Research On Applications Of EBG For RCS Reduction And Miniaturization Of Antenna

Electromagnetic band gap (EBG) is an artificial periodic structure that is verycompact. It exhibits unique electromagnetic characteristics, namely surface wavesuppression and in-phase reflection for incident plane waves. It also supports slow wavepropagation. In recent years, EBG has found many useful applications in antennas andmicrowave circuits. It can realize high performance antenna and microwavecomponents. It also can be applied in antenna stealth.In this dissertation, the equivalent circuit models, HFSS simulations andmeasurement methods are introduced to analyze the EBG structures’ surface wavesuppression bandgap, respectively. The electromagnetic theory and HFSS simulationsare discussed to analyze the reflection phase bandgap, respectively. The antennascattering mechanism is also introduced. The major works are outlined as follows:Firstly, the relationships between the reflection phase band gap and the structureparameters are discussed. The EBG structure is added on the waveguide slot arrayantenna. The in-band RCS of the waveguide slot array antenna is reduced. At the sametime, the radiation performances are preserved. Furthermore, a dual-band HIS isproposed and added around the dual-band microstrip antenna. The RCS of thedual-band antenna is reduced in working frequency bands.Secondly, the UC-EM model of the Mushroom-like EBG structure is set up. Thewavelength of slow wave at4.5GHz is determined. The EBG structure is used as theground plane to realize a miniaturized microstrip antenna. The overall antenna area andthe radiation patch area are reduced by83.34%and59.5%, respectively. The bandwidthis also improved.Lastly, a novel miniaturized EBG is proposed that has a stable resonant frequencywith respect to variation of incident angles for TE and TM-polarised plane waves. Theunit cell is incorporated with spiral-shaped capacitor and meandered line inductor. Themetal patches are connected by metal vias to a solid conducting sheet. For the same sizeof unit cell, the center frequency of-10dB frequency bandgap and resonant frequency ofreflection phase is reduced by57.2%and46.25%compared to that of theMushroom-like EBG, relatively.