A Miniaturized Microfluidically Reconfigurable Coplanar Waveguide Bandpass Filter With Maximum Power Handling of 10 Watts

In this paper, a microfluidically reconfigurable coplanar waveguide (CPW) filter is presented with a tuning range of $\sim$ 1.6:1 and four different states. The passband frequency of the filter is changed based on employing the capacitive loading effect of a liquid metal placed on top of each CPW resonator using three parallel micro-channels. In addition, because of the loading effect of the metal bridges, miniaturization by a factor of 40% is achieved. The filter is digitally tuned from 3.4 to 5.5 GHz with an insertion loss of less than 5.0 dB and a relative bandwidth of 5 $\pm$ 0.35%. The RF power-handling capability of the filter is characterized using a customized measurement setup. It is observed that the filter can be used for input RF powers of up to $\sim$ 20 W for short-duration excitation conditions and 10 W for high-average-power excitation conditions. The filter is realized using common printed circuit board technology and a polydimethylsiloxane structure. Design methodology, simulation, and measurement results of the filter prototype are presented.