Transmission line filter having coupling extending quarter wave length between strip line resonators

Claim 1

A STRIP TRANSMISSION LINE COUPLER FOR A PROPAGATING WAVE HAVING A GIVEN WAVE LENGTH COMPRISING FIRST AND SECOND ADJACENT STRIP TRANSMISSION CIRCUIT PLANES POSITIONED IN A STACKED ARRAY, SAID FIRST CIRCUIT PLANE INCLUDING A GROUND PLATE AND A FILTER SECTION SPACED FROM SAID GROUND PLATE, MEANS FOR CONNECTING ONE EDGE OF SAID FILTER SECTION TO SAID GROUND PLATE, MEANS FOR CONNECTING THE OPPOSITE EDGE OF SAID FILTER SECTION TO A STRIP TRANSMISSION LINE IN SAID FIRST CIRCUIT PLANE, SAID SECOND CIRCUIT PLANE INCLUDING A GROUND PLATE AND A FILTER SECTION SPACED FROM THE GROUND PLATE OF SAID SECOND CIRCUIT PLANE, AND MEANS FOR CONNECTING ONE EDGE OF SAID FILTER SECTION TO THE GROUND PLATE OF SAID SECOND CIRCUIT PLANE, MEANS FOR CONNECTING THE OPPOSITE EDGE OF SAID FILTER SECTION TO A STRIP TRANSMISSION LINE IN SAID SECOND CIRCUIT PLANE, SAID FILTER SECTIONS BEING SPACED APART AND DISPOSED IN ALIGNED RELATIONSHIP WITH RESPECT TO EACH OTHER AND INTERPOSED BETWEEN SAID GROUND PLATES AND HAVING A LENGTH IN THE DIRECTION OF WAVE PROPAGATION EQUAL TO AN ODD MULTIPLE OF A QUARTER OF THE WAVELENGTH OF THE PROPAGATING WAVE.