Feed configurations of CPW fed DRA

A comparison of CPW (coplanar waveguide) feed configurations for the DRA (dielectric resonator antenna) is presented with the goal of optimizing the feed geometry with respect to its topology and radiation performance. Characteristics of CPW capacitive and square loop feeds are discussed. It is observed that the space requirements of the feed and the radiation pattern are dependent on the feed configuration. It is important that the CPW feed is completely covered by the DRA. The square loop feed has the particularly attractive feature of very small area compared to other feeds, making it possible to design it on low permittivity substrates and totally contained within the DRA area. This also leads to reduced excitation of surface waves in the CPW substrate. The H-plane cross-pol level for the square loop feed is much better compared to the capacitive feed due to its completely symmetric nature. Also, it is possible to excite the capacitive slot over the entire slot length or primarily over the CPW trace region by only changing the slot length, thus producing dual-resonance. Fabrication and measurements on the proposed feed configurations are currently being conducted.