Publications

@article{nokey,

title = {Conformal Frequency Selective Surfaces for Arbitrary Curvature},

author = {Cesar L. Valle and Gilbert T. Carranza and Raymond C. Rumpf},

url = {https://ieeexplore.ieee.org/abstract/document/9933174/keywords#keywords},

doi = {10.1109/TAP.2022.3216960},

issn = {1558-2221},

year  = {2022},

date = {2022-10-31},

urldate = {2022-10-31},

journal = {IEEE Transactions on Antennas and Propagation},

volume = {71},

issue = {1},

pages = {612-620},

abstract = {An algorithm is introduced for generating frequency selective surfaces (FSS) capable of conforming to any curvature while maintaining proper size, shape and spacing of the elements. Compared to traditional projection and mapping methods, the presented algorithm maintains the electromagnetic properties of the FSS array despite the curvature. The algorithm can be used to conform to radomes, parts of autonomous vehicles, or any surface. The algorithm is agnostic to both element design and surface curvature. This allows the user to design a FSS for any curved surface while maintaining its response comparable to a flat array. The algorithm outputs two standard tessellation language (STL) files, one describing the curved surface and the other the elements of the FSS placed onto the curved surface. This makes the algorithm suitable for 3D printing using systems with more than three axes or for flexible electronics. Several examples of arbitrary surfaces are shown. Lastly, the algorithm was applied to a Jerusalem-cross FSS on a non-symmetrical parabolic dome. The dimensions of the parabolic dome were chosen to test the response of the array on a rather extreme surface against a projected array on the same surface. Simulations were carried out using Ansys HFSS from the infinite array to finite arrays to confirm operation. Three test surfaces were manufactured with measured results found to be in good agreement with simulation.},

keywords = {arbitrary conformal array, conformal frequency selective surface, finite element analysis, frequency selective surface (FSS), gratings, periodic structures, strain, surface fitting},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Design and fabrication of a metalens with a hexagonal array of intersecting-wall meta-atoms for operation in the near-infrared},

author = {Chad L Horton and Stephen M Kuebler and Manuel Martinez and Edgar Bustamante and Raymond C Rumpf and Jimmy Touma},

doi = {10.1109},

year  = {2022},

date = {2022-08-01},

journal = {2022 IEEE Research and Applications of Photonics in Defense Conference (RAPID)},

abstract = {A metalens with a hexagonal array of intersectingwall meta-atoms was designed for operation at a wavelength of 1.550 μm with a new meta-optics design tool (MODT) and fabricated in the photopolymer IP-Dip by multi-photon lithography.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Formulation of Iterative Finite-Difference Method for Generating Large Spatially Variant Lattices},

author = {Manuel F. Martinez and Jesus J. Gutierrez and Jimmy E. Touma and Raymond C. Rumpf},

url = {https://doi.org/10.13052/2022.ACES.J.370201},

year  = {2022},

date = {2022-07-09},

urldate = {2022-02-01},

journal = {ACES Journal},

volume = {37},

number = {2},

issue = {2},

pages = {141-148},

abstract = {A new numerical method to generate  spatially variant lattices (SVLs) is derived and implemented. The algorithm proposed solves the underlying partial differential equations iteratively with an update equation derived using the finite-difference method to obtain an SVL that is continuous, smooth, and free of unintended defects while maintaining the unit cell geometry throughout the lattice.  This iterative  approach is shown to be more memory-efficient when compared to the matrix-based approach and is, thus, suitable for the calculation of large-scale SVLs.  The iterative nature of the solver allows it to be easily implemented in graphics processing unit to parallelize the computation of SVLs. Two spatially variant self-collimating photonic crystals are generated and simulated to demonstrate the functionality of the algorithm as a tool to generate fully three-dimensional photonic devices of realistic size.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Binary-Lens-Embedded Photonic Crystals},

author = {Chun Xia and Edgar Bustamante and Stephen Kuebler and Noel Martinez and Raymond Rumpf and Jimmy Touma},

url = {https://opg.optica.org/viewmedia.cfm?uri=ol-47-12-2943&seq=0},

doi = {https://doi.org/10.6084/m9.figshare.c.6000805.v3},

year  = {2022},

date = {2022-06-02},

urldate = {2022-05-26},

journal = {Optics Letters},

volume = {47},

number = {12},

pages = {2943-2946},

abstract = {A binary-lens-embedded photonic crystal (B-LEPC) was designed for operation at 1550 nm and fabricated by multiphoton lithography. The lens is binary in the sense that optical path difference is generated using unit cells having just two distinct fill factors. The unit cells have a "rod-in-wall" structure that exhibits three-dimensional self-collimation. Simulations show that self-collimation forces light to move through the device without diffracting or focusing, even as the wavefront is reshaped by the lensing region. Upon exiting the device, the curved wavefront causes the light to focus. The thickness of a BLEPC was reduced threefold by wrapping phase in the style of a Fresnel lens. Embedding a faster-varying phase profile enables tighter focusing, and NA = 0.59 was demonstrated experimentally.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {From asymmetrical transmitter to the nonreciprocal isolator using time-varying metasurfaces},

author = {Yaser Khorrami and Davood Fathi and Amin Khavasi and Raymond C. Rumpf },

url = {https://link.springer.com/article/10.1007/s11082-022-03592-0},

year  = {2022},

date = {2022-04-06},

urldate = {2022-04-06},

journal = {Optical and Quantum Electronics},

volume = {54},

number = {268},

abstract = {We present an emulation design method for converting asymmetrical transmitters to nonreciprocal isolators equipped with time-varying metasurfaces. To illustrate the model, we design a structure using a combination of the photonic crystal (PhC) and time-varying metasurface. Moreover, we propose a general approach for numerical analysis of the time-modulated proposed structure using the extension of the transfer matrix method (TMM) which consists of working through the device one layer at a time and calculating an overall transfer matrix including the time-variation of the permittivity and permeability in each layer. Also, we use an optimization algorithm that is less used in the field of electromagnetism but is suitable for fast and accurate parameter optimization. The results show that the proposed method, using pure time-varying metasurfaces which cannot prepare full nonreciprocity alone, is a promising procedure for breaking the Lorentz reciprocity in the general isolator system as well as maintaining the main core of previously asymmetric designed structure.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Cylindrical-lens-embedded photonic crystal based on self-collimation},

author = {Chun Xia and Jesus J. Guitierrez and Stephen M. Kuebler and Raymond C. Rumpf and Jimmy Touma

},

url = {https://doi.org/10.1364/OE.452467},

year  = {2022},

date = {2022-03-14},

urldate = {2022-03-14},

journal = {Optics Express},

volume = {30},

number = {6},

pages = {9165-9180},

abstract = {Photonic crystals can be engineered so that the flow of optical power and the phase of the field are independently controlled. The concept is demonstrated by creating a self-collimating lattice with an embedded cylindrical lens. The device is fabricated in a photopolymer by multi-photon lithography with the lattice spacing chosen for operation around the telecom wavelength of 1550 nm. The lattice is based on a low-symmetry rod-in-wall unit cell that strongly self-collimates light. The walls are varied in thickness to modulate the effective refractive index so light acquires a spatially quadratic phase profile as it propagates through the device. Although the phase of the field is altered, the light does not focus within the device because self-collimation forces power to flow parallel to the principal axes of the lattice. Upon exiting the device, ordinary propagation resumes in free space and the curved phase profile causes the light to focus. An analysis of the experimentally observed optical behavior shows that the device behaves like a thin lens, even though the device is considerably thick.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Printed Circuit Structures: Past, Present and Future},

author = {Raymond C. Rumpf and C. Michael Newton and Kenneth H. Church},

year  = {2022},

date = {2022-01-31},

urldate = {2022-01-31},

journal = {IPC Printed Circuit Structures},

abstract = {Printed Circuit Structures (PCSs) have the potential to revolutionize next generation printed circuit boards (PCBs) and electronics packaging.  Almost every product available today contains sensors, electronics and radios and the growth of the Internet of Things (IoT) is one of the driving forces for this.  The circuits are composed of traces, vias, passive components, active components, antennas and more.  The PCB or flex circuit must then be inserted into or on an object, and if there are multiple circuits, wires are used to electrically connect them, and bolts and glue are used to mechanically secure them.  The extra weight and volume required account for the mismatch in shape and the need to physically access the boards for assembly in the object will often mean the wasted volume for a circuit can be 100 to 1000 times larger than the circuit itself.  PCSs have the potential to eliminate that wasted volume, reduce the weight, and increase the number of electronic functions per volume.  Even more, the third dimension gives more degrees of freedom for circuit design and allows circuits to utilize physics more effectively than planar designs.  We will present a timeline for PCSs, the challenges in software, process and hardware, the advantages, state-of-the-art in PCS today, working demonstrations and the required improvements for PCSs to ultimately exceed the performance of traditional PCBs and flex circuits.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Photon Funnel Design Based on Spatially Variant Self-Collimating Photonic Crystals},

author = {Noel P Martinez and Chun Xia and S. M. Kuebler and Raymond C. Rumpf},

isbn = {978-1-55752-308-2},

year  = {2021},

date = {2021-11-01},

urldate = {2021-11-01},

journal = {Frontiers in Optics + Laser Science 2021},

abstract = {We present a device that flows a beam incident at any position and angle along the input side of a lattice to a single zone at the output. We report the performance of the device.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Dynamical Control of Multilayer Spacetime Structures using Extended Fourier Modal Method},

author = {Khorrami, Yaser and Fathi, Davood and Khavasi, Amin and Rumpf, Raymond},

url = {https://ieeexplore.ieee.org/document/9585376},

doi = {10.1109/JPHOT.2021.3122371},

isbn = {1943-0655},

year  = {2021},

date = {2021-10-26},

urldate = {2021-10-26},

journal = {IEEE Photonics Journal},

abstract = {We introduce two-dimensional space plus time (2D+1) structure and numerically investigate it using a developed multilayer simulation framework, for the first time. The new structure is consisting of crossed grating with time-varying permittivity which is inspired from 1D+1. In this regard, we extend Fourier Modal Method (FMM) in a general approach for spacetime multilayer states. Our proposed framework is fast, robust, and powerful compared to various finite difference methods. We use the scattering matrix technique to develop the proposed spacetime simulation method for multilayer structures using a non-uniform stack of layers. The method is perfectly suitable to investigate the spatiotemporal effects of surfaces/metasurfaces which covers both the transverse electric and magnetic (TE & TM) polarizations. The results show more freedom to control the optical outcomes of the multilayer considering two spatial periodicities in addition to the modulation frequency to reach nonreciprocity as one of the main consequences of the proposed structure. Moreover, we investigate the condition and limitation of breaking the Lorentz rule for spacetime structures. 2D+1 structure is more controllable than the 1D+1 due to its greater ability to adjust spatial manipulation in addition to temporal variations to reach nonreciprocity applications, digital coding, beam steering, etc.},

keywords = {diffractive optics, frequency modulation, gratings, nonhomogeneous media, optical diffraction, optical polarization, optical transmitters, permittivity},

pubstate = {published},

tppubtype = {article}

}

@article{RN155,

title = {Process parameter optimization for removable partial denture frameworks manufactured by selective laser melting},

author = {Seyeon Hwang and Sangsup An and Ubaldo Robles and Raymond C Rumpf},

url = {https://www.sciencedirect.com/science/article/pii/S0022391321002535},

issn = {0022-3913},

year  = {2021},

date = {2021-06-10},

urldate = {2021-06-10},

journal = {The Journal of Prosthetic Dentistry},

abstract = {Selective laser melting (SLM), an additive manufacturing technology, is expected to replace the traditional lost-wax casting process used in producing removable partial denture (RPD) frameworks. However, studies comparing the accuracy of RPD frameworks and the effects of process parameters are lacking.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{RN2,

title = {Wide-band self-collimation in a low-refractive-index hexagonal lattice},

author = {C. Xia and S. M. Kuebler and N. P. Martinez and M. Martinez and R. C. Rumpf and J. Touma},

url = {https://www.osapublishing.org/ol/abstract.cfm?uri=ol-46-9-2228},

doi = {10.1364/ol.421860},

issn = {0146-9592},

year  = {2021},

date = {2021-05-15},

journal = {Opt Lett},

volume = {46},

number = {9},

pages = {2228-2231},

abstract = {Wide-angle, broadband self-collimation (SC) is demonstrated in a hexagonal photonic crystal (PhC) fabricated in a low-refractive-index photopolymer by multiphoton lithography. The PhC can be described as a hexagonal array of cylindrical air holes in a block of dielectric material having a low-refractive index. Optical characterization shows that the device strongly self-collimates light at near-infrared wavelengths that span 1360 to 1610 nm. SC forces light to flow along the extrusion direction of the lattice without diffractive spreading, even when light couples into the device at high oblique angles. Numerical simulations corroborate the experimental findings.},

note = {1539-4794 

Xia, Chun 

Kuebler, Stephen M 

Martinez, Noel P 

Martinez, Manuel 

Rumpf, Raymond C 

Touma, Jimmy 

Journal Article 

United States 

2021/05/01 

Opt Lett. 2021 May 1;46(9):2228-2231. doi: 10.1364/OL.421860.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Wide-band self-collimation in a low-refractive-index hexagonal lattice},

author = {Chun Xia and Stephen M Kuebler and Noel P Martinez and Manuel Martinez and Raymond C Rumpf and Jimmy Touma

},

url = {https://www.osapublishing.org/ol/abstract.cfm?uri=ol-46-9-2228},

doi = {10.1364/OL.421860},

year  = {2021},

date = {2021-05-01},

urldate = {2021-05-01},

journal = {Optics Letters},

volume = {46},

number = {9},

pages = {2228-2231},

abstract = {Wide-angle, broadband self-collimation (SC) is demonstrated in a hexagonal photonic crystal (PhC) fabricated in a low-refractive-index photopolymer by multiphoton lithography. The PhC can be described as a hexagonal array of cylindrical air holes in a block of dielectric material having a low-refractive index. Optical characterization shows that the device strongly self-collimates light at near-infrared wavelengths that span 1360 to 1610 nm. SC forces light to flow along the extrusion direction of the lattice without diffractive spreading, even when light couples into the device at high oblique angles. Numerical simulations corroborate the experimental findings.},

keywords = {hexagonal, multiphoton lithography, photonic crystals, self-collimation},

pubstate = {published},

tppubtype = {article}

}

@article{RN149,

title = {Generating Spatially-Variant Metamaterial Lattices Designed from Spatial Transforms},

author = {Eric A Berry and Raymond C Rumpf},

url = {https://www.jpier.org/PIERM/pierm92/10.19103004.pdf},

issn = {1937-8726},

year  = {2020},

date = {2020-06-01},

journal = {Progress In Electromagnetics Research M},

volume = {92},

pages = {103-113},

abstract = {Spatial transform techniques like transformation optics and conformal mapping have arisen 

as the dominant techniques for designing metamaterial devices. However, these techniques only produce 

the electrical permittivity and permeability as a function of position. The manner in which these 

functions are converted into physical metamaterial lattices remains elusive, except in some simple or 

canonical configurations. Metamaterial lattices designed by spatial transforms are composed of elements 

of different sizes, orientations, and designs. The elements must be distributed and oriented in a manner 

that makes the final lattice smooth, continuous, have uniform density, be free of unintentional defects, 

and have minimal distortions to the elements. Any of these would weaken or destroy the electromagnetic 

properties of the lattice. This paper describes a general purpose method to generate such arbitrary 

metamaterial lattices. Inputs to the algorithm are the permittivity and permeability functions as well 

as the baseline metamaterials that can provide the necessary permittivity and permeability values. 

In prior research, we reported a simple finite-difference technique for calculating the permittivity and 

permeability functions for arbitrary shaped devices using transformation optics. The methodology 

presented in this work is illustrated by generating an electromagnetic cloak of arbitrary shape that 

was designed using the previously reported technique. The final metamaterial cloak is simulated using 

the finite-difference time-domain method and performance compared to other cloaks reported in the 

literature. },

keywords = {conformal mapping, transformation optics},

pubstate = {published},

tppubtype = {article}

}

@article{RN150,

title = {Fast optimal design of optical components using the cultural algorithm},

author = {Yaser Khorrami and Davood Fathi and Raymond C Rumpf},

url = {https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-28-11-15954&id=431742},

doi = {https://doi.org/10.1364/OE.391354},

issn = {1094-4087},

year  = {2020},

date = {2020-06-01},

journal = {Optics express},

volume = {28},

number = {11},

pages = {15954-15968},

abstract = {Design of the guided-mode resonance (GMR) grating filter, as one of the most important optical components, using the cultural algorithm (CA) is presented, for the first time. CA is an evolutionary algorithm (EA) which is easy-to-implement, flexible, inspired by the human cultural evolution, upon using the domain knowledge for reducing the search space as a metaheuristic optimization method. Reflection spectra of the designed GMR filter based on the CA is in good agreement with the previous simulation results. CA has both acceptable accuracy and enough high speed to optimize the complicated structures; therefore, a novel double-line asymmetrical transmitter (DLAT) is introduced and optimized as a complex grating-based optical component using the mentioned algorithm. The results show the transmittance at two different communication wavelengths (1.5039 and 1.6113 µm) using the combination of binary diffraction grating and customized photonic crystal (PhC) structure. Also, the DLAT shows the characteristics of a perfect transverse magnetic (TM) polarizer. Furthermore, we demonstrated the Talbot effect at the DLAT output which is so applicable in the optical usage, especially for the integrated optics.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Fast optimal design of optical components using the cultural algorithm},

author = {Yaser Khorrami and Davood Fathi, and Raymond C. Rumpf



},

url = {https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-28-11-15954&id=431742},

doi = {10.1364/OE.391354},

year  = {2020},

date = {2020-05-13},

urldate = {2020-05-13},

journal = {Optics Express},

volume = {28},

number = {11},

pages = {15954-15968},

abstract = {Design of the guided-mode resonance (GMR) grating filter, as one of the most important optical components, using the cultural algorithm (CA) is presented, for the first time. CA is an evolutionary algorithm (EA) which is easy-to-implement, flexible, inspired by the human cultural evolution, upon using the domain knowledge for reducing the search space as a metaheuristic optimization method. Reflection spectra of the designed GMR filter based on the CA is in good agreement with the previous simulation results. CA has both acceptable accuracy and enough high speed to optimize the complicated structures; therefore, a novel double-line asymmetrical transmitter (DLAT) is introduced and optimized as a complex grating-based optical component using the mentioned algorithm. The results show the transmittance at two different communication wavelengths (1.5039 and 1.6113 µm) using the combination of binary diffraction grating and customized photonic crystal (PhC) structure. Also, the DLAT shows the characteristics of a perfect transverse magnetic (TM) polarizer. Furthermore, we demonstrated the Talbot effect at the DLAT output which is so applicable in the optical usage, especially for the integrated optics.},

keywords = {cultural algorithm, optimization, simulation methods},

pubstate = {published},

tppubtype = {article}

}

@article{RN148,

title = {Guided-mode resonance filter optimal inverse design using one-and two-dimensional grating},

author = {Yaser Khorrami and Davood Fathi and Raymond C Rumpf},

url = {https://www.osapublishing.org/josab/abstract.cfm?uri=josab-37-2-425},

doi = {https://doi.org/10.1364/JOSAB.380094},

issn = {1520-8540},

year  = {2020},

date = {2020-05-01},

journal = {JOSA B},

volume = {37},

number = {2},

pages = {425-432},

abstract = {We propose an optimized method for the inverse design of guided-mode resonance (GMR) filters using one- and two-dimensional (1D and 2D) grating structures. This work for 2D state is based on developing the effective permittivity of 1D grating structures along three orthogonal axes to predict the physical dimensions of the structure, for the first time to our knowledge. Also, we compare three optimization methods to reach the optimized conditions based on the characteristics of multilayer structures. Both the transfer matrix method and rigorous coupled-wave analysis are used to simulate and show the reflection and transmission of the proposed 2D GMR filters. The results show that insensitivity to polarization, the best accuracy in resonance location design, and a high quality factor can be achieved for both the rectangular and cylindrical structures as the ideal 2D GMR filters. Also, the effect of each layer thickness on the resonance location and the full width at half-maximum is illustrated. Finally, we investigate three different reasons for decreasing the FWHM of the output reflection of the GMR filters.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Guided-mode resonance filter optimal inverse design using one-and two-dimensional grating},

author = {Yaser Khorrami and Davood Fathi and Raymond C. Rumpf},

url = {https://www.osapublishing.org/josab/abstract.cfm?uri=josab-37-2-425},

doi = {10.1364/JOSAB.380094},

year  = {2020},

date = {2020-01-23},

urldate = {2020-01-23},

journal = {Journal of the Optical Society of America B},

volume = {37},

number = {2},

pages = {425-432},

abstract = {We propose an optimized method for the inverse design of guided-mode resonance (GMR) filters using one- and two-dimensional (1D and 2D) grating structures. This work for 2D state is based on developing the effective permittivity of 1D grating structures along three orthogonal axes to predict the physical dimensions of the structure, for the first time to our knowledge. Also, we compare three optimization methods to reach the optimized conditions based on the characteristics of multilayer structures. Both the transfer matrix method and rigorous coupled-wave analysis are used to simulate and show the reflection and transmission of the proposed 2D GMR filters. The results show that insensitivity to polarization, the best accuracy in resonance location design, and a high quality factor can be achieved for both the rectangular and cylindrical structures as the ideal 2D GMR filters. Also, the effect of each layer thickness on the resonance location and the full width at half-maximum is illustrated. Finally, we investigate three different reasons for decreasing the FWHM of the output reflection of the GMR filters.},

keywords = {diffraction gratings, guided mode resonance (GMR), inverse design},

pubstate = {published},

tppubtype = {article}

}

@article{RN145,

title = {High-Frequency Filters Manufactured Using Hybrid 3D Printing Method},

author = {Ubaldo Robles and Edgar Bustamante and Prya Darshni and Raymond C Rumpf},

url = {https://www.jpier.org/PIERM/pier.php?paper=18102603},

issn = {1937-8726},

year  = {2019},

date = {2019-08-27},

journal = {Progress In Electromagnetics Research},

volume = {84},

pages = {147-155},

abstract = {In this work, two different high-frequency filters were produced, and each was manufactured in two different ways, one using conventional PCB technology and the other using hybrid 3D printing. The hybrid 3D printing technique combined the use of microdispensing of conductive inks and fused filament fabrication (FFF) of thermoplastic substrates. Measurements, properties, and comparisons between these filters are discussed. The goal of the research was to benchmark 3D printing of high-frequency filters to more confidently manufacture sophisticated devices and high-frequency systems by hybrid 3D printing.},

keywords = {high-frequency filters, hybrid 3D printing},

pubstate = {published},

tppubtype = {article}

}

@article{RN144,

title = {Independent control of phase and power in spatially variant self-collimating photonic crystals},

author = {Jesus J Gutierrez and Noel P Martinez and Raymond C Rumpf},

issn = {1520-8532},

year  = {2019},

date = {2019-05-01},

journal = {JOSA A},

volume = {36},

number = {9},

pages = {1534-1539},

abstract = {Self-collimating photonic crystals are a promising technology to control waves in optical devices. A technique was recently developed that can bend, twist, and otherwise spatially vary a photonic crystal without deforming the unit cells, as this would weaken or destroy the optical properties. Applying this to self-collimating photonic crystals allows us to control multiple properties of light at the same time. A spatially variant self-collimating photonic crystal is shown that decouples the phase and power of the wave and controls them independently and at the same time within the same volume. This creates new physical mechanisms from which to design optical systems. Some possible applications include miniaturization of optical},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{RN141,

title = {Automated hybrid 3-D printing of 3-D meandering interconnects},

author = {Ubaldo Robles and Andelle Kudzal and Raymond C Rumpf},

url = {https://ieeexplore.ieee.org/document/8689070/keywords#keywords},

doi = {10.1109/TCPMT.2019.2909979},

issn = {2156-3950},

year  = {2019},

date = {2019-04-12},

urldate = {2019-04-12},

journal = {IEEE Transactions on Components, Packaging and Manufacturing Technology},

volume = {9},

number = {6},

pages = {1184-1189},

abstract = {In this paper, a completely automated computeraided design (CAD)-to-print process flow for hybrid direct-write 3-D printing (3DP) was produced. We adapted this capability to manufacture a meandering conductive trace formed into a meandering arbitrary interconnect in the shape of a 3-D pretzel that is completely embedded in dielectric. The conversion between g-code and pgm-code was demonstrated for hybrid 3DP between metal and dielectric materials. This paper produced a reliable automated process that can potentially be used to manufacture arbitrary 3-D circuits. This paper also identified the need for better slicing techniques for hybrid manufacturing of interconnects.},

keywords = {3D printing},

pubstate = {published},

tppubtype = {article}

}

@article{RN137,

title = {Design and hybrid additive manufacturing of 3-D/volumetric electrical circuits},

author = {Gilbert T Carranza and Ubaldo Robles and Cesar L Valle and Jesus J Gutierrez and Raymond C Rumpf},

url = {https://ieeexplore.ieee.org/document/8610012},

doi = {10.1109/TCPMT.2019.2892389},

issn = {2156-3950},

year  = {2019},

date = {2019-01-11},

journal = {IEEE Transactions on Components, Packaging and Manufacturing Technology},

volume = {9},

number = {6},

pages = {1176-1183},

abstract = {For the first time, a fully 3-D electric circuit was modeled in a 3-D environment and manufactured via an automated hybrid direct-write 3-D printing process. The implications and applications of this significant achievement are enormous because it allows circuits to be designed and manufactured in virtually any form factor. To accomplish this, a custom computer-aided design (CAD) tool was programmed into an open-source modeling software to layout components and route interconnects. The custom CAD tool imports the netlist and component geometries from a schematic capture program. Components can be placed at any position and be oriented at any angle. Interconnects can meander smoothly throughout the circuit following 3-D splines. The interconnects can be placed manually or automatically between components. After laying out the components and routing interconnects, the tool exports Standard Tessellation Language files of the dielectric and metal portions of the final circuit to be 3-D printed. To manufacture the circuit, fused-deposition modeling of acrylonitrile butadiene styrene plastic and microdispensing (μD) of DuPont CB028 silver paste was used. To demonstrate, a functional 555 timer circuit was designed and built to flash an LED.},

keywords = {circuit design, circuit design, electronics packaging, FDM, fused deposition modeling, hybrid 3D printing, microdispensing, printed circuit, signal routing},

pubstate = {published},

tppubtype = {article}

}

@article{RN131,

title = {3-d printed structures by microdispensing materials loaded with dielectric and magnetic powders},

author = {Ubaldo Robles and Justin Kasemodel and Jose Avila and Tenoch Benitez and Raymond C Rumpf},

url = {https://ieeexplore.ieee.org/document/8263403},

doi = {10.1109/TCPMT.2017.2781723},

issn = {2156-3950},

year  = {2018},

date = {2018-03-01},

urldate = {2018-03-01},

journal = {IEEE Transactions on Components, Packaging and Manufacturing Technology},

volume = {8},

number = {3},

pages = {492-498},

abstract = {In this paper, we develop processes for printing 3-D structures by microdispensing materials loaded with dielectric and magnetic powders. Manufacturing with these materials is demonstrated by 3-D printing simple tower and bridge structures. The dielectric and magnetic properties are adjusted by loading different amounts of powder into a host silicone material. The long-term goal of the research is to print larger and more complex structures while also realizing a range of electromagnetic properties for applications in 3-D printed electromagnetics.},

keywords = {3D printing, dielectrics, magnetic properties, microdispensing},

pubstate = {published},

tppubtype = {article}

}

@article{RN123,

title = {Optimization and Characterization of Negative Uniaxial Metamaterials},

author = {Jose Avila and Cesar L Valle and Edgar Bustamante and Raymond C Rumpf},

url = {https://www.jpier.org/pierc/pier.php?paper=17030906},

doi = {doi:10.2528/PIERC17030906},

issn = {1937-8718},

year  = {2017},

date = {2017-05-23},

urldate = {2017-05-23},

journal = {Progress In Electromagnetics Research C},

volume = {74},

pages = {111-121},

abstract = {Digital manufacturing, or 3D printing, is a rapidly emerging technology that enables novel designs that incorporate complex geometries and even multiple materials. In electromagnetics and circuits, 3D printing allows the dielectrics to take on new and profound functionality. This paper introduces negative uniaxial metamaterials (NUMs) which are birefringent structures that can be used to manipulate electromagnetic fields at a very small scale. The NUMs presented here are composed of alternating layers of two different dielectrics. The physics of the NUMs are explained and simple analytical equations for the effective dielectric tensor are derived. Using these equations, the NUMs are optimized for strength of anisotropy and for space stretching derived from transformation optics. The analytical equations are validated through rigorous simulations and by laboratory measurements. Three NUMs where manufactured using 3D printing where each exhibited anisotropy in a different orientation for measurement purposes. All of the data from the analytical equations, simulations, and experiments are in excellent agreement confirming that the physics of the NUMs is well understood and that NUMs can be designed quickly and easily using just the analytical equations.},

keywords = {birefringent, dielectrics, hybrid 3D printing, negative uniaxial metamaterials},

pubstate = {published},

tppubtype = {article}

}