Metamorphic HEMT amplifier circuits for use in a high resolution 210 GHz radar

In this paper, we present the development of a W-band power amplifier (PA) circuit and a G-band low-noise amplifier (LNA) MMIC for use in a high-resolution radar system operating at 210 GHz. The power amplifier circuit has been realized using a 0.1 µm InAlAs/InGaAs based depletion-type metamorphic high electron mobility transistor (MHEMT) technology in combination with grounded coplanar circuit topology and cascade transistors, thus leading to a small-signal gain of 12 dB and a saturated output power of 20.5 dBm at 105 GHz. The low-noise amplifier MMIC was fabricated using an advanced 0.05 µm MHEMT technology and achieved a small-signal gain of more than 16 dB over the frequency band from 180 to 220 GHz together with a state-of-the-art room temperature noise figure of only 4.8 dB. Both amplifier circuits were successfully packaged into millimeter-wave waveguide modules and used to realize a 210 GHz radar, which delivers an instantaneous bandwidth of 8 GHz and an outstanding spatial resolution of 1.8 cm.