A D-Band ×8 Frequency Multiplier With Harmonic Suppression Enhancements in SiGe BiCMOS

In this letter, a D-band frequency octupler ( $\times 8$ ) with high harmonic suppression is presented in a 0.13- $\mu $ m SiGe BiCMOS technology. To enhance the suppression of even harmonics among high harmonics, we have implemented and refined a waveform shaping technique that effectively elevates the second harmonic while suppressing the fourth, sixth, and higher even harmonics. Additionally, the transformer-based bandpass filters (BPFs) are integrated into the design of the $\times 8$ frequency multiplier to enhance the suppression of nontarget frequency signals without compromising power consumption. To validate our proposed concept, a D-band $\times 8$ frequency multiplier operating at 114.5–140 GHz is manufactured in a SiGe process. The circuit achieved an output power of −2.5 dBm with an input power of −2 dBm. Within the 3-dB bandwidth, the suppression of various harmonics exceeded 28 dBc and with the maximum suppression exceeding 38 dBc. The chip consumed 125 mW of power and occupied an area of $0.63\times 1.2$ mm2.