Q Bounds for Arbitrary Small Antennas: A Circuit Approach

• Published in: IEEE transactions on antennas and propagation Vol. 60; no. 7; pp. 3120 - 3128
• Main Author: Thal, H. L.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-07-2012; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antenna theory; Antennas; Applied sciences; Circuits; Conductors (devices); coupled-mode analysis; electrically-small antennas; Envelopes; Exact sciences and technology; Gain; Integrated circuit modeling; Joining; Lower bounds; Materials; Mathematical models; Q factor; radar cross sections; Radiocommunications; Radiolocalization and radionavigation; Rayleigh scattering; Scattering; Shape; Telecommunications; Telecommunications and information theory; Wires; radar cross sections; Lower bound; Rayleigh scattering; Circuit parameter; Radar cross section; Antenna theory; Q factor; Circular polarization; Cylindrical antenna; electrically-small antennas; Coupled mode theory; Arbitrary shape body; Radar; coupled-mode analysis
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2012.2196920

Circuit models for the lowest-order modes radiating from within an arbitrarily-shaped envelope have been developed based on the exact circuits for spherical modes and the radar scattering from a conductor of the arbitrary shape. These circuits predict lower bounds on the Q of small antennas with any combination of coupling between modes. Circuit parameters are tabulated for a range of shapes, and the procedure for computing parameters for other shapes is explained. The bounds on a small circularly-polarized cylindrical antenna illustrate an application. Predictions for scattering by the arbitrary envelope filled with a high μ or ε material serve to validate the procedure.