Failures in power-combining arrays

We derive a simple formula for the change in output when a device fails in a power-combining structure with identical matched devices. The loss is wri tten in terms of the scattering coefficient of the failed device and reflec tion coefficient of an input port in the combining network, We apply this f ormula to several power combiners, including arrays in free space and enclo sed waveguide structures. Our simulations indicate the output power degrade s gracefully as devices fail, which is in agreement with previously publish ed results.