PT Journal
AU Svechnikov, S
   Gol'tsman, G
   Voronov, B
   Yagoubov, P
   Cherednichenko, S
   Gershenzon, E
   Belitsky, V
   Ekstrom, H
   Kollberg, E
   Semenov, A
   Gousev, Y
   Renk, K
TI Spiral antenna NbN hot-electron bolometer mixer at submm frequencies
SO IEEE Trans. Appl. Supercond.
JI IEEE Trans. Appl. Supercond.
PY 1997
BP 3395
EP 3398
VL 7
IS 2
DI 10.1109/77.622105
DE NbN HEB mixers
AB We have studied the phonon-cooled hot-electron bolometer (HEB) as a quasioptical mixer based on a spiral antenna designed for the 0.3-1 THz frequency band and fabricated on sapphire and high resistivity silicon substrates. HEB devices were produced from superconducting 3.5-5 nm thick NbN films with a critical temperature 10-12 K and a critical current density of approximately 10/sup 7/ A/cm/sup 2/ at 4.2 K. For these devices we reached a DSB receiver noise temperature below 1500 K, a total conversion loss of L/sub t/=16 dB in the 500-700 GHz frequency range, an IF bandwidth of 3-4 GHz and an optimal LO absorbed power of /spl sime/4 /spl mu/W. We experimentally analyzed various contributions to the conversion loss and obtained an RF coupling factor of about 5 dB, internal mixer loss of 10 dB and IF mismatch of 1 dB.
ER