A Fully Printed Switch Based on VO2 Ink for Reconfigurable RF Components

Recently, vanadium dioxide (VO
₂
) has emerged as an attractive phase change material which can be used for reconfigurable or switchable RF components. However, at present, VO
₂
is deposited by expensive and complex thin film microfabrication techniques. With the surge in low cost, additively manufactured or printed components, it will be beneficial to print phase change materials or switches as well. The issue is there are no such functional inks available in the market. In this work, we present, for the first time VO
₂
based ink that changes its conductive properties based on temperature. Precisely, it displays insulating properties at room temperature (resistance of ~ 5KΩ in the off-state), but becomes conductive when heated around 70°C (resistance of ~ 10Ω in the on-state). Based on this VO
₂
ink and a custom silver-organo-complex (SOC) ink, we demonstrate a fully printed thermally controlled RF switch in this work. In a CPW based shunt configuration, the fully printed switch provides more than 15 dBs of isolation (in the off state) and a 0.5-2 dB of insertion loss (in the on state) from 100 MHz to 30 GHz frequency band. To demonstrate its application, a fully printed frequency reconfigurable planar inverted F antenna (PIFA) has also been demonstrated in this work.