Design of a Wideband Stack Array Antenna For Ka-band Satellite Communication Application

This article presents the design of circularly polarized array antenna with the stack microstrip which works at Ka-band frequency of wideband for satellite communication application. So as to get a greater bandwidth which is demanded to include the Ka-band spectrum electromagnetic ranges of the frequency of 27 ~31 GHz, the technology of dual-layer substrate was taken advantage of. The antenna element consists of two layers parasitic circular radiator. The top patch is 2.5 mm of diameter. The bottom patch is 3.4 mm of diameter with the two side grooves of circular patch. An array of $2 \times 2$ antenna which is continuously rotated shows a 100% (24 GHz ~34 GHz) broadband 1-dB axial ratio bandwidth and 25.6%(25.5GHz ~33GHz) broadband at 2:1-VSWR. Between 26.5 GHz and 32.5 GHz, a gain which is 11 ~12.2 dB in axial direction is obtained. An array of $8 \times 8$ antenna shows a gain which is in axial direction exceeds 22 dB between 26.0 GHz ~33.0 GHz.