Local Area Network Applications Research Articles

Combined Shark-Fin Rooftop Antenna for LTE, WLAN and BeiDou Applications

This paper presents rooftop automobile antennas designed for Long-Term Evolution (LTE), Wireless Local Area Network (WLAN) and navigation system applications. The proposed antennas are housed within a shark-fin structure on the car’s roof, and comprise a main antenna and a diversity antenna. The main antenna and diversity antenna combine for spatial diversity, receiving and processing the same signal to optimize signal quality. To accommodate the limited space within the shark-fin housing, various miniaturization and multiband techniques are utilized. The hexagonal substrate is more closely fitted to the shape of the shark fin, thus making full use of the space of the shark-fin shell. The main antenna and the diversity antenna are perpendicular to each other, which saves the space of the overall antenna and improves the utilization rate of the overall antenna space. The proposed main antenna, compactly sized at 50 mm × 20 mm × 1.59 mm, maintains a VSWR value below 2 across the frequency range of 1.19–2.8 GHz, enabling support for LTE bands 1, 2, 3, 4, 7, 11, 15, 16, 34, 39, 40, and 41, as well as WLAN 2400 bands. The diversity antenna maintains a VSWR value below 2 across the frequency range of 1.5–2.6 GHz, which can cover BeiDou B1-1, LTE 1, 2, 3, 4, 7, 11, 15, 16, 34, 39, and 40, and WLAN 2400 bands. The main antenna and the diversity antenna both demonstrate favorable radiation patterns on the azimuth plane. Simulation and measurement results exhibit a high level of agreement.

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.

Eight-Element Dual-Band Multiple-Input Multiple-Output Mobile Phone Antenna for 5G and Wireless Local Area Network Applications.

This paper proposes an eight-element dual-band multiple-input multiple-output (MIMO) antenna that operates in the fifth generation (5G), n78 (3400-3600 MHz), and WLAN (5275-5850 MHz) bands to accommodate the usage scenarios of 5G mobile phones. The eight antenna elements are printed on two long frames, which significantly reduce the usage of the internal space of the mobile phone. Each antenna element is printed on both surfaces of one frame, which consists of a radiator on the internal surface and a defected ground plane on the outer surface. The radiator is a rectangular ring fed by a 50 Ω microstrip line which is printed on the top surface of the system board. A parasitic unit is printed on the outer surface of each frame, which is composed of an inverted H-shaped and four L-shaped patches. Each parasitic unit is connected to the internal surface of the frames through a via, and then it is connected to a 1.5 mm wide microstrip line on the top surface of the system board, which is connected to the ground plane on the bottom surface of the system board by a via. Four L-shaped slots, four rectangular slots, and four U-shaped slots are etched onto the system board, which provides good isolation between the antenna elements. Two merged rectangular rings are printed on the center of each frame, which improves the isolation further. The return loss is better than 6 dB, and the isolation between the units is better than 15 dB in the required working frequency bands. In addition, the use of a defected ground structure not only makes the antenna element obtain better isolation but also improves the overall working efficiency. The measurement results show that the proposed MIMO antenna structure can be an ideal solution for 5G and WLAN applications.

Bandwidth and Gain Enhancement of Microstrip Leaky-Wave Antennas with Slot and Defected Ground Structure

This paper discusses the design, simulation, and realization of a leaky-wave microstrip antenna with multiple slots and defected ground structure (DGS). The leaky-wave microstrip antenna with multiple slots and DGS was designed to operate at 5.925-6,425 GHz for wireless local area network applications (WLANs), with a gain of ≥4dBi. The antenna uses FR-4 epoxy as the substrate with a dielectric constant of 4.6 and a thickness of 1.6 mm. The leaky-wave microstrip antenna has dimensions of 45.1 mm × 24.8 mm × 1.6 mm, while the leaky-wave microstrip antenna with multiple slots and DGS has dimensions of 40.6 mm × 25 mm × 1.6 mm. The simulation results showed that adding multiple slots and DGS to the leaky-wave microstrip antenna increased the bandwidth from 280 MHz (5.859–6.139 GHz) to 691 MHz (5.854–6.545 GHz) while the gain increased from 4.47 to 5.04 dBi. Meanwhile, the measurement results showed that the bandwidth parameter increased from 273 MHz (5.877–6.150 GHz) to 684 MHz (5.845–6.529 GHz) and the gain parameter from 4.53 to 5.06 dBi at 6 GHz.

High-gain printed monopole antenna with dual-band characteristics using FSS-loading and top-hat structure

In this paper, a printed monopole antenna with high-gain and dual-band characteristics for applications in wireless local area networks and the internet of things sensor networks is presented. The proposed antenna consists of a rectangular patch with multiple matching stubs surrounded to improve the impedance bandwidth of the antenna. The antenna incorporates a cross-plate structure which is seated at the base of the monopole antenna. The cross-plate consist of metallic plates aligned perpendicularly which enhances the radiations from the edges of the planar monopole to maintain uniform omnidirectional radiation patterns within the antenna’s operating band. Furthermore, a layer of frequency selective surface (FSS) unit cells and a top-hat structure is added to the antenna design. The FSS layer consist of three unit cells printed at the back side of the antenna. The top-hat structure is placed on top of the monopole antenna and comprises of three planar metallic structures arranged in a hat-like configuration. The coupling of both the FSS layer and the top-hat structure presents a large aperture to increase the directivity of the monopole antenna. Thus, the proposed antenna structure realizes a high gain without compromising the omnidirectional radiation patterns within the antenna’s operating band. A prototype of the proposed antenna is fabricated where good agreement is achieved between the measured and full-wave simulation results. The antenna achieves an impedance bandwidth |S11| < − 10 dB and VSWR ≤ 2 for the L and S band at 1.6–2.1 GHz and 2.4–2.85 GHz, respectively. Furthermore, a radiation efficiency of 94.2% and 89.7% is realized at 1.7 and 2.5 GHz, respectively. The proposed antenna attains a measured average gain of 5.2 dBi and 6.1 dBi at the L and S band, respectively.

A 200-MS/s 10-Bit SAR ADC Applied in WLAN Systems

This paper introduces a new high-performance successive approximation register (SAR) analog-to-digital converter (ADC) designed for high-speed and low-power wireless local area network (WLAN) applications using a SMIC 55 nm 1p8m CMOS process. The design employs several innovative techniques, including an improved bootstrap switch with high linearity, a 4-reference voltage method to minimize capacitive digital-to-analog converter (CDAC) mismatch, a kickback-canceling comparator to eliminate kick-back noise, and redundant design-assisted window-opening SAR logic to decrease conversion time. Experimental results reveal that the proposed ADC achieves an impressive signal-to-noise and distortion ratio (SNDR) of 55.3 dB and a spurious-free dynamic range (SFDR) of 66.6 dB at a sampling rate of 200 MHz with Nyquist frequency input while consuming a power of 2.8 mW at a 1.2 V power supply. This corresponds to a figure-of-merit (FoM) value of 29 fJ/conversion-step. Thanks to the incorporation of the 4-reference voltage method, the ADC demonstrates a significant area advantage compared to other designs with similar FOM values utilizing more advanced processes, occupying a mere 0.008 mm2 of core area.

2.4 GHz Active Inductor Based Single to Differential LNA for WLAN Applications

This paper presents a source degenerated cascode LNA design using a regulated cascode active inductor (AI). The AI has an inductance value of up to 6.28 nH, a Q-value of up to 4750, and a resonant frequency of up to 9.758 GHz. The proposed AI replaces the passive source degenerated inductor and load inductor in the LNA. Further, an active balun is used to have a differential signal at the LNA output to support the mixer stage. The gain and noise figure of the LNA is 22.2 and 5.6 dB respectively. The 3rd order input intercept (IIP3) value is 1.92 dBm and the return losses at the input port and two output ports are less than −10 dB. The power consumption of the circuit is 27 mW at a 1.8 V supply and the figure of merit (FoM) is 9.17. The area occupied by the AI is 39 × 72 µm2 and balun-LNA is 0.872 × 0.62 mm2. The complete proposed circuit is meant for wireless local area network (WLAN) applications in the 2.4 GHz frequency band.

Broadband Multiple Input Multiple Output antenna for sub‐6‐GHz 5G communications

SummaryThis paper presents the design of a miniaturized broadband monopole antenna for 5G and Wireless Local Area Network (WLAN) applications in mobile handsets. The proposed monopole evolved from a rectangular geometry of size 12 × 5 mm. The slot and stub loading techniques are used to improve the impedance matching offered by the antenna. Furthermore, bandwidth broadening is achieved using lumped elements loaded onto the aperture of the antenna. The proposed miniaturized antenna exhibits a measured impedance bandwidth of 63.6% (3.0–5.8 GHz) covering the 5G spectrum allocations under sub‐6 GHz and the WLAN services. The antenna elements are replicated along the sides of the mock mobile handset PCB to study the functionality of the eight‐element MIMO antenna. The prototype MIMO antenna fabricated and tested in the laboratory offers a peak gain of 3 dBi and total efficiency greater than 72%. Owing to miniaturization, the spatial distribution of the antenna element provides a low envelope correlation (ECC) of less than 0.2 and good diversity gain (DG) greater than 7.8 dB. In addition, the mean effective gain (MEG), channel capacity loss (CCL), multiplexing efficiency (ME), and total active reflection coefficient (TARC) are evaluated and presented. The estimated MIMO metrics are within the desired range of operation and hence make the antenna suitable for a complex propagation environment. The prototype antenna is developed on a thin microwave laminate with low‐loss characteristics and tested under laboratory conditions. The outcomes indicate that the proposed eight‐element antenna can be applied to 5G MIMO communications.

A Simulation Study of Triband Low SAR Wearable Antenna

The proposed paper presents a flexible antenna that is capable of operating in several frequency bands, namely 2.45 GHz, 5.8 GHz, and 8 GHz. The first two frequency bands are frequently utilized in industrial, scientific, and medical (ISM) as well as wireless local area network (WLAN) applications, whereas the third frequency band is associated with X-band applications. The antenna, with dimensions of 52 mm × 40 mm (0.79 λ × 0.61 λ), was designed using a 1.8 mm thick flexible kapton polyimide substrate with a permittivity of 3.5. Using CST Studio Suite, full-wave electromagnetic simulations were conducted, and the proposed design achieved a reflection coefficient below −10 dB for the intended frequency bands. Additionally, the proposed antenna achieves an efficiency value of up to 83% and appropriate values of gain in the desired frequency bands. In order to quantify the specific absorption rate (SAR), simulations were conducted by mounting the proposed antenna on a three-layered phantom. The SAR1g values recorded for the frequency bands of 2.45 GHz, 5.8 GHz, and 8 GHz were 0.34, 1.45, and 1.57 W/Kg respectively. These SAR values were observed to be significantly lower than the 1.6 W/Kg threshold set by the Federal Communication Commission (FCC). Moreover, the performance of the antenna was evaluated by simulating various deformation tests.

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.

A single‐layer differential‐fed dual‐band filtering antenna for WLAN application

AbstractIn this letter, a single‐layer differential‐fed dual‐band filtering antenna for wireless local area network application is proposed. The proposed antenna consists of a square patch, and two pairs of stepped impedance resonators (SIRs). The lower operating passband is realized by exciting the square patch with a pair of differential ports. Then, a pair of SIRs is connected with the radiating edge of the square patch to introduce another resonance, thus forming the upper passband. And a radiation null is simultaneously produced to enhance the frequency selectivity between the two passbands. Moreover, another pair of SIRs is utilized to connect with the nonradiating edge of the square patch, which generates an additional high‐frequency in‐band resonance and a radiation null to further improve the bandwidth and frequency selectivity of upper passband. The developed prototype was fabricated and measured to verify the design concept. The measured results are in good agreement with the simulated ones, demonstrating that it exhibits −10 dB fractional impedance bandwidths of 3.68% and 7.35%, maximum realized gains at boresight direction of 5.5 and 8.7 dBi, and cross‐polarization levels smaller than −30 dB, in lower and upper passbands, respectively.

Circularly polarized three-element MIMO antenna with diversity and polarization reconfigurability techniques

This paper proposes a circularly polarized (CP) three-element multiple-input multiple-output (MIMO) antenna system with diversity and polarization reconfigurability techniques for wireless local-area network (WLAN) applications. The proposed MIMO antenna system employs two CP antennas with endfire characteristics and a broadside slot antenna. The polarization reconfigurability technique is achieved using pin diodes in all three antenna elements. Additionally, the three antennas have distinct directional radiation patterns, improving the MIMO antenna system's diversity performance. The three-element MIMO antenna system is fabricated for validation, and antenna parameters are measured. For all the states, the proposed antenna provides good antenna characteristics for the WLAN frequency band (5.15 GHz − 5.35 GHz). The three-element MIMO antenna exhibits good port-to-port isolation, and MIMO parameters like total active reflection coefficient (TARC), channel capacity loss (CCL), envelope correlation coefficient (ECC) and diversity gain (DG) are within the acceptable range.

A Coupled-Fed Broadband Dual-Polarized Magnetoelectric Dipole Antenna for WLAN and Sub-6 GHz 5G Communication Applications

This paper presents a novel coupled-fed broadband dual-polarized magnetoelectric dipole antenna for wireless local area network (WLAN) and 5G communication applications. The proposed magnetoelectric dipole antenna is composed of a planar electric dipole and shorting pins as a magnetic dipole to obtain a broad operation frequency band. Two coupled microstrip lines perpendicular to each other are coupled through a cross-shaped slot to excite the vertical and horizontal polarizations. The proposed antenna features a simple structure, high gain, and high polarization isolation. The measured impedance bandwidth of the proposed antenna is 1.8–4.2 GHz (fractional bandwidth of 80%). The measured realized antenna gain value is 3.7–8.5 dBi, and polarization isolation level is 25 dB at the operation frequency band.

Design and characterization of frequency reconfigurable honey bee antenna for cognitive radio application

&lt;span lang="EN-US"&gt;In this article, a frequency reconfigurable honey-bee compact microstrip monopole antenna is proposed which is fed by a microstrip line (50 Ω) having the capability of providing dual-band as well as triple-band operation in eight distinct modes. By embedding three PIN diodes overs the honey bee arms, the effective current distribution is controlled hence resonant frequency is also changed in eight distinct modes in real-time. This is the reason the proposed antenna is portrayed as a frequency reconfigurable antenna in this paper which is suitable for cognitive radio application. This proposed antenna can be used for various wireless application such as Bluetooth, Wi-Fi, worldwide interoperability for microwave access (WiMAX), wireless local area network (WLAN), C-band, and X-band applications. The proposed antenna possesses a planner geometry of 39×34×0.87 mm&lt;sup&gt;3&lt;/sup&gt; which is printed on a substrate as flexible FR-4 (lossy) (ε&lt;sub&gt;r&lt;/sub&gt;=4.4 and tanδ=0.019). The proposed antenna exhibits voltage standing wave ratio (VSWR)&amp;lt;2 for all 19 resonant frequencies of interest and perceptible radiation pattern over entire frequency bands with a positive gain. CST microwave studio is used to find out all simulated results of antenna parameters.&lt;/span&gt;

Printed collinear dipole array antenna with a horizontally omnidirectional pattern for dual‐band WLAN

AbstractA dual‐band printed dipole array antenna for a wireless local area network (WLAN) application is presented. A radiation element consists of four pairs of printed dipoles, and two radiation elements are collinearly arrayed. A broadside coupling microstrip line‐based two‐sectional impedance transformer is used to feed the radiation elements in parallel. The proposed dual‐band antenna is designed to cover the dual‐frequency bands (2.4–2.48 and 5.15–5.825 GHz) which are the lower‐ and upper‐frequency bands for WLAN operation. The experimental results support the proposed design theory and also exhibit the gain values of 3.89–4.88 and 5.79–7.18 dBi at the lower‐ and upper‐bands, respectively, maintaining the omnidirectional radiation pattern. The measured radiation efficiencies at each frequency points, 2.4, 5.2, and 5.5 GHz are 87.39%, 75.43%, 69.96%, and 73.07, respectively. In addition, for mass production, the effect from a low‐cost flexible coaxial cable, and polyethylene housing on the antenna performance is also investigated in this letter.

Gain and bandwidth enhancement of slotted microstrip antenna using metallic nanofilms for WLAN applications

Structural modifications on microstrip patch antenna design for performance enhancement offer improvements and advantages only up to a certain limit. However, with the use of novel material in the patch area, the performance of a microstrip patch antenna can further be enhanced in terms of gain and bandwidth. In this paper, a nanomaterial-based slotted rectangular microstrip patch antenna is proposed for gain and bandwidth enhancement in Wireless Local Area Network (WLAN) applications. A conventional copper rectangular microstrip antenna (MSA) with a rectangular slot in the patch area is first fabricated and then nanomaterial is deposited in the slot area. Two types of metallic nanoparticulate thin films are deposited using Gold Nanoparticles (Au NPs) and a combination of alternate Silver-Gold-Silver Nanoparticles (Ag-Au-Ag NPs) in the slot area and the antenna parameters analyzed. A comparison between the conventional slotted MSA, and the fabricated antenna with the two different nanoparticulate thin films is presented. It is found that the Au NPs based antenna shows a 12.5 % improvement in bandwidth for a return loss of −31 dB and a 0.5 dB enhancement in gain with a nanomaterial film thickness of 264 nm. The composite Ag-Au-Ag NPs based antenna shows even better performance than the former one with an 18.75 % improvement in bandwidth for a return loss of −30 dB along with gain enhancement of 2 dB with a nanomaterial film thickness of 330 nm. Both the Au NPs and Ag-Au-Ag NPs based antennas are found to resonate at 5.89 GHz and 5.81 GHz showing an electrical size reduction of 32.09 % and 31.15 %, respectively compared to the conventional rectangular MSA.

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.

Performance Analysis of 1x4 RMPA Array using Step Cut and DGS Techniques with Different Feed Techniques for LTE, Wi-Fi, WLAN and Military Communications

This paper presents four different models of 1x4 antenna arrays excited by quarter wave transformer and mitered bend feeding techniques. These four antennae were designed and developed to examine the various radiation performance characteristics. The Ansys HFSS tool was used to simulate the four antenna models over the frequency range (1-5GHz). The simulation results were compared to identify the optimized design model. Both types of 1X4 arrays with mitered bend feed network showed better results than quarter wave transformer and were resonating at 2.4, 3.6, 4.5 and 4.7 GHz frequencies with a maximum gain of 13.118dB. The proposed antennae are suitable for Wi-Fi, Long Term Evolution (LTE), Wireless Local Area Network (WLAN) and military communication applications. The optimized four 1x4 array models were fabricated and tested using Vector Network Analyzer E507C. The measured results had good matching with the numerical values of the simulation results.

Design of Dual-Band, 4-Ports MIMO Antenna-Diplexer Based on Quarter-Mode Substrate Integrated Waveguide

Here, a compact, dual band, 4-elements multi-input and multi-output (MIMO) antenna diplexer is designed to use in wireless local area network (WLAN) applications. The antenna is accomplished in a planar profile by employing Substrate Integrated Waveguide (SIW) technology. To reduce the size of a single element by 75%, a quarter-mode substrate integrated waveguide (QMSIW) technology is introduced. The QMSIW is realized by bisecting the full-mode SIW along the two magnetic walls and considering the quarter-mode for the operation. Initially, two-QMSIW cavities of distinct dimensions are designed to operate in two frequency bands, 5.2 GHz and 5.8 GHz, respectively. Later, two more radiating elements operating at the same frequencies are integrated with a 2-elements antenna. For better polarization decoupling, the identical elements are placed perpendicular to each other, and a parasitic metallic strip loaded with shorting vias is placed between two identical frequency antenna elements; hence, the port isolation is improved up to −25 dB. The antenna covers a bandwidth of 1.8% in the lower frequency band while 2.2% in the upper frequency band. The antenna prototype is fabricated, and its results are verified with experimental data. It is observed that the measured results are closely following the simulated results.

Reference-Modulated PI-DCSK: A New Efficient Chaotic Permutation Index Modulation Scheme

In this paper, we propose a reference-modulated permutation index differential chaos shift keying (RM-PI-DCSK) over multipath fading channels. Due to quasi-orthogonal property between different permutated chaotic signals, the proposed scheme can remarkably suppress the inter-sequence interference to recover the desired information. Moreover, the proposed RM-PI-DCSK has one more modulation bit in the reference segment than the conventional permutation index differential chaos shift keying (PI-DCSK). Both the reference signal in the first time-slot and a permuted replica of the reference in the second time-slot are modulated for efficient transmission. The theoretical bit-error-rate (BER) performance and the highly consistent simulation results demonstrate that the proposed RM-PI-DCSK can achieve a performance gain 3 dB over the conventional PI-DCSK at a BER of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$10^{-4}$</tex-math></inline-formula> , and this gain becomes larger in a high-delay-spread channel. In particular, the performance superiority of the RM-PI-DCSK is further demonstrated in a typical ultra-wideband (UWB) channel with narrow-band interference. Therefore, this proposed scheme can be deemed as an efficient transmission alternative for chaotic-based wireless communications, such as in wireless local area network (WLAN) applications and indoor applications of the transmitted-reference UWB.