Single-band Series Absorptive Common-mode Noise Filter

Abstract

A Single-band Series Absorptive Common Mode Noise Filter (ACMF) is proposed. The ACMF is embedded in a four-layer printed circuit board (PCB) and consists of three parts: a Reflective Common Mode Noise Filter (RCMF), a matching circuit, and an absorber. The RCMF is designed using mushroom-type resonators. The matching circuit is designed using meander lines to reduce the size of the filter dimensions. The absorber of the Common Mode noise (CM) is a series resistor. The designed operating frequency is 2.45 GHz. The simulation results are as follows: the insertion loss of CM (Scc21) is -22.49 dB at the frequency of 2.61 GHz, the return loss of CM (Scc21)  is -18.62 dB at the frequency of 2.5 GHz, while the integrity of the Differential Mode signals (DM) can be maintained with a very small insertion loss (Sdd21) of -1 dB at the frequency range of 0-8 GHz, and the achieved Absorption Efficiency (AE) is 93% at the frequency of 2.54 GHz. The proposed ACMF dimension is 10.3 x4.6 mm. The fractional bandwidth is 19%. The measurement results of the fabricated ACMF do not deviate significantly the simulation results. They are as follows: Scc21 is -17.87 dB at the frequency of 2.31 GHz, Scc11 is -20.87 dB at the frequency of 2.38 GHz, Sdd21 is -2.8 dB at the frequency range of 0–8 GHz, the Absorption Efficiency is 97% at the frequency of 2.32 GHz, and the fractional bandwidth is 17%. Therefore, the results of the ACMF design carried out by simulation can be implemented into a fabricated ACMF with measurement results similar to the calculation results in the design.