Abstract:
At UHF band i.e. 300-3000MHz overall size of the antenna is very large. In order to realize multiple degrees of freedom from multi-element antenna array at this frequency, it is optimal to place the elements d>λ/2 for minimal coupling which makes the overall size of the antenna array very large. Whereas compact arrays result in increased mutual coupling which severally affects the efficiency of the available degrees of freedom and for some cases it result in loss of degrees of freedom. This would also result in loss of diversity gain normally stated for multi-element antenna array as due to coupling the beam patterns are correlated and also the impedance mismatching causes the power losses.
