Issue link: https://iconnect007.uberflip.com/i/1248324
66 PCB007 MAGAZINE I MAY 2020 Electrical Testing and Properties Analyzed A vector network analyzer utilizes a receiver to measure both the reflected input signal and the signal that passes through to the output of the device under test. It is then able to com- pare them to the known stimulus signal [1] . In our test case, the device under test would be our 50-ohm controlled impedance trace on the top layer, our via structure, including connec- tion method, and the 50-ohm controlled im- pedance trace on the bottom layer. In our test- ing, the following electrical properties of the interconnects were compared: return loss, in- sertion loss, impedance, and rise time degra- dation, each of which is described briefly in the following paragraphs. The electrical testing was completed by GateWave Northern Inc. Return loss and insertion loss typically cor- relate with one another in that if there is a high return loss, it will typically correlate to a low insertion loss. This is due to the fact that return loss is the loss of signal power due to signal reflection or return by discontinuity in the transmission line, while insertion loss is the loss of signal power along the transmission line [2] (Figure 13). With all things being simi- lar in our test vehicle (excluding the intercon- nect type), any difference in the insertion loss would be directly related to that interconnect type. The impedance measurement is the amount of opposition faced by the direct or alternating current when it passes through a circuit. Typi- cally, in PCB applications, impedance is mea- Figure 10: Z-axis view of the ISC International elastomer. Figure 11: Cross-section view 1 of the ISC International elastomer. Figure 13: Insertion loss vs. return loss [2] . Figure 12: Cross-section view 2 of the ISC International elastomer.