Mutual coupling in multi-antenna systems: Figures-of-merit and practical verification

The simple evaluation of mutual coupling effects is essential to the optimisation of antenna arrays for small mobile communications devices. We propose novel figures-of-merit in terms of the scattering matrix of the array that quantify the impact on diversity reception. The practical signification is proved by diversity measurements. Since the new formulas capture all information in a single number, they greatly simplify the broadband characterisation of compact arrays.