Millimeter-Wave Multi-Layer Common-Mode Filter Based on Defected Ground Structure

This paper proposes an innovative multi-layer millimeter-wave broadband common-mode filter (CMF). The equivalent circuit of defected ground structure (DGS) expressed by transmission line model is provided and analyzed. The simulated results agree well with the full-wave simulation results. To avoid electromagnetic (EM) shielding effects, multi-layer circuit design is given to make it applicable for practical manufacture. For the proposed common mode filter, the corresponding 10.9-GHz common-mode (CM) stopband bandwidth covers 21.5-32.4 GHz. Moreover, the 3-dB differential mode (DM) cutoff frequency can reach up to 38.7 GHz.