static electricity
- The separation of charges
- Opposite charges attract and like charges repel each other
Current Electricity
The movement of electrons through a conductive material in a uniform direction
Magnetism
- force exerted by magnet when they attract or repel each other.
- Caused by the motion of electric charges
Charles-Augustin de Coulomb
- 18th century
- attractive and repulsive nature of electrical charges and magnets
- inverse square law, the force is inversely proportional to the square of the distance between the charges
André-Marie Ampère
- 19th century physicist
- relationship b/w electricity and magnetism
- magnetic needle affected by current in a wire
Michael Faraday
- 1821
- link b/w electricity and magnetism
- magnet and electricity in wire
- light can be affected by electrical currents
James Clerk Maxwell
- 1862
- speed of electromagnetic field = speed of light
- light is an electromagnetic disturbance
Electromagnetic (EM) Radiation
the flow of energy (photons) at the speed of light through free space or through a material medium in the form of electric and magnetic fields that make up electromagnetic waves
photon
The movement produces an oscillating (orthogonal) e-field and b-field, which travel perpendicular to each other in a bundle energy
Young’s Double Slit Experiment:
Proved Light exhibits properties of waves
Electromagnetic Wave
a wave that is composed of oscillating magnetic and electric fields.
sine wave
continuous, uniform wave with a constant frequency, amplitude, and phase.
Characteristics of a Wave
Amplitude
Wavelength
Frequency
Phase
Polarization
Amplitude
- A
- height of wave
power
wavelength
- λ
- distance from peak to peak, trough to trough
Frequency
- v
- number of cycles per second
- hertz
- 1000hz = 1KHz…what is 1 GHz? 1,000,000,000 Hz = 1M KHz = 1000 MHz = 1 GHz
1000hz = 1KHz…what is 1 GHz?
1,000,000,000 Hz = 1M KHz = 1000 MHz = 1 GHz
Wavelength and Frequency Relationship
the shorter the wavelength, greater the frequency (inversely proportional)
Energy and Frequency Relationship:
The greater the frequency the higher the energy (directly proportional)
Phase
- ⏀
- offset
Polarization
- orientation of a wave, typically from the e-field perspective
- linear or circular
Atmospheric layers
o Low frequency – effected by scintillation
o High frequency – effected by atmospheric effects (water droplets and moisture
o Middle – X band (IEEE), best place/balance
