RF MEMS switch integrated on printed circuit board with metallic membrane first sequence and transferring

This letter reports, for the first time, on RF MEMS switches integrated on flexible printed circuit boards (i.e., FR-4) using transfer technology. The devices were first processed on Si-substrate using a modified MEMS sequence and subsequently transferred onto an FR-4 substrate by thermal compressive bonding, mechanical grinding, and wet removal of silicon. The switches were demonstrated with flat metal membrane (top electrode), precisely controlled gap between the membrane and bottom electrode, low insertion loss (≤ 0.15 dB at 20 GHz), and high isolation (∼ 21 dB at 20 GHz). This technology shows the potential to monolithically integrate RF MEMS components with other RF devices on organic substrate for RF system implementation.