  We present a technique for measuring microwave (MW) field based on Rabi
resonances induced by the interaction of atoms with a phase-modulated MW field.
A theoretical model of field measurement is used to calculate Rabi frequency.
Single-peak feature of the measurement model makes the technique a valuable
tool for simple and fast field measurement. As an example, we use the technique
to determine the MW field strength inside a Cs vapor cell in the X-band
rectangular cavity for applied power in the range of -21 dBm to 20 dBm. The
results show that this proposed technique is capable for detecting the field
over a broad dynamical range.
