In this paper, the effect of the finger-patterned electrodes on a tunability of tunable capacitors has been investigated. Two tunable capacitors with finger-pattern electrodes, a metal-insulator-metal (MIM) capacitor with the finger-pattern metal on the top electrode and a sandwich inter-digital capacitor (IDC) embedding a dielectric layer between finger-pattern metal layers, are fabricated using a low-loss and high-tunability para/ferroelectric multi-layer thin film dielectrics and analyzed in terms of S_(11) effective capacitance and tunability compared to the conventional MIM capacitor. At 25 V and 2 GHz, the maximum tunability of the finger-patterned capacitor is 38% that is 5.8% higher value than that of the convention one. At the same DC voltage of 8 V, the novel sandwich IDC shows the tunability of 18% which over 12% higher than that of the convention MIM one. These results demonstrate that high-fringe electric fields induced due to the finger-pattern electrodes improve their tunability.
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