Maximum Antenna Gain Research Articles

Design of an ultra wideband THz reflectarray antenna based on orbital angular momentum

A Reflectarray antenna (RA) that can generate orbital angular momentum vortex waves in the THz band was proposed. First of all, a reflective phase-shifting element composed of a notched double-shaped ring and a single Matal structure was designed to form a radiation patch. The reflective phase-shifting element has the advantages of good linearity, high smoothness, and a large phase shift range, which is suitable for the subsequent production of reflective array antennas. Then, the phase distribution of the reflected wave of the OAM vortex wave carrying mode l=+1、+2、+3、+4 is given, and the size of each element is determined based on the reflected phase of each element. Using the proposed element, an OAM reflectarray antenna operating within the waveguide standard WR-5 (120GHz–220GHz) is designed. The optimal frequency band for antenna operation in mode l=+1 is 150GHz–190 GHz, and the maximum gain of the reflector array antenna is 19.4 dBi, and the minimum divergence angle of the antenna array is 5.2°, which has good directivity and beam radiation ability. The spiral structure of the OAM beam space generated by the RA in this paper is clearly visible, proving that the implementation of OAM vortex waves in the THz frequency band is feasible. This design also provides a new method for generating OAM vortex waves in wireless and microwave wireless communications. The proposed RA is suitable for 6G wireless communication systems.

Gain-enhanced and Mechanical Reconfigurable Slot Antenna with Metasurface

A novel wideband slot antenna with metasurface is presented. In order to achieve broadband, high-gain, and mechanical reconfigurable performance, a metasurface is adopted and combined with a new-type planar slot antenna The antenna and metasurface are designed on F4B substrate, and the overall dimension of the antenna is 1.48λ0×1.48λ0×0.2λ0 (λ0 is the free space wavelength at center frequency). Different from the traditional square metasurface, a structure with different properties in the x and y directions is utilized in the proposed antenna, which can be reconstructed by adjusting the relative position between the slot antenna and the metasurface. By introducing the metasurface, the maximum gain of the whole antenna is improved. The antenna works in two states with respect to the two locations of the metasurface. The impedance bandwidth of the proposed antenna in state A is from 5.49 to 9.40 GHz (52.5%), and the impedance bandwidth of the proposed antenna in state B is from 5.83 to 6.01 GHz (3%) and 7.05 to 9.62 GHz (30.8%). The gain of the whole antenna in both states is higher than that of the original slot antenna (without metasurface), and the maximum gain is 9.1 dBi.

Compact Archimedean spiral antenna with high gain for electrostatic discharge detection

AbstractA compact Archimedean spiral antenna with high gain for electrostatic discharge (ESD) detection is investigated. A frustum‐shaped cavity proposed in this work is formed to optimise the maximum antenna gain. Additionally, a helix arm is loaded to enhance antenna gain in lower band. The measured results demonstrate that the proposed antenna, which employs a unidirectional radiation mode, exhibits a maximum antenna gain ranging from −0.74 dBi to 9.46 dBi and a voltage standing wave ratio less than 3 across a frequency range of 0.65–5 GHz. A test system consisted of proposed antenna and a commercial ESD detection antenna is established. The verified results indicate that the proposed antenna has a performance close to the commercial antenna, so that proposed antenna with compact size is preferred to be utilised for ESD detection.

Fabrication of compact circular ring antenna loaded with Gd-YIG ferrites: Photon–magnon interaction

In telecommunications technology, transmitting and receiving signals is not possible without an integrated antenna. Recently, novel approaches of transmitting and receiving signals using advancement in quantum technology as “information coherent transfer” have been emphasized which overcomes the limitations of superconducting qubits. In the present investigation, a compact-sized circular-ring antenna was designed for a 12 GHz centre frequency. The antenna was topped with Gd(x)-doped YIG (x = 0.0, 0.1, 0.2, 0.3) thin disks to investigate its tunable operation over the tri-band (C to Ku) frequencies due to the photon–magnon coupling, which enables coherent qubit information transmission from an electromagnetic (EM) carrier to the magnons. The proposed prototype of the antenna is validated using HFSS simulation. To characterize the frequency tunability of the designed antenna, we measured the return loss (S11) via a vector network analyzer as a function of dc magnetic field. Different concentrations of Gd-doped YIG ferrites (Gdx-YIG) have been loaded on ring antennas to observe strong anti-crossing phenomena with the application of an external magnetic field. The designed antenna has a tunability of around 300% for a small applied magnetic field up to 3.7 kOe. The maximum gain of dual resonance antenna is 1.4 for higher magnetic field of 3.7 kOe. The highest efficiency and lowest bandwidth of 30% and 14% respectively, for Gd0.1-YIG disk are observed. The measured normal mode splitting spectrum as a function of bias magnetic field that gives the maximum coupling strength is 153 MHz for a Gd concentration of 0.1. For practical applications, such antennas are suitable for use in tunable tri-band or multi-band applications (C to Ku).

A low-profile antenna with parasitic elements and a DGS-based partial ground plane for 5G/WMAN applications

A low-profile antenna with three parasitic elements is designed and presented for fifth-generation (5G) and wireless metropolitan area network (WMAN) applications. This prototype covers the frequency range of 2.75–4.94 GHz, which is applicable for the lower 5G (3.33–4.2 GHz), WWAN n48 CBRS (US) (3.55–3.7 GHz), WiMAX rel 2 (3.4–3.6 GHz), n77 (3.3–4.2 GHz, most European and Asian countries), n78 (3.3–3.8 GHz, USA), and n79 (4.4–5.0 GHz, China, Hong Kong, Japan, and Russia) bands. The prototype is made of a low-loss, commercially available substrate material known as Rogers RT 5880 (εr = 2.2, tanδ = 0.0009) with a thickness of 0.79 mm. The optimized dimension of the proposed antenna is 35 × 25 × 0.79 mm3 (i.e., 691.25 mm3). The proposed 10-element array antenna is fed by a 50 Ω feeder. The maximum gain and directivity of the prototype antenna are 4.3 dB and 4.75 dBi, respectively. The radiation efficiency of the prototype varies from 86.79 to 92.14% (simulated) and from 86.23 to 91.48% (measured), and it is 89.48% (simulated) and 90.59% (measured) at 3.225 GHz. The impedance profile of the proposed 10-element array is (49.80-j1.72) Ω, which ensures good impedance matching. The VSWR and surface current of the low-profile antenna are 1.036 and 107.931 A/m at the center frequency of 3.225 GHz, respectively. The value of the scattering parameter (S11) is − 36 dB at the resonant frequency. By using a DGS-based partial ground plane and parasitic elements, it enhances bandwidth to 2.19 GHz. Therefore, the tested prototype is an excellent candidate to be deployed for 5G/WMAN applications with respect to the different presented parametric studies.

A Broadband Double-Layer Transmitarray Antenna Based on Polarization Conversion Elements

A broadband double-layer transmitarray antenna (TA) is proposed in this letter. In order to obtain broadband performance in a double-layer structure, we use a “receiving-transmitting” (RX-TX) structure instead of a double-layer frequency selective surface. The elements of the new TA are composed with metal layers and dielectric substrate. Both the metal layer are connected by a metallized via and etched with orthogonal slots. The RX and TX layers work without interfering while converting the linearly polarized incident wave into orthogonal polarization. Phase compensation can be achieved by changing the direction and length of the microstrip meander ling. Then, a broadband TA is designed. Considering the simplicity of the design, we sequentially selected eight phase states at 45° intervals for phase modulation. The measured maximum antenna gain is 24.5 dBi. The center frequency is 10 GHz. The measured 1-dB and 3-dB gain bandwidth(BW) are 18.7% and 29.4%, respectively. The maximum aperture efficiency (AE) is 51%.

Reconfigurable CRLH‐inspired antenna based on Hilbert curve EBG structure for modern wireless systems

AbstractThis paper presents a novel antenna design with an enhanced gain‐bandwidth product for modern communication networks, including 5G systems. The design is consistent with 17 unit cells of a composite right/left‐hand (CRLH) structure with an electromagnetic band gap of Hilbert inclusions. Therefore, the resulting design occupies an area of 40 × 200 mm2 of a Taconic RF‐43 substrate. The maximum antenna gain is 16 dBi at 5.5 GHz, which is very applicable for long‐range communication systems. Nevertheless, the antenna performance is controlled with optical switches of light‐dependent resistors (LDR) technology. Therefore, the antenna performance is tested with different switching seniors to investigate the possibility of reconfiguration scenarios at various frequency bands. However, the antenna gain is highly affected by changing LDR switching status; for example, at 5.5 GHz, the antenna gain is varied between 7 and 16 dBi. Thus, the proposed antenna is an excellent candidate for direct amplitude modulation. Finally, the antenna simulation results and measurements agree very well with each other.

A Low-Cost and Dual band Microstrip Patch Antenna for Ku and K Band Applications

This paper examines a dual-band, low-cost microstrip patch antenna for Ku and K applications through simulation study. Ansys High Frequency Structure Simulator (HFSS) software is used to do the simulation analysis of the suggested antenna. Using Ansys High Frequency Structure Simulator (HFSS) software, the suggested antenna is constructed and simulated to evaluate several characteristics including reflection coefficient (S11), radiation pattern, gain, and bandwidth. The substrate for the antenna is made of FR-4, which has a relative permittivity of 4.4 and a dielectric loss tangent of 0.02. Using the microstrip feed line technology, the planned millimeter wave dual band antenna is examined at operating frequencies of 13 and 22 GHz. At frequencies of 13 and 22, respectively, the antenna's maximum gain values are 4.81 dB and 4.82 dB in the x-y plane. The suggested material might be a decent substitute.

Design of a compact magneto‐electric dipole antenna

AbstractIn this letter, a compact magneto‐electric (ME) dipole antenna is designed and analyzed without compromising too much good performance of the ME dipole. In particular, the second‐order Minkowski‐like fractal structure is loaded on the planar electric dipole to effectively miniaturize the aperture size of the antenna. A prototype was fabricated and measured. The antenna volume is reduced by 24.6% when compared with the counterpart before the fractal. Meanwhile, the proposed antenna can achieve a bandwidth of 56% in terms of −10 dB ranging from 1.58 to 2.81 GHz. The radiation pattern of E‐ and H‐planes are basically identical. The cross‐polarization level is less than −25 dB, and the front‐to‐back ratio is larger than 14 dB. The maximum antenna gain can be up to 10.1 dBi. The measured results are in good agreement with the simulated ones.

Antenna Gain-Bandwidth Enhancements Using CRLH Hilbert Fractal-based Structure

With the development of communication systems, antennas of small size and high gain have become essential to keep up with the new challenges. The metamaterials made these challenges possible. In this paper, a new low-profile metamaterials-based array is designed. The array unit cell comprises a symmetric composite right left hand (CRLH) unit cell. A third-order Hilbert curve structure replaces the VIA, and aperiodic slots are introduced between the unit cells to enhance the overall performance. This design provides a significant improvement over the original design. CST MWS was used to stimulate the design. Gain and S11 are calculated to evaluate the antenna performance; a dual- bandwidth was achieved extended from (3.72 to 3.79) GHz and (6.99 to 8.55) GHz with maximum antenna gain equal to (5.28, 7.66) dBi, respectively. The antenna is characterized by its small size and high efficiency, making it suitable for Long-Term Evolution LTE, 5G, and satellite applications.

An All-Metal, Circularly Polarized Reflectarray Antenna for High-Power Microwave Applications

In order to improve the performance of the existing high-power microwave (HPM) antenna, an all-metal circularly polarized (CP) reflectarray (RA) antenna is proposed in this article. The proposed antenna has 2-D beam-steerable capability up to 60° elevation angle. The RA element employs an H-shaped slot and can be mechanically rotated to obtain continuous 360° phase coverage with negligible element loss. By rotating the individual element, the RA antenna can achieve the dynamical control of the antenna beam. The maximum antenna gain is 33.05 dBi, corresponding to an aperture efficiency of 58.76%. In addition, the simulation results show that the power handling capacity of the RA antenna is over 5 GW/m2 under vacuum condition, which can be applied to the HPM applications.

Holographic Integrated Sensing and Communication

To overcome spectrum congestion, a promising approach is to integrate sensing and communication (ISAC) functions in one hardware platform. Recently, metamaterial antennas, whose tunable radiation elements are arranged more densely than those of traditional multiple-input-multiple-output (MIMO) arrays, have been developed to enhance the sensing and communication performance by offering a finer controllability of the antenna beampattern. In this paper, we propose a holographic beamforming scheme, which is enabled by metamaterial antennas with tunable radiated amplitudes, that jointly performs sensing and communication. However, it is challenging to design the beamformer for ISAC functions by taking into account the unique amplitude-controlled structure of holographic beamforming. To address this challenge, we formulate an integrated sensing and communication problem to optimize the beamformer, and design a holographic beamforming optimization algorithm to efficiently solve the formulated problem. A lower bound for the maximum beampattern gain is provided through theoretical analysis, which reveals the potential performance enhancement gain that is obtained by densely deploying several elements in a metamaterial antenna. Simulation results substantiate the theoretical analysis and show that the maximum beamforming gain of a metamaterial antenna that utilizes the proposed holographic beamforming scheme can be increased by at least 50% compared with that of a traditional MIMO array of the same size. In addition, the cost of the proposed scheme is lower than that of a traditional MIMO scheme while providing the same ISAC performance.

High Gain Planar Segmented Antenna for mmWave Phased Array Applications

A new high-gain antenna structure is proposed for mmWave 5G and potentially for B5G and 6G applications. The proposed antenna is configured by a planar segmented patch structure that has a radiator size comparable to the conventional patch but achieves more than 3 dB gain enhancement without a help of superstrate stack-up layer. The proposed planar segmented antenna (PSA) induces multiple magnetic currents through multiple segmented conductors, resulting in a strong magnetic field circulation around the conductors. Only one conductor requires an excitation port and each segmented conductor has a shorting pin to synchronize resonance currents. To verify the PSA operation, several prototypes were fabricated at 28 GHz with the identical volume of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.213\,\,\lambda _{0} \times 1.213\,\,\lambda _{0} \times 0.113\,\,\lambda _{0}$ </tex-math></inline-formula> , including the ground plane. The maximum measured impedance bandwidth of the single PSA was 23.1%. Furthermore, the measured maximum antenna gain was 11.5 dBi, whereas the same sized reference patch antenna showed only 6.3 dBi.

A Wideband Circularly Polarized Folded Reflectarray Antenna With Linearly Polarized Feed

The design and implementation of a wideband circularly polarized folded reflectarray antenna (CPFRA) with a linearly polarized (LP) feed antenna is presented in this letter. The subreflector of the proposed CPFRA is in the form of a polarization-sensitive frequency selective surface (FSS) based on the antenna-filter-antenna (AFA) technology other than the traditional polarizing grid. The AFA FSS is designed to convert the LP incident wave into circularly polarized (CP) wave within its passband and reflect the orthogonal LP incident wave over a wide frequency band. Futhermore, the sequential rotation technique is applied in the design of main reflectarray and subreflector to greatly enhance the axial ratio (AR) bandwidth of the CPFRA. An antenna prototype has been fabricated and measured at <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">X</i> -band. Good agreement between the measured and simulated results has been achieved by the wideband CPFRA. The measured results show that the maximum antenna gain reaches up to 28.2 dBic at 10.2 GHz with its aperture efficiency of 43.3%. The 3 dB gain frequency band is from 9.1 to 10.6 GHz and the 3 dB AR frequency band from 8.7 to 11.2 GHz, respectively.

A Wideband Circularly Polarized Complementary Antenna for Millimeter-Wave Applications

This work presents a design of an aperture-coupled complementary antenna for realizing circularly polarized (CP) broadside radiation at millimeter-wave (mm-wave) frequencies. The proposed antenna constructively combines a patch dipole (electric dipole radiation) and a folded loop antenna (magnetic dipole radiation), which are differentially excited by a longitudinal slot etched on the top layer of the substrate integrated waveguide (SIW). The combination of the proposed patch dipole and the folded loop antenna results in a paralleled electric dipole and magnetic dipole which can generate two orthogonal electric field components and 90° phase difference in the far-field radiation when they are in-phase excited. The proposed antenna achieves a wide impedance bandwidth of 46% from 48.47 to 77.46 GHz and a wide 3 dB axial ratio bandwidth (ARBW) of 47.3% from 51.64 to 83.61 GHz with an overlapped bandwidth of 40%. To further enhance the antenna gain, sequential rotation technique is adopted to construct a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2 \times 2$ </tex-math></inline-formula> subarray, which is further employed in a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4 \times 4$ </tex-math></inline-formula> subarray. The <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4 \times 4$ </tex-math></inline-formula> subarray is then used to construct an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8 \times 8$ </tex-math></inline-formula> antenna array, which achieves a wide impedance bandwidth of 33.8% from 56.11 to 78.95 GHz and a wide 3 dB ARBW of 38.8% from 53.57 to 79.32 GHz, with a maximum antenna gain of around 25.2 dBic. The proposed antenna element and array design would be a competitive candidate for future wireless applications operating at mm-wave spectrum.

Thin Circularly Polarized Slot Array Antenna for High-Band UWB Applications

This paper presents a thin 2 × 2 circularly polarized slot array antenna that operates in the high-band ultra-wideband (UWB) system. The proposed antenna is composed of three parts: a top metal part that consists of an L-shaped slot structure, a dielectric substrate, and a bottom floating metal layer. The design model and characteristics of the antenna element and array antenna are investigated through simulation and measurement. Experimental results show that the maximum gain of the prototype array antenna is 6.94 dBi at 9.02 GHz. The antenna size is 29.2 mm × 31.7 mm, and its thickness is 1.636 mm. By using a slot antenna structure, a thin circularly polarized antenna (thickness: 1.636 mm) with high gain was demonstrated. The antenna characteristics qualify the antenna to be used in high-band UWB applications.

Compact EH0-Mode Microstrip Leaky-Wave Antenna With Enhanced Gain in Broadside

This article presents an EH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> -mode microstrip leaky-wave antenna (LWA) with enhanced gain in broadside by bidirectionally exciting the inductive-loaded EH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> -mode microstrip line (MSL). In this way, enhanced gain is successfully attained in broadside at the desired frequency. To theoretically investigate such an attractive property, an equivalent circuit model is first established to illustrate that the working frequency as well as the phase and leakage constants can be independently controlled by altering the shunt inductance and resistance, and further properly adjusting their quantities. Then, a row of shorting pins is appropriately loaded at one side of the MSL, so as to realize the inductive-loaded periodical leaky-wave structure for broadside radiation. After that, a more effective and practical transmission line model is derived to fully investigate the side pin-loaded MSL. Based on this transmission line model, an efficient method is proposed to design the working frequency and the values of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta /k_{0}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\alpha /k_{0}$ </tex-math></inline-formula> in a controllable way. Furthermore, a gain enhancement of such an LWA is carried out with resorting to the directivity and radiation efficiency, aiming to acquire the maximum antenna gain. In final, the proposed EH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> -mode LWA with broadside radiation is simulated, fabricated, and measured. Good agreement can be found between the simulated far-field radiation patterns and the tested ones, which both evidently indicate that a high-gain broadside radiation beam is indeed achieved at the desired frequency.

Design and Characterization of Modified Comb Patch Antennas

This work deals with the proposal of a novel type of microstrip antenna, called MCPA the modified comb patch antenna. The proposed antennas is composed of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n$ </tex-math></inline-formula> parallel conductors, fed by a common microstrip. A dedicated mathematical framework, based on the multiconductors transmission line formalism, is proposed for antenna analysis and design. The analytical model is numerically validated with full-wave simulations, resulting in a 5% error in the predicted resonant patch length. A numerical study of antenna matching, size, radiation performance is carried out. The matching increases as the number of conductors increases, whilst gain of comb antennas made of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n$ </tex-math></inline-formula> conductors are about half dB higher than the equivalent full patch counterpart. Then, an eighty conductors was realized and measured to assess the frequency response of the antenna, as well as its radiation performances. An error of 1% between the predicted and measured value resonance frequency was observed. A difference of about 0.67dB was found for the measured maximum antenna gain, with respect to the simulated one. The proposed antenna design is appealing for printed electronics and wearable, on-textile applications.

Design of 1*4 Microstrip Antenna Array on the Human Thigh with Gain Enhancement

In this paper, at first attempted to design and simulate a stacked circular microstrip patch antenna for high gain at frequency 2.45 GHz, to apply on the industrial, scientific, and medical (ISM) applications. The antenna needs to be minimized for the array mounted on the human thigh, which has high gain and pattern scan capability. The substrate with a high relative permittivity is used for the designed antenna to minimize the dimension of the antenna. A 1*4 array antenna is designed for mount on the human thigh. The amplitude and phase of each antenna are obtained using the maximum-gain theorem to achieve the maximum gain of this array antenna. The coaxial feed is used to achieve good impedance matching, low cross-polarization, and easy control of the amplitude and phase of the element. For designing this entire array antenna, three-dimensional electromagnetic field simulation software Ansoft HFSS based on the finite element method is applied. To experimentally verify the performance, a prototype of the array antenna is fabricated and measurement is performed. The realized gain of the designed array antenna at the resonant frequency is 11 dB. This array structure can be mounted on a human thigh, waist, or head for medical applications, depending on the specific radius.

NOMA with optimal transmit antenna selection scheme with self adaptive metaheuristic model

AbstractNonorthogonal multiple access (NOMA) constitutes a promising technique in the fifth‐generation (5G) mobile networks. On the transmitter side, the concurrent usage of multiple antennas needs an appropriate count of parallel Radio Frequency (RF) chains at the front end. Owing to this consequence, it maximizes the power consumption, cost, and system complexity along with maximization in the antenna count. In order to tackle these aforesaid problems, some researchers prefer the Transmit Antenna Selection (TAS) for modeling the transmitter structure simple. The best antenna is selected opportunistically by an efficient TAS technique from multiple antennas and deploys a single RF chain for transmission. In this paper, a novel approach for optimized antenna selection in overlay CR networks using NOMA and SM is proposed via the usage of optimization tactics. To choose the desired respective antenna, this paper introduces a new Mean and Median Fitness Centered Moth flame Optimization (MM‐FCMO), which is the modified Moth Flame Optimization (MFO) Algorithm, which taken the core objectives such as power consumption and Mean Square Error (MSE). The MSE and power consumption of the chosen antennas have to be lower for the system to attain maximum antenna gain with lower noise. Finally, to exhibit that the presented work is much significant than the traditional works, a comparative analysis is made in terms of error minimization and statistical evaluation.