Surface Current Distribution Research Articles

Wideband star-shaped antenna based on artificial magnetic conductor surface for unidirectional radiation

Gathering the advantages of low profile, high gain, high efficiency, and wideband operation in a planar antenna is a challenging objective for the antenna designer. Low profile wideband antennas are usually characterized by low gain. An antenna of wideband impedance matching usually suffers continuous variations of the gain over such a wideband due to the variation of the radiation mechanisms and surface current distributions over the frequency band of impedance matching. Therefore, the motivation of the present work is to provide both impedance matching and stabilized high gain by the aid of wideband artificial magnetic conductor (AMC) with a design of the unit cell that is suitable to the antenna structure and the desired frequency band. The present work, proposes the utilization of low-size wideband AMS surface (AMCS) to be placed behind a wideband omnidirectional antenna to enhance the gain over the frequency band of operation. In this way, the radiating structure combines high gain and wideband operation in the same design. A wideband planar monopole printed antenna is designed to operate as omnidirectional antenna with perfect impedance matching and radiation efficiency over the frequency band 3.6-7.2GHz when placed in free space. The gain of the free-standing antenna varies from 2dBi to 4.5dBi over the frequency band. A wideband AMCS is designed to enhance the antenna gain over frequency band of operation. The designed AMCS is composed of only 3×3 unit cells and overall dimensions of 10×10cm. This surface is placed parallel to the planar antenna at a distance 1.7cm behind it. The enhanced gain of the radiating structure of the AMCS-backed antenna reaches 8.5dBi without affecting the bandwidth over which the input impedance is matched to the feeding line. The radiation efficiency of the AMCS-backed antenna is maintained above 98% over the frequency band of operation (3.7-7.2GHz). The wideband antenna and the AMCS are fabricated for practical evaluation of the overall AMCS-backed antenna performance including the measurements of impedance matching, gain and radiation efficiency. The measurements and simulation results are in good consent.

Reconfigurable frequency selective surface based absorber realized using interlocking blocks

Abstract A reconfigurable frequency selective surface (FSS) based absorber structure has been designed using a novel, cost-effective, simple to operate and easy to fabricate 3D printed interlocking blocks. Four different topologies have been investigated and validated through simulation and experimental studies. The basic geometry comprises a 3D printed mounting board, on which different blocks can be attached using interlocking studs. The frequency reconfigurability has been obtained by mechanically changing various resonating blocks on the board, which results in four distinct absorption frequencies at 4.89 GHz, 4.02 GHz, 2.92 GHz and 2.25 GHz achieving the absorptivities of 98.92 %, 96.52 %, 99.3 % and 99.5 % respectively in S and C bands. The absorption characteristics are further justified by evaluating the surface current distribution and impedance responses. The prototypes have been fabricated and tested, and they have attained a good agreement with the simulated responses. The absorption characteristics and operational frequencies remain the same, for all four cases during variations in the polarization angle for oblique incidence for both TE and TM polarizations up to 45°, as studied in the simulation. These have been experimentally verified up to 30° for TE polarization, thereby demonstrating the polarization-independent and angularly stable responses.

Design of band reconfigurable Koch fractal antenna for wideband applications

In this communication, a band reconfigurable fractal antenna with modified partial ground is proposed for wireless applications. Four switches using PIN diodes supported by the antenna biasing circuit provide frequency reconfigurability, while star-shaped fractal geometry is used to achieve both miniaturisation and wideband functioning in the proposed antenna. The surface current distribution of the radiating patch is altered by the ON and OFF states of the PIN diode, which leads to the multiband resonance and reconfiguration features of the designed structure. The designhas an overall electrical size of 70 × 45 × 1.6 mm3 and is made on a commonly available FR4 substrate with a thickness of 1.6 mm and a dielectric constant of 4.4. The three operational bands are as follows: case I, which covers 3.7–5 GHz (30 %); case II, which covers 1.7–3.5 GHz (71 %); and case III, which covers 1.4–4 GHz (96 %). Two distinct bands are obtained in cases I and II; and case III nearly covers the frequency band of cases I and II. Therefore, the impedance bandwidth (IBW)offers continuous wideband frequency coverage from 1.4 to 5 GHz (110 %). To sense the full band and then modify its bandwidth to choose the appropriate sub-band and prefilter out the others, the proposed antenna may switch between a wide operational band of 1.4–5 GHz with three distinct subbands. The antenna could potentially be useful for wireless communication systemsin the future due to its frequency-selective feature and stable radiation patterns.

Electric and magnetic resonances inducing triple-stopband terahertz metamaterial filter

A polarization insensitive triple-stopband terahertz metamaterial filter is proposed. This filter consists of a flexible polyimide substrate and periodically arranged copper structures on its top. The shape of the metal unit is a “田” inside a square ring. The simulation results show that the resonant frequencies of the filter are 0.107, 0.23, and 0.271 THz; the stopband depths are −35.56 dB, −42.7 dB, and −37.485 dB; the 3 dB bandwidths are 34, 53, and 32 GHz; and the relative bandwidths are 31.78%, 23%, and 11.8%, respectively. Effective parameter analysis demonstrates that the first resonance originates from the negative effective permittivity and positive effective permeability, but the reason for the latter two resonances is opposite to the first. The surface current distributions indicate that the first resonance is electric type, while the latter two resonances are the lower and higher orders magnetic resonances, respectively. Then, we verify the triple-stopband characteristic of the filter based on the equivalent circuit. Finally, the analysis reveals that the performance of the filter is independent of the incident polarization angle. This filter has the characteristics of multi-frequency, broadband, deep stopband, polarization insensitivity, and simple structure, which can be used in terahertz communication, detection, and other fields.

High efficient bi-functional metasurface with linear polarization conversion and asymmetric transmission for terahertz region

Abstract Polarization control is crucial in contemporary photonics, but achieving broad bandwidths and high efficiencies remains a significant challenge. Here, we propose a wideband and high-efficiency metasurface designed for linear polarization conversion and asymmetric transmission (AT) in the terahertz region based on a three-layer chiral structure. By integrating a double-split ring and strip resonator, the design can improve both wide bandwidth and high-efficiency cross-polarization conversion and AT capabilities for a linearly polarized wave. The operating band for AT is 0.73-3.01 THz with an efficiency above 0.8, while the polarization conversion ratio exceeds 0.99 across the 0.56-3.94 THz range. The underlying physical mechanism behind wideband transmission polarization conversion was fully elucidated through theoretical analysis and the characterization of surface current distribution. This designed structure can be used in terahertz imaging, sensing, and communication.

Design of Band Stop Filter Using Epsilon-Negative Frequency Selective Surface

This paper focuses on designing a band stop filter based on epsilon-negative frequency-selective surface (FSS). The unit cell has an electrical length of 0.104λ0 × 0.104λ0 which offers a bandwidth of 2.53 GHz from 1.24 GHz to 3.77 GHz. It has a center frequency of 2.44 GHz and the obtained fractional bandwidth is above 100%. Additionally, the behavior of the presented FSS is explained by the equivalent circuit model and surface current distribution. Within the entire bandwidth, it offers a negative permittivity. The refractive index of BSF is almost zero for 2.45−3.98 GHz range of frequency. The proposed FSS structure exhibits polarization-independent properties and offers a stable frequency response for normal and oblique angles under both TE and TM polarization. Good agreement between the simulated and measured results is obtained for the designed prototype.

An adaptive assisted method based on MOPSO for THz MMA effective designing

Abstract To address the high time cost and low efficiency of traditional terahertz metamaterial absorber design, an adaptive method based on multi-objective particle swarm optimization was proposed. First, we presented a symmetric absorber of a four-split-ring resonator with a cross-shaped top layer. The structural parameters were optimized by the particle swarm optimization and multi-objective particle swarm optimization algorithms. The simulation results indicated that the multi-objective particle swarm optimization rapidly obtained geometric parameters that balance the high absorptivity and high quality factors. This method quickly identified a symmetric structure with absorptivity greater than 99% and quality factor of 377.45 at 1.584 THz. Additionally, the asymmetric structure achieved near-perfect absorption at 1.585 THz with a Q value of 281.32. By studying the electric field distribution and the surface current distribution, the physical mechanism of the absorber designed has been explained. This adaptive assisted method based on multi-objective particle swarm optimization can efficiently design metamaterial absorbers and offer an artificial intelligence strategy for terahertz functional device design.

Single layer vanadium oxide assisted switchable metasurfaces for transmissive and reflective polarization conversion

Polarization control using metasurfaces is highly advantageous; however, most metasurfaces operate exclusively in either transmission or reflection mode. Additionally, achieving both wide bandwidth and high efficiency simultaneously in their design remains a significant challenge. Here, we design a high-efficiency and wideband switchable metasurface that can switch between transmissive and reflective polarization conversion modes by utilizing a single layer of I-shaped resonators and gold-vanadium dioxide (VO2) alternating gratings printed on a quartz substrate. When VO2 transitions to its metallic phase, the continuous metal layers of gold-VO2 eliminate transmission and the designed metasurface operates as a reflective cross-polarization converter with a polarization conversion ratio (PCR) exceeding 0.9 over a broad frequency range of 1.4–3.3 THz. Conversely, when VO2 is in its insulator phase, the THz incoming wave can transmit through the gratings, and the design behaves as a transmissive cross-polarization converter with a PCR above 0.99 in the 0.75-4.0 THz range for a forward y- polarized wave. The working mechanism for both transmissive and reflective polarization conversion modes is explained through theoretical analysis and surface current distributions. With the advantages of facile design, high performance, and dual functionality, our design is expected to be applied in the fields of imaging, sensing, and communication.

Halvorsen chaotic system based microwave absorber modelling for fighter jet stealth technologies

This study focuses on the development and detailed analysis of a broadband microwave absorber utilizing Halvorsen chaotic dynamics, that focuses at enhancing stealth capabilities for fighter jets. The investigation begins by exploring the mathematical formulation of the Halvorsen chaotic system and conducting a parametric sweep of its control parameters to generate distinct two-dimensional and three-dimensional chaotic attractor plots. These plots are then post-processed using Julia set theory to develop intricate fractal patterns, which serve as the foundation for the absorber design. Image processing techniques, including filtering and thresholding, are employed to refine the patterns by removing artifacts and noise, ensuring they are suitable for practical implementation. The refined fractal patterns are then imported into a computational electromagnetic simulation environment where they are patterned onto a 0.035 mm thick copper sheet. Moreover, the Magtrex 555 substrate with a thickness of 1.52 mm, is selected for its high permittivity and low-loss characteristics. A comprehensive series of parametric studies are conducted to evaluate the influence of various design parameters such as side length, unit cell geometry, and substrate thickness on the absorber’s electromagnetic performance. Important parameters include the effects of chaotic control parameter optimization and the electromagnetic boundary conditions applied during the simulations. Extensive simulations are performed across the 2–20 GHz frequency range to evaluate absorption efficiency, focusing on key metrics like absorptivity, surface current distribution, and electric field distribution. The final design achieves over 90 % absorption efficiency within the target frequency band when the chaotic control parameters are optimized. Finally, comparative analysis using different commercially available substrates, including FR-4 and Rogers RO3003, reveals that Magtrex 555 offers superior absorption performance. The study concludes with a detailed presentation of the final absorber design, alongside an indepth discussion of the frequency range, parametric variations, and the impact of chaotic system dynamics on the absorption properties. This research provides crucial insights into the design and optimization of chaotic-system-based microwave absorbers, that advances the development of stealth technology in military applications.

Wide angle wide band polarization insensitive metamaterial absorber for C, X and Ku band application with hexagonal packaging

Abstract In this paper wide angle wide band polarization insensitive Metamaterial absorber (MA) has been proposed. The proposed unit cell structure consists of hexagonal concentric ring along with hexagonal packing. The structure is fabricated on FR4 substrate. The advantage of hexagonal packing is that it covers less area as compared to square packing. The unit cell structure is scaled w.r.t hexagonal ring and resistance of the substrate. The absorptivity achieved range from 6.54 to 14.85 GHz having Bandwidth (BW) of 8.31 GHz. The metamaterial behaviour of the structure is proven by plotting real and imaginary pat of permittivity and permeability. Absorption mechanism is shown by plotting surface current distribution at the top and bottom of the surface. The proposed MA structure is analysed for normal and oblique incidence. From the normal incidence it was found that structure has wide angle polarization insensitive. The absorptivity of the fabricated structure is measured inside the anechoic chamber. The simulated and measured plot is compared and found that both the results are very close to each other. At last, the proposed and already reported MAs are compared and from the observation it was found that proposed unit cell have larger BW compact in size, polarization insensitive and have hexagonal packing. The proposed MA covers partial C band, full X band and partial Ku band. The Proposed MA found practical applications for satellite communication, Wi-Fi devices, cordless telephone, military, air traffic control, defence tracking, vehicle speed detection.

Small-Size Eight-Element MIMO Metamaterial Antenna with High Isolation Using Modal Significance Method.

This article presents a symmetrical reduced-size eight-element MIMO antenna array with high electromagnetic isolation among radiators. The array utilizes easy-to-build techniques to cover the n77 and n78 new radio (NR) bands. It is based on an octagonal double-negative metamaterial split-ring resonator (SRR), which enables a size reduction of over 50% for the radiators compared to a conventional disc monopole antenna by increasing the slow-wave factor. Additionally, due to the extreme proximity between the radiating elements in the array, the modal significance (MS) method was employed to identify which propagation modes had the most impact on the electromagnetic coupling among elements. This approach aimed to mitigate their effect by using an electromagnetic barrier, thereby enhancing electromagnetic isolation. The electromagnetic barriers, implemented with strip lines, achieved isolation values exceeding 20 dB for adjacent elements (<0.023 λ) and approaching 40 dB for opposite ones (<0.23 λ) after analyzing the surface current distribution by the MS method. The elements are arranged in axial symmetry, forming an octagon with each antenna port located on a side. The array occupies an area of 0.32 λ2 at 3.5 GHz, significantly smaller than previously published works. It exhibits excellent performance for MIMO applications, demonstrating an envelope correlation coefficient (ECC) below 0.0001, a total active reflection coefficient (TARC) lower than -10 dB for various incoming signals with random phases, and a diversity gain (DG) close to 20 dB.

Designing a Novel THz Band 2-D Wide-Angle Scanning Phased-Array Antenna Based on a Decoupling Surface

This paper proposes a novel THz band 2-D wide-angle scanning phased-array antenna (PAA) based on a decoupling surface. The simulated S11 bandwidth under periodic boundary conditions is 106–119 GHz, with stable gain within the bandwidth. The designed decoupling surface effectively reduces the coupling between elements, and the simulated active VSWR performance and ground surface current distribution under periodic boundary conditions confirm this. An 8 × 8 (64-element) planar PAA is modeled and simulated in CST2022 to verify the beam-scanning performance of the PAA. According to the simulation results, a 2-D wide-angle scanning of ±48° is achieved in the 106–114 GHz range, while in the 115–119 GHz range, a wide-angle scanning of ±48° is achieved on the E-plane, and the beam-scanning range on the H-plane reaches ±40°. Moreover, the normal peak gain is stably maintained at 21.9–22.8 dBi, with a normalized radiation efficiency as high as 95%, and the scanning radiation efficiency is higher than 81%. Due to its stable gain and 2-D wide-angle scanning performance, the proposed PAA has a broad application prospect in terahertz wireless communication equipment.

Inset-fed quad-port hexagonal-shaped MIMO T-shaped slots on patch with slots on ground plane antenna for IoT and X-band applications

A compact and novel inset-fed hexagonal-shaped multiple input multiple output patch (IHMP) antenna with T-shaped slot is designed for IoT and X-band applications. The IHMP antenna comprises with four identical hexagonal-shaped radiating elements. In order to achieve better diversity performance and low mutual coupling, radiating elements P1, P4 are positioned side by side with ideal distance and P2, P3 are positioned opposite to P1, P4. The proposed hexagonal-shaped MIMO antenna is prototyped on low-cost Fr-4 substrate with the dimensions of 28 × 28 × 1.6 mm3. It achieves dual bandwidths (S11 < −10 dB) of 1.37 GHz (2.12–3.49 GHz) and 1.69 GHz (8.07–9.76 GHz) at 2.5 and 8.7 GHz resonating frequencies. The IHMP antenna having gain of 5.68dBi, and 5.51dBi at 2.5 and 8.7 GHz, respectively. At operating frequencies, surface current distribution and radiation patterns are examined. To calculate the diversity performance of the IHMP antenna, MIMO parameters envelope correlation coefficient < 0.05 within the band, diversity gain > 9.9 within the band, total active reflection coefficient, channel capacity loss < 0.2 bits/sec/Hz, and mean effective gain −3 dB < MEG < −6 dB are also investigated. The simulated and experimentally obtained results are presented and they are in fine agreement.

A polarization conversion metasurface for broadband and high-efficiency bidirectional filtering

Here, we demonstrate a polarization conversion metasurface which is composed of a single layer square split-ring resonator and bi-layered slotted perfect electrical conductor (PEC) to realize broadband and high-efficiency bidirectional filtering. The numerical results indicate that y-polarized waves can be converted to x-polarized transmission waves in the frequency range of 6.6 GHz to 13.9 GHz, while prevent this polarized waves with frequency beyond this band, and purity x-polarized waves can be obtained as electromagnetic (EM) waves are incident along negative z-axis, meanwhile, x-polarized waves can be converted to y-polarized transmission waves and only y-polarized waves available when EM waves are incident along positive z-axis. This designed polarization conversion metasurface has the function of bidirectional filtering in a wideband frequency range. Furthermore, the broadband property can be maintained as the incident angle up to 30°. The Fabry–Pérot-like cavity model is established to clarify the interference and enhancement effect of polarization conversion, and the electrical field and surface current distributions are used to elucidate the physical mechanism of polarization conversion and filtering. The experimental results are coincident with the numerical simulations. This metasurface can be employed in controlling the filtering signal of the polarized devices and can be functional as a bandpass filter in communication systems.

Triple-frequency terahertz modulator based on electronically controllable metamaterial from the coupling effect

This paper proposes a triple-frequency terahertz amplitude modulator that utilizes an I-shaped strip and four U-shaped metal patches within a common metal-substrate configuration. The top metal layer consists of an I-shaped strip and four U-shaped metal patches, while the bottom substrate layer is made of polyimide. Amplitude modulation is achieved through adjusting the plasma frequency of the high-electron-mobility transistors, resulting in a modulation depth of nearly 93% at resonance frequencies of 0.26 and 0.49 THz. At 0.6 THz, the modulation depth reaches 65%, demonstrating excellent performance. Resonance frequencies are determined by electric field and surface current distribution. The triple-frequency terahertz amplitude modulator is applicable in various fields, including terahertz communications and imaging.

Development, characterization and validation of a novel physics-informed equivalent circuit model for silicon–graphite battery cells

The widespread deployment of electric vehicles (EVs), as well as the growing requirements both from manufacturers and consumers, necessitate an increase in energy density with regard to current lithium-ion batteries (LIBs). In this regard, one of the most promising alternatives is the addition of silicon to conventional graphite anodes, thus giving rise to energy-dense LIBs. However, this entails a significant increment in modeling, parameterization and computational complexities due to the interactions between both negative electrode materials. In this article, we present a novel physics-informed equivalent circuit model for cells with blended electrodes, which is able to provide accurate results with respect to a state-of-the-art electrochemical model, not only for the output voltage (≤25 mV RMS), but also internal states, namely active material particle surface concentrations (≤1.2 %) and current distribution (≤2.6 %) at a much lower computational cost. Furthermore, this formulation also allows for a notable simplification of model parameterization. Hence, we describe thorough static and dynamic parameterization processes from half-cell experimental data and impedance measurements. Finally, we validate the proposed model in constant-current as well as dynamic operation, highlighting the influence that the choice of hysteresis model has on the latter. We understand that the presented model is an interesting alternative for the modeling of cells with blended electrodes, and is also suitable for its implementation in Battery Management Systems (BMSs) in EVs.

Design of high flexible multi-band conformal printed patch antenna for sub 6 GHz 5G-based vehicular communication

ABSTRACT Vehicular communications (VCs) play a major role in intelligent transportation systems (ITS). In addition to preventing unintentional collisions and traffic jams, this system can lower fuel and energy usage in the transportation system. The Internet of Vehicles emerges by integrating the IoT with vehicles for smooth communication. In IoV, vehicular communications may be from vehicle to infrastructure (V2I), vehicle to vehicle (V2V), vehicle to pedestrian (V2P), and vehicle to network (V2N) or vehicle to roadside unit (V2R). The antenna used in vehicular communication has some problems, such as less efficiency and high return loss. The frequency response in the existing methods should not give sufficient data for selecting a better band. To avoid this kind of issue and improve the performance by selecting a better frequency band, this work presents a highly flexible multi-band conformal printed patch antenna for sub-6 GHz 5 G-based vehicular communication application. The substrate used to design the antenna is polyimide, and the microstrip patch antenna is designed with cross-shaped slots. The multi-band circularly polarised antenna is designed to operate in vehicular communication bands such as 2.4 GHz, 4.7 GHz, 5.3 GHz, and 5.9 GHz. The proposed work is simulated in HFSS, and the results of directivity, gain, reflection coefficient, Voltage Standing Wave Ratio (VSWR), radiation pattern, axial ratio, Left-Hand Circular Polarisation (LHCP), Right-Hand Circular Polarization (RHCP) and surface current distribution are evaluated for the conformal antenna.

An ultra broadband metamaterial absorber based on metal-dielectric-metal technology for THz spectrum

This paper introduces a novel ultra-broadband Metamaterial Absorber (UBMA) demonstrating significant absorption capabilities across a wide terahertz frequency range from 2.42 THz to 6.11 THz. The 3.7 THz bandwidth represents 87% of the central frequency. The proposed UBMA comprises three layers: a star-shaped metal patch on top, a dielectric substrate in the middle, and a metallic ground plane below. Simulations using CST Microwave Studio software reveal that the design achieves high absorption at five distinct frequencies: 2.47, 3.45, 4.89, 6.01, and 6.87 THz, with absorption rates of 99% for the first four peaks and 90% for the fifth peak. The study of electric field and surface current distribution provides insights into the absorption mechanism. While the UBMA exhibits polarization-independent performance, its angular response shows some sensitivity to the incident angle, especially beyond 30° Despite this, the absorber maintains over 70% absorptivity up to a 45° incidence angle for both TE and TM polarizations within specific frequency ranges. The simple structure combined with high absorption efficiency makes the UBMA suitable for THz imaging, detection, and stealth applications, although its angular sensitivity must be considered for certain applications.

A new miniaturized Split-Ring Resonator-Based inverse double Sigma-Shaped artificial material for Penta-Band wireless communication

This paper discusses a study on creating and confirming the authenticity of an artificial material with a SNG (Singular Negative) attribute. The artificial material was constructed using a metamaterial structured around split-ring resonators forming an inverse double sigma shape. Advanced electromagnetic simulation tools like CST (Computer Simulation Technology) Microwave Studio, Ansys HFSS (High Frequency Structure Simulator) and ADS (Advanced Design System) were employed to extensively analyze the electromagnetic characteristics of the artificial material. Notably, the proposed artificial material exhibits five distinct resonance frequencies spanning L-, S-, C-, X-, and Ku-band operations, specifically at 1.560 GHz, 2.232 GHz, 4.350 GHz, 8.095 GHz, and 17.370 GHz. Achieving an optimal EMR (Effective Medium Ratio) of 23.45, with a compact unit cell size of 8.2 mm × 8.2 mm and a substrate thickness of 1.905 mm, underscores its innovative design attributes. Of significance, the compact size, SNG characteristics, high EMR, and resonant frequencies render this structure particularly noteworthy. The utilization of the L-band for GPS (Global Positioning System), S-band for Wireless LAN (Local Area Network), C-band for Satellite communication, X-band radar system, and the Ku-band for VSAT (Very Small Aperture Terminal) communication applications is well-documented. This article elucidates the intricacies of the design process and conducts various parametric analyses. Remarkably, the simulation results obtained from Ansys HFSS 3D software closely align with those from CST. Furthermore, a comprehensive examination of surface current, E-field, and H-field distributions is provided. Importantly, comparative assessments indicate the superior performance of the proposed structure across multiple metrics, including EMR, SNG frequency range, and compactness, positioning it as an ideal candidate cellular phone, satellite, and radar-based applications.

A Miniaturized High-Gain Router Antenna Pair for 2.4 GHz and 5.0 GHz Frequency Bands

In this paper, we propose a printed circuit board (PCB)-based planar antenna pair, operating at 2.4 GHz and 5.0 GHz frequency bands, respectively, for dual-band routers. The antennas are both rectangular and consist of twisted radiating elements and microstrips etched on an FR4 dielectric substrate. Etching slots on the radiating elements and adjusting the serpentine microstrips influence surface current distribution and therefore effectively reduce antenna size and enhance antenna gain. The proposed antenna features a compact size compared to general router antennas and demonstrates high gain characteristics compared to dipole antennas. In the 2.3–2.5 GHz band, the simulated S11 of the 2.4 GHz antenna was lower than -10 dB, while the gain was 3.9 dBi at 2.4 GHz. In the 5.1–5.9 GHz band, the simulated S11 of the 5.0 GHz antenna was lower than -10 dB, and the gain was greater than 4.8 dBi. The proposed antenna has potential for application to router antennas.