Radio Frequency (RF) & Wireless Design

For those unacquainted with RF components, most of the parts are defined by deciBels (dB) for either Power (most common) or for Voltage in terms of gains or losses :

https://en.wikipedia.org/wiki/Decibel

A deci (1/10) of a Bel is used for Power since gains (or losses) are so large that they are in orders of magnitudes ( https://en.wikipedia.org/wiki/Orders_of_magnitude_(numbers) ) , and from the Power Equation P = V^2 * R, Voltages are in twice the orders of magnitudes of Electrical Power. This is because the log of a squared exponent is a 2x multiplier.

But where did all this start from one might wonder ? It started from fact that as waves move outward from a radiated source that the electro-magnetic wave has a diminished power directly proportional to the radial distance from the source. This is known as the Inverse Square Law (https://en.wikipedia.org/wiki/Inverse-square_law ) wherein the energy radiating from a source is inversely proportional to the radius squared, which is an exponent function.

So for RF energy radiating from a monopole or dipole omni-directional antenna ( https://en.wikipedia.org/wiki/Omnidirectional_antenna ) the RF energy will diminish closely related to the radial distance of the source (transmitter) to the load (receiver).

For a directional antenna (https://en.wikipedia.org/wiki/Directional_antenna ) the same philosophy still holds true, its just that the energy is focused in a particular direction and therefore will not suffer the losses as quickly.