One of the performance issues addressed by the waffle - iron filter is that in many waveguide filters the attenuation is dependent on the transmission modes of the incident signal .
Some filters can be quite bad at suppressing spurious modes which may be contained in this signal .
One of the performance issues addressed by the waffle - iron filter is that in many waveguide filters the attenuation is dependent on the transmission modes of the incident signal and some filters can be quite bad at suppressing spurious modes which may be contained in this signal .