performance is optimised, based on the beam-mode expansion method. For optimal designs, physical optics (PO) calculations of the quiet zone fields are presented, and it is shown that a tradeoff has to be made between a low cross-polarisation level and a low amplitude ripple in the quiet zone.