On the use of sub-harmonic mixer in sliding-IF architecture for mm-Wave/THz transceivers

This paper discusses methods to implement a sub-THz transceiver for 300 GHz band with minimal LO frequency. An existing sub-harmonic mixer, used previously in direct conversion transceiver, is applied in a sliding-IF mixer architecture. Sub-harmonic mixer with sliding IF architecture is envisioned to further reduce the need of higher LO frequency for upconversion. In this aspect, two architectures are studied by spectral analysis and further verified through circuit simulator. The first has a problem with overlapping sidebands, making it unsuitable for non-symmetrical double sideband modulations. On the other hand, the second architecture manages to up-convert signals up to fo, using a single LO frequency of fo/3.