Disclosed herein are methods and circuits that prevent energy that would produce a spurious resonance from lumped, distributed or waveguide circuit elements by using for example a low pass filter with a cut-off below the first spurious resonance frequency and bypassing the energy at frequencies at or above the first spurious resonance frequency through a secondary path. This secondary path is high pass in nature, with a cutoff substantially similar to the low pass filter. The two paths are combined at the common output, using a lowpass matching network.