| Title |
High-Q Micromechanical Digital-to-Analog Variable Capacitors Using Parallel Digital Actuator Array |
| Authors |
한원(Han, Won) ; 조영호(Cho, Young-Ho) |
| Keywords |
Digital-to-Analog actuators ; Variable capacitors ; Q factor ; Precision |
| Abstract |
We present a micromechanical digital-to-analog (DA) variable capacitor using a parallel digital actuator array, capable of accomplishing high-Q tuning. The present DA variable capacitor uses a parallel interconnection of digital actuators, thus achieving a low resistive structure. Based on the criteria for capacitance range (0.348~1.932 pF) and the actuation voltage (25 V), the present parallel DA variable capacitor is estimated to have a quality factor 2.0 times higher than the previous serial-parallel DA variable capacitor. In the experimental study, the parallel DA variable capacitor changes the total capacitance from 2.268 to 3.973 pF (0.5 GHz), 2.384 to 4.197 pF (1.0 GHz), and 2.773 to 4.826 pF (2.5 GHz), thus achieving tuning ratios of 75.2%, 76.1%, and 74.0%, respectively. The capacitance precisions are measured to be 6.16pm4.24 fF (0.5 GHz), 7.42pm5.48 fF (1.0 GHz), and 9.56pm5.63 fF (2.5 GHz). The parallel DA variable capacitor shows the total resistance of 2.97pm0.29 {Ω} (0.5 GHz), 3.01pm0.42 {Ω} (1.0 GHz), and 4.32pm0.66 {Ω} (2.5 GHz), resulting in high quality factors which are measured to be 33.7pm7.8 (0.5 GHz), 18.5pm4.9 (1.0 GHz), and 4.3pm1.4 (2.5 GHz) for large capacitance values (2.268~4.826 pF). We experimentally verify the high-Q tuning capability of the present parallel DA variable capacitor, while achieving high-precision capacitance adjustments. |