A 28 GHz High Slope Automatic Switching Power Detector System Using PMOS Current-Steering Variable Gain Amplifier and Schmitt Trigger

In this brief, we present a 28 GHz high slope automatic switching power detector system using a PMOS current-steering
VGA
and Schmitt trigger (
ST
) for 5G mobile communication. The forward
RF
path is composed of a four-stages variable gain amplifier and a buffer amplifier. The feedback path is composed of the power detector, two
ST
s, and an inverter to achieve an automatic gain switching mechanism. The input
RF
small-signal is amplified by the
RF
path and converted to dc voltage by power detector. By feedback path to switch to different gain states, it can extend the overall dynamic range with high slope and avoid the system from saturation. Based on ±1 dB log error, the measured minimum detectable power and dynamic range are −47.2 dBm and 41.5 dB at 28 GHz. The peak slope value are 61/59/67 mV/dB under three modes. Total
dc
power consumption is only 35 mW for 1.8 V supplied voltage. To our best knowledge, this power detector system is the first time using the automatic switching technique in the millimeter-wave band power detector. It has better minimum detectable power, dynamic range, and the highest slope among published power detector systems.