A Termination Scheme for High-Speed Pulse Propogation on a System of Tightly Coupled Coplanar Strips

A realistic termination scheme is proposed for closely coupled N-conductor microstrips. The design aims to achievesatisfactorily low signal reflection and good fabrication feasibilityfor the planar MMIC (Monolithic Microwave Integrated Circuit)process. The matched termination network (MTN) for a losslessthree-line coupled microstrip structure is presented. High-speed pulse transmission along terminated tightly coupled microstriplines is analyzed using modal analysis in the frequency domain.Theoretical results for the propagating and reflected waveformsare obtained by applying the inverse discrete Fourier transform(IDFT) to the system responses. These responses are obtainedby applying the theory of multiconductor transmission linesto a dispersive database which has been computed using thespectral-domain approach (SDA). The response of a six-lineclosely coupled microstrip circuit terminated by the proposedtermination scheme is measured using the HP8510B networkanalyzer. The measured results show that the reflected signal isbelow -30 dB and the results are in good agreement with thetheoretical waveforms.