Microwave filter utilizing two resonant rings and having terminals permitting use to band pass or band reject

Claim 1

A MICROWAVE FILTER HAVING A FIXED CENTER FREQUENCY OF OPERATION COMPRISING: (A) A FIRST CIRCULAR RING CONDUCTING NETWORK HAVING A CIRCUMFERENCE SUBSTANTIALLY EQUAL TO ONE AND A HALF TIMES THE WAVELENGTH OF A SIGNAL HAVING A FREQUENCY EQUAL TO THE CENTER FREQUENCY OF OPERATION OF THE FILTER; (B) A SECOND CIRCULAR RING CONDUCTING NETWORK IDENTICAL IN CIRCUMFERENCE TO SAID FIRST RING NETWORK; (C) AN INPUT TERMINAL CONNECTED TO ONE POINT ON SAID FIRST CONDUCTING RING; (D) A SECOND TERMINAL CONNECTED TO SAID FIRST CONDUCTING RING AT A POINT DIAMETRICALLY OPPOSITE TO THE POINT AT WHICH SAID INPUT TERMINAL IS CONNECTED; (E) A THIRD TERMINAL CONNECTED TO SAID SECOND CONDUCTING RING; (F) A FOURTH TERMINAL CONNECTED TO SAID SECOND CONDUCTING RING AT A POINT DIAMETRICALLY OPPOSITE TO THE POINT AT WHICH SAID THIRD TERMINAL IS CONNECTED; (G) A CONDUCTING STRIP HAVING A LENGTH EQUAL TO ONEQUARTER OF THE WAVELENGTH OF A SIGNAL HAVING A FREQUENCY EQUAL TO THE CENTER FREQUENCY OF OPERATION OF THE FILTER AND HAVING ONE END CONNECTED TO SAID FIRST RING AT A POINT ONE-QUARTER OF A WAVELENGTH AWAY FROM SAID INPUT TERMINAL AND ITS OTHER END CONNECTED TO SAID SECOND CONDUCTING RING AT A POINT ONE-QUARTER OF A WAVELENGTH AWAY FROM SAID THIRD TERMINAL; AND (H) A SECOND CONDUCTING STRIP HAVING A LENGTH EQUAL TO ONE-QUARTER OF THE WAVELENGTH OF A SIGNAL HAVING A FREQUENCY EQUAL TO THE CENTER FREQUENCY OF OPERATION OF SAID FILTER AND HAVING ONE END CONNECTED TO SAID FIRST RING AT A POINT ONE-QUARTER OF A WAVELENGTH AWAY FROM SAID SECOND TERMINAL AND ITS OTHER END CONNECTED TO SAID SECOND RING AT A POINT ONE-QUARTER OF A WAVELENGTH AWAY FROM SAID FOURTH TERMINAL.