Passive electromagnetic decoupling in an active metasurface of dipoles

Mollaei, Masoud Sharifian Mazraeh; Hurshkainen, Anna; Kurdjumov, S.; Glybovski, Stanislav; Simovski, Constantin

doi:10.1016/j.photonics.2018.10.001

Cited by 11 publications

(40 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Consider an array formed by three active dipoles and two passive SLRs located as shown in figure 1(a). Let us follow to the logics of our work [11] where the general condition of the decoupling was obtained in terms of the selfand mutual impedances and the geometry of the decoupling scatterers was not specified. For an array of three active dipoles and two passive scatterers we have (see also in figure 1(a)):…”

Section: Analytical Modelmentioning

confidence: 99%

“…Considering equations (2) and (3), any type of scatterers which satisfies these equations results in the decoupling between all three array elements. In [11], these decoupling conditions were satisfied by two passive dipoles identical to the active dipoles but shortcut at the center. It is possible to prove that replacing these passive dipoles by passive SLRs allows to satisfy these equations as well [12].…”

Section: Analytical Modelmentioning

confidence: 99%

“…In our previous works, first we introduced a method of passive decoupling between two and three closely resonant dipoles (d = λ/33 = 30 mm) by adding one and two the same but passive dipoles between them, respectively [11]. Using this approach, transmittance coefficient between active dipoles has been decreased from -2dB (for the reference case -without passive dipoles) to -13 dB while the relative bandwidth was 0.5% at the level of -8 dB.…”

Section: Introductionmentioning

confidence: 99%

“…Using this approach, transmittance coefficient between active dipoles has been decreased from -2dB (for the reference case -without passive dipoles) to -13 dB while the relative bandwidth was 0.5% at the level of -8 dB. Then in work [12], we have enhanced decoupling bandwidth between two active dipoles through replacing the passive dipole of [11] with a split-loop resonator (SLR). However, no one has used two and more SLRs to decouple dense arrays of dipole antennas.…”

Section: Introductionmentioning

confidence: 99%

“…In this paper, we aim to enhance operation band of dense dipole array through replacing two passive dipoles in [11] with the two passive SLRs. The possibility of decoupling in the dense array is discussed analytically, numerically and experimentally in next sections.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Double-resonant decoupling method in very dense dipole arrays

Mollaei

Hurshkainen

Kurdjumov

et al. 2020

Photonics and Nanostructures - Fundamentals and Applications

Self Cite

View full text Add to dashboard Cite

In this paper an approach for broadening of operational band in a dense array of dipole antennas by implementing passive split-loop resonators (SLRs) as decouplers is presented. Compared to the previous method, where three closely located active dipoles were decoupled by two passive dipole, the operational band is significantly improved from 0.5% to 1.6% at the same level of decoupling -8dB for the cross-talk and inter-channel transmittance. To delineate, the presence of two SLRs results in birefringence of the resonant interaction of SLRs which creates two different eigenmodes for decoupling. As a result, a dual-resonant decoupled band is obtained. Alongside with analytical investigation, numerical and experimental investigations verify the veracity of our approach. Moreover, the possibility of decoupling by SLRs for arrays with more active dipoles is investigated numerically.

show abstract

Section: Analytical Modelmentioning

confidence: 99%

Section: Analytical Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Double-resonant decoupling method in very dense dipole arrays

Mollaei

Hurshkainen

Kurdjumov

et al. 2020

Photonics and Nanostructures - Fundamentals and Applications

Self Cite

View full text Add to dashboard Cite

show abstract

Unshielded bent folded‐end dipole 9.4 T human head transceiver array decoupled using modified passive dipoles

Avdievich

Solomakha

Ruhm

et al. 2021

Magnetic Resonance in Med

View full text Add to dashboard Cite

show abstract

Folded‐end dipole transceiver array for human whole‐brain imaging at 7 T

et al. 2021

View full text Add to dashboard Cite

The advancement of clinical applications of ultrahigh field (UHF) MRI depends heavily on advances in technology, including the development of new radiofrequency (RF) coil designs. Currently, the number of commercially available 7 T head RF coils is rather limited, implying a need to develop novel RF head coil designs that offer superior transmit and receive performance. RF coils to be used for clinical applications must be robust and reliable. In particular, for transmit arrays, if a transmit channel fails the local specific absorption rate may increase, significantly increasing local tissue heating. Recently, dipole antennas have been proposed and used to design UHF head transmit and receive arrays. The dipole provides a unique simplicity while offering comparable transmit efficiency and signal-to-noise ratio with the conventional loop design. Recently, we developed a novel array design in our laboratory using a folded-end dipole antenna. In this work, we developed, constructed and evaluated an eight-element transceiver bent folded-end dipole array for human head imaging at 7 T. Driven in the quadrature circularly polarized mode, the array demonstrated more than 20% higher transmit efficiency and significantly better whole-brain coverage than that provided by a widely used commercial array. In addition, we evaluated passive dipole antennas for decoupling the proposed array. We demonstrated that in contrast to the common unfolded dipole array, the passive dipoles moved away from the sample not only minimize coupling between the adjacent folded-end active dipoles but also produce practically no destructive interference with the quadrature mode of the array.

show abstract

Passive electromagnetic decoupling in an active metasurface of dipoles

Cited by 11 publications

References 9 publications

Double-resonant decoupling method in very dense dipole arrays

Double-resonant decoupling method in very dense dipole arrays

Unshielded bent folded‐end dipole 9.4 T human head transceiver array decoupled using modified passive dipoles

Folded‐end dipole transceiver array for human whole‐brain imaging at 7 T

Contact Info

Product

Resources

About