A Novel Circuit Architecture of Bidirectional Common-Mode Noise Absorption Circuit

Techniques of common-mode (CM) noise absorption have been developed in recent years, but very few of them can achieve CM bidirectional absorption. This article proposed a novel circuit architecture that can provide bidirectional CM noise absorption theoretically, meaning that the circuit can absorb CM noises from both sides of differential channels. The essential concept is to design the even-even and even-odd modes of the proposed circuit individually, and by doing so, the bidirectional absorption can be easily realized in a mathematically sound way. In this article, analytical design equations are derived completely, and synthesis procedure is listed in detail. Then, two bidirectional absorptive CM filters are implemented based on the proposed circuit. One of them is fabricated by the printed circuit board process and the other one is fabricated by the integrated passive device process. These two implementations reveal the flexibility of the proposed circuit. Finally, measured results are given as verification, and a comparison table with previous works is demonstrated.