Capacitor SERIES RESISTANCE ESR

i want to measure capacitor ESR , i am doing it by analysing it on VNA and observing s11 parameter . where can i locate resonance point? and calculate ESR OF CAPACITOR?

Capacitor series resonance with ESL shows as a real S11 value near (-1, j0). Many modern VNA will directly calculate and display C and ESR in single port measurement, also below the resonance frequency.

usually i use a capacitor's ESR to determine the loaded Q in bandpass filters. So to measure Q of an unknown component, i make up a top coupled single resonator bandpass filter, measure the bandwidth, and determine the capacitor ESR from that measured S21 data. The single pole filter's bandwidth shape and midband insertion loss are very sensitive to component Q, so it makes it easy to measure.