| Ultra-Wideband(UWB) communication technology has been widely used in wireless communication,radar and indoor positioning due to its high data transmission rate,low power consumption,good confidentiality performance and high multipath resolution.The UWB-MIMO technology combined with UWB technology and multiple-input multiple-output(MIMO)technology can increase channel capacity and suppress multipath fading effects without increasing bandwidth and power.The antenna is an important part of the communication system,and its performance has an important impact on the entire system.The UWB antenna is an important part of the communication system,and its performance has an important impact on the entire system.In order to solve the problem of narrowband interference in UWB working frequency range,the design of UWB antennas and UWB-MIMO antennas with multiple band-notched characteristics has theoretical significance and practical value.This thesis designs UWB antennas with multiple band-notched characteristics and UWB-MIMO antennas with high isolation and multiple band-notched characteristics by studying basic theoretical knowledge of antenna.The main contents include:1.An ultra-wideband antenna with sextuple band-notched characteristics is designed.The antenna is composed of an elliptical radiating patch and a rectangular ground.The overall of the antenna size is 38×40×0.8mm~3.The antenna has realized sextuple band-notched functions by etching two C-shaped grooves of different sizes on the radiating patch and placing four various U-shaped parasitic strips on both sides of the feedline.At the same time,the equivalent circuit model of the antenna is proposed and analyzed.The antenna has been fabricated and measured,which results show that the antenna has good band-notched characteristics,good radiation characteristics and stable gain in working frequency.2.A dual-band rejection ultra-wideband MIMO antenna with high isolation is designed.The antenna is composed of two radiating elements and a common ground.The overall size of the antenna is 39×30×0.8mm~3.The antenna realizes the rejection function of two different frequency bands by etching two elliptical grooves on the radiating patches.The two concave grooves and a pair of arc-shaped grooves etched on the ground plane have broadened the antenna working impedance bandwidth and improved the isolation between antenna elements.Besides,the equivalent circuit model of the antenna is proposed and analyzed.The antenna has been fabricated and measured.The measured results show that the antenna has two band-notched characteristics in working frequency,the isolation is greater than 19d B,the envelope correlation coefficient is less than 0.004,good radiation performance and stable gain.3.A quad-band rejection ultra-wideband MIMO antenna with high isolation characteristics is designed.The overall size of the antenna is 39×30×0.8mm~3.The two radiating elements of the antenna are connected by a common ground plane.The antenna has two U-shaped grooves of different sizes etched on the radiating patches to obtain two band-notched characteristics at the WLAN band and the extended C-band.The two U-shaped parasitic strips of different sizes placed beside the feedline to obtain band rejections at the X-band and RN-band.The antenna achieves high isolation between two ports by using a simple decoupling structure.At the same time,the equivalent circuit model of the antenna is also analyzed.The antenna has been fabricated and measured.The measured results are in good agreement with the simulated results.The results show that the antenna has four obvious band rejections in working frequency,the isolation is greater than 20d B,the envelope correlation coefficient is less than 0.02,good radiation performance and stable gain. |
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