Frequency reconfigurable patch antenna with defected ground structure using varactor diodes

This paper presents an approach that combines two methods for reducing the size of a patch antenna and obtaining a wide tunability frequency range. The addition of a slot in the ground plan helps to shift down the basic frequency of the patch from 7.273 GHz to 4.267 GHz without modifying the basic geometry of the antenna. By modifying the varactor values, a series of successive bands are obtained, ranging from 4.65 GHz to 6.18 GHz. Accurate simulations are performed by using S-Parameter varactor data files. The patch antenna is suitable for U-NII band applications.