Creating Band-Notched Characteristic for Compact UWB Antennas

William SW Cheung, PhD, Associate Professor
Department of Electrical & Electronic Engineering, The University of Hong Kong


Since the US-FCC allocated the frequency band of 3.1-10.6 GHz for Ultra-wideband (UWB) communication systems in 2002, studies on UWB technologies have been widely conducted in both the commercial and academic domains. In most UWB applications such as PCs, high-definition TVs and digital cameras etc., compact and low cost UWB antennas with non-dispersive, omnidirectional radiation pattern with relatively uniform gain are desirable. Planar antennas with the advantages of low-profile, ease fabrication on printed circuits board, and ease integration with other RF components, are more favorable to the traditional 3-D antennas for compact UWB applications.

UWB communication systems operating in such a wide frequency band could easily be affected by the nearby communication systems such as the IEEE 802.11a WLAN from 5.15 GHz to 5.825 GHz in the US. The interference levels emitted by the WLAN systems can be suppressed by using band-stop filters, but this will increase the cost and system complexity and require more space when integrated with other microwave circuits. One possible solution to this problem is to design the UWB antennas with band-notched characteristics. Different design methods have been proposed to implement the band-notched characteristic for UWB planar monopole antennas. However, for compact UWB antennas, it is difficult to accommodate the large-size half or quarter wavelength resonators.

In this talk, we propose to use meandered ground stubs to realize a multiple-band-notched characteristic for a compact UWB monopole antenna. We present the simulation and measurement results using the computer simulation tool CST MWS and the Satimo Starlab system, respectively.