An Electronically Reconfigurable Single to Dual-Band Bandstop Filter for RFID and Modern Wireless Communication Application

The excessive demand of electronically reconfigurable Band Stop Filter (BSF) for radio frequency identification (RFID) and for reducing Electromagnetic Interference (EMI) for modern wireless communication is highly evident. Thus, a new electronically reconfigurable stub topology-based BSF is proposed. The response of the BSF filter can be switched from single to dual-band. The switching is achieved by a silicon PIN diode (BAP70-03) and a biasing network. When the switch is OFF, it gives a single-band bandstop response with the bandwidth of 1.70GHz - 5.74GHz. When the switch is ON, it offers dual-band bandstop response with the bandwidth of 1.42GHz - 1.59GHz @ 4.82GHz – 5.73GHz, and between both stopbands, the passband of 1.96GHz – 4.56GHz facilitates mobile communication (3G, 4G, and 5G). Validation of the |S| parameter of the proposed reconfigurable filter is carried out using the filter’s transmission line model (TLM) for both the ON and OFF state of the PIN diode. Consequently, even and odd mode impedance is calculated analytically, and a lumped equivalent circuit model of the proposed BSF filter is extracted. The simulation results of the electromagnetic (EM)/distributed model, equivalent lumped circuit model, and measured results of fabricated prototype reconfigurable BSF filter are in good agreement.