Analysis of an Open-Ended Waveguide as a Probe for Near Field Antenna Measurements by Using TLM Method

Yoshiyuki FUJINO
Cheuk-yu Edward TONG

IEICE TRANSACTIONS on Communications   Vol.E77-B    No.8    pp.1048-1055
Publication Date: 1994/08/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Antennas and Propagation
TLM method,  time domain analysis,  near field antenna measurements,  open-ended rectangular waveguide,  

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To increase the accuracy of a near field antenna measurement system, it is necessary to know radiation characteristics of a probe to detect near field data. Open ended waveguide used as a near field probe in our system was analyzed using Transmission Line Matrix (TLM) method which is a time domain electromagnetic solver. Validity of this analysis has been confirmed by comparison with experimental data and existing theoretical approximation. Frequency dependence of a complex reflection coefficient at the waveguide aperture has been derived and is shown to agree with measured values. The radiation pattern of the open ended waveguide with mounting structure is also calculated. Ripples on both the amplitude and phase patterns are correctly predicted by our simulation. This method can be applied to accurately model the effect of probe antennas to enhance the accuracy of near field antenna range.