Research On Antennas And Circuits Based On Gap Waveguide

Gap waveguide represents a state-of-the-art transmission line structure that emerges in recent years.With the stop band effect of the periodic electromagnetic bandgap(EBG)structure,it suppresses electromagnetic wave propagation in specific frequency band so as to eliminate electromagnetic leakage.Because of its natural advantages of low loss,large bandwidth and no electrical contact,it plays an important role in the research of circuits and antennas.Therefore,based on the gap waveguide technology,this paper has carried out research and design on the circuits and antenna,and the scientific research is outlined as follows:1.The basic structure and working principle of ridge gap waveguide(RGW)and groove gap waveguide(GGW)are analyzed.Based on the quasi-static electromagnetic analysis,a theoretical analysis of the dispersion relationship on the surface of the high impedance EBG is carried out.And using the dispersion curve to study the electromagnetic band gap characteristics of the EBG structure,a detailed parameter analysis was carried out,and the influence of the important size parameters of the pin on the electromagnetic band gap was obtained.2.A high front-to-rear ratio H-plane horn antenna based on GGW is designed.Introduce a gradual trapezoidal structure on the upper and lower inner surfaces to improve the aperture field distribution,increase the front-to-back ratio,and enhance the directionality.In the rectangular waveguide-GGW transition structure,a stepped structure is used to improve impedance matching.The simulation results show that the improved antenna gain is increased by 3dB on average,and the front-to-back ratio is increased by 6.5dB.3.A Magic-T based on RGW is proposed.Use a novel " staircase " gap to replace the traditional rectangular gap,broaden the bandwidth,and use metal stepped ridges in the gap coupling structure to improve impedance matching.At the same time,the relative center positions of the upper and lower metal layers have been re-adjusted to make the overall structure of the magic T more symmetrical and energy coupling more sufficient.The sum and difference branches of the magic T use RGW as the transmission line,so there is no need for mode conversion,which simplifies the design,and realizes low insertion loss and good amplitudephase imbalance.4.A spatial power combining module based on E-plane GGW is proposed.The structure of power division network and multiple E-plane horns is adopted to form a uniform field distribution in the over-mode waveguide space.Using a microstrip array composed of 16 fin lines aligned along the E-plane direction,the overmode waveguide is divided into 16 transmission channels,so that the input power is evenly distributed to the microstrip array.The simulation and actual measurement results show that the insertion loss of the back-to-back module in 30-40 GHz is less than 1dB,and it has achieved good transmission performance.