Research On Millimeter Wave Shared Aperture Antenna

Inter-satellite communication has been widely used in modern communication technology,which supports high-speed,stable communication while avoiding ground communication blind spots.In inter-satellite link,due to the relative motion between satellites and ground stations,high-speed satellite-to-ground communication are required to support satellite networks and ground communication.This thesis focuses on the multifrequency,shared aperture,high-gain antennas in satellite communication and proposes a low-profile,integrated,broadband,and multifunctional shared aperture structure of reflectarray and phased array antennas,aiming to improve the spectrum and aperture utilization,and beam control capabilities of aerospace antenna payloads.Regarding the typical design methods and feasible innovations for shared aperture phased array antennas and reflectarray antennas,four typical design methods are summarized: overlapping placement,hollowed-out placement,staggered placement,and nested placement.To solve these problems including single-function,narrow working frequency band,and high-profile shapes in traditional shared aperture antenna arrays,a dual-frequency shared aperture antenna array that combines reflectarray antennas and broadband phased array antennas based on mushroom unit structures is proposed.The reflectarray antenna is operated in the Ka band,and the broadband phased array antenna is operated in the X band,with a higher working frequency ratio ensuring the independent operation of both antennas,making them suitable for high-speed communication in geostationary orbit(GEO)relay node satellites in inter-satellite links.The prototype of antenna is manufactured,and its electrical performance are tested.The reflectarray antenna has a30.1 d Bi measured peak gain and 11.4% relative bandwidth;the phased array antenna has a measured peak gain of 21.7 d Bi,with a scanning range covering ±45°.To solve the limitation in working frequency bands of shared aperture reflectarray and phased array antennas,and the high manufacturing costs,a compact tri-band shared aperture reflectarray and phased array antenna operating in satellite-to-ground and intersatellite communication frequency bands including X,Ku,and Ka is proposed.The reflectarray antennas are operated in the X and Ka bands,while the phased array antenna is operated in the Ku band.Using co-planar structure to nest high and low-frequency units and setting a grid sparse array design method,the maximum utilization of antenna aperture space is achieved.For the Ku band phased array antenna,the measured results show that the scanning angle covers ±45 degrees,and the relative impedance bandwidth remains above 10% during scanning;for the X and Ka band reflectarray antennas,the measured main lobe gains are 23.8 d Bi and 30.3 d Bi,respectively.Compared to the previously mentioned design,this design reduces the number of substrate layers,significantly decreases manufacturing costs.