Shunt capacitive switches based on VO2 metal insulator transition for RF phase shifter applications

Abstract

Abstract-This paper presents a wide-band RF shunt capacitive switch reconfigurable by means of electrically triggered Vanadium Oxide (VO2) phase transition to build a true-time delay (TTD) phase shifter. The concept of VO2-based reconfigurable shunt switch has been explained and experimentally demonstrated by designing, fabricating and characterizing an 819 µm long unit cell. The effect of bias voltage on losses and phase shift has been studied and explained. By triggering the VO2 switch insulator to metal transition (IMT) the total capacitance can be reconfigured from the series of two metal-insulator-metal (MIM) capacitors to a single MIM capacitor. Higher bias voltages are more effective in this reconfiguration and give a higher phase shift. The optimal achievable performance has been shown heating the devices above VO2 IMT temperature. A maximum of 16° per dB loss has been obtained near the design frequency (10 GHz).

A Reconfigurable Inductor Based on Vanadium Dioxide Insulator-to-Metal Transition

“…Although the Q-factor can be evaluated in many ways [10][11], we used Eq. 2, as in [1,[6][7][8], in order to make a coherent comparison. Y21 and Y11 denote the two port admittance parameters while f stands for the frequency.…”

“…In order to overcome the issues, we propose in this letter to use Vanadium Dioxide (VO2) as a tuning element in reconfigurable inductors exploiting its IMT transition: VO2 undergoes an electronic and structural phase transition from an insulator with monoclinic crystalline structure to a metallic rutile phase when heated above 68 °C. This phenomenon has been used lately in various microwave components such as switches [2], [3], transmission lines [4], attenuators [5], phase shifters [6], bandstop filters [7] and for the first time as a reconfigurable inductor [8]. However the inductor in [6], made with two coils This work has been supported by the HORIZON2020 PHASE-CHANGE SWITCH Project (Grant.…”