مبينا آزادخانقاه

Wireless communication systems have gradually used innovative methods to meet the needs of increasing channel capacity an‎d increasing data transfer rates for the development of communication applications. The growth an‎d development of modern telecommunication systems has always been accompanied by the challenge of increasing data transfer rates due to the limited radio spectrum an‎d polarization of waves, even despite the use of very compact coding methods an‎d the use of common channels for data transmission. One of the approaches that has received much attention today is the use of a unique electromagnetic property of waves called orbital angular momentum (OAM). In this thesis, we try to apply the holographic method an‎d aperture field estimation to synthesize a leaky wave antenna an‎d control the radiation behavior of the leaky wave antenna with the help of a suitable design of the hologram surface.In the first step, a holographic leaky wave antenna is designed an‎d synthesized using the holographic method with a square isotropic unit cell. This antenna is fabricated an‎d tested, an‎d good agreement is observed between the simulation an‎d measurement results. The fabricated leaky wave antenna has a conical radiation pattern with angular scanning capability. In the next step, to control the polarization of the radiation beam, an anisotropic unit cell is used to synthesize the leaky wave antenna using the aperture field estimation method. The advantage of using this method is the simultaneous control of the amplitude, phase, an‎d polarization of the aperture field. 3 examples of designing a multi-beam leaky wave antenna using the aperture field estimation method by an anisotropic unit cell with a rectangular an‎d circular slotted patch with the ability to create a vortex an‎d petal-shaped beam are given in the thesis. One of the advantages of producing petal-shaped beams carrying vortex waves is the increase in communication channel capacity an‎d multiplexing. The method of analyzing leaky wave antennas is based on the Floke wave expansion method, an‎d using the analysis method, results can be obtained faster because leaky wave antennas based on impedance surfaces have large dimensions, an‎d simulating these structures in full-wave software is very time-consuming an‎d increases memory consumption.

آنتن موج نشتي، آنتن هولوگرافيك، پرتو گردابي، پرتو گلبرگي شكل، بار توپولوژيكي

Leaky wave antenna, holographic antenna, vortex beam, petal beam, topological charge

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