An electronic device includes a substrate, a plurality of conductive patterns, and a tunable element. A plurality of conductive patterns are disposed on the substrate. The tunable element is disposed on at least one conductive pattern in the plurality of conductive patterns and includes a first pad, a second pad, and a third pad. The first pad, the second pad, and the third pad are separated from each other. The first pad and the second pad are overlapped with the at least one conductive pattern in the plurality of conductive patterns. The third pad is disposed between the first pad and the second pad.