Design of Multifunction Antennas in A Common-Aperture

A common-aperture antenna that can work in the S-band and UHF band is proposed in this paper. The antenna that works in the S-band consists of a circular patch, a square slot, and a square support post. It is fed by two coaxial cables to achieve circular polarization. Slot antennas that operate in the UHF band are coplanar waveguide excitation. Two pieces of inverted L-shaped patches were implanted into the square grooves to achieve dual circular polarization characteristics. The feeder is terminated on an inverted L-shaped patch. In addition, two rectangular slots were added at the corners of the antenna to improve the bandwidth of the axial ratio (AR) and voltage standing wave ratio (VSWR). Simulation results show that when working in the S-band, the frequency range of VSWR < 2.8 is 1.9GHz-2.5GHz, and the gain is about 8dB. When working in the UHF band, the frequency range of VSWR < 3 is 0.66GHz-1.10GHz, and the gain is about 5dB. This antenna has the characteristics of small size, light weight and high isolation.