Microstrip Dual-Band Bandpass Filter With Wide Bandwidth Using Paper Substrate

This work presents the design and analysis of a novel dual-wideband bandpass filter (BPF) using the transversal filtering section (TFS), coupled lines (CLs), and stepped impedance stubs (SISs). Initially, a dual-band BPF employing TFS and CLs is designed. To enhance the bandwidth and selectivity, SIS units and quarter wavelength transmission lines are attached at the input and output ports. This novel filter's frequency response has six transmission zeros in the stopband and four transmission poles in each passband. A prototype with center frequencies of 1.17 and 2.4 GHz is realized on a biodegradable substrate and tested. The tested and simulated results are in high congruence, validating the proposed design circuit and theory.