Compact Linearly and Circularly Polarized Unidirectional Dielectric Resonator Antennas

The linearly polarized (LP) and circularly polarized (CP) unidirectional dielectric resonator (DR) antennas (DRAs) with compact ground planes are investigated. Both designs make use of the broadside DR HEM11 delta mode to obtain the required equivalent magnetic dipoles. The required electric dipoles are provided by the currents on the small ground planes. To demonstrate the idea, both LP and CP unidirectional DRAs operating at 2.4 GHz were designed, fabricated, and tested. Reasonable agreement between the measured and simulated results is observed. It was found that the front-to-back ratio (FTBR) of the LP design is more than 15 dB over the frequency range 2.30-2.55 GHz (10.1% bandwidth). For the CP design, the FTBR is over 15 dB across the frequency range 2.40-2.55 GHz (6.1% bandwidth).