Frequency Agility of Broadband Antennas Integrated With a Reconfigurable RF Impedance Tuner

This letter demonstrate the frequency agility that can be achieved when an broadband antenna is integrated with a reconfigurable RF tuner as na impedance matching circuit. The reconfigurable tuner uses a microstrip loaded line structure with four stubs that are each terminated by a varactor diode. The spectral response can be varied by changing the capacitance of the diodes. Input impedance data obtained from measurements on commercially available antennas were used in an agilent advanced design system (ADS) model of the four-stub tuner. The results show that adding the reconfigurable tuner can facilitate excellent frequency agility of the return loss of the broadband antenna over several narrow frequency subbands