Theory and Design of $N$-Push BJT Clamping Harmonic Generator for Silicon Terahertz ICs

We present a
$N$
-push BJT clamping harmonic generator and an optimal operation condition is derived to maximize the desired
$N ^{th}$
harmonic component. Under the hard switching condition, harmonic currents are calculated from time domain waveform generated from a simplified BJT model. Output waveform and the harmonic currents match well with Harmonic Balance (HB) simulation. For verification, measurements from a 380 GHz quadrupler with the on-chip patch antenna implemented in 0.13
$\mu{\rm m}$
SiGe BiCMOS are presented. Optimal biasing point for maximum EIRP corresponds well with the calculated value.