  A microwave atomic clock scheme based on Rb and Cs atoms trapped in optical
lattice with magic wavelength for clock transition is proposed. The ac Stark
shift of clock transition due to trapping laser can be canceled at some
specific laser wavelengths. Comparing with in fountain clock, the cavity
related shifts, the collision shift, and the Doppler effect are eliminated or
suppressed dramatically in atomic clock when the magic optical lattice is
exploited. By carefully analyzing various sources of clock uncertainty, we
conclude that a microwave atomic clock with an accuracy of better than
$2\times10^{-17}$ is feasible, which is of the same accuracy as the expected
best optical atomic clock.
