A broadband common-mode filter composed of three layers of a printed circuit board (PCB) with $\mathbf{5.2} \text{mm} \times 17.6 \text{mm}$ area is proposed. Multiple transmission zeros can be created by aT-type resonator on the second PCB layer with a differential pair on the first PCB layer. The broadband common-mode noise suppression can be achieved by positioning transmission zeros appropriately. ANSYS HFSS is used to verify the design of proposed filter and the simulation result shows the common-mode noise is suppressed over 10 dB from 2 GHz to 10.5 GHz with 136% fractional bandwidth. The differential signal keeps good integrity in the frequency range from DC to 12 GHz.
