A Simple and Compact CPW-Fed UWB Antenna with WLAN Band Rejection

A new and simple ultra wide band (UWB) antenna fed by a coplanar waveguide (CPW) with notched bands at 5.8 GHz is presented in this paper. The physical dimension of this antenna is 17.5 x 17.5 mm(2) which is considered as one of the smallest UWB antennas with band notched characteristics in the literature. The notched frequency band is created by cutting an elliptical slot of radii a and b and inserting a resonator stub in the radiating patch. The lengths of these radii and stub are used to adjust the centre notched frequency and the rejection band. The fabricated antenna has a broad bandwidth ranging from 3 to 15.2 GHz (based on return loss < -10 dB) with controllable notched band for WLAN applications. The experimental radiation patters are nearly omnidirectional and stable over the entire operating bandwidth in the H-plane and nearly bidirectional with two nulls in the E-plane. The very compact size and the good electromagnetic property of this proposed antenna makes it a good candidate to be integrated into portable devices for UWB systems.