Development of Sub-Millimeter-Wave Power Amplifiers

In this paper, we present the framework for developing the first working power amplifiers at sub-millimeter-wave frequencies. The technology is made possible by an advanced InP HEMT transistor. A three-stage power amplifier is presented, which uses a binary combiner to realize a total output periphery of 80 mum and demonstrates 12-dB gain at 335 GHz, making, this the first demonstrated sub-millimeter-wave power amplifier. Measured saturated power of 2 mW at 330 GHz is also presented, which provides a transistor power benchmark of 25 mW/mm at 330 GHz. Finally, single-stage amplifier data with large periphery transistors are presented, which demonstrates 5-dB measured gain at 230 GHz and positive measured S₂₁ gain to ~300 GHz, demonstrating that power amplifiers using larger transistors are feasible at these frequencies as well.