How to optimize the power line carrier filter circuit in a PLC?

Optimizing the power line carrier filter circuit for a PLC requires addressing three aspects: frequency response, insertion loss, and component parameters. A multi-stage filtering architecture is employed. The first stage is a broadband EMI filter, using a CMZ3225A-510T common-mode inductor and two X2 safety capacitors (0.1μF) to form an LC filter. The second stage is a bandpass filter, with its center frequency precisely matched to the carrier frequency, using a high-Q inductor CMZ2012A-900T resonant with an NPO ceramic capacitor (accuracy ±1%). The inductor core material is optimized, selecting low-loss ferrite such as PC44 to reduce high-frequency losses. Low-ESR C0G dielectric capacitors are used to improve filtering performance. Simulation software is used for circuit optimization, adjusting component parameters to achieve a flat passband and a stopband attenuation greater than 40dB. In actual testing, a network analyzer is used to verify the filter's S-parameters, ensuring an insertion loss of less than 1dB and a return loss greater than 20dB for optimal filtering performance.