Dielectric Waveguide Antenna Research Articles

Design and analysis antennas of transverse polarization on the dielectric waveguide

This paper addresses the issue of constructing millimeter band antennas using dielectric waveguide structures. A new type of linear antenna, incorporating metal pins on the side walls of the grooved dielectric waveguide, is proposed for generating polarization perpendicular to the waveguide axis. However, these antennas suffer from the drawback of cross-polarized radiation in directions close to the waveguide axis. To overcome this limitation, a modified antenna design with transverse polarization is introduced, featuring a closed groove waveguide with a longitudinal slot at the top of the wall. The paper provides a comparison between two types of dielectric waveguide antennas: first, waveguide antenna with grooves in the dielectric which results in longitudinal polarization, and second, waveguide antenna with quarter-wavelength pins which results in transverse polarization. Electrodynamic modeling data are provided to demonstrate the effectiveness of the proposed antennas for satellite, 5G antenna, and radar applications. Finally, an antenna of quarter-wavelength pins is proposed with a frequency of 39 GHz, a gain of 19.8 dBi, and a width of the radiation pattern of 3.2∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{\\circ }$$\\end{document}, and a sidelobe level (SLL) of -13.3 dB has been achieved.

Terahertz non-destructive testing of power generator bars with a dielectric waveguide antenna

AbstractTerahertz technologies for non-destructive testing (NDT) are continuing to find their way into the industrial sector in the context of very specific inspection tasks. Part of this development is the capability to adapt terahertz systems in such a way that they can meet the sometimes harsh challenges and requirements of real-world industrial scenarios. One such scenario is the inspection of components with limited available measurement space. In particular, we show here the terahertz NDT inspection of the mica insulation of generator bars of turbogenerators at power plants, where an early on-site detection of defects and cracks in the insulation can be crucial, but where only few centimeters of space between adjacent bars are available. To address this problem, we have developed a measurement system combining a 100 GHz all-electronic terahertz transceiver with a low-loss dielectric waveguide antenna with 90 degree tip. We achieve sub-wavelength image resolution by scanning the waveguide antenna's tip over the surface of the generator bars in a near-field measurement setup. Employing a frequency-modulated continuous wave technique, we obtain depth-resolved, volumetric terahertz images of the objects under test. We discuss here the implementation and performance of the implemented measurement system for terahertz NDT inspection. keywords: terahertz, non-destructive testing, dielectric waveguides, frequency-modulated continuous wave, millimeter waves, power generators

A promising Ka band leaky-wave antenna based on a periodic structure of non-identical irregularities

This paper presents a new periodic grooved dielectric leaky-wave antenna with non-identical irregularities for an extremely high-frequency range capable of performing efficiently in the Ka band through a stable gain, a decrease in the level of the side lobes, and the achievement of a narrower main lobe beam. It consists of a dielectric waveguide antenna placed inside a channelled rectangular metallic waveguide to improve performance. A dielectric rod was used to overcome the losses related to the propagation of electromagnetic waves in metal conductors. A grooved dielectric of a 21-element linear array is used to propose a simple approach for the synthesis of such antennas based on a modified energy method and is fed by a standard waveguide. It was designed and simulated at 37.2 GHz for satellite, 5G antenna, and radar applications. The major novelty of this study is the ability to control the direction of the main lobe through non-identical irregularities in geometric parameters such as the width, height, and distance between each element. Radiation techniques have been extensively studied using simulations. A performance antenna with radiation efficiency of 99.35%, gain of 22 dBi, width of radiation pattern of 3.2 ^{circ }, and side lobe level (SLL) of {-} 18.3 dB has been achieved.

Half‐mode dielectric waveguide antenna fed by a micro‐strip line with air media for endfire radiation

A half-mode dielectric waveguide antenna fed by a micro-strip line with air media is presented. The proposed antenna consists of two dielectric cuboids and an air-substrate micro-strip line. Due to similar modal field configurations, the dielectric cuboids are excited effectively by the micro-strip line, and they work as two half-mode waveguide antennas working on the TM 0 mode. With the length of 6.5 wavelength at the centre frequency of 5 GHz, a measured endfire gain of 12.2 dBi is achieved. The measured 1 and 3-dB gain bandwidths could reach 17 and 46%, respectively. Good matching is obtained over the entire operating band from 3.5 to 6.5 GHz. Compared with the antennas mounted on a large conducting plane, the proposed antenna has the advantages of a high endfire gain, a wide endfire gain bandwidth, and a stable endfire radiation pattern.

A 24 GHz Dual-Polarized and Robust Dielectric Rod Antenna

This paper presents a robust and easy manufacturable dual linear-polarized dielectric waveguide antenna (DRA) for the 24 GHz industrial, scientific, and medical band. Dual-polarized operation is achieved by utilizing a square metal waveguide and a conical horn for exciting the surface wave on a tapered dielectric rod. In order to couple a signal into the square waveguide, an innovative dual-polarized, aperture-coupled microstrip-to-waveguide transition is shown. Additionally, two kinds of radomes, i.e., a foam radome and a half-wave wall monolithic radome are presented to protect the DRA. The antenna achieves a 10 dB bandwidth of 1.7 GHz and a gain of 11.5 dB including losses caused by the transitions and connectors. The sidelobe level and the cross-polarization level are lower than −25 and −26 dB, respectively. Designs and measurement results of all components are described in detail in this paper.

Planar Excitation of Dielectric Waveguide Antenna for Broadband and High-Gain Application

In this letter, a linearly tapered dielectric waveguide antenna with planar substrate integrated waveguide (SIW) feeding is presented for Ku-band (12-18 GHz) application. To make the feeding network planar, the SIW and central part of antenna are fabricated on a single substrate. Two metal strips are mounted on each top and bottom side of the central part of the antenna element for matching purpose. The antenna is designed and optimized using Ansoft HFSS. The optimized prototype is fabricated and measured. An endfire radiation pattern is achieved with low sidelobe (around 12 dB) and cross-polarization (around 20 dB) level in both E- and H-planes. The measured impedance bandwidth and maximum gain are 33.3% (11.5-16.1 GHz) and 12.4 dBi, respectively.

Harvesting, Coupling, and Control of Single-Exciton Coherences in Photonic Waveguide Antennas.

We perform coherent nonlinear spectroscopy of individual excitons strongly confined in single InAs quantum dots (QDs). The retrieval of their intrinsically weak four-wave mixing (FWM) response is enabled by a one-dimensional dielectric waveguide antenna. Compared to a similar QD embedded in bulk media, the FWM detection sensitivity is enhanced by up to 4 orders of magnitude, over a broad operation bandwidth. Three-beam FWM is employed to investigate coherence and population dynamics within individual QD transitions. We retrieve their homogenous dephasing in a presence of low-frequency spectral wandering. Two-dimensional FWM reveals off-resonant Förster coupling between a pair of distinct QDs embedded in the antenna. We also detect a higher order QD nonlinearity (six-wave mixing) and use it to coherently control the FWM transient. Waveguide antennas enable us to conceive multicolor coherent manipulation schemes of individual emitters.

Ka-band Dielectric Waveguide Antenna Array for Millimeter Wave Active Imaging System

Ka-band compact dielectric waveguide antenna array for active imaging system is given. Antenna array with WR28 metal waveguide direct feeding is specially designed with small size, high gain, good radiation pattern, easy realization, low insertion loss and low mutual coupling. One practical antenna array for 3-D active imaging system is shown with theoretic analysis and experimental results. The mutual coupling of transmitting and receiving units is less than -30dB, the gain from 26.5GHz to 40GHz is (12-16) dB. The results in this paper provide guidelines for the designing of millimeter wave dielectric waveguide antenna array.