Flat Cable Characteristic Impedance Reduction and Measurement Techniques

Flat multiconductor cable of the type used for mass insulation displacement connection (i.d.c.) typically has a characteristic impedance (Z0) in the 90 to 150 Ω range. In some applications, it is desirable to have less than half this Z0. A properly configured four-conductor configuration allows us to achieve a low Z0. This technique is extendable to printed-wiring flexible-circuits (flex circuits) as well. The primary application for this four-conductor application is for differential low Z0 applications. Z0 measurements were made using both time-domain reflectometry (t.d.r.) methods and inductance-capacitance (LC) methods. Limitations of both measurement methods are briefly discussed. Lossless line equations are assumed. Flat multiconductor cable is frequently used in a ground-signal-ground-signal application. Measurements were made to determine the effects of different conductor placements. Wednesday, October 3, 2001 11 ANNUAL REGIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY Rocky Mountain Chapter of the IEEE EMC Society, at the Radisson Inn, Northglenn, Colorado. ☺ .R. Buhler Storage Technology Corporation MS 4274 One StorageTek Drive Louisville, Colorado 80028-4274 (303) 673-7109 [email protected]