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.