Analysis And Desigen Of Band-notched Uwb Antenna

With the continuous progress of society,people are demand for higher communication speed and communication benefits.Ultra wideband communication technology has many advantages,such as high speed,low power consumption and high stability,which satisfies the contemporary people's pursuit of high-quality communication effect.The bandwidth of the UWB communication system is 3.1?10.6GHz(7.5GHz).However,there are also some narrowband communication systems such as WiMAX(3.3?3.8GHz),WLAN(5.15?5.825GHz),and X band downlink frequency band(7.25?7.75GHz)in satellite communications.In order to avoid the interference of these narrow band systems to UWB systems,similarly,taking into account the need of miniaturization and integration,the study of band-notched UWB antenna has become a hot topic in recent years.The main purpose of this paper is to design and implement UWB antennas that can be applied to UWB communication systems.Therefore,the UWB antenna should first meet the bandwidth requirements of UWB communication,and also meet the requirements of the UWB antenna for the gain and radiation direction.At the same time,in order to avoid interference with the narrowband system in the UWB band,the UWB antenna can achieve the notch characteristics of the narrowband frequency band by loading the gap structure on the surface and the floor of the antenna.In this paper,the electromagnetic simulation software HFSS is used to simulate and optimize the designed UWB antenna.The specific research work includes:(1)Two small planar monopole UWB antennas have been designed.A microstrip line feed is used,the radiation unit is hexagonal structure,and the grounding part is a partial grounding structure.The antenna bandwidth is expanded by slotting on the ground and increasing impedance transformation line.The bandwidth of the antenna is 3.0?11.6GHz,and the relative bandwidth is 117.8%.The overall size of the antenna is 35 x 30mm2.The other one uses CPW feed and rectangle radiation patch.The antenna bandwidth is expanded by the way of cutting the patch and the floor.The bandwidth is 2.15?13.1 GHz and the relative bandwidth is 143.6%.The overall size of the antenna is 40 x 30mm2.(2)On the basis of the two UWB Antennas,the dual-and three band-notched UWB antennas are realized by combining the antenna radiation patch and the etching gap on the floor.Among them,the inverted U-shaped and C-shaped cracks are etched on the UWB antenna patch fed by the CPW,and the double trapping characteristics in the 3.0?3.8GHz and 5.15?5.84GHz bands are achieved.In the UWB antenna fed by microstrip line,the CSRR resonant ring is loaded on the patch,the symmetrical J gap is etched on the floor and the spiral slot is etched on the feeder.The three trapping characteristics of the band in the 3.22?3.97GHz,4.94-5.84GHz and 7.25?7.86GHz bands are realized.The gain of the designed antenna in the notch frequency range can be rapidly reduced to less than-4dB,while the other band gain is above 2dB.(3)The four antennas are fabricated and the antenna performance is tested.The accuracy and feasibility of the design are verified by comparing the antenna measurement results and simulation results.