The Transmission Properties Of Spoof Surface Plasmon Polariton

Spoof surface plasmon polariton(SSPP)can mimic the surface plasmon polariton at microwave or tera-hertz frequencies based on periodic metamaterial.The SPP mode has been widely used in novel transmission waveguides and functional devices,due to its unique properties of great confinement,shorter operating wave-length,low loss,and ability in flexible transmission.In this thesis,the functional devices based on SSPP and the combination of SSPP and traditional circuits and systems are discussed.In particular,the multi-layer and cross-layer transmissions,which are significant required techniques in future plasmonic integrated circuits,are intensively investigated.The main contents and contributions of the thesis are summarized as follows:· An improved SSPP transmission line is proposed with reduced width of the whole transmission line,especially when the operating frequency band is low.By introducing electrically resonant metamaterials near the ultrathin corrugated strip to produce tight coupling and mismatch of surface impedance,dual-band absorption-type and broadband reflection-type SSPP rejections are achieved.In the former case,two filtering peaks over 15dB are observed at 7.65GHz and 9.47GHz;and in latter case,broadband filtering from 6.8GHz to 8.1GHz over 20dB is observed.· The SSPP mode could be transmitted from one layer into another layer via metallic holes and arc-shaped transitions for both single-strip and double-strip SSPP transmission lines.The transmission coefficient of the single-strip SSPP waveguide is better than-0.8dB within the frequency band from 2.67GHz to 10.2GHz.Meanwhile,a controllable absorption related to the superposition area of corrugated strips is observed.For the double-strip SSPP waveguide,the metallic hole and arc-shaped transition contribute to highly efficient topological transmission above-1dB from 2.26GHz to 11.8GHz.· A novel SSPP transmission line used in multilayer multichannel transmissions is proposed.Very good isolation properties between two overlapped SSPP waveguides are achieved with limited width of the background layer.More importantly,the isolation or coupling property between the two overlapped waveguides can be switched by tuning the opening direction of the corrugation grooves.Since each channel of the multilayer system operates independently,it is convenient to realize multilayer multi-functional SSPP devices.A prototype of bifunctional device with two significant rejections at 7.6GHz and 8.4GHz in each channel is designed.Rejection in one channel would not break the transmission in the other channel on different layer.· A novel miniaturized SSPP transmission line is proposed in which the width is narrowed by 70%.An innovative approach of decoupling for dual-band microstrip antenna,combining the high-pass property of substrate integrated waveguide(SI W)and the low-pass property of SSPP,is presented.The decoupling design is available for most dual-band network whose operating bands locate on two sides of the cut-off frequency.The radiation element could be replaced without redesigning the decoupling network.And such design could be considered as part of radio-frequency front-end circuits,since both SIW and SSPP could be used in functional devices such as multi-way power divider.So the actual space the design occupies is small.The decoupling network could provide improvement of isolation by more than 20dB within a wide band.And it has no influence on the properties of radiation elements.· A leaky-wave radiation based on complementary SSPP transmission line is proposed,in which the frequency-scanning on both sides of the transmission line is achieved.Meanwhile,a two-class-coupling decoupling design for dual-polarized microstrip antenna is proposed.The near field distribution of in-terdigital structure under excitation works as secondary excitement of split-ring resonator.For a 1 x 2 dual-polarized microstrip antenna array,the mutual coupling is lower than-30dB and-40dB for co-polarization and cross-polarization respectively.