Research On Design Method Of Broadband Microstrip Antenna

In recent years,with all kinds of new wireless communication technology and theory has been put forward,and widely used in wireless communication equipment,wireless communications industry has been booming.Many wireless communication devices in daily life can be seen everywhere,such as mobile phones,Bluetooth,WLAN wireless network card,GPS navigation and so on,and these electronic products need antenna to send and receive communication signals.Antenna is the key device to control the transmission and reception of communication signal in wireless communication system.The performance of the antenna will directly affect the quality of the whole wireless communication equipment and the quality of the communication system.A very important branch of antenna is microstrip antenna,compared with other types of antennas,microstrip antenna because of its low cost,small volume,light weight,easy integration and electric performancediversification etc.,is widely used in wireless communication system.A so-called microstrip patch antenna is a resonant antenna with a higher quality factor.This also determines the microstrip antenna with narrow bandwidth,this paper mainly aimed at the narrow band characteristics of the microstrip antenna to carry out research and design.In this paper,the theoretical analysis method,numerical analysis method and various parameters of the microstrip antenna are introduced.At the same time,different methods of improving the bandwidth of the microstrip antenna is analyzed,And then the factors affecting the frequency bandwidth of the microstrip antenna are analyzed,and discusses the different shapes of radiation patch will effect the performance of the antenna,finally designs the structure of two layer medium U-slot antenna microstrip antenna.The main work of this paper is the following three parts:(1)According to the basic design theory of the microstrip antenna,a 2.45GHzrectangular microstrip patch antenna with coaxial feed-in is designed.By changing the material of the dielectric substrate,the thickness of the dielectric substrate,the position of the feed point and the length of the patch antenna,the influence of the changes of these factors on the performance of microstrip antennas is studied.(2)At the center frequency of 2.45 GHz,three kinds of microstrip patch antennas with rectangular,circular and triangular shapes are designed and simulated respectively,through the analysis of the three kinds of microstrip patch antenna return loss S11,feed position and gain pattern simulation results.The influence of radiation patch shape on antenna characteristics such as bandwidth,gain and directionality of microstrip antenna is discussed.(3)Based on the rectangular microstrip patch antenna,a U-slot microstrip antenna with double-layer dielectric structure is designed,and a new resonant frequency is generated by the U-shaped chip slotting technique.The two high and low resonant frequencies point close to each other,thereby improving the bandwidth of the microstrip antenna.In addition,the double-layer dielectric structure increases the thickness of the dielectric substrate,and reduces the equivalent dielectric constant,and further broadens the bandwidth of the microstrip antenna.The simulation results show that the relative bandwidth of the antenna is greatly improved in the frequency band of 2.5GHz to3.5GHz.compared with the ordinary microstrip antenna with a bandwidth of 3%,stretching about 8 times to reach the purpose of broadening the bandwidth of microstrip antennas.