Publications

@article{RN102,

title = {Spatially variant periodic structures in electromagnetics},

author = {Raymond C Rumpf and Javier J Pazos and Jennefir L Digaum and Stephen M Kuebler},

url = {https://royalsocietypublishing.org/doi/full/10.1098/rsta.2014.0359},

doi = {https://doi.org/10.1098/rsta.2014.0359},

issn = {1364-503X},

year  = {2015},

date = {2015-08-28},

journal = {Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences},

volume = {373},

number = {2049},

pages = {20140359},

abstract = {Spatial transforms are a popular technique for designing periodic structures that are macroscopically inhomogeneous. The structures are often required to be anisotropic, provide a magnetic response, and to have extreme values for the constitutive parameters in Maxwell's equations. Metamaterials and photonic crystals are capable of providing these, although sometimes only approximately. The problem still remains about how to generate the geometry of the final lattice when it is functionally graded, or spatially varied. This paper describes a simple numerical technique to spatially vary any periodic structure while minimizing deformations to the unit cells that would weaken or destroy the electromagnetic properties. New developments in this algorithm are disclosed that increase efficiency, improve the quality of the lattices and provide the ability to design aplanatic metasurfaces. The ability to spatially vary a lattice in this manner enables new design paradigms that are not possible using spatial transforms, three of which are discussed here. First, spatially variant self-collimating photonic crystals are shown to flow unguided waves around very tight bends using ordinary materials with low refractive index. Second, multi-mode waveguides in spatially variant band gap materials are shown to guide waves around bends without mixing power between the modes. Third, spatially variant anisotropic materials are shown to sculpt the near-field around electric components. This can be used to improve electromagnetic compatibility between components in close proximity.},

keywords = {fuctionally graded, metamaterials, metasurfaces, optics, photonic crystals, physiological optics, spatially variant, transformation optics},

pubstate = {published},

tppubtype = {article}

}

@article{RN45,

title = {3D printing of anisotropic metamaterials},

author = {Cesar R Garcia and Jesus Correa and David Espalin and Jay H Barton and Raymond C Rumpf and Ryan Wicker and Virgilio Gonzalez},

url = {https://www.jpier.org/PIERL/pierl34/08.12070311.pdf},

issn = {1937-6480},

year  = {2012},

date = {2012-01-01},

journal = {Progress In Electromagnetics Research Letters},

volume = {34},

pages = {75-82},

abstract = {—Material properties in radio frequency and microwave 

regimes are limited due to the lack of molecular resonances at these 

frequencies. Metamaterials are an attractive means to realize a 

prescribed permittivity or permeability function, but these are often 

prohibitively lossy due to the use of inefficient metallic resonators. 

All-dielectric metamaterials offer excellent potential to overcome these 

losses, but they provide a much weaker interaction with an applied 

wave. Much design freedom can be realized from all-dielectric 

structures if their dispersion and anisotropy are cleverly engineered. 

This, however, leads to structures with very complex geometries 

that cannot be manufactured by conventional techniques. In this 

work, artificially anisotropic metamaterials are designed and then 

manufactured by 3D printing. The effective material properties are 

measured in the lab and agree well with model predictions.},

keywords = {3D printing, all-dielectric structures, metamaterials},

pubstate = {published},

tppubtype = {article}

}