Illustrations of physical bounds on directive antennas

Applications of physical bounds for electromagnetic radiators can be used to derive a priori estimates for antenna parameters in terms of the directivity-bandwidth product. These estimates relate the static electric and magnetic polarizability of the radiating structure to its dynamic properties. The results have previously been illustrated for dipole radiators with good agreement. Here, the bounds are illustrated for some antennas with complex radiation patterns, i.e., directivity greater than 3/2 and narrow beams. The a priori estimates show good agreement with the realized antenna parameters.