Yu‐Chang Pai and Shou‐kuo Sogo Hsu
The purpose of this paper is to present the problem of high‐speed data transmission on flexible printed circuits (FPC) and the common method for transmission signal designs on…
Abstract
Purpose
The purpose of this paper is to present the problem of high‐speed data transmission on flexible printed circuits (FPC) and the common method for transmission signal designs on those FPCs. A new and novel approach using a “voided return path” of the coplanar transmission model is described and the ease of building them in mass production is described.
Design/methodology/approach
Microstrip transmission structures with a “mesh” return were studied and illustrated with emphasis on the problems encountered when the signal changes direction. A new solution using the “voided” return layer of the coplanar transmission model was proposed, simulated, built and tested.
Findings
The use of this novel coplanar structure to solve the problem of gigabit data transmission, with minimum noise and electromagnetic interference on flexible circuits can be achieved at low cost and with the flexibility to have multiple impedances and application for “Dynamic Flex”.
Research limitations/implications
The “voided” coplanar structure has been used successfully. Further, developments are underway to employ a “modified” broadsided‐coupled differential structure that simulated a “twisted pair”.
Originality/value
The paper describes various high‐speed transmission structures on FPC used in computers and servers, combined with high volume mass‐production techniques. It presents the best cost scenario for optimal PCB design flexibility and applications.