Variable filter element, variable filter module and fabrication method thereof

摘要

A variable filter element and a variable filter module suitable for decreasing the drive voltage are provided. The variable filter element includes a substrate (10), two ground lines (22) and a signal line (21) between the ground lines, where these lines are disposed to extend in parallel on the substrate. The filter element further includes movable capacitor electrodes (24) which bridge between the ground lines and have portions facing the signal line, drive electrodes (25) which are located between the signal line and the ground lines and generate electrostatic attraction with the movable capacitor electrodes, and a ground line (12a), which is disposed in the substrate, has a portion facing the signal line, and is electrically connected with the ground. The variable capacitor electrodes and the ground line constitute ground interconnection portions, and the signal line and ground interconnection portion constitute a distributed constant transmission line.