Compact Lightweight Wideband Multi-channel Millimetre-Wave Self-sufficient Down Converter

Design of a compact, lightweight, wideband multi-channel, self-sufficient, phased matched millimetre-wave down converter has been discussed in this article. Here single stage down conversion has been use to down convert millimetre wave signals to S band IF signal with the help of Ku band LO signals. Frequency planning is done carefully to avoid in-band unwanted spurs. Low loss sharp rejection narrow band pass filter is used to get excellent image rejection characteristics. Each down converted IF signal is further converted to differential status signals. These status signals are used to control the operation of the down converter itself. Excellent in-band and out of band harmonics/ spur rejection has been targeted over ultra wideband frequencies. 2dB±1.5dB gain variation, >60dB harmonic/spurious rejection (over DC-40GHz) with >56dBc (min) image rejections have been achieved in the developed prototypes over −25°C to +55°C and 3 axis (X-Y-Z) random vibrations to establish the design concept.