Analysis and Design of On-Chip RF Interconnect Line for Wideband True-Time Delay Line Application

This paper presents the analytical resistance-capacitance-inductance-conductance (RLCG) model of the on-chip interconnect line (IL) based on its structure, and the proposed model can be used to design IL and analyze the delay characteristics. Using electromagnetic (EM) simulation, the relations between the inductance, quality factor and the width, length of IL are obtained, which verifies the proposed RLCG model of IL. The delay model of IL is derived and verified with respect to the effects of the L and C by simulation, which can provide the benefit for the true-time delay line (TTDL) design using IL. This work proposes the experiments on the delay characteristics of 3-bit TTDL with IL based on 0.13 mu m SiGe BiCMOS technology. The group delay and transient delay of the TTDL are measured, which exhibits a maximal relative delay of 35 ps with an average of 5 ps delay resolution over a frequency range of 14-34 GHz. The results are consistent with the delay analysis based on the proposed IL model.