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What is the Near Field?

Huntsville Hamfest August 20-21, 2016
by

Hans Schantz

on 19 December 2016

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Transcript of What is the Near Field?

Many
Answers
See: Charles Capps, "Near Field or Far Field," EDN, August 16, 2001 pp. 95-102

Schantz, Hans G., “On the Superposition and Elastic Recoil of Electromagnetic Waves,” FERMAT, Vol. 4, No. 2, July-August 2014 [ART-2014-Vol4-Jul_Aug-002]. See also http://arxiv.org/abs/1407.1800
Gaussian Impulses
Average Energy Velocity for Various VSWR
Elemental Waves
Image Theory
Arbitrary Impulses
Schantz, Hans G., “On the Superposition and Elastic Recoil of Electromagnetic Waves,” FERMAT, Vol. 4, No. 2, July-August 2014 [ART-2014-Vol4-Jul_Aug-002]. See also http://arxiv.org/abs/1407.1800
Symmetric Impulses
Spacetime Diagrams
Electromagnetic Newton's Cradle
Don't Cross the Streams!
Energy velocity in terms of the normalized impedance…

Energy Velocity & Impedance
Normalized Impedance
Field Impedance
Extend application of impedance from circuits to fields,
Regard impedance as an attribute of the field as well as the medium
Sergei Schelkunoff
(1897-1992)
Oliver Heaviside
(1850-1925)
John Henry Poynting
(1852-1914)
Schelkunoff, S. A., “The Impedance Concept and Its Application to Problems of Reflection, Refraction, Shielding and Power Absorption,” The Bell System Technical Journal, Vol. 17, No. 1, 1938, p. 17-48.
Why use the more complicated Poynting-Heaviside Theory?
Skin Effect
AC Resistance
Electron Drift Velocity
Compare
These Models...
Field Impedance
(courtesy Mt. Holyoke College)
Heaviside, Oliver,
Electrical Papers,
Vol. 1, London: The Electrician Publishing Company, 1892, pp. 449-450. Originally published as “Electromagnetic Induction and Its Propagation,” in The Electrician, February 21, 1885.
Poynting, John Henry, “On the Transfer of Energy in the Electromagnetic Field,” Philosophical Transactions, Royal Society, London, Vol. 175 Part II, 1885, pp. 334-361.
Electromagnetic Energy Flow
Energy Velocity
(Plane Wave)
Heaviside, Oliver,
Electromagnetic Theory
, Vol. 1, The Electrician, London, 1893, pp. 78-80. In particular see Equation (15) on p. 79: http://bit.ly/1fmBZsw
What is the Near Field?
A New
Approach
Open and Short
Energy Velocity
Oliver Heaviside,
Electromagnetic Theory
, Vol. 1, (London: “The Electrician” Printing and Publishing Company, 1893), pp. 78-80. See: http://bit.ly/uCSzEw
Harry Bateman,
The Mathematical Analysis of Electrical and Optical Wave-Motion On the Basis of Maxwell’s Equations
, Cambridge University Press, 1915, p. 6. See: http://bit.ly/1ykUfeE
H. Schantz, “Electromagnetic Energy Around Hertzian Dipoles,” IEEE Antennas and Propagation Magazine, Vol. 43, April 2001, pp. 50-62. See: http://bit.ly/xGBOtb
Gerald Kaiser  “Electromagnetic inertia, reactive energy and energy flow velocity,” 2011 J. Phys. A: Math. Theor. 44 345206 http://arxiv.org/abs/1105.4834
Energy velocity

Oliver Heaviside (1850-1925)
Harry Bateman (1882-1946) in 1915,
v
< 1
Gerald Kaiser in 2011,
v
as a local time dependent characteristic of electromagnetic fields
Superposition & Analysis
What are we Ignoring?
What's
Really Going On?
Implications
Superposition: strong & weak
Superposition & analysis
What are we ignoring?
What's "really" going on?
What Else Are
We Ignoring?
What else are we ignoring?
Solar Flux (~1kW per
square meter)
Infrared Thermal Flux
Every Other Radio Signal
The implications?
Unlikely any of the transmitted energy ends up at the receiver
Average energy velocity less than c
Reality mostly near fields and standing waves, not far fields
Dirac's
Mistake?
Photon - Photon Interactions?
Photons & Standing Waves
Implications
For Physics
Energy flows in astrophysics
Energy associated with fields and waves from distant sources arises locally
The way the Lagrangian density varies in time and space gives rise to Maxwell's equations and all of electromagnetics through the principle of least action.
The energy balance determines how electromagnetics works.
What
is the
"Near Field?"

Hans G. Schantz, CTO
Q-Track Corporation
KC5VLD
August 20-21, 2016
h.schantz@q-track.com
Blog: www.aetherczar.com
Twitter: @aetherczar

Introduction
Overview: What is the Near Field?
Basics of EM and Energy Flow
How Near and Reactive Fields Work
Examples
Applications

Key Ideas
The Electric-Magnetic Balance
How Radio Waves "Bounce"
Application to Understanding Antennas and How Electromagnetics Works

Fields guide and perturb energy flow
Energy retains same order
Typical "drift" velocity < c
EM & QM
Energy Flow
EM Energy Flow Suggests Pilot Wave (deBroglie-Bohm) Quantum Mechanics
EM Waves Guide Energy
QM Waves Guide Particles
Bohmian Trajectories
"
Interference between two different photons never occurs.
"
-P.A.M. Dirac,
The Principles of Quantum Mechanics
, 4th ed. p. 9
Paul Dirac
(1902-1984)
How Electromagnetics Works
Summary
New interpretation -
not
new physics
Electric-Magnetic Balance Fundamental to Electromagnetics
Impedance
Normalized Lagrangian
Impedance Discontinuities in Media
or in Fields
Reflect Energy
Energy flow and field propagation follow different trajectories

Learn More
Details in
The Art and Science of Ultrawideband Antennas
http://bit.ly/UWBBook
E-Mail:
h.schantz@q-track.com
Twitter:
@aetherczar
Blog: http://www.aetherczar.com

Huntsville Hamfest
2016

Electromagnetic Basics
The Art and Science of UWB Antennas
, 2015, p. 289-292
The Art and Science of UWB Antennas
, 2015, pp. 282-283
Oliver Lodge
(1851-1940)
Lodge, Oliver, "Electrical Theory. Letters to Dr. Lodge,"
The Electrician
21, 1888, p. 829-831
1-D Transmission Line
Assign direction to impedance, and
Generalize the 1-D transmission line concept to higher dimensional problems in which some of the dimensions may be neglected.
One Dimensional Transmission Line
The Art and Science of UWB Antennas
, 2015, p. 289-292
Matched
(R = Z0)
Charging a Capacitor
High Source Z
(R = 10 Z0)
Low
Source Z
(R = 0.1 Z0)
Examples:
The Art and Science of UWB Antennas
, 2015, p. 289-292
Ivor Catt, M. F. Davidson, D. S. Walton, “Displacement Current, and How to Get Rid of It”,
Wirelesss World
, pp. 51-52 (Dec 1978).
The Art and Science of UWB Antennas
, 2015, Problem 4.6, p. 183
Ramo, Whinnery and Van Duzer,
Fields and Waves in Communications

Engineering
, 1994, Chapter 5
Dipole Impedance and Power
The Art and Science of UWB Antennas
, 2015, pp. 282-283
H. Meinke and F. Landstorfer,
Energy flow in wave fields,
NTG-Fachberichte Antennen 57, 42 (1977)
A&S pp. 322-329
Schantz, Hans, "Electromagnetic energy about Hertzian dipoles," IEEE Antennas and Propagation Magazine, April 2001, pp. 50–62.

Schelkunoff's
Dipole Impedance






Smith-Carter Chart
Power Factor
Radial Distance (wavelengths)
Time (periods)
Harmonic Dipole
Kirk T. McDonald, “Radiation in the Near Zone of a Center Fed Linear Antenna,“ June 21, 2004, updated August 7, 2012
see: http://www.academia.edu/7633567/Radiation_in_the_Near_Zone_of_a_Center-Fed_Linear_Antenna (calculation by Alan Boswell)
S.A. Schelkunoff and H.T. Friis,
Antennas: Theory and Practice

New York: Wiley, 1952, pp. 124-125
Time Average Energy Flow
Energy Flow Streamlines and Antenna Design
Landstorfer, F.M., and R.R. Sacher,
Optimisation of Wire Antennas
,
Letchworth, England: Research Studies Press, Ltd., 1985.
See in particular Chapter 4.
Standard Three-Quarter Wave Monopole
Optimized Three-Quarter Wave Monopole
Energy Flow Streamlines
and Antenna Design
H. Meinke and F. Landstorfer,
Energy flow in wave fields,
NTG-Fachberichte Antennen 57, 42 (1977)
Superposition: Strong or Weak?
No Energy Flow
No NET Energy Flow
Strong:
Many causes, but one
E
,
H
,
S
Weak:
Multiple
E
's,
H
's,
S
's
Why strong superposition?
Occam's Razor
Second Law of Thermodynamics
Reactive Energy Flow & Physics
QM &
Pilot Waves
"Electromagnetic energy flow lines as possible paths of photons"
M. Davidovic, A. S. Sanz, D. Arsenovic, M. Bozic, S. Miret-Artes
See arXiv:0805.3330v2
References:
"Electromagnetic energy flow lines as possible paths of photons," M. Davidovic, A. S. Sanz, D. Arsenovic, M. Bozic, S. Miret-Artes. See arXiv:0805.3330v2
T. Norsen, “The pilot-wave perspective on quantum scattering and tunneling,” American Journal of Physics, Vol. 81 No. 4, April 2013, pp. 258-266.
M. Davidovic, et al, “Electromagnetic energy flowlines as possible paths of photons,” Phys. Scr. T135, 14009 (2009) [arXiv:0805.3330].
S. Kocsis et al, “Observing the Average Trajectories of Single Photons in a Two-Slit Interferometer,” Science Vol. 332, 3 June, 2011, pp. 1170-1173.
K.Y. Bliokh, et al, “Photon trajectories, anomalous velocities and weak measurements: a classical interpretation,” New Journal of Physics, Vol. 15, (2013), pp. 1-17.
Electric vs
Magnetic Antennas
Two -20dBi ESAs
NEC 2D simulation of gain as a function of distance from PEC plane
"Electric" and "Magnetic" gain not equivalent
Combine for better multipath performance
Diffraction
References:
R.D. Prosser, “The Interpretation of Diffraction and Interference in Terms of Energy Flow,” International Journal of Theoretical Physics, Vol. 15, No. 3 (1976), pp. 169-180.
Vladimir Temari: http://www.ne.jp/asahi/tamari/vladimir/cancellationofdiffraction/image004.jpg
Diffraction
See:
M. Gondran and A. Gondran, “Energy flow lines and the spot of Poisson-Arago,” American Journal of Physics, Vol. 78, no. 6, pp. 598-602 [arXiv:0909.2302]
See: http://alexandre.gondran.free.fr/Fichiers/Energy_Flow_lines_Poisson_Arago.pdf
Lower Higher
Frequency
Near-Field Electromagnetic Ranging (NFER)
Range: 20-60m
Accuracy: 30cm-1m
Frequency ~1MHz
Capacity: ~80 tags
at 1Hz update
Q-Track Corporation
(www.q-track.com)
Applications
Indoor Location
Electric versus Magnetic Antennas
Understanding and Designing Antennas
Understanding Diffraction & Interference
Implications for Physics
Deterministic approach to QM
deBroglie & Born (1926-1927)
Bohm (1952)
Summary
of the Basics
Static:
E = 0 or H = 0
z
= 0 or infinity
or
v = 0
Radiation:
E /H = Zs


v = c
Reactive:
0 <
z
< 1 or
1 <
z
< infinity
or
v = S/u
Normalized
Lagrangian
Lagrangian:

Hamiltonian:

Normalized Lagrangian:
Reactive Fields
Note:
Assuming 1-D T-Line or

Do Photons Interfere?
Macroscopic EM waves exhibit a balance of E and H energy
Photons are quantized chunks of balanced electric and magnetic energy
Interference upsets the balance creating either virtual electric or virtual magnetic photons


Photons characterized by:
Relatively short mean free path
Relatively low drift velocity
Analogous to conduction
EM Energy Flow:
Normalized Impedance:

Normalized Lagrangian:
Continuum:





1-D Transmission Lines
EM Velocity:
Planetary
Motion
Fields
"
I can hardly imagine anyone, who knows the agreement between observation and calculation based on action at a distance, to hesitate an instant between this simple and precise action, on the one hand, and anything so vague and varying as lines of force on the other.
"
George Airy (1801-1891)
Correct
Models
Correspond to how reality really works
Integrate diverse facts into a simple conceptual model, and
Lay a foundation for further progress
Models & Reality
Questions?
Standing Waves:
Explain how the macroscopic characteristics of standing waves arise from "non-interacting" photons.
Superposition:
Strong or Weak?
Parsimony
Second Law of Thermodynamics
Full transcript