Investigation of shorting vias for suppressing common-mode radiation in different frequency range

The effects of shorting vias on suppressing common-mode radiation in different frequency range are investigated based on a typical wire-bonded ball grid array (WB-BGA) package. Conventional shorting vias provide a short return path for common-mode currents so as to reduce the radiation effectively at low frequencies. However, the suppression is limited at higher frequencies due to the excess parasitic inductance. Therefore, a novel concept of absorptive shorting vias is presented for suppressing radiation in high frequency range.