122 GHz transmitter using frequency doublers

In this work, a 122 GHz transmitter circuit using frequency doublers is realized in 0.13 μm SiGe:C BiCMOS technology with f_T/f_max of 250/315 GHz. Two versions of the frequency doubler based on the balanced topology with cascode transistor are implemented. In the basic version, the peak conversion gain was -9 dB with -6 dBm output power. In the improved version the peak conversion gain is improved to -6 dB with -3 dBm peak output power by using open stubs as second harmonic reflectors. A transmitter is realized by combining a VCO working from 59-62 GHz with the basic version of the doubler. The transmitter output power is from -3.5 to -5.5 dBm in the output frequency range of 118-122 GHz.