Dual-band Dual-polarized Two-layer Microstrip Patch Antenna with Dual-port Feeding

In this paper, a dual-band dual-polarized microstrip patch antenna is proposed. The antenna is composed of two-layer printed-circuit boards. Two mutually perpendicular microstrip lines are used for feeding on the top of the lower-bottom printed-circuit board, and four symmetrical equal square patches are placed on the top of the upper printed-circuit board. The proposed antenna has two frequency bands. The first center frequency is 4.32 GHz and the second center frequency is 5.86 GHz. The port isolation of the antenna is larger than 15dB in both working bands. The suggested antenna has linear polarization as its polarization characteristic. It shows perfect radiation performance in two frequency bands, where the difference between co-polarization and cross-polarization in the principal radiation direction is larger than 20dB.