High frequency attenuator with constant phase shift

Claim 1

IN AN ATTENUATING APPARATUS FOR VARYING THE ATTENUATION OF HIGH FREQUENCY ENERGY PASSING THERETHROUGH, WHEREIN THE APPARATUS INCLUDES A COAXIAL TRANSMISSION LINE WITH A SLOT AXIALLY COMPLETELY THROUGH BOTH INNER AND OUTER CONDUCTORS OF THE LINE, THE IMPROVEMENT COMPRISING: AN ATTENUATOR PLATE OF UNIFORM CROSS-SECTION AND FORMED OF DIELECTRIC MATERIAL, MEANS MOUNTING THE ATTENUATOR PLATE EXTENDING ENTIRELY THROUGH THE SLOT IN BOTH INNER AND OUTER CONDUCTORS OF THE TRANSMISSION LINE FOR MOVEMENT TO DISPOSE DIFFERENT PORTIONS OF THE PLATE IN THE SLOT, AND A RESISTIVE COATING UPON THE ATTENUATOR PLATE IN A PATTERN TO PROVIDE A CONTROLLABLE AMOUNT OF RESISTIVE COATING WITHIN THE TRANSMISSION LINE WHILE ALWAYS MAINTAINING A CONSTANT PORTION OF SAID PLATE WITHIN SAID LINE, SAID AMOUNT VARYING IN ONE DIRECTION CONTINUOUSLY AS SAID PLATE IS MOVED IN ONE DIRECTION THROUGH SAID LINE, TO THEREBY PROVIDE A CAUSING A VARYING AMOUNT OF ATTENUATION OF SAID ENERGY WITHOUT SUBSTANTIALLY CHANGING THE PHASE OF TRANSMITTED ENERGY WITH CHANGES IN ATTENUATION.