US 6,023,209 A · Coplanar microwave circuit having suppression of undesired modes

Abstract

Two or three conductor coplanar transmission lines and lossy coplanar resistive films are formed on a surface of a substrate. The resistive film dimensions and resistivity are selected to suppress various spurious electromagnetic modes within and around the substrate. The resistive films may be positioned along the outer edges of the transmission lines or between the transmission line conductors. The resistive film may have regular spaced openings for producing an average resistivity different than that of a continuous resistive film. In one embodiment, a signal conductor has a serpentine shape and resistive film elements are positioned between adjacent sections of the signal conductor. In another embodiment, interdigitated resistive film elements extend between transmission line conductors.

Claims69

Dependent claims

A coplanar circuit structure for suppressing spurious modes comprising:

an insulating substrate having a planar surface;
a coplanar transmission line including at least first and second spaced-apart coplanar strip conductors mounted on the substrate surface, the first and second conductors being spaced apart by a first gap;
a first resistive film disposed on the substrate surface and extending coplanar with, adjacent to and along a length of the first conductor;
and
a second resistive film disposed on the substrate surface and extending coplanar with, adjacent to and along a length of the second conductor;
the first and second resistive films being coupled to the first and second conductors for attenuating spurious modes.

3 more elements

Dependencies are inferred from the claim text.

Coplanar microwave circuit having suppression of undesired modes

Life of this patent

Coplanar microwave circuit having suppression of undesired modes

Life of this patent

Abstract

Claims69