A Low Noise Receiver for M.M.D.S and L.M.D.S.

THOMSON-CSF Microélectronique developed a Q-band monolithic downconverter for millimeter-wave communication systems (MMDS, LMDS). This paper discusses two possible topologies for downconverter (including an image reject commonly mixer or an image reject filter), and the result obtained. The described downconverters integrate a 40-42 GHz LNA, a mixer, an hybrid local oscillator: a dielectric resonator oscillator (DRO) and an automatic gain control amplifier (AGC). The main features of this downconverter are a noise figure of less than 7 dB, a conversion gain of 36 dB and a frequency stability higher than ± 2.5 MHz over 85° C temperature range. The IF output is compatible with existing digital Set Top Boxes.