| Leaky-wave antenna(LWA)has attracted much attention because of its high directivity,compact structure and no need for complex and expensive feed network like phased array.With the increasing demand for wireless system,LWA has ushered in new challenges.How to improve its performance and enrich its functions has become an important research direction.As an electromagnetic wave existing on the surface of subwavelength periodic structure,spoof surface plasmon polaritons has the characteristics of strong field binding,tunable dispersion and high-frequency cutoff,which can be used in the design of leaky wave antenna.Therefore,based on the advantages of spoof surface plasmon polaritons,this paper analyzes and studies the problems of low scanning rate and open stopband(OSB)of traditional leaky wave antenna,and designs three new leaky wave antennas.The main contents are summarized as follows:(1)A new type of LWA with double conductor spoof surface plasmon polaritons is designed.By periodically loading sinusoidal patches on both sides of the two-conductor spoof surface plasmon polaritons,the electromagnetic wave can be radiated outward,and the beam scanning from-34 ° to+ 21 ° can be realized.The antenna has strong directional radiation ability,the half power beam widths(HPBWs)is between 10-20 °,the sidelobe level is lower than-10 d B,and the radiation efficiency is as high as 95%.(2)A LWA with high scanning rate based on microstrip spoof surface plasmon polaritons is designed and realized.Because the microstrip spoof surface plasmon polaritons has stronger dispersion characteristics than the general artificial surface plasmon polaritons,it can greatly improve its beam scanning rate.The scanning angle range of 99 ° is realized in the narrow band of 6.65-7.25 GHz and 600 MHz,and the scanning rate is as high as 165 ° / GHz.At the same time,by introducing asymmetric metallized vias,the open stopband effect is suppressed,so that the high scanning rate antenna can realize continuous scanning,stable directivity,and the average gain reaches11 d Bi.(3)A LWA with series parallel hybrid loading is designed.For the LWA with periodic structure,the reflection introduced by loading a radiating element cannot be completely eliminated.Therefore,a design method of introducing complementary elements to realize impedance matching is proposed to solve the open stopband problem of leaky wave antenna.Through series parallel hybrid loading,the inductance and capacitance of the two elements are complementary.In the 8.1-11.6GHz frequency band,S11 is lower than-10 d B,the stopband is completely eliminated,and the maximum gain of the simulation is 14.7d Bi in the broadside.At the same time,the continuous beam scanning from-53 °forward to + 31 ° backward is realized,and the sidelobe level is lower than-10 d B. |
