Abstract: “A new frequency agile BST varactor loaded stacked circular microstrip antenna is presented. The antenna is analysed using extended cavity model. One of two bands of antenna is tunable with the help of BST varactor. The upper band is useful for WiMAX and lower band for other wireless communication systems. Various antenna parameters like return loss, resonant frequency, frequency agility etc. have been investigated. The simulated results agree well with the numerical data. A frequency agility of 60.64% is achieved, which is better than simple Varactor diode loaded antenna. Lowest resonant frequency of 0.866GHz is obtainable that shows a significant physical area reduction.”

Keywords: stacked antenna, gain, bandwidth.