High Permittivity Dielectric Substrate Research Articles

Simulation of Wave Propagation in Plasma-Metamaterial Composites Based on Plasma Parameters and Metamaterial Structures

Metamaterial is a left-handed medium used in antenna design to overcome the typical design's larger size and untunable nature. Because of its design with a high permittivity dielectric substrate and some deformation, the wireless sector may be able to solve this difficulty. Metamaterial antennas have a five-fold reduction in size, a higher bandwidth, a wider scanning angle, good beam performance, and electronically controlled targeting. Metamaterials antennas also improve antenna parameters such as frequency generation, gain, and bandwidth. This research aims to suggest the best metamaterials structure for improving antenna performance using plasma as a base. This study used 12 types of plasma with varying plasma frequencies and collision frequencies with four metamaterials structures: 1D-split ring structure, Symmetrical structure, Omega structure, and S structure. Computer Simulation Technology (CST) Studio Suite was used to design and simulate each structure with a sequence of plasma. At frequencies ranging from 1 GHz to 20 GHz, parameters including return loss, gain, radiation pattern, and Voltage Standing Wave Ratio (VSWR) are used to assess an antenna's performance. Due to its electromagnetic qualities, the 1D-split ring construction has a better omnidirectional figure and VSWR value of 1.0039 dB. When all criteria were considered, the best results were obtained when using a 1D-split ring structure of the Plasma 9 (plasma frequency of 3.58528 x1011 rad/s and collision frequency of 1.3349 x109 1/s) produces an efficient return loss, high gain, better VSWR and a better omnidirectional figure among the four structures evaluated.

A High-Permittivity Dielectric Material-Filled SISL Antenna With Cavity Backing

A high-permittivity dielectric material-filled substrate integrated suspended line (SISL) antenna with size reduction is proposed, which provides a novel fixing method for dielectric resonator antenna (DRA). The proposed antenna is based on five substrate layers with two air cavities while the high-permittivity dielectric material is filled with the upper air cavity of the hollowed substrate. So the antenna is self-packaging. The feeding line is on M5 layer and the bottom air cavity affects the resonant frequency much. The expression about the resonant frequencies, the height of the bottom air cavities, and the size of DRA is given. The operating frequency band is from 6.2 to 6.5 GHz and the maximum antenna gain is 6 dBi. In order to reduce the resonant frequency further, a cross strip is added to M2 layer. At last, the impedance bandwidth for |S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> | <; -10 dB is from 5.7 to 6 GHz and the maximum antenna gain is 5.2 dBi.

METAMATERIALS: NEW ASPECTS IN ANTENNA DESIGN

The recent developments of the telecommunication systemstipulate miniaturization and integrating multiple functions is of extreme importance. Particularly devices which are generally used in day to day life like smartphones, tablets, smart TVs, wireless internet devices,mobile communication system, etc. To fulfill this constraint, the handheld devices component should be of more compact, equipped with multiple functions, and operates for a different band of frequencies. Antenna having distinctive features like compact size, conformal to planar and non-planar structures, proficient in operating one or more band of frequencies, etc., is a keyelement in enhancing the performance of wireless communication systems. Currently, there are numerous techniques to address these issues such as high permittivity dielectric substrate,fractal geometry,altering ground plane, and so on. But these techniques have low gain, narrow bandwidth demerits. A novel technique that is of superior attention to antenna researchers is designing antenna by incorporating electromagnetic metamaterial. It consents to change electromagnetic wave propagation resulting in a negative refraction index (NRI). The metamaterials with NRI property performs as filters, radiating element, decoupling network,etc. Hence metamaterial stimulated antennas reduces size as well as enhances antenna parameters. So, in this paper, an effort is made to highlight the implications of metamaterials on antenna design to improve performance and achieve multiband,reconfigurable,miniaturization, isolation enhancement characteristics.

Compact Unidirectional Conformal Antenna Based on Flexible High-Permittivity Custom-Made Substrate for Wearable Wideband Electromagnetic Head Imaging System

An approach toward designing and building of a compact, low-profile, wideband, unidirectional, and conformal imaging antenna for electromagnetic (EM) head imaging systems is presented. The approach includes the realization of a custom-made flexible high-permittivity dielectric substrate to achieve a compact sensing antenna. The developed composite substrate is built using silicon-based poly-di-methyl-siloxane (PDMS) matrix and microscale of aluminium oxide (Al2O3) and graphite (G) powders. Al2O3 and G powders are used as fillers with different weight-ratio to manipulate and control the dielectric properties of the substrate for attaining better matched with the human head and reducing antenna’s physical size while keeping the PDMS flexibility feature. Using the custom-made substrate, a compact, wideband, and unidirectional on-body matched antenna for wearable EM head imaging system is realized. The antenna is configured as a multi-slot planar structure with four shorting pins, working as electric and magnetic dipoles at different frequency bands. The measured reflection coefficient (S11) shows an operating frequency band of 1–4.3 GHz. The time-average power density and the amplitude of the received signal inside the MRI-based realistic head phantom demonstrate a unidirectional propagation and high-fidelity factor (FF) of more than 90%. An array of 13 antennas are fabricated and tested on a realistic 3-D head phantom to verify the imaging capability of the proposed antenna. The reconstructed images of different targets inside the head phantom demonstrate the possibility of utilizing the conformal antenna arrays to detect and locate abnormality inside the brain using multistatic delay-multiply-and-sum beamforming algorithm.

Substrate and Fano Resonance Effects on the Reversal of Optical Binding Force between Plasmonic Cube Dimers

The behavior of Fano resonance and the reversal of near field optical binding force of dimers over different substrates have not been studied so far. Notably, for particle clustering and aggregation, controlling the near filed binding force can be a key factor. In this work, we observe that if the closely located plasmonic cube homodimers over glass or high permittivity dielectric substrate are illuminated with plane wave, no reversal of lateral optical binding force occurs. But if we apply the same set-up over a plasmonic substrate, stable Fano resonance occurs along with the reversal of near field lateral binding force. It is observed that during such Fano resonance, stronger coupling occurs between the dimers and plasmonic substrate along with the strong enhancement of the substrate current. Such binding force reversals of plasmonic cube dimers have been explained based on the observed unusual behavior of optical Lorentz force during the induced stronger Fano resonance and the dipole-dipole resonance. Although previously reported reversals of near field optical binding forces were highly sensitive to particle size/shape (i.e. for heterodimers) and inter-particle distance, our configuration provides much relaxation of those parameters and hence could be verified experimentally with simpler experimental set-ups.

Flexible and compact hybrid metasurfaces for enhanced ultra high field in vivo magnetic resonance imaging

Developments in metamaterials and related structures such as metasurfaces have opened up new possibilities in designing materials and devices with unique properties. Here we report a new hybrid metasurface structure, comprising a two-dimensional metamaterial surface and a very high permittivity dielectric substrate, that has been designed to enhance the local performance of an ultra-high field MRI scanner. This new flexible and compact resonant structure is the first metasurface which can be integrated with multi-element close-fitting receive coil arrays that are used for all clinical MRI scans. We demonstrate the utility of the metasurface acquiring in-vivo human brain images and proton MR spectra with enhanced local sensitivity on a commercial 7 Tesla system.

Substrate-Mediated Broadband Tunability in Plasmonic Resonances of Metal Nanoantennas on Finite High-Permittivity Dielectric Substrate

We investigate the optical response of a gold nanocube antenna supported by a high-permittivity dielectric nanocuboid substrate and propose schemes for broadband tailoring of its plasmonic resonances via alteration in image-charge screening. Based on finite-element-method (FEM) simulations—in agreement with filtered-coupled-dipole-approximations (FCDA)—we explore the tunability and spectral evolution of the substrate-supported nanocube’s hybridized plasmon modes as functions of the relative permittivity and dimensions of the dielectric substrate. Besides numerical calculations, we also derive simple analytical expressions using image-charge theory to readily estimate the resonance spectral shift—gauging the intense particle–substrate interaction—for a substrate-supported nanocube. Strong localized electric field, around the nanocube’s vertices and edges near the substrate, is observed due to the image charges induced in the substrate by the coupled bonding mode arising from hybridization of the primitive dipolar and quadrupolar modes of the nanocube. By introducing slots on the dielectric substrate in the areas around the nanocube’s edges where electric field is highly concentrated, we achieve substrate’s surface-mediated wideband tunability of plasmonic resonance as functions of the geometric parameters of the slots while maintaining the overall dimensions and material of the nanocuboid substrate. These slots enable dynamic tunability of plasmon resonance by placing graphene flakes on them, which facilitates electrical tailoring of nanocube’s plasmon resonance over visible and near-infrared regions. Thus, these proposed schemes would allow one to widely tune the optical responses of any plasmonic nanoantennas using a slotted finite high-permittivity-dielectric substrate for numerous applications in nanophotonic integrated circuits and plasmonic devices.

Compact Dual-Band Proximity-Fed Circularly Polarized Patch Antenna for BDS Applications

AbstractThis paper presents a compact dual-band proximity-fed circularly polarized (CP) patch antenna for BeiDou Navigation Satellite System (BDS) operation at B1 (1,561 MHz) and B3 (1,268 MHz) bands. The antenna aperture is minimized down to 26.6 mm (λ/9 at the B3 band) in diameter and 12 mm (λ/20 at the B3 band) in thickness using high permittivity dielectric substrate and meandered slots. The antenna design features that the resonant frequency in the higher band could be tuned independently by adjusting the branch length and breadth without affecting the lower band. To achieve right-handed CP (RHCP) radiation property, quadrature phase feeding is employed together with a broadband 0°–90° hybrid utilizing a small surface mount LTCC hybrid coupler chip. Experimental results show that the RHCP gain maintains larger than 1.5 dBic and the axial ratio (AR) stays below 3 dB within the B1 and B3 bands. This antenna design is a promising candidate for small BDS arrays as well as other dual-band BDS applications.

COMPACT FOUR-ELEMENT ANTENNA ARRAY DESIGN FOR BEIDOU NAVIGATION SATELLITE SYSTEM APPLICATIONS

In this letter, a compact four-element microstrip patch antenna array for BeiDou navigation satellite system (BDS) operation at the B3 (1268MHz) band is proposed. High permittivity dielectric substrate and slit-loaded microstrip patch are used to reduce the antenna element size down to 40mm × 40mm which implies an aperture size of only λ0/6 × λ0/6 at the B3 band. The right-handed circularly polarized (RHCP) radiation is achieved by connecting two coaxial probes to a 0◦–90◦ stripline hybrid. Four identical antenna elements are distributed with the same polarity and an inter-element separation of 80mm (λ0/3 at the B3 band). The overall size of the antenna array, including the stripline feeding network and supporting ground plane, is only 140mm × 140mm × 5.5mm. A prototype was fabricated and measured to verify the design concept. Simulated and measured results will be presented and discussed, showing that the proposed BDS antenna array is suitable for BDS applications.

Multiple Band-Notched UWB Antenna With Band-Rejected Elements Integrated in the Feed Line

To mitigate potential interferences with coexisting wireless systems operating over 3.3-3.6 GHz, 5.15-5.35 GHz, or 5.725-5.825 GHz bands, four novel band-notched antennas suitable for ultra-wideband (UWB) applications are proposed. These include UWB antennas with a single wide notched band, a single narrow notched band, dual notched bands, and triple notched bands. Each antenna comprises a half-circle shaped patch with an open rectangular slot and a half-circle shaped ground plane. Good band-notched performance is achieved by using high permittivity and low dielectric loss substrate, and inserting quarter-wavelength horizontal/vertical stubs or alternatively embedding quarter-wavelength open-ended slots within the feed line. The results of both simulation and measurement confirm that the gain suppression of the single and multiple band-notched antennas in each desired notched band are over 15 dB and 10 dB , respectively. The radiation pattern of the proposed triple band-notched design is relatively stable across the operating frequency band.

HYBRID MICROSTRIP COMPACT BANDPASS FILTER USING HIGH PERMITTIVITY SUBSTRATE

A four-pole elliptic function compact bandpass fllter is designed by using interdigital hairpin resonator and step-impedance hairpin resonator. The miniaturized band-pass fllter is also implemented using high permittivity dielectric substrate. The full- wave simulator IE3D is used to design the compact hairpin resonator, and to calculate the coupling coe-cient of the basic coupling strictures. The responses of the fabricated fllters using Al2O3 (r = 9:7, Q £ f = 350000GHz) and 0.6Sm(Co1=2Ti1=2)O3-0.4CaTiO3 (r = 37, Q £ f = 43000GHz) dielectric substrates are designed at a center frequency of 2GHz. The size of the compact hairpin fllter using 0.6Sm(Co1=2Ti1=2)O3-0.4CaTiO3 ceramic substrate, as compared to that of a compact hairpin fllter using Al2O3 ceramic substrate, is reduced in size by 45%. The compact size and good agreement have been obtained between simulations and implementation results.

Impedance Analysis of Printed Antenna on Three-Dimensional High-Permittivity Dielectric Substrate Using Mixed-Domain MoM

An integral equation approach with a new solution procedure using moment method (MoM) is applied for the computation of coupled currents on the surface of a printed dipole antenna and inside its high-permittivity three-dimensional dielectric substrate. The main purpose of this study is to validate the accuracy and reliability of the previously proposed MoM procedure by authors for the solution of a coupled volume-surface integral equations system. In continuation of the recent works of authors, a mixed-domain MoM expansion using Legendre polynomial basis function and cubic geometric modeling are adopted to solve the tensor-volume integral equation. In mixed-domain MoM, a combination of entire-domain and sub-domain basis functions, including three-dimensional Legnedre polynomial basis functions with different degrees is utilized for field expansion inside dielectric substrate. In addition, the conventional Rao-Wilton-Glisson (RWG) basis function is employed for electric current expansion over the printed structure. The accuracy of the proposed approach is verified through a comparison with the MoM solutions based on the spectral domain Green's function for infinitely large substrate and the results of FDTD method.

Dual‐band planar rectangular ring microwave bandpass filter using high permittivity substrate

AbstractDual‐band planar bandpass filter, using two microstrip rectangular ring resonators, is proposed for wireless LAN system such as IEEE 802.11 systems (2.4 or 5 GHz). The miniaturized bandpass filter is implemented using a high permittivity dielectric substrate. The full‐wave simulator IE3D is used to design the two coupled rectangular ring resonators. The responses of the implemented filter using Zr0.8Sn0.2TiO4 (εr = 37, tan δ = 0.00012) dielectric substrates are designed at dual‐band frequencies of 2.35 and 4.7 GHz. The compacted size and good agreement have been obtained between simulations and implementation results. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2236–2238, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22677

Compact Multielement Marconi–Franklin Type Printed Antennas for Millimeter Wireless Systems

Two novel Marconi-Franklin type printed antenna arrays, each consisting of three radiating elements arranged in a cascade configuration, are investigated. Both antennas are printed on a single high permittivity dielectric substrate and fed by SMA connectors, although coplanar waveguide (CPW) feed could easily be applied to further allow easier integration into an RF chip module. Two constructed prototypes, suitable for local-multipoint-distribution service operation in the 26-GHz band (25.5-26.5 GHz), are demonstrated. The constructed prototypes show an impedance bandwidth of about 1 GHz and a maximum gain of more than 5 dBi, with small variations (<1.8 dBi), is obtained across the achieved impedance bandwidth. Details of theoretical and experimental results showing impedance and radiation characteristics for both prototype antennas are given and discussed.

Miniaturization microstrip rectangular-ring bandpass filter using high permittivity substrate

A selective band-pass filter with a microstrip rectangular-ring resonator is proposed for wireless LANs such as the IEEE 802.11 systems (2.45 or 5.25 GHz). The miniaturized band-pass filter is implemented using a high-permittivity dielectric substrate. The full-wave simulator IE3D is used to design the single rectangular-ring resonator. The responses of the implemented filters using FR4 (εr = 4.7, tanδ = 0.016) and Sm(Co1/2, Ti1/2)O3 (εr = 25.5, tanδ = 0.00013) dielectric substrates are designed at dual-band frequencies of 2.45 and 5.25 GHz. Compact size and good agreement between the simulation and implementation results are obtained. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 540–543, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21402

Efficient large-domain MoM solutions to electrically large practical EM problems

A numerical method is presented for the analysis and design of a wide variety of electromagnetic (EM) structures consisting of dielectric and conducting parts of arbitrary shapes. The method is based on the integral-equation formulation in frequency domain, and represents a large domain (high-order expansion) Galerkin-type version of the method of moments (MoM). The method is formulated in two versions concerning the type of the equivalence (volume and surface) utilized in the treatment of the dielectric parts of the structure. The generality, versatility, accuracy, and practicality of the method and code are demonstrated on four very diverse, electrically large, and complex EM problems. The examples are: an X-band reflector antenna modeled after a bat's ear, which is about 11/spl lambda//sup 3/ large at X-band; a broad-band (0.5-4.5 GHz) nested array of crossed loaded dipoles; an EM system consisting of a dipole antenna and a human body, and a broad-band (1-5 GHz) microstrip-fed Vivaldi antenna with a high-permittivity dielectric substrate. The central processing unit times with a modest personal computer are on the order of several minutes for a single-frequency application.