SiGe HBT amplifiers with high image rejection for quasi-millimeter-wave frequency range

24-GHz band amplifiers with a high image-rejection function have been designed and characterized using a 0.18-µm SiGe BiCMOS technology. To achieve a higher image-rejection ratio (IRR) in the quasi-millimeter-wave frequency region, an amplifier configuration with a notch-filter type feedback circuit has been proposed. A low noise amplifier (LNA) and a driver amplifier (DA) were developed to eliminate the image-frequency signal for super-heterodyne transceivers. The LNA obtained a 16.5-dB gain, 5.9-dB NF at 24 GHz and a more than 40-dB IRR at a frequency of 18.5 GHz. The power consumption was 8.4 mW with a 1.4-V power supply. The DA also achieved a 6.5-dB gain at 24 GHz and a 40-dB IRR at 16 GHz. Moreover, large-signal characteristics such as an OP1dB of +1.4 dBm and an OIP3 of +15 dBm were obtained for a power consumption of 15 mW with a 1.5-V power supply. The large-signal capability of the IRR was also experimentally confirmed.