Generally, people are looking for small, wideband, efficient antennas. However, the limits of electrically short wire and rod antennas appear in low radiation resulting in difficulty couple significant power as the length to wavelength ratio decreases. The accepted way to calculate the radiation resistance or impedance of an antenna is to surround it with a hypothetical...
A small physical size is often required in many low power radio applications. Short antennas usually present a capacitive load with an antenna impedance less than fifty ohms. A network analyzer is usually used the determine impedance measurements and signal matching...
