Programmable electroacoustic filter apparatus and method for its manufacture

An acoustically coupled frequency selective radio frequency (RF) device, comprising:

• a piezoelectric substrate;
• a plurality of electrodes overlying the substrate;
• a pair of RF input terminals, at least one of which is electrically connected to at east one of said electrodes;
• and
• a pair of output RF terminals, at least one of which is electrically connected to at least one other of said electrodes;
• wherein at least one of said electrodes is electromechanically reconfigurable between a state in which it is closer to a face of the piezoelectric substrate and at least one state in which it is farther from the face of the piezoelectric substrate, and wherein:
• the plurality of electrodes includes an input array of electrodes electrically connected to the input RE terminal pair, an output array of electrodes electrically connected to the output RE terminal pair, and a pair of end electrode arrays configurable as acoustic reflectors, wherein the respective end electrode arrays are situated such that, when configured as acoustic reflectors, they form the end mirrors of an acoustic cavity that contains the input and output arrays.

An acoustically coupled frequency selective radio frequency (RF) device, comprising:

• a piezoelectric substrate;
• a plurality of electrodes overlying the substrate;
• a pair of RF input terminals, at least one of which is electrically connected to at least one of said electrodes;
• and
• a pair of output RE terminals, at least one of which is electrically connected to at least one other of said electrodes;
• wherein at least one of said electrodes is electromechanically reconfigurable between a state in which it is closer to a face of the piezoelectric substrate such that the electrode is piezoelectrically coupled to the piezoelectric substrate, and at least one state in which the electrode is farther from the face of the piezoelectric substrate, and wherein:
• an acoustic propagation axis is defined on the piezoelectric substrate;
• the electrodes are elongate in a direction parallel to the face of the substrate and perpendicular to the propagation axis;
• the plurality of electrodes includes at least one array of individually selectable electrodes that are collectively electrically connected to a terminal;
• the terminal is switchable between an RF signal connection and a ground connection;
• and
• at least one said array is reconfigurable by changing the selection of electrodes to be placed in the state that is closer to the substrate face.

A method for controlling an acoustically coupled frequency selective radio frequency (RF) device of the kind that comprises a piezoelectric substrate and a plurality of electrodes overlying the substrate, comprising actuating one or more capacitive switches such that one or more of the electrodes are reversibly raised from a position on or near a face of the piezoelectric substrate or lowered into such a position, wherein:

• at least some of the electrodes are disposed in an array;
• the actuating step is carried out so as to configure the array in a repeating pattern of unit cells;
• and
• the actuating step is further carried out such that each unit cell is a combination of raised electrodes and lowered electrodes.

A method for controlling an acoustically coupled frequency selective radio frequency (RF) device of the kind that comprises a piezoelectric substrate and a plurality of electrodes overlying the substrate, comprising actuating one or more capacitive switches such that one or more of the electrodes are reversibly raised from a position on or near a face of the piezoelectric substrate or lowered into such a position, wherein:

• at least some of the electrodes are respectively disposed in one or more arrays;
• the actuating step is carried out so as to configure each array in a repeating pattern of unit cells;
• the actuating step is further carried out such that each unit cell is a combination of raised electrodes and lowered electrodes;
• and
• the method further comprises switching at least one said array between a state in which it is connected to a radiofrequency (RF) input or output and a state in which it is connected to ground.