A microwave transmission assembly comprising a combiner comprising first and second input ports and internal and external output a ports; the combiner being adapted to transfer a signal received at microwave frequency f1 at the first input port to the external output port and signals received at other frequencies to the internal output port; the combiner being further adapted to transfer a signal at a microwave frequency f2 at the second input port to the external output port and signals received at the other frequencies to the internal output port; a resistive load connected to the internal output port; and, a power dependent reflective load connected in series with the resistive load, the power dependent reflective load comprising a reactive element, the reactive element comprising an inductive component and a capacitive component and being adapted to resonate at a load frequency; the impedance of the capacitive component being adapted to drop when the incident microwave power received by the power dependent reflective load exceeds a power limit so switching the power dependent load from a low impedance state to a high impedance state.