Motorola Corporation

Weiping Zhang

Kevin L Haas

Aristotelis S Arvanitis

Sang Hoon Kim

Beverly A Carroll

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.

Electrode edge wave patterns for piezoelectric resonator

A method of rotating a non-temperature compensated Bechmann curve of a quartz strip. The method includes the steps of determining (102) whether a crystallographic orientation of an AT cut quartz strip is within a desired specification; selecting (104) a predetermined nominal electrode coverage having a nominal electrode width for an in-specification AT cut quartz strip; and tuning (106) an out of specification crystallographic orientation, by: adjusting (108) the electrode width with respect to the nominal electrode width, to bring the out-of-specification crystallographic orientation of an out-of-specification AT cut crystal quartz to within a desired specification having an in-specification Bechmann curve with an inflection point; and rotating (110) an out-of-specification Bechmann curve about the inflection point to substantially approach the desired in-specification Bechmann curve.

Growing community of inventors

Arlington Heights, IL, United States of America

Weiping Zhang