An Extension of Thru De-embedding Technique for Characterization of Asymmetrical and Differential Devices

Accurate RF characterization of on-chip or onboard devices often requires de-embedding to account for parallel and serial parasitics associated with bonding pads and interconnects. It is usually performed by well-known techniques such as e.g. Open-Short, Pad-Open-Short or Thru. However, these approaches or alternative techniques employing more standards assume a specific lumped-element model of bonding structures. This reduces de-embedding accuracy at higher frequencies. In this paper we analyze the Thru de-embedding technique.We show that under certain conditions de-embedding can be performed without modeling of the internal structure of the thru standard. The possibility to obtain the parameters of an error network by using a single test structure reduces significantly the costs of manufacturing standards and saves the measurement time. Further, we introduce an extension of the Thru technique. We show that at the expense of one more measurement it is possible to characterize the system without additional assumptions. The presented method can be applied e.g. for de-embedding of fixtures with different connectors on either side. We verify the methods by simulations performed using Sonnet EM field solver in the frequency range 1-40 GHz. Finally, we apply the Thru procedure for de-embedding of differential low-noise amplifier (LNA) at 18 GHz.