Designed Antenna Structure Research Articles

Circularly polarized implantable MIMO antenna for skin, brain and heart implantation with wide axial ratio bandwidth

SummaryA unique MIMO antenna with circular polarization characteristics that works similarly for skin, brain and heart phantoms has been proposed in this paper. The twin rectangular X‐shaped slot that serves as the basic structure of the proposed antenna is entirely planar and low‐profile but has a defective ground plane. For three different phantoms, the proposed antenna resonates at 2.4–2.45 GHz ISM band. With a dimension of , the antenna exhibits compactness. Rogers RT/duroid 6010 substrate material has been used to fabricate the antenna in order to validate the designed antenna structure. Utilizing the high dielectric material for both substrate and superstrate, both skin‐mimicking gel and minced hog meat were employed in the experiment setup at 2.45 GHz ISM band. At ISM band, −28.3 dBi has been observed has realized peak gain. The obtained fractional bandwidth (FBW) and Axial Ratio Bandwidth (ARBW) values are 30.67% and 45%, respectively. Also, the maximum specific absorption rate (SAR) values are found to be in the acceptable limit regulated by IEEE.

Non-conventional leather substrate based high isolation wideband MIMO antenna for body-centric applications

This work presents the design of a dual-port high isolation compact wideband wearable multiple-input multiple-output (MIMO) antenna employing a non-conventional leather substrate material. The designed antenna structure comprises defected structure at the ground plane, including two semicircular slots and two 'H' shaped stubs in the cascaded form to minimize the coupling effect between the antenna ports. The antenna works over the 2.22–8 GHz frequency range with a fractional bandwidth of 113.12 %, covering the application bands of WLAN (2.4–2.484 GHz), WiMAX (3.2–3.85 GHz), WLAN (5.15–5.35 GHz/5.725–5.825 GHz), C band downlink/uplink (3.7–4.2 GHz/5.925–6.425 GHz) and downlink defense (7.2–7.7 GHz) band. The suggested antenna provides port isolation above 27 dB, envelope correlation coefficient (ECC) under 0.09, diversity gain (DG) above 9.94 dB, channel capacity loss below 0.33 Bits/Sec/Hz, low magnitude ratio between mean effective gains of two ports (<0.1 dB), and a stable total active reflection (TARC) over the active spectral region. The designed antenna offers a SAR value less than the threshold level (<1.6 W/kg). The constructed MIMO antenna structure consumes a volume of 32 × 52 × 2 mm3.

A metal hybrid bistable composite tube for multifunctional and reconfigurable antenna

The bistable composite is a deformable lightweight structure with two stable states, which are widely used in aerospace and space fields as deployment mechanisms and deformable structures. In this paper, a new application is proposed as an omnidirectional and directional radiation reconfigurable antenna based on a bistable composite tube. The antenna is prepared based on carbon fiber composite (CFRP) and glass fiber composite (GFRP) as the substrate and metal as the antenna layer co-cured. Mechanical behavior and material micro-interface analyses of the bistable structures are performed. Antennas of different materials and different layups are fabricated and analyzed. The results indicate that the designed antenna structure can be stabilized in the unfolded or stowed state without external support, unfolded into an omnidirectional antenna, and stowed into a directional antenna. The electromagnetic analysis is simulated and experimented to verify its performance as a multifunctional and reconfigurable antenna. Meanwhile, this bistable antenna possesses many advantages, including its lightweight, high storage ratio, and rapid reconfiguration, which make it an excellent candidate for satellite and spacecraft antennas.

Investigation of Origami Inspired Sub-6 GHz Accordion Monopole Antenna for 5G Applications

This study presents an origami inspired sub-6 GHz accordion monopole antenna for 5G applications. Parametric study is performed by varying monopole height, fold width and bevel angle to examine the antenna performance in the 1 GHz - 6 GHz frequency range. The proposed antenna is designed with the values that yield the best performance in accordance with the results of parametric study. Antenna behavior is then evaluated in terms of Return Loss, gain and radiation pattern. The proposed antenna operates in 1.22 GHz - 6 GHz frequency range which covers almost the entire sub-6 GHz range with an approximate impedance bandwidth of 132%. Hence, the designed antenna structure has a good performance in the sub-6 GHz and it is a promising design for 5G applications.

Wideband slot antenna gain enhancement using metasurface reflector

Wideband slot antenna gain enhancement using concentric square and circular loop metasurface reflector (SCLMR) is presented in this paper. In two steps, the design is realized. The analysis design of a FSS-based SCLMR unit cell is included in the first step. The SCLMR structure is made up of resonant metallic square-loop and inner circular loop structures. In terms of bandwidth, the unit cell structure can be considered as a stop-band filter (2.5 GHz-6.5 GHz). The design of a wideband slot antenna (29 mm × 24 mm × 1.57 mm) is included in the second step. EM simulation tool is used to analyze, design, optimize, and validate the proposed unit cell and slot antenna combination. CST microwave studio is utilized to design and analyze a slot antenna and a unit cell in this study. The computed result of an antenna with SCLMR indicates a 101.21 % operational impedance bandwidth (2.76 GHz to 8.41 GHz). With SCLMR, the antenna has a high gain of 8.75 dBi. The designed antenna structure provides a gain enhancement of 5.50 dBi while in comparison to the same antenna without SCLMR.

Dimension optimization of multi-band microstrip antennas using deep learning methods

The electromagnetic frequency spectrum is divided into different sub-frequency bands. These sub-frequency bands are allocated for different applications. In these days, devices operating in multiple sub-frequency bands provide significant advantages. Devices require antenna structures to operate in multiple frequency bands. Microstrip antennas have become prominent antenna structures with their small size, portable structures and easy integration into other systems. In this study, microstrip antenna structure which can work in multi frequency bands is designed. At the same time, it was used with deep learning methods in optimization of antenna sizes to ensure the optimization of the designed antenna in a shorter time. The operating frequencies of designed antenna structure work in the C and X band as seen in the obtained results. According to IEEE standards, C band is determined between 4 GHz and 8 GHz; X band determined as in 8 GHz and 12 GHz frequency range. In the proposed antenna structure, the ability to operate in multi-band structures was achieved by means of a C-shaped antenna array. In the deep learning methods that will be used in the optimization process, five different Long Short Term Memory (LSTM) models are used. The most important advantage of deep learning methods is that it can achieve satisfactory results by identifying the necessary features for solving difficult and time consuming problems with its own learning ability. In this context, 52 pieces of antenna data were produced. 40 pieces of data were used in the training process and 12 pieces of data were used in the test stage. The lowest root mean square error (RMSE) performance obtained in the test data was determined as LSTM-1 + Dropout layer-1 + LSTM -2 + Dropout layer-2 and 1.0161 error value. The obtained results by proposed method were evaluated in High Frequency Simulation Software (HFSS) program. In experimental results, it was observed that the results produced by the deep learning model and the test data were very close to each other.

Synthesis of Goblet shape defected ground slotted microstrip patch antenna

This paper presented for investigation, how the defects as well as slots of different shapes and sizes on the ground of microstrip patch antenna (MPA) improve its characteristics like VSWR, Return Loss, efficiency, etc. This has been done by cutting a rectangular shape of defect on the ground and cut a slot on the goblet shaped patch of designed antenna structure. This microstrip antenna is suitable for tracking data, satellite communication, etc. The performance and advantages of microstrip antenna such as low cost, low profile, low weight made them the perfect choice for communication systems. In the proposed defected ground microstrip patch antenna (DG - MP A), a rectangular slot (1.25mm × 3.75mm) is cut on the Goblet Patch (10.71mm ×41. 5mm ×1. 5mm) of the structure. An inset feed (-11mm x 6mm) is introduced in this microstrip antenna. The antenna designed to function at 2.2 GHz. The proposed antenna not only operate at 2.2 GHz frequency, but also offers Return loss -26.86, VSWR 0.78, with frequency 12.85 GHz (Ku - band).

Hybrid Precoding Design for Wideband THz Massive MIMO-OFDM Systems With Beam Squint

The terahertz (THz) communication has been considered as a promising technique for future 6G wireless networks because of its tens of GHz bandwidth. However, the path direction for THz channel under different subcarrier frequencies is different (i.e., beam squint), which leads to the serious beam gain loss for conventional hybrid precoding design schemes. Thus, the effect of beam squint must be considered for the application of the wideband THz systems. In this paper, we consider the precoding design problem in a wideband THz massive multiple-input-multiple-output (mMIMO) orthogonal frequency division multiplexing (OFDM) systems with beam squint. We first design two new sparse radio frequency chain antenna structures, including fully connected and subarray. Based on the designed structure, we formulate an average rate maximization problem by jointly designing the hybrid analog/digital precoding at the transmitter and analog combine vector at the receiver. Since it is a challenge to optimize the precoding simultaneously, we propose an alternatively iterative algorithm to solve it under each antenna structure. Finally, the simulation results are conducted to show the effectiveness of the designed antenna structure and proposed precoding schemes.

Design of a meandered line microstrip antenna with a slotted ground plane for RFID applications

In this article, the design and analysis of a meandered line monopole antenna with a defected ground structure (DGS) for RFID applications are investigated. In the proposed antenna, the linearly polarized meandered line acts as the main radiator whereas the inverted C-shaped patch acts as a parasitic element. The defects on the ground plane are responsible for providing low pass filter performance. From the measurement, it is found that the antenna operates over the frequency range of 5.74 GHz–6 GHz with a resonating frequency at 5.82 GHz. The designed antenna structure shows omnidirectional radiation characteristics with the realized gain value greater than 4 dBi in the entire operating frequency range. It has an overall dimension of 0.55λ0 × 0.55λ0 × 0.03λ0 at resonating frequency which is effectively fit for use in RFID readers operating at 5.82 GHz ISM band.

A Dielectric Resonator Antenna with Enhanced Gain and Bandwidth for 5G Applications.

In this paper, a dielectric resonator antenna (DRA) with high gain and wide impedance bandwidth for fifth-generation (5G) wireless communication applications is proposed. The dielectric resonator antenna is designed to operate at higher-order mode to achieve high antenna gain, while a hollow cylinder at the center of the DRA is introduced to improve bandwidth by reducing the quality factor. The DRA is excited by a microstrip line with a narrow aperture slot. The reflection coefficient, antenna gain, and radiation pattern of the proposed DRAs are analyzed using the commercially available full-wave electromagnetic simulation tool CST Microwave Studio (CST MWS). In order to verify the simulation results, the proposed antenna structures were fabricated and experimentally validated. Measured results of the fabricated prototypes show a 10-dB return loss impedance bandwidth of 10.7% (14.3–15.9GHz) and 16.1% (14.1–16.5 GHz) for DRA1 and DRA2, respectively, at the operating frequency of 15 GHz. The results show that the designed antenna structure can be used in the Internet of things (IoT) for device-to-device (D2D) communication in 5G systems.

A miniaturized printed monopole antenna loaded with hexagonal complementary split ring resonators for multiband operations

A miniaturized multiband printed monopole antenna is reported using hexagonal complementary split ring resonator (HCSRR) slots. Antenna miniaturization and multiband are accomplished by employing metamaterial inspired structure HCSRR. The proposed antenna consists of three HCSRR slots, it makes the antenna to resonate at 1.62 GHz, 2.4 GHz, 3.3 GHz, and 5.8 GHz frequency bands. The designed antenna structure has a small size of 20 20 1.6 mm3, which is fabricated on an FR-4 substrate with dielectric constant of 4.4. The pass band characteristics of HCSRR are examined in detail for acquiring multiband abilities of the compact antenna, which is evaluated by use of the precise LC equivalent circuit design equations. The metamaterial property of the HCSRR is also studied to validate the resonance frequencies of the proposed antenna. Simulated and tested data are investigated. The prototype antenna has adequate advantages, with a simple structure, compact size, multiband, and uniform radiation patterns.

A new monopole antenna in the form of double dollar-symbol for WLAN (5.1- 6 GHz) applications

In this paper, we present a new monopole antenna design for WLAN (5.1-6 GHz) application. The proposed antenna fed by a microstrip and the radiating element is in the form of a double dolar-symbole. The antenna designed is printed on a partial ground plane, and the resulting antenna has been found to possess a compact size of 20 mm × 20 mm, and covers specific bands from the frequency spectra.A parametrical study is performed to optimize the geometry of the antenna structure and a comparison study also will be presented for different kind of ground plane material. The designed antenna structure is simulated using the High Frequency Structural Simulator (HFSS).

Implementation of Microstrip Patch Antenna for Wi-Fi Applications

In recent years, the inventions in communication systems require the design of low cost, minimal weight, compact and low profile antennas which are capable of main-taining high performance. This research covers the study of basics and fundamentals of the microstrip patch antenna. The aim of this work is to design the microstrip patch antenna for Wi-Fi applications which operates at 2.4 GHz. The simulation of the proposed antenna was done with the aid of the computer simulation technology (CST) microwave studio student version 2017. The substrate used for the proposed antenna is the flame resistant four (FR-4) with a dielectric constant of 4.4 and a loss tangent of 0.025. The proposed MSA is fed by the coaxial probe. The proposed antenna may find applications in wireless local area network (Wi-Fi) and Bluetooth technology. And the work is the design of a Hexagonal shaped microstrip patch antenna which is presented for the wireless communication applications such as Wi-Fi in S-band. The designed microstrip patch antenna consists of a hexagonal patch which is found to be resonant at the frequency of 2.397 GHz with the return loss of -31.2118 dB having satisfactory radiation properties. The proposed antenna is the compact design of 28.2842mm 48.2842mm area on the FR4-epoxy substrate with dielectric constant of 4.4 and thickness of 1.6. The designed antenna has the realized gain of 3.42 dB at the resonant frequency of 2.397 GHz. After simulating with the CST software, the patch antenna was fabricated using the MITS milling machine on the FR-4 substrate in the YTU’s communication lab. The fabricated antenna was measured by the Vector Network Analyzer. Then, the simulation and measurement results were compared. The designed antenna structure is planar, simple and compact since it can be easily embedded for Wi-Fi applications, cellular phones and wireless communications for low manufacturing cost.

S-대역 4×1 광대역 위상배열안테나에 관한 연구

In this work, an aperture-coupled patch array antenna with wideband characteristics was designed and arrayed in a 4×1 S-band. The designed antenna structure consists of two layers, and it possesses wideband characteristics achieved using coupling between the two layers. The first layer is comprised of four radiation patches and the second layer has an aperture and a ground plane. The antenna structure possesses 15 % wideband characteristics and the center frequency is at 3.2 GHz. A phase shifter was added to the array antenna to enable beam steering. The proposed phase array antenna was fabricated and measured. Our proposed design enables beam steering up to 35°.

Tri-band composite cylindrical dielectric resonator antenna with hybrid mode excitation and cross-polarization suppression

This communication investigates composite cylindrical dielectric resonator antenna (CDRA) for various wireless applications. Three important features of proposed antenna design are (i) realization of two different hybrid modes, that is, HEM11δ and HEM12δ mode in CDRA with the help of modified annular ring printed line (work as both magnetic dipole and electric dipole), both the hybrid modes support broadside radiation characteristics (ii) suppression of HEM21δ mode, in order to reduce the cross-polarization level in H-plane of other hybrid modes (HEM11δ and HEM12δ mode) by an amount of 8-10 dB (iii) creation of triple-band attribute using the concept of composite antenna. The proposed antenna design has been fabricated and practically tested. Simulated outcomes show good agreement with measured outcomes. It works in three frequency bands, that is, 2.25-2.79 GHz, 3.1-4.0 GHz, and 5.05-5.6 GHz. The designed antenna structure is appropriate for WLAN and WiMAX applications.

Asymmetrically CPW-fed ladder-shaped fractal antenna for UWB applications

A compact asymmetrically CPW-fed ladder- shaped UWB fractal antenna is presented. An impedance bandwidth of 4.56---13.1 GHz is achieved by using four iterations of H-shaped radiating element, modified feed line, asymmetrical feeding and slot loaded ground plane. Omnidirectional radiation patterns are achieved in H-plane at all frequency points in the operating frequency band. The bidirectional nature of E-plane patterns at lower frequencies is observed to be shifted to directional nature at higher frequencies. The designed antenna structure has an average gain of 2.84 dB with a constant group delay. The designed antenna structure is analyzed for three different substrate materials i.e. CNT, Ni0.2Co0.2Zn0.6Fe2O4 and FR-4 epoxy. A good agreement is achieved between the simulated and measured results. This antenna structure has advantages of wider bandwidth and smaller dimensions over already reported ones.

Asymmetrically fed octagonal Sierpinski band-notched super-wideband antenna

A compact microstrip-line-fed octagonal Sierpinski band-notched super-wideband (SWB) fractal antenna is presented. It comprises an asymmetrical feedline and rectangular ground plane loaded with a single rectangular notch. An impedance bandwidth of 3.87---35 GHz with band rejection for 7.24---11.11 GHz is achieved by using the second iteration of an octagonal Sierpinski radiator geometry. The band rejection function is an inherit property of the designed antenna geometry. The designed antenna has a footprint of $$25\times 19\hbox { mm}^{2}$$25×19mm2. In the notched band, a high ($$\ge 4$$?4) voltage standing wave ratio (VSWR) is observed. Stable radiation patterns are achieved in the operating bands. The designed antenna structure has advantages of wide bandwidth and miniaturized dimensions compared with other SWB antenna structures, along with its band-notch characteristic.

Elliptical Annular Slot Loaded Trapezoidal Dipole Antenna for Band-Notched UWB Applications

In this paper, a semi-elliptical annular slot loaded trapezoidal dipole antenna with band-notched characteristics for UWB applications is designed. A microstrip feedline consisting of multiple feedline sections is used for improving the impedance matching. The band-notched characteristics for WLAN band are achieved by loading the trapezoidal dipole arms with semi-elliptical annular slots. The designed antenna structure has an operating range from 3.5-12.4 GHz(109%) with band-rejection in the frequency range of 5-6 GHz. Nearly omnidirectional patterns are achieved for the designed antenna structure. The designed antenna structure provided an average peak gain of 2.12 dB over the entire frequency range except in the notched band where it reduced to -2.4 dB. The experimental and simulation results are observed to be in good agreement. An improved bandwidth performance with miniaturized dimensions as compared to earlier reported antenna structures is achieved.

Asymmetrically CPW-fed octagonal sierpinski UWB fractal antenna

An asymmetrically CPW-fed octagonal Sierpinski fractal antenna is designed for ultrawideband applications. It comprises of a second iterative fractal radiating patch, microstrip feedline and asymmetrical coplanar waveguide ground planes. An impedance bandwidth of 3.73 GHz to more than 20 GHz is achieved. Stable radiation patterns and desirable gain characteristics are observed. The simulated and experimental results are found to be in good agreement. The designed antenna structure has advantages of wide bandwidth and miniaturized dimensions over already reported UWB antenna structures. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1738–1745, 2016

A compact metamaterial multiband antenna for WLAN/WiMAX/ITU band applications

In this paper, a compact metamaterial multiband antenna is proposed for wireless local area network (WLAN), worldwide interoperability for microwave access (WiMAX) and international telecommunication union (ITU) band applications using a modified Triangular Split Ring Resonator (TSRR). In this work, we designed a modified TSRR with metamaterial property to obtain desirable negative permeability bands that help in accommodating all three frequency bands of interest in a single device. This approach leads to the considerable reduction of the device structure. The overall dimension of the proposed antenna structure has a compact size of 25.7×23.2×1.6mm3 and covers specific bands from the frequency spectra of 2.4/5.2/5.8, 3.5, and 8.2GHz for WLAN, WiMAX, and ITU, respectively, with uniform radiation characteristics. The designed antenna structure is simulated using the High Frequency Structural Simulator (HFSS), and a prototype is developed and tested. The detailed analysis of the results obtained is presented. It is determined that the performance of the proposed antenna is superior to that of the existing antennas in the literature.