On the design of multimode integrated circuits in multilayered processes

The contemporary way to make telecommunication circuits is based on a differential approach, consisting of doubling the single-ended circuit. This results in a perfectly symmetrical structure with a doubled part count and twice the size. In this paper, a new design methodology based on coupled inductors is introduced, resulting in a part count for the differential circuit equalling that of the single-ended circuit with an almost unchanged chip area. At the same time, due to a higher magnetic flux, the quality factor of the new inductors is enhanced up to 40 % compared to a conventional inductor. To verify the proposed theory, experimental results of two semiconductor integrated circuits are presented, showing a very good agreement with the simulated results.