Resonator bandpass filter using the parallel coupled wiggly line for supurious suppression

This paper describes the resonator bandpass filter design using the non-uniform parallel coupled “wiggly-line” technique. The proposed resonator is consisted of three sections quarter wavelength coupler and each of sections has perturbation and Z₀ connected in the end of each ports. This resonator can reduce the spurious response at 2f₀ and 3f₀ by its structure. The directivity enhanced parallel-coupler should be employed to solve this problem. The experimental results and designs of all type are 0.9 GHz to implement bandpass filters. There were evidently shown the second and third spurious response suppression improvement. Both the theoretical and experimental performance is presented.