Analysis and design of a 400MHz-6GHz quadrature demodulator with high linearity

In the paper, a high linearity quadrature demodulator based on SiGe BiCMOS process is designed and implemented for 400MHz to 6GHz wireless communication application. The 3rd intermodulation cancellation technique is applied to improve linearity. A negative feedback structure is applied to Gilbert mixer to lower its input impedance and expand its bandwidth. Quadrature local oscillator signal generator is integrated, with excellent quadrature performance in the whole band. Measurement results show excellent performance in the frequency band of 400MHz to 6GHz.