Dielectric supports for high frequency coaxial lines

Claim 1

AN INTERNAL DIELECTRIC SUPPORT FOR COAXIAL LINES, SAID SUPPORT DEFINING A CENTRAL AXIS, A CENTRAL APERTURE CONCENTRIC WITH SAID AXIS FOR HOLDING THE INNER CONDUCTOR OF THE LINE, AN OUTER SURFACE FOR CONTACTING THE INNER WALL OF THE OUTER CONDUCTOR OF THE LINE, AND FIRST AND SECOND ENDS FOR DETERMINING THE AXIAL LENGTH OF SAID SUPPORT; AND HAVING MEANS, FORMING AN INTEGRAL PART OF SAID SUPPORT, FOR SHIFTING THE RESONANCE OF AT LEAST ONE OF THE TWO UNDESIRED MODES OF PROPAGATION OCCURING WITHIN THE SUPPORT, THE TE AND TM MODES, TO A SHORTER WAVELENGTH, THEREBY REDUCING THE ASSOCIATED ELECTRICAL REACTANCES OVER THE USEFUL BANDWIDTH OF THE LINE AND CONSEQUENTLY REDUCING, OVER THE SAME BANDWIDTH, THE REFLECTION CAUSED BY THE SUPPORT IN CONSEQUENCE OF THE SAID ASSOCIATED REACTANCE, SAID MEANS IS AT LEAST ONE SPIRAL GROOVE, OF WHICH THE PITCH H IS DEFINED AS $$H>O, SAID AT LEAST ONE GROOVE EXTENDING AT LEAST ALONG SUBSTANTIALLY THE ENTIRE AXIAL LENGTH OF THE SUPPORT, OPENING ONTO SAID OUTER WALL, AND HAVING A DEPTH R DEFINED AS R$I, WHERE I IS THE DISTANCE FROM SAID OUTER SURFACE TO SAID CENTRAL APERTURE, AS MEASURED ALONG A LINE INTERSECTING SAID CENTRAL AXIS AND PERPENDICULAR THERETO.