Doesn't chaff work by being an aerial? And so it needs to be a certain length?

http://www.agriculturedefensecoalition.org/sites/default/fil...

> Chaff consists of aluminum-coated glass fibers (also referred to as dipoles) ranging in lengths from 0.8 to 0.75 cm.

> Figure 1. Radio frequency chaff cartridges (Air Force version RR-188/AL, top; Navy version RR-144/AL, bottom) and chaff fibers (right). Fibers of different lengths can be seen in the Navy operational version (clear cylinder). These lengths correspond to the frequency modes of the radar spectrum