GHz Wireless Local Area Network Research Articles

AN ULTRA-COMPACT DUAL-BAND ANTENNA WITH TUNING ARMS FOR WLAN APPLICATIONS

An ultra-compact dual-band printed antenna is proposed. Connective and concentric double split rings (CCDSR) are used to generate two resonant frequencies in wireless local area network (WLAN) frequency bands. Tuning arms are added to the microstrip fed line, which can be used to tune the upper frequency band. The dimension of this antenna is only 9 £ 24 £ 1mm 3 , much smaller than those reported antennas. The measured i10dB bandwidth in the 2.44GHz band is 140MHz (2.37{2.51GHz) and in 5.34GHz is 1.23GHz (4.86{6.09GHz), covering the 2.4/5.2/5.8GHz WLAN operating bands. Good radiations at these bands are also observed.

Band-notched design of the planar monopole antenna for WLAN/WiMAX applications

A simple printed monopole antenna with tunable slots is proposed for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications.The antenna structure consists of a semicircular ground and a rectangular patch with four round corners. By etching a couple of slots in the patch, the notched band from 3.7 to 4.8 GHz can be obtained. Furthermore, by adjusting the length and position of the slot, we make the notched band tunable both the center frequency and bandwidth. The proposed antenna is successfully designed and measured. The measured 10 dB bandwidth for return loss covers both the 2.4/5.2/5.8 GHz WLAN bands and 2.5/3.5/5.5 GHz WiMAX bands. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2782–2786, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25593

Numerical and Experimental Analysis of Impedance Matched Inverted-L and Stair Inverted-L Antenna for 5 GHz WLAN Operation

This paper presents impedance matched high gain inverted-L antenna (ILA) and stair ILA for 5 GHz wireless local area network (WLAN) by means of numerical and experimental analysis. Numerical simulation is carried out using method of moments in Numerical Electromagnetic Code (NEC-2) and agilent vector network analyzer, watts antenna trainer, and microwave engineering trainer are used for the measurement. The experimental results show that ILA and stair ILA has 10-dB return loss bandwidth of 650 MHz (5170 - 5820 MHz) and 360 MHz (5320 - 5680 MHz) respectively covering the unlicensed national information infrastructure (U-NII) mid frequency bands for 5 GHz WLAN operation. Omnidirectional radiation patterns are achieved for both antennas in XY plane and the antennas have peak gain of 6.65 and 10.987 dBi respectively at center frequency (5.5 GHz) of antenna operating bandwidth. Moreover, the antennas have radiation efficiency of greater than 84% and 91% respectively within the return loss bandwidth.

Inkjet-Printed RF Structures on BST-Polymer Composites: An Application of a Monopole Antenna for 2.4 GHz Wireless Local Area Network Operation

In this study, 0–3 ceramic–polymer composite substrates are utilized in RF applications in combination with inkjet printing technology. The substrates were fabricated from barium–strontium–titanate and polyphenylene sulfide. The relative permittivity and loss tangent were measured by inkjet-printed silver transmission lines and resonant techniques. They increased from 3.2 to 14.2 and from 0.003 to 0.0055, respectively, at 5 GHz with increasing ceramic loading up to 36.4 vol%. An antenna for 2.4 GHz wireless local area network band was proposed. A return loss of >−15 dB and a total antenna efficiency of >60% were measured across the band.

Design of a dual‐band π‐shaped microstrip patch antenna with a shorting pin for 5.2/5.8 GHz WLAN systems

AbstractThis article describes the design, fabrication, and measurement of a novel π‐shaped dual‐band antenna with a shorting pin for 5.2/5.8 GHz wireless local area network (WLAN) systems.To obtain sufficient bandwidth when return loss (RL) < −10 dB, a shorting pin is inserted in the patch and a coaxial probe source is used. The measured result of the fabricated antenna provides 211 MHz bandwidth from 5.147 to 5.358 GHz and 114 MHz bandwidth from 5.712 to 5.826 GHz (RL < −10 dB) with the gain ranging from 5.73 to 6.52 dBi. Also, a good radiation pattern is achieved within the WLAN band (5.150–5.350 GHz and 5.725–5.825 GHz) range. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:825–827, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25049

A printed circular‐ring monopole antenna with band‐notched feature for UWB application

AbstractA printed circular‐ring monopole antenna with band‐notched feature for ultra‐wideband application has been presented and investigated. The band‐notched characteristic is achieved by attaching a C‐shaped short‐circuited stub. Experimental results show that the proposed antenna meets the requirement of wide‐working bandwidth of 3.1–10.6 GHz with voltage‐standing wave ratio <2, while avoiding the interference with the 5 GHz wireless local area network band. Transfer functions of the antenna systems are given experimentally, and the parametric studies are performed numerically in this article. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:827–830, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25050

Broadband dual‐frequency spider‐shaped printed dipole antenna for WLAN applications

AbstractA novel broadband dual‐frequency spider‐shaped dipole antenna for 2.4/5.2 GHz wireless local area networks (WLAN) is proposed. The antenna consists of a double‐sided printed dipole, whose long arms and short center‐stubs can produce dual bands and lead to good impedance matching in a wide dual‐band without external matching circuitry. For the experimental study, excellent performance for operating frequencies across 2240–3260 MHz and 4700–5970 MHz bands has been observed. Good radiation characteristics of dipole‐like patterns, and 2.6‐ and 4.6‐dBi peak antenna gains for the lower and upper bands, respectively, have been obtained. And this antenna could be easily printed and integrated on the system circuit board for WLAN applications. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:917–919, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25041

Triple broadband compact planar inverted F antenna for WLAN and WiMAX

This article proposes a novel antenna structure by slot loading method based on the planar inverted F antenna (PIFA), which is fed by coaxial probe. The antenna structure consists of a new and flexible slot array including five slots. To reveal the mechanism of slot loading in creating new and broad frequency band, the article discusses the performance of the five slots in detail. Simulations with Ansoft HFSS 10.0 indicate that the −10 dB relative impedance bandwidth can reach 17.2 %, 8.9 % and 12.1 % that covers 2.40/3.30/5.15/5.725 GHz wireless local area network (WLAN) and world interoperability for microwave access (WiMAX) bands. Meanwhile, the antenna has stable radiation pattern, high gain and low profile. Especially, the slot array is flexible and capable of being realized in various application cases. Actually the design reaches broadband, multi-band, miniaturization, high gain and is easy to fabricate.

A novel compact dual‐band bandpass filter using spiral‐shaped microstrip resonators

AbstractIn this letter, a dual‐band bandpass filter is proposed by consisting of spiral‐shaped microstrip resonators. Meanwhile, a skew‐symmetric tapped feed structure is applied to introduce two transmission zeros on both sides of individual passbands, and thereby improve the filter selectivity. The measured results of the designed third‐order dual‐band bandpass filter for 2.4/5.2 GHz wireless local area network applications are in good agreement with the simulated predictions. Moreover, the filter has a size reduction of 40%, as compared with the conventional square open‐loop bandpass filters. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 543–547, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24965

DUAL-WIDEBAND SYMMETRICAL G-SHAPED SLOTTED MONOPOLE ANTENNA FOR WLAN/WIMAX APPLICATIONS

A novel dual-wideband printed monopole antenna is proposed for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. The proposed antenna consists of a T-shaped monopole on top and dual combined G-shaped slots etched symmetrically on the ground plane to achieve a dual-wideband performance. Prototype of the proposed antenna has been constructed and tested. The measured 10dB bandwidths for return loss are 1.76GHz from 2.13 to 3.89GHz and 0.92GHz from 5.03 to 5.95GHz, covering all the 2.4/5.2/5.8GHz WLAN and 2.5/3.5/5.5GHz WiMAX bands. And this antenna also has omni-directional patterns over the lower operating range.

Balanced Dual-Band BPF using only Equal-Electric-Length SIRs for Common-Mode Suppression

This paper presents a new balanced dual-band bandpass filter (BPF) designed for 2.4/5.2 GHz wireless local area networks (WLANs). Because adopted in the BPF are only bi-section equal-electric-length stepped-impedance resonators (SIRs), whose dimensions can be determined using analytic formulas, the BPF can be easily and efficiently designed. The inner SIRs are designed to resonate only at the odd-mode resonant frequencies of the input and output SIRs but not at the even-mode ones. This leads to well-behaved differential-mode (DM) transmission and excellent common-mode (CM) suppression for the BPF. Simulated and measured results are found to agree quite well to each other. The measured minimum DM insertion losses in the two passbands are 2.1 and 2.54 dB, whereas the measured CM rejections are higher than 33 dB in the frequency range from 1 to 7 GHz.

DUAL-POLARIZED DIELECTRIC RESONATOR ANTENNA WITH HIGH ISOLATION USING HYBRID FEEDING MECHANISM FOR WLAN APPLICATIONS

A dual-feed dual-polarized dielectric resonator antenna (DRA) with high isolation is proposed in this paper. The high isolation is achieved by using two hybrid feeding mechanism: one port having an H-shaped aperture coupled feed and the other with two out-of- phase probe feeds. The antenna is designed to operate at around 5.2GHz for WLAN (Wireless Local Area Network) applications and experimental results show that it has more than 35dB isolation over the entire impedance bandwidth. Good symmetric broadside radiation patterns with low cross polarizations are observed in the two principal planes, and in addition, the front-to-back (F/B) ratios for Port 1 and Port 2 are 10 and 18dB, respectively.

Linearity enhanced 2.4 GHz WLAN HBT power amplifier using digitally-controlled tunable output matching network with pHEMT switch in GaAs BiFET technology

Presented is the linearity improvement technique of a power amplifier (PA) using a digitally-controlled tunable output matching network implemented in GaAs BiFET technology. The load impedance of the heterojunction bipolar transistor (HBT) power device in the last stage of the PA is adjustable in terms of output power levels by a metal-insulator-metal (MIM) capacitor array with pHEMT switches in the output matching network. A 2.4 GHz two-stage PA for IEEE 802.11g, Wireless Local Area Network (WLAN) application, is implemented to demonstrate the technique. Not only is the maximum linear output power of the PA increased by 2.5 dB, but the linearity is also improved by 4 dB at the output power of 15 dBm for the error vector magnitude specification of −28 dB.

A NOVEL RECTANGULAR SLOT ANTENNA WITH EMBEDDED SELF-SIMILAR T-SHAPED STRIPS FOR WLAN APPLICATIONS

A novel rectangular slot antenna with embedded self- similar strips is proposed for wireless local area network (WLAN) applications. The proposed antenna comprises a T-shaped monopole and inverted self-similar strips embedded in the rectangular slot etched on the ground plane. The measured results of the fabricated antenna show that the impedance bandwidths (VSWR < 2) are 180MHz from 2.36 to 2.54GHz and 920MHz from 5.05 to 5.97GHz, which cover all the 2.4/5.2/5.8GHz WLAN operating bands. And the radiation patterns are almost omni-directional in the azimuthal plane within the lower operating bands.

High-gain dual-polarised planar slot array for WLAN applications

A high-gain dual-polarised planar etched slot array for use in wireless local area networks (WLAN) is presented. Two sets of four collinear slots are used as radiators for each polarisation. Each set of four collinear slots is constructed as a centre-fed long slotline, with etched crossovers to split the slotline into four resonant and in-phase half-wavelength slots. A reflector etched on a separate substrate spaced a quarter-wavelength away from the slot array ensures unidirectional radiation. The final antenna achieved a gain of 14.5 dBi, a return loss better than 10 dB, and port isolation in excess of 30 dB over the 2.4–2.484 GHz WLAN frequency band.

WLAN 대역의 변형된 십자형 개구 결합 마이크로스트립 원형 편파 배열 안테나

본 논문은 충분한 대역폭과 이득을 갖는 5.8 GHz 대역의 무선 LAN용 십자형 개구 결합 마이크로스트립 원형 편파 <TEX>$2\times2$</TEX>배열 안테나를 설계 제작하였다. 설계한 안테나는 정사각형 패치를 사용하고 직렬 형태의 급전 선로위에 <TEX>$\lambda_g$</TEX>/4 위상차가 나는 곳에 슬롯이 위치하게 하여 전류 방향이 최대 최소가 반복되게 하여 원형 편파를 발생시키게 된다. 기존의 십자형 슬롯 안테나 구조를 수정하여 두 개의 슬롯이 직각으로 교차하는 부분을 없애고 분리된 4개의 슬롯으로 안테나를 설계함으로써 후방 방사를 줄이고 배열을 통해 안테나의 지향성도 개선할 수 있다. 측정된 <TEX>$2\times2$</TEX> 배열 안테나의 대역폭은 5.67~5.95 GHz로 나타났으며, 최대 방사 이득은 10.59 dBi를 얻었다. In this paper, cross-aperture coupled microstrip circular polarization antenna is proposed for 5.8 GHz WLAN(Wireless Local Area Network). A single antenna consists of square patch and slots are located in series feed line with <TEX>$\lambda_g$</TEX>/4 phase different which make current direction maximum and minimum repeatedly to generate RHCP(Right Handed Circularly Polarization). We are proposed new structure that removed the section which intersected at a right angle and were composed to four separated slots. The proposed cross slots reduce back lobe of radiation pattern and improve antenna gain. Impedance bandwidth of the manufactured <TEX>$2\times2$</TEX> array antenna is from 5.67 to 5.95 GHz and the maximum radiation gain is 10.59 dBi.

A modified CPW‐fed monopole antenna with very small ground for multiband WLAN applications

AbstractA modified planar monopole antenna with multiband operation for wireless local area networks (WLAN) is presented in this article. The antenna is composed of symmetrical hook‐shaped strips and a horizontal strip on the top, both printed on an inexpensive FR4 substrate, and is fed by a coplanar waveguide (CPW) feedline. The measured results explore broadband dual‐frequency operation with 2:1 VSWR impedance bandwidths range from 2.07 to 2.52 GHz and 5.07 to 6.62 GHz, which cover the 2.4/5.2/5.8 GHz WLAN operating bands. Also, good similar omnidirectional radiation patterns have been achieved. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 463–466, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24940

A Microstrip Fed Patch Antenna with Two Parasitic Invert L Stubs for Dual-Band WLAN Applications

A novel microstrip fed dual-band design patch antenna with two parasitic invert L stubs for 2.4/5- GHz wireless applications is presented in this paper. Printed on a dielectric substrate of FR4 with relative permittivity of 4.4 and thickness of 1 mm, and fed by a 50? microstrip line, the patch antenna with two parasitic invert L stubs is demonstrated to generate three resonant modes to cover 2.4/5.2/5.8- GHz wireless local area network (WLAN) bands with satisfactory radiation characteristics. Experimental and simulated S parameters are presented. Parameters sweep and simulated radiation patterns are demonstrated.

Experimental investigations of 60 GHz WLAN systems in office environment

This paper presents the results of an experimental investigation of 60 GHz wireless local area network (WLAN) systems in an office environment. The measurement setup with highly directional mechanically steerable antennas and 800 MHz bandwidth was developed and experiments were performed for conference room and cubicle environments. Measurement results demonstrate that the 60 GHz propagation channel is quasioptical in nature and received signal power is obtained through line of sight (LOS) and reflected signal paths of the first and second orders. The 60 GHz WLAN system prototype using steerable directional antennas with 18 dB gain was able to achieve about 30 dB baseband SNR for LOS transmission, about 15-20 dB for communications through the first-order reflected path, and 2-6 dB SNR when using second-order reflection for the office environments. The intra cluster statistical parameters of the propagation channel were evaluated and a statistical model for reflected clusters is proposed. Experimental results demonstrating strong polarization impact on the characteristics of the propagation channel are presented. Cross-polarization discrimination (XPD) of the propagation channel was estimated as approximately 20 dB for LOS transmission and 10-20 dB for NLOS reflected paths.

Optimization of band-notched UWB antenna using micro-genetic algorithm combined with FDTD

The micro-genetic algorithm (MGA) optimization combined with the finite-difference time-domain (FDTD) method is applied to design a band-notched ultra wide-band (UWB) antenna. A U-type slot on a stepped U-type UWB monopole is used to obtain the band-notched characteristic for 5 GHz wireless local area network (WLAN) band. The measured results show that voltage standing wave ration (VSWR) less than 2 covers 3.1–10.6 GHz operating band and VSWR more than 2 is within 5.150–5.825 GHz notched one with the highest value of 5.6. Agreement among the calculated, HFSS simulated and measured results validates the effectiveness of this MGA-FDTD method, which is efficient for UWB antennas design.