| 摘要 |
1,036,846. Waveguides. WESTERN ELECTRIC CO. Inc. June 20, 1963 [June 26, 1962], No. 24564/63. Heading H1W. Generation of unwanted modes in a waveguide taper is reduced by providing a low-loss dielectric member at a position where the electric field-intensity of the unwanted mode is low and the intensity of the wanted mode is high. The invention may be applied to wave guides designed for transmission of the circularelectric TE 01 mode having tapered transmissions designed according to the methods described in Specification 883,179 and in the article " Circular Waveguide Taper of Improved Design," published in the Bell System Telephone Journal, July, 1958. Such a taper 12 is provided with a dielectric sleeve 13 supported, e.g. by dielectric discs 14, 15. Suppression of the TE 02 mode is achieved if the average radius b of the sleeve at a point is related to the taper radius a at that point by b/a=k 1 /k 2 , where k 1 and k 2 are roots of the Bessel junction of the first kind and order and are equal to 3À832 and 7À016 respectively. The thickness of the sleeve may be constant or may vary as 1/a. A further sleeve may be added, designed to prevent generation of the TE 03 mode. The tapers may consist of helical waveguide as described in Specification 883,439. The Specification contains a theoretical discussion of the invention. |
