Dual-Polarized Dual-Band Microstrip Antenna With Similar-Shaped Radiation Pattern

A dual-polarized dual-band (DPDB) microstrip antenna with two orthogonal feeding ports and similar-shaped radiation pattern is studied. The working mechanism of the dual-band operation and the similar-shaped radiation pattern is analyzed based on the S-parameters and the electric field distributions, respectively. A prototype shows that the measured impedance bandwidths for ${\text{VSWR}} < {2}$ are 150 MHz (810–960 MHz, 17%) and 550 MHz (1690–2240 MHz, 28%) with mutual couplings of lower than $- {32}$ and $- {26}\;{\text{dB}}$ at the lower and higher frequency bands, respectively. The antenna covers the GSM850/GSM900/GSM1800/GSM1900/UMTS bands for 2G/3G base station applications. Within the two frequency bands, the performance of similar-shaped radiation pattern, low cross-polarization, and stable gain is achieved.