Researches On The Ultra-wideband Character Of Miniaturized Antennas With Band-notched Property

Ultra-wideband (UWB) wireless communication technology brings about broad attention due to its merits such as high-speed, low-loss, low-cost and outstanding time-domain fidelity, indicating good prospects. UWB antennas play an important role in the UWB communication system. Miniaturized UWB antennas are convenient to be integrated in the engineering applications and widely used in radar and wireless communication systems. The performances of antennas have a direct impact on the quality of the communication system, so it is significant to design practical miniaturized UWB antenna. The dissertation mainly introduces the studies on the UWB dielectric resonator antenna and the UWB plane monopole antennas, furthermore, some researches on the band-notched UWB antenna for wireless local area network (WLAN) application are also presented. The main contents are as follows:1. An improved UWB dielectric resonator antenna, based on a previous design, is designed by utilizing the air chamber to change the shape of the dielectric resonator. Simulation results show that the operating band ranges from2.5GHz to11GHz, the relative bandwidth is126%, which is greatly broaden compared with4.6-6GHz of the original structure. The maximum gain gets4.86dB, which has also improved.2. By changing the grounds and radiation patches and loading L-shaped and U-shaped gaps on the patches, two band-notched UWB planar monopole antennas are designed. Measured results of the antennas are consistent with the simulation results, and the antennas are compatible with WLAN network.The coplanar waveguide fed planar monopole antenna which is etched on a30×30×0.8mm3FR4board achieves a3.0-12.1GHz operation band by curving the ground and radiation patch. The antenna achieves good radiation patterns and a5.32dB maximum gain. The antenna gets band-notched during the band5.1-5.9GHz for WLAN applications by loading a couple of L-shaped gaps.By changing the shapes of the patch and the ground, the micro-strip line fed planar monopole antenna etched on a32×52×1.59mm3FR4plate gets a3-14GHz operation band, namely129%relative bandwidth, and a4.47dB maximum gain. The antenna is also band-notched during the band5.1-5.9GHz for WLAN applications by loading a couple of U-shaped gaps.