Design of a compact broad band-pass filter using parallel coupled structure

In this paper, a new BPF with PCL structure has been discussed. The conventional BPF with PCL structure has limitation in 20% bandwidth and it cannot be easily realized due to very narrow coupling gaps when wide bandwidth is required. The new PCL BPF structure has two long coupling sections (J-inverters) and extra capacitive coupling gap between upper lambda_epsiv/4 lines. That is why this new structure can provide wide bandwidth. In this paper, we analyzed this new structure using ABCD matrix and applied for synthesizing the broad BPF design. Also, this structure has small size compared with the conventional one. This new broadband PCL BPF can be applied for microwave system or ITS (intelligent transport system) application.