A filtering apparatus formed by a plurality of channel systems. Each of the channel systems include an inlet port formed on an inlet side of the plate; no more than one outlet port formed on an outlet side of the plate; and a channel formed in the plate, the channel coupled to the inlet port and to the outlet port, wherein the ratio of the product of the capture area of the inlet ports of a channel system with the first transmissivity associated with the inlet ports to the product of the capture area of the outlet ports of a channel system with the second transmissivity associated with the outlet ports is greater than one. The channel system is configured to interact with objects of interest on a scale which is smaller than a value several orders of magnitude larger than the mean free path of an object of interest. Some plate embodiments are configured to interact with particles, such as air molecules, water molecules, or aerosols. Other plate embodiments are configured to interact with waves or wavelike particles, such as electrons, photons, phonons or acoustic waves.