Low-Profile and Wide-Beamwidth Dual-Polarized Distributed Microstrip Antenna

A low-profile and wide-beamwidth dual-polarized distributed microstrip antenna is presented in this paper. Four isolated micro patches are proposed as the radiation components and are excited by a compact differential-fed network. The micro patches in two diagonals determine the operating frequency bands of the two polarizations, respectively. By increasing the distances between the micro patches, the beamwidth in E plane can be broadened. Shorting poles between the patches and the ground plane are used to achieve good impedance matching. Compact dual-polarized differential-fed networks are also studied and compared with achieve the best antenna performance. To validate the proposed method, a wide-beamwith dual-polarized distributed microstrip antenna, whose dual polarizations operate at 2 and 2.2 GHz, respectively, is manufactured and measured. The external dimensions of the antenna is 70mmx10 mm (0.49λ x 0.07λ). The experimental results agree well with the simulated ones. The 3dB beamwidths in E planes reach 116° and 115°, and the gains are 5.15 and 5.5 dB for two polarizations, respectively. Meanwhile, the cross polarizations are less than -26.2 and -27.8 dB. In addition, the impedance bandwidths of 9.2% and 9.9% for VSWR≤2 are achieved, and the port isolation is greater than 25.4 dB in the bands.