| The rapid development of modern communication technology in the field of mobile communications and military,has put forward more innovative solutions for the new generation antenna design.The common challenge faced by antenna designers is to further accelerate the research of new antenna forms while maintaining the required radiation characteristics,and to provide excellent solutions to existing mobile communication and military problems.Antennas in the field of communication technology often have clear requirements for parameters such as gain,profile,weight,etc.The regulations in the field of military technology are more stringent.It is also necessary to consider whether the antenna has radio frequency stealth and whether it can conform to irregular surfaces.In the traditional solutions,most of the reflector antennas,array antennas,and plane reflection arrays are used,but they have their own advantages and disadvantages.With continuous innovation and improvement,the artificially modulated impedance surface antenna(AMSIA)has attracted great attention because of low profile,easy shape and feed.Simple electricity,good control of polarization and radiation direction characteristics of AMSIA have received strong attention and research from scientists at home and abroad,thus become the mainstream research direction.The AMSIA studied in this thesis is a branch of optical holographic antenna applied in the field of microwave and millimeter wave.Its analysis and design are based on a large number of research results at home and abroad.Specifically,the thesis uses MATLAB 2017 b and Ansoft HFSS 15.0 for joint simulation.Firstly,the realization mechanism of the optical holography principle in the submillimeter wave band is explained.The conversion principle of surface wave to leaky wave is analyzed,and the periodic modulation leaky wave is described.Then,according to the theoretical description,implementation steps,specific operations and simulation analysis,the holographic artificial impedance modulation surface,the conformal artificial impedance modulation surface,and the tensor artificial modulation impedance surface are successively implemented.First,the scalar impedance modulation surface feeding network is simple,which can convert surface waves into leaky waves into the space and obtain higher gain.This part not only uses the eigenmode of HFSS to solve,but also extracts the unit of scalar impedance surface.A scalar impedance surface antenna was constructed,and various methods for extracting surface impedance were described.Then a scalar artificial impedance surface antenna with a center frequency of 10 GHz,an exit angle of 43°,and a gain of about 23 d Bi was completed.Secondly,the conformal artificial impedance surface antenna can be used to reorient the incident wave to control the direction of the outgoing beam.A conformal artificial impedance operating at 10 GHz with exit angle of 0° and a peak gain of 18.43 d Bi is designed.This part not only introduces the method of converting 3D strip into 2D rectangular grid,but also the relationship between 3D coordinate system and 2D coordinate system in impedance modulation process in surface antenna.The modulation formula of the conformal impedance surface is finally obtained by using the correspondence between the developed plane variables.Thirdly,because the tensor artificial impedance surface can be anisotropically processed by the unit structure and flexibly control the polarization of the surface,based on this,the equivalent circuit method of PATEL to extract the tensor impedance unit is introduced,and a center is designed.The frequency is at 9.83 GHz and the peak gain in the 47° direction reaches the LHCP tensor impedance surface of 18.5 d Bi.By reading this thesis,it is possible for the latecomers to quickly understand and learn the current international theory and research methods of the artificial impedance modulation surface,which provides a good platform for the latecomers. |
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