Dual-Polarized Waveguide-Based Array Antenna for D-Band Applications

This paper presents simulation, fabrication, and measurement results of a dual-polarized <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1 \times 16$</tex> array antenna based on corporate hollow waveguide feed network for operation over 131 GHz to 140 GHz. To support two orthogonal modes, the antenna is designed based on square waveguide. Different tuning parameters are introduced and optimized to improve impedance matching of vertical and horizontal polarizations and match them to -10 dB, independently. The antenna is compact with a total size of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$13 ~\text{mm} \times 22 ~\text{mm}$</tex> with a small element spacing of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.62 \lambda$</tex> at the center of the band. Simulation results show return loss of less than almost -10 dB and gain of over 19 dBi for both modes with 3 dB beamwidth of 70 deg. and 5 deg. for E - and H -planes, respectively. To fabricate and measure the designed prototype, an orthomode transducer has been designed and integrated with the antenna. The structure has been fabricated using conventional 3D printing technique on stainless steel to validate the computed results.