Suppression of resonant modes in microwave packages

Undesirable resonant cavity modes of a metal package are shown to be damped effectively by placing a dielectric substrate coated with a resistive film in the cavity. Theoretical predictions are confirmed experimentally. The application of this technique to a hybrid phase shifter in which coupling to a resonant mode of the package degrades circuit performance is discussed. The undesirable interaction of the phase-shifting circuit and a resonant package mode is shown to be suppressed effectively by the introduction of the lossy film.<
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