Design of Compact Quadruple Inverted-F Antenna With Circular Polarization for GPS Receiver

A compact quadruple inverted-F antenna (QIFA) with right-hand circular polarization for global positioning system (GPS) receiver is presented. The proposed QIFA consists of four spiral-shaped inverted-F antennas fed by a compact multilayered feed network. In order to improve the radiation efficiency of four-port feed antenna like QIFA, we analyze an optimum matching method considering both reflection coefficient at each port and the mutual coupling between ports simultaneously. Experimental results show that QIFA of size 10 x 10 x 12 mm
³
has a 3-dB beamwidth of more than 130
^°
, the peak gain of -1 dBic and the axial ratio under 2 dB.