  Rydberg microwave (MW) sensors are superior to conventional antenna-based
techniques because of their wide operating frequency range and outstanding
potential sensitivity. Here, we demonstrate a Rydberg microwave receiver with a
high sensitivity of $62\,\mathrm{nV} \mathrm{cm}^{-1} \mathrm{Hz}^{-1/2}$ and
broad instantaneous bandwidth of up to $10.2\,\mathrm{MHz}$. Such excellent
performance was achieved by the amplification of one generated sideband wave
induced by the strong coupling field in the six-wave mixing process of the
Rydberg superheterodyne receiver, which was well predicted by our theory. Our
system, which possesses a uniquely enhanced instantaneous bandwidth and
high-sensitivity features that can be improved further, will promote the
application of Rydberg microwave electrometry in radar and communication.
