A Novel Wideband <i>I</i> / <i>Q</i> Network With Multiple Phase Error Zeros for Millimeter-Wave High Image Rejection Mixer

A novel wideband <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$I/Q$ </tex-math></inline-formula> network with multiple phase error zeros (MPEZs) is proposed and adopted in a millimeter-wave (mmW) mixer design for high image rejection. The single-ended (SE) MPEZs <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$I/Q$ </tex-math></inline-formula> network combines topologies of low-pass network and bandpass network. Compared to the conventional <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$I/Q$ </tex-math></inline-formula> network, our design introduces an inductor <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$L_{C}$ </tex-math></inline-formula> in the bandpass network (I-path) to improve the bandwidth by generating a new phase error zero. Meanwhile, a capacitor <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C_{C}$ </tex-math></inline-formula> is inserted in the low- pass network (Q-path) to assist in optimizing the quadrature performance. Furthermore, a differential form of MPEZs <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$I/Q$ </tex-math></inline-formula> network is constructed and further improves the bandwidth and amplitude errors. In the differential structure, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$L_{C}$ </tex-math></inline-formula> can make the voltage gain of I- and Q-paths close to each other to reduce the amplitude error. <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C_{C}$ </tex-math></inline-formula> primarily affects the voltage gain of the Q-path but has little impact on the voltage gain of the I-path which can accommodate to slightly optimize the amplitude error. A mmW image rejection mixer (IRM) using the proposed differential <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$I/Q$ </tex-math></inline-formula> network was implemented by the TSMC 65 nm CMOS process. The mixer achieves a measured image-rejection ratio (IRR) higher than 40 dB within a bandwidth from 23.5 to 29.5 GHz (22.6%). It also shows a measured conversion gain (CG) of about 15.5 dB under 5 dBm local oscillator (LO) power, IP1 dB around -20 dBm, and the IIP3 from -14.2 to -12.8 dBm. The power consumption of the mixer with all buffers is 108 mW and the whole chip occupies 0.525 mm2.