Abstract: A planar structure for a planar radio frequency filter is configured to block the transmission of electromagnetic waves in at least two independent radio frequency bands, the planar structure comprising a periodic array of multipole inclusions, wherein the periodic array of multipole inclusions comprises a plurality of primary multipole inclusions having a plurality of primary poles to generate a lower frequency resonance and a plurality of secondary poles to generate a higher frequency resonance, wherein the periodic array of multipoles are arranged with arms of the plurality of primary poles overlapping with and substantially parallel to adjacent arms of the plurality of primary poles of adjacent multipole inclusions. The array of multipole inclusions may include a plurality of secondary multipole inclusions located between the plurality of primary multipole inclusions to tune the higher frequency resonance.

Abstract: A planar radio frequency filter is described, comprising a frequency selective surface (FSS) applied to a substrate. The filter blocks the transmission of electromagnetic waves in at least two independent radio frequency bands. The FSS comprises a periodic array of multipole inclusions with skewed or forked poles to increase packing density. The inclusions comprise four or six primary poles to generate the lower frequency resonance and an additional four or six secondary poles to generate the higher frequency resonance. The secondary inclusions are located between the primary inclusions to tune the higher resonance frequency. The FSS incorporates overlapping parallel conducting segments that overlap to provide an inductive-capacitive path between adjacent inclusions.

Abstract: A planar radio frequency filter is described, comprising a frequency selective surface (FSS) applied to a substrate. The filter blocks the transmission of electromagnetic waves in at least two independent radio frequency bands. The FSS comprises a periodic array of multipole inclusions with skewed or forked poles to increase packing density. The inclusions comprise four or six primary poles to generate the lower frequency resonance and an additional four or six secondary poles to generate the higher frequency resonance. The secondary inclusions are located between the primary inclusions to tune the higher resonance frequency. The FSS incorporates overlapping parallel conducting segments that overlap to provide an inductive-capacitive path between adjacent inclusions.