Polarization, Gain, and Q for Small Antennas

• Published in: IEEE transactions on antennas and propagation Vol. 59; no. 12; pp. 4844 - 4848
• Main Author: Thal, H. L.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-12-2011; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antenna theory; Antennas; Applied sciences; Coupled mode analysis; Dielectric materials; Dipole antennas; electrically-small antennas; Exact sciences and technology; Gain; Magnetic cores; Magnetic materials; Q factor; Radiocommunications; Telecommunications; Telecommunications and information theory; Performance evaluation; Antenna theory; Q factor; Magnetic material; Dielectric materials; Volume; electrically-small antennas; coupled-mode analysis; Coupled mode theory; TM mode; TE mode; Antenna
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2011.2165508

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.