JPH03126312A - Surface acoustic wave rejector - Google Patents

Abstract

PURPOSE:To miniaturize the size of the device small and to facilitate the adjustment of attenuation by arranging a resistor connected between an input terminal and an output terminal onto a same piezoelectric substrate as a 2-port surface acoustic wave resonator after applying circuit integration to the resistor. CONSTITUTION:A resistive element 16 is formed on a same piezoelectric substrate 11 provided with a lateral mode resonance 2-port surface acoustic wave resonator comprising interdigital electrodes 12, 13 and reflectors 14, 15. The resistive element 16 is a resistor of meander line state metallic thin film such as an aluminum thin film forming a surface acoustic wave element or a resistor made of a carbon by sputtering or the like. Then the resistance adjustment during the assembling of a surface acoustic wave rejecter is implemented by the laser trimming technology. Since the resistive element is formed on the same piezoelectric substrate as the surface acoustic wave resonator, the device is made remarkably small and the resistance is easily adjusted.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a jetter using a surface acoustic wave resonator,
In particular, it relates to an integrated structure of external elements.

[Conventional technology]

Conventionally, this kind of glue jetter has been equipped with a guard, as shown in Fig. 3.
A two-port surface acoustic wave resonator is provided with an input interdigital electrode 12 and an output interdigital electrode 13 on a piezoelectric substrate 11,
Reflectors 14.15 are provided on both sides of these electrodes 12.13, and an installation terminal 19 is connected to one end of the electrodes 12.13. In addition, the other ends of the electrodes 12.13 are connected to external input terminals 17' and output terminals 18', and a resistor 16' is connected externally between the input and output terminals 17' and 18' to form a discrete configuration. Was.

[Problem to be solved by the invention]

The conventional surface acoustic wave rejector described above is composed of a two-port surface acoustic wave resonator and an externally connected resistance element 16', so the mounting shape is large and the resistance value has to be adjusted to adjust the attenuation amount of the rejector. There were drawbacks such as the need for changes.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate such drawbacks, reduce the size of the device, and provide a surface acoustic wave rejector that facilitates adjustment of the amount of attenuation.

[Means to solve the problem]

The configuration of the present invention includes a two-port surface acoustic wave resonator on a piezoelectric substrate, in which interdigital electrodes for input and interdigital electrodes for output are connected, and an input terminal of the two-port surface acoustic wave resonator. A surface acoustic wave rejector including a resistor connected between output terminals, characterized in that the resistor is integrated and disposed on the same piezoelectric substrate as the two-point surface acoustic wave resonator. .

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic plan view of an embodiment of the present invention. A resistive element 16 is formed on the same piezoelectric substrate 11 on which a transverse mode resonant two-boat surface acoustic wave resonator consisting of interdigital electrodes 12.13 and reflectors 14.15 is provided. The resistive element 16 can be formed of a resistor formed by forming a meander line of a metal thin film such as an aluminum thin film that forms a conventional surface acoustic wave element, or a resistor formed by sputtering carbon or the like.

FIG. 2 is a schematic plan view of a second embodiment of the invention.

In this embodiment, a two-point surface acoustic wave resonator has interdigital electrodes 22, 23 and their reflectors 24, 25, which constitute a transverse mode resonance type rather than a longitudinal mode resonance type as shown in FIG. However, a configuration in which the resistor 16 is provided on the piezoelectric substrate 11 as in FIG. 1 is also possible.

Note that resistance adjustment during assembly of the surface acoustic wave rejector can be easily achieved by using laser trimming technology that has already been implemented in HIC and the like.

〔Effect of the invention〕

As explained above, according to the present invention, by forming the resistive element, which was conventionally attached externally, on the same piezoelectric substrate as the surface acoustic wave resonator, it is possible to significantly downsize the device. Furthermore, the adjustment of the resistance value, which was conventionally required after assembly, can be done during the assembly of the surface acoustic wave rejector, eliminating the need for any adjustment at the customer's site, and also making it possible to solidify the rejector.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view of one embodiment of the surface acoustic wave rejector of the present invention, FIG. 2 is a schematic plan view of another embodiment of the present invention, and FIG. 3 is an example of a conventional surface acoustic wave rejector. FIG. 11... Piezoelectric substrate, 12.13, 22.23... Interdigital electrodes 14, 15.24.25... Reflector, 16
．． 16'...Resistance element, 17.17'...Input terminal, 18.18'...Output terminal.

Claims (1)

[Claims] A two-port surface acoustic wave resonator in which input interdigital electrodes and output interdigital electrodes are connected on a piezoelectric substrate;
In a surface acoustic wave rejector including a resistor connected between an input terminal and an output terminal of a port surface acoustic wave resonator, the resistor is integrated and arranged on the same piezoelectric substrate as the two-port surface acoustic wave resonator. A surface acoustic wave rejector characterized by: