Design Of The Ultra-Wideband And Notched-Band Planar Antenna

At present,the ultra-wideband(UWB)communication technology is developing rapidly.The research on ultra-wideband antennas has become an important development direction in the field of antennas and has received widespread attention.Researchers have studied various types of ultra wideband antennas.Along with the miniaturization development of communication equipments,planar microstrip antennas have gradually attracted the attention of the industry due to low cost,easy design and manufacture,and low profile.In addition,the UWB frequency band contains other narrowband communication frequency bands,such as satellite uplink/downlink frequency band and Wi MAX(Global Interconnection Access)frequency band.Therefore,UWB system is inevitable to be affected by the interference from these frequency bands,and it is necessary to reserch the notch performance of UWB antennas.Based on the trend of development of the antennas,this paper has carried out the design work of miniaturized UWB antenna and notch UWB antenna.Firstly,a design scheme of an ultra-wideband antenna based on the defective ground structure is proposed.Through electromagnetic analysis and calculation of the antenna structure,the influence of the ground plate slot on the antenna bandwidth is analyzed,which is to complete the preliminary scheme of the UWB antenna;then,by introducing split resonant ring(SRR)units and "cross-shaped" branches,the antenna bandwidth has gotten broadened.The practical measurement results gotten by using network analyzer(Agilent N5230A)showed that the antenna offers a-10 d B return loss bandwidth in the range of 3.0 to 19.3 GHz;besides,the antenna has stable radiation performance in the lower frequency bands.In the higher frequency bands,due to the changes of the current path compared to the lower frequency bands,the bandwidth of the antenna gets broadened,but the directivity of the UWB antenna gets worse.In the higher frequency band,the gain of the antenna changes steadily.The antenna can be used in ultra-wideband(UWB)wireless communication systems.Subsequently,a new configuration of band-notched UWB antenna is presented to solve the problem of mutual interference between narrowband communication and ultra-wideband systems.On the basis of the regular hexagonal patch antenna,a arrowhead-shaped slot and two quasi-circular slots are firstly etched on the ground plate,which is to realizes the ultra-wideband radiation characteristics of the antenna.Then,two rejection bands(wireless interoperability for microwave access and wireless local area network)are obtained by etching the incomplete hexagonal ring slot on the patch and the U-shaped slot on the microstrip feed line respectively.By using these two notching methods,the antenna achieves double notch characteristics.The actual test results of the antenna meet the design requirements.