Antenna matching circuitry for connecting antenna to signal output of communication circuit of near field communication reader used in vehicle, has symmetrical Pi-filtering circuit, inductances, coils, resistors and capacitors

摘要

The antenna matching circuitry (3) has a EMC filter (6), a symmetrical Pi-filtering circuit (7), several critical parasitic inductances, several serial working spacer inductances, coils (L3,L4), several resistors (R1,R2,R5), and several capacitors (C1-C9,C20,C30).