A novel indirect method to determine the radiation impedance of a handheld antenna structure

Myles H. Capstick, Jari O. Jekkonen, Andrew (Andy) C. Marvin, Ian David Flintoft, Linda Dawson

Research output: Contribution to journalArticlepeer-review


A novel indirect measurement technique is developed in which the input impedance of an unknown antenna structure is determined by measuring the change in the measured input impedance of a second probe antenna, while the unknown antenna is loaded at its input by a set of known impedances. The feasibility of the approach is explored using method-of-moment boundary element simulations of the interaction between two dipole antennas in free space. Examples of the measurement of the helical antenna of a terrestrial trunked radio (TETRA) handheld radio and a small portable device with an electrically small antenna are presented. The significant advantage of the technique in the accurate measurement of electrically small antennas is confirmed.

Original languageEnglish
Pages (from-to)578-585
Number of pages8
JournalIEEE Transactions on Instrumentation and Measurement
Issue number3
Publication statusPublished - Mar 2009


  • Antenna measurements
  • antenna radiation impedance
  • impedance matching
  • indirect measurement
  • scattering parameters

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