Circularly polarized slot antennas with wideband performance

Circularly polarized (CP) slot antennas exhibiting the wideband performance are studied using L-shaped stub along with microstrip feed-line for dual-band applications. The proposed antennas consist of a wide-slot radiator along with a microstrip feed-line and an L-shaped stub. An L-shaped stub is used to excite the slot radiator for a CP radiation. Various slot-shaped antennas are compared based on CP radiation bandwidth with a fixed slot-shaped perimeter. The hexagonal- and circular-shaped-slot antennas are useful to achieve a wideband CP radiation. The circular-shaped-slot antenna is designed and fabricated for dual-band CP radiation using slit/slot in the L-shaped stub. The circular-slot antenna measured performances are 24% (3.0-3.84 GHz) and 18% (4.3-5.15 GHz) for 3-dB AR bandwidths for the 3.5 and 4.5 GHz bands. The measured gain is 4.0 dBic for 3.5 GHz band and 3.0 dBic for 4.5 GHz band at the boresight.