Tunable band-pass filter based on Liquid Crystal

This paper presents a design study of a tunable band-pass filter. The tunability is achieved by using Liquid Crystal (LC) as a tunable dielectric. The respective three-pole filter is designed to have a center frequency of 20GHz. It is shown that the center frequency of the designed filter can be shifted by approx. 2GHz. The device is fabricated using a glass-LC-glass sandwich structure with a total thickness of 600 µm. The lateral dimensions of a single filter structure are 9×4 mm.

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