A WR4 Amplifier Module Chain With an 87 K Noise Temperature at 228 GHz

In this letter we report an ultra-low-noise amplifier module chain in the WR4 frequency range. The amplifier chips were fabricated in a 35 nm InP HEMT technology and packaged in waveguide housings utilizing quartz E-plane waveguide probes. When cryogenically cooled to 22 K and measured through a mylar vacuum window, the amplifier module chain achieves a receiver noise temperature of 87 K at 228 GHz and less than a 100 K noise temperature from 217 to 236 GHz. The LNA modules have 21–31 dB gain and the power dissipation is 12.4–15.8 mW. To the best of authors' knowledge, these are the lowest LNA noise temperatures at these frequencies reported to date.