Experimental Investigation on Phase Constant and Cutoff Wavelength of a Cocoon-Section Corrugated Waveguide

Kohshi ABE  Akira HASHIMOTO  

IEICE TRANSACTIONS (1976-1990)   Vol.E62   No.11   pp.762-767
Publication Date: 1979/11/25
Online ISSN: 
Print ISSN: 0000-0000
Type of Manuscript: PAPER
Category: Microwaves and Millimeter Waves

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This paper describes an experimental investigation on the phase constant and the cutoff wavelength of a cocoon-section corrugated waveguide (CCWG) with a cocoon-cross-section configuration and a sinusoidal-wave helical corrugation along the longitudinal axis at guide-walls. The CCWG is widely used for antenna feeder waveguides of the 4, 5, 6 and 7 GHz-band microwave communication systems. The purpose of this investigation is to get a useful means for an easy design of the corrugated waveguide. We have measured resonance frequencies of cavities made of 4, 6 and 7 GHz-band CCWGs at frequencies between 3 and 8 GHz by means of a resonant cavity method. As an example of results, the measured phase constant of the 4 GHz-band CCWG is a few percents larger at the frequency range 3.64.2 GHz than the calculated one of a cocoon-section smooth waveguide (CSWG) with a tube diameter equivalent to the center diameter of corrugated guide-walls. And the measured cutoff wavelength is nearly equal to the calculated value of the CSWG. As a result of this investigation, the experimental equation showing a dispersive property of the phase constant of the CCWG is led assuming that the corrugation size is small as compared with the major diameter.