THREE-LEVEL BALUN AND ITS MANUFACTURING METHOD

摘要

A three-level semiconductor balun (10) is disclosed. In one embodiment, the balun (10) includes a first spiral-shaped transmission line (14) overlying a substrate. The first transmission line (14) has first and second ends. A second spiral-shaped transmission line (13) is substantially vertically aligned with the first transmission line (14). The second transmission line (13) has a first end electrically connected to the second end of the first transmission line (14). A third spiral-shaped transmission line (12) is substantially vertically aligned with the first and second transmission lines (14,13). The third transmission line (12) has a first end electrically connected to a second end of the second transmission line (13). The balun (10) may be integrated on the same chip with other RF circuit components, and is suitable for use at higher frequencies than most conventional baluns.