Radio Frequency Faundamentals Flashcards
Wavelength
A fundamental characteristic of RF which describes the distance between two successive crests (or troughs) of a wave pattern.
Frequency
A fundamental characteristic of RF which describes the number of cycles an RF experiences in a certain time interval.
Amplitude
A fundamental characteristic of RF which describes the strength or power of a signal.
Phase
A fundamental characteristic of RF which describes the relationship between two or more signals, specifically, the positioning of the position of the peaks and troughs of the signals.
Wave Propagation
A term which describes the way in which RF signals travel away from an antenna.
Absorption
A behavior of RF where when a signal encounters a material, it can be “absorbed” by that material, meaning that the signal strength is either partially or fully diminished without a byproduct.
Reflection
A behavior of RF where when a signal encounters an object larger than a wave itself, depending on the material and surface the wave may bounce in another direction.
Scattering
A behavior of RF where when a signal hits a surface capable of reflection, but is “scattered” in that many smaller, less powerful signals are reflected in multiple directions.
Refraction
A behavior of RF where when a signal encounters a material of a varied density, a change in direction of the signal, or a bend in the path of the signal.
Diffraction
A behavior of RF where when a signal encounters an object, it bends around the object, taking the path of least resistance.
Attenuation
A term used to describe a loss in amplitude (or strength) due to the behaviors of RF signals.
Free Space Path Loss
A behavior of RF where as a signal travels, the signal will attenuate despite the lack of obstructions. This is not a linear function.
Multipath
An phenomenon where two or more paths of a signal arrive at a receiving antenna at the same time.
Upfade
A constructive multipath phenomenon where multiple signals arrive at the receiver either in phase or partially out of phase (less than 120 degrees) causing an increase in signal strength.
Downfade
A destructive multipath phenomenon where multiple signals arrive at the same time but are out of phase with the primary wave (greater than 120 degrees) causing a reduction in the signal strength.
