An ESL-Cancelling Circuit for a Shunt-Connected Film Capacitor Filter Using Vertically Stacked Coupled Square Loops

An ESL-cancelling circuit for a shunt-connected film capacitor filter using vertically stacked coupled square loops is reported in this paper. The applicable whose equivalent series inductance (ESL) of the shunt-path causes deterioration performance at frequencies above self-resonant frequency. Two pairs magnetically are used those can equivalently add negative to cancel ESL improvement performance. 1-μF was designed according Biot-Savart law and electromagnetic (EM)-analysis, prototype fabricated with an FR4 substrate. measured result showed 20-dB frequency as designed, satisfying Sdd21 less than -40 dB 1 MHz 100 MHz. This almost reduce nH also difficult realize any kind single bulky without cancelling ESL.