MagneticLoopA loop antenna is actually sensitive to the magnetic field and not the electric field (it is also called a magnetic loop).
They form another antenna types, which features simplicity, low cost and versatility. You l'll find loop in various shapes; square, circle, triangular, etc.
Widly used up to 3 GHz.. electrically small C<0.1 lambda , electrically large C~lambda. Broadcast AM (tube or transistor) radios are usually equipped with ferrite loop antennas. Such Magnetic Loop antenna are widley used in WIFI antennas too.

magnetic field

A bit of theory.
Know how to solve Maxwell equations ,Gauss' law for electricity and magnetism? Ready-made and easy to use calculation programs.
Many way's to build your Magnetic Loop. There is a lot of information available on the net, concerning Magnetic Loop Antennas.
Good books about Magnetic Loops are the ARRL antenna book Chapter 5 tabel 3.
And the  Rothammel  Antennabook.

Described a lot of theory and design, on the Magnetic fields, Magnetic Loop and shielded loop antennas, formula's etc. Also the importance of direction finding antenna's (handy for searching QRM / man make noise near your QTH).

The best way to success is: Make first, several small Magnetic Loops for example for 2 meter or 70 cm. Using WICU pipe ( 12/15/22mm or thicker) or 6mm thick copper oil pipe, This is made from a soft red copper material and easy to bend, and to process.
Advantages: - Easy to build - Good RX (High Q) - Reduction of man make noise - Small size, handy in small gardens .
Disadvantages: Small bandwidth - Dangerous high voltage on the capacitor ( 100 watt = 3 Kv ) - Strong magnetic field, keep distance by high power 100 watt or more.