Thomas P. Weldon, Ph.D., P.E., Email:
Research Projects

Areas of expertise:
Metamaterials and Digital Non-Foster Elements and Radio Systems and RFIC
Signal and Image Processing and Embedded Signal Processing
iPhone Apps and Objective-C , and Java, NetBeans, and C++.
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Publications and Patents:

Links to my Papers/Publications and US Patents

Research Projects:

Research on Digital Non-Foster Circuits for antennas, metamaterials, ...and more. See papers: `` Performance of Digital  Discrete-Time Implementations of Non-Foster Circuit Elements,'' and ``Stability Conditions for a Digital Discrete-Time Non-Foster Circuit Elements.'' and Two-Port Digital Non-Foster paper. Non-Foster circuits such as negative capacitors and negative inductors offer the potential for significantly improved bandwidths in creating smaller antennas and better metamaterials.  These devices also have potential in other applications such as cancellation of stray capacitance and mitigation of inductive wiring. See our metamaterials project website for recent results, papers, and patents.

Research on Wideband Metamaterials. Metamaterials have tremendous potential in applications such as space-time history editors, negative refraction, superlenses, and invisibility cloaks. However, metamaterials tend to have narrow bandwidth due to the resonant nature of components such as split rings. Recently, we have developed theory for new wideband metamaterials using digital discrete-time non-Foster devices.  See our metamaterial project website for recent results, papers, and patents.

Research on High-speed Embedded Digital Signal Processing (DSP) using NXP LPC4370 Cortex-M4 ARM MCU and Freescale FRDM-K64F.  We are currently pursuing patent-pending techniques for novel digital signal processing methods.  See the simple NXP LPC4370 tutorial and a brief introduction to programming the ARM Cortex-M4-based NXP LPC4370 MCU using the LPCXpresso IDE and using two LPC-Link2 development board. See also my Embedded Signal Processing course for other MCUs such as the Freescale FRDM-K64F.

Research on Metamaterials, Quantum Gravity, and the Search for the Missing Half of Maxwell's Equations. Although metamaterials may seem unrelated to gamma-ray astrophysics and quantum gravity, it is shown that these phenomena may be expressed using left-handed extensions to Maxwell's equations. The results are based on measured data that show GeV gamma rays arriving much later than low-energy photons. The equations exhibit right-handed low-frequency behavior and left-handed high-frequency behavior. See our IEEE International Microwave Symposium 2011 paper . More recently, we present Gaussian Models for Observed Dispersion in High Redshift Gamma Ray Bursts , where measured GeV time delays are predicted using the Hubble constant and cosmological constants, and where superluminal effects are avoided.

Research on iPhone-based systems. Advances in smartphone technology offer the potential for a wide variety of new applications that make use of the mobile computing power and wireless communication capability of these devices. See new project-based course on iPhone-based systems where students create novel applications and systems that take advantage of the latest smartphone technology .

Research on Segmentation of OCT Images of the Cavernous Nerves of the Prostate Gland to help prevent risk of injury during surgical removal of cancer. This work was cited as "Feature of the Week" in the Oct. 3, 2010 edition of Optical Coherence Tomography News The proposed image processing system uses a combination of segmentation, denoising, and edge detection algorithms to segment time-domain optical coherence tomography (OCT) images of the prostate to improve identification of cavernous nerves. See 2010 Journal of Biomedical Optics paper and also see 2009 Journal of Biomedical Optics paper.

Research on an N-ary Morphological Operator for removal of image segmentation boundary errors. See recent applications of our N-ary morphology methods to detection of breast cancer (2010) and to prostate imaging (2010). The proposed N-ary morphological operator resembles a binary erosion and dilation for N-ary images. See our paper describing the proposed N-ary Morphological Operator.

Research on Single-Chip Frequency-Synthesized Radio Frequency Spectrum Analyzer incorporating a Successive Detection Log Video Amplifier. This work is targeted at cognitive radio applications, where next-generation radio systems will have to measure and adapt to the local frequency spectrum. See recent paper on Single-Chip Frequency-Synthesized Radio Frequency Spectrum Analyzer. Also, see a related paper on a Detector Log Video Amplifier paper.

Research on Left-Handed Extensions of Maxwell's Equations for Metamaterials. Left-handed metamaterials are commonly analyzed by using frequency-dependent parameters for negative permittivity and negative permeability. An alternative approach is presented where both right-handed and left-handed behavior are supported by augmenting Maxwell's equations with constant parameters and additional terms. See Left-Handed Extensions of Maxwell's Equations. and a related paper A Delay Line Discriminator for IFM Using a Left-Handed Delay Line.

Tutorial on Cadence and Agilent ADS RFIC Design . A tutorial on using Agilent ADS and Cadence to design RFIC's (Radio Frequency Integrated Circuits). Schematic entry and simulation are done in Agilent ADS, and integrated circuit layout is done in Cadence. (Primarily for my radio frequency design courses.)

Research on Rayleigh/Mie Ehnancement of Blackbody Radiation in Nanoscale Devices to shape the spectrum of blackbody radiation by suppressing blackbody emission at long wavelength and enhancing blackbody radiation at short wavelength. The basic notion is the creation of a "better light bulb" by suppressing heat loss (infrared emission) and by enhancing visible light emission. See recent paper on Rayleigh/Mie Ehnancement of Blackbody Radiation.

Research on "serious games." Video games and game engines can be used to develop educational games, to train employees and emergency personnel, to manipulate or visualize data, to simulate robotic systems, and to prototype complex systems. See a simple Space Shuttle game-based simulator, and my Advanced Computer Graphics course.

Research on patented "super-linear transistors" for wireless RF integrated circuits (RFIC) consisting of a PMOS FET in parallel with an NMOS FET. (see patents below)
IEEE RFIC 2005 paper on "super-linear transistors."

Java/Netbeans tutorial added. Quick tutorial on how to use Java/Netbeans to create an program to display images, write files, paint, etc. See also example Java/Netbeans program ImgProJv41 and a simple Introduction to UNIX and C++.

Research on patented linearization methods for wireless RF integrated circuits (RFIC). See 2009 paper on 4-stage methods and US 6,794,938 patent cover sheet and US 6,794,938 full patent for linearization methods, IEEE IMS 2003 paper on linearization methods and a recent thesis on these linearization methods.

Research on patented Built-In Self-Test (BIST) methods for digital circuits including SRAM. In particular: 1) digital circuits are tested with voltages between normal logic level voltages, and 2) digital circuits are tested by inducing controlled-width power supply current pulses (controlled-Iddt).
US 6,833,724 patent cover sheet and US 6,833,724 full patent for BIST.

Research on a mixed-signal fault simulator for mixed-signal Built-In Self-Test (BIST)
Sponsored by DARPA NeoCAD project, and managed by Sensors Directorate of the Air Force Research Laboratory, USAF, Wright-Patterson AFB.

RF / Wireless Engineering Laboratory for radio frequency and microvave systems and devices. Click on the image to the left to find more information about this topic.

The development of Mixed-signal Integrated Circuits and design tools. Click on the image to the left to find more information about this topic.

Agilent ADS design software lab for radio frequency design. Click on the image to the left to find more information about this topic.

Ground penetrating radar (GPR) paper .

An image texture-segmentation program called teXan. Click on the image to the left to find more information about this topic.

A general image processing program called X2D . Click on the image to the left to find more information about this topic.


Multiresolution Design of Gabor Filter Banks for Texture Segmentation research summary. This novel method enables simultaneous design of both
  1. a set of tuned Gabor filters
  2. and an accompanying Bayesian classifier.
Click on the image to the left to find more information about this topic.

Lung segmentation and OpenGL rendering of segmented airway. Click on the image to the left to find more information about this topic.

An audio signal-processing program called Xvox . Click on the image to the left to find more information about this topic.

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Copyright 1995-2016, Thomas P. Weldon. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the author. Information on website is not affiliated or sponsored by any institution whatsoever, and is the solely the property of and/or its owners. 

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