Ultra-compact switchable microstrip band-pass filter-low-pass filter with improved characteristics

A novel, ultra-compact switchable microstrip band-pass filter-low-pass filter (BPF-LPF) showing wide stop band and good attenuation characteristics is proposed in this paper. Both BPF and LPF operation utilizes a common geometrical filter section, and individual filter operation is realized by means of the switches operated in ON or OFF mode. The proposed filter is designed for the dual mode BPF for wireless local area network (5.15-5.35 GHz) application with all four switches in OFF condition and for the LPF at 3 GHz cut-off frequency with all switches in ON condition. The insertion loss (S-21) in the stop band region is below -20 dB extending up to 12 GHz for both the filters. The proposed reconfigurable filter is ultra-compact having the circuit size of only 5.952 mm x 8 mm=47.616 mm(2). The simulation result is validated experimentally. (c) 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:197-201, 2017