High Selectivity Wideband Bandpass Filter Based on Transversal Signal-Interaction Concepts and T-Shaped Structure

A high selectivity wideband bandpass filter (BPF) based on transversal signal-interaction concepts and T-shaped structure is proposed in this letter. Two transmission paths with two open coupled lines and a T-shaped structure are used to realize signal transmission from Port 1 to Port 2. A three-order passband with two transmission zeros can be achieved in the proposed filter. One prototype with 3-dB fractional bandwidth of 36.3% (3.3-4.75 GHz) is fabricated for demonstration. Good agreement is observed between simulated and measured performances.