The Design And Study Of EBG Antennas

Electromagnetic band gap?EBG?structure,left-handed materials,double negative media,soft/hard surface and other novel artificial electromagnetic metamaterials have been constantly emerged since the 21^st century.Because of their novel electromagnetic properties that the natural materials do not have,they have great application potential in the fields of wireless communications and microwave radio frequency?RF?.EBG structures provide possible solutions to the key technical problems for antenna design owing to their two unique characteristics of frequency and phase band gaps.Therefore,it has great academic value and application prospects to study new EBG structures and explore new areas of EBG structure in antenna design.In this paper,based on the basic characteristics of EBG structure,a variety of high-performance EBG antennas are designed and studied.The simulation and experimental results demonstrate the effectiveness of the design method.Research contents and results are as follows.First of all,as the two basic characteristics of EBG structure,frequency and phase band gaps'formation mechanism has been analyzed by using two methods of electromagnetic theory and numerical simulation.Furthermore,using proper simulation model,the effects of EBG key parameters on the EBG frequency and phase band gaps have been analyzed,which will lay a theoretical foundation for the EBG antenna design subsequently.Secondly,based on the frequency band gap characteristic of EBG structure and to solve the existing technical problems of band-notched antennas,such as large size,a small number of notched bands,wide notched bands and mutual influence of notched bands and so on,an improved SCLV-EBG resonance unit has been designed.The improved SCLV-EBG resonce reduces the size and resonant width of EBG resonator.On this basis,several single band-notched and four band-notched UWB antennas using SCLV-EBG resonators have been designed.By using software simulation and physical testing,the designed antennas can satisfy the requirements of UWB wireless communication system and effectively suppress four bands'signals of WiMAX,dual bands of WLAN and X-band satellite downlink signals.Each resonator has high isolation and in addition,the proposed antenna has high spectral efficiency and stable radiation characteristics.Finally,based on the phase band gap characteristic of EBG structure and to solve the technical problems of EBG phase band gap reflector antennas,such as high cross-section,large reflector plate area,small gain,low polarization conversion efficiency and so on,a C-EBG reflector antenna has firstly been designed which overall cross-section height is only1/11 of operating frequency wavelength.On this basis,dual-layer complementary high-gain EBG reflector antenna is designed which can reduce the size of antenna by 61.93%.And the forward radiation gain of the reflector antenna can also be greatly improved and the increased maximum gain can be 13dB in passband.Then,HP-EBG circularly polarized high-gain reflector antenna has been designed,achieving a circularly polarized radiation of 152MHz in the passband and ensuring the maximum radiation gain above 10dB.Compared to the EBG antennas of existing literature,HP-EBG antenna has the advantages of high gain and high polarization conversion efficiency.At last,the proposed HP-EBG antenna has been fabricated and tested and the test results and simulation results are consistent well which demonstrate the effectiveness of design method.