3-D THz tomography with an InP HBT signal source and a SiGe HBT imaging receiver operating near 300 GHz

In this work, 3-D THz tomography was demonstrated with an InP HBT signal source and a SiGe HBT imaging receiver. The signal source employs a common-base differential pair for an LC cross-coupled topology. It shows an output power of 5.3 dBm at 305.8 GHz. The receiver, which serves as an imaging detector in this work, is composed of a fundamental mixer, a local oscillator, an IF detector, and an on-chip antenna. It exhibits a responsivity of 322 kV/W and NEP of 3.9 pW/Hz^1/2 at 300 GHz. A set of sinograms was acquired with an imaging setup employing the fabricated source and detector, and 3-D tomographic images were reconstructed based on the inverse filtered backprojection algorithm from the acquired sinograms.