Daily Image
06-10-2014
Measuring dielectric constant and loss of foam materials
| Submitter: | Michel Arts |
| Description: | One of the work packages (WP3) of the SKA-TSM project (Technology for advanced Systems and bio-based Materials) deals with sustainable and cost-efficient designs and production processes. A part of this work package consists of the investigation of bio-based foam materials. These can be used as a support structure or as a radome for the Mid Frequency Aperture Array (MFAA). The relevant electrical properties of these materials are the dielectric constant and the loss tangent. These are measured using a rectangular cavity. To investigate a material, the resonance frequency and quality factor of the cavity are measured first while empty, and then while filled with the material under test. The shift of the resonance frequency is a measure for the dielectric constant of the material. Since the quality factor is a measure for the conductive losses of the cavity, the "empty" and "filled" values can be used to calculate the loss tangent of the material under test, which is a measure for the loss of the material. The pictures show a cavity, together with the measurement setup, and a more detailed view of the cavity. The latter consists of an aluminum box with a removable lid. To avoid RF-leakage from the (narrow) slot between box and lid, copper tape is used to close this slot. |
| Copyright: | ASTRON |
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