Phased antenna arrays based on non-volatile resistive switches

The authors propose a phased patch-antenna array working in the X-band (i.e. 8-12 GHz), in which the beam-steering is obtained by means of two-terminal non-volatile resistive switches (or memristors). These novel components have a simple design and a tunable resistance (suitable for electromagnetic matching), and could replace other volatile switching-type devices (such as PIN diodes, MEMS, etc.), providing good radiofrequency (RF) performance and low-power consumption. They also offer the advantage of non-volatility state, i.e. the controlling signals do not need to be applied continuously, which entails a decrease of the power consumption and a reduction of antenna's sensitivity to power outages. The paper models a simple non-volatile resistive switch working in the microwave and millimetre frequency bands, then simulates, based on these switches, a frequency-tunable dipole antenna and a double patch-antenna array with beam steering capabilities. The authors obtained a multi-resonant array, which exhibits a maximum steering angle of ±28°. They also report the fabrication and characterisation of a resistive switch, based on TiO 2-x that shows promising performance for high endurance and retention, with low insertion loss and high isolation. The results of this study represent the starting point for a new family of microwave tunable devices.