  One way to proof or exclude the existence of axion like particles is a
microwave light shining through the wall experiment. In this publication we
will emphasize on the engineering aspects of such a setup, currently under
development at CERN. One critical point, to achieve meaningful results, is the
electromagnetic shielding between axion-emitter and -receiver cavity, which
needs to be in the order of 300 dB to improve over existing experimental
bounds. The RF leakage or electromagnetic crosstalk between both cavities must
be well controlled and quantified during the complete duration of the
experiment. A very narrow band (in the 10^-6 Hz range) homodyne detection
method is used to reveal the axion signal from background thermal noise. The
current status of the experiment is presented.
