An 18-20 GHz Subharmonic Satellite Down-Converter in 0.18μm SiGe Technology

This paper presents the design and implementation of a 18-20 GHz satellite down-converter receiver with a 10.5 GHz local oscillator. The circuit design is single-ended for minimal area and current consumption, and for compatibility with a GaAs low-noise pre-amplifier and a coaxial output transmission-line. The RF, LO and IF ports are ESD protected using on-chip diodes. The down- converter results in a measured gain of 35-40 dB, an output P_ldB of +2.4 dBm, and a noise figure of 4.8-9.8 dB for an input frequency of 18-20 GHz (IF of 3-1 GHz). The required LO power is 2-3 dBm. The measured IIP₃ is -36 dBm at 19 GHz. The chip consumes 31.5 mA from a 2.5 V supply, and 55% of the current is used for the output 50 Omega driver (17.3 mA). The chip is very small with a size of 1.1 times 0.7 mm including all pads and is built using a commercial 0.18-mum SiGe technology.