Robert Christopher Roberts

Robert Christopher Roberts
University of Texas at El Paso | UTEP · Department of Electrical and Computer Engineering

Ph.D.

About

52
Publications
14,903
Reads
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672
Citations
Additional affiliations
January 2019 - present
University of Texas at El Paso
Position
  • Professor (Assistant)
July 2018 - December 2018
The University of Hong Kong
Position
  • Lecturer
July 2017 - June 2018
The University of Hong Kong
Position
  • Research Associate

Publications

Publications (52)
Article
Full-text available
Diabetes is a major public health challenge affecting more than 451 million people. Physiological and experimental factors influence the accuracy of non-invasive glucose monitoring, and these need to be overcome before replacing the finger prick method. Also, the suitable employment of machine learning techniques can significantly improve the accur...
Article
This paper deals with the fabrication and unconstrained dielectric transfer of 3D printed metal components demonstrated using an electrostatic micro switch. The use of micro laser sintering (MLS) to print micro-electro-mechanical systems (MEMS) enables a new MEMS fabrication capability able to bypass conventional high-cost fabrication processes for...
Conference Paper
Introduction to Electrical Engineering (I2EE) is one of the core courses offered to freshmen in the Electrical and Computer Engineering department at the University of Texas at El Paso (UTEP). The purpose of this course is introducing students to theoretical and practical concepts those form the basis for electrical engineering. Hands-on lab module...
Article
High‐resolution 3D‐printed stainless steel metal microreactors (3D‐PMRs) with different cross‐sectional geometry are fabricated to control ultrafast intramolecular rearrangement reactions in a comparative manner. The 3D‐PMR with circular channel demonstrates the improved controllability in rapid Fries‐type rearrangement reactions, because of the su...
Article
Full-text available
In this letter, we present a wideband planar antenna with on-demand band-rejected characteristics based on the peelable double Electric-LC (DELC) resonator membranes. By applying microfabrication techniques, the subwavelength DELC structure is completely encapsulated in a transparent and flexible thin film with a total thickness of 10 um. Resonator...
Article
Since 2002, the IEEE Sensors Conference has been held in a different country every year during the last two decades, keeping a tradition of going to different geographical regions of IEEE. During this time, the IEEE Sensors Conference has become one of the premier global events on sensors and addressing the whole range from principles, design and f...
Article
Full-text available
This paper presents a fifth-order W-band waveguide bandpass filter with a Chebyshev response, operating at center frequency of 90 GHz and having fractional bandwidth of 11%. The filter is fabricated by micro laser sintering process which is a powder bed based additive manufacturing technology. Use of this technology allows the filter to be made acc...
Article
Full-text available
We demonstrate a ventilated metamaterial absorber operating at low frequency (<500 Hz). With only two layers of absorption units, high-efficiency absorption (>90%) has been achieved in both simulations and experiments. This high-efficiency absorption under the ventilation condition originates from the weak coupling of two identical split tube reson...
Preprint
We demonstrate a ventilated metamaterial absorber operating at low frequency. By employing only two layers of the absorption units, high-efficiency absorption is achieved in simulations (> 90%) and experiments (> 80%) at maximum absorption. This high-efficiency absorption is originated from the weak coupling of the two identical split tube resonato...
Poster
Full-text available
Poster contains further findings in addition to the journal publication in Scientific Reports.
Article
Full-text available
An efficient technique for writing 2D oxide patterns on conductive substrates is proposed and demonstrated in this paper. The technique concerns a novel concept for selective electrodeposition, in which a minimum quantity of liquid electrolyte, through an extrusion nozzle, is delivered and manipulated into the desired shape on the substrate, meanwh...
Article
Unlabelled: A pressure sensor based on irregular microhump patterns has been proposed and developed. The devices show high sensitivity and broad operating pressure regime while comparing with regular micropattern devices. Finite element analysis (FEA) is utilized to confirm the sensing mechanism and predict the performance of the pressure sensor b...
Conference Paper
Full-text available
This paper reports on the design and fabrication of buckled metal strain gauges formed using a thermally contracting shape memory polymer (SMP) via inkjet printed silver nanoparticles to create sensors realized in a large initial compressive stress state. Printed devices are placed into an oven to simultaneously sinter the nanoparticles and shrink...
Article
In this work, we investigate the coalescence of emulsion droplets in a controlled electric field. Two contacting droplets stabilized by surfactants can be forced to coalesce into a combined one when the applied voltage is above a critical value. The critical voltages change with the types, concentrations of surfactants and temperature. By exploring...
Article
Full-text available
This paper reports on a simple 3D metal electrode fabrication technique via inkjet printing onto a thermally contracting shape memory polymer (SMP) substrate. Inkjet printing allows for the direct patterning of structures from metal nanoparticle bearing liquid inks. After deposition, these inks require thermal curing steps to render a stable conduc...
Article
Microfluidic systems based on polydimethylsiloxane (PDMS) have gained their popularity in recent years. However, microelectrodes patterning on PDMS to form biosensors in microchannels remains a worldwide technical issue due to the hydrophobicity of PDMS and its weak adhesion to metals. In this study, an additive technique using inkjet printed silve...
Conference Paper
Full-text available
A simple and effective metal patterning technique on polydimethylsiloxane (PDMS) using inkjet printed silver nanoparticles with a (3-mercaptopropyl) trimethoxysilane (MPTMS) adhesion promoter to form silver microelectrodes for microfluidic systems is presented. Inkjet printing is an alternative additive microfabrication technique enabling the possi...
Conference Paper
Inkjet-printed metal nanoparticles have been intensively studied for microelectronic applications including both physical and chemical sensors, and micro-electro- mechanical systems (MEMS). However, printed feature broadening is frequently observed due to the coalescence of un- dried ink, reducing achievable resolution. Increasing substrate tempera...
Conference Paper
Full-text available
A novel direct method of metal microelectrode patterning on polydimethylsiloxane (PDMS) using inkjet printed gold and silver nanoparticles to form electrochemical sensors is presented. Inkjet printing is an additive microfabrication technique enabling microelectrode patterning directly over large areas at low-temperatures. (3-mercaptopropyl) trimet...
Article
Full-text available
The fabrication of electronic circuits on unconventional substrates largely broadens their application areas. For example, green electronics achieved through utilization of biodegradable or recyclable substrates, can mitigate the solid waste problems that arise at the end of their lifespan. Here, we combine screen-printing, high precision laser dri...
Article
A passive chipless radio-frequency identification (RFID) tag based on a log-periodic (LP) dipole array is proposed, where the tailorable band-rejection property of the LP aperture is utilised to realise a large number of codes. The proposed tag principle is successfully validated by measurements, where the absence and presence of the band-rejection...
Article
A passive chipless Radio-frequency identification (RFID) tag based on log-periodic (LP) dipole array is proposed, where the tailorable band-rejection property of the LP aperture is utilized to realize large number of codes. The proposed tag principle is successfully validated using measurements, where the absence and presence of the band-rejection,...
Conference Paper
Full-text available
We report a bi-material additive microfabrication technique combining inkjet-printed gold films and an aerosol-deposited dielectric enamel for the realization of multilayer microsystems. Hexanethiol-encapsulated gold nanoparticle ink enables metal deposition at atmospheric pressure with a maximum temperature of 200°C. Dielectric patterning is achie...
Conference Paper
Full-text available
This paper presents the thermoresistive characteristics of hexanethiol encapsulated gold nanoparticles (NPs), inkjet printed onto Corning 0215 glass and sintered in air. The use of organic encapsulated metal NP precursors enables the growing field inkjet printed microsystems to build low-cost sensors and actuators on non-traditional substrates. How...
Article
A novel microfluidic system which is fabricated with five polydimethylsiloxane layers for interstitial fluid (ISF) extraction, collection, and measurement toward the application of continuous and real-time glucose monitoring is presented in this paper. The system consists of a micro vacuum generator for ISF transdermal extraction and fluid manipula...
Article
Transdermal extraction of interstitial fluid (ISF) offers an attractive method for non-invasive blood glucose monitoring. In order to calculate blood glucose concentration accurately, precise volume measurement of transdermally extracted ISF is required due to human skin’s varying permeability. In this paper, we presented a novel flow sensor fabric...
Article
Transdermal extraction of interstitial fluid (ISF) offers an attractive method for noninvasive blood glucose monitoring. The existing macroscale systems are not suitable for ISF collection, mainly because of the minute volume of the transdermally extracted ISF which scatters on the skin surface. Human skin's low permeability to glucose and its vary...
Article
Full-text available
In this paper, a micro-Venturi tube fabricated with polydimethylsiloxane (PDMS) is studied for interstitial fluid (ISF) transdermal extraction and fluid manipulation in a microfluidic system toward the application of continuous glucose monitoring. The fabrication structure parameters of the PDMS Venturi tube were theoretically analyzed and experime...
Article
We present a new microfluidic system for transdermal interstitial fluid (ISF) extraction, collection, and volumetric measurement towards the application of continuous glucose monitoring. This device consists of a venturi tube, a volume sensor, pneumatic valves, and microchannels. Under the management of pneumatic valves, demonstration of the define...
Article
We report on experimental demonstration of a new type of nanomechanical resonators based on very thin silicon carbide (SiC) square membranes. An optical interferometry with a radio-frequency two-port measurement scheme enables sensitive and efficient detection of many vibrational modes of the membranes. Membranes with sizes up to 1mm × 1mm and thic...
Chapter
Full-text available
This chapter presents an overview of the key methods and process recipes commonly employed in the deposition of semiconductor and dielectric thin films used in the fabrication of microelectromechanical systems (MEMS). These methods include chemical vapor deposition, epitaxy, physical vapor deposition, atomic layer deposition, and spin-on techniques...
Article
Full-text available
We present a new microfluidic system for transdermal interstitial fluid (ISF) extraction, collection, and volumetric measurement towards the application of noninvasive, continuous, and real-time glucose monitoring. This device consists of a Venturi Tube for vacuum generation, chambers for the introduction of ISF and normal saline solution, pneumati...
Article
Full-text available
We present a microfluidic volumetric measurement system for applications involving conductive fluids. The low cost polydimethylsiloxane (PDMS) device consists of an interconnected Venturi Tube to generate vacuum for fluid manipulation, and a resistance based sensor for fluid volume quantification. The Venturi Tube achieves less than 88 kPa (absolut...
Conference Paper
Full-text available
This work presents a microfabricated differential mode capacitive gas sensor utilizing temperature compensation. Typical capacitive cantilever sensors offer promise of both high sensitivity and large measurement range. Unfortunately, functionalized cantilevers form a bimorph system, creating a temperature dependence due to the stress gradient induc...
Conference Paper
We present a microfluidic based interstitial fluid (ISF) transdermal extraction tool fabricated from polydimethylsiloxane (PDMS), designed towards the application of continuous glucose monitoring. This device consists of a Venturi Tube for vacuum generation, chambers for the introduction of ISF and normal saline solution, pneumatic valves for fluid...
Conference Paper
Full-text available
The 21<sup>st</sup> century requires innovative solutions to meet the ever increasing demand for ultra portable and highly efficient energy technologies. Micro-electro-mechanical Systems (MEMS) have shown significant promise in providing robust, low-cost transduction capabilities. MEMS sensors and actuators are ideally suited for small-scale energy...
Article
This paper reports on corona discharge needle-to- plane configurations to act as ionizers for airborne particulate analysis applications. Three electrode configurations are explored with the objective of obtaining a high electric field strength to maximize the probability that all incoming particles are ionized. The hybrid FE-Trefftz method, which...
Conference Paper
Full-text available
This paper reports that the forces needed to break Al and Cu native oxide are 0 to 3 muN, and 0 to 0.5 muN, respectively, remarkably less than the previously reported 0.1 N force requirement of breaking Al native oxide. Our modeling and experimental results indicate that nanoscale contact resistance is dominated by local hardening instead of contac...
Conference Paper
Full-text available
A novel minimally invasive way to measure blood glucose concentration is proposed by combining interstitial fluid (ISF) transdermal extraction and surface plasmon resonance (SPR) detection. 55 kHz low-frequency ultrasound pulses are applied for 30 seconds to enhance the skin permeability and then interstitial fluid is extracted out of skin by vacuu...

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Projects

Projects (2)
Project
Development of an efficient and simple approach for additive microfabrication of ceramic/metallic structure with local electrodeposition as the method, and metallic actuators based on electrochemical transition between nickel oxy-hydroxide and nickel hydroxide.