Abstract: A method for forming a dielectric layer onto a substrate having a silicon surface includes initially depositing an oxidizable metal thin film onto the surface and thereafter depositing a thin film of a metal titanate compound, such as the zirconium titanate. The metal thin film is preferably formed of tantalum, titanium or zirconium. Following deposition of the metal titanate thin film, the metal titanate is annealed by heating in an oxidizing atmosphere at a temperature effective to recrystalize the titanate to increase the dielectric properties. During annealing, the metal film reacts with oxygen to form a metal oxide thin film intermediate the metal titanate thin film and the silicon surface. The oxidation of the metal thin film inhibits oxidation of the underlying silicon that would otherwise reduce the effective capacitance of the dielectric layer.

Abstract: An acoustic wave ladder filter (30) with lossy inductances (42) connected in parallel with resonators (40). Shunt sections (36,37) of the ladder filter (30) include impedance inverters having pass frequencies within the stopband of series resonators (33,34,35). The filter (30) additionally includes variable capacitors (44) connected in parallel with the inductances (42) to provide adjustment capabilities. The use of lossy inductances (42) actually increases effective coupling coefficient of the filter (30) and improves insertion loss thereby allowing improved design flexibility.

Abstract: A ceramic filter (100) with integrated harmonic response suppression has a ceramic monolithic block filter having a predetermined passband defined by tuned resonators located between an input and an output (116); and at least one of a harmonic trap filter, a lowpass filter and a lowpass microstrip filter, each having an inductive and a capacitive component. This is achievable with a design which incorporates an integrated harmonic response suppression filter directly in or on the dielectric ceramic monolithic block. This can result in a substantial savings in space, cost, and part count in an electronic telecommunications device.

Abstract: A method (38) for packaging a microelectronic device (10) and a device (10) packaged by the method (38). The method (38) includes a step of providing (42) a first material (16) on an active surface of the microelectronic device (10). The first material (16) has a first temperature coefficient of expansion. The method (38) also includes steps of heating (46) the microelectronic device (10) and the first material (16) to a predetermined first temperature and molding (48) a second material (20) about the microelectronic device (10) and the first material (16). The second material (20) has a second temperature coefficient of expansion less than that of the first material (16). A final step of cooling (50) the first material (16), the second material (20) and the microelectronic device (10) provides a packaged microelectronic device (30).

Abstract: A piezoelectric resonator (10) with electrodes (14) having a periodic pattern (28) along a portion of an edge (30) of at least one of the electrodes (26). The periodic pattern (28) has a periodicity that destructively interferes with the undesirable vibrational mode. For example, a rectangular AT-cut quartz resonator, which vibrates in a thickness-shear mode may also possess undesirable flexure and face-shear modes. These modes not only present undesirable spurious frequencies, they also change over temperature, disturbing a frequency-temperature response (16) of the quartz crystal. The periodic pattern (28) substantially reduces these undesirable modes, providing a more uniform frequency-temperature response which is beneficial in temperature compensated crystal oscillator applications.

Abstract: A resonator (104) including a piezoelectric plate (102) with an electrode (108) having a random pattern (100) along a portion of an edge of the electrode (108). The random pattern (100) dampens or destructively interferes with undesirable and inharmonic vibrational modes. For example, a rectangular AT-cut quartz resonator, which vibrates in a thickness-shear mode may also possess undesirable flexure and face-shear modes. These modes not only present undesirable spurious frequencies, they also change over temperature, disturbing a frequency-ternperature response of the resonator. The random pattern (100) causes diffuse and/or specular scattering to reduce these undesirable modes, providing a more uniform frequency-temperature response which is beneficial in temperature compensated crystal oscillator applications.

Abstract: A method for packaging an acoustic wave filter die, and an acoustic wave filter die packaged by the method. The method includes steps of providing an acoustic wave filter die having an active area disposed on a first surface thereof, providing a leadframe including a die flag and sealing the first surface to the die flag. The method also includes steps of molding a plastic package body about the die and the die flag and singulating the plastic body, the die and the die flag. The molding step desirably includes substeps of placing the acoustic wave filter die sealed to the leadframe in a mold, applying a thermosetting plastic material at a suitable temperature less than the glass transition temperature and at a suitable pressure to the acoustic wave filter die sealed to the leadframe in the mold and maintaining the suitable temperature for a suitable period of time.

Abstract: A method of producing a glass/metal package where a glass portion of the package is built up around a provided leadframe (10) using applications of solderable and glass pastes (20) which are subsequently fired (30). The glass paste and leadframe are chosen to have similar coefficients of expansion and the leadframe is pretreated to degasify and control oxidation of the metal to promote glass adhesion to the leadframe and prevent microcracking at a glass/metal interface. A seal ring is applied to the glass paste (40) and a lid is attached to the seal ring (50). The package is used to provide an sealed inert internal environment for sensitive electronic components such as a piezoelectric element. The package may be configured for leaded or surface mounting (60).

Abstract: A circuit (10) for driving a piezoelectric transformer (12) in a phase locked mode without using an external reference signal. The circuit (10) utilizes a 555 timer circuit operated in a stable mode which is responsive to a feedback phase signal (18) coupled from an output signal (20) of the piezoelectric transformer (12). The feedback phase signal (18) overpowers the trigger circuit of the timer to phase lock the timer to an output of the piezoelectric transformer (12) at a resonant frequency of the piezoelectric transformer (12). The circuit (10) provides a simplified phase lock circuit without the need for a typical PLL configuration.

Abstract: A voltage controlled oscillator (10) operable on two widely separated frequency bands of 800 MHz and 1.9 GHz, for example. The two operable frequency modes are controlled by changing base bias voltages on at least two transistors with commonly connected emitters. A base circuit of each transistor is connected to an independent resonator and tuning element and shares a common feedback reactance. By increasing a base bias voltage of first transistor relative the a second transistor, an associated first base circuit is turned on and allowed to oscillate at a first frequency while a second base circuit is turned off preventing oscillation at a second frequency. Correspondingly, by decreasing the base bias voltage the first base circuit is turned off and the second base circuit is turned on. The transistors share a common collector connection and output providing either one of the two frequencies.

Abstract: A communication device including a plurality of frequency synthesizers (24, 28, 30). At least one of the frequency synthesizers (24) is driven with a reference frequency from a crystal oscillator (58). The at least one frequency synthesizer (24) includes a phase locked loop with a fractional-N divider (48) which is programmed by a control circuit (64) to vary as a function of temperature compensation, frequency compensation, and a frequency multiplication factor. The output (46) of the at least one frequency synthesizer (24) is used to provide a compensated reference frequency input for the remaining frequency synthesizers (28, 30). The radio provides all the frequency synthesizers (24, 28, 30) with temperature and frequency compensation using a reference frequency from a crystal oscillator (58) and only one high resolution frequency compensating synthesizer (24).

Abstract: An acoustic wave resonator filter (10) provides series and shunt resonator elements (22, 24) in a ladder network. The series elements (22) are configured in a lowpass configuration. The shunt elements (24) act as impedance inverters in a passband of the filter and they series resonate at an antiresonant frequency of the series elements (22) in a stopband which provides additional isolation. The electrodes (14) of the elements (22, 24) are of a metal thickness which improve the losses of a series resonant frequency in a passband which improves insertion loss. However, any increase in loss near the antiresonant frequency is compensated by the reduced loss near the resonant frequency of the shunt elements (24).

Abstract: A ceramic transverse-electromagnetic-mode filter having a waveguide cavity mode frequency shifting void and method of tuning same is provided. The ceramic filter includes a filter body (200) comprising a block of dielectric material and having top (202), bottom (204) and four side surfaces (206, 208, 210, 212) including vertical edges (214). The filter also has metallized through-holes providing transverse-electromagnetic-mode resonators (216). At least one vertical portion in proximity to the vertical edges (214) of the block on at least one of the side surfaces is unmetallized providing a waveguide cavity mode frequency shifting void (218). The waveguide cavity mode frequency shifting void (218) shifts a set of parasitic spurious responses in the filter frequency response curve to a lower frequency while simultaneously maintaining a desired transverse-electromagnetic-mode passband.

Abstract: A voltage controlled oscillator operable on two widely separated frequency bands, such as 900 MHz and 1.8 GHz for example. The voltage controlled oscillator includes two negative resistance generators (32, 34) which share a common tunable tank circuit (26) and a common impedance matched combiner circuit (28) which provides the RF output (36). The VCO uses only one varactor (30) to tune both frequency bands. Separate negative resistance generators (32, 34) are used to provide optimum frequency selectivity within each frequency band.

Abstract: A high frequency acoustic wave piezoelectric device (10) having parallel etched channels cut into a surface of a piezoelectric substrate so as to form micromachined ridges (20). Top electrodes (30) are located on tops (26) of the ridges (20) and bottom electrodes (32) are located on bottoms of the channels in spacings (22) between ridges (20). The top and bottom electrodes (30, 32) are offset from each other and substantially non-opposing. The electrodes (30, 32) generate a sufficient vertical electrical field (38) when driven to cause the ridges (20) to resonate. A height (28) of the ridges (20) define the operating frequency. The ridges (20) can be made small enough to produce frequencies well over 100 MHz in a fundamental bulk acoustic wave mode.

Abstract: A multilayered ceramic integrated sensor 200 for monitoring auto exhaust gases is capable of existing in the relatively harsh environments of the exhaust stream of an internal combustion engine. The integrated sensor 200 may include discrete devices such as an oxygen sensor 104, a hydrogen sensor 206, an NO.sub.x sensor 208, and a carbon monoxide sensor 210. The device 200 may further include a temperature sensor 202 as well as total combustion calorimetric sensor 102. The multilayered ceramic integrated sensor may be fabricated from a plurality of layers of ceramic material disposed in stacked relationship with respect to one another.

Abstract: A method for making an acoustic wave device (500, 600, 701, 801, 901, 1001), and an acoustic wave device (500, 600, 701, 801, 901, 1001) made by the method. The method comprises steps of providing a substrate (11) capable of supporting acoustic wave propagation and disposing a first transducer (518, 518') thereon. Disposing the first transducer (518, 518') includes disposing first through fourth electrode groups on the substrate. The first group couples to a first electrical interconnection (17+). The second group couples to a second electrical interconnection (17-). The third group couples to a common electrical interconnection and is interleaved with the first group of electrodes. The fourth group couples to the common electrical interconnection and is interleaved with the second group.

Abstract: A low loss high frequency transmitting/receiving switching module (100) having an input and output port (106,110), that individually may be connected to an antenna or external port (108,112) by applying an appropriate bias potential to a switching circuit (140). The switching circuit (140) is designed to operate with only a single diode (130). This is accomplished by using two, four-port 3 db directional couplers (102,104) connected with two coupling lines (114,118). The switching diode (130) is used to add or delete a transmission line (142) in one of the coupling lines (118) to proved a signal phase shift. The switching circuit (140) switches in or out a 180 degree phase shift to change the phase relationship between signals in the two sets of coupling lines (114,116,118,120) to determine which ports (106,108,110,112) of the directional couplers (102,104) are interconnected.

Abstract: A temperature compensation circuit (10) for a crystal oscillator module (12) used in a communication device (200). An existing microcontroller (210) of the communication device (200) is used to provide temperature compensating digital data (30) for a crystal oscillator (18). The temperature compensating digital data (30) is converted to a temperature compensation signal (22) in a digital-to-analog converter (32) which controls the crystal oscillator frequency. The crystal oscillator module (12) includes an onboard voltage regulator (34) which supplies a characterized regulated voltage (36) to the digital-to-analog converter (32) such that the temperature compensation signal (22) from the digital-to-analog converter (32) is inherently corrected for voltage variations in the voltage regulator (34). Changes in the temperature compensation of the crystal oscillator (18) are allowed only when the communication device (200) is not transmitting or receiving.

Abstract: A frequency synthesizer (10) including a synthesizer loop (12) with a fractional-N divider (14), and including a divider control circuit (18) and a combining circuit (22). The divider control circuit (18) provides a variable divide value (20) to the divider (14). The carry values of two accumulators (24, 26) having differing accumulator lengths are applied in parallel to the combining circuit (22). Each of the accumulators (24, 26) provides a portion of a desired fractional divide value (20). The combining circuit (22) also adds an integer divide value (36) to the fractional divide value (16). By coupling the accumulators (24, 26) in parallel, a high frequency resolution with minimal spurious frequencies is achieved, using a simple, low cost circuit.