Mj. Wengler et al., 190-GHZ RADIATION FROM A QUASI-OPTICAL JOSEPHSON-JUNCTION ARRAY, IEEE transactions on microwave theory and techniques, 43(4), 1995, pp. 984-988
At 190 GHz, 0.36 mu W has been detected from an 11x58 array of niobium
Josephson junctions. The power is radiated directly into free space a
bove the surface of the two-dimensional array of junctions. Detection
is made by a commercial bolometer outside the array cryostat. The junc
tions in the array are closely spaced in the y-dimension, but spaced b
y more than one-half wavelength in the x-direction. This asymmetry res
ults in mutual phase-locking between adjacent junctions suitable for t
he production of y-polarized radiation, The resonance and asymmetry al
so result in a reasonable impedance match between the Josephson juncti
ons and the free-space radiation mode.