Wideband design and thermal deformation analysis of space-borne large waveguide slots array antenna in Ku-band

Waveguide slots array antenna was adopted in engineering project. Though this antenna had high gain, low side lobe etc, wideband requirement was a big challenge for it. As working in the space environment, large space-borne antenna would be influenced by the thermal deformation. It was necessary to analyze the influence on electrical performance, such as radiation pattern. In order to enlarge the band, antenna was separated into four areas to feed, and the feeding point was in the center of the waveguide. Special loads were exerted in waveguide H-T and E-T junctions to meet impedance matching. An approximate computation method was provided to analyze the influence of the thermal deformation on antenna performance. Some 8×10 slots array antennas were manufactured as the first step, and these antennas were tested in our near field testing system. The bandwidth of the Voltage Standing Wave Ratio (VSWR) below 1.3 was 340MHz, and the side lobe level was -25.9dB in E plane and -27.2dB in H plane. Measurement result indicated the availability of the designe.