Design Of Compact Printed Antenna With Notched Bands For UWB Applications

The features of Ultra-Wideband （UWB） technology brings itself good prospects andbroad applications As one key component of wireless UWB system, the characteristics ofUWB antenna directly affects the entire performance of system. So, it’s importance isself-evident.The paper tries to explore the ultra-wideband antenna notch characteristics throughthe method of current distribution on the antenna surface before the introducing of UWBantennas. And the design should satisfy requirements of the UWB antenna. This paper isanalyzed and discussed of two parts. In the first part, a summarize of the ultra-widebandantenna is discussed and presented. The paper firstly introduces the parameter structure andthe characteristics of notch bands. And then the design requirements of the UWB antenna ispresented and discussed. Based on the theory and method mentioned, a compact UWBantenna and three kinds of UWB antenna with band notched characteristics is discussed inthe second part of the paper.The paper tries to analyze the band notched characteristics by the way of introducingthe surface current of antennas. The last part is the design of antennas, in which part, fourkinds of UWB antennas are designed and discussed. We use the common CPW structure torealize the UWB antenna and gain a compact size in the first design of antenna. For thesecond antenna, we introduced stepped symmetrical L-shaped gap in a ground planeantenna, with a simple way to achieve the ideal notch characteristics; While in the thirdantenna, we try to use a slotted L-shaped symmetry minor ways, and an improved feederU-shaped gap are introduced, and ultimately gain the independent and adjustable notchcharacteristics. For the fourth design of the UWB antenna, the dual band-notchedcharacteristics are obtained by etching a pair of L-shaped slots on the edge of ground planeand introducing two symmetrical L-shaped stubs on the radiating patch. Simulated andmeasured results show that this antenna could obtain UWB characteristics, except doublenotched frequency bands. Moreover, the proposed antenna shows good gain flatness andstable far field radiation patterns.