Magnetic Loop antennas
What is a magnetic loop antenna?
"Magnetic" because they take the magnetic component of a electromagnetic field, in contrast to the normal standard antennas (e.g. Dipole, Yagi, Vertical-antenna), which are in resonance only on the electric component.
Magnetic antennas can be created very compactly. Ideal in areas of limitated space or where mobility is required e.g. boats. No radials are required. The radiation is always the same, irrespective of the distance to the ground.
The antennas provide a small bandwidth on their resonance frequency. They have the advantage of less harmonics, and the effect of an additional preselector, focusing on just the required signal, ignoring non-required signals and intermodulation.