ESD mm-Wave-Circuit Protection: 3-dB Couplers

Abstract

This paper presents an innovative architecture for the implementation of an Electrostatic Discharge (ESD) protection for mm-wave devices. The proposed architecture is based on the use of 3-dB couplers, whose coupled outputs have been shorted to the ground node. In order to reduce the physical dimensions of the 3-dB coupler and to reach the high coupling required for this application, the Coupled Slow-wave CoPlanar Waveguides (CS-CPW) architecture was favored. The demonstrator of the proposed system was fabricated in the ST Microelectronics 55-nm BiCMOS technology, demonstrating a return loss greater than 10 dB across the 50 to 160 GHz frequency range, an attenuation greater than 18 dB below 5 GHz and a minimum insertion loss at 90 GHz of 0.55 dB. To prove the performance of the proposed solution, HBM and CDM events were simulated at the input of the 3-dB coupler, showing that the proposed architecture effectively protects against these events while minimally impacting the RF path.