• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2012.10a
• /
• pp.586-589
• /
• 2012

In this paper, a tunable capacitor like an interdigital one is presented for low-voltage applications. In order to reduce operation voltage by enhancing fringing electric fields, two finger-patterned electrodes are vertically separated by employing a multi-layer thin film dielectric of a para-/ferro-/para-electrics without spacing between electrodes. The proposed tunable capacitor was fabricated on a quartz wafer and its characteristics are analyzed in terms of effective capacitance and tunability with a function of applied voltages, compared to the conventional interdigital capacitor (IDC). At 8V and 2 GHz, the proposed tunable capacitor shows the tunability of 18 % that is 10.3 % higher than that of the compared one.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2002.11a
• /
• pp.370-374
• /
• 2002

This paper describes the design and fabrication of distributed analog phase shifter circuit. The phase shifter consist of coplanar waveguide(CPW) lines that are periodically loaded with voltage tunable (Ba,Sr)TiO$_3$ thin film interdigital(IDT) capacitors deposited by the pulsed laser deposition(PLD) on (001) MgO single crystals. The phase velocity on these IDT loaded CPW lines is a function of applied bias voltage, thus resulting in analog phase shifting circuits. The measured differential phase shift is 48$^{\circ}$ and the insertion loss decreases from -5㏈ to -3㏈ with increasing bias voltage from 0 to 40 V at 100㎐.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.16 no.3 s.94
• /
• pp.253-259
• /
• 2005

In this paper, BaSrTiO$_{3}$(BST) thin film tunable interdigital capacitor using low cost silicon substrate instead of expensive single-crystalline substrate is presented. The tunable capacitor in which BST thin film is deposited by PLD has operation frequency and applied bias up to 4 GHz and 50 V, respectively. The maximum tunability in capacitance is found to be 30$\%$, for an applied field of 5 kV/cm at a bias of 50 V. Therefore, it has been shown that the BST microwave tunable capacitor can be integrated onto Si substrate.