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Search results for: ANTENNA%20MINIATURIZATION
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Some Aspects in the Model of a Wire Antenna by Using the Mathcad Language
PublicationW artykule omówiono możliwość modelowania anteny prętowej przy wykorzystaniu programu Mathcad. Przedstawiono sposób rozwiązywania równania różniczkowo-całkowego na przykładzie równania Pocklingtona. Artykuł zawiera szczegółowy opis modelu, uzyskane wyniki obliczeniowe i wnioski na temat użyteczności metody i problemów związanych ze zbieżnością zastosowanych algorytmów numerycznych.
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A Concept and Design Optimization of Compact Planar UWB Monopole Antenna
PublicationA novel structure concept of a compact UWB monopole antenna is introduced together with a low-cost design optimization procedure. Reduced footprint is achieved by introduction of a protruded ground plane for current path increase and a matching transformer to ensure wideband impedance matching. All geometrical parameters of the structure are optimized simultaneously by means of surrogate based optimization involving variable-fidelity...
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Adaptive Wavelet-Based Correction of Non-Anechoic Antenna Measurements
PublicationNon-anechoic measurements represent an affordable alternative to evaluation of antenna performance in expensive, dedicated facilities. Due to interferences and noise from external sources of EM radiation, far-field results obtained in non-ideal conditions require additional post-processing. Conventional correction algorithms rely on manual tuning of parameters, which make them unsuitable for reliable testing of prototypes. In this...
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Review of Recent Advancement on Nature/Bio-inspired Antenna Designs
PublicationThis article presents an extensive examination of antennas rooted in nature and biology, showcasing their remarkable performance across a wide spectrum of frequencies—from microwave to terahertz. The limitations of traditional antenna design have become increasingly evident in the face of burgeoning demands for novel communication technologies. Conventional analytical-equation-based approaches struggle to deliver the combined performance...
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Detection and Mitigation of GPS Spoofing Based on Antenna Array Processing
PublicationIn this article authors present an application of spatial processing methods for GPS spoofing detection and mitigation. In the first part of this article, a spoofing detection method, based on phase delay measurements, is proposed. Accuracy and precision of phase delay estimation is assessed for various qualities of received signal. Spoofing detection thresholds are determined. Efficiency of this method is evaluated in terms of...
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Influence of Dielectric Overlay Dimensions on Performance of Miniaturized ESPAR Antenna
PublicationIn this paper, the influence of dielectric overlay size on miniaturized ESPAR antenna performance has been investigated. The dielectric overlay’s main function is antenna’s size reduction but it can also be used to modify its radiation pattern. This creates the possibility of easy adopting antenna parameters to different applications by swapping used overlay. In particular, the lowering of antenna’s main beam elevation direction...
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Dimensionality-Reduced Antenna Modeling with Stochastically Established Constrained Domain
PublicationOver the recent years, surrogate modeling methods have become increasingly widespread in the design of contemporary antenna systems. On the one hand, it is associated with a growing awareness of numerical optimization, instrumental in achieving high-performance structures. On the other hand, considerable computational expenses incurred by massive full-wave electromagnetic (EM) analyses, routinely employed as a major design tool,...
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On geometry parameterization for simulation-driven design closure of antenna structures
PublicationFull-wave electromagnetic (EM) simulation tools have become ubiquitous in antenna design, especially final tuning of geometry parameters. From the reliability standpoint, the recommended realization of EM-driven design is through rigorous numerical optimization. It is a challenging endeavor with the major issues related to the high computational cost of the process, but also the necessity of handling several objectives and constraints...
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Tolerance Optimization of Antenna Structures by Means of Response Feature Surrogates
PublicationFabrication tolerances and other types of uncertainties, e.g., the lack of precise knowledge of material parameters, have detrimental effects on electrical and field performance of antenna systems. In the case of input characteristics these are particularly noticeable for narrow- and multi-band antennas where deviations of geometry parameters from their nominal values lead to frequency shifts of the operating frequency bands. Improving...
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Dual-band antenna with improved gain for WLAN and ISM applications
PublicationIn this Letter, a dual-band antenna with an improved gain is proposed. The structure features 9.7 and 10.4 dBi gain within 2.4 GHz to 2.5 GHz and 5 GHz to 6 GHz bands, respectively. This makes it suitable for WLAN and ISM applications. The structure comprises an asymmetrical pair of radiators and slots suspended over a reflector. The antenna is optimised in a two-stage process using a trust-region-based gradient search algorithm....
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Expedited optimization of antenna input characteristics with adaptive Broyden updates
PublicationSimulation-driven adjustment of geometry and/or material parameters is a necessary step in the design of contemporary antenna structures. Due to their topological complexity, other means, such as supervised parameter sweeping, does not usually lead to satisfactory results. On the other hand, rigorous numerical optimization is computationally expensive due to a high cost of underlying full-wave electromagnetic (EM) analyses, otherwise...
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Expedited antenna optimization with numerical derivatives and gradient change tracking
PublicationDesign automation has been playing an increasing role in the development of novel antenna structures for various applications. One of its aspects is electromagnetic (EM)-driven design closure, typically applied upon establishing the antenna topology, and aiming at adjustment of geometry parameters to boost the performance figures as much as possible. Parametric optimization is often realized using local methods given usually reasonable...
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Frequency-Based Regularization for Improved Reliability Optimization of Antenna Structures
PublicationThe paper proposes a modified formulation of antenna parameter tuning problem. The main ingredient of the presented approach is a frequency-based regularization. It allows for smoothening the functional landscape of the assumed cost function, defined to encode the prescribed design specifications. The regularization is implemented as a special penalty term complementing the primary objective and enforcing the alignment of the antenna...
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Compact Dual-Polarized Corrugated Horn Antenna for Satellite Communications
PublicationIn this paper, a structure and design procedure of a novel compact dual-polarized corrugated horn antenna with high gain and a stable phase center for satellite communication is presented. The antenna incorporates an Ortho-Mode Transducer (OMT), a mode converter, and a corrugated structure. The compact OMT section is designed to be fed by standard WR-75 waveguides. The proposed compact design utilizes only ten corrugated slots...
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Asymmetrical-Slot Antenna with Enhanced Gain for Dual-Band Applications
PublicationDual-band operation is an important feature of antennas to be applied in modern communication systems. Although high gain of radiators is rarely of concern in urban areas with densely located broadcasting stations, it becomes crucial for systems operating in more remote environments. In this work, a dual-band antenna with enhanced bandwidth is proposed. The structure consists of a driven element in the form of an asymmetrical radiator/slot...
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ESPAR Antenna-Based WSN Node With DoA Estimation Capability
PublicationIn this paper, we present a low-cost energy-efficient electronically steerable parasitic array radiator (ESPAR) antenna-based wireless sensor network (WSN) node designed for IEEE 802.15.4 standard that is capable of performing direction of arrival (DoA) estimation in real-life outdoor environments. To this end, we propose the WSN node architecture, design and realization that utilizes NXP JN5168 radio frequency (RF) wireless transceiver...
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Performance-Based Nested Surrogate Modeling of Antenna Input Characteristics
PublicationUtilization of electromagnetic (EM) simulation tools is mandatory in the design of contemporary antenna structures. At the same time, conducting designs procedures that require multiple evaluations of the antenna at hand, such as parametric optimization or yield-driven design, is hindered by a high cost of accurate EM analysis. To certain extent, this issue can be addressed by utilization of fast replacement models (also referred...
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A Review of Antennas for Indoor Positioning Systems
PublicationThis paper provides a review of antennas applied for indoor positioning or localization systems. The desired requirements of thoseantennas when integrated in anchor nodes (reference nodes) are discussed, according to different localization techniques and theirperformance. The described antennas will be subdivided into the following sections according to the nature of measurements:received signal strength (RSS), time of flight (ToF),...
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UWB Microstrip Antennas on a Cylindrical Surfaces
PublicationConformal antennas are becoming popular due to their many advantages and possibilities of applications they offer. The advantages of using antennas with a curved surface arise not only from the possibility of integrating them with the object on which they are mounted on but also from the increase, relatively to planar antennas, of their visible angular range. The circular antenna arrays, or arrays of radiators located on the surface...
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Objective relaxation algorithm for reliable simulation-driven size reduction of antenna structure
PublicationThis letter investigates reliable size reduction of antennas through electromagnetic-driven optimization. It is demonstrated that conventional formulation of the design task by direct footprint miniaturization with imposing constraints on electrical performance parameters may not lead to optimum results. The reason is that—in a typical antenna structure—only a few geometry parameters explicitly determine the antenna footprint,...
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Rapid antenna design optimization using shape-preserving response prediction
PublicationAn approach to rapid optimization of antennas using the shape-preserving response-prediction (SPRP) technique and coarsediscretization electromagnetic (EM) simulations (as a low-fidelity model) is presented. SPRP allows us to estimate the response of the high-fidelity EM antenna model, e.g., its reflection coefficient versus frequency, using the properly selected set of so-called characteristic points of the low-fidelity model...
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Receiver block of antenna amplifier for WLAN systems in 5 GHz band
PublicationDwukierunkowe wzmacniacze antenowe (BDA) są często stosowane do zwiększania zasięgu łączności w sieciach bezprzewodowych WLAN. W artykule przedstawiono teorię, procedurę projektową oraz realizację części odbiorczej dwukierunkowego wzmacniacza do systemów WLAN na pasma 5GHz w standardach 802.11a i HiperLAN-2. Analizowano tylko te bloki, które wpływają na parametry toru odbiorczego. Aby ograniczyć koszt wzmacniacza wszystkie obwody...
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A Study on Dual-band Microstrip Rectangular Patch Antenna for Wi-Fi
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Enhancing Performance of Switched Parasitic Antenna for Localization in Wireless Sensor Networks
PublicationThis paper presents an Electronically Steerable Parasitic Array Radiator (ESPAR) antenna with enhanced performance of estimating the incoming signal direction. Designed antenna is dedicated for 2.4 GHz ISM applications with emphasis on Wireless Sensor Networks (WSN). The limitations of the existing design approach are illustrated, as well as perspectives and challenges of the proposed solution in relation to the localization in...
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A structure and simulation-driven design of compact CPW-fed UWB antenna
PublicationIn this letter, a structure of a miniaturized ultra-wideband CPW-fed antenna and its design proce-dure are presented. The antenna is a modified version of the design previously proposed in the literature, with additional degrees of freedom introduced in order to improve the structure flexibility. The small size is achieved by executing a rigorous optimization procedure that consists of two stages: (i) smart random search carried...
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Rapid EM-driven antenna dimension scaling through inverse modeling
PublicationIn this letter, a computationally feasible technique for dimension scaling of antenna structures is introduced. The proposed methodology is based on inverse surrogate modeling where the geometry parameters of the antenna structure of interest are explicitly related to the operating frequency. The surrogate model is identified based on a few antenna designs optimized for selected reference frequencies. For the sake of computational...
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On Reduced-Cost Design-Oriented Constrained Surrogate Modeling of Antenna Structures
PublicationDesign of contemporary antenna structures heavily relies on full-wave electromagnetic (EM) simulation models. Such models are essential to ensure reliability of evaluating antenna characteristics, yet, they are computationally expensive and therefore unsuitable for handling tasks that require multiple analyses, e.g., parametric optimization. The cost issue can be alleviated by using fast surrogate models. Conventional data-driven...
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Miniaturized uniplanar triple-band slot dipole antenna with folded radiator
PublicationA miniaturized uniplanar slot dipole for triple-frequency operation is presented. The antenna consists of a folded slot radiator with an increased number of degrees of freedom that allow for efficient size reduction. Rigorous electromagnetic (EM)-driven design optimization is applied in order to achieve the smallest possible size while maintaining acceptable levels of antenna reflection at the required operating frequencies. The...
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Three-objective antenna optimization by means of kriging surrogates and domain segmentation
PublicationIn this paper, an optimization framework for multi-objective design of antenna structures is discussed which exploits data-driven surrogates, a multi-objective evolutionary algorithm, response correction techniques for design refinement, as well as generalized domain segmentation. The last mechanism is introduced to constrain the design space region subjected to sampling, which permits reduction of the number of training data samples...
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Topological modifications for performance improvement and size reduction of wideband antenna structures
PublicationCompact antennas belong to the key components of modern communication systems. Their miniaturization is often achieved by introducing appropriate topological changes such as simple ground plane slots or tapered feeds. More sophisticated modifications are rarely considered in the literature because they normally lead to significant increase of the number of tunable parameters, which makes the antenna design process more challenging....
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Modelling of mutual coupling in microstrip antenna arrays fed by microstrip line.
PublicationPrzedstawiono wyniki modelowania sprzężenia pomiędzy prostokątnymi radiatorami mikropaskowymi w szyku liniowym anten zasilanych przez linie mikropaskowe. Zaproponowano schemat zastępczy sprzężenia w postaci kombinacji linii transmisyjnych wraz z sękami zwartymi i rozwartymi. Pokazano, że schemat taki dobrze modeluje sprzężenie w wąskim pasmie częstotliwości ok. 4%. Wyniki modelowania sprawdzono eksperymentalnie poprzez pomiary...
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Expedited design of microstrip antenna subarrays using surrogate-based optimization
PublicationComputationally efficient simulation-driven design of microstrip antenna subarrays is presented. The proposed design approach aims at simultaneous adjustment of all relevant geometry parameters of the subarray, which allows us to take into account the effect of the feeding network on the subarray radiation pattern (in particular, the side lobe level, SLL). In order to handle a large number of variables involved in the design process,...
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Design of microstrip antenna subarrays: a simulation-driven surrogate-based approach
PublicationA methodology for computationally efficient simulation-driven design of microstrip antenna subarrays is presented. Our approach takes into account the effect of the feed (here, a corporate network) on the subarray side-lobe level and allows adjustment of both radiation and reflection responses of the structure under design within a single automated process. This process is realized as surrogate-based optimization that produces...
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Novel Structure and EM-Driven Design of Small UWB Monopole Antenna
PublicationA novel structure of a small UWB monopole antenna is presented. In our approach, a compact size is achieved by means of a meander line for current path enlargement as well as the two parameterized slits that introduce additional degrees of freedom helping to ensure good impedance matching. The antenna design is carried out using surrogate-based optimization involving variable-fidelity EM simulations. This allows us to simultaneously...
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Two-Row ESPAR Antenna with Simple Elevation and Azimuth Beam Switching
PublicationIn this letter, we propose a two-row electronically steerable parasitic array radiator (ESPAR) antenna designed for direction of arrival (DoA) estimation in Internet of Things (IoT) applications relying on simple microcontrollers. The antenna is capable of elevation and azimuth beam switching using a simple microcontroller-oriented steering circuit and provides 18 directional radiation patterns, which can be grouped in 3 distinctive...
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Generalized Formulation of Response Features for Reliable Optimization of Antenna Input Characteristics
PublicationElectromagnetic (EM)-driven parameter adjustment has become imperative in the design of modern antennas. It is necessary because the initial designs rendered through topology evolution, parameter sweeping, or theoretical models, are often of poor quality and need to be improved to satisfy stringent performance requirements. Given multiple objectives, constraints, and a typically large number of geometry parameters, the design closure...
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On EM-driven size reduction of antenna structures with explicit constraint handling
PublicationSimulation-driven miniaturization of antenna components is a challenging task mainly due to the presence of expensive constraints, evaluation of which involves full-wave electromagnetic (EM) analysis. The recommended approach is implicit constraint handling using penalty functions, which, however, requires a meticulous selection of penalty coefficients, instrumental in ensuring optimization process reliability. This paper proposes...
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Multi-Taper-Based Automatic Correction of Non-Anechoic Antenna Measurements
PublicationPrototype measurements belong to the key steps in the development of antenna structures. Although accurate validation of their far-field performance can be realized in dedicated facilities, such as anechoic chambers, the high cost of their construction and maintenance might not be justified if the main goal of measurements is to support teaching or low-budget research. Instead, they can be performed in non-anechoic conditions and...
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Substrate Integrated Waveguide-Based Frequency-Tunable Self-Octaplexing Antenna
PublicationThis communication presents the first-ever substrate integrated waveguide (SIW)-based frequency-tunable self-octaplexing antenna (SOA) for wireless communication. The structure is arranged by implementing eight distinct patches with planar 50-ohm feedlines at the top of the SIW cavity, which realize eight distinct resonant frequencies. Independent tuning of each resonant frequency is achieved by incorporating appropriately allocated...
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A Multi-Antenna Scheme for Early Detection and Mitigation of Intermediate GNSS Spoofing
PublicationThis article presents a method for detecting and mitigating intermediate GNSS spoofing. In this type of attack, at its early stage, a spoofer transmits counterfeit signals which have slight time offsets compared to true signals arriving from satellites. The anti-spoofing method proposed in this article fuses antenna array processing techniques with a multipath detection algorithm. The latter is necessary to separate highly correlated...
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Ultra-Compact SIRC-Based Self-Triplexing Antenna with High Isolation
PublicationAn ultra-compact self-triplexing antenna realized on a substrate-integrated rectangular cavity (SIRC) is discussed in this study. The proposed structure employs two L-shaped slots and an in-verted U-shaped slot to radiate at three independent operating frequency bands. Three 50-ohm microstrip feed lines are used to excite the radiation in these slots. The operating frequency is individually tuned using the slot size. The slot placement...
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Calibration-Free Single-Anchor Indoor Localization Using an ESPAR Antenna
PublicationIn this paper, we present a novel, low-cost approach to indoor localization that is capable of performing localization processes in real indoor environments and does not require calibration or recalibration procedures. To this end, we propose a single-anchor architecture and design based on an electronically steerable parasitic array radiator (ESPAR) antenna and Nordic Semiconductor nRF52840 utilizing Bluetooth Low Energy (BLE)...
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Robust Parameter Tuning of Antenna Structures by Means of Design Specification Adaptation
PublicationParameter tuning through numerical optimization has become instrumental in the design of high-performance antenna systems. Yet, practical optimization faces several major challenges, including high cost of massive evaluations of antenna characteristics, normally involving full-wave electromagnetic (EM) analysis, large numbers of adjustable variables, the shortage of reasonable initial solutions in the case of topologically complex...
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Influence of User Mobility and Antenna Placement on System Loss in B2B Networks
PublicationIn this paper, the influence of user mobility and on-body antenna placement on system loss in body-to-body communications in indoor and outdoor environments and different mobility scenarios is studied, based on system loss measurements at 2.45 GHz. The novelty of this work lies on the proposal of a classification model to characterise the effect of user mobility and path visibility on system loss, allowing to identify the best...
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A Conformal Circularly Polarized Series-Fed Microstrip Antenna Array Design
PublicationA conformal circularly polarized series-fed microstrip array design for broadside radiation is presented. The array aperture under design is conformal to a cylindrical surface of a given radius. The approach we present primarily addresses focusing of the circularly polarized major lobe of the conformal array by proper dimensioning of the aperture spacings. The proposed analytical models yield the values of the element spacings...
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Enhanced-Performance Circularly Polarized MIMO Antenna with Polarization/Pattern Diversity
PublicationDesign of a compact wideband circularly polarized (CP) multiple-input multiple-output (MIMO) antenna with polarization diversity is proposed and characterized for off-body communication. The antenna is based on a simple coplanar waveguide (CPW)-fed monopole extension of the microstrip line. The orthogonal field components required by CP are induced using a simply modified right/left side ground plane. In particular, a stub extending...
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Low-Profile Interdigitated UHF RFID Tag Antenna for Metallic Objects
PublicationThis article presents a novel miniature interdigitated ultra-high frequency (UHF) radio frequency identification (RFID) tag antenna that can be placed on metallic objects. The tag structure comprises two horizontal strip lines, each loaded with seven identical open stubs, and an integrated circuit (IC) chip connected directly to the feed lines in the middle of the structure. The perfect match to the IC chip’s impedance is realized...
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Reduced-Cost Constrained Modeling of Microwave and Antenna Components: Recent Advances
PublicationElectromagnetic (EM) simulation models are ubiquitous in the design of microwave and antenna components. EM analysis is reliable but CPU intensive. In particular, multiple simulations entailed by parametric optimization or uncertainty quantification may considerably slow down the design processes. In order to address this problem, it is possible to employ fast metamodels. Here, the popular solution approaches are approximation...
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Influence of Dielectric Overlay Permittivity on Size and Performance of Miniaturized ESPAR Antenna
PublicationIn this paper, influence of dielectric overlay permittivity on miniaturized ESPAR antenna parameters is presented. ESPAR antenna is a low-cost and energy-efficient way to implement beam steering capability to a node and improve network performance. The antenna size reduction is obtained by embedding its active and passive elements in ABS based materials of relative permittivity equal to 4, 5.5 and 7.5 in order to achieve network...
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Improved jamming resistance using electronically steerable parasitic antenna radiator
PublicationThis paper presents an idea of using an Electronically Steerable Parasitic Antenna Radiator (ESPAR) for jamming suppression in IEEE 802.11b networks. Jamming (intentional interference) attacks are known to be effective and easy to perform, which may impose connectivity problems in applications concerning Internet of Things (IoT). In our paper, theoretical considerations are presented and the results of experiments performed in...