Design And Application Of Multi-band Frequency Selective Surfaces Based On The Split Ring Resonators (SRR)

Modern information technology and wireless communications network, such as theemergence of4G communications (LTE), wireless application protocol (WAP), indoorwireless LAN (WLAN), Bluetooth system (Bluetooth), Worldwide Interoperability forMicrowave deposit take (WiMax) and global Positioning System (GPS) has entered a era ofrapid development. These developments are popular in subscribers because they greatlyenhance the production capacity and improve people’s living standards significantly.Regarding as an important part of communication systems, frequency selectivity surface (FSS)has attracted more attentions both in military and civilian fields. Meanwhile, in order toimprove the communication quality and anti-interference ability, high selectivity of FSS isalso increasingly important. Based on the author’s works in pursuing the master’s degree, asystematic study of frequency selectivity surface is done. Design and application ofmulti-band frequency selective surface based on split ring resonators (SRR) were furtherexplored.The main researches as follows:(1) A combination of different sizes SRRs multi-band FSS is proposed on the basis ofsummarizing the previous multi-band FSS characteristics. Then multi-band FSS is applied topassive radio frequency identification (RFID). Corresponding resonance frequency band issimulated by electromagnetic simulation software HFSS13.0, and the simulation result isgreat. In addition, the large incidence angle and the polarization stability are also studied. Theresults can fully meet the requirements of large incidence angles and stability under TE modeand TM mode. Therefore this design provides a new design idea for passive RFIDapplications.(2) A triple-band THz frequency selective surface is designed based on non-uniform SRRcell structure. An improved SRR resonance unit that may individually adjustable the centerfrequency of passband is proposed. Considering the key parameters, such as reflectioncoefficient, transmission coefficient, the center frequency and bandwidth, an equivalentcircuit model is given for analysing. The center frequency of0.46THz,0.86THz,1.03THz canbe used in radio astronomy triple-band terahertz FSS. The FSS’s3dB passband ranges are0.34-0.57THz,0.78-0.90THz and1.00-1.10THz, respectively. The relative bandwidths are50%,14%,9.7%.The peak passband reflection coefficients are-37.6dB,-13dB and-19.6dB.The design has a good passband characteristic. A transmission zero at0.94THz is generatedto enhance isolation between the pass bands. Its unit size is0.046λ0*0.065λ0, compared withthe literature results (0.103λ0′*0.103λ0′) were reduced by55.3%and36.9%, indicating that the FSS has the advantage of miniaturization. In addition, the improved SRR resonantstructure also has a large incidence angle. The design is stable within0-60range.(3) A dual-band FSS is designed based on asymmetric opening split ring resonatorposition (A-SRR). This chapter studies the terahertz fields and the electromagnetic propertiesof asymmetric split ring resonators (A-SRR) of a dual-band FSS. By changing the position ofthe opening with the two SRRs, it is possible to observe the changes of transmissioncharacteristics. It is found that the first position of the band is unchanged with the outeropening of ring is fixed. While changing inner opening position, second frequency band ismoving in a certain range. Different opening positions can change the resonant frequency, sothat the frequency is tunable within a certain range. The surface current distribution of A-SRRis viewed by electromagnetic simulation. Combined with the equivalent circuit model, themechanism of the frequency shift on two aspects can be studied from the experimental andtheoretical simulation.(4) Based on the previous research, the transmission characteristic of high-temperaturesuperconducting material in the circuit design is studied. A triple-band high-temperaturesuperconducting filter based on tri-section asymmetric SIR is presented. This study laid thefoundation for the design of high-temperature superconducting material in FSS. A novelasymmetric stepped impedance resonator (ASIR) resonance is presented. How the resonancefrequency changes with varies of the impedance ratio and the electrical length ratio is studied.Then the circuit size parameter is obtained to design a triple-band bandpass filter. Besides thefilter is fabricated and tested. At the same time, its temperature nonlinear effects are alsoresearched for the application of multi-band FSS.