Abstract: A filter (102) with an adjustable shunt zero. The filter (102) has a predetermined passband and stopband, and an input (104) and an output (106), and a variable reactance element (108) for adjusting the stopband frequency of maximum attenuation, also defined as a shunt zero, coupled to at least one of the input (104) and the output (106) of the filter (102), whereby the shunt zero is adjustable over a range of frequencies.

Abstract: A filter (102) with an adjustable bandwidth. The filter (102) has a predetermined passband and stopband, and an input (104), an output (106) and at least two resonator structures (116, 124), and a variable reactance element (108) for adjusting the bandwidth of the passband, coupled between the resonator structures (116, 124), whereby the frequency response is adjustable.

Abstract: Ceramic block filters can be constructed to have non-symmetrical, i.e. unequal, input and output impedances. These filters can be used to eliminate impedance matching networks in radio communications devices. These impedance matching networks (22, 14) are precluded when the input and/or output of a ceramic block filter (100) is controlled by appropriate selection of the physical parameters of the block to achieve a direct impedance match between an adjacent circuit element and subsequent signal processing stages in the device.

Abstract: A dielectric block filter assembly which is surface-mounted upon a circuit board. The circuit board includes an opening formed to extend therethrough, and parallel-extending projecting members, formed of a portion of the printed circuit board, which extend into the opening formed to extend through the circuit board. The dielectric block filter includes a bottom mounting surface having notches corresponding to the projecting members. Each notch includes a seating surface for seating against corresponding ones of the projecting members in mated engagement therewith.