Patent ID: 6717328
Filing Date: 2004-04-06
Classification: H03D,Y10T

Abstract:
A piezoelectric resonator made of a piezoelectric material, wherein the temperature coefficient &egr;TC of the capacitance of the piezoelectric material, the bandwidth ratio &Dgr;f/fo, the temperature coefficient FrTC of the resonance frequency, the temperature coefficient FaTC of the anti-resonance frequency, and a target value &agr; for the temperature coefficient of the center frequency satisfy the following expression:|(FrTC+FaTC)/2+KÃ—&egr;TCÃ—(&Dgr;f/fo)|&lE;&agr;where K=a coefficient determined according to the impedance at the midpoint between Fr and Fa; &egr;TC=AÃ—(the amount of change in capacitance in a measured temperature range)/(the capacitance at a reference temperatureÃ—the measured temperature range); &Dgr;f/fo=(Fa at the reference temperatureâˆ’Fr at the reference temperature)/(fo at the reference temperature); FrTC=AÃ—(the amount of change in Fr in the measured temperature range)/(Fr at the reference temperatureÃ—the measured temperature range); FaTC=AÃ—(the amount of change in Fa in the measured temperature range)/(Fa at the reference temperatureÃ—the measured temperature range); and A=a coefficient of +1 for a positive temperature coefficient and âˆ’1 for a negative temperature coefficient.