A Bidirectional Microstrip X-Band Antenna Array on Liquid Crystal Polymer for Beamforming Applications

This communication presents for the first time a 16-element planar X-band bidirectional antenna array for beamforming applications. The planar (2D) antenna array is comprised of planar polygon slot antenna elements that utilize a metamaterial inspired reactive coupling element. Simulation and measurement results are presented for both a single antenna element and a 16-element planar array, which resides on a Liquid Crystal Polymer (LCP) substrate. Successful comparison between measured and simulated results verifies that the single antenna element achieves a 10 dB return loss bandwidth of 17.5% and the planar antenna array achieves a 10 dB return loss bandwidth of 25% both at a center frequency of approximately 11 GHz. The measured gain of the planar antenna array is more than 14.5 dBi with an efficiency of 65%. The overall size of the planar antenna array is 3.3λ_° × 3.6λ_° × 0.0093λ_° at 11 GHz.