Integrated Actuation of Microfluidically Reconfigurable mm-Wave SPST Switches

This article demonstrates the design and performance of a single-pole single-throw (SPST) microfluidically reconfigurable switch. The switch is formed by placing a microfluidic channel over a microstrip line gap discontinuity. A selectively metallized plate located inside the microfluidic channel is repositioned with fluid flow to capacitively load the discontinuity to achieve the RF switching functionality. Different from prior works based on external micropumps, the SPST switch is integrated with a piezoelectric actuator. The switch layout is optimized to obtain a low actuation time. A switch prototype is characterized to exhibit low insertion loss (0.42 dB) at 30 GHz and wide bandwidth (18 GHz). It operates with rise and fall times down to 1.12 ms. It is actuated by three million switching cycles with no performance degradation. To the best of our knowledge, the presented switch exhibits the lowest reconfiguration time, highest operation frequency, and the highest reliability among the microfluidically reconfigurable devices reported in recent literature.