Research And Design Of UWB Antenna Based On High Speed Rail And Aircraft Platform

In recent years,wireless communication technology has been integrated into all aspects of people’s lives.As an important part of sending and receiving radio waves,the antenna’s structure and performance directly affect the quality of the entire communication system.High-speed rail and aircraft are new types of vehicles that are rapidly developing.More and more people choose high-speed transportation,which puts higher demands on their information services.In this thesis,three UWB antennas are designed by UWB antenna theory and its application scenarios,including two high-speed rail antennas and one airborne antenna.The specific contents are as follows:The first antenna is a low-profile MIMO high-speed rail antenna.Considering the size requirements of the antenna,the MIMO antenna is composed of two planar inverted-F antennas to ensure the overall size of the antenna system.The high isolation is achieved by loading an electromagnetic band gap structure on the metal base between the antenna elements for the lower band.The antenna element uses a multi-branch structure and a gradual feed structure to expand the bandwidth of the antenna.Finally,the MIMO antenna achieves 698-960 MHz and 1710-6000 MHz frequency band coverage,and the port isolation of the two antenna units in the required frequency band is above 20 dB,and the maximum gain of the antenna is above 6.5dBi.The actual performance of the antenna is verified by antenna proofing,and the radiation characteristics of the antenna meet the requirements.The second antenna is a high-speed rail combined antenna.The combined antenna consists of a communication antenna and a navigation antenna.The communication antenna adopts the form of inverted L antenna.The antenna bandwidth is expanded by the multi-node structure,so that the working frequency band of the communication antenna can cover 400-470 MHz,698-960 MHz,and 1710-6000 MHz.The gain of the antenna is above 3.5dBi at low frequencies and above 6dBi at high frequencies.A navigation antenna that works on BD B1,GPS L1,and GLONASS L1 is designed by adopting Wilkinson power divider and using an electromagnetic band gap structure as the floor,the axial ratio is less than 3dB and the gain is improved in the working band..The antenna has completed the verification of the antenna communication effect after proofing and actual measurement.The third antenna is an airborne antenna,which adopts the form of a planar sleeve antenna.The matching circuit and loading technology are used to broaden the impedance bandwidth and reduce the size of the antenna.The antenna achieves a wide impedance band of 108-678 MHz,and a good omnidirectional radiation performance.