Ku-band Wideband Low-profile Metasurface Antenna

Due to the fixed electromagnetic performance of the traditional antenna,the application of the traditional antenna is limited.Therefore,a new electromagnetic design method is urgently needed to solve the problems faced by the traditional antenna.Metasurface is a new type of structural material,which has characteristics that natural materials do not possess.It can break the physical limits of traditional antennas and innovate the way humans control electromagnetic waves.Metasurface antennas generally use air-fed mode,but because the fixed transmission path in space has different phase delays at different frequencies and is limited by the unit bandwidth,its working bandwidth is generally narrow.With the development of wireless systems,more and more application scenarios require antennas with low profile.Therefore,it has important research significance to solve the problems of the narrow working bandwidth and high profile of metasurface antennas.The main research content of this article is divided into the following points:1.Aiming at the problems of high profile and narrow bandwidth in the traditional metasurface to achieve full phase modulation,a wideband low-profile metasurface antenna with ultra-thin air layer was designed.The antenna expands the working bandwidth by introducing multiple resonance frequency points,and an ultra-thin air layer to achieve impedance matching,which reduces the antenna's backward radiation and improves the antenna's gain.Compared with the traditional metasurface antenna,this design eliminates the 1/4? cascade air layer,and the overall thickness of the metasurface is 0.165?.The-1d B gain bandwidth of the wideband low-profile metasurface antenna designed in this paper is 37.3%,the aperture efficiency is 42.3%,and the antenna gain decreases by 3.6d B when scanning to ±30°.2.The performance of metasurface antennas and continuous phase compensation circularly polarized metasurface antennas under different phase quantization of 1bit,2bit,and 3bit was investigated and compared.The performance of metasurface antennas and continuous phase compensation circularly polarized metasurface antennas under different phase quantization of 1bit,2bit,and 3bit was investigated and compared.The characteristics of circularly polarized metasurface antennas with different phase quantization are compared.The higher the number of phase quantization bits,the higher the gain and the lower the axial ratio,but the narrower the-1d B gain bandwidth of the metasurface antenna,and the antenna gain decreases by 2.89 d B when scanning to ±40°.3.Due to the long distance from the feed source to the metasurface,in order to reduce the overall height of the metasurface antenna,a wideband circularly polarized low-profile metasurface antenna with folded focal length is designed.The antenna is composed of a polarization conversion metasurface,a circular polarization transmission metasurface and a feed source.In order to expand the working bandwidth of the polarization conversion metasurface and increase the polarization conversion rate,multiple electrical resonances and magnetic resonances are introduced in the polarization conversion metasurface.In order to expand the working bandwidth of the polarization conversion metasurface and increase the polarization conversion rate,multiple electrical resonances and magnetic resonances are introduced in the polarization conversion metasurface.The measured-3d B gain bandwidth of the antenna is 21.43%,and the 3d B axial ratio bandwidth is 26.43%.