On-chip millimeter wave Lange coupler

1. A balanced amplifier, comprising:

a first Lange coupler structured to divide an input signal fed into the first Lange coupler into two signals and structured to output the two signals with a phase shift to each other;

a plurality of amplifiers structured to amplify the two signals;

a second Lange coupler structured to reverse the phase shift of the two signals and to combine the amplified two signals output from the plurality of amplifiers in phase, wherein each of the first and second Lange couplers includes:

a first plurality of lines on a first level; and

a second plurality of lines on a second level, each of the second plurality of lines on the second level corresponding with a line from the first plurality of lines on the first level;

wherein at least two lines on the first level are coupled to at least two lines on the second level, wherein each of the at least two lines on the first level is coupled to at least one non-corresponding line on the first level and at least one non-corresponding line on the second level, and

wherein the coupling of the at least two lines on the first level to the at least two lines on the second level form at least two sets of shorted lines extending between the first level and the second level, a first set of shorted lines having an end in the first level and an opposite end in the second level, a second set of shorted lines having an end in the first level and an opposite end in the second level, the coupling of the first set of shorted lines to the first level and the second level forming a cross-coupling configuration with the coupling of the second set of shorted lines to the first level and the second level.

2. The balanced amplifier of claim 1 , wherein the first level is higher than the second level.

3. The balanced amplifier of claim 1 , wherein the first and second plurality of lines are made of metal.

4. The balanced amplifier of claim 1 , wherein cross-sections of the lines of the first plurality of lines are substantially identical,

wherein cross-sections of the lines of the second plurality of lines are substantially identical, and

wherein the cross-sections of the lines of the first plurality of lines are larger than the cross-sections of the lines of the second plurality of lines.

5. The balanced amplifier of claim 1 , wherein each of the Lange couplers further comprises a substrate into which the first and second plurality of lines are etched so as to define respective on-chip Lange couplers.

6. The balanced amplifier of claim 1 , wherein the at least two lines on the first level are coupled to the at least two lines on the second level via electromagnetic waves traveling through the first and second plurality of lines.

7. The balanced amplifier of claim 6 , wherein the electromagnetic waves are millimeter waves.

8. The balanced amplifier of claim 1 , further comprising at least two strips to respectively connect the at least two lines on the first level to the at least two lines on the second level in a cross-coupled configuration.

9. The balanced amplifier of claim 1 , wherein the at least two lines on the first level and the at least two lines on the second level are each coupled horizontally.

10. The balanced amplifier of claim 1 , wherein each of the at least two lines on the first level are coupled vertically to a corresponding line on the second level.

11. The balanced amplifier of claim 1 , wherein ends of each of the first plurality of lines on the first level are unconnected with each other, and ends of each of the second plurality of lines on the second level are unconnected with each other.