Subarray Optimization for Compactness Improvement of a 3D Printed Adaptive Phased Array Antenna Operating in Ku-band

In this work, a 1-port waveguide 40-slot array is divided into twenty subarrays in order to meet the requirements of an adaptive phased array antenna dedicated to a radar seeker application in the Ku-band. The subarray consists in a cavity backed 2-slot antenna. The cavity shape is optimized in order to gain compactness without deteriorating the performances of the antenna. For this purpose, three subarrays are proposed. As a proof of concept, the initial mechanically-steerable 1-port antenna as well as the three proposed subarray versions are manufactured using a Stereo-Lithography Apparatus 3D printing technology (SLA) followed by metallization steps. For similar performances, namely a 10 dB in-axis realized gain, the third proposed subarray version provides a 7.5% compactness improvement of the final 20-port phased array antenna in comparison with the initial 1-port slotted waveguide array while preserving a 23 dB in-axis realized gain and a low side lobes level.