Tuning range enhancement of a frequency-agile tri-band slot antenna

Abstract

A low-profile tri-band slot antenna with enhanced tuning range is presented in this paper. Tri-band frequency agility is obtained using three varactor-loaded slots on a planar structure. The tuning range of the proposed antenna is enhanced by suppressing the higher-order resonance modes, especially by controlling the surface currents and creating a fictitious ground on the antenna. Following full-wave simulations, a prototype was developed and measured to validate the concept. Results show a tuning range from 600MHz to 3300MHz, which is a 600 MHz increase in the overall tuning range than previously reported