G-band Frequency Converters in 130-nm InP DHBT Technology

This paper presents the design and characterisation of a two G-band (140 - 220 GHz) fundamental mixers. The mixers are implemented in a 130-nm indium phosphide (InP) double heterojunction bipolar transistor (DHBT) technology. First, a passive double balanced topology was investigated using a diode ring with balanced RF and LO ports. The mixer operates in both upconversion and downconversion modes. In order to reduce the power requirement on the local oscillator (LO) at G-band, the diodes were dc biased. Measurement results show that the mixer has an average conversion loss of 12.4 and 14 dB for upconversion and downconversion modes respectively and covers the frequency range extending from 180 to 194 GHz. The mixer exhibits an LO-RF isolation of 21 dB and requires an LO power of +2 dBm. An upconverting transconductance mixer topology was also investigated using the same technology. Measurement results show that the mixer has an average conversion gain of 1 dB over the frequency range of 171 to 220 GHz. The mixer operates as an upconverter and requires a low LO power of only -4 dBm.