A Broadband 25 to 42 GHz SiGe Upconverter

A 0.13 SiGe upconverter circuit is presented that is suitable for use in broadband millimetre-wave transmitters and active phased arrays. The circuit accepts four differential IF inputs (I+, I−, Q+, Q−) in the frequency range of DC to 13 GHz. An off-chip X-band LO passes through an on-chip tripler before being used to drive the image rejection mixer. The resultant output may be placed anywhere in the frequency range of 25 to 42 GHz. When all four inputs are utilised the RF signals are combined passively at the mixer outputs to achieve an output referred P1dB compression point of +4.4 dBm without the need for additional amplifiers in the RF signal path. This paper highlights the measured bandwidth and single-tone compression characteristic of the circuit. Layout techniques are also briefly described.