Abstract: An acoustic microwave filter comprises an input and an output, and a plurality of acoustic resonators coupled between the input and the output. The difference between the lowest resonant frequency and the highest resonant frequency of a plurality of resonators in the filter is at least 1.25 times the frequency separation of the resonator with the highest resonant frequency in the plurality of resonators.

Abstract: Methods for the design of microwave filters comprises comprising preferably the steps of inputting a first set of filter requirements, inputting a selection of circuit element types, inputting a selection of lossless circuit response variables, calculating normalized circuit element values based on the input parameters, and generate a first circuit, insert parasitic effects to the normalized circuit element values of the first circuit, and output at least the first circuit including the post-parasitic effect circuit values. Additional optional steps include: requirements to a normalized design space, performing an equivalent circuit transformation, unmapping the circuit to a real design space, performing a survey, and element removal optimization. Computer implement software, systems, and microwave filters designed in accordance with the method are included.

Abstract: A tunable RF filter comprises a signal transmission path having an input and output, a plurality of resonant elements disposed along the signal transmission path between the input and output, and a set of non-resonant elements coupling the resonant elements together to form a stop band having a plurality of transmission zeroes corresponding to respective frequencies of the resonant elements, and at least one sub-band between the transmission zeroes. The set of non-resonant elements comprises a first plurality of non-resonant elements respectively coupled in parallel with the resonant elements, and a second plurality of non-resonant elements respectively coupled in series with the resonant elements. The first plurality of non-resonant elements comprises at least one variable non-resonant element for selectively introducing at least one reflection zero within the stop band to create a pass band in one of the one sub-band(s) without varying any of the second plurality of non-resonant elements.

Abstract: An RF filter comprises a signal transmission path having an input and an output, a plurality of resonant elements disposed along the signal transmission path between the input and the output, and a plurality of non-resonant elements coupling the resonant elements together to form a stop band having a plurality of transmission zeroes corresponding to respective frequencies of the resonant elements, and at least one sub-band between the transmission zeroes. The non-resonant elements comprise at least one variable non-resonant element for selectively introducing at least one reflection zero within the stop band to create a pass band in a selected one of the sub-band(s). The RF filter further comprises an electrical controller configured for receiving an operating temperature, and adjusting the variable non-resonant element(s) based on the received operating temperature, thereby selectively moving the reflection zero(es) along the stop band to move the pass band within the selected sub-band.

Abstract: A method of designing a microwave filter using a computerized filter optimizer, comprises generating a filter circuit design in process (DIP) comprising a plurality of circuit elements having a plurality of resonant elements and one or more non-resonant elements, optimizing the DIP by inputting the DIP into the computerized filter optimizer, determining that one of the plurality of circuit elements in the DIP is insignificant, removing the one insignificant circuit element from the DIP, deriving a final filter circuit design from the DIP, and manufacturing the microwave filter based on the final filter circuit design.

Abstract: A method of designing an acoustic microwave filter comprises selecting a filter section based on frequency response requirements. The filter section includes an input, an output, and a plurality of circuit elements. The circuit elements have at least in-line acoustic resonators or in-shunt acoustic resonators. The method further comprises selecting a value for each circuit element, selecting a number of filter sections, and cascading the selected number of filter sections to create a cascaded filter circuit design, such that at least one pair of immediately adjacent filter sections are connected to each other via their inputs or their outputs. The method further comprises adding parasitic effects to the cascaded filter circuit design to create a pre-optimized filter circuit design, optimizing the pre-optimized filter circuit design to create a final filter circuit design, and constructing the acoustic microwave filter based on the final filter circuit design.