A Novel Square Dielectric Resonator Antenna With Two Unequal Inclined Slits for Wideband Circular Polarization

A novel dielectric resonator antenna (DRA) is presented for wideband circular polarization (CP). Two unequal inclined slits are loaded on the diagonal of the square DR to excite a CP mode. The effect of variation of ratio between the length of the slits on the CP and impedance characteristics is studied. The DR is excited by a proper tapered strip, connected to the input microstrip line from one side, and finally matched by a chip resistor from the lateral side. As the key parameters, the position of the excitation and matching lines and the impedance of the chip resistor are carefully optimized to adjust and improve the CP. The proposed configuration offers a relatively compact and easy-to-fabricate feeding network and multiresonant performance providing a 3-dB axial-ratio and impedance bandwidth of about (43-50)% around 3.7 GHz, gain between 4 and 6 dBi. The CP and impedance parameters of the antenna are studied, and reasonable agreement between the measured and simulated results is observed.