Introduction and History Electromagnetic Wave Propagation
Velocity
![[Under Construction]](images/undercon.gif){kind=small}
The velocity of electromagnetic wave propagation
is described by the speed of light in a material. The speed of light in a material
is always slower than the speed of light in vacuum (or free space). The velocity is
controlled by the ability of the material to store energy by pushing back against an
externally applied force. In electromagnetism, this is described by dielectric permittivity and magnetic
permeability polarization properties. When charged particles travel faster than
the speed of light in a material, they generate a wake like a sonic boom, emitting Cherenkov radiation (the blue glow around water cooled
nuclear reactors).
The square of the velocity of propagation is equal to the
reciprocal of the product of the complex permittivity times the complex permeability.
In most low loss, nonmagnetic materials, this reduces to the velocity of
propagation in the material is equal to the speed of light in vacuum, c, divided by the
square root of the relative dielectric permittivity.
From the propagation constant and the wavenumber,
g = propagation constant
k = wavenumber
w
= radian frequency = 2p fm
= magnetic permeabilitys
= electrical conductivitye
= dielectric permittivitye
r= permittivity relative to free spacea
= attenuation constantb
= phase constantc = speed of light in vacuum
Wavelength Attenuation Dispersion
Rocks, Soils and Fluids: Electrical Properties Magnetic Properties
Environmental Influences Heterogeneity, Anisotropy and Scale Radar Equation
Scattering Polarization Fresnel Reflection Snell Angle Stokes-Mueller Matrices Poincare Sphere
Antennas Coupling Near / Far Fields Waveguides Multipathing Resonance
Survey Design Contrast Geometry Resolution Depth of Investigation Orientation
Data Acquisition Data Processing Modeling Interpretation Uncertainty
Applications: Noninvasive Surface Borehole Airborne Satellite