Memristor based planar tunable RF circuits

Memristors have been recently proposed as an alternative to incorporate switching along with traditional CMOS circuits. Adaptive impedance and frequency tuning are an essential and challenging aspect in communication system design. To enable both, a matching network based on switchable capacitors with fixed inductors is proposed in this paper where the switching is done by memristive switches. This paper analyzes the operation of memristors as a switch and a matching network based on memristors which adaptively tunes with impedance and frequency. With three capacitor banks of each 0.5 pF resolution and two fixed inductors, matching for antenna impedance ranging from 20 to 200Ohms and for frequencies ranging from 0.9 to 3.2GHz is reported. Thereafter, an adaptive planar band-pass filter is implemented on CMOS technology with two metal layers. This adaptive frequency tunable band-pass filter uses a π network with resonator tanks in both arms that operates at 2.45 GHz. It is tunable from 2.8GHz to 7.625GHz range. This tunability is achieved using tunable spiral inductor based on memristive switches. The proposed filter layout is implemented and simulated in ANSYS Designer. The initialization and the programming circuitry to enable adaptive switching of the memristive devices has to be addressed. Since RF memristive devices are not commercially available, circuit level simulations are done as a proof of concept to validate the expected results.