A CMOS Adaptive Cumulative Probability Density Normalization Indicator for Broadband Millimeter-Wave Magnitude Modulation Signal

This letter presents a low-power, broadband Ka-band radio frequency (RF) self-adjustment magnitude normalization indicator circuit, which is designed based on cumulative probability density (PD) distribution principles and fabricated in TSMC 65-nm CMOS technology. Compared with conventional approaches, this fully integrated solution eliminates the need for analog-to-digital converters (ADCs). The PD statistical circuit converts PD into an equivalent voltage (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{\text {STA}}$</tex-math> </inline-formula>), which is compared with a preset reference value <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{\text {REF}}$</tex-math> </inline-formula> to dynamically adjust the normalization voltage (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{\text {PD}}$</tex-math> </inline-formula>). Within the Ka-band frequency range (26.5–40 GHz), for input power levels from −15 to 5 dBm and signal bandwidths up to 400 MHz, the circuit achieves less than 7.8% deviation between the normalization voltage and its ideal value. The indicator circuit consumes only 9.5 mW at a 1-V supply voltage, significantly reducing system complexity and power consumption.