Abstract: A low phase noise dual mode resonator and a method of making and using said resonator is disclosed. The dual mode resonator is capable of sustaining two frequency vibration modes simultaneously. The two frequency vibration modes are capable of exhibit non-linear coupling when one is driven at a higher voltage than the other. The dual mode resonator is configured such that the ratio of the two vibration frequency modes is a value that maximizes the non-linear coupling effect. As a result of the non-linear effect, the phase noise on the mode that is not overdriven is reduced.

Abstract: A low phase noise dual mode resonator and a method of making and using said resonator is disclosed. The dual mode resonator is capable of sustaining two frequency vibration modes simultaneously. The two frequency vibration modes are capable of exhibit non-linear coupling when one is driven at a higher voltage than the other. The dual mode resonator is configured such that the ratio of the two vibration frequency modes is a value that maximizes the non-linear coupling effect. As a result of the non-linear effect, the phase noise on the mode that is not overdriven is reduced.

Abstract: Double-sided, single-sided and ring electrode mesa resonators are provided that operate in the difficult 3 GHZ frequency with an electrode-free resonator area that serves as an energy-trapping area. The double-sided electrode-free resonator device is a double-sided mesa resonator plate, top and bottom wells, a mesa, and top and bottom electrodes deposited in such a way that the electrodes cover the plate surface and surround the mesa, which allows the mesa to protrude above the electrodes and provide an electrode-free resonator area. The top and bottom electrodes, which are acoustically coupled and controlled by acoustic gaps, create an electro-magnetic field and an excitation voltage within a vibrating area of the resonator plate generates an acoustic energy which is trapped within the resonator area and confined to the resonator area to minimize a leakage of the acoustic energy and provide a high Q factor at 3 GHz.

Abstract: Methods are included for determining deviations from &phgr;=0° in test resonators based on the quasi-pure modes' displacement ratio variations with &phgr; angle. A direct relationship between deviation from &phgr;=0° and the c-mode displacement ratio has been observed, so that the larger the deviation from &phgr;=0°, then the larger is the change in the normalized frequency of the c-mode upon immersion in, or contact with, a fluid. The method includes measuring &thgr; and &phgr; angles in reference resonators with different small &phgr; angles and quasi-pure mode frequencies of reference resonators in both air and a test fluid at ambient temperatures, calculating the normalized frequency changes between the air and fluid measurements as a reference point, measuring the test resonator in air then in the fluid and comparing the results.

Abstract: Methods are provided for determining deviations from &phgr;=0° in test resonators based on the quasi-pure modes' displacement ratio variations with 4 angle. A direct relationship between deviation from &phgr;=0° and the c-mode displacement ratio has been observed, so that the larger the deviation from &phgr;=0°, then the larger is the change in the normalized frequency of the c-mode upon immersion in, or contact with, a fluid. The method comprises measuring &thgr; and &phgr; angles in reference resonators with different small &phgr; angles and quasi-pure mode frequencies of reference resonators in both air and a test fluid at ambient temperatures, calculating the normalized frequency changes between the air and fluid measurements as a reference point, measuring the test resonator in air then in the fluid and comparing the results.

Abstract: Techniques for determining the properties of a liquid include placing one or more acoustic crystal resonators in contact with the fluid. An oscillator circuit drives each of the resonators at one or more different modes. A frequency counter connected to the oscillator monitors the operating frequencies of the resonators before and after the surfaces are placed in contact with the liquid. A computer, which is responsive to the outputs of the frequency counter, includes a liquid property system for determining difference frequencies by comparing the operating frequencies measured by the frequency counter with predetermined reference frequencies. The computer calculates the properties of the liquid from the difference frequencies.

Abstract: A technique of determining the properties of a liquid. One or more resonators are exposed to air or another reference fluid of known properties. Oscillator circuits drive the resonators at at least two different frequencies. Frequency counters measure the fluid-operating frequencies of the resonators while they are in contact with the reference fluid. The resonators are then immersed in liquid as the oscillator circuits drive the resonators. The liquid-operating frequencies are measured by the frequency counters while the resonators are in contact with the liquid. A computer compares the fluid-operating frequencies and the liquid-operating frequencies to obtain difference frequencies that are independent functions of the liquid's properties. A computer determines the liquid properties from the difference frequencies.

Abstract: An improved quartz resonator is obtaind using a mask which is kept in intte contact with the quartz substrate during the electrode metallization.

Abstract: A quartz crystal resonator is excited in two different modes at the same time such that the mass change and the temperature change can be measured independently. In using such a quartz crystal the change in mass can be calculated accurately and in real time, independent of temperature effects.

Abstract: A guided artillery projectile is provided for use in improving its accuracy while spinning. The projectile includes an artillery shell, a plurality of movable fins, fin actuators for two-dimensional steering, a fin control for the fin actuators, and a guidance unit for the fin control. A method of guiding an artillery projectile is also provided.

Abstract: A chemical/biological sensor is formed from a coated microresonator array. In operation, both mass changes and temperature changes due to the presence of a particular substance or agent will cause an output frequency change which can be attributed to that particular substance or agent. Further, the frequency changes caused by mass loading can be distinguished from those frequency changes caused by temperature changes due to the heat from adsorption or reaction. This is because frequency changes due to mass loading are independent from frequency changes due to temperature changes, and therefore, by measuring the frequency changes of the microresonators coated with a variety of adsorbers, one can independently separate the two types of frequency changes, and, thereby, identify and quantify the adsorbing agents.

Abstract: A highly sensitive thermal sensor is disclosed which uses a thermally isolated, thermometer cut quartz microresonator that is configured to be exposed to a radiant energy source.

Abstract: An oscillator is isolated from external mechanical and thermal effects by rrounding the oscillator on all sides with an aerogel insulation structure that provides both thermal insulation and vibrational isolation above some predetermined low frequency limit which is a function of the mass of the oscillator and the nature of the aerogel insulation structure.

Abstract: A piezoelectric material langasite, having a defect free surface is obtai by polishing the surface of the material with a colloidal silica suspension diluted with water to about 10 to 30% concentration by weight and etching the surface of the polished piezoelectric material in an approximate 1:50:150 solution of HCl:HF:H.sub.2 O at about 70.degree. C.

Abstract: A crystal resonator in an electrodeless configuration is electrically levitated by a resonant circuit. A quartz plate (or other piezoelectric substrate) is levitated by a resonant circuit which includes an inductor that is external to a housing and a parallel plate capacitor that is inside the housing. The parallel plate capacitor consists of three plates, two of which are mounted edge to edge on a nonconductive housing with a small space between them and the third of which is a conducting surface on the quartz plate being levitated. This is an open circuit configuration which requires no feedback sensor circuitry. The resonator, after being levitated, is then electrically addressed in any number of electrodeless configurations.

Abstract: An improved crystal resonator package is provided using high purity alumi.

Abstract: The present invention provides for methods of increasing the frequency vs. temperature ("f vs. T") stability of Oven Controlled Crystal Oscillators to levels which are superior to atomic frequency standards and 100 to 10,000 times higher than that currently available from the best crystal oscillators. This method encompasses the steps of making an SC-cut quartz resonator with upper and lower turnover temperatures at or near the resonator's inflection temperature, inserting the resonator into a high-stability oscillator circuit, placing the circuit into a high-stability, high thermal gain oven and adjusting the oven temperature to a set-point at or near one of the resonator's turnover temperatures.

Abstract: A neutron radiation insensitive crystal oscillator. The device includes two crystals with neutron sensitivity coefficients of opposite sign. The crystals may be connected either in parallel or series relationships. The addition of tuning reactances to the circuit permits control of the circuit's overall resonance.

Abstract: The aging and radiation induced frequency shifts of quartz crystal oscillrs are minimized by using oscillator circuits in which the DC voltage applied to the quartz crystal is about zero. This results in reduced movement of impurity ions which generally cause such shifts.

Abstract: An oscillator is isolated from external mechanical and thermal effects by surrounding the oscillator on all sides with a thermally insulating medium such as an aerogel insulation structure that provides both thermal insulation and vibrational isolation. Power is supplied to the crystal oscillator without wires. Wires are eliminated by using modulated microwaves or millimeter waves to transmit power and signals into and out of the oscillators, such as with small, efficient transceivers utilizing microwave or millimeter-wave integrated circuits or use of solid-state light sources and photodetectors in combination with thermal insulation which is transparent to the wavelengths of the electromagnetic radiation.