Resonator, oscillator and communication device

#The present document contains subject matter related to Japanese Patent Application No. 2007-255864 filed in the Japanese Patent Office on Sep. 28, 2007, the entire content of which being incorporated herein by reference.

#1. Field of the Invention

#The present invention relates to a resonator making use of mechanical resonance, an oscillator using the resonator, and a communication device provided with the oscillator.

#FIGS. 1A and 1B are a plan view and a sectional view taken along line A-A, respectively, of an exemplary unit resonator element adopted to a resonator of an embodiment of the present invention;

#FIG. 2 is a schematic plan view showing a first embodiment of a resonator of the present invention;

#FIG. 3 is an enlarged view of a main portion of the resonator shown in FIG. 2;

#Paragraphs below will explain embodiments of the present invention, referring to the drawings.

#First, a configuration and a principle of operation of a single unit of resonator element composing a resonator of this embodiment will be explained, referring to FIGS. 1A and 1B. The resonator element to be brought into focus in this embodiment is a micro-resonator element of micro scale and nano scale. A resonator element 21 exemplified in this embodiment is a mechanical resonator element having an oscillating component (so-called beam) 24 which functions as oscillator and is held aerially over the substrate 22 with the aid of support components 23 at both ends thereof, and an input electrode (so-called input signal line) 26 and an output electrode (so-called output signal line) 27, which serve as the lower electrodes, fixed on the substrate 22 such that the electrodes cross the oscillating component 24 while keeping a space 25 in between, as described previously. Support components 23 are formed as being connected to electroconductive pedestals 28 on the substrate 22.

#The resonator element 21 oscillates at a resonance frequency specific to the oscillating component 24, when a signal inputted from the input electrode 26 induces external force based on electrostatic force to the oscillating component 24 to which direct-current (DC) bias voltage V is applied, and the oscillation is transmitted as a signal via the micro space 25 to the output electrode 27. The resonator element 21 is a resonator element making use of flexural oscillation of the secondary mode.