Inductive twin-strip gratings in incident TE waves

The inductive sides of square loops, or the inductive end caps of the Jerusalem cross, are regarded as segments of a regular strip grating, in order to devise equivalent-circuit models of frequency surfaces. This approximation involves errors, depending on frequency, angle of incidence and the choice of the grating. These are investigated here by analysing the case of inductive twin-strip gratings in TE incidence, and comparing them with regular gratings, giving specific examples.