| Electromagnetic band gap(EBG)structure and photonics crystal band gap(PBG)are two concepts which respectively belongs to microwave frequency band and optical frequency band.The photonics crystal structure was firstly proposed independently by two researchers in Bell Laboratory and Princeton University respectively.Because the photonics crystal features tiny dimensions which determines its processing is rather difficult,the concepts of band gap structure in optical frequency band was developed into microwave frequency band which also abides by the Maxwell equation,deriving the concepts of EBG.Uniplanar compact electromagnetic band gap(UC-EBG)is widely studied and used because of its simple manufacturing.The thesis mainly studies the influence of UC-EBG on performance improvement of millimeter wave antenna,and proposes wide band and high gain antennas applied to millimeter wave band.The conclusions are as follows:Firstly,this paper studies capacitive type electromagnetic band gap(CT-EBG)to improve the gain performance of 60GHz aperture coupled microstrip line feed patch antenna(ACMPA).The CT-EBG has a reflection phase band of 55?63.9GHz.One round of CT-EBG is loaded on the same layer with radiating patch,and with a distance of 2.84mm to it The antenna's gain performance is improved because of better energy distribution The bandwidth and highest gain of primary antenna are 57.54?61 25GHz and 8.5dBi in the millimeter wave free band.And those of the CT-EBG antenna are 57 2?61GHz and 10.4dBi.The CT-EBG ACMPA can be the preparation research for the following two high gain and broadband antennas.Secondly,this paper studies the umbrella type uniplanar-compact electromagnetic band gap(UT-UC-EBG)to improve the performance of 60GHz magneto-electric(ME-)dipole antenna.The novel UT-UC-EBG has a reflection phase band of 53.7?65.7GHz.Bandwidth and gain of antennas with substrates of different dimensions have been studied.The variation of substrate dimension has little influence on antenna's bandwidth,but has a significant impact on its gain performance.When the side length of substrate is 30mm,the primary antenna features characteristics as follows:bandwidth of 43.3?66.6GHz,highest gain of 9.37dBi in 57?66GHz and peak gain of 9dBi at 60GHz.After loading one round of UT-UC-EBG at a distance of 7.5mm to the center of the substrate,the UT-UC-EBG features characteristics as bandwidth of 43.5?68.6GHz,highest gain of 13.9dBi in 57?66GHz and peak gain of 11.6dBi at 60GHz When the side length of substrate is 12mm,the primary antenna features characteristics as follows:bandwidth of 44?67GHz,highest gain of 9.31dBi in 57?66GHz and peak gain of 9.3dBi at 60GHz.After loading one round of UT-UC-EBG at a distance of 5mm to the center of the substrate,the UT-UC-EBG features characteristics as bandwidth of 43.9?67.7GHz,highest gain of 10.1dBi in 57-66GHz and peak gain of 7.64dBi at 60GHz.Therefore,the UT-UC-EBG antenna with 30mm side length has a relatively stable and higher gain than the 12mm one.Finally,this paper studies the meshed bidirectional symmetrical I-shaped slot uniplanar-compact electromagnetic band gap(MBSIS-UC-EBG)based on the primary meshed monopole antenna.MBSIS-UC-EBG has a reflection phase band of 58.7?61.7GHz.By applying MBSIS-UC-EBG around the primary antenna,the antenna's peak gain at 60GHz has been improved to 5.8dBi from-5.3dBi.The MBSIS-UC-EBG antenna has a bandwidth of 46?72.5GHz(relative bandwidth of 44.7%),8.3GHz wider than that of the primary antenna.The MBSIS-UC-EBG can dramatically improve the antenna's performance without seriously affecting its transparency.The designed MBSIS-UC-EBG antenna can be used on building windows,optical panel,monitor of mobile device and windows of vehicle,etc. |
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