EVALUATION OF MUTUAL COUPLING BETWEEN SLOTS FROM DIPOLE EXPRESSIONS

Two closed form approximations are given for mutual cou- pling between arbitrarily oriented slots with cosinusoidal distribution, using the known results for dipoles along with a new correction fac- tor to account for the piecewise sinusoidal dipole current. Using these approximations, a scheme has been developed for calculating mutual coupling between practically used slots of arbitrary orientation and useful results are obtained from simple closed form expressions for slot separation of 1:2 £ slot length or more depending upon the approxi- mation chosen and the length of the slot. These approximations are found to be more accurate than those available in the literature, with a maximum error of less than 1.6% for slots shorter than 0.5 wavelength and separated by 0:85 £ wavelength or more. Simple yet accurate expressions for mutual coupling, like the point dipole approximation developed here, result in e-cient evaluation of mutual coupling for the design of large arrays of slots or for Electromagnetic Compatibility analysis.