GHz Wireless Local Area Network Research Articles

A low‐profile four‐degrees of freedom antenna by collocating a ±45°‐polarized dipole and a dual‐polarized microstrip antenna with broadside radiations

AbstractThis letter proposes a novel four‐degrees of freedom (4‐DOFs) antenna for 5.8 GHz wireless local area network band communications. The proposed antenna realizes 4‐DOFs with a low profile (0.11λ), which is composed of ±45°‐polarized dipole (DP), an artificial magnetic conductor (AMC) reflector, and a dual‐polarized slot‐loaded microstrip antenna (MA). The whole size of the proposed antenna is 83 mm × 83 mm × 5.9 mm (1.6λ × 1.6λ × 0.11λ). The DP is printed on the substrate with the wideband characteristic, and the MA operates at TM50 mode. The AMC reflector operating for the DP is designed for the low profile, causing the low isolations between the DP and the MA. The broadside radiation with 4‐DOFs is first reported. The envelope correlation coefficients are lower than 0.07, and the DOFs are 3.75. The measured results are in accord with the simulated results.

Development of Long-Range and High-Speed Wireless LAN

The development of long-range and high-speed wireless LAN (Local Area Network) technologies has become increasingly important in modern networking applications. We have developed 2.4 GHz wireless LAN units with the longest coverage, which comply with the IEEE 802.11g standard and Indian radio regulations, to re-establish communications temporarily between disaster-devastated areas and hospitals, among other locations. The network deployment is carried out in the college campus, involving two types: a) point-to-point (PtP), and b) point-to-multipoint (PtMP). The throughput within ranges of 500m and 6Km is approximately 100 Mbps, while for 15Km, the achieved throughput was 80 Mbps. Real-world applications and use cases of long-range wireless LAN systems are also highlighted to demonstrate their significance in diverse scenarios, ranging from rural connectivity to urban deployments

Textile Bandwidth-Enhanced Half-Mode Substrate-Integrated Cavity Antenna Based on Embroidered Shorting Vias.

A textile bandwidth-enhanced half-mode substrate-integrated cavity (HMSIC) antenna based on embroidered shorting vias is designed. Based on the simulated results of the basic HMSIC antenna, two embroidered hollow posts with square cross-sections are added as shorting vias at the intersections of the zero-E traces of the TM210HM and TM020HM modes to shift the TM010HM-mode band to merge with the bands of the higher-order modes for bandwidth enhancement. A prototype is practically fabricated based on computerized embroidery techniques. Measurement results show that the prototype is of an expanded -10 dB impedance band of 4.87~6.17 GHz (23.5% fractional bandwidth), which fully covers the 5 GHz wireless local area network (WLAN) band. The simulated radiation efficiency and maximum gain of the proposed antenna are above 97% and 7.6 dBi, respectively. Furthermore, simulations and measurements prove its robust frequency response characteristic in the proximity of the human tissues or in bending conditions, and the simulations of the specific absorption rate (SAR) prove its electromagnetic safety on the human body.

Slots and stubs incorporated annular ring-shaped compact microstrip antenna with circular polarization characteristics for wireless UWB communication systems

A circularly polarized (CP) antenna with ultra-wideband resonance and a broad axial ratio bandwidth is designed for UWB communication systems. The prescribed design comprises of a modified annular ring-shaped radiator and a modified step-graded slots loaded partial ground plane. The projected antenna is prototyped on FR4 substrate of 35 × 30 × 1.6 mm3. To achieve wide axial ratio bandwidth, a rectangular vertical slot is inserted into the radiating patch and two stubs are embedded into the monopole ground plane, which is configured with step graded rectangular slots. The simulation results are verified by testing the fabricated protype. The proposed design operates at UWB spectrum with an ultra-wide impedance bandwidth (IBW) of 134.57%, centered at 10.7 GHz, covering 3.5 GHz to 17.9 GHz frequency spectrum. Furthermore, it demonstrates circular polarization characteristics with a broad axial ratio bandwidth (ARBW) of 96.29% expanding from 3.5–10 GHz (6500 MHz). Its peak gain reaches to 8.7 dBi and a maximum radiation efficiency of 95% is achieved within the operating band. The results (measured and simulated) obtained in terms of S11, axial ratio, gain and efficiency and radiation patterns exhibit high agreement. The presented antenna could be a suitable choice for 5.5 GHz Worldwide Interoperability for Microwave Access (Wi-Max), 5.2/5.8 GHz Wireless local area network (WLAN), X-band satellite communication (downlink: 7.25–7.745 GHz, uplink: 7.9–8.4 GHz), UWB communication systems, and other applications in microwave C, X, Ku bands due to its superior characteristics.

Microstrip Planar Antennas for C-Band Wireless Applications

In recent years, wireless communications have evolved significantly, and many mobile devices have reduced in size. The antennas used in mobile terminals must be lowered in size to fulfil the downsizing standards. Planar antennas, like microstrip and printed antennas, have a low profile, compact size, and conformability to mounting hosts, making them particularly desirable candidates for achieving these needs. Additionally, planar antennas are also being used in communication devices for 2.4 GHz (2400 – 2484 MHz) and 5.2 GHz wireless local area network (WLAN) systems (5150). In wireless applications, an antenna is a crucial component. At the transmitter, it transforms electrical signals into RF signals, and at the receiver, it converts RF signals to electrical signals. The patch inside the antenna is made of a conducting material such as Cu (Copper) or Au (Gold), and it can be rectangular, round, triangular, or elliptical. Two unique designs of microstrip planar antennas with an operating frequency of 5.2 GHz having S11 parameters as -16.0 dB and -15.7 dB have been offered and their performance has been studied in this research article.

Compact microstrip patch antenna loaded with Artificial Transmission Line for wireless applications

ABSTRACT This article presents an efficient yet simple spiral antenna design methodology for 2.44 GHz Wireless Local Area Network (WLAN) applications. In the suggested design, the antenna’s radiating section is redesigned with a particular Artificial Transmission Line (ATL) construction that allows for good downsizing. Circuit analysis and electromagnetic solver are used to verify the design, which demonstrate good agreement with the measured results. The electromagnetic simulation and passive component analysis reveal that the new design matches the traditional designs in terms of frequency tuning and size reduction. The overall footprint of the proposed ATL design is (33 × 25 × 1.6) mm3 which equals to 0.2684λ×0.2033λ×0.013λ, where λ is the distance travelled by the wave per cycle at the operating frequency of 2.44 GHz. The antenna has a gain of 3.8dBi and a 50Ω impedance. Modifying the interdigital capacitance and inductance used in the ATL structure to achieve a longer electrical length of the line can also improve the wave guide mode of excitation. As a result, the phase constant is regulated, allowing for good antenna size minimisation. The effect of interdigital inductance and capacitance on the operating bands is also analysed.

EMC Hybrid Loop/Monopole LDS Antenna With Three-Sided Ground Walls for 2.4/5/6 GHz WLAN Operation

A multi-resonant, electromagnetic-compatible (EMC), hybrid laser- direct-structuring (LDS) antenna capable of operating in the 2.4, 5, and new 6 GHz wireless local area network (WLAN) bands is presented. The LDS metal patterns are formed on a holder with the volume of 8 mm × 10 mm × 30 mm and comprise an inner loop, a parasitic strip, and three-sided, vertical ground walls. The fundamental and the first higher-order resonance of the parasitic strip acting as a shorted monopole generate the 2460 and 6460 MHz modes. In addition, two loop modes formed by the inner loop with the parasitic strip and the inner loop only, respectively, contribute to the 5420 and 7020 MHz resonance. All of these together generate a tri-WLAN-band, 2.4/5/6 GHz operation. The vertical ground also functions as the shielding walls that assorted conductive components can be placed in the close vicinity of the design for compact integration. The proposed antenna applied to laptop computers for the most recent Wi-Fi 6E operation is demonstrated in this article.

Design of single‐layer bandstop fractal frequency selective surface based on WLAN applications

AbstractIn this letter, we present a new frequency selective surface (FSS) for shielding 2.4–2.5 and 4.98–5.825 GHz wireless local area network (WLAN) bands. This FSS structure is based on the traditional Sierpinski octagon and we improve it. Compared with the traditional structure, the improved one has a smaller element size and better angular stability. The design is realized on float glass with a relative permittivity () of 8, and the unit cell size is 0.1152λ0 × 0.1152λ0 (λ0 is the free space wavelength at the first resonant frequency). Wide rejection bandwidths (−10 dB) of 910 and 1630 MHz are obtained at 2.4–2.5 and 4.98–5.825 GHz, respectively. The surface current distribution and the equivalent circuit model are illustrated to explain the resonance behavior of the proposed FSS. Furthermore, this FSS exhibits stable frequency response to incident angles of 0°–80° under transverse electric and transverse magnetic polarizations. Finally, this FSS structure was fabricated and measured. The measured results demonstrate that this FSS structure has good performance in WLAN applications.

A single layered broadband circularly polarized MIMO antenna based on metasurface with aperture CPW feed

ABSTRACT In this paper, a single-layered broadband circularly polarized MIMO antenna is presented for a 5 GHz wireless local area network (WLAN). The Metasurface is designed with an array of patches and these patches are excited by four uniform aperture CPW feed MIMO antennas. The stubs are added across the aperture and central patches at respective apertures are increased to achieve broad bandwidth. Truncated corner square patches are used for the metasurface to achieve circular polarization (CP). The CP MIMO antenna has achieved an impedance bandwidth of 33% (4.35 GHz-6.08 GHz), a 3 dB axial ratio (AR) bandwidth of 11.95% (5.18 GHz-5.8 GHz) and a gain of 8dBi.

A Dual-Band MIMO Antenna System for 2.4/5 GHz WLAN Applications

A compact multiple-input-multiple-output (MIMO) microstrip antenna system covering the 2.4- and 5- GHz wireless local area network (WLAN) bands is presented in this paper. To achieve dual-band characteristic, the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> and TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">03</sub> modes of a microstrip antenna are excited. A rectangular slot is etched in the center of microstrip antenna for improving the radiation capability of the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">03</sub> mode. Then, two probes are utilized to tune the resonant frequency of the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> mode with limited effect on the operating frequency of the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">03</sub> mode. To realize high inter-port isolation at the two distinct WLAN bands in a methodological way, isolation enhancement is achieved successively at the lower and upper frequency bands. Two split loops are introduced to reduce the mutual coupling at the 2.4-GHz band. Two dipole elements are added in the rectangular slot to obtain high isolation at the 5-GHz band. The decoupling mechanism of the proposed antenna is detailed analyzed. The proposed antenna system operates at 2.25-2.63 GHz and at 5.14-6.06 GHz. The measured maximum value of mutual coupling between the two ports is less than -15.3 dB at both operating frequency bands.

Design and Analysis of CPW Fed Antenna with Triangular Separated Stub for Wireless Applications

One of the most active areas of research in the field of communication systems today is wireless technology, and a study of communication systems would be lacking without a grasp of how antennas work and are constructed. We offer a straightforward and small printed ultra-wideband antenna with dual-band notched properties. A redesigned ground plane and a rectangular patch make up the proposed antenna. The lossy FR4 substrate is etched with the rectangular patch. The rectangular patch that a U-shaped slot has embedded in it is parasitized by a circular ring strip. A rectangular slit, two inverted-L slits, and a slit are imbedded into the ground plane. The antenna structure uses some bandwidth improvement and bandnotched techniques to widen the bandwidth and create notches. With dual-notched bands of 3.30-4.20 and 5.10-5.85 GHz, the proposed antenna covers the 3.3/3.7 GHz WiMAX, 3.7/4.2 GHz C-band, and 5.2/5.8 GHz wireless local area network systems. This is demonstrated by the simulated and measured results, which indicate that the proposed antenna offers a very wider bandwidth ranging from 3.04 to 17.30 GHz, defined by the return loss less than 10 dB.

Dual-Band Decoupling for Two Back-to-Back PIFAs

In this communication, two dual-band back-to-back planar inverted-F antennas (PIFAs) are presented for wireless local area network (WLAN) applications. By simply etching a slot on the PIFA, the PIFA can simultaneously radiate at the WLAN 2.4 GHz (2.4–2.484 GHz) and WLAN 5 GHz (5.15–5.835 GHz) bands. To reduce the mutual coupling at the two independent bands in a guided way, long and short slots are successively engraved on the ground. The detailed decoupling process is given and discussed. The antenna was fabricated and measured. The measured results show that the two PIFAs cover the 2.4 and 5 GHz WLAN bands and the isolation can be improved to higher than 20 dB at the two independent bands.

2.4GHz Wireless Local Area Network Optimization in University Dormitory Buildings

This article describes the wireless network problems met in University dormitory buildings, especially under 2.4GHz spectrum. Through wireless network optimization such as channel re-allocation and transmission power adjustment manually, the performance of the wireless LAN could be improved a lot even for real-time services such as video and live broadcast.

A Compact-Size and High-Efficiency Cage Antenna for 2.4-GHz WLAN Access Points

In this communication, a compact-size and high-efficiency air cavity antenna with a cage-like structure is proposed for 2.4 GHz wireless local area networks (WLAN). The air cavity antenna is constructed with four sides of hybrid metallized vias, including sparsely arranged blind vias and tightly arranged shorting vias. First, the antenna size is significantly reduced by utilizing the shorting vias, which makes the antenna operate at the high-order TM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\mathrm {1/2,1/2}}$ </tex-math></inline-formula> mode. Then, by loading the capacitive blind vias at the radiating apertures, the antenna size is further miniaturized. Notably, high radiation efficiency is obtained attributed to the lower dielectric loss of the air-medium structure. Finally, a prototype of the proposed cage antenna has been fabricated and tested with good agreement between simulated and measured results. In such a compact size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.128\lambda _{0} \times 0.128 \lambda _{0} \times 0.10 \lambda _{0}$ </tex-math></inline-formula> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{0}$ </tex-math></inline-formula> is the free-space wavelength at the center frequency), the measured total efficiency over 90% is achieved in the WLAN band by the cage structure. Compared with the existing 2.4 GHz antennas, the proposed one is with the ascendency of compact size and high radiating efficiency for WLAN applications.

An EBG-Based Triple-Band Wearable Antenna for WBAN Applications.

In this article, a triple-band wearable monopole antenna fed by a coplanar waveguide (CPW) with an integrated electromagnetic bandgap (EBG) array is proposed. The monopole antenna consists of an asymmetric inverted U-shaped strip, a horizontal branch, and an L-shaped ground stub, which can generate the 2.45/5.8 GHz wireless local area network (WLAN) band and the 3.5 GHz worldwide interoperability for microwave access (WiMAX) band. To reduce the influence of antenna radiation on the human body, a triple-band 3 × 3 EBG array has been integrated into the back of the monopole antenna. The EBG unit is composed of two rectangular rings and a circular ring, and the operating frequencies correspond to the triple bands of the monopole antenna. In this paper, the impedance and radiation performances of the stand-alone monopole antenna and the integrated antenna are analyzed, and the safety for the human body is evaluated based on specific absorption rate (SAR) values. The proposed triple-band antenna can be used in wearable devices in wireless body area networks (WBANs).

Bandwidth enhanced deltoid leaf fractal antenna for 5.8 GHz WLAN applications

A wideband deltoid leaf fractal antenna is proposed for 5.8 GHz commonly used in industrial scientific and medical (ISM) and wireless local area networks (WLAN) applications. A microstrip patch antennas is designed with leaf shape radiating element. Using a leaf shape, it is possible to increase the perimeter of a design and thus reduce the overall dimensions of the antenna. A circular ring slot is made on the leaf shaped radiator, in a way that a circular disc is loaded at centre. Triangular fractal slots are made inside the circular disc to make it miniaturized. A partial ground is maintained with slot at centre. The antenna is fed by micro-strip feed. The locality and measurements of the fractal slots are varied to make the antenna radiate at 5.8 GHz with wider bandwidth (BW) of (2.26 GHz). The complete size of the antenna is 40 mm 3 × 40 mm 3 × 1.6 mm 3 . The step-by-step implementation of the antenna and the effects of its dimensions are compared and presented using the reflection coefficient curve. The measured reflections coefficient |S11|&lt;-10 dB maintained the operational band from (5.36 GHz - 7.62 GHz), with gain 4.2 dBi. The proposed antenna is planned and simulated using high frequency structure simulator (HFSS). The simulated and measured comparison showed good agreement, the designed antenna is suitable for 5.8 GHz WLAN applications with wider bandwidth requirements.

Energy-Aware Hybrid RF-VLC Multiband Selection in D2D Communication: A Stochastic Multiarmed Bandit Approach

To handle the exponentially growing service expectations from mobile users and circumvent the band switching slow rate, device-to-device (D2D) communication is receiving much research attention in the Internet of Things (IoT). While the emerging D2D nodes can support heterogeneous frequency bands [radio frequency (RF) including 2.4 GHz/5 GHz wireless local area network (WLAN), 38-GHz millimeter wave (mmWave), and visible light communication (VLC)], the physical constraints (e.g., blocking) require the user devices to dynamically switch between the bands in order to avoid the loss of connectivity and throughput degradation. In this article, we investigate an effective online link selection in hybrid RF-VLC scenarios for direct user data handling. First, we model the multiband selection issue as a multiarmed bandit (MAB) problem. The source/relay node acts as a player who gambles to maximize its long-term feedback/reward via selecting suitable arms, i.e., available bands (WLAN, mmWave, or VLC). Then, we propose an online, energy-aware band selection (EABS) methodology by leveraging three theoretically guaranteed MAB techniques [upper confidence bound (UCB), Thompson sampling (TS), and minimax optimal stochastic strategy (MOSS)] to derive optimal band selection policies. Based on these adopted policies, we propose three algorithms, namely, EABS-UCB, EABS-TS, and EABS-MOSS, to implement the EABS strategy, respectively. Extensive simulations demonstrate our proposed algorithms’ superior performance compared to the traditional link selection schemes regarding energy efficiency, average throughput, and convergence rate. In particular, EABS-MOSS emerges as the best algorithm as it exhibits near-optimal performance due to its flexibility to both stochastic and adversarial environments.

Multi-standard planar compact 4-port MIMO with enhanced performance for ISM/5G NR/C/WLAN/X band applications

In this research, a compact 4-port Multiple-Input-Multiple-Output (MIMO) antenna with dual band is proposed for 5 GHz Wireless Local Area Network (WLAN) and 5 G New Radio (NR) sub-6 GHz n77/n78/n79 band applications. An identical element is used for designing MIMO antenna and each element is excited by coplanar waveguide (CPW) feed technique. To achieve low mutual coupling among the antenna's elements along with compactness of presented MIMO antenna, a top ring resonator is shorted with the ground plane using strip line. It can resonant in the range from 1.9 GHz to 3.6 GHz and from 4.2 GHz to 11.6 GHz, respectively and isolation is achieved with level − 18 dB. Also, equivalent circuit model of proposed MIMO design is analyzed. The overall size of proposed four element MIMO antenna is only 30 × 30 × 1.6 mm3. The designed antenna is fabricated on FR-4 substrate and measured results well matched the simulated results. Also, MIMO parameters for diversity performance check is analyzed and studied and shows good applicant for multiple applications in wireless technology such as UMTS/LTE/Wi-Fi/WLAN/ISM/5 G cellular communication/sub-6 GHz/X- band.

Textile Via-Loaded Bandwidth-Enhanced Half-Mode Substrate-Integrated Cavity Antenna for WLAN Communications

A textile via-loaded bandwidth-enhanced half-mode substrate-integrated cavity (HMSIC) antenna is presented in this article for wireless local area network (WLAN) communications. A strategy for adding shorting vias within the cavity is proposed based on the simulated <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${E}$ </tex-math></inline-formula> -field distributions of different modes of the HMSIC antenna. More specifically, the number and positions of vias are studied for maximum shift of lower resonance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\rm TM_{1,1,0}^{HM}$ </tex-math></inline-formula> mode) so that it merges with higher resonance (rotated <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\rm TM_{2,2,0}^{HM}$ </tex-math></inline-formula> mode) to achieve a wide 10 dB return loss impedance band. Two prototypes of the designed structure are realized using textile manufacture techniques. A first realization uses embroidered sidewalls to create the cavity and metallic rivets for the shorting vias, and a second prototype uses embroidered vias and a stripline feed. The proposed antenna can operate from 5.09 to 5.9 GHz with a fractional bandwidth of 14.7% according to measurements. The simulated radiation efficiency is above 95% in free space and 82% when worn on the human body in the 5 GHz WLAN band (5.15–5.825 GHz).

Ultra-Compact Slitted Flower-Shaped Dual-Band Monopole Antenna for Modern Portable Devices

A meanderingly slitted bio-inspired (MSB)-shaped antenna is presented in this work. The footprint of the proposed MSB antenna is 12 × 10 mm2 0.12 × 0.10 λ g 2 at 2.1 G H z . The MSB antenna proposed in this operates at 2.1 GHz and 5.2 GHz frequencies with a bandwidth of 70 MHz and 570 MHz and a radiation efficiency of 52.5% and 96%, respectively, which is suitable for UMTS, radio navigation, Long Term Evolution (LTE), and 5 GHz Wireless Local Area Network (WLAN) applications. The proposed MSB antenna demonstrates a peak gain of 2.9 dBi at 5.2 GHz and an omnidirectional radiation pattern at both E-plane and H-plane in both operating bands. The fabrication and measurement of the proposed antenna prototype are presented. The parametric study of the proposed structure is performed and presented. Therefore, the proposed antenna is a promising candidate for modern portable devices.