Optimization of Optically and Electrically Modulated Scattering Probes for Field Measurements

In this paper, the problem of optimizing probes used in modulated scattering systems is examined. Instead of the usual empirical or blind numerical optimization, a simple analytical formulation is developed, uniquely based on the impedance states of the modulating devices. This formulation allows obtaining some bounds on system performances and assessing the sensitivity to frequency and component characteristics variations. In particular, an optical modulation component, providing an advantage in terms of low invasiveness, is compared with the more common p-i-n diode-based modulators. The validity of the proposed approach, for high-resolution electrically small probes is demonstrated numerically and experimentally.