28 GHz active I/Q mixer with integrated QVCO in SiGe bipolar technology

An active I/Q mixer with integrated quadrature oscillator (QVCO) is discussed. It operates at LMDS frequencies at 28 GHz and converts the input signal to two output signals which differ in phase by 90 degree. This is achieved with an integrated QVCO. The I/Q mixer has a gain of 3 dB, a double-sideband noise figure of 16 dB and a 1 dB compression point referred to the input of -8 dBm. The circuit is realized in a pre-production 0.4 µm SiGe bipolar technology.