Date of Award

5-2009

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Electrical Engineering

Advisor

Pearson, Wilson

Committee Member

Hubing , Todd

Committee Member

Martin , Anthony

Abstract

This thesis discusses spherical near-field measurements implemented by a circular waveguide probe which has much shorter length and wider operating range than those proposed similar circular probes. A brief introduction of spherical near-field measurement techniques is provided first. We also introduce the well-known conclusion that utilizing first-order probes simplifies the measurements and associated near-field to far-field transformation. Accordingly, a relatively short circular waveguide probe antenna is designed and fabricated. Detailed fields of this probe are analyzed to demonstrate that it is still a first-order probe even though the length is short. Furthermore, it radiates only first-order fields over a wide frequency range, indicating it is applicable as a near-field measurement probe in this range. This wide operating range is because of the use of symmetry to control unwanted modes. We also exploit the concept that a first-order probe can be realized with two first-order modes: TE11 and TM11. Probe calibration results also evidence these findings. This circular waveguide probe is then utilized to examine a base station antenna in its near-field range. The transformed far-field patterns validate the practicability of our probe.

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