Publications

@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{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{RN109,

title = {Ultra-thin 3D printed all-dielectric antenna},

author = {Carlos Rodriguez and Jose Avila and Raymond C Rumpf},

url = {https://www.jpier.org/PIERC/pier.php?paper=16020602},

doi = {doi:10.2528/PIERC16020602},

issn = {1937-8718},

year  = {2016},

date = {2016-05-26},

journal = {Progress In Electromagnetics Research C},

volume = {64},

pages = {117-123},

abstract = {In this work we report an ultra-thin all-dielectric antenna that was designed, built, tested, and compared with simulated data. The objective of this research was to develop an antenna that is easily manufactured by common 3-D printers available today. 3-D printing is quickly revolutionizing manufacturing and the need to incorporate electrical elements like antennas is rising. Multi-material 3-D printing that can build parts with conductors and dielectrics is the future, but at present it is very immature and largely inaccessible. The antenna presented here represents our first steps in developing all-dielectric antennas that can be manufactured today with commonly available 3-D printers and materials. A monolithic antenna would have additional mechanical benefits when subjected to bending or thermal cycling. With this goal in mind, an ultra-thin all-dielectric antenna was developed. The antenna operates by taking advantage of total internal reflection and exciting a leaky whispering gallery mode. The antenna reported here operates at 2.4 GHz and was able to be as thin as 1.5 mm.},

keywords = {3D printing, all-dielectric antenna, hybrid 3D printing},

pubstate = {published},

tppubtype = {article}

}

@article{RN100,

title = {Thermo-mechanical characterization of metal/polymer composite filaments and printing parameter study for fused deposition modeling in the 3D printing process},

author = {Seyeon Hwang and Edgar I Reyes and Kyoung-sik Moon and Raymond C Rumpf and Nam Soo Kim},

url = {https://link.springer.com/content/pdf/10.1007%2Fs11664-014-3425-6.pdf},

doi = {DOI: 10.1007/s11664-014-3425-6},

issn = {1543-186X},

year  = {2014},

date = {2014-10-29},

journal = {Journal of Electronic Materials},

volume = {44},

number = {3},

pages = {771-777},

abstract = {New metal/polymer composite filaments for fused deposition modeling (FDM) 

processes were developed in order to observe the thermo-mechanical properties of the new filaments. The acrylonitrile butadiene styrene (ABS) thermoplastic was mixed with copper and iron particles. The percent loading of the 

metal powder was varied to confirm the effects of metal particles on the 

thermo-mechanical properties of the filament, such as tensile strength and 

thermal conductivity. The printing parameters such as temperature and fill 

density were also varied to see the effects of the parameters on the tensile 

strength of the final product which was made with the FDM process. As a 

result of this study, it was confirmed that the tensile strength of the composites is decreased by increasing the loading of metal particles. Additionally, 

the thermal conductivity of the metal/polymer composite filament was improved by increasing the metal content. It is believed that the metal/polymer 

filament could be used to print metal and large-scale 3-dimensional (3D) 

structures without any distortion by the thermal expansion of thermoplastics. 

The material could also be used in 3D printed circuits and electromagnetic 

structures for shielding and other applications.},

keywords = {3D printing, copper, fused deposition modeling, iron, large-scale 3D  printing, Metal/polymer composite filament, thermo-mechanical properties},

pubstate = {published},

tppubtype = {article}

}

@article{RN77,

title = {Effects of extreme surface roughness on 3D printed horn antenna},

author = {CR Garcia and RC Rumpf and HH Tsang and JH Barton},

url = {https://ietresearch.onlinelibrary.wiley.com/doi/10.1049/el.2013.1528},

doi = {https://doi.org/10.1049/el.2013.1528},

issn = {1350-911X},

year  = {2013},

date = {2013-06-01},

journal = {Electronics letters},

volume = {49},

number = {12},

pages = {734-736},

abstract = {3D printing is an emerging technology in manufacturing. It is the long-term goal of the industry to print complex and fully functional products from cell phones to vehicles. A drawback of many 3D printing technologies is rough surface finish. It is known that metals with high surface roughness severely degrade the propagation of electromagnetic waves. Presented is the first known evaluation of the electromagnetic impact of the typical surface roughness in metal parts produced by electron beam melting. Two Ku-band (12–15 GHz) horn antennas were 3D printed, with different surface roughness, and compared to a standard horn antenna purchased from Pasternack.},

keywords = {3D printing, electron beam melting, surface finish, surface roughness},

pubstate = {published},

tppubtype = {article}

}

@article{RN70,

title = {3D printed lattices with spatially variant self-collimation},

author = {Raymond C Rumpf and Javier Pazos and Cesar R Garcia and Luis Ochoa and Ryan Wicker},

url = {https://www.jpier.org/PIER/pier139/01.13030507.pdf},

issn = {1070-4698},

year  = {2013},

date = {2013-01-01},

journal = {Progress In Electromagnetics Research},

volume = {139},

pages = {1-14},

abstract = {In this work, results are given for controlling waves arbitrarily inside a lattice with spatially variant self-collimation. To demonstrate the concept, an unguided beam was made to flow around a 90 deg bend without scattering due to the bend or the spatial variance. Control of the field was achieved by spatially varying the orientation of the unit cells throughout a self-collimating photonic crystal, but in a manner that almost completely eliminated deformations to the size and shape of the unit cells. The device was all-dielectric, monolithic, and made from an ordinary dielectric with low relative permittivity (εr = 2.45). It was manufactured by fused deposition modeling, a form of 3D printing, and its performance confirmed experimentally at 

around 15 GHz.},

keywords = {3D printing, self-collimation, spatially variant},

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}

}