CN118054767A

CN118054767A - Filter, radio frequency system and electronic equipment

Info

Publication number: CN118054767A
Application number: CN202211429418.5A
Authority: CN
Inventors: 周彦昭
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2022-11-15
Filing date: 2022-11-15
Publication date: 2024-05-17

Abstract

A filter, a radio frequency system and an electronic device. The filter includes: a package substrate including a first side and a second side opposite the first side; a low temperature co-fired ceramic resonator coupled to a first side of the package substrate; an acoustic resonator is coupled to the first side or the second side of the package substrate and is cascade coupled with the low temperature co-fired ceramic resonator. Through cascading, the common advantages of the low-temperature co-fired ceramic resonator and the acoustic resonator can be fully utilized, the bandwidth of the acoustic filter is widened, the cascaded mixed mode filter is enabled to achieve larger bandwidth and high quality factors, meanwhile, the miniaturization of the filter device is achieved, and the device competitiveness is improved.

Description

Filter, radio frequency system and electronic equipment

Technical Field

The present disclosure relates generally to the field of communications. More particularly, the present disclosure relates to a filter, a radio frequency system, and an electronic device.

Background

In the field of communications, a filter is an important component that can be used in a signal transmission path to filter a signal in transmission, thereby selecting a signal of a suitable frequency. Filters have wide application, for example, in various mobile devices, in-vehicle communication devices, and the like. The filter is one of the core components in the current radio frequency module.

Conventional filters are narrow-band devices, and have reached the requirement of near-end high rejection. New application scenes such as Wifi6E/Wifi7/UWB have put forward broadband appeal to the filter. On the one hand, a filter such as low-temperature co-fired ceramic (Low Temperature Co-FIRED CERAMIC, LTCC) or printed circuit board (Printed Circuit Board, PCB) can realize wider bandwidth, but due to lower Q value, high suppression cannot be generated on the near-band of the filter, and the coexistence requirement of honeycomb and WIFI is difficult to meet. On the other hand, although an acoustic filter can achieve a high Q value, it cannot achieve a wide bandwidth due to the acoustic wave theory.

A filter has been proposed that utilizes an acoustic resonator and an integrated passive device (INTEGRATED PASSIVE DEVICE, IPD) resonator. In such a filter, the space for improvement of Q-value performance is very limited due to the short-plate effect of the filter. How to further improve the performance of the filter creates a great challenge for the designer.

Disclosure of Invention

In order to sufficiently achieve high performance of the filter, embodiments of the present disclosure provide a solution for chips and electronic devices.

In a first aspect of the present disclosure, a filter is provided. The filter includes: a package substrate including a first side and a second side opposite the first side; a low temperature co-fired ceramic resonator coupled to the first side of the package substrate; and an acoustic resonator coupled to the first side or the second side of the package substrate and coupled in cascade with the low temperature co-fired ceramic resonator.

According to the embodiment of the disclosure, the common advantages of the low-temperature co-fired ceramic resonator and the acoustic resonator can be fully utilized, so that the filter has higher performance, meanwhile, the miniaturization of the device of the filter is realized, and the device competitiveness is improved.

In some embodiments, the low temperature co-fired ceramic resonator is coupled to the first side of the package substrate via bumps or bond wires. In some embodiments, the low temperature co-fired ceramic resonator is directly coupled to the first side of the package substrate. In this way, a diversified coupling of the low temperature co-fired ceramic resonator and the package substrate can be provided.

In some embodiments, the acoustic resonator is coupled to the first side or the second side of the package substrate via bumps or bonding wires. In some embodiments, the acoustic resonator is directly coupled to the first side or the second side of the package substrate. In this way, a diversified coupling of the acoustic resonator and the package substrate can be provided.

In some embodiments, the low temperature co-fired ceramic resonator and the acoustic resonator are coupled to an underside of the package substrate. In this way, flip-chip mounting of the acoustic resonator can be achieved.

In some embodiments, the low temperature co-fired ceramic resonator comprises one or more of a transverse magnetic wave resonator, a transverse electric wave resonator, a transverse electromagnetic wave resonator, a dual mode resonator. In this way, various types of low temperature co-fired ceramic resonators may be employed to accommodate different usage scenarios.

In some embodiments, the low temperature co-fired ceramic resonator comprises: an input and an output; and a plurality of capacitors coupled in series between the input terminal and the output terminal, with one or more first coupling points therebetween; and one or more resonance units respectively coupled between the one or more first coupling points and the common coupling end. In this way, by flexibly adjusting the topology of the low temperature co-fired ceramic resonator in the filter, the scheme of the application can meet more design requirements while realizing high Q value.

In some embodiments, each resonant cell includes a first layer, a second layer, and a third layer disposed in a stacked order, the first layer and the third layer having a dielectric constant lower than a dielectric constant of the second layer. In this way, electromagnetic resonance of the TM mode can be achieved while making the overall structure of the resonance unit more compact and while improving the Q value of the resonance unit.

In some embodiments, each resonant cell includes an equivalent capacitor and an equivalent inductance coupled in parallel.

In some embodiments, the acoustic resonator comprises one or more of a bulk acoustic wave resonator, an HBAR resonator, XBAW resonator, an XBAR resonator, a surface acoustic wave resonator. In this way, various types of acoustic resonators may be employed to accommodate different usage scenarios.

In some embodiments, the acoustic resonator comprises: a plurality of first series resonators coupled in series with one or more second coupling points therebetween; and one or more first parallel resonators coupled between the one or more second coupling points and the common coupling end, respectively. In this way, the acoustic resonator can be made to adopt a more flexible topology to accommodate more usage scenarios.

In some embodiments, the common coupling is a ground. In some embodiments, one or more inductors are coupled between the common coupling terminal and the ground terminal. In this way, the acoustic resonator can be made to adopt a more flexible topology to accommodate more usage scenarios.

In some embodiments, the acoustic resonator comprises: a plurality of second series resonators coupled to each other in series and coupled to the plurality of capacitors; and a plurality of third series resonators coupled in series with each other and coupled to the common coupling terminal.

In some embodiments, one of the plurality of second series resonators includes: a first end coupled to the low temperature co-fired ceramic resonator and a second end opposite the first end; one of the plurality of third series resonators includes: a third terminal coupled to the low temperature co-fired ceramic resonator and a fourth terminal opposite the third terminal; the first end is coupled to the fourth end via a fourth series resonator, and the second end is coupled to the third end via a fifth series resonator. In this way, the user can employ the corresponding circuit topology according to different index requirements of various products.

In some embodiments, one or more third coupling points are arranged among the second series resonators, one or more fourth coupling points are arranged among the third series resonators, and the second parallel resonators are respectively coupled between the third coupling points and the fourth coupling points. In this way, by flexibly adjusting the topology of the acoustic resonators in the filter, the filter of the present application can be made to meet more design requirements while achieving high Q values.

In some embodiments, there are one or more fifth coupling points between the plurality of second series resonators, one or more sixth coupling points between the plurality of third series resonators, a plurality of third parallel resonators respectively coupled between the fifth coupling point and the sixth coupling point, and a resistor coupled between the plurality of third parallel resonators. In this way, the filter has good applicability and expansibility so that the user can use and expand the scheme of the present application according to the actual scenario.

In some embodiments, each first series resonator body or each first parallel resonator body comprises: a substrate; a piezoelectric film disposed over the substrate; a signal terminal disposed above the piezoelectric film; and a ground terminal disposed over the piezoelectric film or between the piezoelectric film and the substrate. In this way, by employing the higher harmonic bulk acoustic wave resonator, a resonance frequency response of a high Q value can be brought about.

In some embodiments, each second series resonator body or each second parallel resonator body comprises: a substrate; a piezoelectric film disposed over the substrate; a signal terminal disposed above the piezoelectric film; and a ground terminal disposed over the piezoelectric film or between the piezoelectric film and the substrate. In this way, by employing the higher harmonic bulk acoustic wave resonator, a resonance frequency response of a high Q value can be brought about.

In some embodiments, a bottom electrode, a first reflective layer, and a second reflective layer are disposed between the substrate and the piezoelectric film at a time, the bottom electrode being coupled to the piezoelectric film, the second reflective layer being coupled to the substrate. In some embodiments, the first reflective layer is made of a first material, the second reflective layer is made of a second material, and the acoustic impedance of the first material is higher than the acoustic impedance of the second material. In this way, the acoustic resonator can be implemented with a material that is stable and reliable, ensuring high performance of the filter.

In some embodiments, the substrate comprises one or more of a low temperature co-fired ceramic substrate, a printed circuit board substrate, a glass via substrate. In this way, various types of package substrates may be employed to accommodate different usage scenarios.

In a second aspect of the present disclosure, a radio frequency system is provided. The radio frequency system comprises a filter and a radio frequency circuit according to the first aspect of the present disclosure.

In a third aspect of the present disclosure, an electronic device is provided. The electronic device comprises a processor, a circuit board, and a filter according to the first aspect of the present disclosure, the filter and the processor being disposed on the circuit board.

These and other aspects of the disclosure will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

Drawings

The above and other features, advantages and aspects of embodiments of the present disclosure will become more apparent by reference to the following detailed description when taken in conjunction with the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements. The drawings are not necessarily to scale, wherein:

FIG. 1 illustrates a schematic diagram of a filter according to some embodiments of the present disclosure;

FIG. 2 shows a schematic diagram of a filter according to further embodiments of the present disclosure;

FIG. 3 illustrates a schematic top view in a filter showing cascading traces between an acoustic resonator and a low-temperature co-fired ceramic resonator according to an embodiment of the present disclosure;

Fig. 4 illustrates a schematic topology of a filter according to some embodiments of the present disclosure;

fig. 5 shows a schematic topology of a filter according to further embodiments of the present disclosure;

fig. 6 shows a schematic topology of a filter according to further embodiments of the present disclosure;

FIG. 7 illustrates one possible implementation of a resonant cell of a low temperature co-fired ceramic resonator in a filter according to some embodiments of the present disclosure;

fig. 8a and 8b show schematic perspective views of some possible implementations of the resonator body of an acoustic resonator in a filter according to some embodiments of the present disclosure; and

Fig. 9 illustrates a schematic front view of some possible implementations of the resonator body of an acoustic resonator in a filter, according to some embodiments of the present disclosure.

Detailed Description

Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While certain embodiments of the present disclosure have been shown in the accompanying drawings, it is to be understood that the present disclosure may be embodied in various forms and should not be construed as limited to the embodiments set forth herein, but are provided to provide a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are for illustration purposes only and are not intended to limit the scope of the present disclosure.

In describing embodiments of the present disclosure, the term "comprising" and its like should be taken to be open-ended, i.e., including, but not limited to. The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first," "second," and the like, may refer to different or the same object. Other explicit and implicit definitions are also possible below. Furthermore, the terms "connected," "coupled," and the like may refer to the association of related elements in different forms, including both mechanically and electrically, magnetically, thermally, etc.; including directly, as well as indirectly via intermediate components.

As mentioned above, filters are an important component in communication systems. In filters, the Q value is typically used to measure the quality factor of the filter, which describes the ability of the filter to separate adjacent frequency components in a signal. In a two-stage cascaded filter, the Q value of the overall filter satisfies the following formula:

Wherein Q1 and Q2 represent the Q values of the resonators constituting the filter, respectively. As can be seen from the above formula, the Q of the two-stage cascaded filter is smaller than that of each individual resonator, i.e. the barrel effect is met. For example, in a filter consisting of an acoustic resonator and an integrated passive device resonator, the Q of the acoustic resonator may be as high as 1500, but the Q of the integrated passive device resonator is only 130, and thus the final Q of the filter consisting of these two resonators is only 119. Such a Q value is too low to meet the filter requirements of 5G communications.

Therefore, the embodiments of the present disclosure provide a filter capable of realizing a high Q value, which uses a low-temperature co-fired ceramic resonator and an acoustic resonator to form the filter, fully uses good characteristics of the high Q value of the low-temperature co-fired ceramic resonator, and finally realizes an integrated filter by packaging the low-temperature co-fired ceramic resonator and the acoustic resonator on the same package substrate, thereby realizing miniaturization and high performance. Compared with the existing mode of using an acoustic resonator and an integrated passive device resonator to form the filter, the Q value of the low-temperature co-fired ceramic resonator is obviously higher than that of the integrated passive device resonator, and the Q value of the finally obtained filter can be obviously improved.

Some exemplary implementations of the present disclosure will be described below with reference to fig. 1-3, where fig. 1 shows a schematic diagram of a filter 10 according to some embodiments of the present application.

As shown in fig. 1, the filter 10 generally includes a package substrate 12 and an acoustic resonator 14 and a low temperature co-fired ceramic resonator 16 located on the package substrate 12. The package substrate 12 includes oppositely disposed first sides 121 (e.g., upper sides) and second sides 122 (e.g., lower sides). As shown, the acoustic resonator 14 and the low temperature co-fired ceramic resonator 16 are disposed on the same side of the package substrate 12, i.e., the first side 121.

Fig. 2 shows a schematic diagram of a filter 20 according to further embodiments of the application. Similar to fig. 1, the filter 20 of fig. 2 generally includes a package substrate 22 and an acoustic resonator 24 and a low temperature co-fired ceramic resonator 26 coupled to the package substrate 22. The package substrate 22 includes oppositely disposed first sides 221 (e.g., upper sides) and second sides 222 (e.g., lower sides). As shown in fig. 2, the acoustic resonator 14 and the low temperature co-fired ceramic resonator 16 are disposed on the same side of the package substrate 12, i.e., the second side 222. In this way, the acoustic resonator 24 and the low temperature co-fired ceramic resonator 26 can be flip-chip mounted on the package substrate 20, thereby being suitable for more scenarios.

It should be appreciated that the acoustic resonator and the low temperature co-fired ceramic resonator may be disposed on different sides of the package substrate. For example, in some embodiments, an acoustic resonator may be coupled to a first side of a package substrate, while a low temperature co-fired ceramic resonator may be coupled to a second side of the package substrate. In other embodiments, the low temperature co-fired ceramic resonator may be coupled to a first side of the package substrate and the acoustic resonator may be coupled to a second side of the package substrate.

Referring back to fig. 1, the acoustic resonator 14 may be coupled to the package substrate 12 via bumps 13. In the embodiment shown in fig. 2, the acoustic resonator 24 may be coupled to the package substrate 22 via bond wires 23. Of course, it is understood that these are merely illustrative, and that in other embodiments the acoustic resonator may also be coupled to the package substrate via other means. In other embodiments, the acoustic resonator may be directly coupled to the package substrate. It should be understood that the manner in which the acoustic resonator is coupled to the package substrate is not limited by the disclosed embodiments.

Referring back to fig. 1, the low temperature co-fired ceramic resonator 16 may be directly coupled with the package substrate 12. In the embodiment shown in fig. 2, the low temperature co-fired ceramic resonator 26 may be coupled to the package substrate 22 via bond wires 25. Of course, it is understood that these are merely illustrative, and that in other embodiments the acoustic resonator may also be coupled to the package substrate via other means. For example, in other embodiments, the low temperature co-fired ceramic resonator may be coupled to the package substrate via bumps. It should be understood that the manner in which the low temperature co-fired ceramic resonator is coupled to the package substrate is not limited by the disclosed embodiments.

In some embodiments, the acoustic resonators 14, 24 and the low temperature co-fired ceramic resonators 16, 26 may be coupled using any known or future developed means, for example, cascading of the acoustic resonators 14, 24 and the low temperature co-fired ceramic resonators may be accomplished via transmission lines internal to the package substrates 12, 22.

According to the embodiment of the disclosure, the low-temperature co-fired ceramic resonator and the acoustic resonator are coupled in a cascade manner through the packaging substrate and various coupling modes, so that the normal operation of the filter is ensured.

Fig. 3 shows a schematic top view in a filter 30 showing cascading traces between an acoustic resonator 34 and a low-temperature co-fired ceramic resonator 36 according to an embodiment of the present disclosure. As shown in fig. 3, the acoustic resonator 34 is electrically connected by bonding wires 33, and the low-temperature co-fired ceramic resonator 36 is electrically connected by transmission lines 35 on the package substrate. As shown in fig. 3, the bond wire 33 and the transmission line 35 may be commonly coupled to the input terminal 31. Bond wire 33 and transmission line 35 may also be commonly coupled to output 32 to achieve a complete wired connection. In some embodiments, such a transmission line 35 is made of metal. In a further embodiment, such metal may be copper.

In some embodiments, the low temperature co-fired ceramic resonator may be one or more of a transverse magnetic wave (TRANSVERSE MAGNETIC, TM) resonator, a transverse electric wave (TRANSVERSE ELECTRIC, TE) resonator, a transverse electromagnetic wave (TRANSVERSE ELECTROMAGNETIC, TEM) resonator. In other embodiments, the low temperature co-fired ceramic resonator may also be a dual mode resonator. In this way, various types of low temperature co-fired ceramic resonators may be used to implement filters according to the present disclosure.

In some embodiments, the acoustic resonator may be one or more of a bulk acoustic wave (Bulk Acoustic Wave, BAW) resonator, a higher harmonic bulk acoustic wave (High-overtone Bulk Acoustic Resonator, HBAR) resonator, a XBAW resonator, an XBAR resonator, a surface acoustic wave (Surface Acoustic Wave, SAW) resonator. In further embodiments, the surface acoustic wave resonator may be a temperature compensated (Temperature Compensated, TC) surface acoustic wave resonator or a super high performance (Incredible High Performance, IHP) surface acoustic wave resonator. In this way, filters according to the present disclosure may be implemented using various types of acoustic resonators.

In some embodiments, the package substrate may be one or more of a low temperature co-fired ceramic (LTCC) substrate, a printed circuit board substrate, a glass via (Through Glass Via, TGV) substrate. In this way, the filter according to the present disclosure may be implemented using various types of package substrates.

Some exemplary topology circuit configurations of filters according to embodiments of the present disclosure are described below in conjunction with fig. 4-6. Referring first to fig. 4, as shown in fig. 4, the filter 40 generally includes an acoustic resonator 44 and a low temperature co-fired ceramic resonator 46 coupled together, with the package substrate not shown in fig. 4 for simplicity.

The topology of the low temperature co-fired ceramic resonator 46 in the filter 40 is described below with reference to fig. 4. As shown, the low temperature co-fired ceramic resonator 46 includes an input terminal IN and an output terminal OUT, and a plurality of capacitors 461 coupled between the input terminal IN and the output terminal OUT. These capacitors 461 are coupled in series, and a first coupling point P1 is formed between two adjacent capacitors 461. Four capacitors 461 and three first coupling points P1 therebetween are shown in fig. 4. It should be understood that this is merely illustrative, and in other embodiments, more or fewer capacitors 461 may be provided with first coupling point P1 therebetween, the particular number not being limited by embodiments of the present disclosure. With continued reference to fig. 4, the low temperature co-fired ceramic resonator 46 may further include one or more resonant cells 462, with the resonant cells 462 being coupled between the first coupling point P1 and the common coupling end REF, respectively. As shown in fig. 4, an equivalent capacitor 463 and an equivalent inductance 464 coupled in parallel are included in each resonant cell 462.

Fig. 7 illustrates one possible implementation of a resonating unit 700 of a low-temperature co-fired ceramic resonator in a filter according to embodiments of the present disclosure, and resonating unit 462 in fig. 4 may be fabricated using resonating unit 700 in fig. 7. As shown in fig. 7, the resonance unit 700 may include a first layer 701, a second layer 702, and a third layer 703 stacked in this order, wherein the dielectric constant of the first layer 701 and the third layer 703 is lower than that of the second layer 702. Through the laminated structure, electromagnetic resonance of the TM mode can be realized, and meanwhile, the whole structure of the resonance unit 700 is smaller and more compact, so that the laminated structure is suitable for various different use scenes.

In some embodiments, the first layer 701 and the third layer 703 may be made of the same ceramic material, whereby the entire resonant unit 700 will be made of both ceramic materials. In other embodiments, the first layer 701 and the third layer 703 may be made of different materials, whereby the materials of the first layer 701, the second layer 702 and the third layer 703 are all different, which will result in the entire resonator unit 700 being made of three different ceramic materials. It should be noted that embodiments of the present disclosure are not limited to these materials, as long as they are capable of providing predetermined dielectric constants to the layers of the resonant cell 700. In the manner shown in fig. 7, TM mode resonance can be achieved in the three-dimensional structural cavity by embedding two or more ceramic materials and a material of high dielectric constant in a material of low dielectric constant. Compared with the traditional mode of using a metal cavity, the TM resonant mode formed by the method does not need a traditional laminated inductor structure, so that the quality factor of the low-temperature co-fired ceramic device can be greatly improved.

The topology of the acoustic resonator 44 in the filter 40 is described below with reference back to fig. 4. As shown in fig. 4, the acoustic resonator 44 includes a plurality of first series resonant bodies 441, the first series resonant bodies 441 being coupled in series, and one or more second coupling points P2 being provided between the first series resonant bodies 441. Six first series resonators 441 are shown in fig. 4, and four second coupling points P2 are formed. It should be understood that this is merely illustrative. In other embodiments, more or fewer first series resonators 441 and second coupling points P2 therebetween may be provided, and the specific number may be adjusted accordingly as desired, and such embodiments fall within the scope of the present disclosure. Furthermore, in the embodiment shown in fig. 4, there are one or two first series resonators 441 between two adjacent second coupling points P2, which is also merely illustrative. As will be appreciated by those skilled in the art, since the second coupling point P2 may exist between any two first series resonators 441, any number of first series resonators 441 may exist between adjacent second coupling points P2 according to different arrangements. The embodiments of the present disclosure are not particularly limited thereto.

As shown in fig. 4, the acoustic resonator 44 may also include one or more first parallel resonators 442. The first parallel resonators 442 are respectively coupled between one or more second coupling points P2 and a common coupling end REF. In fig. 4 four first parallel resonators 442 are shown, the number of which corresponds to the number of second coupling points P2. It should be appreciated that this is merely exemplary, and that in other embodiments, other numbers of branches may be provided to provide the first parallel resonator 442, depending on the actual design requirements. It should also be appreciated that while only the first parallel resonator 442 is shown in fig. 4 as being disposed between the second coupling point P2 and the common coupling end REF, this is also merely illustrative. In some embodiments, two, three or even more first parallel resonators 442 may be provided between the second coupling point P2 and the common coupling end REF. In other embodiments, the first parallel resonator 442 may not be disposed between the second coupling point P2 and the common coupling end REF. These embodiments fall within the scope of embodiments of the present application. It should also be noted that in some embodiments, the plurality of first series resonant bodies 441 in fig. 4 may have different resonant cell sizes from each other, thereby realizing different resonant frequency points from each other. Similarly, the plurality of first parallel resonators 442 may have different resonance unit sizes from each other so as to realize different resonance frequency points from each other. In some embodiments, as shown in fig. 4, the common coupling terminal REF may be a ground terminal.

According to an embodiment of the present disclosure, the number and connection manner of various types of devices in the filter 40 in fig. 4 may be adjusted based on different design requirements, thereby achieving a desired design effect. Embodiments according to the present disclosure have good scalability.

Some possible implementations of the resonator bodies of the acoustic resonators in the filter according to embodiments of the disclosure are described below with reference to fig. 8a to 9, both the first series resonator body 441 and the first parallel resonator body 442 in fig. 4 may be made with the resonator body 800 in fig. 8a or 8b, or the resonator body 900 in fig. 9.

As shown in fig. 8a, a schematic perspective view of one possible implementation of a resonator body 800 is shown. As shown, the resonator body 800 is generally in a laminated structure, and includes a substrate 801 and a piezoelectric film 802 disposed over the substrate 801. The resonator body 800 may further include a signal terminal 803 and a ground terminal 804 on the piezoelectric film 802, thereby realizing connection of the resonator body 800 with other resonator bodies 800. As shown in fig. 8a, the signal terminal 803 and the ground terminal 804 may be juxtaposed on the same layer above the piezoelectric film 802.

Fig. 8b shows a schematic perspective view of another possible implementation of the resonator body 800. As shown, the resonator body 800 is generally in a laminated structure, and includes a substrate 801 and a piezoelectric film 802 disposed over the substrate 801. The resonator body 800 may further comprise a signal terminal 803 on the piezoelectric film 802 and a ground terminal 804 between the piezoelectric film 802 and the substrate 801, thereby enabling connection of the resonator body 800 to other resonator bodies 800. As shown in fig. 8b, the signal terminal 803 and the ground terminal 804 are not located at the same layer.

The resonator body in fig. 8a and 8b is an HBAR resonator, which is a device that resonates based on bulk acoustic waves. The HBAR is a device formed by preparing a metal electrode-piezoelectric film-metal electrode sandwich structure transducer on a low-loss substrate, and can generate a plurality of high-Q resonance points in a radio frequency band. In some embodiments, when the HBAR resonator is operated, the piezoelectric film stretches in the thickness direction under the action of an external electric field, and acoustic wave energy excited by the sandwich-structured transducer is injected into the low-loss resonant cavity, so that standing wave resonance is caused. In a further embodiment, the use of piezoelectric transducers allows the transmission and extraction of higher harmonic frequencies of the fundamental frequency response therein, since the cavity thickness is much greater than the acoustic wave wavelength. As long as the frequency can satisfy the integer multiple of λ/2 of the substrate surface parallel interval, it is possible to ensure that the HBAR resonator has a resonance frequency response of high Q value.

In some embodiments, the substrate 801 of the resonator body 800 may be made of Si. In other embodiments, the substrate 801 of the resonator body 800 can be made of SiC. In this way, the substrate 801 made of SiC can act as both a resonant cavity and a suspended bottom electrode to provide a longitudinal electric field, thereby reducing the additional metal substrate electrode, which makes the structure quite simple. In addition, by using SiC, the complicated process and interface loss due to the metal substrate electrode can be eliminated, thereby ensuring good performance of the resonator body 800.

With continued reference to fig. 9, a schematic front view of one possible implementation of a resonator body 900 is shown. As shown, the resonator body 900 is generally a laminated structure, and includes a substrate 901 at the bottom and a piezoelectric film 902 over the substrate 901. A signal terminal 903 and a ground terminal 904 are provided above the piezoelectric film 902. Unlike the structure in fig. 8a and 8b, a bottom electrode 905, a first reflective layer 906, and a second reflective layer 907 are provided in this order between the substrate 901 and the piezoelectric film 902. As shown, a bottom electrode 905 is coupled to the piezoelectric film 902, a second reflective layer 907 is coupled to the substrate 901, and a first reflective layer 906 is positioned between the bottom electrode 905 and the second reflective layer 907. It should be noted that the thicknesses of the layers shown in fig. 9 are merely illustrative and not limiting. In some embodiments, the first reflective layer 906 is made of a first material and the second reflective layer 907 is made of a second material, wherein the acoustic impedance of the first material may be higher than the acoustic impedance of the second material. In a further embodiment, the substrate 901 may be made of sapphire, the bottom electrode 905 may be made of molybdenum, the first reflective layer 906 may be made of molybdenum, the second reflective layer 907 may be made of aluminum, and the piezoelectric film 902 may be ErScAlN thin film. It is noted that the materials listed herein are illustrative only and not limiting. Each layer in the resonator body 900 may be made of materials other than those listed herein, the particular materials not being limited by embodiments of the present disclosure.

Referring back to fig. 5, some exemplary topology circuit structures of filter 50 according to embodiments of the present disclosure are described below in conjunction with fig. 5. As shown in fig. 5, the filter 50 generally includes an acoustic resonator 54 and a low temperature co-fired ceramic resonator 56 coupled together, with the package substrate not shown in fig. 5 for simplicity.

As shown on the right side IN fig. 5, the low temperature co-fired ceramic resonator 56 includes an input terminal IN and an output terminal OUT, and a plurality of capacitors 561 coupled IN series between the input terminal IN and the output terminal OUT. The capacitors 561 form a first coupling point P1 therebetween. The low temperature co-fired ceramic resonator 56 may also include one or more resonant cells 562 coupled between the first coupling point P1 and the common coupling end REF, respectively. It is understood that the resonating unit 562 in fig. 5 may be fabricated using the resonating unit 700 in fig. 7. As shown in fig. 5, an equivalent capacitor 563 and an equivalent inductance 564 coupled in parallel are included in each resonant cell 562. It will be appreciated that the topology of the low temperature co-fired ceramic resonator 56 in fig. 5 is similar to the topology of the low temperature co-fired ceramic resonator 46 in fig. 4 and will not be described again here for the sake of brevity.

As shown on the left side in fig. 5, the topology of the acoustic resonator 54 in the filter 50 is described below. As shown in fig. 4, the acoustic resonator 54 includes a plurality of first series resonators 541, the first series resonators 541 being coupled in series, and one or more second coupling points P2 being provided between the first series resonators 541. Four first series resonators 541 are shown in fig. 5, and four second coupling points P2 are formed. It should be understood that this is merely illustrative. In other embodiments, more or fewer first series resonators 541 and second coupling points P2 therebetween may be provided, and the specific number may be adjusted accordingly as desired, and such embodiments are within the scope of the present disclosure. Furthermore, in the embodiment shown in fig. 5, there is one first series resonator body 541 between two adjacent second coupling points P2, which is also merely illustrative. As will be appreciated by those skilled in the art, since the second coupling point P2 may exist between any two first series resonators 541, any number of first series resonators 541 may exist between adjacent second coupling points P2 according to different arrangements. The embodiments of the present disclosure are not particularly limited thereto. It is understood that the first series resonator body 541 in fig. 5 may be manufactured using the resonator body 800 in fig. 8a or 8b, or the resonator body 900 in fig. 9. It should also be noted that in some embodiments, the plurality of first series resonators 541 in fig. 5 may have different resonant cell sizes from each other, so as to achieve different resonant frequency points from each other. Similarly, the plurality of first parallel resonators 542 may have different resonance unit sizes from each other, thereby realizing different resonance frequency points from each other.

As shown in fig. 5, the acoustic resonator 44 may also include one or more first parallel resonators 542. The first parallel resonators 542 are respectively coupled between one or more second coupling points P2 and a common coupling end REF 1. Four first parallel resonators 542 are shown in fig. 4, the number of which corresponds to the number of second coupling points P2. It should be appreciated that this is merely exemplary, and that in other embodiments, other numbers of branches may be provided to provide the first parallel resonator 542, depending on the actual design requirements. It should also be appreciated that while only the first parallel resonator 442 is shown in fig. 5 as being disposed between the second coupling point P2 and the common coupling end REF1, this is also merely illustrative. In some embodiments, two, three or even more first parallel resonators 542 may be provided between the second coupling point P2 and the common coupling end REF 1. In other embodiments, the first parallel resonator 542 may not be disposed between the second coupling point P2 and the common coupling end REF 1. These embodiments fall within the scope of embodiments of the present application. It will be appreciated that the first parallel resonator 542 of fig. 5 may be made using the resonator body 800 of fig. 8a or 8b, or the resonator body 900 of fig. 9.

In the embodiment shown in fig. 5, an inductor 543 is coupled between the common coupling terminal REF1 and the ground terminal. Although two inductors 543 are shown in fig. 5, it should be understood that other numbers of inductors 543 may be provided to meet different design requirements. The embodiments of the present disclosure are not particularly limited thereto. According to embodiments of the present disclosure, the number and manner of connection of the different types of devices in the filter 50 in fig. 5 may be adjusted based on different design requirements to achieve the desired design effect. Embodiments according to the present disclosure have good scalability.

Some exemplary topology circuit structures of the filter 60 according to embodiments of the present disclosure are described below with reference to fig. 6. As shown in fig. 6, the filter 60 generally includes an acoustic resonator 64 and a low temperature co-fired ceramic resonator 66 coupled together, the package substrate not being shown in fig. 6 for purposes of brevity.

As shown on the right side IN fig. 6, the low-temperature co-fired ceramic resonator 66 includes an input terminal IN and an output terminal OUT, and a plurality of capacitors 661 coupled IN series between the input terminal IN and the output terminal OUT. The capacitors 661 form a first coupling point P1 therebetween. The low temperature co-fired ceramic resonator 66 may further include one or more resonant cells 662 coupled between the first coupling point P1 and the common coupling end REF, respectively. It is understood that the resonant cell 662 of fig. 6 may be fabricated using the resonant cell 700 of fig. 7. As shown in fig. 6, an equivalent capacitor 663 and an equivalent inductance 664 coupled in parallel are included in each resonant cell 662. It will be appreciated that the topology of the low temperature co-fired ceramic resonator 66 in fig. 6 is similar to the topology of the low temperature co-fired ceramic resonator 46 in fig. 4 or the topology of the low temperature co-fired ceramic resonator 56 in fig. 5 and will not be described again here for the sake of brevity.

As shown on the left side in fig. 6, the topology of the acoustic resonator 64 in the filter 60 is described below. As shown in fig. 6, the acoustic resonator 64 includes a plurality of second series resonators 642, and these second series resonators 642 are coupled in series and connected to a plurality of capacitors 661 in the low-temperature co-fired ceramic resonator 66. One of the second series resonators 642 includes a first end T1 and a second end T2 disposed opposite each other, wherein the first end T1 is proximate to and coupled to the plurality of capacitors 661 in the low temperature co-fired ceramic resonator 66 and the second end T2 is distal from the plurality of capacitors 661.

As shown in fig. 6, the acoustic resonator body 64 further includes a plurality of third series resonators 643, and the third series resonators 643 are serially coupled to a common coupling end REF. One of the third series resonators 643 includes a third end T3 and a fourth end T4 disposed opposite to each other, wherein the third end T3 is close to and coupled to the low temperature co-fired ceramic resonator 66 and the fourth end T4 is far from the low temperature co-fired ceramic resonator 66.

With continued reference to fig. 6, as shown, a first end T1 of the second series resonant body 642 is coupled to a fourth end T4 of the third series resonant body 643 via a fourth series resonant body 644, and a second end T2 of the second series resonant body 642 is coupled to a third end T3 of the third series resonant body 643 via a fifth series resonant body 645.

As shown in fig. 6, a third coupling point P3 is provided between the plurality of second series resonators 642, and a fourth coupling point P4 is provided between the plurality of third series resonators 643. In fig. 6 a third coupling point P3 and a corresponding fourth coupling point P4 are shown. It should be understood that this is merely illustrative. In other embodiments, other numbers of second series resonators 642 and third coupling points P3 therebetween, or other numbers of third series resonators 643 and fourth coupling points P4 therebetween may be provided, and the specific numbers of corresponding resonators and coupling points may be adjusted accordingly as desired, which fall within the scope of the disclosure. Furthermore, it will be appreciated by those skilled in the art that any number of second series resonators 642 may be present between adjacent third coupling points P3, depending on the arrangement. Similarly, any number of third series resonators 643 may exist between adjacent fourth coupling points P4. The embodiments of the present disclosure are not particularly limited thereto.

A second parallel resonator 646 may be coupled between the third coupling point P3 and the fourth coupling point P4, respectively. Although only the second parallel resonator 646 is shown in fig. 6 as being disposed between the third coupling point P3 and the fourth coupling point P4, this is also merely illustrative. In some embodiments, two, three or even more second parallel resonators 646 may be provided between the third coupling point P3 and the fourth coupling point P4. In other embodiments, the second parallel resonator body 646 may not be disposed between the third coupling point P3 and the fourth coupling point P4.

As shown in fig. 6, a fifth coupling point P5 is provided between the plurality of second series resonators 642, and correspondingly, a sixth coupling point P6 is provided between the plurality of third series resonators 643. In fig. 6, a fifth coupling point P5 and a corresponding sixth coupling point P6 are shown. It should be understood that this is merely illustrative. In other embodiments, other numbers of second series resonators 642 and sixth coupling points P6 therebetween may be provided, or other numbers of third series resonators 643 and sixth coupling points P6 therebetween may be provided, and the specific numbers of corresponding resonators and coupling points may be adjusted accordingly as desired, which fall within the scope of the disclosure. Furthermore, it will be appreciated by those skilled in the art that any number of second series resonators 642 may be present between adjacent fifth coupling points P5, depending on the arrangement. Similarly, any number of third series resonators 643 may exist between adjacent sixth coupling points P6. The embodiments of the present disclosure are not particularly limited thereto. A plurality of third parallel resonators 647 are coupled between the fifth coupling point P5 and the sixth coupling point P6, respectively, and a resistor 648 is coupled between the third parallel resonators 647. It is understood that the second series resonator body 642, the third series resonator body 643, the fourth series resonator body 644, the fifth series resonator body 645, the second parallel resonator body 646, or the third parallel resonator body 647 in fig. 6 may be manufactured using the resonator body 800 in fig. 8a or 8b, or the resonator body 900 in fig. 9.

It should also be noted that in some embodiments, one or more of the second series resonant bodies 642, one or more of the third series resonant bodies 643, one or more of the fourth series resonant bodies 644, one or more of the fifth series resonant bodies 645, one or more of the second parallel resonant bodies 646, or one or more of the third parallel resonant bodies 647 in fig. 6 may have different resonant cell sizes from one another, thereby achieving different resonant frequency points from one another. According to embodiments of the present disclosure, the number and manner of connection of the different types of devices in the filter 60 in fig. 6 may be adjusted based on different design requirements to achieve the desired design effect. Embodiments according to the present disclosure have good scalability.

The embodiment of the disclosure fully utilizes the advantages of the low-temperature co-fired ceramic resonator and the acoustic resonator, and can realize wider bandwidth. And, through the cascade connection between low temperature cofired ceramic resonator and the acoustic resonator, because the Q value of low temperature cofired ceramic resonator is significantly higher than integrated passive device resonator in prior art, consequently can realize the Q value that is significantly higher than current filter. The filter according to embodiments of the present disclosure can control the device volume within a smaller value while ensuring good performance than in the prior art where a dielectric filter that occupies a larger volume is required. In addition, the problem of poor near-end suppression can be avoided compared to a solution using only low temperature co-fired ceramic resonators.

In another aspect of the present disclosure, a radio frequency system is provided. The radio frequency system comprises a radio frequency circuit and the filter described above. In embodiments of the present disclosure, a radio frequency system may include a separate antenna, a separate Radio Frequency Front End (RFFE) device, and a separate radio frequency chip. Radio frequency chips are sometimes also referred to as receivers, transmitters or transceivers. The antenna, the radio frequency front end device and the radio frequency processing chip can all be manufactured and sold separately. Of course, the rf system may also employ different devices or different integration schemes based on power consumption and performance requirements. For example, part of the devices belonging to the rf front-end are integrated in an rf chip, which may also be referred to as an rf antenna module or antenna module, and even both the antenna and the rf front-end devices are integrated in the rf chip.

In yet another aspect of the present disclosure, an electronic device is provided. The electronic device generally includes a processor, a circuit board, and a filter including the above description, wherein the filter and the processor are disposed on the circuit board. The radio frequency system and the electronic device may be adapted for wireless communication in a variety of practical environments.

The electronic device of the embodiment of the application can be a notebook computer, a wearable device, an unmanned aerial vehicle, a mobile phone, a router, an enterprise wireless access device, an access network fixed terminal and the like, and the application is not limited to the above. For example, taking a 5G communication system architecture as an example, a scenario in which the embodiments of the present application are used may include a Balun filter (Balun filter), a band-PASS FILTER (BPF) Low-pass filter (Low-PASS FILTER, LPF), and other radio-frequency devices.

It should be understood that in a wireless communication system, devices can be classified into devices providing wireless network services and devices using wireless network services. Devices providing wireless network services are those devices that make up a wireless communication network, which may be referred to simply as network devices (network equipment), or network elements. Network devices are typically owned by and are responsible for operation or maintenance by operators (e.g., china mobile and Vodafone) or infrastructure providers (e.g., iron tower companies). The network devices may be further divided into radio access network (radio access network, RAN) devices and Core Network (CN) devices. A typical RAN apparatus includes a Base Station (BS).

It should be appreciated that a base station may also sometimes be referred to as a wireless Access Point (AP), or a transmitting receiving point (transmission reception point, TRP). Specifically, the base station may be a general node B (generation Node B, gNB) in a 5G New Radio (NR) system, an evolved node B (evolutional Node B, eNB) of a 4G long term evolution (long term evolution, LTE) system. Base stations may be classified as macro base stations (macro base station) or micro base stations (micro base station) according to their physical form or transmit power. The micro base station is sometimes also referred to as a small base station or small cell (SMALL CELL).

Devices that use wireless network services are typically located at the edge of the network and may be referred to simply as terminals (terminals). The terminal can establish connection with the network device and provide specific wireless communication service for the user based on the service of the network device. It should be appreciated that terminals are sometimes referred to as User Equipment (UE), or Subscriber Units (SU), due to their closer relationship to the user. In addition, terminals tend to move with users, sometimes referred to as Mobile Stations (MSs), relative to base stations that are typically placed at fixed locations. In addition, some network devices, such as a Relay Node (RN) or a wireless router, may be considered terminals because they have UE identities or belong to users.

Specifically, the terminal may be a mobile phone (mobile phone), a tablet computer (tablet computer), a laptop computer (laptop computer), a wearable device (such as a smart watch, a smart bracelet, a smart helmet, smart glasses), and other devices with wireless access capability, such as a smart car, various internet of things (internet of thing, IOT) devices, including various smart home devices (such as smart meters and smart appliances) and smart city devices (such as security or monitoring devices, intelligent road transportation facilities), and the like.

Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are example forms of implementing the claims.

Claims

1. A filter, comprising:

A package substrate including a first side and a second side opposite the first side;

A low temperature co-fired ceramic resonator coupled to a first side of the package substrate; and

An acoustic resonator is coupled to the first side or the second side of the package substrate and is coupled in cascade with the low temperature co-fired ceramic resonator.

2. The filter of claim 1, wherein the low temperature co-fired ceramic resonator is coupled to the first side of the package substrate via bumps or bond wires or directly coupled to the first side of the package substrate.

3. The filter of any of claims 1-2, wherein the acoustic resonator is coupled to the first side or the second side of the package substrate via bumps or bond wires or the acoustic resonator is coupled directly to the first side or the second side of the package substrate.

4. The filter of any of claims 1-2, wherein the low temperature co-fired ceramic resonator comprises one or more of a transverse magnetic wave resonator, a transverse electric wave resonator, a transverse electromagnetic wave resonator, a dual mode resonator.

5. The filter of any of claims 1-4, wherein the low temperature co-fired ceramic resonator comprises:

An input and an output; and

A plurality of capacitors coupled in series between the input and the output, with one or more first coupling points between the plurality of capacitors; and

One or more resonant cells coupled between the one or more first coupling points and the common coupling end, respectively.

6. The filter of claim 5, wherein each resonant cell comprises a first layer, a second layer, and a third layer stacked in sequence, the first layer and the third layer having a dielectric constant lower than a dielectric constant of the second layer.

7. The filter of claim 5, wherein each resonant cell comprises an equivalent capacitor and an equivalent inductance coupled in parallel.

8. The filter of any of claims 1-7, wherein the acoustic resonator comprises one or more of a bulk acoustic wave resonator, an HBAR resonator, XBAW resonator, an XBAR resonator, a surface acoustic wave resonator.

9. The filter of any of claims 1-8, wherein the acoustic resonator comprises:

a plurality of first series resonators coupled in series with one or more second coupling points therebetween; and

One or more first parallel resonators are coupled between the one or more second coupling points and the common coupling end, respectively.

10. The filter of claim 9, wherein the common coupling is a ground.

11. The filter of claim 9, wherein one or more inductors are coupled between the common coupling terminal and ground terminal.

12. The filter according to any of claims 9-11, wherein the acoustic resonator comprises:

a plurality of second series resonators coupled in series with each other and coupled to the plurality of capacitors; and

And a plurality of third series resonators coupled in series with each other and coupled to the common coupling terminal.

13. The filter of claim 12, wherein one of the plurality of second series resonators comprises:

a first end coupled to the low temperature co-fired ceramic resonator and a second end opposite the first end;

One of the plurality of third series resonators includes:

A third terminal coupled to the low temperature co-fired ceramic resonator and a fourth terminal opposite the third terminal;

The first end is coupled to the fourth end via a fourth series resonator,

The second end is coupled to the third end via a fifth series resonator body.

14. The filter of any of claims 12-13, wherein there are one or more third coupling points between the plurality of second series resonators, and one or more fourth coupling points between the plurality of third series resonators, the third coupling points and the fourth coupling points each having a second parallel resonator coupled therebetween.

15. The filter of any of claims 12-14, wherein there are one or more fifth coupling points between the second plurality of series resonators, one or more sixth coupling points between the third plurality of series resonators, a third plurality of parallel resonators coupled between the fifth coupling point and the sixth coupling point, respectively, and a resistor coupled between the third plurality of parallel resonators.

16. A filter according to any of claims 9-15, wherein each first series resonator body or each first parallel resonator body comprises:

a substrate;

A piezoelectric film disposed over the substrate;

A signal terminal disposed above the piezoelectric film; and

And a ground terminal disposed over the piezoelectric film or between the piezoelectric film and the substrate.

17. A filter according to any of claims 14-15, wherein each second series resonator body or each second parallel resonator body comprises:

a substrate;

A piezoelectric film disposed over the substrate;

A signal terminal disposed above the piezoelectric film; and

18. The filter of any of claims 16-17, wherein a bottom electrode, a first reflective layer, and a second reflective layer are disposed between the substrate and the piezoelectric film at a time, the bottom electrode being coupled to the piezoelectric film, the second reflective layer being coupled to the substrate.

19. The filter of claim 18, wherein the first reflective layer is made of a first material, the second reflective layer is made of a second material, and the acoustic impedance of the first material is higher than the acoustic impedance of the second material.

20. The filter of any of claims 1-19, wherein the package substrate comprises one or more of a low temperature co-fired ceramic substrate, a printed circuit board substrate, a glass via substrate.

21. A radio frequency system, comprising:

The filter and radio frequency circuit of any of claims 1-20.

22. An electronic device, comprising:

A processor;

A circuit board; and

The filter according to claim 1 to 20,

The filter and the processor are disposed on the circuit board.