Small Monopole Antenna Research Articles

Tri-band small monopole antenna based on SRR units

In this paper a novel design for a tri-band monopole antenna coupled with metamaterial units is introduced. The proposed antenna was designed to cover WiMAX (2.5, 3.5) and WLAN (5.2) bands. In our proposal, a coplanar waveguide (CPW) fed circular-disk monopole antenna is coupled with three split ring resonator (SRR) units which exist on its back side. In our design a monopole antenna and SRR units are designed first to resonate at 5.2GHz and 2.5GHz respectively. In addition, antenna is loaded with post to force resonance at 3.5GHz. SRR units are used for 2.5GHz resonance to miniaturize antenna size, and our proposed antenna considered an electrically small antenna (ESA) at its first resonance frequency. Simulated and measured results exhibit a good agreement that validate our design.

Extremely small monopole antenna for wideband applications

A planar, extremely small wideband monopole antenna is proposed. The proposed antenna consists of a rectangular radiating patch with a star-shaped slot and a plus-shaped conductor-backed plane, which provides a wide usable fractional bandwidth of 122% (5.25–21.61 GHz). Using a plus-shaped conductor-backed plane, band-notched characteristics with notch frequency band at 6.95–8.22 GHz is obtained. The designed antenna is compact and of small size (10 × 13 × 1.6 mm3) with a 50 Ω feed line and offers a very simple geometry suitable for low cost fabrication and straightforward printed circuit board integration. Measured and simulated reflection coefficient curves are provided. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:617–621, 2015

Bandwidth Enhancement Technique of the Meandered Monopole Antenna

A small dual-band monopole antenna with coplanar waveguide (CPW) feeding structure is presented in this paper. The antenna is composed of a meandered monopole, an extended conductor tail, and an asymmetrical ground plane. Tuning geometrical structure of the ground plane excites an additional resonant frequency band and thus enhances the impedance bandwidth of the meandered monopole antenna. Unlike the conventional monopole antenna, the new resonant mode is excited by a slot trace of the CPW transmission line. The radiation performance of the slot mode is as similar as that of the monopole. The parametrical effect of the size of the one-side ground plane on impedance matching condition has been derived by the simulation. The measured impedance bandwidths, which are defined by the reflection coefficient of −6 dB, are 186 MHz (863–1049 MHz, 19.4%) at the lower resonant band and 1320 MHz (1490–2810 MHz, 61.3%) at the upper band. From the results of the reflection coefficients of the proposed monopole antenna, the operated bandwidths of the commercial wireless communication systems, such as GSM 900, DCS, IMT-2000, UMTS, WLAN, LTE 2300, and LTE 2500, are covered for uses.

Circular microstrip antenna with dual band‐stop performance for ultrawideband systems

ABSTRACTIn this article, a novel small monopole antenna with dual band‐notched characteristic for ultrawideband applications is proposed. The proposed antenna consists of circular‐disc radiating patch with a rotated T‐shaped slit, a feed line with a rotated Ω‐shaped split‐ring resonator, and a ground plane. The designed antenna has a small size. The simulated and measured results show that the antenna design exhibits an operating bandwidth (VSWR < 2) from 2.86 to 12.92 GHz with 3.3–4.2 and 5–6 GHz rejected bands covering all the 5.2/5.8 GHz wireless local area network, 3.5/5.5 GHz worldwide interoperability microwave access, and 4 GHz C bands. Good antenna gain and radiation pattern characteristics are obtained in the frequency band of interest. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2095–2098, 2014

Receiving and Detection of Ultra-Wideband Microwave Signals Radiated by Pulsed Excitation of Monopole Antennas

Pulsed excitation of small size monopole antennas for generating wideband electromagnetic pulses was used. The monopoles were excited by electrical pulses having rise times of 600 ps, 200 ps, 70 ps and voltages 100 V, 15 V, and 0.4 V respectively. Antennas spanning (0.3 – 26) GHz bandwidth, including broadband horns with coaxial outputs, were employed to receive signals, which were investigated using (0 – 26) GHz passband sampling oscilloscope. It was found that waveforms of signals, received by the antennas, mostly depend on the pulse rise time and on the details of geometry of monopoles. The electromagnetic pulses have relatively long duration of about 30 ns and spectral harmonics up to 22 GHz. Therefore they can be attributed to pulses with large base. The results show that the upper frequencies of the spectrum most probably are cut off by existing arrangement. Usage of such pulses can find wide practical application when they are received after transmission trough different media by a number of antennas having different operational frequency ranges, followed by digital signal processing. DOI: http://dx.doi.org/10.5755/j01.ms.20.2.6330

A dual-band monopole antenna for UHF-band applications

A dual-band monopole antenna for UHF-band applications has been demonstrated in this work. The dual-band characteristics are achieved using several strip monopole radiators. In addition, a small planar inverted-F monopole antenna is connected to the ground plane. The bandwidth improvement for the antenna is obtained mainly by modifying the geometrical configuration of the strip monopoles added at the antenna and the ground plane. The measured results of the impedance-bandwidth are about 44 MHz (458–502 MHz) and 118 MHz (701–819 MHz). © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:896–900, 2014

EFFICIENT ISOLATION BETWEEN ELECTRICALLY SMALL METAMATERIAL-INSPIRED MONOPOLE ANTENNAS

In this paper, a new electrically small metamaterial-inspired monopole antenna is presented. It consists of a simple square-shaped coplanar waveguide (CPW-fed) monopole with an embedded complementary split ring resonator (CSRR). It operates at three distinct frequency ranges around 2.45, 4.2, and 5.8 GHz, with low return loss and uniform radiation patterns, making it a perfect candidate for modern wireless applications. Furthermore, using this as a primary unit to construct two different 2 × 2 MIMO configurations, we achieve systematic minimization of mutual coupling, using additional single negative (SNG) metamaterial-inspired resonators. Mutual coupling is reduced by as much as 27 dB at the frequency of interest. Simulated and measured results of all antennas are in good agreement.

A Compact Ultrawideband Diversity Antenna With High Isolation

A compact ultrawideband (UWB) polarization diversity antenna with high isolation is designed in this letter. It comprises a step-tapered slot antenna (S-TSA) and a small square monopole antenna with an inverted H-shaped slot and an H-shaped conductor-backed plane. The isolation between the two ports is improved due to the orthogonality of E-field of two elements. The designed antenna has a small size of 26 × 38 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The measured results show that it can operate from 3.1 to 10.6 GHz, in which the average isolation is better than 30 dB.

Dual Band-Notched Small Monopole Antenna with Enhanced Bandwidth for UWB Applications

This article proposes a novel printed monopole antenna for ultra wideband applications with dual band-notch function. The antenna consists of a disc-shaped radiating patch with a pair of folded str...

Determination of Antenna Q from the Reflection-Coefficient Data [Antenna Designer's Notebook

Equivalent circuits containing frequency-variable radiation resistances are postulated for small monopole and small loop antennas above a ground plane. The equivalent circuits are valid below the first natural resonance frequency. By adding an external series inductance or a parallel capacitance, the antenna's Q is evaluated with the use of an invariant form for the reflection coefficient. The antenna's Q obtained this way accurately predicts the maximum obtainable bandwidth for either a single- or double-tuned matched antenna. At frequencies above the first resonance, the Q is evaluated by approximating the impedance or the reflection coefficient with polynomials within a narrow frequency range.

Extremely Small Two-Element Monopole Antenna for HF Band Applications

This paper presents a novel antenna architecture to achieve an extremely small form factor for HF band applications. The approach is based on manipulating the topology of a short monopole antenna without utilizing a high index material. A new architecture incorporating two radiating elements is configured, which allows significant gain enhancement. It is shown that such architecture can render a miniaturized HF antenna on air substrate having lateral and height dimensions as small as 0.0115λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.0115λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.0038λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> (150 mm× mm × 50 mm for operation at 22.9 MHz). It is found that the measured gain of such architecture can be as high as - 18.1 dBi, which is 16.7 dB higher than a reference inverted-F antenna realized on a high index material (ε <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> = 10.2) having exactly the same dimensions. The proposed antenna architecture is composed of two in-phase radiating vertical elements connected to two inductors between which a capacitive top load is connected to achieve the desired resonant condition. The two vertical elements act effectively as a monopole having increased height. It is also shown that the gain of the antenna can be increased monotonically by increasing the quality factor ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> ) of the phase shifter. High <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> air-core inductors that can be accommodated in electrically small monopole antenna are designed and incorporated in the phase shifter to achieve a gain value of - 17.9 dBi. Details about the proposed design approach, simulation, and measurement results are discussed.

Multiband monopole antenna with complementary split‐ring resonators for WLAN and WiMAX applications

Presented is an electrically small multiband monopole antenna based on complementary split-ring resonators, which are used to reduce antenna size. The antenna is fed by a three-stage microstrip line and provides 13, 17 and 16% impedance bandwidth performance covering the 3.5 GHz WiMAX and 2.4/5.2 GHz WLAN bands. Also, the proposed antenna exhibits almost an omnidirectional radiation pattern in the H-plane and a dipole-like radiation pattern in the E-plane. The return loss and radiation pattern measurements of the fabricated antenna are in very good agreement with simulation results.

Small monopole antenna with multiresonance characteristic by using rotated T-shaped slit and parasitic structure for UWB systems

In this letter, we present a new design of small-sized, low-profile, and multiresonance monopole antenna for ultrawideband applications.The proposed antenna consists of a square radiating patch and a ground plane with rotated T-shaped slit and conductor-backed plane, which provides a wide usable fractional bandwidth of more than 130% (3.05–15.27 GHz). By cutting a rotated T-shaped slit on the ground plane and also by inserting rotated T-shaped parasitic structure, additional resonances are excited and hence much wider impedance bandwidth can be produced, especially at the higher band. The designed antenna has a small size. Simulated and experimental results obtained for the proposed antenna is suitable for UWB applications. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:482–485, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27358

A novel design of reconfigurable small monopole antenna with switchable band notch and multi‐resonance functions for UWB applications

AbstractA novel reconfigurable square monopole antenna with switchable band‐notch and multiresonance performances is designed and manufactured.In the proposed structure, by cutting an inverted Γ‐shaped slit with variable dimension on the ground plane, new additional resonance is excited and hence much wider impedance bandwidth can be produced, especially at the higher band. Additionally, to generate multiresonance characteristics, we use an inverted U‐ring shaped slot, in the ground plane. To achieve reconfigurable function, we use a pin diode across the inverted U‐ring slot in the ground plane. When this pin diode is biased, the inverted U‐ring slot has converted to a rectangular slot with an E‐shaped strip protruded inside the slot, and also by creating this new structure, band notched performance is generated. The designed antenna has a small size of 12 × 18 mm2 while showing the radiation performance in the frequency band of 3.02 to over 12.97 GHz with a band rejection performance in the frequency band of 5.03–5.98 GHz. Simulated and experimental results obtained for this antenna with a reconfigurable frequency function in the range of 5 GHz–6 GHz show that it exhibits good radiation behavior within the UWB frequency range. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:652–656, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27376

Dual band‐notched small monopole antenna with novel W‐shaped conductor backed‐plane and novel T‐shaped slot for UWB applications

In this study, a novel method for designing a new monopole antenna with dual band-notched characteristic for UWB applications has been presented. The proposed antenna consists of a square radiating patch with a modified T-shaped slot, and a ground plane with two E-shaped slots and a W-shaped conductor backed-plane. By cutting two E-shaped slots in the ground plane, additional resonance is excited and hence much wider impedance bandwidth can be produced, especially at the higher band, which results in a wide usable fractional bandwidth of more than 130% (2.73%13.3 GHz). In order to generate single band-notched characteristic, the authors use a W-shaped conductor backed-plane structure on the other side of the substrate. In addition, by cutting a modified T-shaped slot in the radiating patch and microstrip feed-line, a dual band-notched function is achieved. The measured results reveal that the presented dual notch band monopole antenna offers a very wide bandwidth with two notched bands, covering all the 5.2/5.8 GHz wireless local area network, 3.5/5.5 GHz WiMAX and 4 GHz C bands. The designed antenna has a small size of 12 % 18 mm 2 . Good voltage standing wave ratio (VSWR) and radiation pattern characteristics are obtained in the frequency band of interest. Simulated and measured results are presented to validate the usefulness of the proposed antenna structure for ultra-wideband (UWB) applications.

Dual Band-Notched Small Monopole Antenna With Novel Coupled Inverted U-Ring Strip and Novel Fork-Shaped Slit for UWB Applications

This letter proposes a novel, small, printed monopole antenna for ultrawideband (UWB) applications with dual band-notch function. By cutting an inverted fork-shaped slit in the ground plane, additional resonance is excited, and hence much wider impedance bandwidth can be produced. To generate dual band-notch characteristics, we use a coupled inverted U-ring strip in the radiating patch. The measured results reveal that the presented dual band-notch monopole antenna offers a wide bandwidth with two notched bands, covering all the 5.2/5.8-GHz WLAN, 3.5/5.5-GHz WiMAX, and 4-GHz C-bands. The proposed antenna has a small size of 12 × 18 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> or about 0.15 λ × 0.25 λ at 4.2 GHz (first resonance frequency), which has a size reduction of 28% with respect to the previous similar antenna. Simulated and measured results are presented to validate the usefulness of the proposed antenna structure UWB applications.

Small monopole antenna with semicircular ground plane for UWB applications with variable band-notch structure

In this article a novel small microstrip monopole antenna with balloon-shape radiation patch and two circular ground structure in the back plane with variable band-notch structure is presented.Impedance bandwidth of the proposed antenna is approximately 153% with S11 <−10 dB in the frequency range of 3.2–23 GHz over an ultra-wideband frequency range with a variable center frequency band-notch from 5.1 GHz to 8.2 GHz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:12–14, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27255

Dual band-notch square monopole antenna with a modified ground plane for UWB applications

This paper presents a novel small square monopole antenna for UWB applications with dual band-notch function. By cutting an S-shaped slot in the ground plane, additional resonance is excited and hence, much wider impedance bandwidth can be produced, especially at the higher band that provides a wide usable fractional bandwidth of more than 120% (2.98–12.25 GHz). To generate a single frequency band-stop performance, we add a pair of C-shaped parasitic structures in the ground plane, and also in order to create the second notch frequency, we insert a horizontal rectangular strip in the center of two C-shaped parasitic structure in the ground plane. The measured results reveal that the presented dual band-notch monopole antenna offers a wide bandwidth with two notched bands, covering all the 5.2/5.8 GHz wireless local area network, 3.5/5.5 GHz WiMAX, and 4 GHz C bands. Good and radiation behavior within the UWB frequency range have also been obtained. The antenna has a small dimension of 12 × 18 mm2. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2743–2747, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27209

A new design of small square monopole antenna with enhanced bandwidth by using cross‐shaped slot and conductor‐backed plane

AbstractWe present a novel printed monopole antenna for ultrawideband applications. The proposed antenna consists of a square radiating patch and a ground plane with cross‐shaped slot and conductor‐backed plane, which provides a wide usable fractional bandwidth of more than 130% (3.06–12.87 GHz). By cutting a modified cross‐shaped slot with variable dimensions on the ground plane and also by inserting cross‐shaped conductor‐backed plane, additional resonances are excited and hence much wider impedance bandwidth can be produced, especially at the higher band. The designed antenna has a small size of 12 × 18 mm2. Simulated and experimental results obtained for this antenna show that it exhibits good radiation behavior within the UWB frequency range. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2656–2659, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27138

New monopole Antennafor Ultra Wideband Applications

There has been a flourishing prospect of UWB technology in recent years in both communication and other purposes like microwave imaging and radar applications. Recent studies of UWB antenna structures are specially concentrated on microstrip [1], slot and planar monopole antennas [2]. In this work, a small monopole antenna with diamond shape of the patch (30 x 26 mm2) printed microstrip fed monopole antenna has been designed, some parameters like return loss (S11), Voltage Standing Wave Ratio (VSWR), radiation pattern has been performed to test the validity of simulation and verify eligibility of the antenna for the wireless communications purpose. The proposed antenna is simulated in CST Microwave Studio and has surpassed the bandwidth of UWB requirement, which is from 3.1 to 10.6 GHz, and exhibits good UWB characteristics. The -10 dB return loss bandwidth of this antenna element is from 3.34 GHz to more than 19.5 GHz. General Terms Return-loss, Voltage Standing Wave Ratio (VSWR), 2D/3D Radiation Pattern, Gain.