Design of UWB Monopole Antenna with 5.5/7.5 GHz Enhanced and Controllable Dual Band Rejection Characteristics

This paper presents a printed ultra-wideband (UWB) monopole antenna with enhanced dual-band notch characteristics at 5.5 GHz and 7.5 GHz. As the proposed antenna comprises a quasi-elliptical patch and staircase ground plane with rectangular bevel slots, it is capable of producing much wider impedance bandwidth (2.9 -16 GHz, VSWR ≤ 2). To obtain enhanced rejection at 5.5 GHz, two different λ/2 filters are incorporated. These filters include C shaped slot at the patch and symmetrical pair of Rectangular single complementary split ring resonator (RSCSRR) to the ground plane. Strong rejection at 7.5 GHz has been achieved by employing another combination of λ/2 filters consisting of U shaped slot on the feed line and modified C shaped defective ground structure (DGS). By proper adjustment of the gap between the RSCSRR pair and separation of modified C shaped DGS from the lower periphery of the ground plane, the Quality factor of the notched bands can be easily controlled.