Metallic Patches Research Articles

Design of a 3-Bit Circularly Polarized Reconfigurable Reflectarray

In this paper, a 3-bit circularly polarized reconfigurable reflectarray is proposed. The array consists of 64 units in an 8 × 8 configuration, with each unit containing a circular metal patch loaded with phase-delay lines and eight PIN diodes. To independently control each unit, a corresponding DC control circuit was designed and tested with the array. In the bandwidth of 3.43–3.71 GHz, the circularly polarized reconfigurable reflectarray achieved a gain of 16 dB, an aperture efficiency of 27%, an axial ratio of ≤3 dB, an operating bandwidth of 8%, and a beam scanning range of ±60°. The circularly polarized reconfigurable reflectarray can also achieve a good dual-beam radiation performance after testing. The 3-bit circularly polarized reconfigurable reflectarray proposed in this paper offers several advantages, including low loss, high aperture efficiency, a wide beam scanning range, and excellent stability in wide-angle oblique incidence. It has potential applications in low-cost phased array, satellite communications, and deep space exploration.

Angularly stable Artificial magnetic conductor (AMC) loaded circularly polarized antenna array and filter Co-Design for K-band satellite applications

This paper investigates an angularly stable artificial magnetic conductor (AMC) loaded circularly polarized (CP) antenna array and filter co-design for the K-band satellite application. The AMC array is constructed from a periodic array of square metal patch unit cells with rectangular and annular slots. The AMC unit cell has good angular stability under various incidence angles and operates in a frequency range of 18 GHz to 21 GHz. The AMC-surrounded and bandpass filter (BPF) loaded antenna array is simulated and fabricated on the single side of a 0.508 mm thick Roger/5880 substrate. The impedance matching, gain, directivity, and efficiency (%) are enhanced due to the constructive interference between AMC and antenna mutual coupling. In contrast, the axial ratio (AR) is preserved. The manufacturing of the proposed structure is comparatively less complex. Finally, based on the simulation and measured results, the suggested AMC-loaded compact, wideband, and filter-inserted array with enhanced gain and efficiency can be a good choice for the 3U satellite application working in K-band.

Design and analysis of ultra-wideband microstrip patch antenna with various conductive materials for terahertz gap

The paper explores the design and analysis of a wideband microstrip patch antenna with a metallic patch and a 3 × 3 split ring resonator (SRR) array operating in the 0.1–5 THz frequency range. The antenna's structure incorporates different conductive materials such as gold, silver, and graphene as a metallic patch. The dimensions of the metallic patch and SRR are calculated to achieve wideband operation within the desired THz range. The SRR array enhances electromagnetic resonance, thereby improving bandwidth and radiation characteristics for medical imaging. The study discusses the equivalent circuit and design equations for the microstrip patch antenna and SRR unit cell. For designing and analyzing the proposed antenna, CST Microwave Studio 2019 software have been used. Performance parameters such as return loss, bandwidth, gain, efficiency, directivity, VSWR, and radiation pattern have been evaluated. The advantages and limitations of each conductive material are evaluated to determine their suitability for THz-based medical imaging applications. The goal is to maximize the antenna's bandwidth, gain, and image resolution for medical imaging purposes. The findings highlight the performance characteristics of gold, silver, and graphene as conductive materials for medical imaging applications, facilitating the development of high-resolution, non-invasive imaging systems with improved diagnostic capabilities.

Development of microfluidically reconfigurable antenna using additive manufacturing

This research presents a microfluidically reconfigurable additively manufactured antenna. The proposed configuration demonstrates the applicability of additive manufacturing (AM) for fabricating intricate and lightweight structures. Additionally, it established the feasibility of microfluidic technology for achieving continuous frequency reconfigurability. The proposed antenna utilizes the dielectric fluid for reconfiguration, facilitated by pumping it in and out of microfluidic structures using a syringe pump. The incorporation of dielectric fluid in the channels alters the effective dielectric constant of the substrate and causes perturbations in the electric field distributions around the metallic patch. To validate the proposed idea, a prototype of the microfluidically reconfigurable 3D-printed antenna is designed, fabricated, and tested. The operating frequency is reconfigured from 2.38 to 3.49 GHz with a tuning range of 1.11 GHz, and the radiation pattern remains stable across considered cases. It is observed that measured results are in good agreement with simulated values. The prototype of the antenna design is fabricated using a single machining process, eliminating the need for traditional machining. The proposed antenna’s configuration is advantageous for various applications such as IEEE802.11b/g/n, IEEE802.15.1, and IEEE802.16.

Tuneable double negative (DNG) Tri-Hexagonal split ring resonator metamaterial for 5G application

This paper introduces a compact tuneable metamaterial (MTM) unit cell featuring a tri-hexagon and tri-square split ring resonator (THTSSSR) structure designed for 5G communication applications. Metamaterials are employed to achieve unique electromagnetic properties not found in natural materials. The design process involves the arrangement of three square rings and three hexagon rings as metallic patches on a Rogers substrate (RT 5880), measuring 7 x 7 mm2 with a thickness of 1.575 mm. The proposed design exhibits double negative (DNG) properties, with resonances in the transmission coefficient (S21) at 3.493 GHz and a bandwidth of −10 dB covering frequencies between 3.057 and 3.711 GHz. Numerical simulations conducted using finite-integration techniques (FIT) in CST Microwave Studio validate the design's effectiveness, with confirmation through the Advanced Design System (ADS). The MTM unit cell demonstrates tuneable attributes, including negative permittivity ranging from 3.39 to 5 GHz and negative permeability from 3.39 to 3.86 GHz. These findings highlight the compactness and tunability of the proposed design, making it promising for 5G communication applications.

Design of High Performance Dual-band Microstrip Patch Antenna for Wi-Fi Applications

Micro strip antennas are low-profile occupies less space and requires less power. A metal patch mounted at a ground level with a di-electric material in-between constitutes a Micro strip or Patch Antenna. In this paper, it is proposed to design a Microstrip patch antenna operating at 2.4 GHz and 5.8 GHz frequencies. The primary aim is to create a compact, easily fabricated, and high-performance antenna. It is proposed to incorporate a copper patch with strategically placed slots on an FR-4 substrate, along with a 50Ω microstrip feed line. In this paper, it is proposed to measure the VSWR, Return loss, Directivity and radiation pattern of the proposed antenna. It is proposed to design this antenna using CST Microwave studio software. Top of Form Keywords: Microstrip Patch Antenna, Wi-Fi, Dual-Band, 2.4/5.8 GHz, CST Simulation

A high sensitivity planar electric–magnetic isolated sensor for full characterization of magneto-dielectric materials

Magneto-dielectric (MD) materials have received much attention due to their applications in design of high-performance antenna and microwave components. Usually, their permittivity and permeability are key parameters in design of these components. Unfortunately, full characterization of these parameters faces challenge of measurement coupling between permittivity and permeability. To address this issue, an electric and magnetic isolated sensor based on a planar resonance structure is proposed and verified. Several shorting pins are used to separate the electric and magnetic regions, which effectively reduces the measurement coupling between permittivity and permeability. These shorting pins form a magnetic cavity pins (MCP) structure. The resonance structure is used for permittivity measurement, and the MCP structure is designed for measuring permeability with enhanced sensitivity. Moreover, to further improve the quality factor, a metal patch and two 50 Ω chip resistors are integrated on the microstrip line. To extract the imaginary part, the quality factor calculated from S21 will be used. By integrating these techniques, the sensor developed in this paper provides possibility of full characterization of MD materials with high sensitivity. Moreover, the magnetic cavity provides more space than the original design, allowing measurement in the Ultra-Wideband (UWB) range possible. Two sensors are designed and fabricated for validating the sensitivity and accuracy. Several materials with different permittivity and permeability are measured. The extracted measurement values show high agreement with the reference values. The permeability errors for real and imaginary parts are smaller than 3% and 4.5%, respectively. And the permittivity errors are smaller than 2.6% and 6.4%.

Tensor-Free Holographic Metasurface Leaky-Wave Multi-Beam Antennas with Tailorable Gain and Polarization.

Recently, the community has seen a rise in interest and development regarding holographic antennas. The planar hologram is made of subwavelength metal patches printed on a grounded dielectric board, constituting flat metasurfaces. When a known reference wave is launched, the hologram produces a pencil beam towards a prescribed direction. Most earlier works on such antennas have considered only a single beam. For the few later ones that studied multiple beams, they were achieved either by having each beam taken care of by a distinct frequency or by partitioning the hologram, thereby depriving each beam of the directivity it could have had it not shared the holographic aperture with other beams. There have been recent studies related to the use of tensor surface impedance concepts for the synthesis of holograms which have attained control over the polarizations and intensities of the beams. However, this approach is complicated, tedious, and time-consuming. In this paper, we present a method for designing a planar holographic leaky-wave multi-beam metasurface antenna, of which each simultaneous beam radiating at the same frequency towards any designated direction has a tailorable amplitude, phase, and polarization, all without hologram partitioning. Most importantly, this antenna is exempted from the need for the cumbersome technique of tensor impedance. Such features of beam configurability are useful in selective multiple-target applications that require differential gain and polarization control among the various beams. Only a single source is needed, which is another benefit. In addition, effective methods to mitigate sidelobes are also proposed here. Designs by simulations according to the method are herein validated with measurements performed on fabricated prototypes.

A heteropolarized single layer reflect‐transmit‐array antenna

AbstractA novel reflect‐transmit‐array antenna is proposed in this paper, in which a single‐layer heteropolarized element with a thickness of 0.1 at 11 GHz, consisting of only two layers of metal patches printed on a dielectric substrate and six metal vias, can integrate reflection and transmission modes in the same frequency band by reasonably distributing the positions of the reflection and transmission parts in the element. We designed, fabricated, and measured the reflect‐transmit‐array antenna with an aperture of 501.2 mm2. At 11 GHz, the maximum gain of reflection is 17.7 dB, and the peak gain of transmission is 20.4 dB, indicating that this scheme has good application prospects in bidirectional wireless communication.

The design and decoupling of TX/RX antenna with omnidirectional conical beam operating at V band

Abstract In this work, a high isolation transmitter–receiver antenna with omnidirectional conical beam operating at 61.5 GHz is presented. The proposed dual-antenna system consists of a transmitter (TX) antenna and a receiver (RX) antenna with the same structure, composed of a circular metal patch with ring slot and metal shorting vias, fed by a coaxial probe at their respective geometric center. And both antennas are placed on a circular metal platform, positioned symmetrically with each other. To increase the isolation between them, three different decoupling methods are proposed, and the one with an electromagnetic band gap (EBG) structure added in-between shows the most promising decoupling effect, as the surface wave current can be maximally suppressed. The overall size of the antenna system is 2.2552 × π × 0.579 λ 0 3, where λ 0 is the free space wavelength at 61.5 GHz. A prototype of the proposed antenna system with EBG decoupling structure is fabricated and measured, demonstrating that the TX–RX isolation is 57.9 dB at 61.5 GHz, 21.6 dB better than that without decoupling structure, with omnidirectional conical beam radiation achieved at the same time.

Smart city compatible thin film solar cell based on extraordinary transmission and metallic patch nanoantenna

An effective performance enhancement model for the thin film solar cell conjointly based on extraordinary transmission and nanoantenna is proposed and investigated. The absorber layer of the extraordinary transmission based solar cell contains a metallic thin film with periodic holes. Maximum extraordinary transmission is accomplished as the metallic film has the same refractive index on both sides. Increased light transmission causes the absorber layer to absorb more light, which increases short circuit current density and subsequently the efficiency of the thin film solar cell. The presented analysis demonstrates that adding a square nano patch on the top surface of the absorber layer can further boost the extraordinary transmission. The extraordinary transmission is increased because of the formation of cavity nanoantenna. Cavity nanoantenna increases the coupling of light into the hole due to the excitation of surface plasmons polaritons. The proposed design of solar cell exhibits around 98% absorption and the short circuit current density is increased by a factor of 3.23. The study has been carried out using finite difference time domain (FDTD) method.

High-Order Wideband Band-Pass Miniaturized Frequency-Selective Surface with Enhanced Equivalent Inductance

To extend the wideband performance of high-order band-pass filtering applications, optimized designs with knitted structures based on traditional miniaturized frequency-selective surfaces (FSSs) are proposed in this paper. The presented miniaturized FSSs consist of multiple metallic capacitive layers, knitted inductive layers, and substrates. In contrast to the conventional high-order miniaturized FSSs composed of metallic frames, patches, and substrates, the optimized miniaturized FSSs replace the original metallic wire frames with knitted structures. Both proposed modified miniaturized FSSs achieve a flat pass-band from 5.5 GHz to 10.3 GHz with a 3 dB bandwidth of 71.6% under vertical incidence. The unit cells have dimensions of 0.16 λ0 × 0.16 λ0 × 0.284 λ0 and 0.16 λ0 × 0.16 λ0 × 0.279 λ0, respectively, where λ0 is the free space wavelength at 7.9 GHz, which is the center frequency of the operating band. Numerical simulations and measurements demonstrate that the proposed modified miniaturized FSSs exhibit excellent wideband performance with clean transition bands around the pass-band during oblique incidence and are suitable for applications such as radomes, where wideband filtering is essential for covering multi-band functions of radar or communication instruments.

Parametric Modeling for Curved Slots of Vivaldi Antenna Based on Artificial Neural Network

This paper proposes an artificial neural network (ANN) model based on parametric modeling for curved slots of the Vivaldi antenna. A more effective processing method is achieved by feeding ANN with the point positions that produce curved edges via cubic spline interpolation rather than the picture of metallic patches. The predicted results of ANN, including S-parameter and gain, agree well with those from the full-wave simulation. With the trained model, a Vivaldi antenna with the lower cut-off frequency is optimized by the multi-objective genetic algorithm.

Miniaturized wideband metasurface antenna loaded with H‐slot based on characteristic mode analysis

AbstractAn H‐slot loaded metasurface (MTS) structure has been developed for the purpose of constructing a miniaturized wideband metasurface antenna (MTSA). The MTS is composed of an array of 3 × 3 rectangular small metal patches, each of which is loaded with an H‐slot. The inclusion of the H‐slot significantly lengthens the current path on the small metal patch, resulting in a small antenna size. Since the direction of the effective total current does not change, the radiation performance of the antenna is almost unaffected. To excite the MTS resonance and generate a stable radiation pattern while decreasing the backward radiation, an L‐probe with an intact ground is employed. Characteristic mode analysis (CMA) is applied to reveal the miniaturization mechanism of the MTS and guide modal excitation. The prototype is fabricated and measured within a compact radiation aperture size of 0.35λ0 × 0.29λ0 (λ0 is the free‐space wavelength at the center operating frequency). The measured −10 dB impedance bandwidth is 20.16% (5.22–6.39 GHz), with a peak gain of 6.28 dBi and a front‐to‐back ratio is larger than 20 dB.

Experimental validation of group delay in a multi-window electromagnetically induced transparency metasurface

Metasurface analogs of electromagnetically induced transparency (EIT) are attracting sustaining attention due to their ability to maintain transparency windows accompanied by extreme dispersion of propagating waves, which are important for slow light devices and highly sensitive optical sensors. In this paper, we study theoretically, numerically, and experimentally the conditions for the existence of multi-band transparency windows in the metasurface supported by the interaction of dipole modes in an asymmetric unit cell. The unit cell is composed of a single bright resonator and several dark resonators made in the form of rectangular metal patches. The manifestation of EIT is studied for different metasurface configurations by varying the number and positions of resonators used within the unit cell. To validate the slow-down effect caused by EIT, a prototype of the metasurface is fabricated and tested, providing a measurement of the group delay and bandwidth-delay product features. The obtained results clearly confirm the presence of four EIT-like transparency windows in the metasurface transmission spectra originating from the coupling between either quasi-TE or quasi-TM modes of the resonators.

A Quad-Band Highly Selective Frequency Selective Surface with Ultra-Wideband Rejection.

In this paper, a highly selective quad-band frequency selective surface (FSS) with ultra-wideband rejection is presented. The proposed FSS structure was developed by cascading five metallic layers by three thin dielectric substrates. The five metallic layers are composed of two bent slot layers, two metallic square rings, and a metal patch. The dimensions of the unit cell are 0.13λ0× 0.13λ0× 0.18λ0 (λ0 is the free-space wavelength at the first operating frequency). The proposed structure achieves four transmission bands and has two wide stop-bands located at 1 to 5.5 GHz and 14 to 40 GHz, with a suppressed transmission coefficient below -20 dB. In order to verify the simulation results, an FSS prototype was fabricated and measured. It can be observed that the measured results are in favorable agreement with the simulation results. Its multiple narrow passbands and highly selective and ultra-wideband rejection properties ensure that our design can play a significant role in narrowband antennas, spatial filters, and many other fields.

Frequency-multiplexed multifunctional coding metasurface based on transmission and reflection modes

In this work, a frequency-multiplexed multifunctional coding metasurface is proposed, which can realize focusing lens at the lower frequency and multiple scattering beams at the higher frequency. The two functions can be manipulated independently. The proposed metasurface is composed of the top metal patch with a circular ring, two fan rings and two rectangle patches (CFRP), the bottom metal patch with C-shaped and rectangular metal slots (CRS) and a dielectric substrate. By changing the opening direction and size of CRS and the tilt direction and fan ring size of CFRP, the amplitude and phase of transmission and reflection can be modulated, respectively. The transmission mode works at 7 GHz, which can form focal points in different focal planes. The reflection mode works at 17.5 GHz, which can form multiple scattered beams in different directions in the far field. To further verify its practical feasibility, the proposed metasurface is fabricated and measured, the experimental results are in good agreement with the numerical simulation results. The proposed metasurface provides new possibilities to develop multifunctional devices.

Multifunctional coding metasurface for focusing and beam deflection based on polarization selection

ABSTRACT In this paper, a full-space multifunctional coding metasurface (MS) with reflection and transmission integration is proposed to realize the independent manipulation of electromagnetic waves at two different frequencies. The unit consists of two layers of dielectric substrate and three layers of metal patch, the upper reflective layer is composed of a ring and a split ring (URSR), the middle layer is a split ring groove (MSR), and the lower transmission layer is a split ring (LSR). The transmission mode works at 13.4 GHz, incoming linear polarization (LP) waves to realize beam deflection with a deflection angle of 34°. While the reflection mode works at 17.9 GHz, beam focusing to achieved under the action of circular polarization (CP) waves. In order to verify the feasibility of the design, a circularly polarized antenna is placed at 80 mm in the metasurface -Z direction, and the gain increases from 7.5 dB to 22.5 dB. Meanwhile coding metasurface and circularly polarized microstrip antennas is fabricated and measured, and the results are consistent with the simulation results. The proposed method provides the possibility of high-rate transmission of information of multifunctional devices in communication systems.

DUAL-BAND BANDSTOP FILTERS BASED ON ULTRA THIN FREQUENCY SELECTIVE SURFACES

In this paper, we present designs for terahertz filters with two independent stopbands based on periodic metallic resonant structures patterned on the dielectric substrate. Two simple and thin structures are proposed to realize required characteristics for single-polarized and dual polarized filter designs. To realize single polarized one, a unit cell of the proposed periodic structure consists of two sets rectangular shape conducting metal patches patterned on the top of the dielectric substrate, and the dual-band response is due the lattice resonances observed in the unit cell. To realize dual polarized filter design, a modified unit cell is considered with additional patches on the bottom of the dielectric substrate. The patches on the bottom layer are the same ones as on the top layer but orthogonally oriented. For this case, polarization-independent frequency response can be obtained after geometric optimization of the unit cell because the top and the bottom layers resonantly interact with only the TE or TM incident plane wave to minimize cross coupling effects between the layers. In order to intensively understand the transmission performance of the proposed filters, a large number of simulations using integral equation method are performed based on the different values for permittivity, period of the unit cell, dielectric thickness, and geometric dimensions. The electric field distributions are analyzed to understand the mechanism of the resonance behavior.

Analytical Modeling of Microwave Transmission Through Metasurfaces Made of Perforated Metal Plates, Arrays of Metal Patches, and Wire Grids

Analytical Modeling of Microwave Transmission Through Metasurfaces Made of Perforated Metal Plates, Arrays of Metal Patches, and Wire Grids