Portable Dielectric Measurement Kit0 pages

Short technical notes

Portable Dielectric Measurement Kit
Dielectric Materials have many applications ranging from microwave components and subsystems to industrial and
manufacturing processes. The precise knowledge of the dielectric properties of these materials is very important for
industrial as well as scientific microwave applications success.

Fig. 1. The Portable Dielectric Measurement Kit (PDMK) with the container for measurement of liquids and powders

The Portable Dielectric Measurement Kit (PDMK) is a new instrument designed to determine the complex
permittivity for a wide range of solid, semi-solid, granular and liquid materials around the ISM frequency of 2.45
GHz. Unlike other instruments, it performs automatically all the necessary control functions, generation and
analysis of microwave signals, data processing, dielectric calculation, storage and display of results. The PDMK is
able to measure low, moderate and high loss dielectric materials with the same set-up.

Measurement Principle
Fig 3. Labview-based Control Pannel

The dielectric measurement probe has been designed as an openendend coaxial resonator probe (see Figs. 1 and 2) where the
microwave signals interact with the material.
When the material is touching the open resonator, electromagnetic fields
fringe into the material under test (DUT) and change due to the dielectric
properties of the sample, affecting the signal reflected back to the
resonator. From these reflection measurements, the resonant frequency
and quality factor are determined and related with the dielectric
properties by using an in-house developed numerical procedure.

Fig 2. Sensor tip with microwaves
interacting dielectric material.