A Novel C-Band Bandpass Microstrip Filter Using Stubline Coupling

This paper proposes a stubline coupling microstrip bandpass filter based on uniform impedance resonators. Additional coupling components are employed in the circuit to strengthen the coupling. In this way, the filters, which resonators all have the same orientation, can apply to frequency bands higher than VHF and UHF bands. A 5th-order filter prototype with a targeted central frequency of 7.17 GHz, a center loss of 0.88 dB, and a bandpass VSWR of 1.32 is proposed, simulated, and manufactured. A good agreement is demonstrated between the results of measurement and simulation.