Theory of side windows in wave guides
The effect of a window in the side wall of a wave guide is calculated. The window is assumed small so that it can be described by the lumped constants (polarizabilities) defined in Report 43-22. A side window is in general neither equivalent to a simple shunt nor to a series element in a transmission line. This is different only in some simple cases, for example, a window in the narrow side of a rectangular guide acts as a simple shunt reactance. The excitation of one wave guide (secondary) by another (primary) through a window in a common side wall is calculated. Waves will go out from the window in both directions of the secondary guide but in general their amplitudes will be different. In particular, only a wave going backwards (i.e., opposite to the wave in the primary guide will be excited in the secondary guide if the two guides are ordinary rectangular guides of width a = lambda/sub 0//..sqrt..2 (lambda/sub 0/ the vacuum wave length), and if further the guides are parallel, operating in the H/sub 10/ mode, and joined by a window at the center of their wide side. No power will then go into the forward end of the secondary guide (but of course power will be transmitted beyond the hole in the primary guide). This surprising effect is due to an interference of the excitation by the electric and by the magnetic field. Other cases are discussed. The power transmitted through a window in the side of a wave guide is, in the simplest cases, one half of the power transmitted through the same window at the end of the guide. The excitation of a coaxial line through a side window is calculated; the power transmitted into a coax will be somewhat larger than into a wave guide for the same window size.
- Research Organization:
- Massachusetts Inst. of Tech., Cambridge (USA). Radiation Lab.
- OSTI ID:
- 6023025
- Report Number(s):
- DOE/NBM-5005111; ON: DE85005111
- Resource Relation:
- Other Information: Paper copy only, copy does not permit microfiche production
- Country of Publication:
- United States
- Language:
- English
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