Studies On Phase Switched Screen Based On Artificial Magnetic Conductor

With the continuous development of detection technology,traditional radar stealth technology has gradually failed to meet modern military needs.The radar stealth system based on phase modulation technology moves the energy of the incident electromagnetic wave far enough at the frequency domain so that only a very small part of the energy falls within the receiver's passband,thus showing a very low reflectivity.In addition,the proposal of artificial electromagnetic structures in recent years has attracted more and more attention.Among them,the artificial magnetic conductor structure(AMC)exibits a good characteristic of in-phase reflection at a specific frequency point.It can be used in radar stealth design,which can break through the structural limit of traditional absorbing materials,and has a simple method and is easy to fabricate.The advantages of lower cost and lighter structure have brought new design ideas to the development of radar stealth technology.Therefore,exploring new artificial magnetic conductor structures for improving stealth effect and reducing thickness has certain application value.Based on the above research background,the working principle of the phase-switched screen and the equivalent circuit analysis is introducted firstly,and then introduces the design method of the phase-switched screen based on the artificial magnetic conductor.Based on this theory,the following research contents are mainly carried out in this thesis:Firstly,a new dual-frequency AMC structure is designed,and the equivalent circuit of the dual band AMC is analyzed.By introducing PIN diodes in the structure,a dual band reconfigurable phase-switched screen is realized.By controlling the PIN diode on and off two working states,the reflected phase of the AMC can be freely switched between 0 ° and 180 °,which realizes the absorption of incident electromagnetic waves by the phase-switched screen at 2.38 GHz and 5.25 GHz.Secondly,a new triple band AMC structure is designed,which mainly employs the parasitic capacitance effects of the PIN diode to the structure.The reconfigurable phase-switched screen was carried out by controlling the working state of the PIN diode.In addition,by adjusting the duty cycle of the control sequence of the PIN diode,the absorption effect to the incident waves from the phaseswitched screen at 2.44 GHz,3.96 GHz and 6.05 GHz is achieved.Thirdly,the influence of the phase and amplitude of the AMC structure on the absorption rate of incident electromagnetic waves is further studied.A varactor diode is introduced to design a new AMC structure.By continuously adjusting the parasitic voltage of the varactor diode,a broadband phase-switched screen is realized.Simulation results show that the structure can absorb electromagnetic waves in multiple continuous frequency bands with a bandwidth of 40%.