High sensitivity millimeter-wave instrumentation

This paper describes a technique to increase the millimeterwave sensitivity of the popular 1740-1750 series SA (Scientific-Atlanta) receivers. The frequency coverage is conventionally extended with harmonic mixing techniques which reduce the sensitivity. Phase-locked circuitry was developed to allow the receiver to operate in a fundamental mixing mode which permits the measurement of millimeterwave antennas and radar targets with the same sensitivity achieved at microwave frequencies. At Ka-band a 30 dB enhancement in sensitivity results with the phase-locked circuitry compared with the conventional instrumentation.