Ka-band microstrip array antenna with compact series-parallel hybrid strip-line feeding network

This study proposes a Ka-band high-performance microstrip array antenna having a planar array front-end and strip-line back-end. 10 × 4 hybrid-fed rectangular patches with Taylor-synthesized excitation is adopted to form weighted patterns. Preferable symmetrical patterns are obtained covering 34.5–35.5 GHz working band due to the symmetric feeding arrangement. The measured reflection coefficient is lower than −10 dB, and peak co-polarization gain and first side-lobe level are better than 19 dB and −17 dB, respectively. Additionally, the strip-line back-end ensures an ideal front-to-back ratio of approximately 40 dB. The measurement results coincide with the simulation results, proving the immense prospect of our design in airspace detection or other applicable scenarios.