阅读说明：本技术 谐振器及滤波器 (Resonator and filter ) 是由 不公告发明人 于 2021-11-08 设计创作，主要内容包括：本申请涉及滤波器技术领域,公开一种谐振器,包括：压电层、第一电极、第二电极、第三电极和第二电极；压电层一侧与第一电极的一侧连接；第一电极另一侧连接有第三电极；第二电极连接压电层的另一侧；第一电极、第二电极和压电层在谐振器的厚度方向上的重叠区域构成谐振器的有效区域；第三电极在谐振器的横向方向上位于有效区域之外；第四电极与第二电极连接,第四电极与压电层位于第二电极的同侧且第四电极与第一电极之间绝缘。采用本申请提供的谐振器,能够在谐振器电极变薄的情况下,在不影响谐振器的谐振同时不会增大谐振器的有效电阻。本申请还公开一种滤波器。(The application relates to the technical field of filters, and discloses a resonator, including: a piezoelectric layer, a first electrode, a second electrode, a third electrode, and a second electrode; one side of the piezoelectric layer is connected with one side of the first electrode; the other side of the first electrode is connected with a third electrode; the second electrode is connected with the other side of the piezoelectric layer; the overlapping area of the first electrode, the second electrode and the piezoelectric layer in the thickness direction of the resonator forms an effective area of the resonator; the third electrode is located outside the effective area in the lateral direction of the resonator; the fourth electrode is connected with the second electrode, the fourth electrode and the piezoelectric layer are positioned on the same side of the second electrode, and the fourth electrode is insulated from the first electrode. By adopting the resonator provided by the application, the effective resistance of the resonator can not be increased while the resonance of the resonator is not influenced under the condition that the electrode of the resonator is thinned. The application also discloses a filter.)

1. A resonator, comprising:

a piezoelectric layer, one side of which is connected to one side of the first electrode;

the other side of the first electrode is connected with a third electrode;

a second electrode connected to the other side of the piezoelectric layer; the overlapping area of the first electrode, the second electrode and the piezoelectric layer in the thickness direction of the resonator forms an effective area of the resonator;

the third electrode is positioned outside the effective area in the transverse direction of the resonator;

and the fourth electrode is connected with the second electrode, the fourth electrode and the piezoelectric layer are positioned on the same side of the second electrode, and the fourth electrode is insulated from the first electrode.

2. The resonator according to claim 1, wherein a thickness of the third electrode is 1.5 times or more a thickness of the first electrode, or wherein a thickness of the third electrode is 1.5 times or more a thickness of the second electrode.

3. The resonator according to claim 1, characterized in that the distance between the third electrode and the active area is greater than or equal to 2 micrometers in the lateral direction of the resonator.

4. The resonator according to claim 1, characterized in that there is a gap between the fourth electrode and the first electrode in the lateral direction of the resonator and a gap between the fourth electrode and the third electrode in the lateral direction of the resonator.

5. The resonator of claim 1, wherein the third electrode is made of copper, aluminum, or gold.

6. The resonator according to any of claims 1 to 5, characterized in that the piezoelectric layer, the first electrode, the second electrode, the third electrode and the fourth electrode constitute a bulk acoustic wave resonant structure; the resonator further comprises a support layer, and the bulk acoustic wave resonant structure is arranged on the support layer.

7. A filter, comprising:

a first resonator, a second electrode of the first resonator being an input terminal of the filter;

a second resonator, a second electrode of the second resonator being an output terminal of the filter;

a third resonator, a second electrode of the third resonator being a ground terminal of the filter;

the first electrode of the first resonator, the first electrode of the second resonator and the first electrode of the third resonator are communicated with each other;

the first resonator, the second resonator and the third resonator are all resonators as claimed in any one of claims 1 to 6.

8. The filter of claim 7, wherein the third electrode of the first resonator, the third electrode of the second resonator, and the third electrode of the third resonator are in communication with each other.

9. The filter of claim 7, comprising: and the third electrodes of the first resonator, the second resonator and the third resonator are provided with notches.

10. The filter of claim 9, wherein the gap is less than or equal to 4 across the first resonator, the second resonator, or the third resonator.

Technical Field

The present invention relates to the field of filter technology, and for example, to a resonator and a filter.

Background

With the evolution of communication technology and the improvement of data transmission rate, the requirements on the performance of a filter in a radio frequency communication system are higher and higher, wherein the requirements include (1) the power bearing capacity of the filter is increased from the original 29dBm to 32 dBm; (2) the carrier frequency increases from the original maximum 2.7GHz to the present 6.5 GHz. The resonators are used as core devices of filters, and the size of the resonators needs to be reduced to increase the carrier frequency. The reduction in size of the resonator includes a reduction in thickness of the resonator, i.e., a thinning of the thickness of the electrodes of the resonator. As shown in fig. 1, 2 and 3, fig. 1 is a schematic structural diagram of a conventional resonator, and fig. 2 is a schematic sectional view of a cross section a-a of the conventional resonator, and the resonator includes a first electrode 1, a second electrode 3, a piezoelectric layer 4 and a support layer 6. Fig. 3 is a schematic diagram of a filter in the prior art.

In the process of implementing the embodiment of the invention, the following problems are found in the related art at least:

thinning the electrode thickness of the resonator increases the effective resistance of the resonator, resulting in increased insertion loss of the filter.

Disclosure of Invention

The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed embodiments. This summary is not an extensive overview nor is intended to identify key/critical elements or to delineate the scope of such embodiments but rather as a prelude to the more detailed description that is presented later.

Embodiments of the present invention provide a resonator and a filter, so that the effective resistance of the resonator is not increased when the thickness of an electrode of the resonator is reduced.

In some embodiments, the resonator comprises: a piezoelectric layer, one side of which is connected to one side of the first electrode; the other side of the first electrode is connected with a third electrode; a second electrode connected to the other side of the piezoelectric layer; the overlapping area of the first electrode, the second electrode and the piezoelectric layer in the thickness direction of the resonator forms an effective area of the resonator; the third electrode is positioned outside the effective area in the transverse direction of the resonator; and the fourth electrode is connected with the second electrode, the fourth electrode and the piezoelectric layer are positioned on the same side of the second electrode, and the fourth electrode is insulated from the first electrode.

In some embodiments, the thickness of the third electrode is 1.5 times or more the thickness of the first electrode, or the thickness of the third electrode is 1.5 times or more the thickness of the second electrode.

In some embodiments, the distance between the third electrode and the active area in the lateral direction of the resonator is greater than or equal to 2 microns.

In some embodiments, there is a gap between the fourth electrode and the first electrode in a lateral direction of the resonator, and there is a gap between the fourth electrode and the third electrode in the lateral direction of the resonator.

In some embodiments, the third electrode is made of copper, aluminum, or gold.

In some embodiments, the piezoelectric layer, the first electrode, the second electrode, the third electrode, and the fourth electrode constitute a bulk acoustic wave resonant structure; the resonator further comprises a support layer, and the bulk acoustic wave resonant structure is arranged on the support layer.

In some embodiments, the filter comprises: a first resonator, a second electrode of the first resonator being an input terminal of the filter; a second electrode of the second resonator is an output end of the filter; a second electrode of the third resonator is a grounding end of the filter; the first electrode of the first resonator, the first electrode of the second resonator and the first electrode of the third resonator are communicated with each other; the first resonator, the second resonator and the third resonator are all the resonators described above.

In some embodiments, the third electrode of the first resonator, the third electrode of the second resonator, and the third electrode of the third resonator are in communication with each other.

In some embodiments, the third electrodes of the first resonator, the second resonator, and the third resonator are provided with notches.

In some embodiments, the gap is less than or equal to 4 on the first resonator, the second resonator, or the third resonator.

The resonator and the filter provided by the embodiment of the invention can realize the following technical effects:

according to the embodiment of the invention, the first electrode of the resonator is connected with the third electrode, so that the thickness of the first electrode of the resonator is increased, and the second electrode of the resonator is connected with the fourth electrode, so that the thickness of the second electrode of the resonator is increased, and the thickness of the electrode outside the effective area of the resonator is increased, therefore, the effective resistance of the resonator can not be increased while the resonance of the resonator is not influenced under the condition that the electrode of the resonator is thinned.

The foregoing general description and the following description are exemplary and explanatory only and are not restrictive of the application.

Drawings

One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the accompanying drawings and not in limitation thereof, in which elements having the same reference numeral designations are shown as like elements and not in limitation thereof, and wherein:

FIG. 1 is a schematic diagram of a prior art resonator;

FIG. 2 is a schematic cross-sectional view of a prior art resonator taken along section A-A;

FIG. 3 is a schematic diagram of a prior art filter;

FIG. 4 is a schematic structural diagram of a resonator provided in an embodiment of the present invention;

FIG. 5 is a cross-sectional view of a resonator in cross-section B-B according to an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of another resonator provided in accordance with an embodiment of the present invention;

FIG. 7 is a cross-sectional schematic view of a C-C cross-section of another resonator provided by embodiments of the present invention;

FIG. 8 is a schematic diagram of a filter according to an embodiment of the present invention;

fig. 9 is a schematic structural diagram of another filter provided in the embodiment of the present invention;

fig. 10 is a schematic structural diagram of still another filter provided in an embodiment of the present invention;

figure 11 is a graph of insertion loss as a function of frequency for filters of different thickness electrodes.

Reference numerals:

1. a first electrode; 2. a third electrode; 3. a second electrode; 4. a piezoelectric layer; 5. a fourth electrode; 6. a support layer; 7. lacking gaps; 8. a first resonator; 9. a second resonator; 10. and a third resonator.

Detailed Description

So that the manner in which the features and aspects of the embodiments of the present invention can be understood in detail, a more particular description of the embodiments of the invention, briefly summarized above, may be had by reference to the embodiments, some of which are illustrated in the appended drawings. In the following description of the technology, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, one or more embodiments may be practiced without these details. In other instances, well-known structures and devices may be shown in simplified form in order to simplify the drawing.

The terms "first," "second," and the like in the description and in the claims, and in the drawings, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It should be understood that the data so used may be interchanged under appropriate circumstances such that embodiments of the invention described herein may be used. Furthermore, the terms "comprising" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions.

In the embodiments of the present invention, the terms "upper", "lower", "inner", "middle", "outer", "front", "rear", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings. These terms are used primarily to better describe embodiments of the invention and its embodiments, and are not intended to limit the indicated devices, elements or components to a particular orientation or to be constructed and operated in a particular orientation. Moreover, some of the above terms may be used to indicate other meanings besides the orientation or positional relationship, for example, the term "on" may also be used to indicate some kind of attachment or connection relationship in some cases. Specific meanings of these terms in the embodiments of the present invention may be understood by those skilled in the art according to specific situations.

In addition, the terms "disposed," "connected," and "secured" are to be construed broadly. For example, "connected" may be a fixed connection, a detachable connection, or a unitary construction; can be a mechanical connection, or an electrical connection; may be directly connected, or indirectly connected through intervening media, or may be in internal communication between two devices, elements or components. Specific meanings of the above terms in the embodiments of the present invention can be understood by those of ordinary skill in the art according to specific situations.

The term "plurality" means two or more unless otherwise specified.

In the embodiment of the present invention, the character "/" indicates that the preceding and following objects are in an or relationship. For example, A/B represents: a or B.

The term "and/or" is an associative relationship that describes objects, meaning that three relationships may exist. For example, a and/or B, represents: a or B, or A and B.

It should be noted that, in the case of no conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.

As shown in fig. 4, 5, 6, and 7, an embodiment of the present invention provides a resonator, including: a piezoelectric layer 4, a first electrode 1, a second electrode 3, a third electrode 2, and a fourth electrode 5; one side of the piezoelectric layer 4 is connected to one side of the first electrode 1; the other side of the first electrode 1 is connected with a third electrode 2; the second electrode 3 is connected with the other side of the piezoelectric layer 4; the overlapping area of the first electrode 1, the second electrode 3 and the piezoelectric layer 4 in the thickness direction of the resonator constitutes an effective area of the resonator; the third electrode 2 is located outside the active area in the lateral direction of the resonator; the fourth electrode 5 is connected with the second electrode 3, the fourth electrode 5 and the piezoelectric layer 4 are positioned on the same side of the second electrode 3, and the fourth electrode 5 is insulated from the first electrode 1.

According to the resonator provided by the embodiment of the invention, the first electrode of the resonator is connected with the third electrode, so that the thickness of the first electrode of the resonator is increased, and the second electrode of the resonator is connected with the fourth electrode, so that the thickness of the second electrode of the resonator is increased, and the thickness of the electrode outside the effective area of the resonator is increased, therefore, the effective resistance of the resonator can not be increased while the resonance of the resonator is not influenced under the condition that the electrodes of the resonator are thinned.

Optionally, the fourth electrode 5 abuts the piezoelectric layer 4.

Optionally, the thickness of the third electrode is more than 1.5 times the thickness of the first electrode; or the thickness of the third electrode is more than 1.5 times of the thickness of the second electrode.

Under the condition that the thickness of the third electrode is less than 1.5 times of the thickness of the first electrode or the thickness of the third electrode is less than 1.5 times of the thickness of the second electrode, the resistivity reduction effect of the first electrode is poor, and the structure of the resonator is complex; therefore, the thickness of the third electrode is determined to be 1.5 times or more the thickness of the first electrode; alternatively, determining the thickness of the third electrode to be 1.5 times or more the thickness of the second electrode can significantly reduce the resistivity of the first electrode, thereby significantly reducing the effective resistance of the resonator.

In some embodiments, the first electrode has a thickness of 200 nanometers and the third electrode has a thickness greater than or equal to 300 nanometers. The thickness of the second electrode is 200 nanometers, and the thickness of the third electrode is greater than or equal to 300 nanometers.

Optionally, the thickness of the fourth electrode is more than 1.5 times the thickness of the first electrode; or the thickness of the fourth electrode is more than 1.5 times of the thickness of the second electrode.

In some embodiments, the thickness of the first electrode is 200 nanometers and the thickness of the fourth electrode is greater than or equal to 300 nanometers. The thickness of the second electrode is 200 nanometers, and the thickness of the fourth electrode is greater than or equal to 300 nanometers.

Optionally, a distance between the third electrode and the active area is greater than or equal to 2 microns in a lateral direction of the resonator. In this way, the thickness of the electrodes outside the resonator's active area is increased so that the third electrode does not affect the resonance of the resonator and does not increase the effective resistance of the resonator if the resonator electrodes are thinned.

Alternatively, there is a gap between the fourth electrode 5 and the first electrode 1 in the lateral direction of the resonator, and there is a gap between the fourth electrode 5 and the third electrode 2 in the lateral direction of the resonator.

Because the fourth electrode is connected with the second electrode, and the third electrode is connected with the first electrode, under the condition that a gap exists between the fourth electrode and the first electrode and a gap exists between the fourth electrode and the third electrode, the first electrode and the second electrode can be ensured not to be connected through the fourth electrode or the third electrode, the isolation between the first electrode and the second electrode is ensured, and the short circuit caused by the communication between the first electrode and the second electrode is avoided.

Optionally, the third electrode is made of copper, aluminum or gold. The third electrode is made of materials with high conductivity such as copper, aluminum or gold, and the third electrode is connected with the first electrode, so that the uniformity of current flowing on the whole resonator can be enhanced, the potential difference of the whole resonator is ensured to be uniform, and the resistivity of the resonator is reduced.

Optionally, the piezoelectric layer, the first electrode, the second electrode, the third electrode and the fourth electrode constitute a bulk acoustic wave resonant structure; the resonator further comprises a support layer 6, the bulk acoustic wave resonant structure being arranged on the support layer 6. In this way, the bulk acoustic wave resonant structure can be supported by the support layer.

Optionally, one side of the second electrode is connected to the piezoelectric layer, the other side of the second electrode is connected to the support layer, and the side of the piezoelectric layer connected to the second electrode is simultaneously connected to the support layer.

Optionally, the thickness of the support layer connected to the piezoelectric layer is greater than the thickness of the second electrode.

By adopting the filter provided by the embodiment of the invention, the first electrode of the resonator is connected with the third electrode, so that the thickness of the first electrode of the resonator is increased, and the second electrode of the resonator is connected with the fourth electrode, so that the thickness of the second electrode of the resonator is increased, and the thickness of the electrode outside the effective area of the resonator is increased, therefore, the effective resistance of the resonator can not be increased while the resonance of the resonator is not influenced under the condition that the electrodes of the resonator are thinned.

As shown in fig. 8 and 9, an embodiment of the present invention provides a filter, including: a first resonator 8, a second resonator 9 and a third resonator 10; the second electrode of the first resonator 8 is the Input of the filter; the second electrode of the second resonator 9 is the Output end Output of the filter; the second electrode of the third resonator 10 is the ground GND of the filter; the first electrode of the first resonator 8, the first electrode of the second resonator 9 and the first electrode of the third resonator 10 are communicated with each other; the first resonator 8, the second resonator 9 and the third resonator 10 are all the resonators described above.

According to the filter provided by the embodiment of the invention, the filter is composed of the resonator, the first electrode of the resonator is connected with the third electrode, the thickness of the first electrode of the resonator is increased, the second electrode of the resonator is connected with the fourth electrode, the thickness of the second electrode of the resonator is increased, and the thickness of the electrode outside the effective area of the resonator is increased, so that the effective resistance of the resonator is not increased while the resonance of the resonator is not influenced under the condition that the electrode of the resonator is thinned. Therefore, the insertion loss of the filter composed of the resonators can be prevented from increasing without affecting the power-receiving capability and the carrier frequency of the filter.

Optionally, the third electrode of the first resonator, the third electrode of the second resonator, and the third electrode of the third resonator are in communication with each other. The first electrode and the third electrode of the first resonator, the first electrode and the third electrode of the second resonator and the first electrode and the third electrode of the third resonator are communicated with each other; the flow of the thermal power on the whole filter can be enhanced, the thermal power is effectively guided to be conducted from a hot point to a cold point on the filter, and the temperature gradient on the filter is reduced. The third electrode of the first resonator, the third electrode of the second resonator and the third electrode of the third resonator are all made of materials with high conductivity such as copper, aluminum or gold, so that the potential differences of the first resonator, the second resonator and the third resonator can be guaranteed to be uniform, and the resistivity of the first resonator, the second resonator and the third resonator can be reduced; thereby further reducing the insertion loss of the filter.

Optionally, as shown in fig. 10, notches 7 are provided on the third electrode of the first resonator 8, the third electrode of the second resonator 9, and the third electrode of the third resonator 10. In this way, it is convenient to connect the third electrode of the resonator to the first electrode of the resonator when manufacturing the filter.

Optionally, the gap 7 is less than or equal to 4 on the first resonator, the second resonator, or the third resonator.

Under the condition that the number of the notches is more than 4, the design of the resonator becomes complicated, and under the condition that the number of the notches is more than 4, the third electrode needs to be cut for more than 4 times, so that the thickening effect of the first electrode of the resonator is poor; so that the effect of reducing the resistivity of the first electrode is not good.

Referring to fig. 11, fig. 11 is a graph showing the insertion loss of filters with different thickness of electrodes as a function of frequency, wherein the electrode thickness of the filter corresponding to curve a is greater than that of the filter corresponding to curve b; as can be seen from fig. 11, when the frequency is 2.5 to 2.7GHz, the insertion loss of the curve a is smaller than that of the curve b, and therefore, the insertion loss of the filter decreases as the thickness of the electrode increases. Therefore, in the embodiment of the invention, the first electrode of the resonator is connected with the third electrode, the thickness of the first electrode of the resonator is increased, the second electrode of the resonator is connected with the fourth electrode, and the thickness of the second electrode of the resonator is increased, so that the thickness of the electrode outside the effective area of the resonator is increased, and therefore, the insertion loss of the filter formed by the resonator can not be increased under the condition of not influencing the power bearing capacity and the carrier frequency of the filter; and even reduces the insertion loss of a filter formed of the resonators.

The above description and drawings sufficiently illustrate embodiments of the invention to enable those skilled in the art to practice them. Other embodiments may include structural and other changes. The examples merely typify possible variations. Individual components and functions are optional unless explicitly required, and the sequence of operations may vary. Portions and features of some embodiments may be included in or substituted for those of others. The embodiments of the present invention are not limited to the structures that have been described above and shown in the drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.