Surface mountable interdigital block filter having zero(s) in transfer function

Claim 1

A surface mountable interdigital block filter for filtering electrical signals, the block filter being substantially directly mountable on a conductive surface of a substrate, comprising: a substantially parallelepiped volume of dielectric material having at least a first and a second surface. substantially arranged to provide; at least three primary apertures extending coaxially from said first and Second surfaces and having conductive material disposed on an inner surface of said apertures to provide conductive resonator means, input and output secondary apertures extending coaxially from said first and second surfaces and having conductive material disposed on an inner surface of said secondary apertures to provide conductive resonator means, for at least facilitating external conductive connections and at least allowing desired provision and extraction of electrical signals, wherein the secondary apertures are operably coupled to the primary apertures and the apertures are arranged in an order of: a first primary aperture, the input secondary aperture, a second primary aperture, any primary apertures selected in addition to the three primary apertures, the output secondary aperture and a third primary aperture, a first conductive line is utilized for input into the input secondary aperture and a second conductive line is utilized for output from the output secondary aperture, wherein adjacent apertures are at least alternately connected and unconnected to a ground respectively along the first surface and along the second surface such than said conductive resonator means are interdigitated; and conductive material is disposed on at least Dart of the surfaces of the volume of dielectric material, substantially arranged to at least permit conductive surface mounting of the surface mountable interdigital block filter on the conductive surface of the substrate and to provide an electrical signal filter that provides for selectable frequency rejection response operation wherein the input and output secondary apertures are utilized, respectively, to radiate and receive signals to and from adjacent conductive interdigitated resonator(s) means, wherein said conductive interdigitated resonator means are constructed and arranged such that the block filter has at least a first pole and at least a first zero in its frequency transfer function provided by at least a first resonator that is utilized for zero(s) of a frequency transfer function, and wherein the input and output secondary apertures have a length that is different from the length of the primary apertures.