Design of a Dual-Polarized Microstrip Antenna with Low Backward Radiation

Design method and key technologies of a Ku wide band dual-polarized microstrip antenna with high gain, low back lobe, high port isolation and polarization isolation are given in this paper. To realize Dual-polarization, the antenna is fed by a cross coupling slot. This microstrip antenna consists of a fourlayer structure. To reduce the radiation effect, the feeding lines are placed on the side of ground layer. Compared with conventional microstrip antenna, this improved antenna exhibits higher radiation gain and front-to-back ratio with similar characters on bandwidth, port isolation and polarization isolation. Test results of the improved antenna shows that the gain is above 6.85dBi with 500MHz bandwidth (VSWR <1.5), the isolation of two ports is -53dBc, the polarization isolation is 55dBc, and the front-to-back ratio is 21dBc.