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Matched feeds for offset reflector antenna using circular microstrip patch antenna
Author(s) -
Debbarma Kaushik,
Bhattacharjee Ratnajit
Publication year - 2019
Publication title -
international journal of rf and microwave computer‐aided engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.335
H-Index - 39
eISSN - 1099-047X
pISSN - 1096-4290
DOI - 10.1002/mmce.21909
Subject(s) - hfss , offset (computer science) , optics , offset dish antenna , microstrip , microstrip antenna , reflector (photography) , patch antenna , physics , acoustics , computer science , periscope antenna , antenna (radio) , telecommunications , light source , programming language
This article presents two designs of matched feed for an offset fed reflector. Circular microstrip patch antennas are used in the proposed designs. Both the matched feeds achieve conjugate field matching by generating TM 21 mode at an appropriate ratio to the fundamental TM 11 mode. The first matched feed generates the required dual mode field distributions using a dual layer stacked patch antenna. The second matched feed is a novel design using centered circular array with the central element generating the required TM 21 mode and the surrounding circular ring antenna elements operating in the TM 11 mode. Both the designs are studied analytically using cavity model and are implemented in High frequency System Simulator (HFSS) and Computer Simulation Technology (CST). The matched feed designs are investigated for an offset reflector with the projected diameter, D = 50λ, focal length, F = 30λ and clearance height, H = 5λ operating at 20 GHz. The secondary field patterns of the offset reflector fed by the matched feeds are evaluated numerically using a MATLAB code based on geometrical optics technique and verified by HFSS‐PO results. Offset reflector performance such as cross‐polarization, −30 dB cross‐polar bandwidth, gain, and first side‐lobe level are investigated for the both matched feeds.