This research presents a novel cloaking technique which can render a metallic block invisible in a rectangular waveguide. The cloak consists of a stack of commonly used dielectric slabs. We perform the numerical simulation and observe the detour of the Poynting vector through the cloak. Furthermore, the experiment is implemented to measure the scattering parameters including the reflection and transmission coefficients. Great improvement in the transmission coefficient in a broad bandwidth after cloaking is demonstrated. The theory of mode conversion is utilized to explain the cloaking phenomenon.