Research Of Leaky Wave Antenna Based On Substrate Integrated Waveguide

As a typical type of traveling wave antennas,leaky wave antennas have the characteristics of high gain and frequency sweep,and have been widely used in frequency modulated continuous wave radar,real-time spectrum analysis,and field pattern synthesis.However,conventional leaky wave antennas based on closed waveguide structures(large volume and difficulty of being integrated into planar microwave circuits)have many problems,which limit the development of leaky wave antennas.Substrate integrated waveguides(SIWs)not only inherits the ideal transmission performance of the closed waveguide structure,but also facilitate the easy integration into the planar circuit,which brings new vitality into the development of the leaky wave antenna.In this paper,the radiation mechanism of the leaky wave antenna is elaborated.On this basis,the substrate integrated waveguide leaky wave antenna is used as the basic structure,and the cause of the open stop band is analyzed by an equivalent circuit model and electromagnetic simulations.Furthermore,on the basis of the basic structure,a circularly polarized leaky wave antenna,a half-mode substrate integrated waveguide leaky wave antenna,and a composite right/left-handed leaky wave antenna loaded with a frequency selective surface(FSS)are proposed,respectively.Major work of the thesis includes:1.A circularly polarized SIW periodic leaky wave antenna with suppressed stopband is proposed.The antenna is composed of ten radiating elements with "? " shaped slots to suppress the open stopband effect and provide circularly polarized radiation.The measured results show that the antenna can achieve a circular polarization scan from-29° to 32° in the operating frequency band of 10.1-13 GHz.Compared with the research previously reported in recent years,the proposed has a higher frequency-sweep sensitivity in the operating frequency band..2.An HMSIW leaky wave antenna with a metalized vias array at the open boundary is proposed.Aiming at solving the problems of the energy leakage at the open boundary and the inability to perform continuous beam scanning of the traditional halfmode substrate integrated waveguide leaky-wave antenna,an array of metalized vias are introduced at the open boundary of the waveguide,which significantly increases the antenna gain.The surface of the waveguide has radiating elements composed of transverse and longitudinal slots,which suppresses the open stopband effect of broadside radiation,enabling the antenna to achieve continuous beam scanning from backward to forward.The actual measurement results show that the antenna can achieve a wide-angle beam scan of-51 ° to 24 ° in the 9-13 GHz operating frequency band,and the actual measured gain range is within 6.9-12.3d Bi.Compared with the same type of antennas reported in the past,the antenna proposed in this paper has a larger beam scanning range and scanning sensitivity.3.A CRLH-SIW leaky wave antenna with FSS is designed.The forbidden band is eliminated by optimizing the parameters of the interdigitated slot,so that the antenna can perform continuous scanning.By adding the frequency selective surface above the fed CRLH antenna,the antenna gain is effectively increased.The simulation results show that the antenna can achieve a beam scan of-47 ° to 50 ° in 9-13 GHz,and the corresponding gain is from 11.5 d Bi to 16.32 d Bi,which is 1.2-3d B higher than the nonloaded(no FSS layer)counterpart.The proposed antenna has a low cross-polarization level while maintaining high gain and wide-beam-scanning capability.