Study And Design Of UWB Low Profile Omnidirectional Antenna And UWB Array Antenna

Based on the pursuit of ultra-wideband communication,ultra-wideband communication equipment has become an important trend of development with a broad application prospects in the field of communications,therefore the ultra-wideband antenna has become a research hotspot at this stage.This paper focuses on the UWB technology of antennas and arrays,two ultra-wideband low-profile omnidirectional antennas and a 45°diagonal polarization ultra-wideband array antenna were designed and implemented.Research work consists of two parts:1.UWB omnidirectional antennas.Two omnidirectional antennas with ultra-wideband low-profile characteristics operating in the VHF and UHF bands were designed.On the basis of the single-cone antenna,by adopting a combination of loading techniques such as metal top loading,short-circuit column loading,and annular seam loading,a VSWR≤3 and a profile height of 0.05λ_Lwere achieved within a 2.3 times frequency bandwidth.The out-of-roundness in the horizontal plane pattern less than 3dB.Another low-profile omnidirectional antenna with 4 times frequency bandwidth was designed to achieve a VSWR≤2.7 and a profile height of only0.04λ_Lby using a matching circuit and resistance loading technique.2.an ultra-wideband array antenna with 45°polarization was designed.By optimizing the design of the Vivaldi antenna array unit,the number of cells was minimized and the appropriate cell spacing was selected according to the overall requirements while satisfying the array gain requirement.A detailed study and design of the feed network were conducted,and a feed network capable of satisfying the work of the ultra-wideband array was obtained.Using reflectors and metal cavities to increase antenna gain.The measured results verify the correctness of the design ideas and methods.The VSWR≤3 and the minimum gain is 10.5dBi when the operating bandwidth of 5 times frequency is reached,meeting the design requirements.