A D-band SiGe Frequency Doubler with a Harmonic Reflector Embedded in a Triaxial Balun

This paper presents a SiGe push-push frequency doubler with a triaxial balun embedded harmonic reflector. An input triaxial balun is used to generate differential signals for the push-push core, while also providing a high quality 2nd harmonic reflector. Two frequency doublers were designed in a 90 nm SiGe BiCMOS platform, both with and without an output buffer. The buffer-less design achieves a record peak output power and efficiency of 9.4 dBm and 12.1% at 130 GHz, with a bandwidth of 128-140 GHz. The buffered design achieves a peak output power of 8.85 dBm and 8.8% efficiency, while operating over a wider bandwidth.