Dielectric Constants of Base Materials (Prepregs & Cores)

Impedance control of test coupons with the Sequid time domain reflectometer STDR-65In modern production processes it is common to press prepregs & cores to multilayer PCBs which underlie non-negligible fluctuations. These on one hand stem from inhomogeneous material para­meters and on the other hand from the manu­facturing process itself. Many PCB manu­factu­rers produce polished cut images and combine the knowledge about the exact geometry with controlled impedance trace measurements in order to determine the dielectric constant of the materi­als. However, this procedure causes high efforts in respect of time and is therefore costly.

Sequid's novel dual-line technology incorporated in the software module εbase facilitates identifying the dielectric constant of your substrates. This information is highly valuable in controlled impedance trace manufacturing. This kind of measure­ment bases on the extremely high time base stability of the DTDR-65 resp. STDR-65. Hence, the user saves valuable time by applying this efficient and precise technology to characterize base materials.

In many cases it does not suffice to determine the dielectric constant as scalar value, because the frequency dependency is inherently neglected - especially in appli­cations requiring controlled impedance traces in the GHz frequency range this can be crucial.

By means of the innovative software module εplus it is now possible to acquire the frequency dependent dielectric constant of your prepreg and core materials instantly. The unique combination of Sequids highly precise time domain reflectometers (DTDR-65/STDR-65) and the novel dual line technology enables the determination of material parameters from the MHz range up to 5GHz and beyond.

Required accessories for dielectric constant measurements