Techniques for wakeup in a low-power wireless device

A wakeup circuit for detecting a wakeup signal and operable in a low-power wireless device, comprising:

• a wakeup receiver configured to detect wakeup signals from radio frequency (RF) signals received at an antenna of the wireless device;
• an antenna tuner configured to tune a frequency of the antenna of the wireless device;
• and
• a controller configured to control the wakeup receiver to calibrate a sensitivity of the wakeup receiver by:
• initializing a wakeup sensitivity to a minimum wakeup sensitivity level of the wakeup receiver of;
• searching, by the wakeup circuit, for at least one known RF signal pattern;
• increasing the wakeup sensitivity level of the wakeup circuit when the at least one known RF signal pattern is not found;
• and
• setting the wakeup sensitivity to a wakeup sensitivity level at which the least one known RF signal pattern is received, wherein the controller is further configured to and to tune the frequency of the antenna to allow fast detection of a wakeup signal.