Wireless Local Area Network Applications Research Articles

A Compact and Low-Profile MIMO Antenna Using a Miniature Circular High-Impedance Surface for Wearable Applications

A new miniature circular high-impedance surface (HIS) is used to design a compact and low-profile multi-in multi-out (MIMO) antenna for wearable applications. The antenna is designed to operate from 2.4 to 2.49 GHz for wireless local area network application. By employing a pair of degenerated characteristic modes of a circular loop antenna, the MIMO antenna can achieve a good port-to-port isolation (>15 dB) without increasing its geometric size. A four-element HIS is chosen to match the antenna profile, and a 2 dBi antenna gain improvement is observed. The design was optimized considering the effect of packaging and then a prototype with the optimal parameters was fabricated and tested. Measurement results are in good agreement with simulation results. Furthermore, the loading effect due to lossy human tissue is also considered and the results show that the antenna has a robust performance against the human phantom and a low specific absorption rate can also be obtained.

Single‐layer dual‐broadband circularly polarised annular‐slot antenna for WLAN applications

This study proposes a single-layer dual-broadband circularly polarised (CP) antenna that operates at 2.4, 5.2 and 5.8 GHz for wireless local area networks (WLAN) applications. An annular-slot antenna loaded with a lightning-shaped slot for achieving good CP radiation in the WLAN 2.4 GHz band is initially studied. To cover the WLAN 5.2 GHz band as well, the inner circular patch of the aforementioned design is modified as an inner ring patch loaded with a notch and a narrow U-shaped strip. By further embedding a crescent parasitic element into the circular slot of the inner ring patch, the upper CP band is significantly broadened to cover the WLAN 5.8 GHz. Accordingly, the final design can exhibit two wide 3 dB axial ratio bands of 13.3% (2.24-2.56 GHz) and 16.9% (5.01-5.94 GHz), and their corresponding 10 dB impedance bandwidths are 25.9% (2.21-2.86 GHz) and 25.9% (5.05-6.54 GHz). With the advantages of compact size, low-cost, easy integration and dual-broad CP bands, the proposed designs are very attractive for modern wireless communication systems, especially for WLAN applications.

Meander line MIMO antenna for 5.8 GHz WLAN application

A four port compact low profile planar MIMO antenna with meander line radiators and with polarization diversity effect has been proposed to cover 5.8 GHz wireless local area network application. The proposed MIMO antenna has −10 dB impedance bandwidth of 1.4 GHz (5.3–6.7 GHz) along with the compact size of 38 × 38 mm2 and an envelope correlation coefficient (ECC) of less than 4 × 10−4 in the whole band. The proposed antenna resonates at 5.8 GHz frequency, having return loss of −43.2 dB. The isolation between diagonal and opposite ports is more than 10 and 12 dB, respectively, in the presented frequency band. The total active reflection coefficient frequency response shows more than 1.0 GHz of bandwidth in the whole band. The antenna gain is more than 4.0 dBi in the operating frequency band. The radiating elements are very close to each other to make the design very compact.

Multiband slot‐loaded dipole antenna for WLAN and LTE‐A applications

A multiband printed dipole antenna for wireless local area network (WLAN) and long-term evolution-advanced (LTEA) applications is investigated here. Its multiband characteristic is enabled by the Y-slot present in the upper arm of the dipole, while the antenna's dimensions are 0.08λ o × 0.384λ o at the lowest operating frequency. It features bandwidth of 14.6% centred at 2.4 GHz, and ~30.5% centred at 5.5 GHz for WLAN operation. An additional bandwidth of 6.9% centred at 3.5 GHz supporting LTE-A applications is also featured. Besides being compact, the proposed antenna radiates omnidirectionally with a gain of up to 4.09 dBi. Simulations and measurements are in good agreement.

Compact Dual-band Parallel Coupled T-shaped SIR Filter for WLAN Applications

In this article, a new compact dual-band bandpass filter was introduced. The filter utilized two operating bands centered at 2.45 GHz and 5 GHz widely used for wireless local area network applications. The filter consists of T-shaped sections of step impedance resonator. The structure is an even symmetrical around electrical or magnetic wall, so the operation mechanism of the filter can be analyzed by an even- and odd-mode transmission line theory. The resonator structure is parallel coupled to a pair of 50 Ω input/output ports. Proper feeding and coupling structures can realize at least two transmission zeros around each of the operating band. To enhance the spurs rejection in the out of the band response of the filter, additive transmission zero at 10 GHz was created by adding stub of quarter guided wavelength at a selected distant from the output port edge. The filter is designed and optimized using the full wave Electromagnetic simulator. The center frequency of the designed bands can be easily refined by the filter dimensions. The overall dimension of the filter is (where is the guided wavelength at the frequency of 2.45 GHz) corresponding to 14.3 mm x 22 mm.

A compact trisection microstrip bandpass filter with frequency-dependent cross-coupling

ABSTRACTA compact microstrip bandpass filter using stub loaded ring resonators and double-loop ring resonators in an embedded triplet configuration with frequency-dependent cross-coupling is proposed in this article. The embedded triplet configuration is realized by putting the loops of the double-loop ring resonator into the circles of the stub loaded ring resonators. The frequency-dependent cross-coupling has been introduced to the filter by a manner of separate electric- and magnetic-coupling path. Three transmission zeros are obtained to enhance the frequency selectivity and stopband performance. Among them, two are achieved by the frequency-dependent cross-coupling, the other one is created by the harmonic effect of the transmission lines. The filter is designed for 2.4 GHz Wireless Local Area Networks application with 20.8% fractional bandwidth. The measured results show reasonable agreement with the simulated ones.

A Reconfigurable MIMO Antenna System for Wireless Communications

A reconfigurable antenna system is proposed to improve data throughput limitations in multiple input multiple output wireless communication systems in this investigation. The 4×4 MIMO antenna is designed to operate in the 2.4 and 2.6 GHz for Wireless Local Area Network (WLAN) and Long Term Evolution (LTE) applications. The system's radiation pattern re-configurability is realized by using the microcontroller-driven PIN diode switching concept. Simulations and measurements exhibited good agreements for the single, 2×2 MIMO and 4×4 MIMO configurations. The antenna is operational between 2.387 to 2.628 GHz, while the simulated and measured reflection coefficients are at least −24.3 dB. All configurations produced a narrow beam forward radiation, while the envelope correlation coefficient (ECC) and diversity gain for the two MIMO configurations are below 0.5 and at least 9 dBi, respectively.

Dual-Band Hybrid Antenna Structure With Spatial Diversity for DTV and WLAN Applications

This communication presents the design of a dual-band hybrid antenna for digital television (DTV) and wireless local area network (WLAN) applications. Radiations are produced with spatial diversity for WLAN applications to realize multiple-input–multiple-output functionality and omnidirectional coverage. The structure embeds two slots into an ultrawideband monopole body for high- and low-frequency operations, which are excited by three ports of DTV and WLAN. The resultant frequency bandwidth covers most of the global DTV frequencies and the free WLAN band at 2.45 GHz. The radiations exhibit omnidirectional patterns for all three cases. Numerical and measurement results are presented to demonstrate the characteristics of radiation.

Low‐Profile Dual‐Polarized Planar Antenna with Compact Structure for Base Stations

A low-profile dual-polarized planar antenna with compact structure for 2.4GHz Wireless local area network (WLAN) and 2.5GHz Long term evaluation (LTE2500) base stations is proposed. A combination of a planar radiator and compact Artificial magnetic conductor (AMC) reflector is utilized to achieve a full planar structure without adding extra matching circuit, an extremely low-profile of 0.127 wavelength, as well as a high front to back ratio (F/B) of 25dB. The antenna is fabricated to test the performance such as S-parameters, radiation patterns and peak gain. Reasonable results show the suitability of the proposed antenna for 2.4GHz WLAN and LTE2500 applications.

Determination of Directivity and Gain with Improved Performance of Smart Antenna

In wireless communication systems, smart antenna is designed to improve radiation in one direction and null out interference in other direction. This can be realized by increasing the directivity of the antenna element which leads to gain in a specific direction. At high frequency, transmission of signals is characterized with impairments. Mitigation of these signal impairments can be accomplished through the improvement of directivity and gain of smart antenna system at terahertz frequency range. This research work proposed and examined smart/ adaptive antennas array at terahertz (THz) frequency range, which can be applied for far distance communications and can be extended to the far-field region of antenna. The adaptive/smart antenna array is appropriately operational in the range of 300 GHz to 3 THz for wireless local area network (WLAN) applications that uses high-frequency (HF) radio waves. The efficiency of this adaptive array antennas system has been optimized and simulated with the aid of commercially available full-wave, Finite Element Method (FEM) based electromagnetic simulator Agilent’s Advanced Design Software (ADS).

Bioinspired transparent antenna for WLAN application in 5 GHz

AbstractIn this paper is developed a transparent antenna, bioinspired in ingae edulis mart plants, build in Indio Tin Oxide film, and flexible transparent dielectric of low cost (cellulose acetate), generated by Gielis formula, for wireless local area network application in 5 GHz (5.15–5.85 GHz). The measured bioinspired transparent antenna presented bandwidth of 4.11 GHz (4.50‐8.66 GHz), covering the WLAN band, with maximum gain of 5.44 dBi, and half power beamwidth of 126° at resonance frequency.

Design and Performance Study of a Differential Dual-Band Antenna-in-Package

ABSTRACTThis article presents a differential dual-band antenna-in-package (AiP) for wireless local area network applications. Dual-band operation is realized by a square ring and a pair of fork-shaped strips. For AiP, there will be an interaction between the antenna and packaged component, which usually takes place in the near field. By using two non-uniform via fences, the bandwidth at two bands is significantly improved, and the electric field in the package cavity is also effectively suppressed. The distribution of the electric field in the package cavity is analyzed, and then a method that arranges the via fences connecting the antenna ground and package ground is demonstrated. Simulation and experiment results show that the proposed AiP can operate at 2.4 and 5.2 GHz, and the relative impedance bandwidth is broadened to be 8.7 and 15.2%, respectively. Moreover, good radiation performances are achieved at two bands.

Dual‐band antenna with comb radiators for WLAN applications using SISL technology

A novel dual-band directional antenna with comb radiators using substrate integrated suspended line (SISL) technology is proposed for wireless local area network (WLAN) applications. The proposed SISL antenna is designed to be self-packaged using five substrate layers with embedded air cavities. H-shape strip and rectangle slot are used to achieve the band from 2.43 to 2.54 GHz with gain of 2.2 dBi. Via is utilised to connect the antenna patch with feeding line, then the second band from 5.33 to 6.22 GHz with gain of 10.1 dBi is obtained. Additionally, the cross-polarisation levels less than -15 dB and front-to-back ratio larger than 15 dB are achieved.

Design and Modeling of a Compact Reconfigurable Slot Antenna for WLAN Portable Devices

This paper presents design and modeling of acompact reconfigurable quarter wavelength slot antennacompatible with the portable devices of the 5GHz wireless localarea network (WLAN) applications. The concept of thetransverse resonant method which is used for the transmissionlines is utilized for modeling the proposed slot antenna. A PINdiode is used to switch the antenna operating band from thelower unlicensed indoor 5GHz WLAN band (5-5.3) GHz to theupper one (5.7-5.9) GHz and vice versa. Another PIN diode isattached to the feed line to provide suitable matching stublength for each operation mode. Furthermore, the shape of theradiating slot of the proposed antenna is modified to providean omnidirectional radiation pattern in the H-plane suitablefor the portable gadgets of the WLAN system. Themeasurements are in well agreement with the simulatedresults, and they verify the precision of the suggested modeland the enhanced matching characteristics for the twooperation modes of the proposed antenna

Compact triple‐band circularly polarized monopole antenna for WLAN and WiMAX applications

AbstractA novel compact triple‐band circularly polarized monopole antenna has been proposed for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. The antenna composes of a square patch etched with an X‐shaped slit and an improved ground plane. Furthermore, an inverted‐L slit is embedded in the square patch to improve axial ratio (AR) and impedance bandwidth. With a compact size of 44 × 46 × 1.5 mm3, the proposed antenna provides a relative wide 3‐dB AR bandwidth of 24.2% (2.22–2.83 GHz), 25.9% (2.92–3.79 GHz), and 9.3% (5.45–5.98 GHz), which successfully covering the bands of WLAN (2.4–2.484 GHz and 5.725‐5.850 GHz) and WiMAX (3.3–3.6 GHz).

A Modified Compact Ultra Wideband Antenna with Band Rejection for WLAN Applications

In this paper, a circular ultra wideband antenna is considered which comprises of a planar circular patch element on grounded FR4 substrate of 1.6 mm thickness generating the bandwidth of 6.8 GHz. To enable its extensive use in Wireless Local Area Network (WLAN) applications, it is modified by modulating the microstrip line to generate stopband from 5.9 to 9 GHz rejecting the extended C band and X band. The antenna ground plane is then drilled to form holes implementing EBG structures to obtain desired passband characteristics, from 1.97 to 2.65 GHz and 3.12 to 5.86 GHz suitable for WLAN(2.40–2.484/5.150–5.350/5.725–5.825 GHz) applications. The designed antenna shows good passband and stopband characteristics and return loss S11 and nearly omni-directional field pattern over the frequency band of the passband.

Design of frequency reconfigurable multiband compact antenna using two PIN diodes for WLAN/WiMAX applications

In this study, the authors present a simple reconfigurable multiband antenna with two PIN diode switches for worldwide interoperability for microwave access (WiMAX)/wireless local area networks (WLAN) applications. The antenna permits reconfigurable switching in up to ten frequency bands between 2.2 and 6 GHz, with relative impedance bandwidths of around 2.5 and 8%. The proposed antenna has been simulated using computer simulation technology microwave studio software and fabricated on an FR-4 substrate. It is compact, with an area of 50 × 45 mm 2 , and has a slotted ground substrate. Both measured and simulated return loss characteristics of the optimised antenna show that it satisfies the requirement of 2.4/5.8 GHz WLAN and 3.5 GHz WiMAX antenna applications. Moreover, there is good agreement between the measured and simulated results in terms of radiation pattern and gain.

Offset-fed complementary split ring resonators loaded monopole antenna for multiband operations

A miniaturized multiband monopole antenna based on rectangular-shaped Complementary Split Ring Resonators (CSRRs) with offset-fed microstrip line is proposed for Global System for Mobile Communication (GSM) and Wireless Local Area Network (WLAN) applications. The proposed antenna is fabricated on a FR-4 substrate having a dielectric constant (ɛr) of 4.4 within a small size of 19.18×22.64×1.6mm3. CSRRs in the monopole antenna create a multiband characteristics and bandwidth improvement, which is analyzed by use of the precise quasi-static design equations and electromagnetic simulation software (HFSS version 13). By selecting a proper offset-fed microstrip line, it is capable to achieve 50Ω characteristic impedance and good impedance matching. The parameter extraction procedure of the metamaterial property of the CSRRs is enlightened in detail, by which the negative permittivity existence and the new resonance frequencies are verified. Simulated and measured result coincides with each other. The measured H-Plane (azimuthal plane) exhibits omnidirectional radiation pattern and E-plane (elevation plane) shows a dipole like bidirectional radiation pattern. The proposed antenna has adequate advantages, including simple design, small size, lower return loss and capable of multiband operations.

A Compact Dual-Band CPW-Fed Planar Monopole Antenna for 2.62–2.73 GHz Frequency Band, WiMAX and WLAN Applications

In this paper, we present a compact and low-profile monopole antenna with a simple structure for the 2.6-2.73 GHz frequency band, the Worldwide Interoperability for Microwave Access (WiMAX) and the Wireless Local Area Network (WLAN) applications. The first configuration of our antenna mainly consists by three radiating elements: inverted L-shaped Stub1, L-shaped Stub2 and a rectangle Stub3. By adjusting the lengths of the three Stubs, three resonant frequencies can be achieved and adjusted separately. Then, the assembled between Stub2 and Stub3 gives the final design of our proposed antenna with a small overall size of 20 mm A— 37 mm A— 1.56 mm. From the experimental results it is observed that, the antenna prototype has achieved two operating bandwidths (S 11 ≤ -10 dB): the first band from 2.62 to 2.73 GHz (110 MHz) and a second broadband from 3.02 to 7.30 GHz (4280 MHz) which combines WiMAX and WLAN applications. The antenna also exhibits an almost omnidirectional radiation patterns over the operating bands. The parameters which affect the performance of the antenna in terms of its frequency domain characteristics are studied in this paper. The details of the monopole antenna design along with simulated and experimental results are presented and discussed.

A Compact UWB Monopole Antenna with Rejected WLAN Band using Split-Ring Resonator and Assessed by Analytic Hierarchy Process Method

The design of a compact micro strip line-fed Ultra-Wideband (UWB) monopole antenna with a notched-band characteristic is presented in this letter. The rejection frequency band occurs around 5- 6 GHz, which is appropriate for wireless local area network (WLAN) applications and is obtained by a split-ring resonator on the antenna ground. The proposed antenna is printed on FR4 substrate material with a dielectric constant of 4.4. The dimension of the proposed antenna is 24×16×0.8 mm 3 . Radiating patch has a combined geometry realized by a half-circular ring and half-square ring. To achieve a proper impedance matching and increased bandwidth with (Voltage standing wave ratio) VSWR ≤ 2, the study made use of an L-shaped element which was connected to the ground; moreover, the researchers added a split-ring resonator onto the ground to obtain one notched band. The comparison of the proposed antenna performance with previously presented UWB monopole antennas, was performed by using Analytic Hierarchy Process (AHP) method. A good agreement was observed between simulated and experimental results. .