A new equivalent circuit model for on-chip spiral transformers in CMOS RFICs

Abstract

A new compact model has been introduced to model on-chip spiral transformers. Unlike conventional models, which are often a compound of two spiral inductor models (i.e., the combination of two coupled … or 2-… sub-circuits), our new model only uses 12 elements to model the whole structure in the form of T topology. The new model is based on the physical meaning, and the process of model derivation is also presented. In addition, a simple parameter extraction procedure is proposed to get the elements' values without any fitting and optimization. In this procedure, a new method has been developed for the parameter extraction of the ladder circuit, which is commonly used to represent the skin effect. In order to verify the model's validity and accuracy, we have compared the simulated and measured self-inductance, quality factor, coupling coefficient and insertion loss, and an excellent agreement has been found over a broad frequency range up to the resonant frequency.

Integrated On-Chip Transformers: Recent Progress in the Design, Layout, Modeling and Fabrication

“…The accuracy of the model was verified by comparing the calculated and measured results, which only showed a slight difference of ~3.26% [44,45]. Similar methods of modeling and design of on-chip transformers have also been reported [15,46,47,48,49,50,51,52,53,54,55,56].…”

BiCMOS tunable bandpass filters with coupled‐inductor Q‐enhancement

“…However, RF filters have yet to be integrated and are currently implemented in various technologies. Integration of RF filters in silicon‐based ICs remains a challenge mainly due to the low quality factor (<20) of on‐chip inductors . The low quality factor of on‐chip inductors has the drawback of leading to high insertion loss in passive filter implantation.…”