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Dirac leaky wave antennas
, Article 5th International Conference on Millimeter-Wave and Terahertz Technologies, MMWaTT 2018, 18 December 2018 through 20 December 2018 ; Volume 2018-December , 2019 , Pages 1-5 ; 21570965 (ISSN); 9781538677179 (ISBN) ; Memarian, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Dirac leaky-wave antennas (DLWAs) are derived from photonic crystals exhibiting Dirac cone dispersion around their Γ-point. DLWAs provide high directive beams and continuous frequency beam scanning, non-fluctuating leakage constant and real non-zero Bloch impedance at and around broadside, due to the closed and linear Dirac dispersion relation around broadside. These features, along with their inherent compatibility for higher frequency designs (larger unit cells compared to metamaterials), make DLWAs an ideal candidate for the upper microwave, mm-wave and terahertz frequencies, and for applications such as radar, 5G, spectroscopy, etc. In this review, we cover the recent developments on...
Analytical study of open-stopband suppression in leaky-wave antennas
, Article IEEE Antennas and Wireless Propagation Letters ; Volume 19, Issue 2 , 2020 , Pages 363-367 ; Memarian, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
In the majority of leaky-wave antennas (LWAs), the lack of broadside radiation is due to the existence of an open-stopband (OSB) at broadside. In this letter, we present a study on the OSB suppression in LWAs. In particular, we start from a simple unit cell comprising a planar waveguide having alternating open and short sidewalls. The analytical and simulated band structures testify consistently that OSB suppression can indeed be realized by proper design, analytically studied using mode-matching, and further supported by full-wave simulations. An LWA is then implemented using the substrate integrated waveguide (SIW) technology, which provides interesting features such as a high directive...
Analytical study of Dirac type dispersion in simple periodic waveguide structures for leaky-wave applications
, Article IEEE Access ; Volume 10 , 2022 , Pages 25707-25717 ; 21693536 (ISSN) ; Memarian, M ; Eleftheriades, G. V ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
In this work, we present a study on the existence of Dirac type dispersion in the simplest of periodic metallic waveguide structures. It is shown that periodic repetitions of two dissimilar waveguides (WGs) can be properly designed to lead to a Dirac type dispersion. A simple theory using circuit modeling is presented to find the condition for Dirac point operation. In addition, mode-matching followed by full-wave simulations validate that the band structure matches that of the theory and shows that a Dirac dispersion can be realized. A Dirac Leaky-Wave Antenna (DLWA) is then implemented using this simple arrangement in substrate-integrated-waveguide (SIW) technology. This DLWA has the...
Dirac Leaky Wave Antenna for the Microwave and the mm-Wave Band
, M.Sc. Thesis Sharif University of Technology ; Memarian, Mohammad (Supervisor)
Abstract
Novel Dirac Leaky Wave Antennas (DLWAs) based on Substrate Integrated Waveguide (SIW) are presented in this thesis, for millimeter wave frequencies. These DLWAs provide interesting features such as radiating through broadside, beam scanning and ease in fabrication that are well suited for emerging fifth generation (5G) and IoT applications. In this thesis, it is shown that a Dirac photonic crystal can be realized in SIW technology composed of air columns inside a host SIW waveguide, exhibiting a closed bandgap and linear dispersion around broadside. Phase and attenuation constants are controlled to obtain directive beam and scanning in a wide range of angles (from -30˚ to 20˚). This DLWA...