A G-Band Glass Interposer Technology for the Integration of an Amplified Noise Source based on SiGe BiCMOS 55-nm Technology

This paper introduces a substrate technology integrating SiGe BiCMOS based amplified noise source (NS) onto a glass interposer to reduce dielectric and transition losses. Previous work focused on characterizing the NS in two distinct configurations. On-wafer noise measurements revealed an excess noise ratio (ENRav) of 37 dB within 140-170GHz. However, the NS was packaged in a split-block with a WR5.1 flange termination for connection to passive probes, achieving an ENRav of 25 dB in G-band corresponding to 12 dB ENR reduction compared to on-wafer measurements. The paper proposes a third integration route using an ultra-thin glass interposer, employing femtosecond laser micro-machining for interconnect structuring. This enables the NS integration on the same substrate where the coplanar probing tips are manufactured, with the advantage of simplifying signal propagation, resulting in a tunable ENRav of 29 dB within 140-170GHz, with constant output impedance matching better than -12 dB over the G-band.