Use of dielectric resonator for multi-function applications in microwave circuits and antennas

The concept of multi-functional operation using a single dielectric resonator for radiation, oscillation and filtering purposes is discussed in this paper. Different design realizations are presented to investigate and prove the claimed concept. A dual mode operation for oscillation and radiation characteristics using single dielectric resonator enclosed by modified rectangular cavity has been developed where high non-radiating unloaded quality factor of 2700 at 2.54 GHz and omni-directional radiation patterns with radiation bandwidth of 5% around 3.31 GHz were achieved simultaneously. Also, a dual-band antenna design with two different radiation patterns is achieved with a broadside circularly-polarized pattern with 7% bandwidth and a vertically polarized omni-directional pattern with 17% bandwidth are obtained, simultaneously. The axial ratio was measured to be 1.3 dB and front-to-back ratio was found to be 15 dB. A design suitable for both GPS (Global Positioning System) and WLAN (wireless local area network) applications is suggested. Finally, a single dielectric resonator is used for a triple mode operation in filtering and dual band radiation purposes. A high unloaded quality factor over 2300 at 2.43 GHz is obtained simultaneously with both broadside and omni-directional radiation patterns of 7% and 8% bandwidths around 2.47 and 3.36 GHz, respectively. Series of parametric studies are devoted to tune the different mode´s operating frequency and to enhance the filter insertion loss while adjusting a sharp filtering skirt behavior. The outlined design configurations were simulated, built and tested. Experimental work and measured scattering parameters and far field radiation patterns were all compared with the simulated results for further verification.