Ultrahigh isolation stripline circuit

A structure comprising:

• a first signal trace embedded in a dielectric layer;
• an upper ground plane on a first surface of the dielectric layer;
• a lower ground plane on a second opposing surface of the dielectric layer;
• a first pair of vias wherein each via connects the first signal trace to a separate contact pad within an antipad on one of the first or second surfaces of the dielectric layer;
• and
• a first continuous conducting ground shield wall, in the dielectric layer, that surrounds the first signal trace and the first pair of vias and electrically connects the upper and lower ground planes, such that the first signal trace and the first pair of vias are completely enclosed, except for the antipads, within a continuous conducting ground shield formed of the first ground shield wall and the portions of the upper and lower ground planes within the first ground shield wall.

A method comprising:

• on a double-clad circuit material having a first metal (M1) layer, a second metal (M2) layer, and a dielectric core, patterning and etching a signal trace in the M2 layer that includes a first contact pad at one end of the signal trace and a second contact pad at the other end of the signal trace;
• laminating the dielectric face of a single-clad circuit material to the M2 layer, wherein the metal layer of the single-clad circuit material forms a third metal (M3) layer;
• routing a first trench between the M1 layer and the M3 layer on a first side of the signal trace;
• lining the first trench with a conductive liner such that the M1 and M3 layers are electrically connected;
• routing a second trench between the M1 layer and the M3 layer on a second side of the signal trace;
• lining the second trench with a conductive liner such that the M1 and M3 layers are electrically connected;
• whereby the signal trace is enclosed within a continuous conducting ground shield formed of the first lined trench, the second lined trench, the M1 layer, and the M3 layer.

A method comprising:

• forming a first pair of vias that electrically connect a first metal (M1) layer and a second metal (M2) layer of a double-clad circuit material;
• patterning and etching a first signal trace in the M2 layer that electrically connects the first pair of vias;
• laminating the dielectric face of a single-clad circuit material to the M2 layer, wherein the metal layer of the single-clad circuit material forms a third metal (M3) layer;
• routing a continuous first trench between the M1 layer and the M3 layer that surrounds the first signal trace and the first pair of electrically conducting vias;
• lining the trench with a conductive liner such that the M1 and M3 layers are electrically connected;
• etching a first pair of antipads in the M1 layer to form contact pads for the first pair of electrically conducting vias;
• whereby the first signal trace and the first pair of vias are completely enclosed, except for the antipads, within a continuous conducting ground shield formed of the lined trench and the portions of the M1 and M3 layers surrounded by the routed trench.