Antenna Dimensions Research Articles

EBG-based slotted T-shaped antenna for sub-6 GHz 5G application

ABSTRACT This paper proposes the design of a T-shaped antenna that resonates at 3.6 GHz, suitable for 5G small-cell technology. An EBG structure consists of four unit cells, each comprising rectangular strips. The periodic structure is combined with the antenna design, and performance enhancement in terms of gain and impedance bandwidth is observed. The gain of the antenna without periodic structure is 3.78 dBi, whereas with periodic structure it is enhanced by 1.1 dB and is noted as 4.8 dBi. The antenna dimensions are 38 mm × 37 mm × 3 mm. Also, the measured impedance bandwidth of the antenna structure without periodic structure is 60 MHz. In contrast, the proposed prototype antenna backed with an EBG structure provides the measured impedance bandwidth of 80 MHz (3.49 GHz to 3.57 GHz).

Ka-band phased array antenna with waveguide power distributor

Known designs of Ka-band phased array antennas incorporate an optical feed or a radial waveguide feed. Significant disadvantage of an optical feed is microwave energy overflow through antenna aperture, which decreases aperture efficiency and increases a side lobe level. Optical feed requires additional space for feeding antenna location and increases overall antenna dimensions. The design of a phased array with a radial waveguide feed forces placement of the phase shifter control circuits outside the dimensions of the array and increases overall antenna dimensions. The purpose of the article is to design a Ka-band phased antenna array (PAA) with a waveguide feed with smallest overall dimensions and various aperture shapes. The manufactured prototype of PAA with a grid pitch of 6x6 mm and size of 300x40 mm showed acceptable results of the side lobe level, scanning sector ±45° and gain factor. Proposed Ka-band phased array antenna design allows one to construct the extremely compact radar of various types including airborne radars.

Feasibility assessment of guided resonance modes in high Q and resolution mm-wave metamaterial biosensor

The development of Epsilon-near-zero (ENZ) metamaterial connected to a microwave (mm-Wave) bio-sensor, which exhibits very high practical performance, ultrafast response, and high accuracy, has become critical and benchmark in the integrated on-chip devices known as lab on chip (LoC). In order to achieve high efficiencies in perfect absorber based on harnessing the input mm-waves, a simple slot-antenna-based configuration is introduced, which involves efficient dielectric-metal-dielectric (DMD) configuration containing guided mode resonances and plasmonic induced transparency (PIT). By capitalizing on the simple configuration DMD and two slots antenna consisting of two bright modes and strong interaction between them, a new type of optical sensor is generated, which is extremely effective in harnessing input electromagnetic waves. Our research not only focuses on the design and fabrication of a mm-wave bio-sensor based on double-PIT (D-PIT) phenomena using ENZ metamaterial, but also explores the feasibility assessment of non-invasive application in order to achieve the biological materials of the human body, including bad bacteria of the bowel. The novel D-PIT-based sensor has garnered significant attention due to its exceptional capabilities and innovation in various practical optical sensing fields, particularly in the detection of biological materials. By tuning the dimensions of the slots antenna, we are able to achieve the first and second bright modes and static tunability of the proposed metamaterial sensor. Furthermore, the interaction between surface plasmon polaritons (SPPs) and input light demonstrates transverse electrical (TE) surface modes, which are insensitive to external factors.

Design of Circular and Rectangular Patch Antennas Using Teflon and Rogers Substrates for 5G Applications at 25 GHz

This paper presents a comprehensive study on the design and performance evaluation of circular and rectangular microstrip patch antennas tailored for 5G applications, operating at 25 GHz. Utilizing Teflon and Rogers substrates with superior dielectric properties, the antennas are meticulously crafted and rigorously analyzed. The study explores the design methodology, and simulation outcomes, and compares circular and rectangular patch antennas, focusing on their suitability for 5G systems. Through iterative simulations and optimizations, the antennas are fine-tuned to achieve optimal performance parameters, including impedance matching, radiation efficiency, and bandwidth, ensuring their efficacy in high-frequency communication environments. The design methodology involves precise calculations for optimal antenna dimensions, considering substrate material properties, dielectric constants, and desired radiation characteristics. Performance metrics such as peak directivity, gain, efficiency, and bandwidth are comprehensively evaluated and compared for both Teflon and Rogers substrates. This investigation contributes to advancing microstrip patch antenna design for 5G, elucidating the interplay between substrate materials, antenna geometries, and performance characteristics. The findings not only enhance our understanding of antenna design principles but also lay the groundwork for further optimization and refinement of microstrip patch antennas for future high-frequency communication systems.

AN ASYMMETRICAL PSI-SHAPED MULTIBAND ANTENNA FOR WIRELESS APPLICATIONS

In this article, a low-profile multiband asymmetrical psi-shaped antenna for different wireless applications is presented and analyzed. This multiband antenna consists of an asymmetrical psi-shaped radiator considered on a single layer FR4 substrate with compact dimensions. The better impedance matching characteristics between the radiating element and the signal source are obtained by employing a slotted structure. The designed antenna operates at six different frequency bands of 1.8-2.03 GHz [GSM1800, personal communication systems (PCS)], 4.64-5.35 GHz [wireless local area network (WLAN)], 6.05-6.95 GHz (C-band), 7.92-8.59 GHz (military), 9.55-11.14 GHz [fixed satellite service (FSS)], and 11.57-12.29 GHz (DBS) while the S<sub>11 </sub>value is lower than -10 dB. The Ansoft HFSS 21 electromagnetic simulator is employed to optimize the antenna dimensions and study the antenna functionality at the six different frequency bands. The designed antenna exhibits higher gain at six frequency bands. The developed multiband antenna is prototyped, and test results are generated to validate its performance. The simulation results authenticate acceptable agreement with the measurement results. This antenna is a good choice for GSM1800, PCS, WLAN, C-band, FSS, and military defense applications.

Low-cost and precise automated re-design of antenna structures using interleaved geometry scaling and gradient-based optimization

Design of contemporary antennas is an intricate endeavor involving multiple stages, among others, tuning of geometry parameters. In particular, re-designing antennas to different operating frequencies, makes parametric optimization imperative to ensure the best achievable system performance. If the center frequency at the current design is distant from the target one, local tuning methods generally fail, whereas global algorithms (e.g., nature-inspired procedures) incur prohibitive computational expenses, especially when antenna evaluation is performed using full-wave electromagnetic (EM) analysis. In this paper, a novel technique involving automated decision-making has been developed, whose main objective is low-cost and precise re-design of antenna structures over wide ranges of operating frequencies. The employed methodology involves knowledge-based simultaneous scaling of antenna dimensions and gradient-based performance improvements. The two stages are automatically interleaved, and embedded into an iterative optimization procedure. The problem-specific knowledge allows for carrying out the scaling phase, in which fast relocation of the center frequency of the antenna is performed, based on a single EM analysis of the structure. The gradient-based tuning phase enhances the design quality with regard to the assumed objectives. The process defaults to local optimization after the antenna center frequency becomes sufficiently close to the target. The main novelty of the proposed algorithm consists in development of an automated knowledge-based framework of quasi-global search capabilities linking brute-force scaling and design refinement. Our technique has been demonstrated with the use of three microstrip antennas, optimized for best matching and maximum in-band gain. The main findings are that for all structures, satisfactory designs have been identified despite poor starting points, with operating frequencies being away from the assumed targets. At the same time, the computational cost is comparable to conventional local search. The proposed approach is versatile, simple to implement and easy to handle, in particular, its control parameters do not require tailoring to a specific antenna structure at hand.

A miniaturized aperture‐coupled 4 × 4 MIMO array SIW antenna at K band

AbstractA planar miniaturized rectangular substrate integrated waveguide (SIW) cavity resonator with an array of patches is presented, which enhances the overall gain of antenna at the K band. The aperture‐coupled feeding is provided from SIW rectangular cavity resonator to reduce radiation losses as in microstrip feeding at a higher frequency. The resonating fields from the cavity excite an array of patches on the substrate. This is further replicated uniformly to design a 4 × 4 element multiple input multiple output (MIMO) antenna. The overall antenna dimension is 2λ × 3.1λ × 0.07λ, where λ is the operating wavelength. The compact structure configuration provides a high peak gain of 13.98 dBi resonating at 19.97 GHz in a broadside direction. An isolation of −17.53 dB is achieved by inserting metal pins. The envelope correlation coefficient of 0.0001 and total active reflection coefficient of −10 dB show characteristics of a high‐performing MIMO antenna. The antenna structure is simulated using HFSS ver. 2022, measured using Anritsu Vector Network Analyzer and Anechoic Chamber, the simulated and measured results are in good concurrence. The antenna is suitable for satellite communication, short‐range wireless applications in IoT, and radar.

Frequency-reconfigurable variode enabled metasurface reflector loaded antenna

A compact high gain frequency reconfigurable metasurface reflector (MSR) loaded antenna using a varactor diode is proposed in this paper. In comparison to a traditional antenna, a metamaterial (MTM) loaded with CSRR is used to achieve a size reduction up to 70%. The ground plane of the proposed slotted decagon antenna has been loaded with a complementary split-ring resonator (CSRR). With dimensions of 0.24 λ × 0.24 λ × 0.013 λ (λ represents the center frequency at 2.40 GHz) the antenna is extremely compact. The antenna is designed on an FR4 substrate with εr = 4.4 & 1.6 mm of thickness. The investigation shows that utilization of the MSR structure has significantly increased gain compared to the decagon antenna without MSR. The MSR-loaded antenna dimension is 0.48 λ × 0.47λ × 0.013 λ (λ represents the center frequency at 2.40 GHz). Frequency reconfigurability is introduced by placing a varactor diode on the patch’s upper side. Changing the varactor’s DC reverse bias voltage from 0 to 10 V causes its resonance frequency to shift from 2420 to 2550 MHz, giving it a tuning ratio of 1.35. The proposed antenna offers efficiency ranges from 70%–80% over the operating bands. Except for a small deviation, there is a fair match between measured and simulated values. The antenna can be used in a variety of current and future communication systems.

Design and Optimization of a Compact Super-Wideband MIMO Antenna with High Isolation and Gain for 5G Applications

This paper presents a super-wideband multiple-input multiple-output (SWB MIMO) antenna with low profile, low mutual coupling, high gain, and compact size for microwave and millimeter-wave (mm-wave) fifth-generation (5G) applications. A single antenna is a simple elliptical-square shape with a small physical size of 20 × 20 × 0.787 mm3. The combination of both square and elliptical shapes results in an exceptionally broad impedance bandwidth spanning from 3.4 to 70 GHz. Antenna dimensions are optimized using the trust-region algorithm to enhance its impedance bandwidth and maintain the gain within a predefined limit across the entire band. For that purpose, regularized merit function is defined, which permits to control both the single antenna reflection response and gain. Subsequently, the SWB MIMO system is constructed with four radiators arranged orthogonally. This arrangement results in high isolation, better than 20 dB, over a frequency band from 3.4 to 70 GHz band. Further, the system achieves an average gain of approximately 7 dB below 45 GHz and a maximum gain equal to 12 dB for 70 GHz. The system exhibits excellent diversity performance throughout the entire bandwidth, as evidenced by the low envelope correlation coefficient (ECC) (<3 × 10−3), total active reflection coefficient (TARC) (≤−10 dB), and channel capacity loss (CCL) (<0.3 bit/s/Hz) metrics, as well as the high diversity gain (DG) of approximately 10 dB. Experimental validation of the developed SWB MIMO demonstrates a good matching between the measurements and simulations.

Hexagonal Microstrip Patch Antenna with Defective Ground Structure for Wideband Applications

The complexity and variety of modern wireless communication devices have resulted in an increase in the need for high-performance and wideband antennas. This research proposes an innovative approach for enhancing the bandwidth of hexagonal patch antennas using a microstrip line feed and the Defected Ground Structure (DGS) technology. The area of the hexagonal patch with defective ground structure wideband antenna is 32×24 mm2. The wideband ability and compact dimensions of the hexagonal patch antenna make it attractive. The DGS approach is used to change the resonant behavior of the antenna, resulting in a significant bandwidth enhancement. The simulation results demonstrate that combining DGS with the microstrip feed leads to significant enhancements in gain, radiation characteristics, and impedance bandwidth. The approach has potential for a range of wireless communication applications that demand wide performance in a compact antenna design.

Dual band antenna in licensed and unlicensed frequency bands based on superformula for 5G applications

In this paper, the design and analysis of dual bands antenna is carried out. The ranges of frequencies are below 6 GHz and above 24 GHz. The superformula was used to design the proposed antenna where the curve profile of the proposed antenna is obtained by adjusting the six different parameters of the super-formula. The antenna shape likes the sunflower was mounted on flame retardant level 4 (FR4) substrate of dimensions of 32×32×1.5 mm3 and fed by a microstrip. The antenna is simulated using a computer simulation technology (CST) simulator. Results of the simulation showed that the antenna works in the licensed band (5.5–5.8 GHz) and the unlicensed band (24-40) GHz with voltage standing wave ratio (VSWR) less than 2 and return loss below -10 dBm. Also, the proposed design showed better performance than the normal ellipse-based antenna design with the same antenna dimensions.

High Performance Antenna System in MIMO Configuration for 5G Wireless Communications Over Sub‐6 GHz Spectrum

AbstractThis paper presents a high‐performance multiple input and multiple output (MIMO) antenna comprising 2 × 2 configuration of radiating elements that is designed for sub‐6 GHz applications. The proposed MIMO antenna employs four identical radiating elements. High isolation between the radiating elements and therefore reduced mutual coupling is achieved by spatially arranging the radiating elements in an orthogonal configuration. Also, a novel frequency selective surface (FSS) was employed to increase the gain of the MIMO antenna over a wide bandwidth from 3 to 6 GHz. This was achieved by locating the FSS above the antenna at a certain height. The FSS essentially enhanced the antenna's directivity, reduced back lobe radiation and mutual coupling. The antenna was fabricated on a standard Rogers RT Duroid 5880 dielectric substrate with a 0.8 mm thickness. The overall dimension of the MIMO antenna is 50 × 50 × 12.5 mm3 and it operates from 3.8 to 6 GHz, which corresponds to a fractional bandwidth of 41%. The proposed MIMO antenna has a measured peak gain of 4.8 dBi and inter radiation element isolation >20 dB. Its envelope correlation coefficient is <0.1 and diversity gain >9.9 (dB). These characteristics make the proposed MIMO antenna system suitable for 5G communication systems.

Design of Domino-Resonators for Enhanced Power and Data Transmission of 13.56 MHz RFID Sensors

This paper presents a straightforward design algorithm to enhance power and data transmission for 13.56 MHz Radio Frequency Identification (RFID) sensor applications by using domino-resonators. In this algorithm, the transformed transponder impedance and modulation depth seen at the reader antenna are formulated and modeled under the presence of domino-resonators. To improve the accuracy, voltage-clamped mode of the tag Integrated Circuit (IC) is considered, which enables accurate calculation of the maximum readable distance, transferred power and equivalent tag IC impedance. For the sake of simplicity, a type-A ultralight tag IC is used and modeled, while all resonators and tag antenna dimensions are based on standard smart-card sized coils. The design algorithm is coded in MATLAB for a 5-coil RFID system, i.e. with three identical domino-resonators, and verified using LT-Spice simulations. For experimental validation, the designed 5-coil RFID system is implemented for enhancing the distance between a commercial 13.56 MHz RFID reader and ISO/IEC 14443A standard RFID tag IC.

Novel Frequency-Reconfigurable Antennas with Ring Resonators and RF Switches: Enhancing Versatility and Adaptability in Wireless Communication Systems

This study introduces innovative designs for frequency-reconfigurable antennas that utilize ring resonators combined with either PIN diodes or RF switches. These designs enhance the versatility, adaptability, and overall performance of the antennas in wireless communication systems. By controlling the switches and ring resonator, the antenna’s resonant frequencies and bandwidths can be adjusted, allowing for compatibility with various communication standards and frequency ranges. The proposed antenna exhibits four distinct operational states, each characterized by different resonance frequencies and operating frequency bands. Return loss, radiation pattern, radiation efficiency, and surface current distribution are analyzed for each state. State-1 (ON-ON) and State-2 (OFF-ON), which are characterized by resonance frequencies of 2.4 GHz and 3.33 GHz respectively, offer ranges suitable for Wi-Fi, Bluetooth, ISM, and IoT applications. State-3 (ON-OFF), with a resonance frequency of 3.0 GHz and bandwidth spanning from 2.59 GHz to 3.643 GHz, complies with Wi-Fi, Wi-Fi 6, and IoT requirements. State-4 (OFF-OFF) covers the band centered around 3.45 GHz. It is compatible with many applications such as 5G mid-band, Wi-Fi 6E, IoT, and cellular systems. The proposed antenna designs are versatile and compact since the overall antenna dimensions are 25 × 18 × 1.6 mm3. The radiation efficiency of the antenna configuration varies depending on operational states. By utilizing the advantages of both ring resonators and RF switches, the proposed antenna configurations offer new solutions that enhance their performance in wireless communication systems. This study compares the effects of using PIN diodes and SPDT switches on the performance of antennas and also examines the DC biasing effect on antenna characteristics. The simulation results are validated by the experimental analysis. The proposed antenna designs offer a new approach for wireless communication systems by using both ring resonators and RF switches.

A Single Plane Low profile Patch Antenna π-Shaped Slots and Low Side Lobe Level for Directive Wireless Communications

The patch antenna was used recently for ISM band (5.725 – 5.875) GHz, the patch antenna suffers of being an antenna with low gain as well as narrow operating bandwidth with high side lobe level (SSL) radiation pattern. A single plane with low profile and easy fabrication microstrip patch antenna has been proposed in this work was presented for directive communications and operates in Industrial, Scientific, and Medical (ISM) band 5.8 GHz with low SLL radiation pattern and gain of 5.20 dB for pint to point (directive). The gain of antenna has been increased while SLL decreased due to shifting the radiating patch and feeder of antenna with specific distance toward –ve side of the X-axis without any need for using techniques which would increase overall dimensions of antenna. The antenna has been printed on Arlon AD 250 substrate. The simulated results of antenna’s gain, operating frequency, bandwidth, return loss, and radiation pattern are presented. CST Microwave studio software was used in this design simulation.

Quasi-Yagi antenna design for LTE applications and prediction of gain and directivity using machine learning approaches

In recent years, improvements in wireless communication have led to the development of microstrip or patch antennas. The article discusses using simulation, measurement, an RLC equivalent circuit model, and machine learning to assess antenna performance. The antenna's dimensions are 1.01 λ0×0.612λ0 with respect to the lowest operating frequency, the maximum achieved gain is 6.76 dB, the maximum directivity is 8.21 dBi, and the maximum efficiency is 83.05%. The prototype's measured return loss is compared to CST and ADS simulations. The prediction of gain and directivity of the antenna is determined using a different supervised regression machine learning (ML) method. The performance of ML models is measured by the variance score, R square, mean square error (MSE), mean absolute error (MAE), root mean square error (RMSE), and mean squared logarithmic error (MSLE), etc. With errors of less than unity and an accuracy of roughly 98%, Ridge regression gain prediction outperforms the other seven ML models. Gaussian process regression is the best method for predicting directivity. Finally, modeling results from CST and ADS, as well as measured and anticipated results from machine learning, reveal that the suggested antenna is a good candidate for LTE.

High gain metasurface integrated millimeter-wave planar antenna

Abstract A metasurface reflector-backed wideband planar antenna is designed for millimeter-wave (mmWave) applications. A simple meandering structure is used for radiation element design, while the back side consists of a partial ground plane and parasitic elements. The utilization of meander-shaped element led to small antenna dimensions. The partial ground plane is used to achieve wide bandwidth, while the parasitic elements are used to improve the impedance matching toward higher frequency bands. To achieve high gain and directional radiation characteristics, an array of metasurfaces is placed behind the radiating element. It is observed from the simulated results that the proposed antenna system offers 17.72 GHz of impedance bandwidth in the operating range of 22.28–40 GHz, while the measured impedance bandwidth is noted to be 15.8 GHz, ranging from 23 to 38.8 GHz. Furthermore, it is observed that a metasurface-based planar antenna tends to achieve a peak gain of ≈9 dBi in the band of interest.

A low‐profile dual‐wideband magnetoelectric dipole antenna with stable gain

AbstractA dual‐wideband magnetoelectric dipole antenna is proposed. The magnetoelectric dipole is fed by a hook‐shaped metal sheet. To increase the gain at the upper band, the radiation arm of the electric dipole is designed in stepped shape. To widen the impedance bandwidth of the lower band, stepped‐shaped metal walls are employed and placed along the edges of the ground plane. To further improve and stabilize the higher band gain, four parasitic umbrella‐shaped metals are utilized. By using this novel scheme, a magnetoelectric dipole antenna with dual‐wideband operation is designed. It introduces two wide bandwidths of 35.3% (0.698–1 GHz) for the lower band and 63% (1.52–2.9 GHz) for the upper band. The lower‐band gain is stabilized within 7.3 ± 0.6 dBi, while the upper‐band gain is stabilized within 9.2 ± 0.8 dBi. The antenna dimension is only 0.41λL × 0.41λL × 0.1λL (λL denotes the wavelength at 0.698 GHz in vacuum).

Effects of the Geometrical Dimensions of Applicator Antennas for Microwave Radiothermometry on Radiobrightness Temperature Measurement Results

Effects of the Geometrical Dimensions of Applicator Antennas for Microwave Radiothermometry on Radiobrightness Temperature Measurement Results

Design of a Dual-Band WiFi Antenna Using the Theory of Characteristic Modes and Nested Chinese Characters

In this paper, a dual-band WiFi antenna and its Multiple Input Multiple Output (MIMO) system application is designed, fabricated, and measured based on the Chinese characters “Men” and “Wei”. The antenna uses a 40 × 40 × 1.6 mm3 FR4 substrate to analyze the combinatorial structure of Chinese characters using the theory of characteristic modes, to optimize the antenna dimensions by analyzing the mode current distribution, and to broaden the antenna bandwidth by etching rectangular slots on the ground. The measured and simulated results show that the four-element MIMO antenna covers 5.68–8.01 GHz, the isolation between the antennas is higher than 20 dB in the working band, the envelope correlation coefficient and the channel capacity losses of the simulation are lower than 0.001 and 0.18 bits/s/HZ, respectively. The efficiency of the antenna is higher than 90%, and it can be used for WiFi communication bands (5.8 GHz and 6 GHz).