Disclosed here are apparatuses and methods including a waveguide having a length and a port. The waveguide is a split-block construction waveguide, which includes a seam between a first waveguide section and a second waveguide section. The first waveguide section and the second waveguide section form a waveguide cavity, and the seam corresponds to a low surface current location of a propagation mode of the waveguide. The apparatus also includes an antenna coupled to the port of the waveguide. The antenna is configured to (i) receive an electromagnetic signal and propagate the electromagnetic signal into the waveguide, and (ii) transmit a reflected electromagnetic signal from the waveguide. Additionally, the apparatus includes a reflecting component. The reflecting component is configured to provide a short in the waveguide along the length of the waveguide, and to move with a velocity to simulate a radar target having the velocity.