Wideband balanced BPF design for MB-OFDM applications

In this article, a new wideband balanced bandpass filter is designed using coupled coplanar waveguide (CPW) stepped-impedance resonators (SIRs) that are fed by microstrip lines at the input and the output ports. For differential-mode (DM) operation, the BPF circuit exhibits wideband bandpass characteristic that meets the requirement of the OFDM group-B bandwidth specification (4.752-6.072 GHz). The minimum passband insertion loss is only 0.43 dB. For common-mode (CM) operation, the insertion loss of larger than 20 dB over 1-10 GHz frequency range is achieved. The occupied area of the fabricated BPF circuit is 9.9 × 10.5 mm
²
. Good agreement was observed between simulated and measured results.