An impedance tuning system, especially for a cellular telephone system. The system can be used to match the impedance of an antenna element with that of an output stage of a transmitter driving the antenna element. The system includes a piezo capacitor in parallel with the magnetostrictive inductor to form an LC circuit. A voltage controller applies a voltage bias signal to the piezo capacitor and a current controller applies a current bias signal to the inductor. A primary controller monitors the frequency of the output signal from the transmitter and controls the voltage and current controllers as needed to alter the impedance of the system as needed to match the impedance of the antenna element with that of the output stage of the transmitter. In an alternative form an ultrasonic sensor is provided.