A ultra low-power highly-linear HITD based down-converter for K-band applications

In this paper a single balanced mixer, suitable for K band applications, is described. The prototype is realized using an InP process and it is based on heterojunction interband tunnel diodes (HITDs). The circuit, consisting of a pair of HITDs connected to a coplanar Lange coupler, is optimized by a proper diode scaling in the 19-26 GHz band, providing an IF ranging from zero up to 7 GHz. Measurements highlight a conversion loss ranging from 6 dB to 10 dB and an IIP3 of 8 dB in the desired band. Due to the diodes characteristic no DC supply is needed and the functionality is achieved with a LO power of -2 dBm. The results also show a good agreement between the experimental data and simulations.