Cross-Coupled Bandpass Filter using Microstrip Triangular Open-Loop Resonators

A new cross-coupled planar microwave filter is proposed using coupled microstrip triangular open-loop resonators. The full-wave EM simulator is used to design the triangular resonator and to calculate the coupling coefficients of three basic coupling structures encountered in this type of filter. A four-pole elliptic function filter of this type is designed and fabricated. Measured filter performance is compared with the simulated performance.