Demonstration of a Drain-Bar-Based Supply Concept for H-Band High Power Amplifiers

This paper reports for the first time the demonstration of a drain-bar concept for high power amplifiers operating in H-band (220–325 GHz). The presented design is based on so-called power-cells, which are four-finger-transistors consisting out of two distinct two-finger devices embedded in a passive structure. The novelty is that the presented layout of the four-finger device is adapted for the drain-bar concept. This novel drain-bar powercell can be stacked to build the required parallelization. Stacking of the power-cells forms the drain-bar, which supplies all drains and suppresses odd-mode oscillations. The presented amplifier is fabricated in a 35 nm InGaAs mHEMT technology and operates at a center frequency of 248 GHz with a 3 dB bandwidth of 30 GHz. An
$\mathbf{OP}_{\mathbf{1}\mathbf{dB}}$
of 3 dBm is measured.