Broadband Antenna Design Research Articles

Antenna Design for Absolute Sky Measurements at Gigahertz Frequencies—a First Step toward Detecting CMB Spectral Distortions from Recombination

There exist inevitable deviations in the cosmic microwave background spectrum from that of a blackbody. The additive distortions from photons emitted over the epoch of recombination are one such deviation. We present a novel scalable broadband antenna design motivated by detecting these spectral distortions in the 2.5–4 GHz band. This antenna is capable of maintaining the spectral quality of the measured sky spectrum to 1 part in 103 over the full band and outperforms conventional broadband antennas by at least an order of magnitude. While this is not sufficient to make a direct detection of the cosmological recombination radiation, it meets the baseline design criteria for an experiment that can make an absolute measurement of the sky spectrum at the millikelvin level, thereby making it capable of improving foreground models to global signal detection experiments (including those from cosmic dawn and the epoch of reionization) and addressing the problem of the excess radio background at 3.3 GHz reported by the ARCADE2 experiment.

Shared-radiator design of broadband and dual-mode antenna for personal role radio applications

Abstract Shared-radiator design of a broadband and dual-mode antenna that simultaneously covers the VHF/UHF band and satellite navigation band is presented for personal role radio (PRR) applications. Quadrifilar helix antenna (QHA) is devised to be a circularly polarized radiator which as well acts as a part of the upper half radiation arm of the dipole antenna and be equivalent to a linearly polarized radiation current carrier at VHF/UHF band, forming a symmetrical dipole antenna with a sinusoidal current distribution. A 5th-order balanced matching network comprised of five cascade L-sections is adopted to obtain the maximum possible working band-width and a 3.76:1 band-width (116 %) at VHF/UHF band is achieved. Strong mutual coupling effect of the two operating modes is observed near 1.5 GHz originated from QHA shared-radiator design, and a new balun structure is applied to achieve high isolation and self-decoupling, subsequently |S21| of the two operating modes is significantly reduced from about −18 dB to below −32 dB at satellite navigation band without affecting the reflection coefficient and radiation efficiency. The measured results show that radiation patterns of the manufactured prototype is basically consistent with corresponding simulation counterparts.

THz Microstrip Antenna for Terabit Wireless Local Area Networks

In order to replace millimetre wave communication for extremely fast terabit wireless local and personal area network connectivity, researchers have been looking into the possibilities of the terahertz band for establishing wireless data communication at terabit rates. The IEEE 802.15 WPAN Terahertz Interest Group (IGTHz) has been created to encourage research in the terahertz bands and set standards for their use, in order to facilitate progress and advancement in this area. The specific objective of this study is to design and analyze a microstrip antenna working at 3.5 THz resonant frequency. The proposed novel antenna includes three layers: a top layer that represents the patch, a second layer that represents the substrate, and a bottom layer that represents the ground plane. It is designed using a 32 nm thin FR-4 substrate with a permittivity of 4.4. Using HFSS simulations, it was found that the proposed antenna has an overall efficiency greater than 85% within the working frequency range of 3.5 THz. Additionally, it exhibited an extremely low reflection coefficient (S11) of -43.61 dB at 3.5 THz, with an efficiency exceeding 80%. This simple and broadband antenna design could have relevance in high-speed data transmission networks.

NUMERICAL MODELLING OF ELECTROMAGNETIC WAVE SCATTERING ON GRATINGS WITH ONE-DIMENSIONAL QUASI-FRACTAL PERIOD STRUCTURE

Numerical modelling of the properties of E-polarised and H-polarised waves scattered on periodic screened quasi-fractal gratings is carried out. The location of the band system at each period is determined by the principle of constructing a generalized symmetric Cantor set at a certain step of the algorithm. A mathematical model of the problems based on systems of boundary singular integral equations of the first kind was used in the study. These systems of equations were obtained using the method of parametric representations of singular and hypersingular integral operators. The systems of singular integral equations were solved numerically using the computational schemes of the method of discrete singularities. The solutions of these equations are used to obtain the main characteristics of the electric and magnetic fields. This experiment proved the possibility of using the MDS computational scheme to analyse systems containing 8 – 16 bands at different distances from each other. Graphs of the dependence of harmonic amplitudes on the wavenumber, point plots of absolute values of all non-zero harmonics at resonant wavenumber values, and maps of electric and magnetic field components in the region above the grating were obtained. It is confirmed that the overall field structure in the case of normal incidence is significantly influenced by all harmonics with absolute numbers from 0 to 50. The harmonics had a large number of resonances that were observed at different values of the wavenumber. This led to a complex structure of the isolines of absolute values of the scattered electric and magnetic field amplitudes in the region above the structure, and a significant difference in amplitude values with small changes in coordinates. In the future, it is planned to carry out computer simulations for imperfectly conducting structures and compare the results with the numerical results for the ideal case considered in this paper. The proposed structure may be of interest for the design of multimode broadband antennas.

Design of Compact Wide-beam Broadband Antenna for Wide-angle Scanning Applications

Design of Compact Wide-beam Broadband Antenna for Wide-angle Scanning Applications

An Impedance Relation and Its Application in Broadband Antenna Design

A triangular monopole antenna and a bitriangular slot antenna are designed and measured, respectively, in order to validate a relation between the input impedances of such noncomplementary antennas. The first application of the newly validated impedance relation is demonstrated with the creation of nonself-complementary antennas, which consist of the triangular monopole and the bitriangular slot. As expected, the nonself-complementary antennas indeed exhibit broad impedance bandwidths and stable radiation patterns. Furthermore, the novel nonself-complementary antennas have the advantages of simpler structures and feed than those of the existing nonself-complementary antennas. Hence, they can be easily and inexpensively manufactured.

Design and Characterization of Compact Broadband Antenna and Its MIMO Configuration for 28 GHz 5G Applications

This paper presents the design and characterization of a compact broadband antenna and its MIMO configuration for 28 GHz 5G applications. The antenna was designed using Rogers RT/5880 with a thickness of 1.575 mm and has an overall compact size of 30 mm × 30 mm. The design methodology was initiated by designing a compact conventional microstrip antenna for 28 GHz. Afterward, the rectangular slots were utilized to improve the impedance bandwidth so that antenna covers the globally allocated 28 GHz band spectrum for 5G applications. Furthermore, a compact 2 × 2 MIMO antenna with polarization diversity is designed for high channel capacity systems. The mutual coupling between the closely spaced antenna elements is reduced by using two consecutive iterations of defected ground structure (DGS). The proposed MIMO antenna system offers broad bandwidth, high gain, low mutual coupling, and low envelope correlation coefficient along with high diversity gain, low mean effective gain, and low channel capacity loss. Moreover, the proposed been compared with the state-of-the-art MIMO antenna proposed for 28 GHz application to demonstrate worth of the presented design.

A novel compact broadband and radiation efficient antenna design for medical IoT healthcare system.

This paper investigates and develops a novel compact broadband and radiation efficient antenna design for the medical internet of things (M-IoT) healthcare system. The proposed antenna comprises of an umbrella-shaped metallic ground plane (UsMGP) and an improved radiator. A hybrid approach is employed to obtain the optimal results of antenna. The proposed solution is primarily based on the utilization of etching slots and a loaded stub on the ground plane and rectangular patch. The antenna consists of a simple rectangular patch, a 50 Ƹ microstrip feed line, and a portion of the ground plane printed on a relatively inexpensive flame retardant material (FR4) thick substrate with an overall compact dimension of 22 × 28 × 1.5 mm3. The proposed antenna offers compact, broadband and radiation efficient features. The antenna is carefully designed by employing the approximate calculation formulae extracted from the transmission line model. Besides, the parameters study of important variables involved in the antenna design and its influence on impedance matching performance are analyzed. The antenna shows high performance, including impedance bandwidth of 7.76 GHz with a range of 3.65Ƀ11.41 GHz results in 103% wider relative bandwidth at 10 dB return loss, 82% optimal radiation efficiency in the operating band, reasonable gain performance, stable monopole-shaped radiation patterns and strong current distribution across the antenna lattice. The suggested antenna is manufactured, and simulation experiments evaluate its performance. The findings indicate that the antenna is well suited for medical IoT healthcare systems applications.

A Novel Broadband Antenna Design for 5G Applications

Wireless communication is one of the rapidly-growing fields of the communication industry. This continuous growth motivates the antenna community to design new radiating structures to meet the needs of the market. The 5G wireless communication has received a lot of attention from both academia and industry and significant efforts have been made to improve different aspects, such as data rate, latency, mobility, reliability and QoS. Antenna design has received renewed attention in the last decade due to its potential applications in 5G, IoT, mmWave, and massive MIMO. This paper proposes a novel design of broadband antenna for 5G mmWave and optical communication networks. It is a hybrid structure that works for both spectrums and contains an absorption dielectric material with an electrical large size. A hybrid transmission line theory ray-tracing technique is proposed efficient and rapid simulation and optimization of the proposed antenna design. The operating frequency and wavelength of the proposed antenna are 28 GHz in the mmWave band and 1550 nm for the optical spectrum. The spatial frequency is 30 lp/mm when the contrast transfer function is reduced to 0.7 for the optical signal. The effective focal length and aperture are 816.86 and 200 mm. The half-power beamwidth is 3.29° and the gain is 32.97 dBi for the mmWave band. Simulation results show that the proposed hybrid antenna can effectively be deployed simultaneously for both optical and mmWave 5G communication networks.

Dynamic frequency analysis of stress–strain-dependent reversibly deformable broadband RF antenna over unevenly made elastomeric substrate

This paper presents the design and development of stretchable and deformable broadband antenna using low-cost silicone rubber-based dielectric substrate. A slot is introduced in the substrate to improve the stretchable behaviour. The dielectric properties of the substrate are measured using suspended ring resonator method. The proposed antenna uses silver elastomeric Lycra fabric as the conductive medium. The resistivity of the conducting Ag fabric is 1 $$\Omega $$ per sq. mm. The conducting patch and ground plane are attached with the substrate using silicone-based adhesive. The fabricated antenna is tested for its resonant characteristics using the vector network analyser.

Design and Simulation of Broad Band Antenna for Rf Energy Harversting

The harvesting of radio frequency energy is a growing priority for providing power to electronic devices. With the aid of Inverted F antenna, this project proposes to create an energy harvesting system using RF radiation. Using the survey, we recognized that energy harvesting with RF is more effective than the other natural resources. Therefore we can further harvest enough energy that can be used for micro devices. Inverted F antenna has higher gain, simpler to feed and smaller size compared to spiral antenna, directional antenna etc. For the antenna design and simulation HFSS tool is used.

Broadband Antenna Design With Integrated CB-CPW and Parasitic Patch Structure for WLAN, RFID, Wimax, and 5G Applications

This paper presents a novel CB-CPW wideband antenna design. HFSS software simulations reveal that the proposed design has a semicircle ground structure, transmission line, parasitic ground, CPW, relatively low return loss, broadband effect of 3.3377 GHz (4.8337 GHz-8.1714 GHz), double beam capability at 5.2 GHz, and four-beam capability at 5.5 GHz (5.8 GHz). It is compact in size at only 40 mm × 40 mm × 1 mm. A prototype of the proposed antenna was fabricated and measured to validate the simulated design; the results show a bandwidth of 3.38 GHz (3.95 GHz-7.33 GHz), relative bandwidth of 74%, and maximum gain of 3.87 dBi in the range of 5 GHz to 6 GHz; the prototype also achieves two and four-beam performance. Its working frequency covers WLAN (5.15 GHz-5.25 GHz and 5.725 GHz-5.825 GHz), radio frequency identification RFID (5.8 GHz), and global microwave internet access WiMAX (5.25 GHz-5.85 GHz) frequency bands.

Comparative Study of Optimization Algorithms on the Design of Broadband Antennas

Broadband antennas find many applications in modern communication systems, such as Wi-Fi, 5G, and SatCom. Multiple competing optimization methods are available for the application to antenna design, while it would be preferable to know in advance if any method is superior. Here, an application of the cross-entropy method, along with particle swarm optimization and covariance matrix adaptation evolutionary strategy, to the design of broadband antennas is presented. The first example is an aperture-coupled microstrip patch antenna that has 9.5 dBi peak directivity and 53% bandwidth after optimization. It is then used as a feed in a high-gain broadband resonant cavity antenna. Using an all-dielectric superstrate with a transverse permittivity gradient, a compact thin resonant cavity antenna with a peak directivity of 19 dBi and 40% 3-dB bandwidth was designed. A comparative analysis of the cross-entropy method, particle swarm optimization, and covariance matrix adaptation evolutionary strategy applied to these two problems was carried out to provide the basis for further optimization of antennas in radio frequency and microwave frequency bands. We found that although all three methods reached a similar solution, the cross-entropy method has a speed advantage. It improves our ability to optimize existing designs and has wider applicability beyond antenna engineering.

The Design and Fundamentals of Printed Antennas [Book/Software Reviews

This book focuses more on practical antenna design than theoretical analysis and presents a good balance between fundamentals and the printed antenna design. This text concentrates on real-world antenna design and avoids too many formulations and theories. Includes topics that cover fundamentals of printed and microstrip antennas. These principles are presented in a logical way, beginning with an examination of single-element printed antennas and moving on to a system- level review of printed antenna fundamentals, antenna design techniques, and real-world, application-based antenna designs. The book also features information on an overview of antenna design used in smartphones; various compliance requirements of mobile phone antenna designs; frequency and polarization reconfiguration; printed ray antennas, microwave remote sensing; phased array antennas; automobile antenna design, and recent research and development trends in the design, analysis, and synthesis of broadband, multiband, and reconfigurable antenna for modern wireless systems. Taken together, the chapters provide several antenna design projects to demonstrate antenna design steps, antenna physical dimensions, and simulation results. This book begins with a very basic introduction of ultrawideband (UWB) antenna theory and a simple explanation of each type of UWB antenna. This is a perfect starting point for entry-level UWB antenna designers, equipment designers, and operators.

Design of a broad‐band microstrip loop antennas with less‐dispersive group velocity for accurate direction finding

This study proposes the design of broad-band microstrip loop antennas with less-dispersive group velocity of radiation patterns for accurate direction of arrival (DoA) estimation. The proposed structure consists of radiating and feeding microstrip loops, and the radiating loop is electromagnetically coupled to the feeding loop. This feeding mechanism helps to suppress phase variations of radiating patterns by avoiding dual resonances within a wide frequency band over 60 MHz, which allows to obtain the less-dispersive group velocity for accurate DoA estimation. The effectiveness of the less-dispersive behaviour is validated by implementing the proposed structure into a four-element array to estimate vertical and horizontal placements using dual-axis phase interferometry. The results confirm that the proposed antenna has less-dispersive group velocity compared to a conventional microstrip patch antenna and is more suitable for accurate DoA estimation.

Dual Circular Polarization with Reduced Mutual Coupling Among Two Orthogonally Placed CPW-Fed Microstrip Antennas for Broadband Applications

In this communication, a design of Coplanar Waveguide-fed Dual Circularly Polarized Broadband Antenna (CPW-DCPBA) has been proposed. Here, a square slot consists of two orthogonal T-shaped asymmetric microstrip antennas protruded from a signal line of CPW feed has been presented. The microstrip antennas are isolated with an inverted-L type grounded strip embedded at the left corner, followed by a square strip. A modified meandered line (MML) is embedded with the square strip to achieve circular polarization at the lower frequency. An SRR is placed at the back of the antenna to enhance the 3-dB axial ratio bandwidth (ARBW). Measurements of the fabricated antenna show an impedance bandwidth of 88% and the 3-dB ARBW of 75%, in which return loss is better than 10 dB and the isolation among the antennas are better than 15 dB. A peak gain of 3.1–5.6 dBi is achieved within the axial ratio band. The antenna is fabricated on FR-4 substrate of 60 mm × 60 mm × 1.6 mm with an antenna area of 0.359λ 0 2 . The simulated results are in good agreement with the measured results which verified its usage for broadband applications.

Experimental demonstration of conformal phased array antenna via transformation optics

Transformation Optics has been proven a versatile technique for designing novel electromagnetic devices and it has much wider applicability in many subject areas related to general wave equations. Among them, quasi-conformal transformation optics (QCTO) can be applied to minimize anisotropy of transformed media and has opened up the possibility to the design of broadband antennas with arbitrary geometries. In this work, a wide-angle scanning conformal phased array based on all-dielectric QCTO lens is designed and experimentally demonstrated. Excited by the same current distribution as such in a conventional planar array, the conformal system in presence of QCTO lens can preserve the same radiation characteristics of a planar array with wide-angle beam-scanning and low side lobe level (SLL). Laplace’s equation subject to Dirichlet-Neumann boundary conditions is adopted to construct the mapping between the virtual and physical spaces. The isotropic lens with graded refractive index is realized by all-dielectric holey structure after an effective parameter approximation. The measurements of the fabricated system agree well with the simulated results, which demonstrate its excellent wide-angle beam scanning performance. Such demonstration paves the way to a robust but efficient array synthesis, as well as multi-beam and beam forming realization of conformal arrays via transformation optics.

Full characterisation of a background limited antenna coupled KID over an octave of bandwidth for THz radiation

We present the design, fabrication, and full characterisation (sensitivity, beam pattern, and frequency response) of a background limited broadband antenna coupled kinetic inductance detector covering the frequency range from 1.4 to 2.8 THz. This device shows photon noise limited performance with a noise equivalent power of 2.5 × 10−19 W/Hz1∕2 at 1.55 THz and can be easily scaled to a kilo-pixel array. The measured optical efficiency, beam pattern, and antenna frequency response match very well the simulations.

MULTILAYERED BROADBAND ANTENNA FOR COMPACT EMBEDDED IMPLANTABLE MEDICAL DEVICES: DESIGN AND CHARACTERIZATION

Design and characterization of a multilayered compact implantable broadband antenna for wireless biotelemetry applications is presented in this paper. The main features of this novel design are miniaturized size, structure that allows integration of electronic circuits of the implantable medical device inside the antenna, and enhanced bandwidth that mitigates possible frequency detuning caused by heterogeneity of biological tissues. Using electromagnetic simulations based on the finite-difference timedomain method, the antenna geometry was optimized to operate in the 401-406 MHz Medical Device Radio communications service band. The proposed design was simulated implanted in a muscle tissue cuboid phantom and implanted in the arm, head, and chest of a high-resolution whole-body anatomical numerical model of an adult human male. The antenna was fabricated using low-temperature co-fired ceramic technology. Measurements validated simulation results for the antenna implanted in muscle tissue cuboid phantom. The proposed compact antenna, with dimensions of 14mm × 16mm × 2 mm, presented a -10 dB bandwidth of 103 MHz and 92MHz for simulations and measurements, respectively. The proposed antenna allows integration of electronic circuit up to 10mm × 10mm × 0.5 mm. Specific absorption rate distributions, antenna input power, radiation pattern and the transmission channel between the proposed antenna and a half-wavelength dipole were evaluated.

A Novel Broadband Antenna Design for UHF RFID Tags on Metallic Surface Environments

In this letter, a novel ultrahigh-frequency radio frequency identification (UHF RFID) tag antenna is proposed. Suitable for metallic objects, this broadband antenna can cover the three major UHF RFID bands. A modified folded dipole and a meander bar have been implemented on the upper substrate, while the second substrate is a double face with parallel bars printed on the top face and a metal plane on the bottom to isolate the antenna from metallic surfaces. The bars are used as parasitic elements to excite multiresonant modes and enhance the antenna bandwidth. To improve the gain of the antenna, the two substrates have been speared by an air layer. Furthermore, the proposed design is cost-effective since it does not require metallic vias. Mounted on a metallic plate of 300 × 250 mm2, the proposed antenna covers the targeted UHF RFID bands with a return loss better than 10 dB and a maximum outdoor measured reading range of 14.6 m at 905 MHz.