Glossary







A
B C D E F G H I J K L M N O P Q R S T U V W X Y Z



A - E

Equivalent Isotropically Radiated Power (EIRP)

The amount of power that a theoretical isotropic antenna (which evenly distributes power in all directions) would emit to produce the peak power density observed in the direction of maximum antenna gain. EIRP can take into account the losses in transmission line and connectors and includes the gain of the antenna. The EIRP is often stated in terms of decibels over a reference power emitted by an isotropic radiator with an equivalent signal strength. The EIRP allows comparisons between different emitters regardless of type, size or form. From the EIRP, and with knowledge of a real antenna's gain, it is possible to calculate real power and field strength values.

F - J

Fresnel Zone

The area around the visual line-of-sight that radio waves spread out into after they leave the antenna. This area must be clear or else signal strength will weaken. (Pronounced “Fre-nel” with a silent ‘s’.)

Front-to-Back Ratio

Describes the ratio of power gain between the front and rear of a directional antenna. In other words, the ratio of received-signal strength when the antenna is rotated 180° backwards.

Gain

As a transmitting antenna, the figure describes how well the antenna converts input power into radio waves headed in a specified direction. As a receiving antenna, the figure describes how well the antenna converts radio waves arriving from a specified direction into electrical power. When no direction is specified, "gain" is understood to refer to the peak value of the gain. A plot of the gain as a function of direction is called the radiation pattern.


K - O

Near-field and Far-field

Generally refers to the distance an antenna is being measured from. These areas are generally determined by the size of the wave. The distance of one wavelength is generally referred to as “near-field” while two wavelengths is generally referred to as the transition zone. Anything beyond (into infinity) is referred to as the far-field.



P - T

Total Radiated Power (TRP)

A measurement of how the antenna and radio system will perform as a whole. It is a function of not just the antenna, but also the radio/transmitter and the connection between the radio and the antenna.


U - Z
 
 

Helpful Links


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site to this list, feel free to Contact Us.

Microwave News http://www.MicrowaveNews.com
Microwave News is a great resource for information on any new microwave R/F technology and industry news.

Microwave News http://www.Museum.tv
The Museum of Broadcast Communications has a rich history of the background of the entire microwave industry.