Cross-Polarization Control in FSSs by Means of an Equivalent Circuit Approach

Molero, Carlos; Alex‐Amor, Antonio; Mesa, Francisco; Palomares‐Caballero, Ángel; Padilla, Pablo

doi:10.1109/access.2021.3096715

Cited by 19 publications

(10 citation statements)

References 53 publications

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“…As discussed in the Introduction, the study of timevarying diffraction gratings is a complex task. On the other hand, the analysis of their one-dimensional (1D) [46,47,51] and 2D [52][53][54][55] time-invariant (static) counterparts is a well-established topic in microwave and photonics communities. From a circuit standpoint, a static grating may be modeled as an equivalent admittance or impedance (see Appendix B for details) placed in between two transmission lines.…”

Section: A Equivalence Between Moving Media and The Space-time Modula...mentioning

confidence: 99%

Analysis of Metallic Space-Time Gratings Using Lorentz Transformations

Alex‐Amor¹,

Molero²,

Silveirinha³

2023

Phys. Rev. Applied

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This paper presents an analytical framework for the study of scattering and diffraction phenomena in space-time-modulated metallic gratings. Using a Lorentz transformation, it is shown that a particular class of space-time-modulated gratings behave effectively as moving media. We take advantage of this property to derive a closed analytical solution for the wave scattering problem. In particular, using our formalism it is possible to avoid space-time Floquet-Bloch expansions, as the solution of the problem in the original laboratory frame (grating parameters are periodic in space and time) is directly linked to a comoving frame where the metallic grating is time invariant (grating parameters are periodic only in space). In this way, we identify a fundamental connection between moving metallic gratings and space-time-modulated metamaterials, and exploit this link to study the nonreciprocal response of the structure. Some limitations and difficulties of the alternative nonrelativistic Galilean approach are discussed and the benefits of the Lorentz approach are highlighted. Finally, some analytical results are presented in order to validate the formalism. The results include scenarios involving TM (p) and TE (s) normal and oblique incidence, even beyond the onset of the diffraction regime. Furthermore, we show how the synthetic Fresnel drag can tailor the Goos-Hänchen effect and create a specular point shifted towards the direction of the synthetic motion, independent of the sign of the incidence angle.

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Section: A Equivalence Between Moving Media and The Space-time Modula...mentioning

confidence: 99%

Analysis of Metallic Space-Time Gratings Using Lorentz Transformations

Alex‐Amor¹,

Molero²,

Silveirinha³

2023

Phys. Rev. Applied

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“…Recent advances in circuit modeling have considered stacks of periodic 2-D arrays [78,86] and the potentials of these methods are somehow broader than expected [87]. Nonetheless, stacks of 2-D arrays do not really exploit the design the degrees of freedom associated with the longitudinal (propagating) direction.…”

Section: Circuit Modelsmentioning

confidence: 99%

3-D Metamaterials: Trends on Applied Designs, Computational Methods and Fabrication Techniques

2022

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Metamaterials are artificially engineered devices that go beyond the properties of conventional materials in nature. Metamaterials allow for the creation of negative refractive indexes; light trapping with epsilon-near-zero compounds; bandgap selection; superconductivity phenomena; non-Hermitian responses; and more generally, manipulation of the propagation of electromagnetic and acoustic waves. In the past, low computational resources and the lack of proper manufacturing techniques have limited attention towards 1-D and 2-D metamaterials. However, the true potential of metamaterials is ultimately reached in 3-D configurations, when the degrees of freedom associated with the propagating direction are fully exploited in design. This is expected to lead to a new era in the field of metamaterials, from which future high-speed and low-latency communication networks can benefit. Here, a comprehensive overview of the past, present, and future trends related to 3-D metamaterial devices is presented, focusing on efficient computational methods, innovative designs, and functional manufacturing techniques.

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“…Losses in dielectrics can be accounted in a straightforward manner. Simply replace the real-valued dielectric constant ε (i) r by the complex term [45] where tan δ (i) is the loss tangent term. A similar rationale can be applied for magnetic losses, where the relative permeability would also be defined by a complex-valued expression.…”

Section: G Dielectric and Magnetic Lossesmentioning

confidence: 99%

Time-varying Metallic Interfaces

Alex‐Amor¹,

Molero²

2022

Preprint

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This paper presents an analytical framework for the analysis of time-varying metallic metamaterials. Concretely, we particularize the study to time-modulated metallic interfaces embedded between two different semi-infinite media that are illuminated by monochromatic plane waves of frequency ω0. The formulation is based on a Floquet-Bloch modal expansion, which takes into account the time periodicity of the structure (Ts = 2π/ωs), and integral-equation techniques. It allows to extract the reflection/transmission coefficients as well as to derive nontrivial features about the dynamic response and dispersion curves of time-modulated screens. In addition, the proposed formulation has an associated equivalent circuit that gives physical insight to the diffraction phenomenon. Finally, some analytical results are presented to validate the present framework. A good agreement is observed with numerical computations provided by a self-implemented finite-difference time-domain (FDTD) method. Interestingly, the present results suggest that timemodulated metallic screens can be used either as pulsed sources (when ωs ω0) or as beamformers (when ωs ∼ ω0) to redirect energy in specific regions of space.

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Cross-Polarization Control in FSSs by Means of an Equivalent Circuit Approach

Cited by 19 publications

References 53 publications

Analysis of Metallic Space-Time Gratings Using Lorentz Transformations

Analysis of Metallic Space-Time Gratings Using Lorentz Transformations

3-D Metamaterials: Trends on Applied Designs, Computational Methods and Fabrication Techniques

Time-varying Metallic Interfaces

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