Abstract: The invention describes a method and an apparatus for generating and receiving electromagnetic waves for test purposes and is applicable particularly for measurements, investigations and tests of electromagnetic compatibility. For testing the immunity, the test piece is acted upon with defined field parameters and, during the emission measurement, the electromagnetic radiation emitted by the test piece is measured. It is an important distinguishing feature of the invention that a cell, constructed as a TEM waveguide, is rotated about the test piece. The apparatus is characterized in that the lid and bottom of the pyramidal cell are constructed so as to be electrically conducting and in that two-dimensional septa, which consist of individual wires of equal length, are disposed in each case symmetrically at a small distance from the lid and the bottom.