High IIP2 CMOS doubly balanced quadrature sub-harmonic mixer for 5 GHz direct conversion receiver
by Parag Upadhyaya, M.S.
Washington State University
Chair: Deukhyoun Heo
This thesis presents a new low power and high IIP2 0.25-µm CMOS doubly balanced
sub-harmonic mixer for 5 GHz Industrial Scientific Medical (ISM) band direct conversion - zero
IF receiver. Using a ½X LO frequency generation scheme the sub-harmonic mixer overcomes
LO self-mixing problem common in conventional direct conversion receivers (DCR).
Measurement shows the sub-harmonic mixer is able to achieve voltage conversion gain of 8.2
dB, input compression P1dB of –8 dBm, IIP3 of –2.5 dBm and IIP2 of 36 dBm while consuming
only 1.35 mA of DC current. Measured results correlate well with simulated results where the
mixer is able to achieve high IIP2 of 55.3 dBm, IIP3 of –6.5 dBm, P1dB of –12 dBm and voltage
conversion gain of 8 dB including 1% gm mismatch, 0.5% load mismatch and 2º LO phase error.
The mixer takes up less than 1mm2 of silicon real estate including test die pads.
This work also gives an overview of direct conversion RF transceiver architecture and its
design challenges and potential solutions for addressing 1/f noise, DC offset, 3rd order
intermodulation products and more importantly 2nd order intermodulation in the mixer. Two
novel CMOS doubly balanced quadrature sub-harmonic mixer architectures, which have high
immunity to 2nd order intermodulation products and achieves high IIP2 needed for DCR
applications, are presented. While sub-harmonic are generally associated with microwave
frequency design in 10s and 100s of gigahertz, a novel topology shows its viability for 5 GHz
ISM band applications, which includes IEEE 802.11a and Hiperlan2 wireless LAN standards in
the US and Europe, respectively. The design emphasizes trifecta of low power, low voltage, and
low cost sub-harmonic mixer design that can be applied to CMOS and SiGe technologies. The
mixer theory and design methodology presented can be also be followed as a design guide for
developing high performance mixer circuits for many applications including superheterodyne
transceivers and are not just limited to homodyne transceivers.
School:Washington State University
School Location:USA - Washington
Source Type:Master's Thesis
Keywords:metal oxide semiconductors complementary
Date of Publication: