This paper presents a thin-wire electromagnetic (EM) model of multi-propeller drone that generates drone micro-Doppler pattern efficiently as a function of radar parameters and propeller properties. Experimental results of propeller micro-Doppler pattern measured in anechoic chamber was investigated and used to validate the results produced by thin-wire model of single propeller in S-band and X-band. Then the thin-wire model was expanded to multi-propeller drones and reproduced linear micro-Doppler patterns of multi-propeller drone measured by radar system in long Coherent Processing Interval (CPI) circumstance. The model-based replica was shown to be useful in radar micro-Doppler analysis of multi-propeller drones, especially to study the influence of propellers synchronisation and in long CPI circumstances.