Title :
Physical limitations of antenna
Author_Institution :
Research In Motion, Waterloo, Ont., Canada
Abstract :
A discussion of minimum possible antenna quality factor (Q) is first presented . Based on the spherical wave function theory, the maximum possible ratios of gain to Q for both directional antenna and omnidirectional antenna are examined and new upper limits for both cases have been obtained. Universally applicable numerical results and some related discussions are also included.
Keywords :
Q-factor; directive antennas; modal analysis; antenna physical limitations; antenna quality factor; directional antenna; maximum gain to Q ratio; omnidirectional antenna; radiated power; small antennas; spherical mode theory; spherical wave function; time averaged stored energy; upper limits; Antenna theory; Bandwidth; Directional antennas; Directive antennas; Electromagnetic fields; Helium; Polarization; Polynomials; Q factor; Wave functions;
Journal_Title :
Antennas and Propagation, IEEE Transactions on
DOI :
10.1109/TAP.2003.814754
