Wide Angle Frequency Sweep And Single Pulse Frequency Sweep Antenna Research

Frequency scanning antenna array has many advantages such as simple structure,low cost and light weight,so it has been widely used in radar,communication,and other fields.But conventional frequency scanning antenna array also has shortcomings,like small main beam scanning angle,insufficient angle measuring accuracy.Aiming at these problems,solution to enlarge frequency scanning angle and realize frequency scanning monopulse has been studied respectively in this article.Firstly,the Composite Right/Left-Handed(CRLH)transmission line structure is applied to the substrate integrated waveguide(SIW)leaky wave antenna to realize a wide angle frequency scanning performance.According to the CRLH transmission line theory,analysing with the electromagnetic simulation software CST,the article realized a wide angle frequency scanning antenna array.Its frequency scanning angle reaches 50.7 degrees within the bandwidth of 3GHz.And the sparse array theory is applied to this CRLH leaky wave antenna array to reduce the sidelobe level.Secondly,this article designed a waveguide slot antenna array which has been applied to a phase/frequency scanning radar.The article analysed the design principle of narrow wall waveguide slot array according to equivalent circuit method.Also,it stated the design steps of narrow wall waveguide slot array.And then,a waveguide slot array has been designed,calibrated and tested in the outfield.The sidelobe level is below-25dB in the frequency scanning dimension and below-20dB in the phase scanning dimension within the working frequency band.Finally,in view of the insufficient accuracy in target position tracking of phase/frequency scanning radar,this article take a research on structure of realizing waveguides slot array frequency scanning monopulse.Distribution of one waveguide is the sum distribution of Taylor and Bayliss,and the adjacent waveguide is with the difference distribution of Taylor and Bayliss.Then,the sum and difference beams can be formed at the same time by the same and reverse phase feeding of sum-difference network.The sidelobe level of sum beam is-28.4dB,the corresponding null depth of difference beam is-32.5dB(compared with the sum beam),which verified the feasibility of this approach.