Realization Of Antenna Research Articles

Silicon elastomer as flexible substrate: dielectric characterization and applications for wearable antenna

In this paper, low-cost mold silicone and silicone elastomers are investigated as substrates for the realization of flexible antennas. A methodical dielectric characterization is carried out, followed by a detailed explanation of the manufacturing process of the silicone elastomers. The prepared silicone elastomer substrates are also subjected to mechanical tests to ensure flexibility and robustness. The mechanical tests corroborated the utilization of the prepared silicone elastomers for the flexible antennas. Silicone has limited adhesion to metal, so when producing a silicone substrate, a 0.5 mm deep cavity is created with a negative impression of the intended metal component. Consequently, the metal layer is embedded within the silicon substrate, aligning the top surface of the metal flush with the silicone substrate edges. The radio frequency (RF) structure incorporates ridges within the silicone substrate to form a gap, effectively securing the metal on the surface of the silicone. Finally, to prevent the metal from falling from the silicone substrate, Kapton tape is laminated on the substrate. The wrapping of the Kapton tape additionally provides protection from moisture since the silicone elastomer substrate is prone to moisture absorption. The proposed technique is experimentally verified by designing and prototyping a coplanar patch antenna using copper and conductive woven fiber on the silicone substrate. The simulation analysis and experimentation results authenticated the effectiveness of the proposed technique to design a flexible antenna on the silicone elastomer substrates. It is also concluded that the conductive woven fiber-based prototype offers higher flexibility as compared to the copper-based prototype. It is also clinched that there exists a trade-off in flexibility and performance characteristics due to the conductivity and texture difference between the copper and conductive woven fiber.

Design and Realization of Wearable Textile Slotted Waveguide Antennas.

The design of wearable antennas presents a challenge from multiple perspectives, as they must meet technical requirements and satisfy safety standards while also being suitable for integration into clothing and aesthetically pleasing. In recent years, the development of conductive fabrics has, in many ways, allowed for significant progress in the manufacturing of wearable antennas, and in previous work, we developed textile slotted waveguide antennas using conductive textiles and traditional sewing processes. However, various aspects of the design and realization of such antennas remain challenging. In particular, this work investigates the issue of using foam-based molds, which enables the realization of thin, flexible, wearable antennas, as well as the issue of antenna feed, specifically the transition from a classic coaxial transmission line to a waveguide. The design of the transition was focused on simplicity and robustness, due to which we limited the number of degrees of freedom in the design process in order to achieve a structure suitable for mounting on textile waveguide antennas. In addition, the antenna design procedure and the body-channel model were considered in order to optimize the performance of the antennas and the wireless body-centric system itself. Several prototypes of different kinds were developed in the 5.8 GHz ISM band, confirming the feasibility of the proposed concepts through experimental results.

Design and Realization of Metamaterial Antenna for Enhancement of Antenna Parameters in 5G Frequency

Technological advancements, particularly in telecommunications, are accelerating. The speed of which data is sent and received is a critical demand in the rapidly expanding telecommunications sector. Fifth - generation (5G) technology necessitates the use of antenna that can effectively send and receive data. This study examines the design and realization of a microstrip antenna that operates at 3.5 GHz utilizing Electromagnetic Band Gap (EBG). The usage of an EBG can optimize antenna quality and dimensions. Based on the simulation results, the original antenna without EBG obtained S11 of -30.76 dB with a Gain of 2.653 dBi at 3.5 GHz. By adding the EBG structure with 4 x 4 configuration, the simulation results show a better S11 of -40.021dB and a higher Gain of 4.229 dBi, at a distance of 5 mm between the antenna and the EBG structure. For the measurement results, this antenna obtained S11 of -33.088 dB with a Gain of 4.3 dBi. In addition, there is a change in the radiation pattern between the Regular Antenna and the Antenna with EBG. In the antenna radiation pattern with EBG the current direction is reflected in phase and result in constructive reflection. Based on the parameters obtained from measurements and simulations, the antenna has achieved the target specification and can be used at a frequency of 3.5 GHz.

5G/Millimeter-Wave Rectenna Systems for Radio-Frequency Energy Harvesting/Wireless Power Transmission Applications: An overview

In this article, we present an overview of the 5G rectifying antenna and its primary elements for applications in millimeter-wave (mm-wave) energy harvesting (EH) and wireless power transmission (WPT). The wide spectrum available for 5G communication bands have attracted significant attention for extensive applications. The power received by the harvesting antenna relies on the size of the antenna. Hence, the realization of antenna and rectenna systems with good efficiency at 5G mm-wave is a challenge. This review article highlights the recent advances in 5G rectenna systems for different applications at the component and structure levels. The primary objectives of the article are 1) to explore the potential advances of mm-wave rectenna systems and the feasibility of their designs to attain desired characteristics and 2) to present a comparative assessment of performance parameters of existing rectenna systems.

Low cross polarized leaf shaped broadband antenna with metasurface as superstrate for sub 6 GHz 5 G Applications

This article presents the design, circuit model analysis, and realization of a metasurface-based novel leaf-shaped antenna for sub 6 GHz 5 G NR frequency bands like n77 (3.3–4.2 GHz), n78 (3.3–3.8 GHz), n79 (4.4–5 GHz), and n90 (2.4–2.6 GHz) applications. Primarily, a leaf-shaped microstrip planar antenna is designed and provides a broad impedance bandwidth of 77.43% (2.2–4.98 GHz), a peak gain of 4.51 dBi, and a high radiation efficiency of 94.16%. The planar antenna is integrated with a 5 × 3 elements periodic metasurface (MS) array to enhance radiation performance. Both the radiating leaf planar and the MS layer have been designed on a low-cost FR4 epoxy substrate, and equivalent circuit models have been developed for both successively to validate the EM simulated results. The overall dimensions of the planar antenna with MS layer are 0.45 λ0 × 0.27 λ0 × 0.108 λ0, (λ0 corresponds to lowest resonant frequency f=2.7 GHz). The tested antenna with MS superstrate covers a broad range of operating frequencies from 2.29 to 4.78 GHz (2.49 GHz) with a − 10 dB impedance fractional bandwidth of 70.43% and has an excellent reflection coefficient of more than − 35 dB for the entire operating band. The experimental peak gain and higher radiation efficiency are 8.76 dBi and 96.6%, respectively. Moreover, all these parameters are extremely high in single-layer planar antennas, including the stable omnidirectional radiation pattern with very low cross-polarization of − 53.34 dB.

Pin-on-Substrate Gap Waveguide: An Extremely Low-Cost Realization of High-Performance Gap Waveguide Components

Considering the limitations of currently available technologies for the realization of microwave components and antennas, a trade off between different factors including the efficiency and fabrication cost is required. The main objective of this letter is to propose a novel method for the realization of gap waveguides (GWGs) that take advantage of conventional printed circuit board fabrication technology, thus are low cost and light weight. Moreover, by avoiding dielectric loss and minimizing conductive loss, the proposed GWGs benefit from a very low loss. To highlight potential applications, a high-performance slot-array antenna based on the proposed GWG is presented.

Modified Slotted Patch Antenna With Metasurface as Superstrate for Dual-Band Applications

This letter presents the design, circuit model analysis, and realization of a novel metasurface-based low-profile slotted patch antenna for dual-band applications in the C and X-bands. The antenna prototype comprises a modified slotted patch and a 7×7 array of periodic metasurface (MS) as superstrate configuration. Both the radiating patch and the MS layer have been designed over FR4 dielectric substrate while the overall dimension of the proposed antenna being 1.03λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×1.03λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.15λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> only, where λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the free-space wavelength at 8.62 GHz. The −10 dB impedance bandwidth of the proposed antenna has been realized at two distinct frequency bands ranging from 4.18 to 4.44 GHz and 8.11 to 11.14 GHz. The fractional bandwidths of 6.1% and 35.15% have been achieved at 4.26 and 8.62 GHz, respectively. The equivalent circuit model of the proposed prototype has been sequentially developed to validate the electromagnetic simulated results. The antenna radiates in the boresight direction, with a maximum realized gain of 8.72 dBi at 10.99 GHz and radiation efficiency of 91%. The proposed prototype has also been fabricated and the experimentally measured results are in good resemblance with the simulated one.

A Filtering Antenna Using Transversal Coupling Topology

In this letter, a coupling scheme for the realization of filtering antennas is introduced. This coupling scheme allows the filtering antenna to realize a filter-like reflection coefficient using an all-radiator structure. Instead of cascading resonators one by one in a ladder manner, in a transversal filtering antenna (TFA), all the radiative resonators are coupled to the source simultaneously. The impedance and radiation behaviors of these subantennas (SAs) can be designed individually. So, the performance of these filtering antennas has much lower sensitivity to their physical structure than conventional cascaded designs, which makes the design of such a filtering antenna much easier. Besides, this topology can realize out-of-band gain zeros without using any parasitic elements or cross-coupling structures. The locations of these gain zeros can be controlled by simply changing the lengths of each SA. To the authors’ knowledge, this is the first time that a transversal filtering antenna with all resonators radiative is presented. For validation, some transversal filtering antenna designs with different coupling topologies are introduced to prove the concept and show their advantages. A third-order prototype is fabricated and measured for demonstration, showing good agreement between the simulated and measured results.

A new compact grounded coplanar waveguide slotted multiband planar antenna for radio frequency identification data applications

&lt;p&gt;&lt;span&gt;This research presents the development and conception of a new compact grounded coplanar waveguide fed slotted rectangular planar antenna with a multi-frequency band for &lt;a name="_Hlk94076774"&gt;&lt;/a&gt;radio frequency identification data (RFID) reader applications which is based on the antenna mono-band frequency to use for a various applications RFID to support a different operating range. The optimized of the final prototype designing operates a multiple frequency bands ranging from 0.7-1.1 GHz, 2.2-2.5 GHz and 5.4-6 GHz for 0.9/2.4 GHz and 5.8 GHz RFID operation bands which is adapted from ultra-high frequency band (0.9 GHz) to microwave frequency band (2.4-5.8 GHz) RFID systems. This antenna is implemented and printed on a FR4 substrate with a size of 30×50×1.6 mm&lt;sup&gt;3&lt;/sup&gt;. The novel prototype includes of a radiator rectangular patch with a symmetrical slot and a U-slot with I-stub on ground plan. The principles parameters of the antenna have been studied optimized and miniaturized by using a two simulators CST Microwave Studio and advanced design system (ADS) to validate the simulation results before the planar antenna realization. The final structure is achieved and validated of the results measurement. Experimental results show that the proposed antenna with a small size has good and stable radiation and thus promising for a various RFID applications.&lt;/span&gt;&lt;/p&gt;

Simple wideband extended aperture antenna-inspired circular patch for V-band communication systems

This article presents the design and realization of compact, geometrically simple, wideband and high gain antenna for V-band communication systems. The antenna is designed by using a conventional circular patch, which is further modified by using another fractal circular patch. Furthermore, the addition of three elliptical shaped patches significantly increases the bandwidth of the antenna. Afterwards, a circular slot is etched from the radiator to improve the radiation pattern of the antenna. The proposed structure comprises of an overall substrate size of 13 × 12 × 0.508 mm3 and designed using Duroid 5880 having very low loss tangent of 0.0009. To verify the presented results, the antenna prototype is fabricated and tested. The comparison among simulated and measured results shows a strong performance. Moreover, the comparison with state of the artwork shows that the antenna offers compact size, wide bandwidth, high gain, and good radiation efficiency. Thus, it makes the proposed antenna a potential candidate for the V-band communication systems.

Aluminum Cayley trees as scalable, broadband, multiresonant optical antennas

An optical antenna can convert a propagative optical radiation into a localized excitation and the reciprocal. Although optical antennas can be readily created using resonant nanoparticles (metallic or dielectric) as elementary building blocks, the realization of antennas sustaining multiple resonances over a broad range of frequencies remains a challenging task. Here, we use aluminum self-similar, fractal-like structures as broadband optical antennas. Using electron energy loss spectroscopy, we experimentally evidence that a single aluminum Cayley tree, a simple self-similar structure, sustains multiple plasmonic resonances. The spectral position of these resonances is scalable over a broad spectral range spanning two decades, from ultraviolet to midinfrared. Such multiresonant structures are highly desirable for applications ranging from nonlinear optics to light harvesting and photodetection, as well as surface-enhanced infrared absorption spectroscopy.

Laser-Induced Graphene, Fused Filament Fabrication, and Aerosol Jet Printing for Realizing Conductive Elements of UHF RFID Antennas

In this work, three promising Additive Manufacturing (AM)/3D-printing technologies, able to realize conductive elements, are adopted in the realization of antennas. The selected techniques are Fused Filament Fabrication (FFF), Aerosol Jet Printing (AJP), and Laser-Induced Graphene (LIG), which have been compared by measuring the performance of an ultrahigh (UHF) radiofrequency identification (RFID) tag, specifically designed, and realized for the scope. Results have also been analyzed against to data obtained by a reference sample realized in Aluminum. The FFF tag has been manufactured by extruding the Electrifi conductive filament over an ABS printed substrate, used also for the AJP-made antenna. Conversely, the LIG tag has been produced by laser-burning a Kapton polyimide sheet. All the tested technologies, each one with its pros and cons, allowed to realize working prototypes, even if, as expected, with performance lower than the comparison sample. An electroplating process has been also adopted to increase conductivity, with improvements in the FFF prototype. The obtained results are quite satisfactory. Those related to LIG technology do not yet guarantee performance comparable to the other techniques. Nevertheless, the prospect of creating “green” and cost-effective antennas pushes towards further studies, already underway, which include the study of antenna shapes more suitable for the specific technique as well as process optimizations to increase conductivity.

A shorting-pin based compact meander multiband printed monopole antenna

The antenna presented in this work is based on a meandering monopole patch antenna with the incorporated shorting-pin technique for the realization of multiband antenna. The proposed antenna is printed on an FR4 with a footprint of 0.22λg×0.36λg at the lowest operating frequency. The antenna proposed demonstrated six resonances with suitable bandwidth as well as gain which make it suitable for WiMAX, LTE-A, aeronautical radio navigation, sub6GHz band for 5G, and WLAN applications. The prototype of the proposed antenna is fabricated, measured, and presented. The comparative analysis of the proposed antenna with the recently reported works shows that the proposed antenna outperformed its counterpart in terms of size and number of bands. Therefore, the antenna reported in this work is a suitable and promising candidate for future portable mobile communication devices.

Microstrip leaky wave antenna for wide range of beam scanning in X band

AbstractIn this work, design of a pattern reconfigurable antenna is presented for X‐band applications as a leaky wave antenna (LWA) realization. Due to the advantages of simple design schematic, low profile, and easy impedance matching, LWA designs have been using as an efficient solution for reconfigurable antenna in many wireless communication applications. Optimization and simulation of the proposed LWA is carried out in 3‐D Microwave simulation CST environment and Honey Bee Mating is used as the optimization algorithm. Dimensions of the proposed LWA is 130 × 30 mm, which is fabricated on Rogers 5880 as capacitive loaded eight identical rectangular microstrip patches operating over 9.5‐12 GHz with a fractional bandwidth. The proposed LWA exhibits a measured peak gain of 11.8 dBi at 10 GHz with an overall gain characteristic of between 9.5 and 11.8 dBi over the range of 9.5 to 12 GHz with a steerable pattern characteristics between −45 and 50° as agreed with the theory. Furthermore, the fabricated LWA has been found to have the superior performance as compared with its counterparts.

SRR and Rectangular Stubs Loaded Novel Fractal Antenna Realization for Multiband Wireless Applications

This manuscript presents the novel design of Split Ring Resonator (SRR) and rectangular stubs loaded Circular Fractal Antenna for multiband wireless applications. Initially, the antenna is designed by introducing various fractal iterations from 0th to 3rd and the final iteration is designated as Antenna-I. This antenna exhibits the maximum bandwidth of 8.35 GHz from 4.12 to 12.47 GHz. Further, this bandwidth has been enhanced and inflated as 10.29 GHz from 2.07 to 12.36 GHz, by introducing the SRR structure in the geometry of 3rd iteration of the designed antenna and designated as Antenna-II. Similarly, to further improve the performance parameters the rectangular stubs are introduced in the structure of Antenna-II to obtain the proposed antenna final geometry called Antenna-III. The final structure of the proposed antenna shows improved impedance matching and exhibits the bandwidth of 11.43 GHz (1.30–12.73 GHz) and 5.17 GHz (14.83–20.0 GHz) in 1 to 20 GHz frequency range. The total dimensions of the proposed antenna is 36 × 32 mm2 and can be valuable for different multiband wireless applications such as a DCS, PCS, UMTS, Bluetooth, WiMAX, GSM, IEEE 802.16e, ITU, IEEE802.11a (WLAN)/b/g, C/S/X/Ku and K band.

Pengembangan Antena Bowtie 2,1 GHz Terintegrasi Artificial Magnetic Conductor (AMC) untuk Aplikasi Antena Transmitter pada Sistem Ground Penetrating Radar (GPR)

This study presented the development of the bowtie antenna system design as the transmitter in the Ground Penetrating Radar (GPR) system. The Artificial Magnetic Conductor (AMC) reflector was integrated into the antenna system as a ground plane to obtain a high gain, increase bandwidth and produce a low-profile antenna. The antenna is designed to work at a center frequency of 2.1 GHz with a range of 1.6 - 2.6 GHz and has ultrawideband (UWB) characteristics with a fractional bandwidth of ≥ 25%. In addition, the value of late-time ringing must also be reduced to -30 dB to prevent masking effects on the detected object. Antenna modeling and simulation was done to obtain the optimum prototype design. Bowtie antenna realization was carried out using RT Duroid 5880 as a substrate with dielectric constant (εr) = 2.2 and thickness (h) = 1.57 mm. The AMC reflector was fabricated with FR-4 Epoxy substrate with a dielectric constant (εr) = 4.4 and thickness (h) = 1.6 mm. The antenna realization results show that the antenna has bandwidth = 510 MHz, return loss = -15.17 dB and VSWR = 1.15. The AMC integrated bowtie antenna radiation pattern produces a unidirectional pattern with gain = 4.2 dB. However, the ringing level becomes high by -19.18 dB. Further development is needed to achieve ringing level values that meet the GPR antenna system specifications.

Realization of reconfigurable filtering horn antennas using active frequency selective surfaces for GSM and LTE signal filtering

Realization of reconfigurable filtering horn antennas using active frequency selective surfaces for <scp>GSM</scp> and <scp>LTE</scp> signal filtering

Metasurfaces for Reconfiguration of Multi-Polarization Antennas and Van Atta Reflector Arrays

This paper discusses the application of metasurfaces for three different classes of antennas: reconfiguration of surface-wave antenna arrays, realization of high-gain polarization-reconfigurable leaky-wave antennas (LWAs), and performance enhancement of van Atta retrodirective reflectors. The proposed surface-wave antenna is designed by embedding four square ring elements within a metasurface, which improves matching and enhances the gain when compared to conventional square-ring arrays. The design for linear polarization comprises of a 1 × 4 arrangement of ring elements, with a 0.56λ spacing, placed amidst periodic patches. A 2 × 2 arrangement of ring elements is utilized for reconfiguration from linear to circular polarization, where a similar peak gain with better port isolation is realized. A prototype of the 2 × 2 array is fabricated and measured; a good agreement is observed between simulations and measurements. In addition, the concepts of the design of polarization-diverse holographic metasurface LWAs that form a pencil beam in the desired direction with a reconfigurable polarization are discussed. Moreover, recent developments incorporating polarization-reconfigurability in metasurface LWAs are briefly reviewed. In the end, the theory of van Atta arrays is outlined and their monostatic RCS is reviewed. A conventional retrodirective array is designed using aperture-coupled patch antennas with a microstrip-line feeding network, where the scattering from the structure itself degrades the performance of the reflector. This is followed by the integration of judiciously synthesized metasurfaces to reconfigure and improve the performance of retrodirective reflectarrays by removing the above-mentioned undesired scattering from the structure.

Measurement-Based Analysis and Modeling of Multimode Channel Behaviors in Spherical Vector Wave Domain

This paper establishes the analytical model and analyzes the statistical behaviors of multimode channels in spherical vector wave (SVW) domain based on the microcellular radio channel measurement in downtown Helsinki at 5.3 GHz band. The multimode channel is the representation of radio wave propagation in the form of the SVW mode coupling between the transmit and receive antennas. The multimode channel does not rely on particular realizations of antennas at link ends, since any transmitting/receiving/scattering fields associated with an antenna can be modeled as a weighted sum of SVW modes where different antennas have different mode weights. The multimode channels are converted from the plane wave channel model parameters that are extracted from measured channels of coherent snapshots along 6 different routes in Helsinki. Based on the analysis of various first and second order statistics of the multimode channels, the main findings can be summarized as follows: 1) the multimode channels are power imbalanced; 2) the envelope short-term fading statistics of the multimode channels can be described with Rician probability distributions with varying K-factors; 3) the auto-correlations of multimode channels along the spatial translation of a mobile node in a propagation environment present varying coherent distances; 4) the cross-correlations of multimode channels vary with the spatial translation too. The obtained results and the proposed multimode channel model provide invaluable insights into the design of antenna systems tailored to a specific propagation environment. Indeed, antenna systems at both link ends can be devised such that the multimode channels with higher power, larger coherent distance and smaller cross-correlation are excited resulting in multiple-input multiple-output antenna systems that exploit efficiently the degrees of freedom of the propagation channel.

Perfect Conversion of a TM Surface Wave Into a TM Leaky Wave by an Isotropic Periodic Metasurface Printed on a Grounded Dielectric Slab

This article presents an exact solution for a perfect conversion of a TM-polarized surface wave (SW) into a TM-polarized leaky wave (LW) using a reciprocal and lossless penetrable metasurface (MTS) characterized by a scalar sheet impedance, located on a grounded slab. On contrary to the known realizations of LW antennas, the optimal surface reactance modulation which is found here ensures the absence of evanescent higher-order modes of the field Floquet-wave expansion near the radiating surface. Thus, all the energy carried by the SW is used for launching the single inhomogeneous plane wave into space without accumulation of reactive energy in the higher-order modes. It is shown that the resulting penetrable MTS exhibits variation from an inductive to a capacitive reactance passing through a resonance. The present formulation complements a previous article of the authors, in which a perfect conversion from TM-polarized SW to TE-polarized LW was found for impenetrable boundary conditions. Here, the solution takes into account the grounded slab dispersion, and it is convenient for practical implementation.