Date of Award
Spring 1963
Document Type
Thesis - Restricted
Degree Name
Master of Science (MS)
First Advisor
Ishii, Thomas K.
Second Advisor
Horgan, J. D.
Abstract
The subject of this thesis is waveguide branches. A straight section of rectangular wave guide can be intersected by a second section of waveguide in either its wide or narrow side. These two types of intersections are called E- and H-plane branches, respectively. These intersections can be made at any angle so that a complete description of the configuration includes the type of branch and its angle. Physically, these waveguide configurations have three inputs --two are collinear and one is the branch arm. This thesis presents predictions and measurements of the phase shift of electromagnetic waves propagating across the collinear arms of microwave wave guide E- and H-plane branches of arbitrary angle. All considerations are based upon a collinear arm being the input port and the other arms being terminated with reflectionless terminations. The phase shift across the E-plane branches was found to be approximately zero degrees. This can be predicted if the waveguide wavelength is considered a function of waveguide width, The waveguide width across any E-branch is identical to the width across a section of empty waveguide so no phase shift difference should exist between the two configurations. The phase shift across the H-plane branches was found to be a function of frequency with the minimum phase shift of about 30 degrees for the 90 degree branch configuration and about 120 degrees for the 22.5 degree branch configuration. These phase shifts were found to be a function of frequency, The phase shift measured across the H-plane branches of arbitrary angle was predicted considering the waveguide wavelength a function of the waveguide width, This function also predicted a decrease in phase shift with increasing frequency which agreed with the experimental results. Measurements of the attenuation across the collinear arms are also presented. At all branch angles, both E- and H-plane, between 45 and 60 percent of the power was transmitted across the collinear arms. Most of the remaining power was coupled from the collinear arm to the branch arm. Less than 10 percent of the power was reflected from the collinear arm inputs of the configurations tested. Microwave waveguide bridge accuracy, techniques, and associated problems are considered in detail. The accuracy of the bridge measurements were found to be limited by the accuracy of the precision phase shifter and attenuators of the bridge. The error in bridge phase shift balance due to inserting components of different lengths in each side of the bridge was evaluated and experimentally verified. These errors were found to be extremely small and negligible for reasonable differences in lengths of components inserted in the bridge arms.
Recommended Citation
Schumacher, Damian E., "Behavior of Electromagnetic Waves At a Waveguide Branch" (1963). Master's Theses (1922-2009) Access restricted to Marquette Campus. 4174.
https://epublications.marquette.edu/theses/4174