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Journal ArticleDOI

Compact wideband hybrid fractal antenna loaded on AMC reflector with enhanced gain for hybrid wireless cellular networks

TL;DR: In this article, a wideband hybrid fractal monopole antenna loaded with artifical magnetic conductor (AMC) is proposed, which achieves self-similarity compactness, reduced size and good wideband performances.
Abstract: A wideband hybrid fractal monopole antenna loaded with artifical magnetic conductor (AMC) is proposed. Using a hybrid fractal generator, the monopole antenna achieves self-similarity compactness, reduced size and good wideband performances. The ground is semi-elliptic and has defected steps aiming to improve impedance matching and X-pol. reduction. The AMC reflector has 3 × 3 array of cesaro shaped unit cells looped in a square metallic conductor. The AMC enhances radiation gain with back-lobe reduction. The AMC unit cell produce a 0 0 phase reflection at f AMC = 4.5 GHz and then loaded to optimize antenna performance. To validate the design, a prototype antenna is fabricated and measured. The antenna operates from (3.7–7.0) GHz with 61.68% impedance bandwidth, realized gain of (8.7–13.8) dBi, and radiation efficiency > 82.5%. The proposed antenna leverages on compactness, low-profile AMC height and good boresight radiation gain, which shows its potential for hybrid wireless cellular networks.
Citations
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Journal ArticleDOI
TL;DR: In this article, a high gain and wideband multiple-input multiple-output (MIMO) for 5G new radio (NR) networks is introduced, where an artificial magnetic conductor (AMC) is located underneath the MIMO antenna to improve the gain by about 55% over the entire achieved frequency band (26-31.5 GHz).
Abstract: A high gain and wideband multiple-input multiple-output (MIMO) for 5G new radio (NR) networks is introduced in this paper. The single unit is a monopole antenna with partial ground plane and two small triangles are cut out from the patch to produce the proposed frequency band. The two elements are located orthogonal to each other in order to reduce the mutual coupling without using isolation structure at the desired frequency 28 GHz. An artificial magnetic conductor (AMC) is located underneath the MIMO antenna to improve the gain by about 55% over the entire achieved frequency band (26-31.5 GHz). The Suggested antenna model with the AMC structure is fabricated to verify the simulation results in terms of S-parameters, radiation patterns, gain, and diversity parameters. It is worth noting that the experimental results have the same trend of the simulation ones which makes the suggested AMC-based MIMO antenna applicable for 5G NR networks.

23 citations

Journal ArticleDOI
TL;DR: In this paper , a planar super wideband (SWB) antenna with the dimension of 35 × 30 × 0.8 mm3 operating over 2.8-40 GHz (14.28:1) spectrum is proposed.
Abstract: A small bulb shaped planar super wideband (SWB) antenna with the dimension of 35 × 30 × 0.8 mm3 operating over 2.8–40 GHz (14.28:1) spectrum is proposed. The antenna offers a fractional bandwidth of 173.8%, bandwidth dimension ratio (BDR) of 1904, measured peak gain of 5.5 dBi and radiation efficiency of 80%. The proposed antenna is unified to an unique SWB frequency selective surface (FSS), having unit cell size equal to 0.114λL × 0.114λL × 0.008λL (λL is the wavelength at 3.1 GHz). The FSS operates in 3.05 to 35.92 GHz spectrum (168.7%) with transmission level S21 ≤ -10 dB and reflection S11 near 0 dB for TE and TM modes of polarization with adequate angular stability. The linearly decreasing S11 phase of FSS makes it appropriate for radiation improvement of the bulb shaped antenna in the broadside direction by placing the antenna at the top of FSS with an optimal air gap of 19 mm. The SWB ‘antenna-FSS’ exhibits wideband response over 3–36.2 GHz (169.4%) spectrum, including commercial ultra-wideband (3.1–10.6 GHz), ISM bands (5.725–5.875 GHz & 24–24.25 GHz), WiMAX (3.3–3.7 GHz), IEEE 802.11 WLAN bands, S-C-X-Ku-Ka bands, and 5G NR (n77, n78, n79, n257, n258, n261) bandwidth with stable and adequate gain of 5.2–7.16 dBi and an acceptable radiation efficiency.

19 citations

Journal ArticleDOI
01 Aug 2022
TL;DR: In this article , a single-layered metasurface-loaded high-gain and broadband polarization reconfigurable λ o /4 printed monopole antenna is investigated, where the proposed antenna configuration comprises of Y-shaped radiating monopole over partial ground plane with the extended twin parasitic conducting strips (PCS), is loaded with a single layer reflector.
Abstract: • Broadband circularly polarized antennas with enhanced CP gain & improved radiation are important from application perspectives. • Proposed antenna exhibits effective attributes & integration with active elements leads to polarization reconfigurability. • Concurrent analysis about CP relates understanding with the classical electromagnetics. • The proposed implicit technique in form of a single-layered metasurface is capable of improving performance trade-offs. • Elaboration of physical insights & theoretical intuition provide support to the generic solution. A single-layered metasurface-loaded high-gain & broadband polarization reconfigurable λ o /4 printed monopole antenna is investigated in this article. The proposed antenna configuration comprises of Y-shaped radiating monopole over partial ground plane with the extended twin parasitic conducting strips (PCS), is loaded with a single-layered metasurface (MS) reflector. To attain circular polarization (CP) characteristics, a BAR 50-02 V PIN Diode from Infineon is used to short the partial ground plane and one of the twin parasitic conducting strips (PCS-L). By utilizing the grid-slotted sub patches on the rectangular reflecting surfaces of MS layer with a volumetric dimension of 2λ o × 1.65λ o × 0.02λ o , is placed just below Y-shaped monopole radiator (PYMA) at a height of 0.33λ o , in which broadened impedance (IBW) and 3-dB axial ratio bandwidth (ARBW) with the enhanced CP antenna gain are achieved. Finally, proposed prototype of 1.33λ o × 0.9λ o × 0.02λ o , where λ o = 5 GHz is fabricated and measured. It offers an measured IBW of 48.45 % (3.57–5.85 GHz), ARBW of 25.96 % (4.19–5.44 GHz) and the CP antenna gain of >8.35 dBic with antenna efficiency of >75 % in the desired operating bands. From the above results, the performance of single-layered metasurface-inspired polarization reconfigurable antenna confirms its suitability for hybrid wireless applications and also, it can be extended towards the scope of designing efficient RF energy harvesting system.

13 citations

Journal ArticleDOI
TL;DR: In this article , a compact 8-port UWB MIMO antenna was proposed to operate from (2.5-24) GHz with 162.2% impedance bandwidth, and the isolation improvement mechanism was achieved by conjoining an annular reflector at top with the ground plane via metallic vias.
Abstract: In this article, a compact 8-port UWB MIMO antenna was proposed to operate from (2.5–24) GHz with 162.2% impedance bandwidth. To achieve space diversity, i.e., maximum antenna elements accomodated in a premium foot-print, each radiating pairs are designed with self-similar hybrid geometry and oriented in side-by-side orthogonal configuration. The substrate corners are cut-out for maximum free space radiation and volumetric reduction. The isolation improvement mechanism is achieved by conjoining an annular reflector at top with the ground plane via metallic vias. The metal vias magnetically couple reflector and the ground plane into a connected topology. The annular reflector has dual-purpose, firstly, the contra-cyclic surface current symmetry improves the lower mode impedance matching and secondly, port-isolation is achieved (>22 dB) by electrically self-neutralize near-field radiated currents due to contra-rotational E-field NULL distributions. The antenna MIMO diversity performances show good attributes for indoor and outdoor wireless environments. To validate, a prototype antenna of size 48 mm × 48 mm (0.4λ×0.4λ,λ = operating wavelength at 2.5 GHz) was fabricated and measured. The simulated and measured results has good agreements to be explored in UWB MIMO systems, microwave telemetry, tracking and RF doppler sensor applications.

4 citations

References
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Journal ArticleDOI
TL;DR: In this paper, a new type of metallic structure has been developed that is characterized by having high surface impedance, which is analogous to a corrugated metal surface in which the corrugations have been folded up into lumped-circuit elements and distributed in a two-dimensional lattice.
Abstract: A new type of metallic electromagnetic structure has been developed that is characterized by having high surface impedance. Although it is made of continuous metal, and conducts dc currents, it does not conduct ac currents within a forbidden frequency band. Unlike normal conductors, this new surface does not support propagating surface waves, and its image currents are not phase reversed. The geometry is analogous to a corrugated metal surface in which the corrugations have been folded up into lumped-circuit elements, and distributed in a two-dimensional lattice. The surface can be described using solid-state band theory concepts, even though the periodicity is much less than the free-space wavelength. This unique material is applicable to a variety of electromagnetic problems, including new kinds of low-profile antennas.

4,264 citations

Journal ArticleDOI
TL;DR: In this article, the authors introduce several different design methodologies for multiband artificial magnetic conducting (AMC) surfaces, based on the introduction of FSS screens that have fractal or nearly fractal unit cell geometries.
Abstract: This paper introduces several different design methodologies for multiband artificial magnetic conducting (AMC) surfaces. The paper begins by investigating the multiband properties exhibited by a conventional electromagnetic bandgap (EBG) AMC that consists of a frequency selective surface (FSS) on top of a thin dielectric substrate with a PEC back plane. The higher-order resonances associated with these surfaces have not been discussed in detail to date, as previous research has been concerned only with exploiting the primary resonant frequency. However, it will be shown that by understanding and making appropriate use of these higher order resonances, it is possible to design multiband AMC surfaces that work for nearly any desired combination of operating frequencies. The first multiband AMC design approach that will be considered is based on the introduction of FSS screens that have fractal or nearly fractal unit cell geometries. This is followed by a more general and robust genetic algorithm (GA) technique for the synthesis of optimal multiband AMC surfaces. In this case, a GA is used to evolve multiband AMC surface designs by simultaneously optimizing the geometry and size of the FSS unit cell as well as the thickness and dielectric constant of the substrate material. Finally, several examples of multiband AMC surfaces are presented, including some practical dual-band and tri-band designs genetically evolved for operation at GPS and cellular frequencies, as well as an example illustrating the success in creating a multiband AMC surface with angular stability.

384 citations

Patent
15 Apr 2010
TL;DR: In this paper, a new class of Ultra-Wide Band (UWB) AMC with very large fractional bandwidth (>100%) even at lower frequencies (<1 GHz was demonstrated.
Abstract: This disclosure demonstrates a new class of Ultra-Wide Band (UWB) AMC with very large fractional bandwidth (>100%) even at lower frequencies (<1 GHz). This new UWB AMC is enabled by recognizing that any AMC must be an antenna in order to accept the incident radiation into the circuit. Therefore, by using UWB antenna design features, one can make wide band AMCs. Additionally, by manipulation of the UWB AMC element design, a 1/frequency dependence can be obtained for instantiating the benefits of a quarter wave reflection over a large UWB bandwidth with a single physical thickness.

209 citations

Journal ArticleDOI
TL;DR: In this article, a theoretical study on frequency selective surfaces (FSS) with application to artificial magnetic conductors or high-impedance surfaces (HIS) is presented, where a stable resonance was found for the case of series-resonance grids without vias in the slab.
Abstract: The work presented in this paper concerns a theoretical study on frequency selective surfaces (FSS) with application to artificial magnetic conductors or high-impedance surfaces (HIS). Current realizations of HIS are based on a planar FSS at the interface of a metal-backed dielectric slab either including vertical vias or not. A stable resonance was found for the case of series-resonance grids without vias in the slab. The resonance turns out to be unique in theory for all angles of incidence and both polarizations of plane waves illuminating the HIS. It was shown that vias destroy the stabilization effect and introduce a frequency shift. The analytical model was validated by HFSS simulations.

189 citations

Journal ArticleDOI
Min Li1, Qinlong Li1, Bo Wang1, Changfei Zhou1, Sing Wai Cheung1 
TL;DR: In this article, a low profile dual-polarized dipole antenna using wideband artificial magnetic conductor (AMC) reflector with stable radiation pattern for use in 2G/3G/4G base stations operating from 1.7 to 2.7 GHz is presented.
Abstract: A low-profile dual-polarized dipole antenna using wideband artificial magnetic conductor (AMC) reflector with stable radiation pattern for use in 2G/3G/4G base stations operating from 1.7 to 2.7 GHz is presented. The antenna consists of a pair of crossed-dipoles and a wideband AMC reflector which consists of an AMC surface, a metallic ground plane, and the air substrate between them. The AMC is designed to operate with 90° reflection-phase bandwidth of 1.64–2.88 GHz (54.8%). Compared with using perfect electric conductor reflector, the profile height of the dual-polarized dipole antenna using AMC reflector is reduced by half from 36 to 18 mm, resulting in the lowest-profile 2G/3G/4G base station antenna. Six metallic ground walls are used to stabilize the radiation pattern, and the resulted half-power beamwidths are around 68±3° and 81±3° in the H- and V-planes, respectively, across the operating band. More measured results show that wide impedance bandwidths of 1.67–2.98 and 1.64–3.05 GHz for the two input ports, isolation of more than 25 dB, and cross-polarization of less than −20 dB are achieved.

128 citations