Design and layout techniques for a mm‐wave body‐biased variable‐gain amplifier

A two‐stage mm‐wave variable‐gain amplifier is designed and implemented in a 65‐nm CMOS technology. A fully symmetric layout has been utilized to suppress the odd‐mode of propagation and increase the quality factor in co‐planar waveguide transmission lines. Moreover, a new design technique is proposed for implementing decoupling capacitors for mm‐wave frequencies. Body‐biasing technique is utilized to change the amplifier gain without significant change in the overall power consumption of the circuit. The measurement results show that the amplifier achieves a peak gain of 10 dB with a gain variation range of 25 dB while consuming 12 mW from a 1.2‐V supply. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:470–477, 2014.