A waveguide assembly system includes a fixed port, a sliding port, and a transmission path from the fixed port to the sliding port. The transmission path includes a waveguide assembly that includes a first minor face corresponding to the fixed port, a first major face that includes a recess extending from the first minor surface towards the fixed port. The waveguide assembly system also includes a port assembly with a first major surface disposed opposite to the first major surface of the waveguide assembly. The port assembly includes at least one port having a first opening on the first major surface of the port assembly and a second opening on a second major surface of the port assembly. The port assembly includes one or more stubs positioned to impede electromagnetic energy propagation beyond a specified distance within the port tab assembly.