An RF amplifier includes at least one harmonic trap filter with an array of shunt filter legs having a non-uniform resonance frequency distribution. The harmonic trap filter is configured to suppress frequencies in a suppression frequency range that includes harmonic frequencies of carrier frequencies in a range of carrier frequencies. Each of the shunt filter legs includes a capacitor and inductor coupled in series, and an intermediate node coupled between the capacitor and the inductor. Each intermediate node of the shunt filter leg is coupled to at least one other intermediate node of another shunt filter leg of the filter with a dampening resistor. Shunt filters at or near edges of the array are configured to have lower resonance frequencies than those at or near the center of the array to suppress excess current flow at edges of the RF amplifier.