Electromagnetic waves are made up of Electric Fields (often called the E-field) and magnetic fields. What is an E-field?
Technically, the E-field at a point in space is a measure of how strong the fo ...
EIS is the Effective Isotropic Sensitivity. In antenna measurements, the measured sensitivity in a single direction (that is, for a fixed and ) is known as the EIS.
Typically, for an antenna system ...
S-parameters describe the input-output relationship between ports (or terminals) in an electrical system. For instance, if we have 2 ports (intelligently called Port 1 and Port 2), then S12 represents ...
EIRP is Effective Isotropic Radiated Power, also called the Equivalent Isotropic Radiated Power. In antenna measurements, the measured radiated power in a single direction (that is, for a fixed and ) ...
An antenna is said to be resonant if its input impedance is entirely real, i.e. Zin = R + j*0.
In this case the voltage and current are in phase at the antenna's terminals. This property makes the i ...
The E-plane is any plane that contains the E-field and the direction of maximum radiation from the antenna. As an example, consider a short dipole, the electric fields are given by:
This states t ...
Reciprocity is one of the most useful (and fortunate) property of antennas. Reciprocity states that the receive and transmit properties of an antenna are identical. Hence, antennas do not have distinc ...
We know that the permittivity of a material relates to (1) the speed of propagation of an electromagnetic wave thorugh a material, and (2) the energy stored by an Electric Field within a material.
...
The Q of an antenna is a measure of the bandwidth of an antenna relative to the center frequency of the bandwidth. If the antenna operates over a band between f1 and f2 with center frequency fc=(f1+f2 ...
Desense is the degradation in sensitivity due to noise sources, typically which are generated by the same device the radio is in. An example will make this clear.
Suppose we are looking at a certa ...
Dielectric Constant - Permittivity
In Electromagnetics, permittivity is one of the fundamental material parameters, which affects the propagation of Electric Fields. Permittivity is typically denot ...
Permittivity is a property of a medium or a region of space. On this page, I'm going to give its meaning as it relates to antenna theory, with only a small explanation on the physics behind it. The pe ...
The decibel system (and the properties of logarithms) makes the mathematics involved in some equations much simpler. For instance, recall the Friis Transmission Formula:
(*)
To convert ...
Many parameters related to antennas are measured in decibels; for instance, gain is often specified in decibels, written as 10 dB. Or maybe the minimum received power for an antenna system to work is ...
Permeability is a property of a medium or a region of space. On this page, I'm going to give its meaning as it relates to antenna theory, with only a small explanation on the physics behind it. The pe ...
