Single-chip high-integration-level crystal filter
By integrating multiple pairs of resonant units on a single wafer and employing an asymmetric electrode design and a cross-sectional topology, the problem of miniaturization of integrated crystal filters has been solved, resulting in a high-performance and compact crystal filter suitable for mass production.
Patent Information
- Application Number
- CN202512004604.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-29
- Publication Date
- 2026-02-24
AI Technical Summary
In the existing technology, integrated crystal filters are difficult to miniaturize while achieving high performance. Conventional solutions increase the size of the filter by connecting it in series, which limits its application in miniaturized devices.
Multiple pairs of resonant units are integrated on a single chip. An asymmetric electrode design and a horizontal and vertical topology are adopted. The arrangement of the resonant units and the proportion of the electrode pattern are rationally planned to form multiple sets of resonant units.
Without increasing the size, the stopband suppression performance is significantly improved, ensuring the filter's high performance and compact size, making it suitable for mass production.
Smart Images
Figure CN121567092A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of crystal filter design technology, specifically relating to a single-chip high-integration crystal filter. Background Technology
[0002] A crystal filter is an electronic filter that uses a crystal as a capacitor or inductor. It features high frequency selectivity, strong stopband suppression, and excellent anti-interference capabilities, making it widely used in aerospace and other fields. Based on circuit structure, crystal filters can be divided into discrete and integrated types. An integrated crystal filter integrates two pairs of electrodes on opposite sides of a single crystal wafer, thus realizing two pairs of resonant units on the same wafer. It is based on the piezoelectric effect: an input electrical signal excites the crystal's mechanical vibration mode (such as a thickness shear mode), and by using electrode mass loading or geometry to restrict the propagation of vibrational energy in a specific area, unwanted stray modes are suppressed, allowing only the target frequency energy to pass. Different resonant units can generate energy resonance in a specific frequency band through acoustic coupling, thereby achieving frequency filtering. Integrated crystal filters are typically packaged independently in dedicated housings, such as… Figure 1 As shown.
[0003] As system architectures continue to evolve towards miniaturization and integration, the demand for crystal filters that maintain high performance while achieving smaller size is increasing. Currently, the conventional solution for achieving high-performance crystal filters typically involves connecting two integrated crystal filters in series using an external circuit, such as... Figure 2 As shown, this method aims to meet performance requirements such as high stopband suppression. However, it increases the overall size of the filter, thus limiting its practical application. Summary of the Invention
[0004] To address the aforementioned problems, this invention provides a single-chip high-integration crystal filter, which integrates multiple pairs of resonant units on a single chip, thereby ensuring high performance of the device without increasing its size and making it suitable for mass production.
[0005] The specific solution includes a chip, as well as an input crystal resonator unit group and an output crystal resonator unit group disposed on the chip;
[0006] The input crystal resonant unit group includes rectangular electrodes A and B disposed on the upper surface of the wafer, and rectangular electrode C disposed on the lower surface of the wafer; wherein, rectangular electrodes A and C and the wafer form a first pair of resonant units, and rectangular electrodes B and C and the wafer form a second pair of resonant units.
[0007] The output crystal resonant unit group includes rectangular electrodes D and E disposed on the upper surface of the wafer, and rectangular electrode F disposed on the lower surface of the wafer; wherein, rectangular electrodes D and F together with the wafer form a third pair of resonant units, and rectangular electrodes E and F together with the wafer form a fourth pair of resonant units.
[0008] The input signal passes through the first pair of resonant units, is coupled to the second pair of resonant units, then enters the third pair of resonant units in series, is coupled to the fourth pair of resonant units, and finally reaches the output.
[0009] The beneficial effects of this invention are:
[0010] This invention relates to a highly integrated monocrystalline crystal filter that employs an asymmetric electrode design and a side-by-side topology. By integrating multiple electrode pairs on a single wafer to form multiple resonant units, and by rationally planning the arrangement of the resonant units and the aspect ratio of each electrode pattern, the stopband suppression performance is significantly improved. This structure ensures high overall performance while maintaining a compact filter size. Attached Figure Description
[0011] Figure 1 A schematic diagram of an integrated crystal filter electrode design;
[0012] Figure 2 A schematic diagram of a circuit for two integrated crystal filters connected in series.
[0013] Figure 3 This is a schematic diagram of the electrode design for the monocrystalline high-integration crystal filter of the present invention;
[0014] Figure 4 This is a schematic diagram of the application circuit for the single-chip high-integration crystal filter of the present invention;
[0015] Figure 5 The image shows the simulation response curve of a single-chip high-integration crystal filter according to an embodiment of the present invention. Detailed Implementation
[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0017] Some embodiments of the present invention provide a single-chip high-integration crystal filter, such as... Figures 3-4 As shown, it includes a wafer, and an input crystal resonator group and an output crystal resonator group disposed on the wafer.
[0018] The input crystal resonant unit group includes rectangular electrodes A and B disposed on the upper surface of the wafer, and rectangular electrode C disposed on the lower surface of the wafer; wherein, rectangular electrodes A and C and the wafer form a first pair of resonant units, and rectangular electrodes B and C and the wafer form a second pair of resonant units.
[0019] The output crystal resonant unit group includes rectangular electrodes D and E disposed on the upper surface of the wafer, and rectangular electrode F disposed on the lower surface of the wafer; wherein, rectangular electrodes D and F together with the wafer form a third pair of resonant units, and rectangular electrodes E and F together with the wafer form a fourth pair of resonant units.
[0020] The input signal is transmitted from the first pair of resonant units in the input crystal resonant unit group to the second pair of resonant units through coupling, then in series into the third pair of resonant units in the output crystal resonant unit group, and then transmitted to the fourth pair of resonant units through coupling, and finally to the output.
[0021] Specifically, the electrical performance parameters of the first pair of resonant units and the second pair of resonant units should be the same, and the electrical performance parameters of the third pair of resonant units and the fourth pair of resonant units should be the same.
[0022] Specifically, rectangular electrodes A through F are all rectangular metal electrodes.
[0023] In some embodiments, rectangular electrodes A and B are placed parallel to each other at the intersection of the midpoint of the width direction and the quarter point of the length direction on the upper surface of the wafer, and a rectangular electrode C is disposed at a corresponding position on the lower surface; a gap exists between rectangular electrodes A and B. Specifically, as... Figure 3 As shown, the width direction of the wafer's upper surface refers to the direction from the bottom edge of the wafer to the top edge of the wafer, and the length direction of the wafer's upper surface refers to the direction from the left edge of the wafer to the right edge of the wafer.
[0024] Specifically, an electrode transmission line is drawn from rectangular electrode A and extends to the upper left corner of the upper surface of the wafer to form an input connection point; an electrode transmission line is drawn from rectangular electrode B and extends to the center of the lower side of the upper surface of the wafer to form an output connection point; an electrode transmission line is drawn from rectangular electrode C and extends to the lower left corner of the lower surface of the wafer to form a ground connection point.
[0025] In some embodiments, rectangular electrode A and rectangular electrode B have the same geometric dimensions; the width of rectangular electrode C is the same as the length of rectangular electrode A, and the length of rectangular electrode C is twice the width of rectangular electrode A plus the distance between rectangular electrode A and rectangular electrode B.
[0026] Specifically, such as Figure 4As shown, the space occupied by rectangular electrode C completely covers rectangular electrode A and rectangular electrode B.
[0027] In some embodiments, rectangular electrodes D and E are placed in parallel at the intersection of the midpoint of the width direction and the three-quarters point of the length direction on the upper surface of the wafer, and a rectangular electrode F is disposed at a corresponding position on the lower surface; there is a gap between rectangular electrodes D and rectangular electrodes E.
[0028] An electrode transmission line is drawn from rectangular electrode D and extends to the center of the upper side of the wafer surface to form an input connection point; an electrode transmission line is drawn from rectangular electrode E and extends to the lower right corner of the wafer surface to form an output connection point; an electrode transmission line is drawn from rectangular electrode F and extends to the lower right corner of the wafer surface to form a ground connection point.
[0029] In some embodiments, rectangular electrode D and rectangular electrode E have the same geometric dimensions; the width of rectangular electrode F is the same as the length of rectangular electrode D, and the length of rectangular electrode F is twice the width of rectangular electrode D plus the spacing between rectangular electrode D and rectangular electrode E.
[0030] Specifically, such as Figure 4 As shown, the space occupied by rectangular electrode F completely covers rectangular electrode D and rectangular electrode E.
[0031] In some embodiments, the length of rectangular electrode A is 1.1 to 1.3 times the length of rectangular electrode D, the width of rectangular electrode D is 1.1 to 1.3 times the width of rectangular electrode A, and the spacing between rectangular electrode A and rectangular electrode B is equal to the spacing between rectangular electrode D and rectangular electrode E.
[0032] In some embodiments, rectangular electrode A is connected to the input terminal through the input terminal connection point formed by the electrode transmission line; rectangular electrode B and rectangular electrode D are coupled through the output terminal connection point formed by the electrode transmission line and the input terminal connection point formed by the electrode transmission line, respectively, by a grounding capacitor; rectangular electrode E is connected to the output terminal through the output terminal connection point formed by the electrode transmission line; rectangular electrode C and rectangular electrode F are grounded through the grounding terminal connection point formed by the electrode transmission line.
[0033] This invention is applicable to the design of crystal filters with various frequencies and bandwidths, enabling the integration of four pairs of resonant units on a single crystal. By adopting a "side-by-side" layout and configuring differentiated electrode sizes for each resonant unit, the high performance of the filter is ensured while maintaining a compact device size. Figure 5 The simulation response curve of a highly integrated single-chip crystal filter is shown. Based on this method, a crystal filter with a center frequency of 21.4MHz and a bandwidth of 70kHz was successfully designed. After optimization, its stopband rejection can reach about 72dB.
[0034] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "rotation," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0035] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A single-chip high-integration crystal filter, characterized in that, Includes a wafer, and an input crystal resonator unit group and an output crystal resonator unit group disposed on the wafer; The input crystal resonant unit group includes rectangular electrodes A and B disposed on the upper surface of the wafer, and rectangular electrode C disposed on the lower surface of the wafer; wherein, rectangular electrodes A and C and the wafer form a first pair of resonant units, and rectangular electrodes B and C and the wafer form a second pair of resonant units. The output crystal resonant unit group includes rectangular electrodes D and E disposed on the upper surface of the wafer, and rectangular electrode F disposed on the lower surface of the wafer; wherein, rectangular electrodes D and F together with the wafer form a third pair of resonant units, and rectangular electrodes E and F together with the wafer form a fourth pair of resonant units. The input signal passes through the first pair of resonant units, is coupled to the second pair of resonant units, then enters the third pair of resonant units in series, is coupled to the fourth pair of resonant units, and finally reaches the output.
2. The monocrystalline high-integration crystal filter according to claim 1, characterized in that, At the intersection of the midpoint of the width direction and the quarter point of the length direction on the upper surface of the wafer, rectangular electrodes A and B are placed in parallel, and rectangular electrode C is placed at the corresponding position on the lower surface; there is a gap between rectangular electrodes A and B. An electrode transmission line is drawn from rectangular electrode A and extends to the upper left corner of the upper surface of the wafer to form an input connection point; an electrode transmission line is drawn from rectangular electrode B and extends to the center of the lower side of the upper surface of the wafer to form an output connection point; an electrode transmission line is drawn from rectangular electrode C and extends to the lower left corner of the lower surface of the wafer to form a ground connection point.
3. A single-chip high-integration crystal filter according to claim 2, characterized in that, Rectangular electrode A and rectangular electrode B have the same geometric dimensions; the width of rectangular electrode C is the same as the length of rectangular electrode A, and the length of rectangular electrode C is twice the width of rectangular electrode A plus the distance between rectangular electrode A and rectangular electrode B.
4. A single-chip high-integration crystal filter according to claim 1, characterized in that, At the intersection of the midpoint of the width direction and the three-quarters point of the length direction on the upper surface of the wafer, rectangular electrodes D and E are placed in parallel, and a rectangular electrode F is set at the corresponding position on the lower surface; there is a gap between rectangular electrodes D and E. An electrode transmission line is drawn from rectangular electrode D and extends to the center of the upper side of the wafer surface to form an input connection point; an electrode transmission line is drawn from rectangular electrode E and extends to the lower right corner of the wafer surface to form an output connection point; an electrode transmission line is drawn from rectangular electrode F and extends to the lower right corner of the wafer surface to form a ground connection point.
5. A single-chip high-integration crystal filter according to claim 4, characterized in that, Rectangular electrode D and rectangular electrode E have the same geometric dimensions; the width of rectangular electrode F is the same as the length of rectangular electrode D, and the length of rectangular electrode F is twice the width of rectangular electrode D plus the distance between rectangular electrode D and rectangular electrode E.
6. A single-chip high-integration crystal filter according to claim 1, characterized in that, The length of rectangular electrode A is 1.1 to 1.3 times the length of rectangular electrode D, the width of rectangular electrode D is 1.1 to 1.3 times the width of rectangular electrode A, and the spacing between rectangular electrodes A and B is equal to the spacing between rectangular electrodes D and E.
7. A single-chip high-integration crystal filter according to claim 1, characterized in that, The output terminal connection point of rectangular electrode B and the input terminal connection point of rectangular electrode D are coupled through a grounding capacitor; the grounding terminal connection point of rectangular electrode C and the grounding terminal connection point of rectangular electrode F are grounded through the electrode transmission line.