Feed-through capacitance reduction for a micro-resonator with push-pull configuration based on electrical characteristic analysis of resonator with direct drive

In this paper, we propose a feed-through reduction technique for a micro-resonator with a push-pull configuration that is based on the analysis of electrical characteristics of a direct driving micro-resonator. We show that the feed-through capacitance is decreased by reducing the sizes of the driving and sensing electrodes, inserting bias electrodes between them, and by surrounding them with a bias electrode. Using the proposed methods, we succeeded in reducing the feed-through capacitance and improving the performance of the micro-resonator with a push-pull configuration. We propose designs for the push-pull configuration with small electrodes, small electrodes and the insertion of bias electrodes between the driving and sensing electrodes, and surrounding the electrodes with a bias electrode. The feed-through capacitance of the small electrode model is 41.9 fF, an approximately 50% decrease from the general model (90.1 fF). The feed-through capacitance of the model with inserted bias electrodes is 17.9 fF. The feed-through capacitance of the model surrounded with an inserted bias electrode is 10.9 fF. The electrical transmission according to the feed-through capacitance was measured for each model. The efficiency in the electrical transmission is increased from 7.83 dB (the general model) to 8.94 dB (the small electrodes), 9.18 dB (inserting bias electrodes model) and 9.40 dB (surrounded with bias electrode model). We experimentally verified that the feed-through capacitance is decreased by reducing the sizes of the driving and sensing electrodes, inserting bias electrodes, and surrounding the electrodes with bias electrodes. The feed-through capacitance reduction technique would be useful for sensors, such as a micro-resonator requiring high performance, and radio frequency (RF) devices operating at high frequencies.