Research On Low-Profile UWB Wide-Angle Scanning Phased Array Antenna

As aircraft perception abilities continue to improve,more electronic components are being added,resulting in a crowded space.To address this issue,there is an increasing demand for radar integration enhancement,and lowering the antenna profile has proven to be a practical and effective solution.Traditionally,as the phased array bandwidth expands,the profile of the impedance converter also increases.To ensure smooth impedance transformation during wide-angle scanning,the frequency selective surface wide-angle scanning matching layer needs to be continuously increased.However,this increases the overall profile of the antenna.To further reduce the overall radar profile,this thesis presents the design of a low-profile ultrawideband wide-angle scanning phased array antenna.The design includes:（1）Design of a low-profile ultra-wideband wide-angle scanning phased array antenna unit and resistance card.This part involves the design of an antenna unit consisting of four parts that can realize ultrawideband wide-angle scanning.The frequency selective surface wide-angle scanning matching layer replaces the previous dielectric scanning matching layer,improving the wide-angle scanning capability of the array and reducing the profile.The tightly coupled dipole is used to realize ultrawideband and wide-angle scanning of the array,while the curved strip-line Marchand balun completes the impedance transformation and lowers the profile.The resistance card solves the problem of ground reflection caused by the reduction of profile.By adding the newly designed resistance card and rearranging the metal patch on it,the original material can be replaced with simple and easily available materials,and the traditional design method can be improved to meet the needs of high-frequency working.The four parts are printed on the dielectric substrate with the"sandwich"structure,and the design achieves a bandwidth of 2.9-15.7 GHz（5.4:1）and a profile height of 0.1λ_low,under the premise of the voltage standing wave ratio<2.5,whereλ_low is the wavelength of the lowest operational frequency.（2）The design and machining testing of a low-profile ultrawideband wide-angle scanning phased array antenna system was conducted.The antenna system is composed of a regular array of 256 units arranged in a 16x16 configuration,and employs the isophase lines,delay lines,and power dividers to enable phased array scanning.The assembled array underwent a pattern test using the near field test method,and the design objective of achieving±70°scanning in the E-plane and H-plane was effectively achieved.