Electromagnetic simulation and beam-pattern optimization of a C-band Phased Array Feed for the Sardinia Radio Telescope

We report on results of electromagnetic co-simulations and beam-pattern optimization of the C-band PHAROS (PHased Arrays for Reflector Observing Systems) Phased Array Feed (PAF) from the primary focus of the 64-m diameter Sardinia Radio Telescope (SRT). We calculated the radiation patterns of a sub-array of 24 PHAROS Vivaldi array elements and propagated them through the reflector. We present the SRT far-field beam patterns obtained by Iinearly combining different PAF sub-array configurations with uniform weights. Furthermore, we used the Conjugate Field Matching (CFM) technique to derive optimum beam weights to maximize the SRT on-axis gain. The results show that the PHAROS array could be used at the focus of the SRT to provide high antenna performance, with high-quality illumination and efficiency greater than 60% across 4-8 GHz.

[1]  George Biddell Airy,et al.  On the diffraction of an object-glass with circular aperture , 1835 .

[2]  Lucio Rossi,et al.  Sardinia Radio Telescope: the new Italian project , 2004, SPIE Astronomical Telescopes + Instrumentation.

[3]  Y. Rahmat-Samii.  Array feeds for reflector surface distortion compensation: concepts and implementation , 1990, IEEE Antennas and Propagation Magazine.

[4]  J. Richard Fisher,et al.  Full-sampling array feeds for radio telescopes , 2000, Astronomical Telescopes and Instrumentation.

[5]  G. Naldi,et al.  Front-Ends and Phased Array Feeds for the Sardinia Radio Telescope , 2017 .

[6]  J. R. Fisher,et al.  Performance of a Highly Sensitive, 19-element, Dual-polarization, Cryogenic L-band Phased-array Feed on the Green Bank Telescope , 2018, 1803.04473.

[7]  G. Comoretto,et al.  The Sardinia Radio Telescope - From a technological project to a radio observatory , 2017, 1703.09673.

[8]  G. Comoretto,et al.  Design of PHAROS2 Phased Array Feed , 2018, 2018 2nd URSI Atlantic Radio Science Meeting (AT-RASC).

[9]  P. Hannan.  The element-gain paradox for a phased-array antenna , 1964 .

[10]  Lei Liu,et al.  Analysis of Vivaldi array antenna for phased array feeds application , 2017, 2017 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization for RF, Microwave, and Terahertz Applications (NEMO).

[11]  Ieee Microwave Theory,et al.  Quasioptical systems : Gaussian beam quasioptical propagation and applications , 1998 .

[12]  F. Giannini,et al.  A GaAs front-end receiver for radioastronomy applications , 2006, MELECON 2006 - 2006 IEEE Mediterranean Electrotechnical Conference.

[13]  N. Roddis,et al.  Design of a Focal Plane Array system at cryogenic temperatures , 2006, 2006 First European Conference on Antennas and Propagation.

[14]  Karl F. Warnick,et al.  High-Sensitivity Phased Array Receivers for Radio Astronomy , 2016, Proceedings of the IEEE.

[15]  N. Roddis,et al.  Beamformer system model of focal plane arrays in deep dish radio telescopes , 2005, 2005 European Microwave Conference.