WLAN has been implemented widely, including in public area and government office. Badung Regency office has got benefit from the technology in applying its e- government services. However the WLAN ...performance in term of its QoS has not been evaluated after its installation. Then its delay, packet loss, throughput, and jitter were measured using Ekahau Heatmapper, Axence Nettols, Wi-Fi Analyzer, and Ubiquiti Unifi. The WLAN coverage area was calculated and analyzed. Generally, the performance is good. However there are areas in all 12 buildings in the offices that are needed more access points.
To prevent interference problems due to existing nearby communication systems within an ultrawideband (UWB) operating frequency, the significance of an efficient band-notched design is increased. ...Here, the band-notches are realized by adding independent controllable strips in terms of the notch frequency and the width of the band-notches to the fork shape of the UWB antenna. The size of the flat type band-notched UWB antenna is etched on 24 times 36 mm 2 substrate. Two novel antennas are presented. One antenna is designed for single band-notch with a separated strip to cover the 5.15-5.825 GHz band. The second antenna is designed for dual band-notches using two separated strips to cover the 5.15-5.35 GHz band and 5.725-5.825 GHz band. The simulation and measurement show that the proposed antenna achieves a wide bandwidth from 3 to 12 GHz with the dual band-notches successfully.
Defected ground structure (DGS) using an array of the three split ring resonators inspired antenna for the Wireless Local Area Network(WLAN) and RFID sensor is proposed in this manuscript. The ...complete physical measurement for the proposed antenna is 50 X 40 mm2 (at lower operating frequency). The defected ground plane structure along with the inclusion of the square split ring resonators (SRRs) in the ground plane helps in gain and bandwidth improvement. 1 × 3 split ring resonator array is used to make the existing ground plane to be defected. The cost effective FR – 4 materials is used as a substrate for the fabrication with the standard thickness of 1.6 mm. The resonance frequencies are at 2.4 and 5.8 GHz having the average gain 2.65dBi. The impedance bandwidths for both the frequencies are 5.0 % (2.31 to 2.49 GHz) and 3.9% (4.9 to 6.1 GHz). The dipole and omni directional radiation patterns, overall gain and efficiency of around 75% make the antenna most practically possible for the RFID and WLAN devices.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A novel retransmission scheme, considering both transmission rate and frame error rate, is proposed to alleviate the inefficiencies caused by head-of-line blocking and null padding problems during ...retransmission in IEEE 802.11be synchronous multi-link wireless local area networks. Simulation results show that the proposed scheme improves throughput by up to 200% over the legacy scheme by reallocating lost subframes and adding effective duplicate subframes to multiple links.
A monopolar patch antenna with a V-shaped slot for car-to-car (C2C) and wireless local area network (WLAN) communications is presented in this paper. To widen the impedance bandwidth of the antenna, ...techniques for adding a shorting pin and a V-shaped slot are applied to an equilateral triangular patch. By properly placing the shorting pins on an equilateral triangular patch, two operating modes, i.e., TM10 and TM20, are obtained. The presence of the V-shaped slot can generate an additional TM11 mode. These three resonances found in the operating frequency bandwidth resulted in a wideband characteristic. The proposed antenna can operate from 4.82 to 6.67 GHz for the reflection coefficient ≤ -10 dB with the gain of around 5.0 dBi. In addition, an omnidirectional radiation pattern is yielded by a coaxial center-fed probe excitation. The antenna has a thickness of 0.09λ g (at the center frequency of 5.5 GHz), which is easily hidden on the roof of a vehicle for C2C communication. This proposed design can also be used as indoor base-station antennas for WLAN communication.
•Great improvements of densification and microwave dielectric properties are achieved in cold sintered BaF2 ceramics.•The optimum microwave dielectric properties are obtained as follows: εr = 7.3, ...Qf = 82,320 GHz, and τf = –109.4 ppm/°C.•A microstrip patch antenna with excellent performance is fabricated using BaF2 ceramics as the substrate.
BaF2 is a low-firing fluoride with excellent microwave dielectric properties, while the densification of BaF2 ceramics is challenging via conventional sintering. In this work, dense BaF2 ceramics with 95.3~98.5% relative densities have been prepared via the cold sintering (150–600 MPa, 150 °C, 1 h) and following post-annealing at 900 °C. The scanning electron microscope images demonstrate closely packed microstructures, and the chemical compatibility between BaF2 ceramics and Ag electrodes is identified. The optimum Qf (82,320 GHz) is 1.53 times higher than that obtained via conventional sintering (53,654 GHz), with a dielectric permittivity, εr = 7.3, and a temperature coefficient of resonant frequency, τf = –107.9 ppm/°C. Furthermore, a BaF2-based microstrip patch antenna is fabricated, which realizes an S11 = –16.5 dB, a high gain of 5.84 dB, and total efficiency of −0.38 dB at 5.78 GHz. The exceptional microwave dielectric properties and antenna performances indicate that BaF2 ceramics are promising candidates for 5.8 GHz wireless local area network applications.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A novel approach of frequency tunability to cover multiple wireless applications by using four PIN diodes as a switching element is presented. Five switching modes of PIN diodes are analyzed for ...frequency tunability. The parasitic metamaterial superstrate achieves performance improvement shown in the design. Numerical analysis of metamaterial rings and equivalent circuit models of the SRR and PIN diode are also presented. The structure is analyzed regarding reflection response (S
11
), Gain, VSWR, directivity and E-field for 2 GHz-6 GHz. Computational analysis is performed by the HFSS simulator and is compared with the fabricated structure (FR-4) for verification. Copper and liquid-based material are used for performance analysis of all the models, and comparative analysis is included. Liquid-based split ring resonator provides a maximum total gain of 5.564 dB, reflection response of −43.36 dB and tunability of 510 MHz. The proposed antenna is used in 5G, WLAN, WiMAX and LTE applications.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Abstract
A dual-band multiple-input multiple-output (MIMO) antenna with enhanced isolation operating in 2.35–2.50 GHz and 5.13–5.88 GHz bands is investigated and presented. The proposed antenna ...system is deformed from two inverted-F antennas, and the distance between the antenna elements is only 0.104
λ
(
λ
—wavelength of 2.4 GHz). To enhance isolation and reduce mutual coupling, the metamaterial and slot structures are efficiently and innovatively designed on the ground plane for two bands. Both decoupling methods effectively improve the antenna isolation, with metamaterials acting on the lower band and slots acting on the higher band. The mutual coupling at 2.4 GHz and 5.5 GHz is reduced by 15.24 dB and 8.19 dB, respectively. Then, the optimized MIMO antenna can cover both 2.4 GHz and 5 GHz wireless local area network (WLAN) bands, and has the advantages of wideband, compact size, good radiation, enhanced isolation, and low envelope correlation coefficient. The measured results agree with the simulated results, which shows that the proposed MIMO antenna system has potential application value in WLAN system.
As the most popular technology, Wi-Fi is built based on Wi-Fi standards in many consumer areas. Up to now, Wi-Fi has experienced more than 20 years of development. The launch of the first generation ...protocol IEEE802.11 has a low popularity because it is not competitive in transmission speed and distance. With the proposal of the third generation 802.1g protocol, IEEE adds the backward compatibility feature to the new protocol. For 802.11 protocol, new technologies will be adopted in each iteration, so as to improve the network performance. Until the latest generation protocol, IEEE802.11ax launched in September 2019 has been called Wi-Fi 6.
Wi-Fi-6 has greatly improved its performance. It introduces uplink MU-MIMO, OFDM orthogonal frequency division multiple access, 1024-qam high-order modulation and other technologies to solve the problems of spectrum resource utilization and multi-user access. Even if Wi-Fi-6 continues every new WLAN standard for a long time and only makes the conventional upgrade of single stream throughput, the main motivation behind Wi-Fi-6 is to improve the experience quality of MU-MIMO users and achieve this goal by minimizing the overall delay. Therefore, higher spectrum and the effective and efficient sharing of the spectrum have become the key to achieve the minimum capacity.
This paper also puts forward some views on the cooperation between 5G and Wi-Fi-6. For Wi-Fi networks, it has a faster update cycle than mobile networks. In addition, when users' usage habits are formed, the possibility of Wi-Fi network being replaced is low. Although 5G and Wi-Fi-6 differ in performance, they have their own advantages. They are suitable for different scenarios. 5G will have better performance in outdoor open places, such as car networking, while indoor Wi-Fi network can meet the more economical demand for high-speed Internet access, such as VR, smart home, etc.
In the third chapter of this paper, it focuses on the demand of Wi-Fi-6 driven by the development of high-quality network connection and Internet of things.
First of all, when Wi-Fi-6 was designed, high-density and high-capacity network service support has been considered, which is also the reason for supporting Wi-Fi-6 to be used in outdoor large-scale public places, indoor high-density wireless office and electronic office. However, because 5g has more advantages in the application of outdoor environment, indoor is the key application scenario of Wi-Fi-6. It is also because people's demand for information consumption, entertainment and smart device links has promoted the development of Wi-Fi-6.
Secondly, the demand for high-quality network connection is prominent. With the promotion of national policies, it will help to speed up the construction of HD video content. As the main carrier of indoor transmission, Wi-Fi will be popularized more effectively when the terminal penetration continues to improve.
Thirdly, the demand for the Internet of things is gradually increasing. Unlike users such as laptops, IOT devices need deterministic wireless services. Therefore, enterprise Wi-Fi-6 has increasingly become the preferred platform for the indoor Internet of things. Compared with Wi-Fi-5 and 4G, Wi-Fi-6 has faster speed and can transmit data like lightning. Moreover, Wi-Fi-6 has improved in security and scalability respectively. The previous Wi-Fi router supports 250 devices to connect at the same time, but this is insignificant in front of Wi-Fi-6 that can support up to 1024 devices at the same time. Therefore, Wi-Fi-6 is ideal and economical for families and small businesses.
Finally, Wi-Fi-6 realizes the intelligent industrial scene. Although 5g and Wi-Fi-6 can now increase the rate to about 10gpbs due to technological improvements. However, because 5g network construction has just started, Wi-Fi-6 currently has greater advantages in the industrial field. Most factories have generally adopted wired network connection to realize Wi-Fi communication.
In the fourth chapter, this paper also summarizes the rapid expansion of Wi-Fi-6 market.
Today, the WLAN market is in a steady upward trend, and the Wi-Fi-6 application scenario is getting better. It is expected that the Wi-Fi-6 market will reach 24 billion yuan in 2023, which means that the chips supporting Wi-Fi-6 standards account for nearly 90% of the total. In terms of market segments, the market scale of router / gateway Wi-Fi-6 chip in China is about 300 million yuan in 2019 and is expected to exceed 4.5 billion yuan in 2023.
In the past two years, the development speed of Wi-Fi-6 is obvious to all. From new mobile phones of major brands to routers, products supporting Wi-Fi-6 technology continue to emerge.
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