Millimeter-wave Low-sidelobe Antenna Array With A Substrate-integrated And 3D-printed Hybrid Configuration

Millimeter-wave antenna with high gain and low-sidelobe is the core component of millimeter wave communication system such as point-to-point wireless access and high-speed backhaul.In this thesis,aiming at the problems of large volume and high profile of millimeter wave reflector antenna and large transmission loss of substrate integrated array antenna feed network,a millimeter wave low-sidelobe magneto-electric dipole antenna array with substrate integrated and metal 3D printing hybrid feed network structure is studied and designed.The antenna array combines the advantages of flexible power distribution control of substrate integrated feed network and low loss of air-filled waveguide feed network,and realizes high gain and low-sidelobe radiation of millimeter wave planar array.The main works and innovations of this dissertation are summarized as follows:1.The substrate integrated coaxial line unequal power division sub-feed network and metal 3D printed waveguide main feed network are studied and designed.According to Taylor distribution low-sidelobe array synthesis theory,the excitation amplitude distribution required by antenna array is determined.The power ratio control method of substrate integrated coaxial line power divider is studied,and a 1 to 16 unequal power division broadband sub-feed network is designed to realize the power distribution required by low-sidelobe radiation.At the same time,a compact 1 to 4equal power division broadband main feed network is designed by using 3D printed air-filled waveguide.2.On the basis of main feed network and sub-feed network,the broadband vertical transition structure of metal waveguide to substrate integrated coaxial line is studied and designed.The transition structure has compact plane size,which can be integrated into the designed substrate integrated coaxial line sub-feed network,and realizes low-loss transmission of electromagnetic energy from the main feed network to the sub-feed network.3.A broadband magneto-electric dipole antenna fed by substrate integrated coaxial line is studied and designed.As a radiating element,it is connected with unequal power division sub-feed network.In order to realize the low-cost PCB processing of antenna structure,an L-shaped probe feed structure combining metal through hole and back drilling mechanical hole is proposed,and the influence of back drilling mechanical hole size on antenna impedance and radiation characteristics is analyzed.4.Based on the broadband radiation structure and low-loss feed network studied above,an 8×8 millimeter-wave low-sidelobe antenna array working in 5G millimeter wave communication band is designed and fabricated.Experiments show that the test results are in good agreement with the simulation results.The array has an operating bandwidth of 17.31%,a stable and symmetrical radiation pattern,a sidelobe level below-18 dB,and a maximum gain of 22.3 d Bi.