Radio Frequency Fundamentals Flashcards
What is a radio frequency signal?
The transfer of data in wireless networks thanks to electromagnetic waves
How is a radio frequency signal produced?
A transmitter produces alternating current that is sent through cables and radiated out through an antenna as an electromagnetic wave
At what frequency does wireless communication usually occur at?
2.4GHz, 5GHz & 6GHz as microwave frequencies on the Electromagnetic Spectrum
What are the four properties of a wave?
Amplitude, Frequency, Wavelength & Phase
What is an amplitude?
Amplitude is the power, or singal strength of the Radio Frequency signal, mesaured in watts (W). Usually represented in a wavefrom as the maximum displacement of a wave
What is a frequency?
The number of times the signal makes one complete up and down cycle in 1 second. Measured in Hertz - 1Hz is one cycle per second.
What is a wavelength?
The distance that a single cycle actually travels, measured in meters or centimeters
What is a phase?
Phase is a relative term. It is the relationship between two waves with the same frequency
What is wave propagation?
Wave propagation is how an electromagnetic wave travels, with microwaves it doesn’t travel in a straight line, instead it travels in all kinds of directions, like a drop of water when it hits the water surface.
What may occur when a Radio Frequency is affected by obstacles or the medium itself?
Absorption, Reflection, Scattering, Refraction & Diffraction
What is Absorption?
Absorption is when a radiowave goes through an object, e.g. a door or a wall and the material of the object absorbs parts of the radio frequency, causing the speed of the radio frequency to slowdown.
What is Reflection?
Reflection is the opposite of absorption, when the RF hits a smooth surface, e.g. mirror/metal parts of the RF will change direction and reflect of the surface meanwhile the other part of the RF will slowly pass through the object.
What is Scattering?
Scattering occurs when an RF signal hits a small rough object, causing the RF to reflect into multiple smaller RF in all kinds of directions.
What is Refraction?
Refractions usually occurs in outdoor long distance senarios, when the RF may change direction or be affected due to the RF passing through a medium with different density, e.g. a cloud.
What is Diffraction?
Diffraction is the bending of an RF signal around the object, e.g. a river flowing around a bolder positioned in the middle of the river.
