| Spoof surface plasmon polariton(SSPP)waveguide is a novel type of waveguide with low loss,precisely adjustable dispersion characteristics,compact and diversified structure.It is expected to meet the challenges of miniaturization,signal interference suppression in the future development of microwave and millimeter wave integrated circuits.It is one of the key technologies in the next generation of integrated circuits.According to different application requirements,several kinds of SSPP waveguides and functional devices are studied and designed.The main work is as follow:1.A high efficiency and low coupling V-shaped microstrip SSPP transmission line is designed.Firstly,the dispersion characteristics of V-shaped microstrips and the ability of different size parameters to control the dispersion characteristics are analyzed,and a control method is proposed to improve the field confinement ability without increasing the lateral dimension by adding the fold stub.Compared with the traditional microstrip line,the proposed V-shaped microstrip transmission line has higher field confinement,lower coupling effect and stronger anti-crosstalk ability in the 0-10 GHz frequency band.V-shaped microstrips is formed by simply bending the traditional microstrip line,which has universal significance,and provides a new design idea for solving the signal interference suppression problem of very large scale integration high-speed circuits with SSPP waveguides.2.In order to make full use of the miniaturization potential of SSPP waveguides,a novel SSPP waveguide based on double-sided parallel-strip line(DSPSL)is designed.Compared with comb-shaped SSPP structure at the same asymptotic frequency of dispersion curve,the transverse dimension of the proposed DSPSL SSPP structure is reduced to 19.85%,which has obvious miniaturization advantage.Due to the double conductor structure,the proposed waveguide can be easily integrated with active devices,and it will not cause signal distortion at ultra-low frequency.In addition,based on the proposed SSPP waveguide,a narrow band notch filter with a notch frequency tuning range of 900 MHz and two broadband band notch filters with a bandwidth tuning range of 380 MHz are designed.By changing the value of the capacitance on the notch filters,we can flexibly adjust the center notch frequency and notch range,which fully proves the miniaturization advantage of the proposed waveguide and the application potential in microwave devices or systems.3.With the explosive growth of data brought by the 5 G mobile communication system,the shortage of spectrum resources is becoming increasingly prominent,and the use of vortex wave with orbital angular momentum(OAM)for mode multiplexing is expected to further improve the spectrum utilization and increase the channel capacity.Based on the principle of leaky wave antenna(LWA),a compact and efficient vortex antenna is designed by using SSPP waveguide.The proposed antenna can simultaneously radiate right-handed and left-handed circularly polarized vortex waves with opposite topological charges at the upper and lower sides,and it does not need a complex feed network.Only by adjusting the operating frequency,vortex beams with 5 OAM modes can be generated.4.A reconfigurable SSPP vortex antenna based on uniform semi elliptical array loading is designed.The proposed antenna can generate multiple modes of vortex waves without changing the structure and only changing the frequency.At the same operating frequency,the on-off state of PIN diode is adjusted by bias voltage to realize the mode reconstruction of two OAM modes.This design structure and method is expected to be applied to wireless communication system,using OAM multiplexing and demultiplexing to further improve the spectrum utilization and channel capacity. |
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