Antenna Engineering Research Articles

A Review of Various Multi-Frequency Antenna Design Techniques

Background/Objectives: The paper caters to the need for multi banding of Micro Strip Antennas (MSAs), that has been well recognized as one of the major research issue in antenna engineering in 21st century. Methods/Statistical analysis: Wireless applications, supporting multiband standards have put new demands on antennas related to bandwidth, gain, size and efficiency. Recent efforts by several researchers around the world to achieve multiband geometry have led to an emergence of new and innovative antenna designs which are presented in this paper. Findings: This paper gives a comprehensive review of various techniques to design compact, multiband planar antennas for wireless devices and applications. The theoretical concept to achieve multi frequency antenna along with related issues for designing have been generally and briefly discussed. Especially, the design examples, some of which are published in literature are presented for the illustration purpose. Recent techniques like EBG/AMC, SRR/CRR, FSS and DGS have also been included in this review. Application/Improvements: These antennas find their extensive use in different wireless applications in the field of communication, medical stream and satellite communication. The innovations in technology have been presented which includes improved antenna designs using better techniques for enhanced performance in the respective fields.

Photosynthetic antenna engineering to improve crop yields.

Evidence shows that decreasing the light-harvesting antenna size of the photosystems in tobacco helps to increase the photosynthetic productivity and plant canopy biomass accumulation under high-density cultivation conditions. Decreasing, or truncating, the chlorophyll antenna size of the photosystems can theoretically improve photosynthetic solar energy conversion efficiency and productivity in mass cultures of algae or plants by up to threefold. A Truncated Light-harvesting chlorophyll Antenna size (TLA), in all classes of photosynthetic organisms, would help to alleviate excess absorption of sunlight and the ensuing wasteful non-photochemical dissipation of excitation energy. Thus, solar-to-biomass energy conversion efficiency and photosynthetic productivity in high-density culturescan be increased. Applicability of the TLA concept was previously shown in green microalgae and cyanobacteria, but it has not yet been demonstrated in crop plants. In this work, the TLA concept was applied in high-density tobacco canopies. The work showed a 25% improvement in stem and leaf biomass accumulation for the TLA tobacco canopies over that measured with their wild-type counterparts grown under the same ambient conditions. Distinct canopy appearance differences are described between the TLA and wild type tobacco plants. Findings are discussed in terms of concept application to crop plants, leading to significant improvements in agronomy, agricultural productivity, and application of photosynthesis for the generation of commodity products in crop leaves.

A Broadband Left-Handed Metamaterial Microstrip Antenna with Double-Fractal Layers

This paper proposes a microstrip patch antenna based on the left-handed metamaterial concept, using planar periodic geometry, which results in improved characteristics. This periodic geometry is derived from fractal shapes, which have been widely used in antenna engineering. The metamaterial property was obtained as a result of the double-fractal structure on both the upper and the bottom sides of the antenna. The final structure has been optimized to enhance bandwidth, gain, and radiation characteristics of the microstrip antenna. This combination significantly improved antenna performance; our design could support an ultrawide bandwidth ranging from 4.1 to 19.4 GHz, demonstrating higher gain with an average value of 6 dBi over the frequency range and a peak of 10.9 dBi and a radiation capability directed in the horizontal plane of the antenna.

Dielectric resonator antennas: An application oriented survey

This survey article outlines a comprehensive investigation of research carried out on dielectric resonator antennas (DRAs) in the last three and half decades, in an application-oriented approach. DRAs have created a remarkable position in antenna engineering for their adept characteristics like high efficiency, low loss, wide bandwidth, compact size, 3-dimensional modeling flexibility, etc. The use of DRAs for different commercial and defense applications associated with the wireless communication is highlighted in this article. To make a smooth and effective survey article, all the application-oriented DRAs available in the open literature are classified in five different categories like microwave bands, specific frequency, technology, millimeter-wave, and miscellaneous types. The ultimate aims of this review article are as follows: (i) highlights the usability of DRAs for different commercial and defense applications, (ii) helpful for the antenna industries/manufacturers to find out the best DRA for any specific application as per their requirement, and (iii) points out research gap in some application domains which will be quite helpful for future antenna researchers. In the authors' opinion, this survey may be helpful to DRA researchers as such a survey process is not available in the open literature.

Modeling of electromagnetic band gap structures: A review

This article represents a comprehensive review of the research carried out on analytical and numerical methods modeling of electromagnetic band-gap (EBG) structures used in around last two decades. Because of the unique characteristics of the surface wave reduction as well as perfect magnetic conductor (PMC) like behavior, the EBG structures have created their separate existence in antenna engineering society. These structures are being widely used in designing of several microwave planar circuits including printed antennas, printed microwave filters, etc. The purpose of this article is to present an inclusive review of analytical methods as well as numerical methods in the context of modeling of EBG-structures. Such a review process is rarely carried out in the open literature to the best of authors' knowledge. The review exercise might be helpful to the researchers working on modeling of EBG-structures as well as of EBG-structured printed antennas, microwave planar filters, etc.

Design and simulation of equilateral triangular microstrip antenna using particle swarm optimization (PSO) and advanced particle swarm optimization (APSO)

In this paper a new design is proposed in microstrip antenna family. In this paper, a review design of microstrip antenna design using particle swarm optimization (PSO) and advanced particle swarm optimization (APSO) has been presented which optimizes the parameters and both results are compared. This technique helps antenna engineers to design, analyze, and simulate antenna efficiently and effectively. An advanced PSO driven antenna has been developed to calculate resonant frequency of slit-cut stacked equilateral triangular microstrip antenna. The paper presents simplicity, accuracy and comparison of result between PSO and APSO.

Multi-objective optimization of expensive electromagnetic simulation models

Vast majority of practical engineering design problems require simultaneous handling of several criteria. For the sake of simplicity and through a priori preference articulation one can turn many design tasks into single-objective problems that can be handled using conventional numerical optimization routines. However, in some situations, acquiring comprehensive knowledge about the system at hand, in particular, about possible trade-offs between conflicting objectives may be necessary. This calls for multi-objective optimization that aims at identifying a set of alternative, Pareto-optimal designs. The most popular solution approaches include population-based metaheuristics. Unfortunately, such methods are not practical for problems involving expensive computational models. This is particularly the case for microwave and antenna engineering where design reliability requires utilization of CPU-intensive electromagnetic (EM) analysis. In this work, we discuss methodologies for expedited multi-objective design optimization of expensive EM simulation models. The solution approaches that we present here rely on surrogate-based optimization (SBO) paradigm, where the design speedup is obtained by shifting the optimization burden into a cheap replacement model (the surrogate). The latter is utilized for generating the initial approximation of the Pareto front representation as well as further front refinement (to elevate it to the high-fidelity EM simulation model level). We demonstrate several application case studies, including a wideband matching transformer, a dielectric resonator antenna and an ultra-wideband monopole antenna. Dimensionality of the design spaces in the considered examples vary from six to fifteen, and the design optimization cost is about one hundred of high-fidelity EM simulations of the respective structure, which is extremely low given the problem complexity.

Small Printed Tri-band Antenna with Reduced Ground-plane Effect

Abstract This paper presents a small printed tri-band antenna with a reduced ground-plane effect for WLAN/M-WIMAX applications. The radiator and ground plane of the antenna are etched on a printed circuit board with an overall size of 25×24.5×0.762 mm3. A rectangular notch and a circular slot are cut from the radiator while an asymmetrical strip is attached to the radiator. The simulation and measurement suggest that the printed antenna achieves three operating bandwidths of 2.4–2.484 GHz and 5.15–5.35 GHz for WLAN, 3.3–3.69 GHz for M-WIMAX for a 10-dB return loss, and high gains on Y-Z plane of 2.1, 3.3 and 4.8 dB at 2.4, 3.5 and 5.2 GHz, respectively. In particular, the ground-plane effect on impedance performance is significantly reduced by minimising the size of the ground plane and then by cutting a notch and a circular slot from the radiator because the electric currents on the ground plane are significantly suppressed at all the operating bandwidths. In addition, a study on the geometrical and electrical parameters of the proposed antenna may be a useful reference for antenna engineers.

Link Analysis of High-Throughput Spacecraft Communication Systems for Future Science Missions Antenna Applications Corner

In this issue’s “Antenna Applications Corner” column, author Rainee N. Simons from NASA’s Glenn Research Center describes link analysis of high-throughput satellite communication systems and its impact on the antenna design and performance for future low Earth orbit (LEO) satellites being planned by NASA. The article discusses two scenarios: 1) the first one employs a high data rate link between LEO and ground via relay satellites in geostationary orbit, and 2) the second one is a high data rate link from LEO directly to ground. Link analysis and data rates are shown for both cases, taking into account effective isotropic radiated power, waveforms, elevation angle, path losses, and the receiving antenna gain/system temperature. This article is useful for system and antenna engineers working on link analysis and hardware trades.

Coupled structural-electromagnetic modeling and analysis of hexagonal active phased array antennas with random errors

The structural and electromagnetic performances of planar hexagonal active phased array antenna (APAA) are degraded because of the position errors of radiating elements caused by manufacturing processing, assembly and environment loads. It seriously restricts the realization of high performances of phased array antenna. By considering the changeable mutual coupling parameters and introducing the structural distortion factor into the antenna pattern function, the coupled structural-electromagnetic model of planar hexagonal array antennas was developed. The quantitative relationship between the structural error and the electromagnetic performances of antenna was discussed with consideration of the mutual coupling. The influence of the plane assembling accuracy and flatness on antenna performance was analyzed with the change in the number of array elements. The presented valuable simulation results could be used in antenna engineering to provide guidance for the antenna designers to set the optimal performance-driven tolerance in manufacturing antenna.

Imaging and Steering Unidirectional Emission from Nanoantenna Array Metasurfaces

In radiofrequency antenna engineering, the array factor made long-distance communication with steerable transmission and receiving possible. At optical frequencies, low-loss signal transmission via free space by using nanoantennas is still in its infancy. Here, we suggest applying the array factor to the optical frequency regime by shaping the radiation pattern of plasmonic metasurfaces featuring nanoantenna arrays. We arrange dipolar gold nanoantennas operating at 785 nm wavelength in wavelength-sized arrays and control the phase that drives the antenna elements. We obtain collimated and unidirectional radiation from this metasurface upon illumination with circularly polarized light, which is not prone to major losses as in common plasmonic waveguide structures. We furthermore demonstrate switching the unidirectional emission to opposite directions with additional beamsteering by modifying the array factor. Our experiment corroborates the evidence for spin–orbit coupling between the helicity of light and suitably designed plasmonic metasurfaces, which can exhibit the spin-Hall effect for light.

FPC Antennas: C-band point-to-point communication systems

A high-gain wide-band Fabry-Perot cavity (FPC) antenna is presented for C-band point-to-point communication systems. The proposed antenna utilizes a broadband aperture-coupled microstrip antenna (ACMA) as the source and multilayer frequency-selective surfaces (FSSs) as the superstrate. The experimental result shows that the proposed antenna achieves an impedance band from 4 to 5.4 GHz (30%) for ${\rm S}_{{\rm 11}}{\rm \leq-10}$ dB. The wide band is obtained through the merging of different resonance frequencies due to the patch, the coupling aperture, and the superstrate layer. The antenna also facilitates an enhanced broadside gain up to 14.2 dBi at 4.8 GHz with variations of less than 4 dB throughout the operating band by loading three layers of FSS superstrate. Furthermore, a parametric study is performed to provide antenna engineers with information about the design.

Cavity-excited Huygens' metasurface antennas for near-unity aperture illumination efficiency from arbitrarily large apertures.

One of the long-standing problems in antenna engineering is the realization of highly directive beams using low-profile devices. In this paper, we provide a solution to this problem by means of Huygens' metasurfaces (HMSs), based on the equivalence principle. This principle states that a given excitation can be transformed to a desirable aperture field by inducing suitable electric and (equivalent) magnetic surface currents. Building on this concept, we propose and demonstrate cavity-excited HMS antennas, where the single-source-fed cavity is designed to optimize aperture illumination, while the HMS facilitates the current distribution that ensures phase purity of aperture fields. The HMS breaks the coupling between the excitation and radiation spectra typical to standard partially reflecting surfaces, allowing tailoring of the aperture properties to produce a desirable radiation pattern, without incurring edge-taper losses. The proposed low-profile design yields near-unity aperture illumination efficiencies from arbitrarily large apertures, offering new capabilities for microwave, terahertz and optical radiators.

Expedited Dimension Scaling of Microwave and Antenna Structures Using Inverse Surrogates

Re-designing circuits for various sets of performance specifications is an important problem in microwave and antenna engineering. Unfortunately, this is a difficult task that is normally realized as a separate design process, which is often as expensive (in computational terms) as obtaining the original design. In this work, we consider the application of inverse surrogate modeling for fast geometry scaling of microwave and antenna structures. Computational efficiency of the discussed procedure is ensured by representing the structure at the low-fidelity model level. The explicit relation between design specifications (here, operating frequency) of the structure and its geometry dimensions is determined based on a set of predetermined reference designs. Subsequently, the model is corrected to elevate the re-designed geometry to the high-fidelity electromagnetic (EM) model level. Our approach is demonstrated through a compact rat-race coupler and a patch antenna with enhanced bandwidth.

Итерационные методы оценки поля излучения бортовых щелевых антенн

The rigorous electromagnetic formulation of the problem to define the pattern of slot antennas mounted on aircraft is used Fredholm’s integral equation of II kind. For calculation of the slot antenna far-field pattern on perpendicular plane to aircraft axis is used an asymptotic correspondence of 3D and 2D problems in antenna engineering. We assume that slot antenna axis is parallel to aircraft axis. It is shown such correspondence is increasing the abilities of modeling the radiation pattern of slot antennas and arrays. High-precision Gauss quadrature formulas is used for matrix elements calculation. Turn from direct numerical tecniques of the integral equation solving to iterative procedures requires preliminary analysis of the using methods, especially for convergence of largescale problems. On the base of multiple numerical experience for solving some widely-known test poblems we defined the most methods for solving such problems – conjugate gradients squared method and generalized minimum residual method. Numerical result shows that patterns of the aircraft slot antennas have a large number of directional nulls.

Ground plane booster antenna technology using a self‐diplexed matching network for multiband operation

ABSTRACTThe non‐stop evolution of wireless handset devices together with the apparition of new communication standards encourage antenna engineers to design new concepts able to satisfy the current market demands. The objective of the present article is to provide a radiating system for a smartphone platform capable of operating at the most common mobile frequency bands (LTE‐800, GSM‐850, GSM‐900, LTE‐1700, LTE‐1800/GSM‐1800, GSM‐1900, LTE‐2100/UMTS, and LTE‐2300). The proposed design is based on a non‐resonant element only requiring a volume of 250 mm3 able to provide radiation thanks to the ground plane and a self‐diplexed matching network. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:453–461, 2016

Implementation of Soft Computing Optimization Techniques in Antenna Engineering [Antenna Applications Corner

Editor's Note In this issue's Antenna Applications Corner column, authors Balamati Choudhury, Susan Thomas, and Rakesh Mohan Jha describe various techniques available for soft computing to tackle large, nonlinear problems in electromagnetics and antenna designs. Soft computing techniques differ from hard computational methods, and they do not rely on stringent mathematical formulations but instead are based on imitating biological systems such as human intelligence, genetic inheritance, and foraging behavior. These methods are useful in adaptive antenna arrays, metamaterials, and space/air vehicles.

Bridging the Gap between RF and Optical Patch Antenna Analysis via the Cavity Model.

Although optical antennas with a variety of shapes and for a variety of applications have been proposed and studied, they are still in their infancy compared to their radio frequency (rf) counterparts. Optical antennas have mainly utilized the geometrical attributes of rf antennas rather than the analysis tools that have been the source of intuition for antenna engineers in rf. This study intends to narrow the gap of experience and intuition in the design of optical patch antennas by introducing an easy-to-understand and easy-to-implement analysis tool in rf, namely, the cavity model, into the optical regime. The importance of this approach is not only its simplicity in understanding and implementation but also its applicability to a broad class of patch antennas and, more importantly, its ability to provide the intuition needed to predict the outcome without going through the trial-and-error simulations with no or little intuitive guidance by the user.

Optimization method of thinning MIMO radar arrays based on almost difference sets

An optimization method of thinning multiple-input multiple-output(MIMO) radar arrays based on almost difference sets (ADS) is presented to avoid the shortage in quantity of cyclic difference sets (CDS)-based array configurations caused by the strict construction conditions of CDS. This method can analytically determine the element locations of transmitting and receiving arrays, and a priori estimate the upper bound of virtual array pattern sidelobes. Considering the advantages of better sidelobe performances with respect to random arrays and richer configuration choices with respect to CDS-based MIMO arrays, the proposed method is of common use in antenna engineering. Extensive simulations are performed to verify the effectiveness of the proposed method.

Performance of Epidermal RFID Dual-loop Tag and On-Skin Retuning

Originally introduced by the material science community, the epidermal electronics is now collecting interest also among antenna engineers for the potentiality to achieve thin and flexible sensing transponders that are suitable to application over the epidermis. Unlike conventional wearable antennas, which are generally decoupled by the lossy human body by means of spacers or shielding sheets, epidermal tags need to be placed at a very close touch with the skin thus providing poor communication capabilities. This paper investigates, by means of a detailed numerical and experimental study, the performance of an epidermal dual-loop tag for UHF radiofrequency identification (RFID) depending on the specific placement over different parts of the human body and for a variety of volunteers. An on-body tuning mechanism is also introduced and demonstrated in real applications at the purpose to improve the tag response and hence to enable the use of a same tag layout for all the UHF-RFID bands and for several placement loci.