Edinburgh Napier University

  This paper presents a design for a single-feed, compact, tunable microstrip F- slot antenna capable of achieving high tuning ranges without using any matching networks. An F shaped slot embedded in a patch is used to generate resonant frequencies. The tuning is achieved by applying reverse bias to a single varactor diode integrated across the slot arms of the patch. The tuning does not require any further modification to the patch or feed geometry. The proposed frequency-tuned antenna has been designed to meet the coverage requirements of the DCS, PCS, and UMTS bands. The antenna offers tuning range from 1.7 to 2.15 GHz, with good impedance match in the entire tuning range. Good agreement is obtained between the predicted and measured input return loss, gain and radiation pattern over the tuned frequency range.