Numerical Simulation and Models for Microcoaxial Probes. Application to "In Vivo" Measurements of Dielectric Parameters of Biological Media in the Microwave Band (1-12 GHz)

In vivo measurements of the complex permittivity ε* = ε' - jε" imply appropriate investigation methods. In this direction, we present an input measurement method associated with microcoaxial probes which seems well adapted to this problem. Considering the probe as a small monopole antenna, we derive relations giving ε' and ε" from the measured input impedance of the probe, including a correction term taking into account a finite dimension ground plane. Then we give some numerical simulation for different probes v.s frequency and experimental results obtained on phantom materials and on a beef muscle in the microwave band 1-12 GHz.