Research Of Microwave Passive Components Based On SSPP Structure

With the rapid development of wireless communication systems,the transmission frequency used by wireless communication is getting higher and higher.The increase in transmission frequency makes the system place higher requirements on the size and loss of the microwave devices used.With the increase of frequency,the insertion loss of devices designed based on traditional microwave transmission lines in the original communication system has gradually increased.Because the spoof surface plasmon polaritons,a new type of microwave structure,has slow-wave characteristics in the microwave frequency band and has a field confinement effect on the electromagnetic field,microwave passive devices designed based on such structures have advantages in size and insertion loss.In addition,through the study of its transmission characteristics,it is found that the selection of this type of transmission line structure improves the adjacent coupling in the microwave system and the outer package size of the device.Moreover,due to its tunable dispersion characteristics,it has the advantages of simple design and so on.From the above characteristics,it can be seen that the spoof surface plasmon polaritons structure is very suitable for the development trend of modern wireless communication technology,and it is widely used in high-frequency microwave design.Although the spoof surface plasmon polaritons has the above-mentioned advantages,but its application research is relatively inadequate.This article focuses on the research of the electromagnetic properties of the spoof surface plasmon polaritons,the specific research results and work have the following points:1.The transmission characteristics and dispersion curves of the spoof surface plasmon polaritons structure are studied in detail,and compared with the existing transmission line structure,it is found that the spoof surface plasmon polaritons structure has great advantages in size,insertion loss,etc.and then analyzes its possible advantages of electromagnetic characteristics in microwave structure design.2.After analyzing the structure of the classic double-sided zigzag artificial surface plasmon unit,we combine the substrate integrated waveguide and the spoof surface plasmon polaritons structure to design the SIW-SSPP structural unit.We analyze the influence of several key parameters in the structural unit on the dispersion curve and the cut-off frequency of the unit.Since the spoof surface plasmon polaritons can not be directly connected to the test system,the transition structure of several other transmission lines to the spoof surface plasmon polaritons is analyzed,and the transition structure of the SIW to the artificial surface plasmon is designed to realize the insertion within 8-16 GHz broadband efficient transition from TE mode to TM mode with loss less than-1.5d B.3.Based on the structural unit of SIW-SSPP,a full-mode band-pass filter and a half-mode band-pass filter based on SSPP are designed in this paper to achieve the miniaturization of this structure.After processing and measuring the half-mode filter,this half-mode filter achieves a band-pass transmission with a return loss better than-10 d B in the passband of 8.8-16.5GHz,which is 40% relative to the full-mode bandpass filter.Miniaturization of volume.Compare the results of the simulation experiment with the actual product,analyze the cause of the error between the two,and then return to the simulation experiment to verify the factor of the error.On the basis of this half-mode filter,a ferrite block is loaded and a bias magnetic field is added to realize the adjustment of the lower sideband of the band-pass filter,and a magnetically tunable filter is constructed.The tuning range of this magnetically tunable filter reaches 61.5%,which is wider than electrically adjustable and mechanically tunable filters.This filter works at 8.5-12.7GHz,and the cut-off frequency in the passband varies between 8.5-10.1GHz.Then,the split ring was etched between the saw teeth on the conversion structure of the microstrip to the spoof surface plasmon polaritons,and a double-passband filter was designed.The two passbands of this filter are respectively 5-7.8GHz and 9.4-12 GHz.The passband return loss is better than-10 d B.Finally,by etching periodic gaps on the TE₂0 mode substrate integrated waveguide,the design of the high-order mode filter is completed,and the SSPP's first attempt on the high-order mode substrate integrated waveguide is realized.This high-order mode filter works at 8.3-10.9GHz,the insertion loss in band is better than-1.7d B,and the return loss is better than-10 d B.4.Design based on SSPP antenna.First,the principle of the leaky wave antenna is briefly introduced,and the working principle of the SSPP leaky wave antenna is analyzed.A SSPP leaky wave antenna with a coplanar waveguide as a transition structure,a single-sided zigzag conduction band etched on the upper surface as a transmission structure,and eight equally spaced open loops as radiating elements is designed.This antenna works at7-9GHz and has an average in-band gain of 9.2d Bi.This antenna has frequency scanning characteristics in the band.With the change of operating frequency,the main beam direction scanning angle is 36°.This antenna is processed and measured,the error between the simulation experiment and the process measurement is compared,the cause of the error is analyzed,and the conjecture about the error is returned to the simulation experiment to verify the feasibility of designing such an antenna based on the above theory.