Switchable bandstop to bandpass filter using parallel-coupled resonator

• Main Authors: Zahari, M.K., Ahmad, B.H., Wong, P.W., Shairi, N.A.
• Format: Article
• Published: Institute of Electrical and Electronics Engineers Inc. 2018
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044742292&doi=10.1109%2fAPMC.2017.8251494&partnerID=40&md5=cc431ed4e075e78747dc7ab0e8ec86a8; http://eprints.utp.edu.my/21856/

A new prototype of switchable bandstop to bandpass filter was designed and fabricated by using parallel-coupled lossy resonator. The lossy resonator topology was used to partially compensate for the losses. The fundamentals of having two lossy Q resonator structures are that it exhibits a bandpass filter, where the parallel-coupled resonator is disconnected with the λ/4 wavelength. PIN diodes are used to change the filter's response. In the experiments, the filter exhibited a high-Q bandstop response when the PIN diodes were switched 'ON' with an operating frequency of 2.4GHz, an attenuation of 75dB and return loss S11 > 20dB. The lossy bandpass filter was produced when the PIN diodes were switched 'OFF'. The theoretical analysis together with the fabrication results were presented in this paper. © 2017 IEEE.