CAD Modeling of mm-Wave Circuits Incorporating Avalanche Noise Diodes

This paper proposes, for the first time, a completely stand alone avalanche diode model based on a C++ code. The code, implemented within the Advanced Design Systems (ADS) environment, describes the diode behavior in terms of impedance and noise, by means of equations for which no more look-up tables are required. This also contains a modification with respect to the original Gilden and Hines model. Although completely general, the model is presented and discussed using a 20 square microns p-i-n diode, previously published by the authors. In order to validate the model in complex systems, the aforementioned diode is placed within two circuits of practical interest that have been designed using a commercial 130-nm SiGe BiCMOS technology. In particular: (a) the diode is connected with a wide-band bias tee and an 6-dB attenuator, in order to create a Noise Source (NS) system block, and (b) the same NS structure is connected with an Low-Noise Amplifier (LNA). The two prototypes have been fabricated and experimentally characterized in terms of impedance and Excess Noise Ratio (ENR). Finally the experimental results have been compared with model simulations. In the frequency range from DC to 26.5 GHz the agreement between simulated ENR and experiments is within 1.4 dB for the prototype (a) and 1.9 dB for the prototype (b). The obtained results enable the adoption of avalanche noise diodes in Computer Aided Design (CAD) tools, for the prediction of integrated circuits performances, and confirms the reliability of the developed model.