A capacitively loaded antenna for use in mobile handsets

A tuneable slotted patch antenna design is presented and verified for use in the DCS, PCS and UMTS bands. The tuning circuit consists of two varactor diodes, with some passive components, and is integrated fully with the radiator patch, with the varactors occupying different locations over the slot. The tuning does not require any further modification to the patch or feed geometry. Good agreement is observed between the predicted and observed impedance bandwidth, return loss, gain and radiation pattern, throughout the range 1.70 GHz-2.05 GHz.