Circuit board and method of manufacturing thereof

A method of manufacturing a circuit board, comprising:

• providing a first dielectric substrate;
• forming a plurality of first recesses in the first dielectric substrate such that the first dielectric substrate comprises a base, a first elevated platform and a plurality of second elevated platforms, wherein the first elevated platform and the plurality of second elevated platforms protrude from the base and are spaced apart from each other by the plurality of first recesses, and the base is exposed in the plurality of first recesses;
• forming a signal line on the base and the first elevated platform;
• providing a second dielectric substrate;
• forming a second recess in the second dielectric substrate;
• bonding the first dielectric substrate and the second dielectric substrate such that the plurality of the first recesses and the second recess merge to form a space, wherein the signal line is positioned in the space;
• and
• disposing a pair of ground wires between the first dielectric substrate and the second dielectric substrate such that a first segment of the signal line which is disposed on the first elevated platform is coplanar with the pair of ground wires, and a projection of a second segment of the signal line which is disposed on the base on the first dielectric substrate partly overlaps projections of the pair of ground wires on the first dielectric substrate.