Representing bias-network baseband characteristics when simulating intermodulation distortion

Abstract

We assess the expected impact that incorrect representation of the bias network will have on simulations of intermodulation distortion by quantifying the range of impedance values of several real baseband components, including bias tees, cables, and bias supply settings. We then introduce a table-based method to incorporate these elements in circuit simulations and verify its ability to improve prediction of intermodulation distortion. With this method, we are able to predict the third-order intermodulation distortion products to within 0.25 dB in the weakly nonlinear regime for a variety of baseband components. Use of the method enables improved model parameter extraction because only the device model itself remains in question if simulation and measurement results differ.