Bridged-t filter

Claim 1

A NARROW BAND REJECTION FILTER DEVICE COMPRISING A SINGLE MONOLITHIC CRYSTAL OF SEMICONDUCTOR MATERIAL HAVING A FIRST REGION OF ONE TYPE OF SEMI-CONDUCTIVITY AND A SECOND REGION OF A SECOND TYPE OF SEMICONDUCTIVITY, SAID REGIONS BEING IN JUXTAPOSED RELATION PROVIDING A RECTIFYING P-N JUNCTION, SAID SECOND REGION EXTENDING BEYOND THE AREA OF SAID JUNCTION, FIRST AND SECOND OHMIC CONTACTS SPACED APART A SELECTED DISTANCE ON THE OUTER SURFACE OF SAID FIRST REGION PROVIDING A RESISTIVE CURRENT PATH OF SELECTED RESISTIVE IMPEDANCE, SAID RESISTIVE PATH IN COOPERATION WITH SAID JUNCTION FORMING A DISTRIBUTED CAPACITANCE, SAID FIRST REGION BEING HIGHLY DOPED WITH IMPURITY CONCENTRATION RAPIDLY DECREASING WITH DEPTH FROM THE OUTER SURFACE, SAID SECOND REGION BEING LIGHTLY DOPED WITH IMPURITIES SUBSTANTIALLY UNIFORMLY DISTRIBUTED IN SAID SECOND REGION, A THIRD OHMIC CONTACT ON THE OUTER SIDE OF SAID SECOND REGION AND BEING SUBSTANTIALLY COEXTENSIVE IN AREA WITH SAID P-N JUNCTION, SAID THIRD OHMIC CONTACT SERVING, EFFECTIVELY, AS A COMMON TERMINAL FOR THE DISTRIBUTED CAPACITANCE AND FOR ONE END OF A NON-DISTRIBUTED RESISTIVE IMPEDANCE CONSTITUTED BY SAID EXTENSION ON SAID SECOND REGION, AND A FOURTH OHMIC CONTACT ON SAID SECOND REGION SEPARATED FROM SAID THIRD OHMIC CONTACT, SAID FIRST REGION BEING PROPORTIONED TO PROVIDE A SELECTED RATIO OF DISTRIBUTED RESISTIVE IMPEDANCE BETWEEN SAID FIRST AND SECOND CONTACTS TO THE NON-DISTRIBUTED RESISTIVE IMPEDANCE BETWEEN SAID THIRD AND FOURTH CONTACTS WHICH IS SUBSTANTIALLY 17.79:1 TO PROVIDE A SELECTED NULL FREQUENCY WHICH WILL BE A FUNCTION OF THE DISTRIBUTED RESISTANCE AND CAPACITANCE AND THE LENGTH OF THE ELECTRICAL PATH BETWEEN SAID FIRST AND SECOND OHMIC CONTACTS.