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Journal ArticleDOI

Wideband circularly polarized low profile dielectric resonator antenna with meta superstrate for high gain

TL;DR: In this paper, a low profile circularly polarized high directive dielectric Resonator Antenna (DRA) is presented for X-band wireless applications, which is excited by microstrip aperture slot coupling which is employed on the bottom side of the substrate.
Abstract: A low profile circularly polarized high directive Dielectric Resonator Antenna (DRA) is presented for X - band wireless applications. DRA is excited by microstrip aperture slot coupling which is employed on the bottom side of the substrate. Two asymmetric rectangular split rings are created adjacent to the feed line on the substrate to enhance the 3-dB axial ratio bandwidth and impedance bandwidth. Corrugated circular ring shaped single layer double sided meta superstrate is loaded on the DRA to enhance the peak gain to 11.9 dBi. The extracted lumped element model of the Superstrate unit is found to be in concurrence with Electromagnetic (EM) simulations. The proposed geometry offers a 1.1 GHz axial ratio bandwidth with 2.6 GHz impedance bandwidth. A prototype is fabricated and experimentally verified.
Citations
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Journal ArticleDOI
TL;DR: In this article, a wideband hybrid fractal monopole antenna loaded with artifical magnetic conductor (AMC) is proposed, which achieves self-similarity compactness, reduced size and good wideband performances.
Abstract: A wideband hybrid fractal monopole antenna loaded with artifical magnetic conductor (AMC) is proposed. Using a hybrid fractal generator, the monopole antenna achieves self-similarity compactness, reduced size and good wideband performances. The ground is semi-elliptic and has defected steps aiming to improve impedance matching and X-pol. reduction. The AMC reflector has 3 × 3 array of cesaro shaped unit cells looped in a square metallic conductor. The AMC enhances radiation gain with back-lobe reduction. The AMC unit cell produce a 0 0 phase reflection at f AMC = 4.5 GHz and then loaded to optimize antenna performance. To validate the design, a prototype antenna is fabricated and measured. The antenna operates from (3.7–7.0) GHz with 61.68% impedance bandwidth, realized gain of (8.7–13.8) dBi, and radiation efficiency > 82.5%. The proposed antenna leverages on compactness, low-profile AMC height and good boresight radiation gain, which shows its potential for hybrid wireless cellular networks.

17 citations

Journal ArticleDOI
TL;DR: In this article , a dual-band circular polarized (CP) hybrid dielectric resonator antenna (HDRA) with gain enhancement is presented, which is achieved by cutting four corners along the DRA diagonal and adding a metal strip on the corner.
Abstract: This paper presents a dual-band circular polarized (CP) hybrid dielectric resonator antenna (HDRA) with gain enhancement. The fundamental TE111 mode and high-order TE113 mode are excited by the orthogonal CPs in the two frequency bands. This is achieved by cutting four corners along the DRA diagonal and adding a metal strip on the corner. The DRA design procedure is presented to verify its operations. The gain improvement is achieved by loading the water on the top of DRA. This leads to a 1.32 dB improvement on the upper band and have no impact on the lower band. The proposed DRA is fabricated and measured. The results verify its dual-band CP operation at 1.58 GHz (left-hand) and 2.40 GHz (right-band). Two bandwidths of the lower band and upper bands are 20.52% and 21.72%, respectively. The gain improvement is verified from the measurement on both states. The proposed HDRA can be applied for the dual-function communications such as GPS and WLAN.

10 citations

Journal ArticleDOI
25 Aug 2021-Silicon
TL;DR: In this article, a Cylindrical Dielectric Resonator antenna (CDRA) along with silicon based RDR slab is proposed for terahertz (THz) applications.
Abstract: A Cylindrical Dielectric Resonator antenna (CDRA) along with silicon based Rectangular Dielectric Resonator (RDR) slab is proposed in this paper for terahertz (THz) applications. This antenna provides multi-band response at different resonant frequencies. Unique feature of the proposed antenna is, it provides Circular Polarization (CP) behaviour at quad band in the field of THz dielectric resonator antennas and also CP tuning is achieved by varying graphene potential of the antenna. Furthermore this antenna shows both Right Hand CP (RHCP) and Left Hand CP (LHCP) behaviour at different resonant frequencies. A rectangular slab is incorporated with CDRA knows CPDRA to achieve CP response. Results show that a maximum gain of 6.67 dB, maximum radiation efficiency of 89%, 10 dB Impedance Bandwidth (IBW) of 4.66% (8.59-9THz), 2.98% (10.88–11.21THz), 4.83% (14.19–13.52THz) and 5.86% (15.88–16.84), Axial Ratio Bandwidth (ARBW) of 1.83% (8.66–8.82 THz), 2.16% (10.94–11.18), 3.84% (13.26–13.78 THz) and 4.8% (16.04–16.83 THz) is achieved by the combination of CDRA and Rectangular slab. For antenna tunability, the upper layer of CDRA is layered with graphene material and CP performance of antenna is analyzed for different values of graphene chemical potential. This new approach for the tuning and obtained results make the proposed Quad band CP DRA as unique and is suitable for THz applications.

9 citations

Journal ArticleDOI
TL;DR: In this article , a conformal defected ground patch antenna with artificial magnetic conductor (AMC) is introduced for on-body communication, which is designed to operate at 2.45 GHz.
Abstract: ABSTRACT Wireless biotelemetry enables the formation of communication link from living body to an external monitoring device. Isolation of near field electromagnetic (EM) waves from body tissue, and wide bandwidth to avoid frequency detuning in different biological environments are the important parameters of on-body antennas. In this paper, a conformal defected ground patch antenna with artificial magnetic conductor (AMC) is introduced for on-body communication. Initially, a quarter wave wide band antenna with a shorting pin is designed to operate at 2.45 GHz. It resonates effectively on body tissue but most of the near field EM radiations are absorbed by tissue. Poor radiation efficiency of 10% and high specific absorption rate (SAR) value of 7.73 W/Kg were obtained. Thus, to reduce the effect of tissue loading on antenna performance an AMC-based structure is added. Better impedance matching, high efficiency (65%) and directivity (7.3 dBi) is achieved with AMC structure. Furthermore, unidirectional radiation pattern with SAR value of 1.43W/Kg is attained. Wide bandwidth of 600 MHz on phantom enables the antenna to withstand frequency detuning effect due to body postures and movements. Antenna robustness is analysed by bending the structure at different radii along X-axis and Y-axis.

5 citations

Journal ArticleDOI
TL;DR: In this paper , the effects of multiple currents with different directions on the electromagnetic field strength and the focusing zone of the array-structured magnetic stimulation system are studied. And a method is proposed that can predict the spatial distributions of the electric and magnetic fields when currents in different directions are applied to the arraystructured MIMO system.
Abstract: Multi-coil magnetic stimulation has advantages over single-coil magnetic stimulation, such as more accurate targeting and larger stimulation range. In this paper, a 4 × 4 array multichannel magnetic stimulation system based on a submillimeter planar square spiral coil is proposed. The effects of multiple currents with different directions on the electromagnetic field strength and the focusing zone of the array-structured magnetic stimulation system are studied. The spatial distribution characteristics of the electromagnetic field are discussed. In addition, a method is proposed that can predict the spatial distributions of the electric and magnetic fields when currents in different directions are applied to the array-structured magnetic stimulation system. The study results show that in the section of z = 2 μm, the maximum and average magnetic field strengths of the array-structured magnetic stimulation system are 6.39 mT and 2.68 mT, respectively. The maximum and average electric field strengths are 614.7 mV/m and 122.82 mV/m, respectively, where 84.39% of the measured electric field values are greater than 73 mV/m. The average magnetic field strength of the focusing zone, i.e., the zone in between the two coils, is 3.38 mT with a mean square deviation of 0.18. Therefore, the array-structured multi-channel magnetic stimulation system based on a planar square spiral coil can have a small size of 412 μm × 412 μm × 1.7 μm, which helps improving the spatial distribution of electromagnetic field and increase the effectiveness of magnetic stimulation. The main contribution of this paper is a method for designing multichannel micro-magnetic stimulation devices.

1 citations

References
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Book
01 Jan 1982
TL;DR: The most up-to-date resource available on antenna theory and design as mentioned in this paper provides an extended coverage of ABET design procedures and equations making meeting ABET requirements easy and preparing readers for authentic situations in industry.
Abstract: The most-up-to-date resource available on antenna theory and design Expanded coverage of design procedures and equations makes meeting ABET design requirements easy and prepares readers for authentic situations in industry New coverage of microstrip antennas exposes readers to information vital to a wide variety of practical applicationsComputer programs at end of each chapter and the accompanying disk assist in problem solving, design projects and data plotting-- Includes updated material on moment methods, radar cross section, mutual impedances, aperture and horn antennas, and antenna measurements-- Outstanding 3-dimensional illustrations help readers visualize the entire antenna radiation pattern

14,065 citations

01 Jan 2005
TL;DR: The most up-to-date resource available on antenna theory and design is the IEEE 802.11 as mentioned in this paper, which provides detailed coverage of ABET design procedures and equations, making meeting ABET requirements easy and preparing readers for authentic situations in industry.
Abstract: The most-up-to-date resource available on antenna theory and design. Expanded coverage of design procedures and equations makes meeting ABET design requirements easy and prepares readers for authentic situations in industry. New coverage of microstrip antennas exposes readers to information vital to a wide variety of practical applications.Computer programs at end of each chapter and the accompanying disk assist in problem solving, design projects and data plotting.-- Includes updated material on moment methods, radar cross section, mutual impedances, aperture and horn antennas, and antenna measurements.-- Outstanding 3-dimensional illustrations help readers visualize the entire antenna radiation pattern.

2,907 citations

Journal ArticleDOI
TL;DR: In this article, an improved method to retrieve the effective constitutive parameters (permittivity and permeability) of a slab of metamaterial from the measurement of S parameters is proposed.
Abstract: We propose an improved method to retrieve the effective constitutive parameters (permittivity and permeability) of a slab of metamaterial from the measurement of S parameters. Improvements over existing methods include the determination of the first boundary and the thickness of the effective slab, the selection of the correct sign of effective impedance, and a mathematical method to choose the correct branch of the real part of the refractive index. The sensitivity of the effective constitutive parameters to the accuracy of the S parameters is also discussed. The method has been applied to various metamaterials and the successful retrieval results prove its effectiveness and robustness.

1,941 citations

Book ChapterDOI
15 Apr 2005
TL;DR: Linearly and circularly polarized conformal strip-fed dielectric resonator antennas (DRAs) are studied in this article, where a parasitic patch is used to excite a nearly degenerate mode.
Abstract: Linearly and circularly polarized conformal strip-fed dielectric resonator antennas (DRAs) are studied in this article. In the latter case, a parasitic patch is used to excite a nearly degenerate mode. The hemispherical DRA, excited in its fundamental broadside TE111 mode, is used for the demonstration. In the analysis, the mode-matching method is used to obtain the Green's functions, whereas the method of moments is used to solve for the unknown strip currents. In order to solve the singularity problem of the Green's functions, a recurrence technique is used to evaluate the impedance integrals. This greatly increases the numerical efficiency. Measurements were carried out to verify the calculations, with good results. Keywords: circularly polarized antenna; dielectric antennas; mode-matching methods; moment methods; parasitic antennas; resonance

898 citations

Book
01 Jan 2007
Abstract: In recent years, the dielectric resonator antenna (DRA) has emerged as a new and viable alternative to conventional low-gain elements such as dipoles, monopoles, and microstrip patches. This practical resource presents complete, up-to-date details on DRAs in a single volume. The book provides you with clear guidance on the mode of operation and radiation behavior of DRAs, the main methods of excitation, and the major advances in DRA technology. This hands-on reference equips you with simple equations and graphs that help you rapidly design DRAs of spherical, cylindrical, and rectangular shapes, without having to resort to complex analytical or numerical calculations. You find guidelines for designing feeds required to excite the DRAs, such as probes, apertures, and microstrip lines. In addition, the book offers you various techniques for enhancing the bandwidth performance of DRAs for wideband applications. You learn how to design low profile DRAs and DRAs with circular polarization. Several approaches for designing linear and planar DRAs arrays are also considered. Moreover, this comprehensive book provides advice on the fabrication of DRAs and measurement methods used to characterize their performance. Numerous design examples are included to give you a sense of the versatility that DRAs afford.

616 citations