RF CMOS Tunable Gilbert Mixer with Wide Tuning Frequency and Controllable Bandwidth: Design Sythesis and Verification

The double-balanced Gilbert mixer is widely used in RF receivers. In general, it is desirable to design a wide tuning frequency Gilbert mixer for low power, high conversion gain, low noise figure, and good linearity, but they are not easy to attain simultaneously. Therefore, trade-offs always exist by tuning design parameters. To observe the trade-off relationship between each tunable parameter and to make a mixer achieve specified requirements easily (i.e., tuning frequency range, bandwidth, and power), an automated design synthesis and verification approach for Gilbert mixer is proposed. A wide tuning CMOS Gilbert mixer design synthesis while keeping the local oscillator frequency of 2 GHz is presented as an example. Designed in 180 nanometer CMOS process, the tunable Gilbert mixer achieves a tuning frequency span of 2 GHz (1.1 - 3.1 GHz), a controllable bandwidth of ~50 MHz, a high conversion gain (0.5 – 6.4 dB), a low noise figure (6.81 – 8.36 dB), and a power of 9 mW