Resonator cross-coupled bandpass filters with spurious suppression

A direct and cross cascade of coupled microwave filter using an open loop resonator are proposed. This paper presents theirs efficiency are enhancement by employing the quadruply-step impedance transmission lines compensated parallel-coupled line. The spurious responses are occurred. Simple empirical models are designed and fabricated to solve this problems, the directivity enhanced parallel-coupler should be employed. The measured results are in good agreement with the simulated prediction and the operating frequency is 0.9GHz.