The reduction of electromagnetic interference in RF integrated circuits through the use of metalized substrates

This paper discussed the use of metalized substrates for coupling (EMI) reduction of integrated circuit components. Coupled microstrip lines with arrays of shorting vias or mushrooms were used for demonstration. It was found that the metalized substrate could reduce the circuit coupling at lower frequencies due to the shielding effect and enhance the coupling at much higher frequencies due to the scattering and radiation of the metalized substrate. It was also found that the use of metalized EBG elements over the entire substrate, although eliminating the surface wave, would enhance the circuit coupling by introducing additional capacitance between strips at higher frequencies. At lower frequencies, the inductive vias are effectively shorted to the ground and provide shielding to reduce circuit coupling.