On Representation of Electromagnetic Fields in Cavities in Terms of Natural Modes of Oscillation

In this paper we illustrate by a simple example that when we wish to express the admittance of a cavity excited through a hole in terms of natural frequencies of oscillations which can exist when the cavity is short‐circuited, it is important to remember that the short‐circuit must conform to the impressed field. When this is done, one need not fear that the ``obvious'' set of natural modes may be incomplete.