Realization of SIW Switches With Integration of VO₂-Coated Flexible Polymers Onto PCBs

This work proposes a dual-faceted innovation for developing efficient substrate-integrated waveguide (SIW) switches. First, we propose, develop, and demonstrate a novel SIW switch based on vanadium oxide (VO2), leveraging the unique metal-to-insulator transition (MIT) properties of VO2 for the first time. Second, we propose a low-cost and effective method for integrating thin-film VO2 into printed circuit board (PCB) circuits, combining the advantages of both technologies. We have employed thin-film VO2 deposited on flexible polymer sheets, which are both economical and exhibit high RF performance. These flexible switchable sheets are affixed on PCB SIW to enable reconfigurability and switching. The developed SIW switches exhibit remarkable performance characteristics. We demonstrate single-pole single-throw (SPST) SIW switches in two configurations, achieving a low insertion loss of 0.6 dB and an isolation level better than 20 dB across the 9–14-GHz frequency range. In addition, we propose and demonstrate a single-pole double-throw (SPDT) SIW switch, achieving an insertion loss of less than 1.0 dB and isolation better than 15 dB within the same frequency band. All measurements show excellent agreement with simulations, validating the proposed methodology and the theoretical foundation of this work.