![Epsilon-Measurement-Probe-eMP Compass Technology Group's Epsilon Measurement Probe (eMP), which is a small tabletop fixture that measures dielectric permittivity from 30 MHz to 500 MHz](https://compasstech.com/wp-content/uploads/elementor/thumbs/Epsilon-Measurement-Probe-eMP-qoujfo7693l6yq98lqkxkwzr4ju53gdbnoa6eyxhzc.jpg)
The epsilon measurement probe (eMP) is a small, tabletop fixture that measures complex dielectric permittivity of bulk or sheet specimens from 30 MHz to 500 MHz. It consists of a short transmission line terminated in an open circuit. Material specimens are placed onto the small sensor embedded within a larger metal ground plane. CEM inversion then rapidly converts the measured S-parameter data into real and imaginary permittivity.