Abstract: A leadless ceramic chip carrier useful in surface mounting of SAW devices includes electrically conductive vias and metalization between input and output bond pads for improved crosstalk suppression between input and output device connections. A protrusion extending from a top layer of a multilayer ceramic carrier provides additional electrical contact to a package seal brazed thereto. The vias are positioned between input and output bond pads and connect the metalized protrusion to package ground pads through contact with multiple metalized layers of the package for enhancing the electrical connection between the package Kovar seal ring and customer accessed ground pads. For further suppression of crosstalk, bond pads within the package for connection to the SAW device are spaced at a greater distance from each other than their corresponding pads on the package bottom surface thus maintaining an optimum spacing for package connection to printed circuit board pads for minimizing thermal mismatch effects.

Abstract: A lanthanum gallium tantalate single crystal substrate, referred to as langatate, has a prescribed range of Euler angles for substrate and crystal orientation for improving signal processing for a surface acoustic wave (SAW) device. When a voltage is applied to an input interdigital transducer (IDT) of the SAW device, a surface acoustic wave is generated in the langatate piezoelectric substrate. The surface acoustic wave propagates in a direction generally perpendicular to electrodes of the IDT. The langatate crystal cut and wave propagation directions are defined which reduce insertion loss and frequency response distortion due to SAW transduction, diffraction, and beam steering, while achieving improved temperature stability SAW device as compared to other commonly used crystal substrates. A low power flow angle and reduced level of diffraction is also achieved.

Abstract: A lanthanum gallium silicate single crystal substrate, referred to as langasite, has a prescribed range of Euler angles for substrate and crystal orientation for improving signal processing for a surface acoustic wave (SAW) device. When a voltage is applied to an input interdigital transducer (IDT) of the SAW device, a surface acoustic wave is generated in the langasite piezoelectric substrate. The surface acoustic wave propagates in a direction generally perpendicular to electrodes of the IDT. The langasite crystal cut and wave propagation directions are defined which reduce insertion loss due to SAW transduction, diffraction, and beam steering. As a result, temperature stability for the SAW device is improved. A low power flow angle and reduced level of diffraction is also achieved.

Abstract: A lanthanum gallium niobate single crystal substrate, referred to as langanite, has a prescribed range of Euler angles for substrate and crystal orientation for improving signal processing for a surface acoustic wave (SAW) device. When a voltage is applied to an input interdigital transducer (IDT) of the SAW device, a surface acoustic wave is generated in the langanite piezoelectric substrate. The surface acoustic wave propagates in a direction generally perpendicular to electrodes of the IDT. The langanite crystal cut and wave propagation directions are defined which reduce insertion loss and frequency response distortion due to SAW transduction, diffraction, and beam steering, while achieving improved temperature stability SAW device as compared to other commonly used crystal substrates. A low power flow angle and reduced level of diffraction is also achieved.

Abstract: A quartz single crystal substrate (12), includes a prescribed range of Euler angles for substrate and crystal orientation which improves signal processing for surface acoustic wave (SAW) devices (10). When a voltage is applied to an input inter digital transducer (IDT) (16) of the SAW device (10), a surface acoustic wave is generated in the quartz substrate (12). The surface acoustic wave propagates in a direction generally perpendicular to electrodes (20) of the IDT (16). The quartz crystal cut and wave propagation directions are defined to reduce the adverse effects of diffraction on SAW devices (10). As a result, frequency response distortions and insertion loss increases due to diffraction are reduced while maintaining good temperature stability and a low power flow angle.

Abstract: A surface mounting stress relief system for mounting a surface mount package such as a leadless ceramic chip carrier on a printed circuit board includes a printed circuit board having a top layer attached to a bottom layer. The top layer includes cavities for exposing top surface portion of the bottom layer which carry a plurality of solder pads. The surface mount package is positioned on the printed circuit board for placing the package bottom surface on a top surface of the printed circuit board between the cavities while positioning package contact pads in spaced relation above corresponding preselected solder pads. A solder column extends between each of the plurality of corresponding solder pads and the selected contact pads for providing an electrical connection.

Abstract: A lanthanum gallium silicate single crystal substrate, referred to as langasite, has a prescribed range of Euler angles for substrate and crystal orientation for improving signal processing for a surface acoustic wave (SAW) device. When a voltage is applied to an input interdigital transducer (IDT) of the SAW device, a surface acoustic wave is generated in the langasite piezoelectric substrate. The surface acoustic wave propagates in a direction generally perpendicular to electrodes of the IDT. The langasite crystal cut and wave propagation directions are defined which reduce insertion loss due to SAW transduction, diffraction, and beam steering. As a result, temperature stability for the SAW device is improved. A low power flow angle and reduced level of diffraction is also achieved.

Abstract: A lanthanum gallium niobate single crystal substrate, referred to as langanite, has a prescribed range of Euler angles for substrate and crystal orientation for improving signal processing for a surface acoustic wave (SAW) device. When a voltage is applied to an input interdigital transducer (IDT) of the SAW device, a surface acoustic wave is generated in the langanite piezoelectric substrate. The surface acoustic wave propagates in a direction generally perpendicular to electrodes of the IDT. The langanite crystal cut and wave propagation directions are defined which reduce insertion loss and frequency response distortion due to SAW transduction, diffraction, and beam steering, while achieving improved temperature stability SAW device as compared to other commonly used crystal substrates. A low power flow angle and reduced level of diffraction is also achieved.

Abstract: A seam welder for sealing a cover of a surface mount package to its carrier includes a table for receiving a fixture which itself carried surface mount packages to be welded for sealing an electronic component therein. Electrical current to welding electrodes is controlled for resistance welding the cover to the carrier. Electrode temperature and table temperature and monitored. Heat exchangers including a reservoir and heat transfer fluid interface with the electrodes and the table for controlling their respective temperatures and thus the temperature of the fixture and package during the welding of the cover to the carrier.

Abstract: A leadless ceramic chip carrier useful in surface mounting of SAW devices includes electrically conductive vias and metalization between input and output bond pads for improved crosstalk suppression between input and output device connections. A protrusion extending from a top layer of a multilayer ceramic carrier provides additional electrical contact to a package seal brazed thereto. The vias are positioned between input and output bond pads and connect the metalized protrusion to package ground pads through contact with multiple metalized layers of the package for enhancing the electrical connection between the package Kovar seal ring and customer accessed ground pads. For further suppression of crosstalk, bond pads within the package for connection to the SAW device are spaced at a greater distance from each other than their corresponding pads on the package bottom surface thus maintaining an optimum spacing for package connection to printed circuit board pads for minimizing thermal mismatch effects.

Abstract: A sensing apparatus includes a sensor package for generating an output signal responsive to a sensed quantity. The sensor package includes a surface acoustic wave (SAW) sensor and driver driver circuit mounted within a common package to facilitate connection to the associated processing apparatus. More particularly, the SAW sensor has a delay related to a sensed quantity, but generates undesirable reflections responsive to pulses propagating therethrough. The driver is controllable for delivering a series of pulses to the SAW sensor with each pulse having a random phase to thereby reduce effects of the undesired reflections of the SAW sensor. The sensor package also preferably includes connectors carried by the package for facilitating connection of the sensor package to the associated processing apparatus to permit susbstitution or replacement, for example.

Abstract: A dual track, low signal loss surface acoustic wave filter includes tapered transducers and tapered reflectors within an axis of propagation for each track to achieve an improved pass band response associated with tapered transducers. The bandwidth of the filter is achieved by adjusting the taper of periodicity normal to the propagation axis. Each track includes reflector gratings mounted on the filter substrate for reflecting a surface acoustic wave propagating from a transducer mounted within each track back to the transducer. Input and output transducers are positioned between the reflectors within each track for providing a direct surface acoustic wave propagation path within the track between the transducers. Alternate parallel tracks have the reflector with an input transducer, and a reflector with an output transducers mounted in an offset alignment with a corresponding adjacent track reflector and transducer for constructively adding surface acoustic wave signals detected within the adjacent track.

Abstract: Selected transducer geometries including unbalanced split electrode and three electrode per wavelength structures are employed for use in wide band tapered SAW devices. Combining geometries useful in narrow bandwidth SAW filters for canceling reflected waves leading to triple transit interference, and electrode tapering useful in wide bandwidth SAW filters for permitting transduction of a wide range of surface acoustic wavelengths has the unexpected result of significantly reducing insertion loss and improving triple transit suppression over wider bandwidths than can be achieved with SPUDT designs on non-tapered devices. The interdigitized electrode fingers of opposing bus bars in the transducer have a tapered alignment wherein a period of electrode finger portions along an acoustic wave propagation axis decreases along a transducer dimension.

Abstract: Surface acoustic wave (SAW) filter performance is enhanced using series-block weighting and line-width weighting combined for providing a transducer having a finely adjusted uniform weighting across the beam profile. Such a transducer permits practical transducer pairing within a surface acoustic wave filter, as well as use with transducers requiring uniform weighting, such as transducers employing apodized weighting. A three electrode per wavelength transducer electrode finger geometry includes line-width weighting for providing a fine weighting control to complement the inherently coarse weighting control of the series-block weighted transducer. Selected transducer geometries including three electrode per wavelength structures are employed for use in wide band tapered electrode finger SAW devices.

Abstract: A sensing apparatus includes a pulse recirculating circuit operatively connected to at least one ultrasonic delay sensor or other device for recirculating pulses therethrough, and a measurement difference output circuit for generating an output signal based upon a difference between first and second measurements of the at least one ultrasonic delay sensor. The pulse recirculating circuit preferably comprises a pulse generator for generating a series of input pulses to the ultrasonic delay sensor, and a pulse detector for detecting a series of output pulses after propagation through the ultrasonic delay sensor. Moreover, the measurement difference output circuit preferably includes an up-down counter for counting pulses during the first measurement in one direction and for counting pulses during the second measurement in an opposite direction. Accordingly, the remaining counter contents represent a difference in delay between the first and second measurements.

Abstract: An embodiment of a sensing apparatus includes an ultrasonic delay sensor having a delay related to the sensed quantity; and a time domain analysis circuit for recirculating pulses through the ultrasonic delay sensor or device and for generating the output signal related to the sensed quantity. In particular, the time domain analysis circuit may include a pulse generator for generating a series of input pulses to the ultrasonic delay sensor; a pulse detector for detecting a series of output pulses after propagation through the ultrasonic delay sensor; and a pulse recirculating circuit for causing the pulse generator to generate the series of input pulses based upon respective previously detected output pulses from the pulse detector. The apparatus also preferably includes circuits for suppressing the undesirable reflections generated by the ultrasonic delay sensor.

Abstract: An apparatus includes an ultrasonic delay sensor or device having a delay related to the sensed quantity; a pulse recirculating circuit for recirculating pulses through the ultrasonic delay sensor for generating a pulse repetition signal having a frequency related to delay of the ultrasonic delay sensor; and an output circuit for generating an output signal related to delay in the ultrasonic delay sensor based upon a difference in phase velocity between the pulse repetition signal and a time base signal. The output circuit preferably includes a first multiplier for multiplying the pulse repetition signal by a first number, and a second multiplier for multiplying the time base signal by a second number to have a frequency substantially the same as the multiplied pulse repetition signal. The effects of undesired reflections in the ultrasonic delay device may also be reduced or suppressed. Method aspects of the invention are also disclosed.

Abstract: A device and method for mounting a surface mount package onto a printed circuit board includes inserting a pin through a printed circuit board feedthrough for providing movement of the pin within the feedthrough. One end of the pin is soldered to conductive surfaces on the bottom side of the printed circuit board while the other end of the pin id soldered to a surface mount package pad. The package is mounted in a spaced relation with a printed circuit board top surface. The pin is soldered to the board conductive surface using a high temperature solder for forming a solder joint which remains solid during subsequent soldering using a low temperature solder such as a lead tin solder type. The pin is then soldered to the pad of the surface mount package using the low temperature lead tin solder for forming a solder joint between the pad and pin.

Abstract: A hidden lead package device is configured to be placed between a leadless component such as a surface mount package (SMP) used to house a SAW device and a standard printed circuit board configured for solder joints in a leadless contact with the printed circuit board. The hidden lead device is made using materials having similar characteristic thermal expansion properties as that of the SMP and printed circuit board pads to which the hidden lead is affixed. The hidden lead extends across the underside of the SMP along the PCB surface. One end of the lead is brazed to an SMP pad and the opposite end is soldered to a communicating PCB pad. The brazing temperature is higher than the reflow temperature for the solder. The hidden lead device causes the relative movement between the leadless carrier and the printed circuit board to occur along a length of the hidden lead and thus minimizes tensional or compressive forces to the solder joints.

Abstract: An interface printed circuit board is configured to be placed between a leadless component such as a surface mount package used to house a SAW device and a standard printed circuit board configured for solder joints in a leadless contact with the printed circuit board. The interface device is made using materials having similar characteristic thermal expansion properties as that of the printed circuit to with it is affixed. Solder pads are placed in offset pairs and interface board material is removed such that the combination causes the interface board to flex from the forces caused by the differing expansion coefficients of the solder, the package and the printed circuit boards. The configuration causes the relative movement between the leadless carrier and the printed circuit board to occur along a length of epoxy and glass board material by bending the epoxy and glass as opposed to applying tensional or compressive forces to the solder joints.