9 dB, which we hope to improve by reducing leakage
of LO power under the substrate into the signal port, and by improving
the match of the cold termination of the fourth port of the input
quadrature hybrid.
A. R. Kerr, S.-K. Pan [1], H. G. LeDuc, [2]
March 31, 1998
Keywords:
Separate waveguides for the signal and LO are connected via suspended
striplines to a 2 x 1 mm quartz substrate which contains all the RF
components of the sideband separating mixer: quadrature hybrid, LO
power splitter, two LO couplers, and two SIS mixers. These components
are realized in capacitively-loaded coplanar waveguide, which
minimizes stray coupling between adjacent components and coupling to
undesired modes in the thick quartz substrate. Over the 200-280 GHz
band, the mixer noise temperature was 50-150 K and the overall
receiver noise temperature was 60 - 200 K (both measured outside the
vacuum window). The sideband separation was 9 dB, which we hope to improve by reducing leakage
of LO power under the substrate into the signal port, and by improving
the match of the cold termination of the fourth port of the input
quadrature hybrid.
[1] NRAO-CV
[2] JPL
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