Polarization, Gain, and Q for Small Antennas

The six lowest-order modes that can be excited by a small antenna can be combined to produce patterns with a variety of polarization, gain, and Q characteristics. Tables and equations are presented to define bounds on the performance of these antennas for spherical and hemispherical volumes, including the effects of both external and internal energy. The impact of dielectric and magnetic material on the TM and TE modes is detailed, and it is shown that a thin shell of high-μ material allows the Q of both modes to approach the Chu bound.