L-Band Diamond Amplifier with Multi-Finger Structure

This letter reports on an L-band diamond amplifier with a multi-finger structure. The 0.5 μm gate length two-dimensional hole gas diamond field-effect transistor, utilizing a multi-finger structure with a total gate width of 10 finger × 100 μm, aims to enhance high-frequency performance due to low gate resistance compared to a double-finger structure. It demonstrates large-signal operation over 2 GHz with a total gate width of more than 1 mm, marking a first in diamond field-effect transistor. The development of this amplifier was achieved using an atomic layer deposition two-dimensional hole gas diamond metal-oxide-semiconductor field-effect transistor, using a multi-finger structure with a total gate width of 10 finger × 50 μm, alongside printed circuit board and surface mount devices components. The resulting diamond amplifier exhibited linear gains of more than 7 dB and output power levels of 20.7 dBm, with maximum drain efficiency of 3.5 % achieved at 1.8 GHz, with drain voltage of -40 V. Among diamond amplifiers, this configuration demonstrated the highest output power performance.