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# Phase Stable Waveguide

IP.com Disclosure Number: IPCOM000090707D
Original Publication Date: 1969-Jun-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 59K

IBM

## Related People

Kramer, E: AUTHOR

## Abstract

Ridged waveguides have a very desirable temperature stability characteristic. A typical ridged waveguide has a structure similar to that in drawing 1. A waveguide of the indicated geometry has the desirable characteristic of maintaining a constant phase shift along its length over a wide range of temperature variations when such waveguide is operated at a frequency, determined by its physical size.

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Phase Stable Waveguide

Ridged waveguides have a very desirable temperature stability characteristic. A typical ridged waveguide has a structure similar to that in drawing 1. A waveguide of the indicated geometry has the desirable characteristic of maintaining a constant phase shift along its length over a wide range of temperature variations when such waveguide is operated at a frequency, determined by its physical size.

For a given waveguide, the frequency at which it exhibits the temperature stable characteristic can be determined. Since the dimensions of the waveguide are known, the ratios s/a, d/b, and b/a can also be determined. From drawing 3, using the known ratios of s/a and d/b, it is possible to calculate the compensation angle 8 . From drawing 2, knowing the ratios of s/a and d/b and further assuming a ratio of b/a = .45, it is possible to calculate the cutoff wavelengths over width or lambda(c)/a. It is further recognized that sine theta(p) = lambda(p) /lambda(c). Since 8 and lambda(c) are calculable, lambda(p) can also be calculated from the above equation. The frequency at which the waveguide is temperature stable is then expressed by the equation f(p) = c/lambda(p).

It can also be desirable to arrange a waveguide having the temperature stable characteristic at a given frequency. For such a waveguide, the ratios s/a, d/b, and b/a must be selected. From drawing 3 theta(p) is determined. From drawing 2, lambda(c)/a is also determined. Since the freque...