Wideband Circular Patch Antenna for Pattern Diversity Application

A low-profile wideband circular patch antenna with pattern diversity is proposed. The TM mode of the patch is excited by two feeding loops with in-phase current, which radiates the broadside beam. The TM mode is excited by another set of feeding loops with antiphase current, which radiates a conical beam. The two modes can operate at an overlapped frequency range. The proposed antenna is fabricated and measured. The measured impedance bandwidth (VSWR <; 2) for the broadside beam is from 1.71 to 2.25 GHz, and for the conical beam is from 1.36 to 2.17 GHz. The measured gains of the broadside beams and conical beams are 8-9.7 dBi and 3.8-6.4 dBi, respectively. The isolation between the two input ports is better than -25 dB. The antenna can be used as a pattern diversity antenna for modern mobile communications.