Antenna device

摘要

An antenna device having a high gain is presented. The device includes an antenna element, a variable capacitor disposed closely to the antenna element and connected to the antenna element in series or parallel to form a resonance circuit, a tuning voltage supply terminal for supplying a tuning voltage for varying a capacitance of the variable capacitor, and an signal power terminal capable of at least one of sending a signal power to the resonance circuit and receiving a signal power from the resonance circuit.