High Isolation W-Band Substrate Integrated Waveguide Array Antenna Design

Compared with the low frequency band,the W-band(75-110 GHz)has a small structural size and good communication security,and is suitable for military security.In the W-band transmission,conventional microwave transmission lines such as metal waveguides and planar microstrip lines have various disadvantages.Except for the influence of the processing technology,Dielectric loss of the microstrip line transmitted in the W band will increase.Metal waveguides perform well in the W-band transmission,but are not suitable for complex circuitry due to their closed structure.Substrate integrated waveguide(SIW)combines the advantages of both microstrip line and metal waveguide,and is suitable for W-band transmission.This thesis uses SIW as the transmission line to design the W-band array antenna.High-isolation SIW array antenna complete module consists of two parts.One part is SIW array antenna and the other part is electromagnetic bandgap(EBG).The SIW array antenna portion includes a receiving antenna and a transmitting antenna,and the receiving antenna and the transmitting antenna have exactly the same structure as a 8x12 slot radiation array.Designing the antenna module has two steps:The first step is to design the SIW array antenna,and the other step is to design the electromagnetic bandgap(EBG).The design of the transceiver SIW array antenna includes a single SIW antenna design,and the radiating part and the feeding part of the SIW array antenna are designed.Specific steps are as follows.Firstly,design single SIW antenna.Open 12 slits in the upper surface of a single SIW and then use the integrated method of Taylor's aperture distribution to determine the radiation voltage level of each gap.Then voltage level distribution is converted into a normalized admittance distribution by an equivalent circuit model.Extract the electrical parameters of single SIW and find the distance from the center of the gap(eccentricity)as a function of the resonant length and the functional relationship between the eccentricity and the normalized admittance.The accuracy and accuracy of the extracted electrical parameters can be verified by simulating a single SIW antenna.Then design the radiated and fed parts of the SIW array antenna.The eight SIW antennas are equally spaced to form the radiating portion of the SIW array antenna,and the SIW tree power splitter is the feeding portion of the SIW array antenna.The extracted electrical parametric data needs to be extracted again because the gap coupling between the SIW antennas is not considered.In this thesis,the small 5x6 array model is designed to extract the active admittance parameters again to obtain the relationship between the gap eccentricity,the gap resonance length and the active admittance.Eccentricity and resonance length of the slot of the radiating portion of the SIW array antenna can be also obtained.In order to realize the normal feeding of the radiated portion of the SIW array antenna,a 1-minute 8-phase balanced unequal power splitter of the SIW structure is designed as the feeding portion.Design a standard waveguide to SIW vertical transition structure for antenna testing and practical use.Finally,the three parts of the radiating part,the feeding part and the vertical transition structure of the SIW array antenna are connected for overall simulation.Finally,design mushroom-type EBG structure to improve the isolation of the transceiver antenna Transceiver SIW array antenna isolation refers to 55dB.The substrate integrated waveguide array antenna module was processed and tested to compare the results of the simulation and testing.