Transmission line filter with tunable capacitor

摘要

A tunable filter design. The filter is implemented using transmission line sections as inductive and capacitive components. At least one capacitive component is a tunable capacitor. In some implementations, the tunable capacitor may be an interdigitated array of finger elements arranged so that the spacing between fingers may be adjusted. The design has a number of advantages including high capacitance for a given circuit area, small area for a given desired capacitance, mechanical stability, high self resonance frequency, and high quality factor.

主权项

1. A tunable filter apparatus comprising:
at least one fixed capacitive element including a first transmission line section disposed adjacent a first dielectric material section having a dielectric constant; at least one fixed inductive element including a second transmission line section disposed adjacent a second dielectric material section having a dielectric constant; and at least one interdigitated capacitive element including at least a first main body and two or more fingers extending from the first main body, the two or more fingers configured as an array having at least two rows and at least two columns.