An embodiment of the present invention provides an apparatus, comprising a filter; and a matching network coupled to the filter, the matching network including a plurality of voltage tunable dielectric varactors. Specifically, the crystalline calcium carbonate has a substantially rhombohedral crystal structure with 1,0-1,1 crystallographic indices. In some embodiments, after the polymerization process is partially complete, a solvent rinse is performed, or fresh polymer precursor introduced into the microchannel. A first register holds control data of the switching circuit. The teeth are oriented to allow movement of the male pipe in a first direction relative to the female bell end opening during assembly, but to resist movement in a opposite direction after the pipe joint has been assembled.