Electrical engineering

Physics

Microstrip

Band-pass filter

Bandwidth (computing)

Wideband

Low-pass filter

Insertion loss

Band-stop filter

Optics

Filter (signal processing)

Engineering

Multi-band device

Prototype filter

Antenna (radio)

Materials science

Electronic engineering

Fractional bandwidth

Passband

Optoelectronics

Telecommunications

IEEE Microwave and Wireless Components Letters

A compact multifunctional switchable filter based on parallel-coupled lines with three different filtering functions is presented in this letter. By using p-i-n switches to connect or disconnect microstrip line and shorted coupled lines, three different modes, i.e., wideband bandpass filter (BPF), bandstop filter (BSF), and dual-band BPF, can be realized. For demonstration, the switchable filter prototype is designed and fabricated. For the wideband BPF mode, the measured 3-dB fractional bandwidth is about 53.1% (1.41-2.43 GHz) with the measured insertion loss of 0.9 dB. For the BSF mode, the measured 10-dB fractional bandwidth is about 30.2% (1.63-2.21 GHz) with in-band suppression level of over 15.5 dB. For the dual-band BPF mode, the measured 3-dB bandwidths of the two passbands are around 3.8% and 2.7%, respectively.

Multifunctional Switchable Filter Using Coupled-Line Structure