Electromagnetic Coupling Effects on the Cavity Measurement of Antenna Efficiency

Yeqin Huang, Ram M. Narayanan, Govind R. Kadambi

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


Electromagnetic coupling effects on the antenna in a conducting cavity are studied theoretically and experimentally. It is observed in experiments that at the resonant frequencies of the cavity, the input resistance of the antenna attains values two or three orders of magnitude higher than that at frequencies away from resonance. It is shown via theoretical analysis that the input resistance of the antenna measured at resonant frequencies of the cavity is not merely the loss resistance desired in computing the antenna efficiency, but is actually the sum of the loss resistance of the antenna and the coupling resistance between the antenna and cavity. This coupling effect is demonstrated quantitatively by numerical computations for dipole and monopole antennas. The computational results for the input resistance are in agreement with the measured data. A method is proposed to avoid the cavity-antenna antiresonance in the measurement.

Original languageEnglish (US)
Pages (from-to)3064-3071
Number of pages8
JournalIEEE Transactions on Antennas and Propagation
Issue number11
StatePublished - Nov 2003

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering


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