Radio Frequency Circuit Design, 2nd Edition

APPENDIX G

Transformed Frequency-Domain Measurements Using SPICE

G.1 INTRODUCTION

Time-domain measurements taken on an automatic network analyzer can be easily replicated theoretically for dispersionless transmission lines using the SPICE time-domain program simulation. A technique is presented here that gives the type, value, and position of a measured discontinuity directly from time-domain measurements. Furthermore, the effect of multiple discontinuities can be replicated by SPICE.

Microwave impedance measurements have evolved from the slotted line to the computer-controlled automatic network analyzer. One of the major innovations of the network analyzer made possible by its broadband frequency capability was the simulation of time-domain measurements. Though fundamentally a frequency-domain machine, the network analyzer has been very useful in doing time-domain analysis of broadband circuits. This was demonstrated by the pioneering work of Hines and Stinehelfer [1]. Fundamentally, time-domain equipment such as the time-domain reflectometer have lagged because of the requirement for fast switching devices. However, that has not been true of the software side, as the widespread use of SPICE can readily attest. Here, it will be demonstrated how time-domain measurements on the network analyzer can be simulated using the transient analysis in SPICE.

There have been several studies that have shown how S parameters can be plotted using SPICE [2–4]. SPICE can be used to model physical ...