WLAN Band Research Articles

A Low-Profile Microstrip Vertically Polarized Endfire Antenna With 360° Beam-Scanning and High Beam-Shaping Capability

A novel low-profile vertically polarized planar endfire smart antenna that can achieve 360° beam-steering and high beam-shaping capability is proposed. The microstrip antenna is printed on a single thin substrate with a vertically polarized omnidirectional driven source and 36 tunable slot-integrated microstrip vertically polarized resonators (SMVR) for shaping the endfire beams. To verify the design approach, a prototype operating at the 5 GHz WLAN band is fabricated and tested. The results show that the antenna operates from 5.55 to 5.75 GHz and is capable of scanning a single endfire beam from 0° to 360° in the full azimuth plane. The scanning resolution and the maximum realized gain are 15° and 8.2 dBi, respectively. Moreover, multiple radiation pattern shapes including omnidirectional beam, dual-beams, and tri-beams can also be generated by the antenna. The overall antenna height is only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.06~\lambda $ </tex-math></inline-formula> at 5.6 GHz. This design provides a new antenna configuration for low-profile vertically polarized endfire beam-steering and beam-shaping antenna and is promising for future wireless communication systems with lost-cost beamforming property.

Studying and evaluation physical characteristic of composite substrate chip and, its application

We aim to demonstrate the creation of a fabricated fluidic antenna based on dielectric PDMS substrate, its unique properties of conductivity, flexibility, robustness, and use as an antenna. We evaluated an appropriate fluidic solution comprised of a polyethyleneimine (PEI) matrix assembled from nanoparticle Ttinum oxides and graphene. Various investigations of its mechanical flexibility (stress), thermal properties (DSC), and IR have been carried out on fabricated PDMS substrates, and a dielectric was recorded at 2.67. In addition, (TEM), IR, UV, and Electrochemical Impedance (EIS) tests have been performed to evaluate the PEI matrix-like surface morphology. The measurement and simulation outcomes show that the fabricated antenna operates at 1.8–2.6 GHz, which covers the WLAN band area.

Printed compact four-port wearable MIMO antennas for wideband wireless applications

AbstractIn this paper, a simple and compact coplanar waveguide (CPW)-fed four coexisting inverted-L-shaped radiating elements based wideband (ILW) multi-input and multi-output (MIMO) antenna has been presented for wearable wireless applications. The 50 Ω CPW feed structure has been used to excite the four inverted-L-shaped radiators in a wide square slot of the proposed four-port wearable MIMO antenna. The four diagonal strips are extended from the corners of the wide square slot to form a square split ring structure in the center, which suppresses the coupling of electromagnetic waves among coexisting compact quad inverted-L-shaped radiators. The proposed ILW wearable MIMO antenna achieves a wide −10 dB simulated impedance bandwidth of 58.18% (3.9–7.1 GHz) and more than 30 dB isolation along with much reduced envelope correlation coefficient (&lt;0.0002), high diversity gain (&gt;9.9 dB), and specific absorption rate lower than 1 W/kg in the entire operational band. The simulated results are in good agreement with the measured ones. This ensures its utility for several wearable wireless applications in the C-band that comprises WLAN (5 and 5.2 GHz), Wi-MAX (5.5 GHz), and ISM band (5.8 GHz) applications.

Dual Notched Four-Port Multiband Reconfigurable MIMO Antenna with Novel Fork-Radiator and Ω-shaped Ground

In the proposed communication, a 2 × 2 and 4 × 4 antenna array with the capability of rejecting dual interfering bands is presented for multiband wireless applications including Ultrawideband (UWB) and X-band. Reconfiguration of notched bands is controlled using high-frequency switching devices (RF-PIN diodes). MIMO antenna configuration is formed by the combination of the Fork-shaped patch providing wideband bandwidth with Γ-T-shaped stub attached with the patch, which acts as bandstop filters for WiMAX and WLAN bands on one plane. Novel Ω-shaped ground is printed on the opposite plane, which provides good matching of impedance. The good matching of the results suggests accuracy in simulation and measurement environment with prototype in terms of frequency, time-domain, far-field and diversity MIMO performance.

Characteristic Mode-Based Neutralization Line Design for MIMO Antenna

Based on the theory of characteristic modes (TCMs), this paper proposes a systematic design procedure to guide the design of a neutralization line (NL) for a dual-band multiple-input-multiple-output (MIMO) antenna to achieve high isolation. According to the direction of the current flow of significant characteristic modes, coupling and uncoupling modes are identified and a metal NL is appropriately designed to cancel the coupling modes. More specifically, it introduces new currents opposite in direction to the original coupling characteristic currents, thus reducing mutual coupling. Compared with the traditional NL design method, the proposed approach simplifies the optimization process and saves lots of optimal design time. As an illustration of the proposed design method, we design another dual-band antenna operating in the WLAN bands with a compact size of 50 mm × 48 mm × 0.8 mm and minimum edge‐to‐edge space between the radiating elements with 0.033λ0 of the lower band. The impedance bandwidths for S11 ≤ -10 dB are 0.42 GHz (2.27–2.69 GHz) and 0.24 GHz (5.6–5.84 GHz). A fabricated prototype shows good agreement between the measured and simulated results. The introduced NL improves the isolation degree by about 18 dB for the 5.8 GHz band, and the total efficiency of the antenna was also improved. In addition, the proposed antenna also has a low envelop correlation coefficient (ECC &lt; 0.3), high diversity gains, and low total active reflection coefficient (TARC) in the frequency band of interest. Measurement results show that the proposed MIMO antenna system is suitable for WLAN applications.

A Compact On/Off-Body Dual Band Antenna with Modified Ground for Healthcare Applications

ABSTRACT In this paper, a compact dual-band radiator with a modified ground structure is presented for on/off body communication. The antenna is capable of resonating in the ISM-I (2.4 GHz) and WLAN (5.15–5.85 GHz) bands. The proposed antenna consists of a novel compact ring loaded with a C-shaped radiator for dual-band operation. To improve impedance matching and shifting of the lower band at the ISM-I band, a modified ground structure is used. This suggested antenna has a small footprint of 0.24λ0×0.22λ0×0.016λ0, wherever λ0 is the free space wavelength at the lower operational frequency. The proposed antenna is parametrically studied, as well as the analysis of electric field and SAR at different positions on the arm are also carried out to check its utility for medical applications. The proposed antenna's specific absorption rate (SAR) meets IEEE standards and the prototype's measured findings validate the simulation's results.

DESIGN OF A DUAL-BAND REJECTION PLANAR ULTRA-WIDEBAND (UWB) ANTENNA

This article discusses about a small Ultra-wideband fix radio wire with two score channels. Spaces are embedded into the fix of the receiving wire to give WiMAX and WLAN recurrence band dismissal. The radio wire is displayed with the economically accessible CST Microwave Studio apparatus. The opening size are steadily changed and tuned to get the ideal band dismissal reactions. The gathered outcomes show that the radio wire capacities admirably across the whole operational frequency spectrum (3.1 GHz to 10.6 GHz), with the exception of the notched WiMAX (3.3-3.7 GHz) &amp; WLAN (5.1-5.8 GHz) bands. Additionally, the antenna was built &amp; the simulation results were gathered.

Parasitic element loaded efficient electrically small antenna for indoor wireless applications

AbstractThis study presents an electrically small antenna loaded with a parasitic loop resonator for dual‐band operations. The proposed configuration covers 2.4 GHz Bluetooth/Wi‐Fi, 5G new radio (n79), and 5 GHz WLAN bands. In this study, a coplanar waveguide (CPW) feed L‐shaped driven element is capacitively coupled with a parasitic loop resonator to get a dual‐band response centered at 2.43 and 5.5 GHz, respectively. Further, an open‐ended stub is attached with the driven element to achieve wide impedance bandwidth over the 5 GHz WLAN band. The overall dimension of the proposed antenna is 0.06λ × 0.2λ, where λ is the wavelength at 2.43 GHz. The parasitic loop resonator loaded electrically small antenna offers 60 and 1580 MHz impedance bandwidth (S11 &lt; −10 dB). The stable impedance bandwidth and radiation characteristics of the proposed antenna validate its suitability for wireless application(s).

High gain wideband and multi-band on-demand reconfigurable antenna for modern wireless application

AbstractThis paper proposes a wide band and multiband frequency reconfigurable antenna that can operate in the UWB, GSM, GPS, 4G LTE, WLAN, and WiMAX bands. The antenna is made up of a trapezoidal-shaped monopole radiator, which was inspired by a rectangular monopole antenna. The ground plane is modified by embedding T and L-shaped slots to notch the desired operating frequency. The proposed antenna can switch to six different frequencies using RF PIN diodes, making it suitable for modern wireless applications. A multilayer frequency selective surface (FSS) reflector is presented to improve the gain of the proposed reconfigurable antenna. The low-profile design achieved a significant increase in gain while retaining the UWB antenna's excellent impedance bandwidth. Because of the use of the FSS reflector, the antenna's average peak gain has increased from 6 to 10.4 dBi. The proposed antenna has a wide switching capability, which validates its unique feasibility for high-speed multiple Internet of Things applications via a common embedded platform under various applications.

Miniaturized ultra-wideband filter with independently controlled notch bands for 5.1/6/8 GHz wireless applications.

A novel three-mode step impedance resonator (TSIR) is developed to design a miniaturized multi-pole microstrip planar ultra-wideband (UWB) filter with independently controlled notched bands at different frequencies is presented in this work. The basic UWB filter consists of four L-shaped λ/4 short-circuited stubs operating in the range of i.e. 2.7 to 12.1 GHz with fractional bandwidth (FBW) 127%, and the TSIR is constructed using two T-shaped λ/2 open ended step impedance resonator (SIR) and one λ/4 short-circuited uniform impedance resonator (UIR) is coupled to the basic UWB design in order to achieve the stopbands performance at 5.1 GHz, 6 GHz, and 8 GHz, to supress the unwanted bands of WLAN, Wi-Fi 6E, and X-band satellite communication system, respectively. Commercial full-wave electromagnetic (EM) software HFSS-13 was used to design an ultra-compact structure having size 0.07 λg×0.02 λg on Rogers RT/Duroid 5880 substrate to justify good agreement between simulated and measured S-parameters.

An SIC-Fed Low-Profile Wideband Metamaterial-Based Antenna Array for 5G Wireless Cellular Networks

In this paper, we propose a metamaterial (MTM)-based low-profile wideband antenna and its array using a substrate integrated cavity (SIC) feed structure for 5G wireless cellular networks. The proposed wideband antenna consists of two sets of square mushroom-like arrays; a semi-ground plane and a microstrip line-fed bow-tie radiator. Due to the unique in-phase reflection characteristic of the mushroom-like metamaterial, the bow-tie antenna wideband performance is maintained while the distance between the bow-tie radiator and the metamaterial-based semi-ground is considerably reduced to 0.014λ0 (λ0 is the operating wavelength at 5 GHz in free space), thereby satisfying the compact size requirement desirable in many wireless communication systems. The in-phase reflection of the mushroom unit cell is applied to analyze and explain the wideband performance of the presented antenna. The proposed dielectric-filled (εr=3.55) MTM-based wideband antenna element has an overall size of 1.0λ0 × 0.8λ0 × 0.054λ0 and attains a measured (|S11|&lt;−10 dB) bandwidth of 31.3%. Subsequently, an SIC feed structure is employed to form an array antenna, and a measured (|S11|&lt;−10 dB) bandwidth of about 17% is obtained. Across the operating bandwidth, which partly covers the 5G wireless communication in the sub-6 GHz band and 5-GHz WLAN, the antenna array achieved an average gain of 6.6 dBi and a radiation efficiency greater than 73%.

Design of a Compact Quasi-Self-Complementary UWB-MIMO Antenna with Dual Band-Notched Characteristics for Wireless Communication Applications

ABSTRACT The proposed work contains a quasi-self-complementary (QSC) half-cut flower-shaped ultra-wideband (UWB) multiple-input multiple-output (MIMO) antenna with dual-band-notch characteristics. The overall size of the antenna is 27 × 39 mm2, which offers impedance bandwidth from 2.67 GHz to 11.7 GHz. The inter-port isolation is more than 15 dB over the FCC defined UWB range of frequencies. A reverse 2-shaped slit is etched off from a flower-shaped patch to reject the interfering WiMAX/C-band (3.28–4.19 GHz), whereas an inverse P-shaped stub is placed near the feed arm a notch at the WLAN band (5.1–6.15 GHz). Further, the performance of the proposed antenna is analysed by comparing the simulated results with the fabricated ones. Moreover, diversity parameters such as envelope correlation coefficient (ECC), channel capacity loss (CLL), mean effective gain (MEG), effective diversity gain (EDG) and total active reflection coefficient (TARC) are computed, which makes the proposed QSC UWB-MIMO antenna a suitable candidate for high-speed wireless applications.

Compact Wearable UWB MIMO Antenna with Reduced Mutual Coupling and Notch Characteristics of WLAN Band

Compact Wearable UWB MIMO Antenna with Reduced Mutual Coupling and Notch Characteristics of WLAN Band

Design and analysis of clover leaf‐shaped fractal antenna integrated with stepped impedance resonator for wireless applications

SummaryA novel multi‐band clover leaf‐shaped fractal antenna with integrated filtering to reduce higher order harmonics has been proposed. Existing microstrip filtering antennas endure limited gain, narrow impedance bandwidth, and undesired frequency radiations. The proposed antenna is designated to operate simultaneously in following operating bands: 3.35–3.6 GHz for WiMAX, 5.156–5.825 GHz for WLAN, 5.7–6.4 GHz for Intelligent Transport Systems (ITS), and 7.7–8.5 GHz for ITU‐R applications. The proposed patch is realized by combining two semi‐fractal ring microstrip patches like the geometry of a three‐leaf clover with dual‐layered stepped impedance resonator (SIR) integrated at bottom layer of the second substrate. The SIR bandpass filter exhibits odd and even modes suppresses higher order harmonics and undesired radiations. An aperture coupled feeding in the proposed patch offers better bandwidth and impedance matching. The number of iterations is increased to get the desired multiband characteristics. The proposed microstrip fractal antenna has the geometrical dimensions of 50 × 50 × 2 mm3. It is observed that both the simulated and measured results offers peak gain of &gt;5 dBi and better return loss (S11), that is, 3.3–3.6‐GHz band offers S11 of −33.73 dB, 5.15–5.825‐GHz band offers S11 of −36.69 dB, and 5.795–6.4‐GHz band shows the S11 of −36.25 dB, and for 7.725–8.5 GHz, the return loss is −33.209 dB. Harmonics at 6.42 GHz (1.8f0), 7.37 GHz (1.5f0), and 9.04 GHz (1.73f0) has been suppressed and shows linear polarization in the WLAN band and circular polarization in the ITU‐R and WiMAX bands.

Design and performance analysis of a compact, wideband dual polarized antenna for WLAN &amp; WiMAX applications

Abstract Dual polarization is achieved by putting a rectangular or circular patch in between two orthogonal gaps. At the beginning a single-polarized patch is considered. Then by using anequivalent circuit, the impedance matching property of the gap is being configured. After optimization of the length of the patch and width of the gap, a dual polarized antenna is being considered. Here in this article we projected a new technique to design dual polarized microstrip antenna for WLAN, WiMAX, wireless applications using circular patch. By combining all resonant modes we have finally achieved a wide operating bandwidth. Experimental result of the projected antenna shows the operating bandwidth of 21.56% (5.24–6.37 GHz) for (differential mode S-parameter) S dd11 ≤ −10 dB with a high port isolation of 40 dB and a relative gain of 13.5 dBi is achieved. From the result analysis this antenna finds its applications for various WLAN and Wi-MAX frequency band.

Compact ultrawideband filter with reconfigurable band notch characteristics

ABSTRACT A novel compact ultrawideband (UWB) filter with reconfigurable band notch property is presented. Stepped impedance slotline (SISL) resonator along with two open-ended coupled microstrip is used for the realisation of UWB filter. The WLAN band of rejection is obtained by placing the U-shaped DGS near the SISL resonator. Furthermore, two capacitors are placed in the active slot of U-shaped DGS to obtain WiMAX band of rejection. The proposed UWB filter with reconfigurable band notched characteristics is fabricated and measured. The measured results agree well with the simulated results.

Design of dual band-notched UWB hexagonal printed microstrip antenna

AbstractThis article presents the design and performance analysis of a printed microstrip ultra-wideband (UWB) antenna consisting of the slots in the ground plane and radiating patch. A meandered S-shaped slot has been introduced on the patch and an inverted U-shaped slot has been incorporated in the ground plane to realize the band-notch effect for WiMAX (3.2–3.8 GHz) and WLAN (5.1–5.8 GHz) bands respectively. The total dimension of the proposed design is 44 × 44 mm2. The fabricated antenna exhibits wide impedance bandwidth of 10 GHz (2.4–12.4 GHz), i.e., 135% of center frequency. The design prototype is fabricated, and the measured results have good agreement with simulated values. The effects of the slots have been analyzed by simulated surface current distribution. The designed antenna shows almost omnidirectional radiation patter and stable gain. The proposed hexagonal antenna may be suitable for UWB applications removing WiMAX and WLAN bands.

The Design of Closed Square RR Loaded 2-Port MIMO for Dual Band Applications

In this paper, a closed square ring resonator loaded 2-port Multi Input Multi Output (MIMO) is proposed for dual-band applications in the S and C band. The presented antenna model is designed by loading it in FR-4 substrate with a feedline of 50Ω and loaded with SRR for the enhancement of isolation and radiation pattern. Ansoft HFSS is used to obtain the simulated parameters of the model for the frequency ranges of 2.2-2.5 and 6-6.3GHz. Measurements confirm the characteristics of the fabricated antenna that were speculated with the simulation results with a little shift in frequencies. The diversity parameter performance analysis justifies the working performance of the 2-port MIMO for WiFi, WLAN, and ISM band applications.

A compact super wideband antenna with stable and improved radiation using super wideband frequency selective surface

A small bulb shaped planar super wideband (SWB) antenna with the dimension of 35 × 30 × 0.8 mm3 operating over 2.8–40 GHz (14.28:1) spectrum is proposed. The antenna offers a fractional bandwidth of 173.8%, bandwidth dimension ratio (BDR) of 1904, measured peak gain of 5.5 dBi and radiation efficiency of 80%. The proposed antenna is unified to an unique SWB frequency selective surface (FSS), having unit cell size equal to 0.114λL × 0.114λL × 0.008λL (λL is the wavelength at 3.1 GHz). The FSS operates in 3.05 to 35.92 GHz spectrum (168.7%) with transmission level S21 ≤ -10 dB and reflection S11 near 0 dB for TE and TM modes of polarization with adequate angular stability. The linearly decreasing S11 phase of FSS makes it appropriate for radiation improvement of the bulb shaped antenna in the broadside direction by placing the antenna at the top of FSS with an optimal air gap of 19 mm. The SWB ‘antenna-FSS’ exhibits wideband response over 3–36.2 GHz (169.4%) spectrum, including commercial ultra-wideband (3.1–10.6 GHz), ISM bands (5.725–5.875 GHz & 24–24.25 GHz), WiMAX (3.3–3.7 GHz), IEEE 802.11 WLAN bands, S-C-X-Ku-Ka bands, and 5G NR (n77, n78, n79, n257, n258, n261) bandwidth with stable and adequate gain of 5.2–7.16 dBi and an acceptable radiation efficiency.

Compact reconfigurable antenna system for spectrum interweaved cognitive radio

This article discusses the design of a compact antenna system for spectrum interweaved cognitive radio (CR). The system consists of a sensing filtenna and three communicating antennas. The sensing ultra-wideband (UWB) antenna is a coplanar-waveguide (CPW)-fed monopole (2.2–11 GHz). The narrowband communicating patch antennas are reconfigurable through a switching mechanism, operating in six different frequency bands (5.54, 6.12, 7.60, 8.25, 9.64, and 10.29 GHz). To block the Wi-MAX and WLAN bands, the proposed design uses a meandering slot and a stepped U-slot in the monopole. Analysis of communicating antennas using the theory of characteristic mode analysis indicates good radiation in the desired frequencies. Isolation among these antennas is better than −18 dB. A constant group delay and linear phase response indicate a good time-domain performance of the proposed UWB antenna. Simulated results match closely with those from measurements on the prototype. The proposed antenna system can find applications in various sectors adopting CR like internet of things.