Dual-mode microstrip triangular patch resonators and filters

Dual-mode operation of microstrip triangular patch resonators has been investigated. It has been found theoretically that the dual modes can result from the rotation and superposition of a fundamental mode. The characteristics of the dual modes and their mode splitting are described. The application of this new type of dual mode microstrip patch resonator in the design of microwave planar filters is presented. A two-pole filter and one four-pole filter of this type are demonstrated for the first time. Both theoretical and experimental results are presented. Advantages of using this type of filter are not only its lower loss and higher power handling capability, but also its compact size and natural circuit topology for implementing filters.