Research And Design Of Reconfigurable Frequency Selective Surface And Antenna

In recent years,with the rapid upgrading of wireless communication systems,the types and numbers of electronic devices have developed greatly,and the space requirements for the system platform have become higher and higher.Therefore,the reconfigurable technology has gradually developed into a hot issue in the field of wireless communications.Reconfigurable technology has a large application space in electromagnetic metasurfaces,antennas,filters and other fields.It can further optimize the functions of antennas and microwave circuits to meet the requirements of multi-function and integration.This thesis is based on loading active devices and using liquid metal,a variety of reconfigurable frequency selective surfaces and reconfigurable antennas have been designed.The main content can be divided into three parts:1.Four types of active reconfigurable frequency selection surfaces are designed: a bandpass frequency reconfigurable metasurface with continuously adjustable function in S and C bands.By adjusting the capacitance value of the capacitor in the range of 0.45 p F-2p F,continuous band-pass tuning is achieved in the S and C bands;a frequency selection surfaces with reconfigurable and higher angular stability in the C,X,and Ku bands is realized,but it has the disadvantage that the number of loaded diodes is not conducive to practical applications;A reconfigurable frequency selective surface with a wide reconfigurable passband and high angular stability.Adjustable bandpass characteristics can be realized by loading varactor diodes.Improve the angular stability by inserting metal through holes in the dielectric plate.The proposed RFSS can achieve stable transmission of electromagnetic waves in the continuously adjustable broadband range of C,X,and Ku bands by changing the capacitance of the loaded varactor diode when the incident angle is in the range of 0° to60°;Multifunctional reconfigurable frequency selection surface.It can be realized that at 4GHz,the state of the PIN switch is changed,and the band pass and band resistance can be switched;In addition,when the PIN is in the conducting state,the bias voltage is changed to change the capacitance of the loaded varactor diode to realize the reconfigurable function of the band-pass frequency band in the range of 1.37GHz-5.66 GHz.2.A polarization reconfigurable high-gain antenna based on PIN diode loading that can be applied to 5G mobile communication applications is proposed.The antenna's working frequency is 5GHz,and it realizes three reconfigurable functions: linear polarization,lefthand circular polarization and right-hand circular polarization.Reconfigurable function of this state.In the three states of the antenna,each has a better cross-polarization ratio,frontto-back ratio and higher gain.3.A terminal frequency reconfigurable antenna based on liquid metal control is proposed.The length of the liquid metal in the pipeline is controlled by a micro pump,and four single antennas working at 5 GHz,4.2 GHz,3.3 GHz,and 2.4 GHz are connected.This will change the actual radiation length of the antenna and carry out the reconfigurable frequency design of the antenna.By connecting different antennas,the working state of the 2.4GHz MIMO antenna and the low frequency working state of 0.85 GHz and 0.65 GHz can be realized.