A Tunable Bandpass-to-Bandstop Filter Using Memristor and Varactors

This paper presents a tunable bandpass-to-bandstop filter using memristor and varactors for 5G wireless communications. Memristor has hard switching characteristics and behaves great linearity at high frequencies, thus it can be potentially used as an RF switch to achieve the bandpass-to-bandstop transformation. The proposed filter employs stub-loaded stepped-impedance resonator with four varactors and a memristor. The center frequency of the proposed filter can be flexibly tuned by adjusting varactors. The tuning range almost covers 5G frequency band (3.4 to 3.6 GHz) in both the bandpass and bandstop mode. The simulated results show that return loss is better than 22.18 dB in the bandpass mode and rejection level of bandstop mode is higher than 21.34 dB.