Abstract: A ceramic bandpass filter (10) that has transmission zeroes above the passband is accomplished without using the top patterning by a block structure that includes a localized mesa (26) formed at the top end of the block that provides increased capacitive coupling between the open circuits and the resonators (30, 32, and 34). This increased top end capacitance provided by the mesa (26) can provide high end or high side transmission zeroes to the characteristic transfer function of the filter.

Abstract: A dielectric resonator (400) is formed, according to the invention, from a block of dielectric material having top, bottom, and side surfaces. A protuberance (407) is formed on at least the top surface of the block. Further, a hole (405) is formed through the block, which hole extends substantially from the apex of the protuberance, through the block, to the bottom surface. The hole and protuberance combine to form a mesa structure (604, 704). The bottom surface, side surface, and an interior surface of the hole (405) are coated with a conductive layer. Further, a conductive coating is selectively disposed on the top surface of the block, which coating at least partially covers the mesa (604, 704). A dielectric block resonator (400, 500) is thereby formed whose resonant characteristics are at least partially determined by the physical dimensions of the mesa (604, 704).

Abstract: A dielectric block filter construction having resonating cavities formed therein to form one half wave-wavelength resonators thereby. The resonating cavities span opposing side surfaces of the dielectric block forming the dielectric block filter to define openings at the opposing side surfaces. Outer surfaces of the dielectric block, including the opposing side surfaces having the openings defined thereat, are coated with an electrically-conductive material except for portions of one side surface of the dielectric block about peripheral surfaces of input and output couplers formed on the one surface. Because the opposing outer surfaces are coated with the electrically-conductive material, the opposing outer surfaces of the dielectric block are self-shielding to prevent propagation of electromagnetic radiation through openings defined by the resonating cavities of the dielectric block.