摘要 |
In the method, particles (16) are classified by locating them in a resonance cavity (10) and applying a swept range of microwave radiation to the cavity. The transmitted signals are detected and analysed. The particle is then assigned to a classification in accordance with changes in the dielectric characteristics of the cavity as a result of the presence of the particle. The radiation is polarised and is applied in at least two mutually orthogonal directions. With the particle located at the centre of the cavity, where the E-field is a maximum, and with signals propagating in at least two mutually orthogonal direction, account is taken of dimensional and orientational inaccuracies from particle to particle. <IMAGE> |