Common-Base/Common-Gate Millimeter-Wave Power Detectors

Abstract

The principle of two common base/gate millimeter-wave power detectors is analyzed and validated by experimental results. The detectors have been designed for automatic level control and built-in-test millimeter-wave applications. Closed-form expressions are derived for the transfer characteristic as well as for the noise behavior of each detector. The circuits are fabricated in a BiCMOS 55 nm ( $ {f_{t}}/{f_{\max }} = $ 320 GHz/370 GHz) process from STMicroelectronics. Each detector occupies an area of 80 $\,\times\, $ 80 $\mu {\hbox{m}^{2}} $ and exhibits a relatively high input impedance at 60 GHz. Measurements show a detection dynamic range larger than 38 dB and a flat response over the 50–66 GHz bandwidth, for both detectors. Common-base detector shows a wider linear detection range than that of the common-gate one. Theoretical computation and computer simulation show that, for square-law detection, the minimum detectable input power (for $\hbox{SNR}= \hbox{10~dB}$ ) is around $ - \hbox{41~dBm} $ for the common-gate detector against $ - \hbox{50~dBm} $ for the common-base one. In their nominal bias conditions, the detectors' power consumption, under 1.2 V supply voltage, is 90 $\mu \hbox{W} $ for low input power and it increases to about 800 $ \mu \hbox{W} $ for 8.5 dBm input power. These performances are beyond the current state-of-the-art of millimeter-wave detectors.