A Study Of Microstrip Gap Waveguide Slot Antenna

The waveguide slot antenna has the advantages of integration,low profile,easy to be conformal with its carrier,and has a wide application prospect in the field of communication.But in high band,rectangular waveguide are difficult to machining.Compared with traditional waveguide,the processing technology of microstrip gap waveguide is simpler.As we all know,the higher frequency takes the more difficulty in processing of traditional waveguide's cavity structure.The structure of microstrip gap waveguide is composed by mushroom-like EBG which is arranged around the microstrip line on the surface of a dielectric plate of parallel plate waveguide.The role of EBG structure makes the electromagnetic wave won't overflow around in the absence of waveguide wall.The manufacturing process doesn't need connection,also doesn't need other isolation components.So It won't have to consider additional resonance.This paper mainly focuses on the design process of microstrip gap waveguide slot array antenna.Its main work and research results are as follows:1.A gap waveguide slot antenna in high frequency band with central frequency of 60 GHz is designed.In order to solve the problem of grating lobe caused by gap waveguide technology.The low cost dielectric plate was used.A piece of dielectric plate was placed above about a quarter of working wavelength.And dielectric plate is equivalent to a lens.The simulation results show that the antenna gain increases by 7 dB and greatly reduces the grating lobe.2.In order to make the measurement and verification of the physical antenna,the high-frequency antenna was reduced to the k-band.The microstrip gap waveguide structure is improved to separate the microstrip line from the EBG structure,and then the power divider of the antenna is designed.3.By changing the shape of the microstrip line of the linear polarization antenna and using the method of rotating the antenna gap,a circular polarization microstrip gap waveguide slot antenna which working at K-band is designed.The axial bandwidth is 13.4% and gain is 9.4d Bi at the frequency point of 22 GHz.4.We made the linear polarization waveguide slot antenna polarization microstrip line as the array element,and a 2×2 waveguide slot array antenna is designed.The transition device of the waveguide to microstrip is designed to meet the needs of actual measurement.The relative bandwidth of the antenna array is 26.95%,the gain is 14.27 d Bi at 23 GHz,the sidelobe level is-9dB,and cross polarization is-13 dB.5.To further improve the gain,lower the sidelobe level and optimize the cross-polarization.In this paper,an 8×8 microstrip gap waveguide slot array antenna is designed.The gain of array antenna is greatly improved,with the gain up to 24.2d Bi at the central frequency point of 22.8GHz,and sidelobe level is-14 dB,while the cross-polarization is-28 dB.