Two-dimensionalmetallicphotoniccrystalslabswithsquarelatticeareproposedtobeusedforthedesignofwaveguidebandpassfiltersoperatinginmillimetertoterahertzregion.Filtercharacteristicsarestudiedwhenrodradiiandlatticeconstantsarechanged.Basedonthefrequencyscalingtechnique,aseriesofhigherfrequencyfiltershasbeendesigned.Byusinglaserdrillingandweldingprocessingtechniques,acompactwaveguidefilterembeddedinanEIA-WR10waveguidewithcentralfrequency145.5GHzand3-dBbandwidthof5.26GHzisfabricatedandmeasured.Themeasurementdataagreewellwiththesimulationprediction.