A low-frequency model for E-field and B-field coupling into a folded antenna with two gaps

Electric field coupling into electrically small monopoles/dipoles and magnetic field coupling into electrically small loop antennas has been investigated extensively due to their applicability to a wide range of applications. However, under certain conditions electrically small folded antenna structures exist in which both coupling mechanisms must be included simultaneously in order to perform an accurate system analysis. In this paper we present a low frequency model that includes both electric and magnetic field coupling simultaneously for a folded antenna with two gaps. Values for a circuit model are found using an electrostatic finite element code and a full wave frequency domain finite element code. The circuit model is then validated by a full wave finite difference time domain code. For the time domain analysis the antenna structure is excited by fields from a lightning pulse. The time domain simulation has excellent agreement with the circuit model that is presented.