On-chip transformers: A circuit designer´s perspective on the loss and bandwidth

A generalized analysis of the loss and bandwidth of a transformer is presented from a circuit designer´s perspective. Effects, such as finite coil inductance, non-zero leakage inductance and coil resistances are analyzed and expressions for the achievable bandwidth and loss of the transformer, as derived from various circuit losses, are presented, followed by insights into the design and optimization of the transformer.