  We report a broadband radio frequency (RF) channelizer with up to 92 channels
using a coherent microcomb source. A soliton crystal microcomb, generated by a
49 GHz micro-ring resonator (MRR), is used as a multi-wavelength source. Due to
its ultra-low comb spacing, up to 92 wavelengths are available in the C band,
yielding a broad operation bandwidth. Another high-Q MRR is employed as a
passive optical periodic filter to slice the RF spectrum with a high resolution
of 121.4 MHz. We experimentally achieve an instantaneous RF operation bandwidth
of 8.08 GHz and verify RF channelization up to 17.55 GHz via thermal tuning.
Our approach is a significant step towards the monolithically integrated
photonic RF receivers with reduced complexity, size, and unprecedented
performance, which is important for wide RF applications ranging from broadband
analog signal processing to digital-compatible signal detection.
