Wideband circular polarization reconfigurable slot antenna with compact size for GNSS

A wideband circular polarization-reconfigurable (CPR) slot antenna with compact size for Global Navigation Satellite System (GNSS) applications is presented. The antenna consists of a rectangular-loop slot, a microstrip feed line, a Wilkinson power divider, a 90°-phase shifter, a double-pole double-throw (DPDT) switch, and two L-shaped feeding stubs. For size reduction, four T-shaped stubs are symmetrically placed inside the rectangular-loop slot. Wideband operation of the 90°-phase shifter is constructed using a microstrip line and a lumped-element composite right/left-handed transmission-line (LE-CRLH TL). The input signal is split into two signals with equal amplitude and 90°-phase difference by the Wilkinson power divider and the 90°-phase shifter, and then fed to the corresponding L-shaped feeding stubs. The DC control voltages to the DPDT switch determine if the antenna generates a right-handed or left-handed CP signal. Simulated results show that the proposed antenna has a bandwidth of 1.14–1.65 GHz for 3-dB gain variation.