Design Of Reconfigurable Liquid Crystal Antenna

The reconfigurable antenna based on the dielectric anisotropy of liquid crystal,not only has all advantages of the reconfigurable antenna itself,but also the characteristics of the dielectric constant which can be controlled by voltage has made the control scheme simple.In addition,the liquid crystal material can work in an ultra-wide frequency band with a relatively low insertion angle loss.So,it is an excellent choice among many natural materials used in reconfigurable antennas.In this paper,two reconfigurable antennas,Frequency Reconfigurable Microstrip Antenna and pattern reconfigurable holographic antenna,are simulated and designed using liquid crystal material as medium.In the design of Frequency Reconfigurable Microstrip antenna,the packaging structure of LCD cell is fully considered.The influence of the size of LCD cell and the thickness of LCD layer on the echo loss,bandwidth and working frequency of the antenna is analyzed in detail.Finally,the design of a frequency reconfigurable antenna with a center frequency of 2.45 GHz is completed by simulation.Then the design scheme of reconfigurable holographic antenna with directional pattern is elaborated in detail,and the possible factors affecting the working frequency of the holographic antenna,such as impedance unit size,dielectric layer thickness and dielectric constant,are simulated and analyzed in detail.Based on the design theory of the holographic antenna,a holographic antenna with adjustable radiation pattern at 10 GHz operating frequency is designed and analyzed.The performance is verified by simulation and experiment.Finally,the method of adjusting the surface impedance by changing the size of the impedance surface patch element is replaced by the method of adjusting the impedance of the element by changing the dielectric constant of the element.The holographic antenna with 10 GHz operating frequency and controllable radiation pattern is also realized.These two reconfigurable antennas introduced above are both designed by liquid crystal materials,and the dielectric constant of liquid crystal materials varies continuously with the change of applied bias voltage.Therefore,the designed reconfigurable antenna can continuously control the electromagnetic wave in real time.So,the reconfigurable liquid crystal antenna has certain research significance.