A pattern diversity antenna with six input ports

A wideband antenna with conical radiation is first studied in this article. The antenna has the advantages of low profile and simple structure, and it can provide a stable radiation pattern within an impedance bandwidth of about 108%. Then, five radiating elements, including four dipole antennas and one ring slot antenna, are excited from the wideband antenna structure, forming a six-port antenna. The integrated antenna at 3.5 GHz band can offer a broadside pattern with 9.3 dBi gain, a conical pattern with 4.3 dBi gain, and four symmetrical endfire patterns with 6.4 dBi gain. The design process of the integrated antenna is explained in details, and a prototype is fabricated. The experimental results indicate that the operation bandwidth of the pattern diversity antenna is about 14%, and the isolation between input ports is lower than −16 dB within the bandwidth. Simulated results also validate the experiments.