Publications

Zinser, Brian; Langston, William L.; Kotulski, J.D.; Coats, Rebecca S.; Jorgenson, Roy E.; Blake, Samuel A.; Campione, Salvatore; Pung, Aaron J.; Zinser, Brian

Abstract not provided.

Progress In Electromagnetics Research C

Campione, Salvatore; Warne, Larry K.; Langston, William L.; Basilio, Lorena I.

In this paper, we report the formulation to account for dielectrics in a first principles multipole-based cable braid electromagnetic penetration model. To validate our first principles model, we consider a one-dimensional array of wires, which can be modeled analytically with a multipole-conformal mapping expansion for the wire charges; however, the first principles model can be readily applied to realistic cable geometries. We compare the elastance (i.e., the inverse of the capacitance) results from the first principles cable braid electromagnetic penetration model to those obtained using the analytical model. The results are found in good agreement up to a radius to half spacing ratio of 0.5–0.6, depending on the permittivity of the dielectric used, within the characteristics of many commercial cables. We observe that for typical relative permittivities encountered in braided cables, the transfer elastance values are essentially the same as those of free space; the self-elastance values are also approximated by the free space solution as long as the dielectric discontinuity is taken into account for the planar mode.

Proceedings of the 2017 19th International Conference on Electromagnetics in Advanced Applications, ICEAA 2017

Campione, Salvatore; Warne, Larry K.; Coats, Rebecca S.; Langston, William L.; Basilio, Lorena I.; Johnson, W.A.

We propose a cable braid electromagnetic penetration model that is based on first-principles and is derived strictly from the geometrical parameters of the cable in question. We apply this formulation to the case of a one-dimensional array of wires, which can also be modeled analytically via a multipole-conformal mapping expansion for the wire charges and is extended by means of Laplace solutions in bipolar coordinates. Both electric and magnetic penetrations are analyzed, and comparisons are performed between results from the first principles cable braid electromagnetic penetration model and those obtained using the multipole-conformal mapping expansion method. We find results in very good agreement when using up to the octopole moment (for the first principles model), covering a dynamic range of radius-to-half-spacing ratio up to 0.6. These results give us the confidence that our first principles model is applicable to the geometric characteristics of many commercial cables.

Basilio, Lorena I.; Campione, Salvatore; Warne, Larry K.; Langston, William L.

Abstract not provided.

Campione, Salvatore; Warne, Larry K.; Langston, William L.; Johnson, William A.; Coats, Rebecca S.; Basilio, Lorena I.

Abstract not provided.

Campione, Salvatore; Warne, Larry K.; Langston, William L.; Johnson, William A.; Coats, Rebecca S.; Basilio, Lorena I.

Abstract not provided.

IEEE Transactions on Electromagnetic Compatibility

Campione, Salvatore; Warne, Larry K.; Langston, William L.; Johnson, William A.; Coats, Rebecca S.; Basilio, Lorena I.

In this paper, we investigate the electric penetration case of the first principles multipole-based cable braid electromagnetic penetration model reported in the Progress in Electromagnetics Research B 66, 63–89 (2016). We first analyze the case of a 1-D array of wires: this is a problem which is interesting on its own, and we report its modeling based on a multipole-conformal mapping expansion and extension by means of Laplace solutions in bipolar coordinates. We then compare the elastance (inverse of capacitance) results from our first principles cable braid electromagnetic penetration model to that obtained using the multipole-conformal mapping bipolar solution. These results are found in a good agreement up to a radius to half spacing ratio of 0.6, demonstrating a robustness needed for many commercial cables. We then analyze realistic cable implementations without dielectrics and compare the results from our first principles braid electromagnetic penetration model to the semiempirical results reported by Kley in the IEEE Transactions on Electromagnetic Compatibility 35, 1–9 (1993). Finally, although we find results on the same order of magnitude of Kley's results, the full dependence on the actual cable geometry is accounted for only in our proposed multipole model which, in addition, enables us to treat perturbations from those commercial cables measured.

Campione, Salvatore; Warne, Larry K.; Langston, William L.; Johnson, William A.; Coats, Rebecca S.; Basilio, Lorena I.

Abstract not provided.

Basilio, Lorena I.; Campione, Salvatore; Warne, Larry K.; Langston, William L.

Abstract not provided.

Campione, Salvatore; Warne, Larry K.; Basilio, Lorena I.; Langston, William L.; Sinclair, Michael B.

Abstract not provided.

ACS Photonics

Campione, Salvatore; Liu, Sheng L.; Basilio, Lorena I.; Warne, Larry K.; Langston, William L.; Luk, Ting S.; Wendt, J.R.; Reno, J.L.; Keeler, Gordon A.; Brener, Igal; Sinclair, Michael B.

We present a new approach to dielectric metasurface design that relies on a single resonator per unit cell and produces robust, high quality factor Fano resonances. Our approach utilizes symmetry breaking of highly symmetric resonator geometries, such as cubes, to induce couplings between the otherwise orthogonal resonator modes. In particular, we design perturbations that couple "bright" dipole modes to "dark" dipole modes whose radiative decay is suppressed by local field effects in the array. Our approach is widely scalable from the near-infrared to radio frequencies. We first unravel the Fano resonance behavior through numerical simulations of a germanium resonator-based metasurface that achieves a quality factor of ∼1300 at ∼10.8 μm. Then, we present two experimental demonstrations operating in the near-infrared (∼1 μm): a silicon-based implementation that achieves a quality factor of ∼350; and a gallium arsenide-based structure that achieves a quality factor of ∼600, the highest near-infrared quality factor experimentally demonstrated to date with this kind of metasurface. Importantly, large electromagnetic field enhancements appear within the resonators at the Fano resonant frequencies. We envision that combining high quality factor, high field enhancement resonances with nonlinear and active/gain materials such as gallium arsenide will lead to new classes of active optical devices.

2016 URSI International Symposium on Electromagnetic Theory, EMTS 2016

Campione, Salvatore; Basilio, Lorena I.; Warne, Larry K.; Langston, William L.

Cable shielding to protect against coupling of electromagnetic radiation into a component or circuit, particularly over large frequency bands, is at times a challenging task. It is general understanding that increasing the number of shields of a cable will improve the shielding performance. However, there are situations in which a cable with multiple shields may perform similar to or in some cases worse than a cable with a single shield, and this analysis has seldom been discussed in the literature. We intend to shed more light onto this topic in this paper.

2016 URSI International Symposium on Electromagnetic Theory, EMTS 2016

Campione, Salvatore; Basilio, Lorena I.; Warne, Larry K.; Langston, William L.; Luk, Ting S.; Wendt, J.R.; Liu, Sheng L.; Brener, Igal B.; Sinclair, Michael B.

Metamaterial dielectric resonators represent a promising path toward low-loss metamaterials at optical frequencies. In this paper we utilize perturbations of high symmetry resonator geometries, such as cubes, either to overlap the electric and magnetic dipole resonances, thereby enabling directional scattering and Huygens' metasurfaces, or to induce couplings between the otherwise orthogonal resonator modes to achieve high-quality factor Fano resonances. Our results are fully scalable across any frequency bands where high-permittivity dielectric materials are available, including microwave, THz, and infrared frequencies.

Warne, Larry K.; Jorgenson, Roy E.; Williams, Jeffery T.; Basilio, Lorena I.; Coats, Rebecca S.; Campione, Salvatore; Chen, Kenneth C.; Langston, William L.

This report examines bounds on the penetrant power through ports of entry into a conductive cavity. We first replace the cavity by a load and consider the maximum power transfer properties of an antenna or an aperture. We consider how limitations on the load quality factor place limits on received power. For general frequency ranges we model the backing region by means of a uniformly distributed matched load along a slot aperture and adjust its value for maximum power transfer. This result is derived in closed form using a transmission line model for the aperture. This result illustrates the reduction in received power for low frequencies with finitely conducting wall materials. At high frequencies it approaches the receiving cross section of a linear array having the slot length dimension. Next we examine a slot aperture in a conducting rectangular enclosure and determine how the cavity wall losses and resulting quality factor limit the penetrant power. Detailed simulations and experimental measurements are compared with each other and with the bounding results to assess the accuracy of the bounds. These comparisons also indicate limitations on the accuracy of the models due to perturbing influences in construction, such as bolted joints.

Campione, Salvatore; Basilio, Lorena I.; Warne, Larry K.; Langston, William L.; Luk, Ting S.; Wendt, J.R.; Liu, Sheng L.; Brener, Igal B.; Sinclair, Michael B.

Abstract not provided.

Campione, Salvatore; Basilio, Lorena I.; Warne, Larry K.; Langston, William L.

Abstract not provided.

Progress In Electromagnetics Research C

Campione, Salvatore; Basilio, Lorena I.; Warne, Larry K.; Hudson, Howard G.; Langston, William L.

In this paper we report on a transmission-line model for calculating the shielding effectiveness of multiple-shield cables with arbitrary terminations. Since the shields are not perfect conductors and apertures in the shields permit external magnetic and electric fields to penetrate into the interior regions of the cable, we use this model to estimate the effects of the outer shield current and voltage (associated with the external excitation and boundary conditions associated with the external conductor) on the inner conductor current and voltage. It is commonly believed that increasing the number of shields of a cable will improve the shielding performance. However, this is not always the case, and a cable with multiple shields may perform similar to or in some cases worse than a cable with a single shield. We want to shed more light on these situations, which represent the main focus of this paper.

Progress In Electromagnetics Research B

Warne, Larry K.; Langston, William L.; Basilio, Lorena I.; Johnson, William A.

The model for penetration of a wire braid is rigorously formulated. Integral formulas are developed from energy principles for both self and transfer immittances in terms of potentials for the fields. The detailed boundary value problem for the wire braid is also set up in a very efficient manner; the braid wires act as sources for the potentials in the form of a sequence of line multipoles with unknown coefficients that are determined by means of conditions arising from the wire surface boundary conditions. Approximations are introduced to relate the local properties of the braid wires to a simplified infinite periodic planar geometry. This is used to treat nonuniform coaxial geometries including eccentric interior coaxial arrangements and an exterior ground plane.

Sinclair, Michael B.; Campione, Salvatore; Liu, Sheng L.; Warne, Larry K.; Basilio, Lorena I.; Luk, Ting S.; Wendt, J.R.; Langston, William L.

Abstract not provided.

Warne, Larry K.; Langston, William L.; Basilio, Lorena I.; Johnson, W.A.

The model for penetration of a wire braid is rigorously formulated. Integral formulas are developed from energy principles and reciprocity for both self and transfer immittances in terms of potentials for the fields. The detailed boundary value problem for the wire braid is also setup in a very efficient manner; the braid wires act as sources for the potentials in the form of a sequence of line multipoles with unknown coefficients that are determined by means of conditions arising from the wire surface boundary conditions. Approximations are introduced to relate the local properties of the braid wires to a simplified infinite periodic planar geometry. This is used in a simplified application of reciprocity to be able to treat nonuniform coaxial geometries including eccentric interior coaxial arrangements and an exterior ground plane.

Microwave and Optical Technology Letters

Basilio, Lorena I.; Langston, William L.; Warne, Larry K.; Langston, William L.; Sinclair, Michael B.

In this article, a negative-index metamaterial prism based on a composite unit cell containing a split-ring resonator and a z-dipole is designed and simulated. The design approach combines simulations of a single unit cell to identify the appropriate cell design (yielding the desired negative-index behavior) together with subcell modeling (which simplifies the mesh representation of the resonator geometry and allows for a larger number of resonator cells to be handled). In addition to describing the methodology used to design a n = -1 refractive index prism, results including the effective-medium parameters, the far-field scattered patterns, and the near-zone field distributions corresponding to a normally incident plane-wave excitation of the prism are presented.

2014 USNC-URSI Radio Science Meeting (Joint with AP-S Symposium), USNC-URSI 2014 - Proceedings

Basilio, Lorena I.; Langston, William L.; Warne, Larry K.

The goal of this paper is to define a unit cell containing an electric and magnetic complement and degenerate pair of resonators and subsequently construct a 3-dimensional (3D) n = -1 refractive index prism based upon the final unit cell design. In this effort simulating and observing the response of a negative-index metamaterial (MM) prism to a plane-wave excitation was a primary intent. However, an equally-important goal was to develop an efficient and high-fidelity process for arriving at the prism design.

Warne, Larry K.; Basilio, Lorena I.; Langston, William L.; Chen, Kenneth C.

This report presents analytic transmission line models for calculating the shielding effectiveness of two common calibration standard cables. The two cables have different canonical aperture types, which produce the same low frequency coupling but different responses at resonance. The dominant damping mechanism is produced by the current probe loads at the ends of the cables, which are characterized through adaptor measurements. The model predictions for the cables are compared with experimental measurements and good agreement between the results is demonstrated. This setup constitutes a nice repeatable geometry that nevertheless exhibits some of the challenges involved in modeling non-radio frequency geometries.

PIER B

Langston, William L.; Warne, Larry K.; Chen, Kenneth C.

Abstract not provided.

Warne, Larry K.; Basilio, Lorena I.; Langston, William L.; Salazar, Robert S.; Coleman, Phillip D.; Lucero, Larry M.

This report estimates inductively-coupled energy to a low-impedance load in a loop-to-loop arrangement. Both analytical models and full-wave numerical simulations are used and the resulting fields, coupled powers and energies are compared. The energies are simply estimated from the coupled powers through approximations to the energy theorem. The transmitter loop is taken to be either a circular geometry or a rectangular-loop (stripline-type) geometry that was used in an experimental setup. Simple magnetic field models are constructed and used to estimate the mutual inductance to the receiving loop, which is taken to be circular with one or several turns. Circuit elements are estimated and used to determine the coupled current and power (an equivalent antenna picture is also given). These results are compared to an electromagnetic simulation of the transmitter geometry. Simple approximate relations are also given to estimate coupled energy from the power. The effect of additional loads in the form of attached leads, forming transmission lines, are considered. The results are summarized in a set of susceptibility-type curves. Finally, we also consider drives to the cables themselves and the resulting common-to-differential mode currents in the load.