A 192–229 GHz Frequency Tripler with 4.4 dBm Output Power Using Slotline-Based Drain Harmonic Shaping Technique in 40nm CMOS

A sub-terahertz frequency tripler using slotline-based drain harmonic shaping technique is presented in this work. The drain harmonic shaping technique optimizes harmonic utilization. It shapes the drain waveform by strengthening the nonlinearity at the drain and weakening the nonlinearity at source, thus improving the third harmonic output power. Instead of using center-tapped transformer, the excellent common-mode rejection of slotline is used to realize independent odd- and even-order harmonic tuning. A compact slotline-based output network is designed for simultaneous power combining and harmonic shaping. The proposed frequency tripler is implemented in 40nm bulk CMOS, achieves a saturate output power (P
sat
) of 4.4 dBm and a 3-dB bandwidth from 192 to 229 GHz, while featuring a compact core area of 0.09 mm
²
. To the best of our knowledge, the proposed tripler achieves the highest P
sat
among similar CMOS triplers and is comparable to doublers.