Magnetism from conductors and enhanced nonlinear phenomena
01 Nov 1999-IEEE Transactions on Microwave Theory and Techniques (IEEE)-Vol. 47, Iss: 11, pp 2075-2084
TL;DR: In this paper, it was shown that microstructures built from nonmagnetic conducting sheets exhibit an effective magnetic permeability /spl mu/sub eff/, which can be tuned to values not accessible in naturally occurring materials.
Abstract: We show that microstructures built from nonmagnetic conducting sheets exhibit an effective magnetic permeability /spl mu//sub eff/, which can be tuned to values not accessible in naturally occurring materials, including large imaginary components of /spl mu//sub eff/. The microstructure is on a scale much less than the wavelength of radiation, is not resolved by incident microwaves, and uses a very low density of metal so that structures can be extremely lightweight. Most of the structures are resonant due to internal capacitance and inductance, and resonant enhancement combined with compression of electrical energy into a very small volume greatly enhances the energy density at critical locations in the structure, easily by factors of a million and possibly by much more. Weakly nonlinear materials placed at these critical locations will show greatly enhanced effects raising the possibility of manufacturing active structures whose properties can be switched at will between many states.
Citations
More filters
TL;DR: One of the most important processes in the fight against current and future pandemics is the rapid diagnosis and initiation of treatment of viruses in humans as mentioned in this paper . But this process is difficult and time-consuming.
Abstract: One of the most important processes in the fight against current and future pandemics is the rapid diagnosis and initiation of treatment of viruses in humans. In these times, the...
17 Aug 2022
TL;DR: In this article , the design of complementary split ring resonator and its equivalent circuit is discussed, which provides both isolation enhancement and miniaturization for MIMO antenna for wireless networks.
Abstract: Metamaterials (MTMs) are artificially built materials intended to give its properties from the internal structure, rather than the chemical composition found in natural materials. Electric permittivity (ε) and magnetic permeability (μ) are the two basic parameters which describe the electromagnetic property of a material or medium. Permittivity describes how a material is affected when it is placed in electric field. And permeability describes how a material is affected in presence of magnetic field. Metamaterials may have either negative permittivity or permeability or both may be negative simultaneously. The concept of metamaterials has additionally been utilized to design different kinds of patches with upgraded performance, such as improved gain and enhanced efficiency. Also, it has been utilized for the scaling down of patches. Two parameters are utilized in the collected works for antennas using metamaterials. We can adjust the refractive index of the metamaterial to positive, near-zero or negative values. Utilization of epsilon negative, MNG (μ - Mu negative) or DNG (double negative) are called metamaterial- based antennas and the use of metamaterial unit cell for example complementary split ring resonator, split ring resonator and so on are alluded as metamaterial inspired antennas. The design of complementary split ring resonator and its equivalent circuit will be discussed in this work. CSRR (complementary split ring resonator) provides both isolation enhancement and miniaturization for MIMO antenna.
TL;DR: In this article , the fundamental concept and salient details about passive resonators in chipless radio frequency identification (RFID) technology are presented in a review article and the analysis also intends to assist the advancement of chipless auto-identification technology by addressing constraints, such as price, physical footprint, and coding capacity.
Abstract: The fundamental concept and salient details about passive resonators in chipless radio frequency identification (RFID) technology are presented in this review article. The analysis also intends to assist the advancement of chipless autoidentification technology by addressing constraints, such as price, physical footprint, and coding capacity. The study makes it clear that resonators are the fundamental building blocks of modern chipless RFID industries. They are capable enough to enhance the detection performance, encoding ability, and information storage capacity that increase the usage of the transponder in a multitude of applications in various retailing and medical domains. Importance is given to smart materials and metamaterials that utilize resonators from an industrial standpoint. This article examines current developments in RFID resonators and the problems that they inevitably bring with them, such as sensitivity, selectivity, interference, collision, polarization, and read range.
18 Feb 2023
TL;DR: In this paper , a double-layer metasurface radome is proposed to achieve high transmission characteristics at large angular incidence in Ku-band, allowing the antenna to maintain its good performance.
Abstract: Ku-band antennas are playing an increasingly important role in satellite communication systems, and microwave radomes exhibiting bandpass behavior are highly desirable for antenna systems. In this paper, we propose a double-layer metasurface radome which can show high transmission characteristics at large angular incidence in Ku-band, allowing the antenna to maintain its good performance. The joint simulation results of this radome and antenna show that such metasurface exhibits insertion loss < 1dB within $\pm 50^{\circ}$ oblique angle incidence in the $16\sim 17$ GHz.
References
More filters
TL;DR: If a three-dimensionally periodic dielectric structure has an electromagnetic band gap which overlaps the electronic band edge, then spontaneous emission can be rigorously forbidden.
Abstract: It has been recognized for some time that the spontaneous emission by atoms is not necessarily a fixed and immutable property of the coupling between matter and space, but that it can be controlled by modification of the properties of the radiation field. This is equally true in the solid state, where spontaneous emission plays a fundamental role in limiting the performance of semiconductor lasers, heterojunction bipolar transistors, and solar cells. If a three-dimensionally periodic dielectric structure has an electromagnetic band gap which overlaps the electronic band edge, then spontaneous emission can be rigorously forbidden.
12,787 citations
"Magnetism from conductors and enhan..." refers background in this paper
...In fact, metallic structures in general represent a fresh approach to the photonic insulator concept introduced independently by Yablonovitch [8], [9] and John [10]....
[...]
TL;DR: A new mechanism for strong Anderson localization of photons in carefully prepared disordered dielectric superlattices with an everywhere real positive dielectrics constant is described.
Abstract: A new mechanism for strong Anderson localization of photons in carefully prepared disordered dielectric superlattices with an everywhere real positive dielectric constant is described. In three dimensions, two photon mobility edges separate high- and low-frequency extended states from an intermediate-frequency pseudogap of localized states arising from remnant geometric Bragg resonances. Experimentally observable consequences are discussed.
9,067 citations
TL;DR: A mechanism for depression of the plasma frequency into the far infrared or even GHz band is proposed: Periodic structures built of very thin wires dilute the average concentration of electrons and considerably enhance the effective electron mass through self-inductance.
Abstract: The plasmon is a well established collective excitation of metals in the visible and near UV, but at much lower frequencies dissipation destroys all trace of the plasmon and typical Drude behavior sets in. We propose a mechanism for depression of the plasma frequency into the far infrared or even GHz band: Periodic structures built of very thin wires dilute the average concentration of electrons and considerably enhance the effective electron mass through self-inductance. Computations replicate the key features and confirm our analytic theory. The new structure has novel properties not observed before in the GHz band, including some possible impact on superconducting properties.
3,954 citations
TL;DR: In this paper, the angle energy distribution of a fast electron losing energy to conduction electrons in a thick metallic foil has been derived assuming that the conduction electron constitute a Fermi-Dirac gas and that the fast electron undergoes only small fractional energy and momentum changes.
Abstract: The angle-energy distribution of a fast electron losing energy to the conduction electrons in a thick metallic foil has been derived assuming that the conduction electrons constitute a Fermi-Dirac gas and that the fast electron undergoes only small fractional energy and momentum changes. This distribution exhibits both collective interaction characteristics and individual interaction characteristics, and is more general than the result obtained by other workers. Describing the conduction electrons by the hydro-dynamical equations of Bloch, it has been shown that for very thin idealized foils energy loss may occur at a value which is less than the plasma energy, while as the foil thickness decreases below $\ensuremath{\sim}\frac{v}{{\ensuremath{\omega}}_{p}}$ the loss at the plasma energy becomes less than that predicted by more conventional theories. The net result is an increase in the energy loss per unit thickness as the foil thickness is decreased. It is suggested that the predicted loss at subplasma energies may correspond to some of the low-lying energy losses which have been observed by experimenters using thin foils.
2,623 citations
TL;DR: In this article, the behavior of the electrons in a dense electron gas is analyzed quantum-mechanically by a series of canonical transformations, and the results are related to the classical density fluctuation approach and Tomonaga's one-dimensional treatment of the degenerate Fermi gas.
Abstract: The behavior of the electrons in a dense electron gas is analyzed quantum-mechanically by a series of canonical transformations. The usual Hamiltonian corresponding to a system of individual electrons with Coulomb interactions is first re-expressed in such a way that the long-range part of the Coulomb interactions between the electrons is described in terms of collective fields, representing organized "plasma" oscillation of the system as a whole. The Hamiltonian then describes these collective fields plus a set of individual electrons which interact with the collective fields and with one another via short-range screened Coulomb interactions. There is, in addition, a set of subsidiary conditions on the system wave function which relate the field and particle variables. The field-particle interaction is eliminated to a high degree of approximation by a further canonical transformation to a new representation in which the Hamiltonian describes independent collective fields, with ${n}^{\ensuremath{'}}$ degrees of freedom, plus the system of electrons interacting via screened Coulomb forces with a range of the order of the inter electronic distance. The new subsidiary conditions act only on the electronic wave functions; they strongly inhibit long wavelength electronic density fluctuations and act to reduce the number of individual electronic degrees of freedom by ${n}^{\ensuremath{'}}$. The general properties of this system are discussed, and the methods and results obtained are related to the classical density fluctuation approach and Tomonaga's one-dimensional treatment of the degenerate Fermi gas.
1,407 citations
"Magnetism from conductors and enhan..." refers background in this paper
...of the plasma modes of a gas of free electrical charges [6], [7]....
[...]