inverted-L Strip Research Articles

Tri-Band Bidirectional Antenna for 2.4/5 GHz WLAN and Ku-Band Applications

A compact tri-band, low profile, and lightweight antenna is proposed for 2.4/5 GHz WLAN and Ku-band applications. The antenna geometry was a radiating rectangular patch surrounded by a wide circular slot with an inverted-L strip connected to one side of the slot. It was mounted on a copper layer of a single side FR4 substrate with a dielectric constant of 4.3 and a height of 1.6 mm. It was fed by a 50-Ω coplanar waveguide. This design was very compact (40 × 40 × 1.6 mm3). Simulated and actual measurements of an antenna setup in the laboratory verified that the antenna’s bidirectional radiation pattern completely covered the three transmission bands: 2.4–2.485 GHz, 5.15–5.825 GHz and 13.4–17.7 GHz with less than 10-dB return loss and maximum gains of 2.35 dBi, 4.41 dBi and 4.71 dBi, respectively. Wireless communication for the self-navigated vehicle, for one example, is fully supported by this single antenna.

Self-Oscillating Circularly Polarized Active Integrated Monopole Antenna Using Cross-Coupled Pair and Inverted-L Strip

A self-oscillating active integrated antenna (AIA) featuring circular polarization (CP) is presented in this letter. The oscillation is sourced by a cross-coupled pair (XCP) with negative conductance. Microstrip lines with embedded LC resonators are applied to fulfill the feedback loop between the pair of transistors, which functions as the frequency selective element with harmonic suppression capability. A monopole antenna is attached to the output of the XCP for radiating the oscillation power into space; the CP operation, meanwhile, is obtained by introducing a perturbation using an inverted-L strip protruding from the ground plane. A left-handed circularly polarized AIA (CPAIA) was designed at 916 MHz as a potential far-field wireless power charging source in the ultrahigh-frequency ISM (industrial, scientific, medical) band. The experimental validation reveals that, when compared with existing CPAIA designs, the proposed work consumes much less dc power but still keeps acceptable radiation parameters; it also features the smallest size and highest dc-to-RF conversion efficiency. The lowpower consumption makes the direct integration with a small-size solar panel become feasible.

Asymmetric CPW Fed Miniaturized dual polarized monopole Antenna for WLAN/WiMAX Applications

An Asymmetric coplanar waveguide (CPW) Fed Miniaturized dual polarized (linear Polarized and Circularly Polarized) monopole Antenna Implemented. The Inverted-L Strip monopole antenna and the asymmetric ground plane for WLAN/Wi MAX applications are presented. Monopole antenna mainly icludes asymmetric ground plane which are fed with Coplanar Wave inverted L-shape strip and a slit embedded on the ground plane providing an orthogonal phase difference were designed to generate CP radiation. Inverted-L shape strip resonance and matching condition are examined by high-frequency structure simulator (HFSS) and the prototype is designed and measured. The measure simulated results shows that the monopole antenna impedance band-width with at −10 dB of 92.5 %( 3.36-6.66GHz) and a 3-dB axial-ratio bandwidth of 53.9 %( 5.4 -6.39 GHz) could be completed which could absolutely cover the WLAN (5.725 GHz - 5.85 GHz) band. Meanwhile, a linear polarization is also bought which could absolutely cover the WiMAX (3.3 GHz -3.7 GHz) bands. Orthogonal phase difference and average peak gain for lower band 1.9 dB and upper band 2.48 dB have been achieved, respectively.

Wideband circularly polarized parasitic patches loaded coplanar waveguide-fed square slot antenna with grounded strips and slots for wireless communication systems

In this paper, the design, implementation, and experimental validation of a wideband circularly polarized square slot antenna (CPSSA) is presented. The proposed antenna comprises of an irregular square patch, asymmetrical grounded-L strips, an inverted-L grounded slot, a parasitic asymmetrical rectangular split ring resonator (RSRR) and inverted-L strip patches with the overall size of 0.305λL × 0.305λL × 0.007λL. By appropriately embedding strips, slots and parasitic patches on the antenna structure, the measured wideband 3-dB axial ratio bandwidth (ARBW) of 83.2% (2.33–5.65 GHz) is obtained, while the measured impedance bandwidth (IBW) of 86.72% (2.165–5.48 GHz) is achieved. Overall, CP bandwidth is 80.66%. A parametric study of different design parameters is investigated, and the overall performance of the antenna is presented.

Wideband Inverted-L Microstrip-via-Fed Circularly Polarized Antenna with Asymmetrical Ground for WLAN/Wimax Applications

Abstract A design with wideband and circularly polarized radiation antenna from an open-slot antenna has been demonstrated in this paper. The proposed antenna, which consists of an open slot and an inverted-L strip feeding, provides a large bandwidth, which completely cover the Wimax (3.3–3.8 GHz) and WLAN (2.4–2.48 GHz) bands. The open slot is formed by an modified ground plane with a slit cut and monofilar spiral stubs employed, which fed by an asymmetrical inverted-L strip feedline using a via. As demonstrated, the CP operation was significantly improved by loading monofilar spiral stubs connected to the asymmetric feedline by means of a via. A parametric study of the key parameters is made and the mechanism for circular polarization is described. After optimization, the impedance bandwidth is approximately 3.78 GHz (2.12 to 5.9 GHz) and the 3 dB axial ratio bandwidth is approximately 2.75 GHz (2.2 to 4.95 GHz), which represent fractional bandwidths of approximately 94.3 % and 76.9 %, respectively.

Dual‐band circularly polarised planar monopole antenna for WLAN/Wi‐Fi/Bluetooth/WiMAX applications

A novel planar monopole antenna with dual-band circularly polarisation (CP) is presented here. The antenna consists of a modified L-shaped monopole, an inverted-L strip, and a modified ground. The utilisation of the modified L-shaped monopole not only generates dual-band operation, but also excites CP radiation in the lower band. In order to achieve CP in the upper band, a parasitic inverted-L strip is added on the top plane of the substrate and a modified ground is designed. The proposed antenna has been fabricated and tested, the measured -10 dB reflection coefficient bandwidths are 370 MHz (2.38-2.85 GHz) in the lower band and 2330 MHz (4.05-6.38 GHz) in the upper band. The measured corresponding 3 dB axial ratio (AR) bandwidths are 610 MHz (2.39-3 GHz) and 850 MHz (5.15-6 GHz), respectively. The overlapped -10 dB reflection coefficient and AR bandwidths can totally cover the WLAN bands, Wi-Fi bands, Bluetooth band, and partly cover the WiMAX bands. The proposed antenna owns bidirectional radiation characteristic and reasonable gain at both the lower band and the upper band.

Miniaturized wideband dual linearly and circularly polarized printed square slot antenna for multiradio wireless systems

A dual symmetrical coplanar waveguide (CPW)-fed small size wideband printed square slot antenna (SSA) with dual linearly and circularly polarized radiation capability is presented. The antenna is composed using a square slot, two symmetrical orthogonal CPW feed lines connected to horizontal and vertical arm of L-shaped radiator, an embedded parasitic inverted-L strip at the lower left corner of the square ground slot and engraving slots in the ground plane. Circular polarization (CP) is achieved due to two orthogonal CPW feed lines and a common L-shaped radiator. Isolation between ports is improved by engraving slots at the lower left corner of ground plane and embedded parasitic inverted-L strip. The sense of dual-polarization can be changed in pass-band by changing the port excitation. Measured antenna reveals that an 84.4% (4.6 GHz, 3.15–7.75 GHz) −10 dB impedance bandwidth (IBW) and about 33% (2.03 GHz, 5.12–7.15 GHz) 3-dB axial ratio bandwidth (ARBW). Isolation between ports <−16 dB is achieved over usable CP band.

Miniaturised design of coplanar waveguide‐fed broadband circularly polarised slot antenna

A novel miniaturised design of broadband circularly polarised (CP) antenna using a coplanar waveguide feed is presented. To realise CP characteristic, a pair of inverted-L strips around two opposite corners of the slot is protruded. By properly folding the modified ground plane, the 3-dB axial-ratio (AR) band is shifted to around a lower-frequency location, whereas the input impedance band is shifted downwards through the Y-shaped loading strip. The overall size of the antenna is about 0.34 λ 0 × 0.34 λ 0 × 0.009 λ 0 at 1.7 GHz. Measured results show that the proposed design can deliver 3-dB AR bandwidth of 36.8% (1.55–2.25 GHz) and 10 dB impedance bandwidth of 63.2% (1.17–2.25 GHz).

A low-loss dielectric using CaTiO&lt;sub&gt;3&lt;/sub&gt;-modified Mg&lt;sub&gt;1.8&lt;/sub&gt;Ti&lt;sub&gt;1.1&lt;/sub&gt;O&lt;sub&gt;4&lt;/sub&gt; ceramics for applications in dielectric resonator antenna

The microwave dielectric properties of (1-x)Mg <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1.8</sub> Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1.1</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> -xCaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ceramics prepared by the mixed oxide route have been investigated. Spinel-structured Mg <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1.8</sub> Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1.1</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> , ilmenite-structured MgTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> and perovskite-structured CaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> were coexisted and the three-phases system was confined by X-ray diffraction patterns, EDX analysis and it also leads to near-zero τf. The microstructures of the ceramics were characterized by SEM. The microwave dielectric properties of the ceramics can be effectively controlled by varying the x value. For practical applications, a fine combination of microwave dielectric properties (ε <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> ~ 19.61, Q×f~ 72,700 GHz at 9.03 GHz, τ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> ~ -3.7 ppm/°C) was achieved for 0.91Mg <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1.8</sub> Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1.1</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> -0.09CaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ceramics sintered at 1330°C for 4 h, which makes it is a very promising candidate material for applications in dielectric resonator antenna. A new triple-band dielectric resonator antenna fed by a coplanar waveguide is presented. The proposed antenna, composed of a high permittivity dielectric resonator and printed on FR4 substrate, is fed by a 50 Ω coplanar waveguide transmission line. In order to achieve wideband applications, the antenna with two parasitic inverted-L strip is demonstrated to generate two resonant frequencies covering 3.5 and 5.2 GHz. The measured results show that the antenna covers the frequency bands 2.30-2.72, 3.45-3.61, and 5.05-6.23 GHz with less than -10 dB of S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> . The frequency response of the simulation results shows good agreement with the measured data. Good antenna gain, radiation efficiency and radiation patterns of the proposed antenna have also been observed across the operation band. Details of the proposed antenna design and experimental results are presented and discussed.

Miniaturized CPW-Fed Triband Antenna with Asymmetric Ring for WLAN/WiMAX Applications

A compact CPW-fed triband slot antenna for WLAN/WiMAX applications is proposed. The proposed antenna is formed by an asymmetric ring, an inverted L-strip, and a straight strip. By employing these structures, the antenna can generate three operation bands with compact size and simple structure. The measured and simulated results show the presented antenna has impedance bandwidths of 100 MHz (2.39–2.49 GHz), 360 MHz (3.36–3.72 GHz), and 760 MHz (5.13–5.89 GHz), which covers both WLAN in the 2.4/5.2 GHz bands and WiMAX in the 3.5/5.5 GHz bands. The antenna is successfully simulated and measured, showing triple bands can be obtained by using three different radiators and also indicating that the proposed antenna is suitable for the WiMAX/WLAN applications.

Coplanar Waveguide Fed Compact Wide Circular-Slotted Antenna for Wi-Fi/WiMAX Applications

A coplanar waveguide (CPW) fed printing and wide circular slotted, dual band antenna for Wi-Fi/WiMAX applications are presented. The antenna mainly encompasses a ground with a wide circular slot in the centre, a rectangular feeding strip, and two pairs of symmetric planar invertedL(SPIL) strips connecting with the slotted ground. The tuning effects of the rectangular patch, ground size, and SPIL strips to the resonance and matching condition are examined by HFSS and the prototype is fabricated and measured. The simulation and experimental results show that the antenna has an impedance bandwidth with −10 dB reflection coefficients 600 MHz (3.26–3.86 GHz, lower band) and 1040 MHz (5.02–6.26 GHz, upper band), which can cover both the Wi-Fi 5.2/5.5/5.8 GHz and WiMAX 3.3/3.5/3.7/5.8 GHz bands. Moreover, a stable omnidirectional radiation pattern and average peak gain for lower band 3.23 dB and upper band 5.93 dB have been achieved, respectively.

A COMPACT CPW-FED MONOPOLE ANTENNA WITH TRIPLE BANDS FOR WLAN/WIMAX APPLICATIONS

A novel compact coplanar waveguide (CPW)-fed printed antenna with triple bands for WLAN and WiMAX applications is presented. By using a parasitic circular patch, a pair of symmetrical inverted-L strips and a 50-› transformer, the antenna can efiectively provide a good input impedance matching. The tuning efiects of the ground size, the parasitic circular patch and the symmetrical inverted- L strips to the resonance and matching condition are then examined, and the prototype of the proposed antenna is further fabricated and measured. The experimental and numerical results exhibit that the antenna has impedance bandwidth with 10dB return loss 2.32{ 2.80GHz, 3.06{4.13GHz and 5.03{6.04GHz, which can cover both the WLAN 2.4/5.2/5.8GHz bands and the WiMAX 2.5/3.5/5.5GHz bands. Also, a stable monopole-like radiation pattern and an average antenna gain of 3.06dBi across the operating bands have been obtained.

A COMPACT MICROSTRIP SLOT ANTENNA WITH A PAIR OF INVERTED L-STRIPS AND ELLIPTICAL-ARC-SHAPED STUB FOR WLAN/WIMAX APPLICATIONS

A novel compact microstrip slot antenna applied to WLAN/WiMAX applications is presented. The proposed antenna consists of a trapezoid and ellipse slot, a pair of symmetrical inverted L-strips, an elliptical-arc-shaped stub and a monopole radiator. By adjusting the dimensions and positions of these structures, the antenna can efiectively generate three difierent resonances to cover the WLAN/WiMAX bands while maintaining small size and simple structure. Based on this concept, a prototype of the proposed antenna has been successfully fabricated and measured. The experimental and numerical results show that the antenna has impedance bandwidth with 10dB return loss of 360MHz (2.33{2.69GHz) and 2630MHz (3.24{5.87GHz), which can cover both the WLAN 2.4/5.2/5.8GHz bands and the WiMAX 2.5/3.5/5.5GHz bands. In addition, good monopole-like radiation characteristics with su-cient antenna gains are obtained over the operating bands.

Rectangular Ring Open-Ended Monopole Antenna with Inverted L-Strip for WLAN Dual-Band Operations

A novel design for a simple rectangular ring with open-ended monopole antenna wireless local area network (WLAN) applications is proposed in this article. The proposed antenna consists of an open-ended rectangular ring, an inverted L-strip, and a rectangular slit in the ground plane, and is fed by a 50 <TEX>${\Omega}$</TEX> microstrip feed-line. Prototypes of the proposed antenna were designed, fabricated, and tested. Experimental results show that the proposed antenna receives 2.3125-2.775 GHz and 4.8625-6.7125 GHz with a return loss less than -10 dB, covering the required bandwidths of the 2.4/5.2/5.8 GHz WLAN standards. Meanwhile, the 2D radiation patterns and 3D gain performance of the antenna in the operation bands were also observed and discussed.

Design of a compact broadband circularly-polarized slot antenna for wireless applications

This article presents design of a compact broadband circularly-polarized square slot antenna with a coplanar waveguide feed.A circular polarization bandwidth larger than 64.7% (3172-6211 MHz) obtained with the proposed antenna by embedding two inverted-L grounded strips and a 45° bended strip around corners, whereas the impedance bandwidth can be greatly improved through the tuning stubs. 3 dB axial ratio bandwidth of the proposed CP antenna is large as 64.7% in a frequency band of 3172-6211 MHz. The CP antenna operates in a frequency range from 2.25 to 6.75 GHz and 8.25 to 10.25 GHz with VSWR < 2 impedance bandwidth. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:413-418, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27303

Compact CPW-Fed Tri-Band Printed Antenna With Meandering Split-Ring Slot for WLAN/WiMAX Applications

A novel compact tri-band printed antenna for WLAN and WiMAX applications is presented. The proposed antenna consists of a modified rectangular slot, a pair of symmetrical inverted-L strips, and a Y-shaped monopole radiator with a meandering split-ring slot. Tuning the locations and the sizes of these structures, three distinct current paths can be produced at three independent frequency bands, respectively. Based on this concept, a prototype of the tri-band antenna is further fabricated and measured. The experimental and numerical results show that the antenna has impedance bandwidth (for return loss less than 10 dB) of 430 MHz (2.33-2.76 GHz), 730 MHz (3.05-3.88 GHz), and 310 MHz (5.57-5.88 GHz), which can cover both the WLAN 2.4/5.8-GHz bands and the WiMAX 2.5/3.5-GHz bands.

Broadband CPW-Fed Circularly Polarized Square Slot Antenna With Inverted-L Strips for UWB Applications

This letter presents a new design for a circularly polarized square slot antenna (CPSSA). The proposed single-layer antenna composed of a square ground plane embedded with two unequal-size inverted-L strips around two opposite corners is capable of generating a resonant mode for exciting two orthogonal E vectors. In this model, compared to the previous CPSSA structures, the impedance bandwidth and the axial ratio bandwidth of antenna are increased, which is four times wider than the impedance bandwidth of previous similar designs. The designed CPSS antenna with size 60 × 60 × 0.8 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> operates over the frequency band between 2.67 and 13 GHz (4.74:1, 132%) for VSWR <; 2, exhibiting a 32.2% (4.9-6.9 GHz, 1.5:1) circular polarization (CP) bandwidth. Throughout this letter, the improvement process of the axial ratio (AR) and S\\ properties are presented and discussed in detail.

OCTA-BAND LV-SHAPE CPW-FED MONOPOLE ANTENNA

A novel octa-band LV-shape printed monopole antenna fed by a coplanar waveguide (CPW), using two inverted-L strips and a LV-shape radiating stub is proposed and investigated. The proposed antenna has a simple planar structure and occupies area of 30 × 35 mm2 on the system circuit board of the portable communication devices. The simulated and measured octa-band monopole antenna frequencies cover the GSM850/900/1800/1900/DCS/PCS/UMTS and WLAN (2.4 GHz, 5.2 GHz and 5.8 GHz) band operations for S 11 ≤ – 10 dB. The measured peak gains are 3, 2.33, 5, and 3.3 dBi with sufficient bandwidths to cover modern portable communication devices. The simulated and measured results show a good agreement. This proposed antenna with multiband, broadband matched impedance, stable radiation patterns, constant antenna gains and compact size is suitable for multi-mode applications.

A Novel Compact CPW-fed Antenna with Multi-resonance Mode

A multi-resonance antenna for wireless communications is reported. By using double inverted-L strips, the antenna demonstrated compact size (15 mm <TEX>${\times}$</TEX> 14 mm) including the ground, multi-band operation for IEEE 802.11 a/b/g/p applications, and wide bandwidth of 1.7 GHz at 5 GHz band. Good radiation features of omni-directional patterns and 1.98 and 2.29 dBi peak antenna gains for the lower and upper bands, respectively, have been achieved.

Wideband Low-Profile Printed Inverted-L Antenna in Mobile Phones for WLAN/WiMAX Application

This letter presents a low-profile printed monopole wideband antenna for mobile terminals. The proposed antenna is simply structured with an inverted-L strip, which occupies the small area of 3 × 18 × 0.8mm3 (0.023λL × 0.138λL × 0.006λL at lower frequency edge of 2.3GHz) on a substrate which is perpendicular to the circuit board of the terminal. The height of the upright substrate is only 3mm (3.8mm including the circuit board). The proposed antenna achieves a 10-dB impedance bandwidth of 59.7% ranging from 2.16GHz to 4GHz, which can cover which can cover the 2.4GHz WLAN (2.4-2.4835GHz) and WiMAX (2.3-2.4/2.495-2.69/3.4-3.6GHz) operational bands. It is suitable for application to a multiband mobile phone due to its relatively low profile.