## About

57

Publications

103,705

Reads

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3,819

Citations

Citations since 2017

Introduction

Hans G. Schantz currently works as Principal Scientist at Geeks and Nerds Corporation. Hans does research in Electromagnetism and Electrical Engineering. His current project is 'How Electromagnetics Works'.

Additional affiliations

January 2019 - present

**Geeks and Nerds Corporation**

Position

- Principal Investigator

October 2002 - January 2019

**Q-Track Corporation**

Position

- Chief Technical Officer

December 1999 - April 2002

**Time Domain Corporation, Huntsville, United States**

Position

- Engineer

## Publications

Publications (57)

This paper considers the behavior of electromagnetic energy around
Hertzian dipoles. The method of “causal surfaces” (surfaces
through which there is no net flow of electromagnetic energy) is used to
partition and track the energy. A variety of examples, involving both
transient and harmonic time dependence, are presented, to illustrate the
way in...

Conventional definitions of ‘near fields’ set bounds that describe where near fields may be found. These definitions tell us nothing about what near fields are, why they exist or how they work. In 1893, Heaviside derived the electromagnetic energy velocity for plane waves. Subsequent work demonstrated that although energy moves in synchronicity wit...

Geometric and physical optics provide intuition for understanding electromagnetic propagation. Other complimentary intuitions are possible from energy flow. Extending upon the 2002 work of Wünscher, Hauptmann, and Herrmann, this paper tests their counter-intuitive rules of energy flow, presenting Numerical Electromagnetic Code (NEC) derived results...

Ideal electromagnetic waves include synchronized electric and magnetic waves conveying equal amounts of electric and magnetic energy at the speed of light. The ratio of the electric to magnetic field is the free-space impedance, 376.7 ohm. Close to the source, however, the electric and magnetic components of the wave are no longer synchronous. When...

Ultra Low Frequencies (ULF: 300Hz-3kHz) and Very Low Frequencies (VLF: 3 kHz-30 kHz) are of great value for applications as diverse as Assured Precision Navigation and Timing (APNT), and robust low-data rate communications underwater, underground, and in urban environments. A ten harmonic (N = 10) Narrow Band Impulse Radio (NBIR) offers about a 20d...

This paper reviews a variety of techniques for Very Low Frequency (VLF) wireless practice-radio frequency (RF) systems that operate at frequencies on the order of 3 kHz-30 kHz or less. Traditional far-field antenna properties, like gain and antenna factors, may be applied to these VLF radiating system. We may measure the properties of VLF antennas...

A wide variety of models are available to those who work in applied electromagnetics. We may study electromagnetics in the frequency domain or time domain. We can look at phenomena from the perspective of waves or energy flows. We might employ fields or potentials in our calculations. We may characterize antennas using either gain or aperture. In e...

Mutually orthogonal three-axis electrically-small magnetic antenna arrays are of great interest for field probes, direction finding, and location systems. Orthogonality does not guarantee minimum coupling between two or more antennas, however. A poorly designed antenna array will exhibit mutual coupling even between orthogonal elements, confounding...

This comprehensive treatment of ultrawideband (UWB) antennas and time-domain microwave engineering serves as an invaluable practical reference for anyone involved in antenna and RF design work. This authoritative volume enables readers to select the proper UWB antennas for their applications, design and analyze UWB antennas, and integrate these ant...

Gain measurements of very electrically small antennas (VESAs) present special challenges. These antennas radiate with poor efficiency, and great care is needed to make a suitable gain measurement using radiative techniques. This paper presents a novel gain measurement technique based upon the observation that the gain of well-matched VESAs is propo...

This paper presents, analyzes, and explains the propagation of energy in a variety of standing waves. Schelkunoff noted the duality of the impedance concept. In one sense, impedance defines the ratio of electric to magnetic field. In another sense, impedance describes the properties of a transmission line or medium that give rise to the same ratio....

A wireless channel multiplexing method which utilizes both electric and magnetic field components of an electromagnetic wave as separate information carriers in the near-field region is presented. It is shown that multiplexing gain can be obtained in free space in the absence of scattering as well as indoor environments. Measured indoor channels at...

Superposition demands that a linear combination of solutions to an
electromagnetic problem also be a solution. This paper analyzes some very
simple problems: the constructive and destructive interferences of short
impulse voltage and current waves along an ideal free-space transmission line.
When voltage waves constructively interfere, the superpos...

A system and method for determining a position of a locus comprising a locator device for disposition at the locus; the locator device configured for receiving an electromagnetic signal from a beacon device, the locator device receiving at a distance from the beacon device within near field range of the electromagnetic signal; the locator device co...

A wireless channel multiplexing method which makes use of the electric and magnetic field components of an electromagnetic wave as separate information carriers is presented. It is based on the observation that the rates of attenuation for electric and magnetic fields with respect to distance are different for electric and magnetic sources in the n...

We review previous work on modifying the far-field transmission formula to describe near-field links between electrically-small antennas. Then, we derive a simple and useful formula for the antenna gain (G) of a small loop antenna as a function of size (R), wave number (k) and loaded quality factor (QL), specifically: G = C QL (kR)^3 where C is a c...

Horns are an important class of UWB antenna. This paper presents a compact planar horn design well-suited to serve as a gain reference or UWB measurement instrument. The design was made both compact and well-matched by introducing a right angle turn in a tapered balun feed structure. This paper describes some of the design challenges in translating...

This paper provides a historical overview of ultrawideband (UWB) antennas. Early radio was narrowband in conception, but UWB in practice due to various technical limitations. Oliver Lodge pioneered UWB antenna engineering in the nineteenth century with his invention of both the biconical and bowtie antennas, and J.C. Bose demonstrated the first hor...

This paper presents a variety of directive, electrically-small ultra-wideband (UWB) antenna designs. Employing a multipole-synthesis design methodology yields stable patterns with directivity of +4.7dBi or more across multiple decade bandwidths. The antenna may be thought of as an electrically-short, resistively-terminated transmission line. Open f...

This paper illustrates the divergence of phase, signal, and energy velocities in the near field by employing space-time diagrams of the evolution of near-fields. In addition this paper describes near-field link and impedance relations a near-field phase diagram for electrically small quadrature transmitters. Near-field physics enables near-field el...

This paper will provide a brief survey of the origins of RF-based location technology through the beginning of the Second World War. Direction finding (DF) was invented by John Stone Stone in 1902 and improved upon by Lee de Forest, Ettore Bellini and Alessandro Tosi. Both radar and amplitude ranging date to 1904, although these concepts were in ad...

We provide results and error analysis for over four hundred individual measurements of a Near-Field Electromagnetic Ranging (NFER®) Real-Time Location System (RTLS). The system operated over ranges from 1.41m to 23.4m and the bulk of the points were taken “through wall” in a non-line-of-sight configuration. We break the error down into orthogonal r...

There exist a wide variety of commercial RF devices ranging across the spectrum from the Low Frequency band (e.g. 125 kHz) to mm-wave (e.g. 60 GHz). " High " frequencies (which in this context mean VHF, UHF, microwaves and beyond) are well suited for data communications at high bandwidths. Where the emphasis is on signals penetration and propagatio...

This paper presents a continuous pulse ultra-wideband (or C-UWB) UWB data link exploiting the spectral properties of "truncated sine waves." A truncated sine wave is a sine wave of finite duration - typically a low integer multiple number of periods. This paper further explores truncated sine wave pulses and presents several straightforward RF arch...

A fundamental limit on an antenna's gain is derived and compared to measurements taken on a number of different antennas. First, a propagation formula applicable in both the near and far fields is developed, and that result is used to demonstrate that the gain of an antenna is limited by its electrical size.

"Over the last few years much has been published about the principles and applications of electromagnetic waves with large relative bandwidth, or nonsinusoidal waves for short.The next step is the development of the technology for the implementation of these applications. It is generally agreed that the antennas pose the most difficult technologica...

Near-field electromagnetic ranging (NFER) technology is emerging as a preferred real-time locating system (RTLS) solution for operation in complicated indoor propagation environments [H. Schantz and R. DePierre, 2005]. Operating at low frequencies, typically within the AM broadcast band (530-1710kHz), NFER systems exploit the near-field behavior of...

Long considered a technical backwater, low-power, near-field systems are emerging as the preferred solution for a variety of useful applications. These applications include short-range communication, radio frequency identification (RFID), and real-time locating systems (RTLS). This paper explores the ultra-low-power and thus low-probability of inte...

A comprehensive statistical model is described for ultrawideband (UWB) propagation channels that is valid for a frequency range from 3-10 GHz. It is based on measurements and simulations in the following environments: residential indoor, office indoor, builtup outdoor, industrial indoor, farm environments, and body area networks. The model is indep...

This paper explains and surveys the emerging RF discipline of near-field technology. First, this paper defines what is meant by the "near field." Then, this paper presents a brief history of near-field technology from Faraday to the present day. In particular, this paper focuses on recent advances in near-field technology for applications like Near...

This paper introduces the concept of a "nanoantenna:" a device that radiates UWB impulses from the discharge of a conducting enclosure antenna. By trapping exterior electrostatic energy, a nanoantenna has the potential to radiate energy more efficiently than generally believed possible, enabling efficient millimeter scale 3.1-10.6 GHz UWB devices.

This paper presents experimental results for a variety of planar bulbous UWB antennas including elliptical and ovoid shapes. This paper further considers the shapes and assesses which shapes yield the best combination of size and performance.

The paper presents a theoretical analysis of the near field channel in free space. The theoretical model is then validated by comparison to data measured in an open field. The results are important for low frequency RF systems, such as those operating at short range in the AM broadcast band (525-1715 kHz). Finally, the paper establishes a novel fun...

The paper presents a theoretical analysis of the energy flow around an ideal harmonic dipole and establishes a novel limit for antenna efficiency versus antenna size.

This paper presents a theoretical analysis of near field phase behavior in free space. Then this paper validates the theoretical model by numerical modeling and comparison to experimental data. Near field phase behavior is the basis of a novel RF tracking technology, with a demonstrated accuracy of 30 cm at ranges up to 70 m.

This paper describes a comprehensive statistical model for UWB propagation channels that is valid for a frequency range from 3-10 GHz. It is based on measurements and simulations in the following environments: residential indoor, office indoor, built-up outdoor, industrial indoor, farm environments, and body area networks. The model is independent...

This paper introduces the concept of an electrically small two element antenna array that can provide unambiguous angle of arrival information for broadband or ultra-wideband (UWB) signals. Applications include interference mitigation, location awareness, and in a "spatial RAKE" receiver system.

This paper discusses the phenomenon of dispersion in UWB antennas and presents a simple model to evaluate the time domain radiated fields from an antenna structure. This model allows a quick assessment of dispersion.

This paper provides an historical overview of ultra-wideband antennas presenting key advances at the root of modern designs.

This is a discussion document for the IEEE document of the IEEE 802.15.4a channel modeling subgroup. It provides models for the following frequency ranges and environments: for UWB channels dovering the frequency range from 2 to 10 GHz, it covers indoor residential, indoor office, industrial, outdoor, and open outdoor environments (usually with a d...

This paper presents an introduction to ultra-wideband (UWB) antennas, including a summary of key UWB antenna concepts, as well as system and network considerations, and fundamental limits for UWB antennas.

This paper describes a method for creating frequency notches in an otherwise ultra-wideband (UWB) antenna element. By deliberately introducing a narrow band resonant structure, an antenna may be made insensitive to particular frequencies. This technique is useful for creating UWB antennas with narrow frequency notches, or for creating multi-band an...

This paper describes the "bottom fed" planar elliptical dipoles. These antennas are electrically small ultra-wideband (UWB) dipoles with bandwidths on the order of 3:1 or better. Return loss is typically -14 dB, and boresight gain is nominally 3 Bi. Bottom fed planar elliptical dipole antennas are well suited for commercial applications.

Many commercial applications call for UWB antennas that are less prone to near-field coupling. Magnetic antennas are well suited for these applications, because the relatively large magnetic fields tend not to couple as strongly with near-by objects. The purpose of this article is to provide a brief overview of some UWB magnetic antennas. In partic...

This paper describes a version of the "Wheeler (1959) Cap method" modified for evaluating the efficiency of ultrawideband (UWB) antennas and discusses the application of this method to a Time Domain Corporation BroadSpec™ Model 102 antenna. This antenna exhibits a radiation efficiency better than 90% from 1.5 GHz to above 6.0 GHz.

This note introduces a new class of planar ultra-wideband (UWB) dipoles that use elliptical elements. These antennas offer good dipole performance over nearly two octaves in frequency. Unlike more traditional broadband dipole elements that must be around a quarter-wavelength to radiate efficiently, planar elliptical UWB dipoles still exhibit a -10...

This paper has explored the difference between conventional CW array design and short pulse UWB array design. In particular,
the grating lobe suppression of a short pulse array was emphasized. Although conventional CW array theory can adequately predict
the main lobe pattern of a broadside linear UWB-SP array, it does not adequately model performan...

As Oliver Heaviside observed, “However mysterious energy (and its flux) may be in some of its theoretical aspects, there must
be something in it, because it is convertible into dollars, the ultimate official measure of value.”22 The ability to track electromagnetic energy is helpful in designing antennas with low reactive field energy. Such antenna...

The usual narrowband or resonant techniques, for measuring antenna
efficiency are ill-suited for use with ultra-wideband (UWB) or aresonant
antennas. This paper develops an extension of the classic "Wheeler
(1959) cap" technique that can be applied to UWB antennas. The theory of
UWB antenna efficiency is developed, and the techniques of the paper a...

A ultra-wideband (UWB) magnetic slot antenna allows for
polarization diverse UWB systems when used in conjunction with a UWB
dipole, and has the added advantage of reduced cable currents, thus
eliminating the need for a balun. These advantages were the motivation
behind the development of the complimentary tapered bow tie (COTAB) UWB
magnetic slot...

When a typical narrowband antenna is excited by an ultra-wideband
(UWB) impulse, the antenna rings at its resonant frequency, stretching
out the waveform in time. A resonant antenna, like the bow tie, discone,
or bicone have been available for years. A bow tie has a relatively high
input impedance, and requires a matching balun to make it useable w...

The MCAT exam (taken by students seeking entry to medical school) is drastically different from the standard university course test. The MCAT emphasizes reading and analytic skills far more than quantitative analysis, even on the sections that test physics. I describe these differences, and outline an introductory physics curriculum focused to the...

The traditional methods of visualizing electromagnetic radiation focus on locating ''kinks'' in the electric field lines. This method can be used only for very simple situations, such as an accelerating point charge. In this talk, I will present an alternate method that focuses on the magnetic field lines. I will show how this method can be used to...

In a typical dipole decay, the induction magnetic field and the radiation magnetic field are in opposing directions. The former is dominant close to the decay, and the latter is dominant far away. Thus, there exists a surface on which these two components cancel each other, so that the magnetic field reverses direction. Because the magnetic field c...

The scattering of an arbitrary transient plane wave by a spherical inclusion in a Biot medium is modeled, by applying the single frequency, steady?state solution of Zimmerman and Stern [ 527?536 (1993)] to the discrete Fourier components of the transient signal, and assuming linear supersposition. The solution of Zimmerman and Stern is an analytica...

Thesis (Ph. D.)--University of Texas at Austin, 1995. Vita. Includes bibliographical references (leaves 81-85).

The range of validity is displayed for results predicted by the Mori-Tanaka micro-mechanics model. The general model type is that of spherical inclusions in a continuous matrix phase, for a polydisperse (size) suspension. The elastic shear modulus is the quantity of evaluation, using the generalized self-consistent method to give a rigorous result.

## Questions

Question (1)

The energy (E) in an electromagnetic wave is quantized in amounts proportional to the frequency (f) where the constant of proportionality is Planck's Constant (h): E = h f. This suggests that electrostatic and magnetostatic energy (where f = 0) are effectively continua because the quanta become infinitesimally small at zero frequency. Does anyone have a contrary interpretation or any further insights on this question?