| At the optical frequency,Surface Plasmon Polariton(SPP)has received extensive attention and in-depth research due to its unique surface wave mode,and has been applied in many fields.Spoof Surface Plasmon Polariton(SSPP)is a special surface wave model proposed by researchers to extend SPP to lower frequency bands.It is generally transmitted on the surface of periodic metal structures.It has similar dispersion characteristics to SPP,and therefore has shorter operating wavelengths,higher near-field confinement,conformal transmission and other transmission characteristics.At the same time,SSPP also has the advantage that the dispersion characteristics are completely determined by its structural parameters,which provides a broad research and application prospect.On the basis of summarizing the work of the predecessors,this paper has carried out in-depth research on the compact design of Spoof Surface Plasmon Polariton transmission line(SSPP-TL)and the leaky wave antenna based on SSPP.The main work has the following aspects:1.A complementary single-side slotted comb-shaped transmission line is proposed,and the dispersion characteristics of SSPP unit are analyzed.From the perspective of the unit equivalent circuit,the basis of the groove depth control of the cutoff frequency(the equivalent capacitance between the slots)is analyzed.An idea is proposed to use the inter-slot loading interdigitation structure instead of the groove depth to achieve the cutoff frequency regulation.Then the Sparameters and electric field distribution of the SSPP-TL loaded with the interdigitated structure are analyzed by simulation.The simulation results show that the addition of the interdigitated structure does not bring about significant insertion loss in the passband.At the same time,changing the interdigitation structure can realize the flexible regulation of the cutoff frequency,meet the design expectations.Finally,we carried out the processing and testing of the physical object,and the test results are in good agreement with the simulation results.In order to verify the influence of the interdigitated structure on the electric field confinement ability of the SSPP-TL.2.Based on the structure of the complementary SSPP-TL,a Leaky-Wave Antenna(LWA)with upper and lower double beams is designed by surface impedance modulation.Firstly,we propose a complementary SSPP-TL with a unit length of 1 mm and analyze its dispersion characteristics.Combined with the theoretical calculation of surface impedance modulation,an SSPP-LWA is realized,which realizes wide-edge radiation at 8.8 GHz,at 7.0-10.0GHz,the beam sweep range from backward(-41°)to forward(39°)is achieved.3.Aiming at the problem of Open Stopband in the previous work,a method of loading a circular metal patch between the slot lines is proposed to suppress the Open Stopband effect of the leaky wave antenna.Although it sacrifices about 10% of the radiation efficiency in the 7.0-8.0 GHz band,it effectively improves the broad-side radiation efficiency.And the simulation results show that the radiation pattern has no obvious change,and the frequency sweep characteristics are still maintained.And the radiation gain is increased by about 1 d Bi in the entire frequency band,which can be considered as a method for effectively suppressing the Open Stopband effect. |
