Investigation of polarization-independent wide-angle metamaterial inspired ISM-band absorber

In this paper, the polarization independent wide angle ISM-band metamaterial absorber structure has been investigated for various geometrical parameters along with the practical demonstration. The presented structure has been numerically simulated using full wave electromagnetic simulator exhibiting absorption peak of 99.42% at 2.48 GHz. The effects of variations in geometrical parameters have been manifested by designing and experimentally verifying two absorber structures with modified parameters, yielding near unity single absorption of 99.89% at 2.4 GHz while dual absorption of 97.2% and 98.1% at 1.76 GHz and 2.48 GHz, respectively. The unit cell of proposed absorber structure comprises of a closed ring resonators engraves on a grounded FR4 dielectric substrate. The simplicity of design imparts effortless fabrication and design symmetry provides polarization insensitivity. Additionally, it has been observed that the proposed structure could achieve high absorption of 90% up to 45° of incident transverse electric wave and up to 60° of transverse magnetic wave attains high absorption of 99%. The optimized absorber structures have been practically demonstrated using waveguide measurement technique and the outcomes are in good agreement with the numerically simulated results

Dual-band perfect meta material absorber with polarization independence and wide incidence angle

42-48A dual-band perfect meta-material absorber based on closed ring resonator structures (CRRs) with polarization independence and wide incidence angle stability is designed, simulated and measured. The absorber unit cell is composed of FR4 dielectric substrate sandwiched between the CRR and ground metal plane. The optimized design is numerically simulated to obtain two absorption peaks of around 99.66% at 1.98 GHz and 99.05% at 2.59 GHz. The proposed absorber structure exhibits absorption of above 99% for all polarization angle variations. The effect of variations in oblique angle under TE and TM mode configuration and loss tangent on absorption efficiency is presented to support the efficacy of the design. The numerical computation of design with a different dielectric material is performed to provide comparative result. The absorber structure is tested using waveguide measurement method which could be utilized for the absorption of the ambient UMTS band frequencies. The experimental results show fair agreement with the numerically simulated results

Compact Wideband Four Element Optically Transparent MIMO Antenna for mm-Wave 5G Applications

A four-element compact wide-band optically transparent MIMO antenna with a full ground plane is proposed. The four elements transparent MIMO system has a compact size of 24x20 mm(2) with the undivided ground plane as most of the real-time systems demand a common reference. The complete antenna system achieves around 85% transparency due to a combination of AgHT-8 and Plexiglas which forms the transparent conductive patch/ground and substrate, respectively. The antenna geometry leads dual-band operation ranging from 24.10 - 27.18 GHz (Impedance bandwidth D 12%) and 33 - 44.13 GHz (Impedance bandwidth D 28.86%) targeting the mm-wave 5G applications. The 4-element antenna system achieves isolation between inter-elements > 16 dB and maximum gain value of greater than 3 dBi with more than 75% efficiency. The proposed transparent MIMO antenna is evaluated in terms of diversity gain (DG), envelope correlation coefficient (ECC), total active reflection coefficient (TARC), and mean effective gain (MEG) where decent MIMO performance with isolation more than >16 dB between the adjacent and other elements is achieved. Transparent MIMO antenna achieves directional patterns for the operating band with the value of DG > 9, ECC < 0.1, TARC value less than and the ratio of MEG within the agreed limit of +/- 3 dB conforming acceptable MIMO/diversity performance

Aperture-Fed Quad-Port Dual-Band Dielectric Resonator-MIMO Antenna for Sub-6 GHz 5G and WLAN Application

A four-port dielectric resonator-based connected ground multiple-input multiple-output (MIMO) antenna is designed. The presented antenna was excited through the aperture feeding technique. The dual bands are achieved by optimally feeding the rectangular dielectric resonator through engineered triangular slots. The antenna has operating modes of TE111X and TE111Y at 4.5 GHz and 5 GHz, respectively. It presents a 2 : 1 VSWR bandwidth of 2.64% (4.48 GHz-4.60 GHz) and 1.2% (4.96 GHz-5.04 GHz) in the lower and upper bands, respectively. The edge-to-edge distance between array elements is around 7.5 mm. The single antenna dimension is 30 mm x 30 mm, whereas the four-port antenna dimension is 60 mm x 60 mm. The optimum isolation was achieved by carefully placing the antenna elements on the substrate through multiple iterations. The antenna provides port isolation better than 20 dB at both resonances with full ground profile. The advantage of the antenna is that it provides fair antenna and MIMO parameters without additional isolation techniques. The antenna has efficiency in order of 88.02% and 86.31%. The peak gain is 7.67 dBi and 8.32 dBi at 4.5 GHz and 5 GHz, respectively. The optimum envelope correlation coefficient (ECC) is 0.037, channel capacity coss (CCL) is 0.2 bits/sec/Hz, diversity gain (DG) is 9.99 dB, and total active reflection coefficient (TARC) is -18.87. The antenna elements are orthogonally placed with adequate separation to achieve polarization diversity and spatial diversity. The antenna provides the utilization in Sub-6 GHz 5G and WLAN communication applications

Four-Port Dual-Band Multiple-Input Multiple-Output Dielectric Resonator Antenna for Sub-6 GHz 5G Communication Applications

A four-port dielectric resonator (DR)-based multiple-input multiple-output (MIMO) antenna is presented for sub-6 GHz MIMO communication. The dielectric resonator was fed through aperture feeding to achieve dual-band resonance. The DRA has the operating modes of TE01δ and TE10δ at 3.3 GHz and 3.9 GHz, respectively. The engineered antenna has port isolation of higher than 20 dB at the target frequencies without the employment of an extra isolation mechanism. Full-wave high-frequency simulation software was employed for the simulation computation. The antenna has a peak gain of 5.8 dBi and 6.2 dBi, and an efficiency of 88.6% and 90.2% at 3.3 GHz and 3.9 GHz, respectively. The proposed resonator has good MIMO diversity parameters. The optimal envelope correlation coefficient (ECC) is 0.01, channel capacity loss (CCL) is 0.1 bits/sec/Hz, and the total active reflection coefficient (TARC) is −22.46. The DRA elements are aligned orthogonally with adequate displacement for achieving polarization diversity and spatial diversity. The antenna delivers its applications in Sub-6 GHz 5G and WiMAX communications

Investigation of polarization-independent wide-angle metamaterial inspired ISM-band absorber

63-73In this paper, the polarization independent wide angle ISM-band metamaterial absorber structure has been investigated for various geometrical parameters along with the practical demonstration. The presented structure has been numerically simulated using full wave electromagnetic simulator exhibiting absorption peak of 99.42% at 2.48 GHz. The effects of variations in geometrical parameters have been manifested by designing and experimentally verifying two absorber structures with modified parameters, yielding near unity single absorption of 99.89% at 2.4 GHz while dual absorption of 97.2% and 98.1% at 1.76 GHz and 2.48 GHz, respectively. The unit cell of proposed absorber structure comprises of a closed ring resonators engraves on a grounded FR4 dielectric substrate. The simplicity of design imparts effortless fabrication and design symmetry provides polarization insensitivity. Additionally, it has been observed that the proposed structure could achieve high absorption of 90% up to 45° of incident transverse electric wave and up to 60° of transverse magnetic wave attains high absorption of 99%. The optimized absorber structures have been practically demonstrated using waveguide measurement technique and the outcomes are in good agreement with the numerically simulated results

Meandered low profile multiband antenna for wireless communication applications

The compact slotted antenna having offset feed radiating in the multi-frequency bands is proposed. The antenna geometry comprises of a vertical and horizontally coupled slotted structure at the top with a complete ground plane at the bottom to achieve the proposed application bands. The patch is patterned on the FR4 substrate having a dielectric constant of 4.4 and loss tangent of 0.008. The antenna has an overall dimension of 0.18λ × 0.15λ mm2 (f = 1.52 GHz) with offset fed which is optimized to achieve 50 Ω impedance matching. The proposed compact antenna resonates in pentaband frequency bands which includes 1.52–1.60 GHz for GPS (ISM band in India), 2.97–3.02 GHz for Radio frequency identification and detection, mobile communication, logistics, manufacturing, transportation and healthcare, 3.73–3.84 GHz for Amateur Fixed Mobile except aeronautical mobile (R), 4.42–4.52 GHz for radio communications, TransferJet USB Adapter (Toshiba Corporation), and 4.83–4.96 GHz for Aviation Private Land Mobile applications. The proposed antenna has demonstrated a decent gain ranging from 1.07 to 3.92 dBi having omnidirectional and bidirectional radiation patterns, hence, making it suitable for various wireless applications

Quad-port MIMO antenna with high isolation characteristics for sub 6-GHz 5G NR communication

Abstract A four-port MIMO antenna with high isolation is presented. The antenna is primarily envisioned to cover the n48 band of Frequency Range-1 (FR-1) with TDD duplex mode. The engineered antenna has electrical dimensions of 90 × 90 × 1.57 mm3. The size miniaturization of a single antenna unit is achieved through an optimized placement of slots and extended arms. The quad-antennas are then placed orthogonally to achieve antenna diversity. The antenna resonates at 3.56 GHz and 5.28 GHz having 2:1 VSWR fractional bandwidth of 1.82% and 2.12%. The proposed resonator provides 88.34% and 79.28% efficiency at lower and upper bands, respectively. The antenna is an exceptional radiator regarding MIMO diversity performance owing to high inter-element isolation. The values of envelope correlation coefficient < 0.05, channel capacity loss is nearly 0.1 bits/sec/Hz, and total active reflection coefficient is − 24.26. The full ground plane profile aids in high directivity and cross-pol isolation. The antenna exhibits a gain of 4.2 dBi and 2.8 dBi, respectively, justifying intended application requirements. There is a good coherence between simulation and experimental results. The self-decoupled antenna poses its application in 5G and WLAN Communication Applications