Design and Fabrication of Efficient Piezo-MEMS Voltage Transformers

RF Voltage transformers operating in one of the ISM frequency bands have recently been demanded in emerging low-power applications, such as wake-up radios in wireless networks, remotely triggered switches, stand-by units in home electronics, etc.. Here we propose the use of two-port S0 Lamb wave resonators (LWR) as passive voltage transformers incorporated into a microsystem for the detection of low amplitude RF signals. LWR transformers based on the technologically simplest single-side IDT architecture are developed with care to impedance matching and voltage gain boosting. Design approaches are discussed in view of the limits imposed by the relatively low electromechanical couplings achievable with the single-side IDT architectures. Finally, 423 MHz LWR transformers with edge-reflectors and tetherless design are designed, fabricated and characterized.