A hybrid bandpass filter

Abstract

The present invention discloses a hybrid bandpass filter, which includes a first acoustic wave resonance unit, a filter unit, a second acoustic wave resonance unit, a matching substrate, a polymer-filled shell, and a signal port. The input end of the first acoustic wave resonance unit is connected to the input end of the hybrid bandpass filter and receives an input signal through the input end of the hybrid bandpass filter; the input end of the filter unit is connected to the output end of the first acoustic wave resonance unit, and the output end of the filter unit is connected to the input end of the second acoustic wave resonance unit; the output end of the second acoustic wave resonance unit is connected to the output end of the hybrid bandpass filter and outputs a signal through the output end of the hybrid bandpass filter; the first acoustic wave resonance unit, the filter unit, and the second acoustic wave resonance unit are welded on the matching substrate; the polymer-filled shell fills the outside of the first acoustic wave resonance unit, the filter unit, and the second acoustic wave resonance unit and completely encapsulates these units.

Description

Technical Field

[0001] The present invention relates to the field of electronic technology, and in particular to a bandpass filter. Background Art

[0002] With the rapid development of mobile communications, the demand for mobile phone RF filters has exploded. RF filters play a crucial role in RF front-end modules. They filter out out-of-band interference and noise to meet the signal-to-noise ratio requirements of RF systems and communication protocols. As communication protocols become increasingly complex, the demands for both in-band and out-of-band performance are also increasing, making filter design increasingly challenging.

[0003] In recent years, various equipment and chip vendors have begun offering commercial 5G mobile phones and chips. Compared to previous mobile communication networks, 5G communications incorporates numerous new frequency bands, which are relatively broad, primarily including 3.3-3.8 GHz, 3.3-4.2 GHz, 4.4-5.0 GHz, and 24.25-29.5 GHz. With the development of 5G communications, the number of frequency bands supported by mobile phones continues to increase. Since each frequency band requires its own filter, the number of filters required in mobile phones is also increasing. Currently, the main miniaturized filter designs include LTCC (Low Temperature Co-fired Ceramic), IPD (Integrated Passive Device), SAW (Surface Acoustic Wave), BAW (Bulk Acoustic Wave), and FBAR (Film Bulk Acoustic Resonator). Among them, LTCC filters are made using screen printing and multi-layer stacking processes, so the product size is large and the consistency is poor; IPD filters are designed using planar spiral inductors and MIM capacitors, where the inductor has a low Q value, large in-band losses, and a poor rectangular coefficient; SAW, BAW, and FBAR are not suitable for making broadband filters.

[0004] The rapid development of 5G communication technology has placed increasingly challenging demands on RF devices in terms of miniaturization, higher frequency processing, higher performance, low power consumption, and low cost. As a core component in the front end of RF devices, bulk acoustic wave (BAW) filters offer the advantages of higher operating frequencies, lower insertion loss, and higher power handling capabilities, all while maintaining a relatively small size. In 5G mobile communication terminal devices, BAW filters are widely used in the 2.5 GHz to 6 GHz frequency range. BAW filters typically employ either an FBAR (Film Bulk Acoustic Resonator) or a BAW-SMR (Solidly Mounted Resonator) structure. The FBAR filter's active portion is constructed as a sandwich piezoelectric oscillator stack, consisting of a metal bottom electrode, a metal top electrode, and a piezoelectric film between the two electrodes. The use of highly c-axis-oriented AlN or AlScN piezoelectric materials is a key feature of FBAR filters, as the acoustic waves in these filters are excited longitudinally through the thickness.

[0005] When an electrical signal is applied to a FBAW resonator, the piezoelectric film within the device converts the electrical signal into an acoustic wave through the inverse piezoelectric effect. This acoustic wave is reflected at the interface, forming a standing wave within the piezoelectric film. Acoustic signals that fully reflect the acoustic wave within the device resonate, while signals that do not resonate are attenuated. Because the operating frequency of a FBAW resonator is inversely proportional to the thickness of the piezoelectric material, the thickness of the piezoelectric layer determines the operating frequency range of the resulting BAW device.

[0006] At present, the piezoelectric layer of most bulk acoustic wave filters is made of AlN polycrystalline thin films. Polycrystalline thin films with c-axis preferred orientation are usually grown on the surface of Si substrates using PVD sputtering technology. However, this method has several disadvantages. First, due to the lattice mismatch with the substrate, the epitaxial AlN film on the Si substrate is usually polycrystalline, the film dislocation defect density is relatively high, and the C-axis preferred orientation deteriorates with decreasing thickness. Generally, when the thickness is less than 500nm, the full width at half maximum (FWHM) of the rocking curve measured by XRD is greater than 1.6 degrees. As a thin piezoelectric layer, its performance is usually not as good as that of a single crystal film, especially in higher frequency bands. The performance is much worse than that of a single crystal film. The piezoelectric coupling coefficient of a single crystal AlN film is between 6% and 7%, which is difficult to meet the bandwidth requirements of 5G communications.

[0007] One method for increasing bandwidth is to dope AlN thin films with rare earth elements, typically scandium (Sc). The electromechanical coupling coefficient of the doped piezoelectric material can be significantly improved, depending on the doping element and concentration. However, the resonator's quality factor (Q) is also reduced because the doped film has a lower stiffness than undoped AlN. Consequently, the filter's insertion loss increases, leading to poor filtering performance and increased power consumption.

[0008] The thickness of the piezoelectric film in the FBAR filter is inversely proportional to the operating frequency. The thickness of the piezoelectric film of the filter operating at extremely high frequencies (such as 10GHz) is about 200nm. Manufacturing such ultra-thin piezoelectric materials is very challenging. The thinner the piezoelectric film, the more difficult it is to maintain appropriate hardness, and its own crystal defects and pressure are more likely to cause cracks. In addition, after polycrystalline AlN is doped, the crystal orientation deteriorates, and an AlN seed layer needs to be added, resulting in a thinner actual piezoelectric layer and a lower actual doping average concentration.

[0009] Compared to polycrystalline AlN films, single-crystal AlN films have advantages such as higher acoustic velocity, better crystallinity, higher piezoelectric constant and electromechanical coupling coefficient, which will enable BAW filters to meet the higher bandwidth and more stringent performance requirements of 5G communications. Therefore, the next generation of high-frequency FBARs requires defect-free or nearly defect-free single-crystal films.

[0010] High-quality single-crystal piezoelectric films, typically with a (002) XRD rocking curve full width at half maximum (FWHM) of less than 1 degree, have been successfully developed through a unique process. This process is described in our company's patent entitled "Method for preparing single-crystal piezoelectric radio frequency resonators and filters" (patent number CN108365829), which discloses a novel method for obtaining single-crystal piezoelectric films using heterogeneous film transfer. This method involves depositing an AlScN piezoelectric film on a sapphire / GaN substrate to obtain a single-crystal AlScN film with minimal lattice mismatch. The epitaxial AlScN film is then bonded to a Si / SiO2 substrate using an Au-Au bonding process. Due to the small band gap of GaN (3.4 eV compared to sapphire), a 248 nm laser is used to scan the wafer from the back of a transparent sapphire substrate. The laser passes through the sapphire and is absorbed by the GaN layer, which then decomposes. The sapphire is separated, resulting in the epitaxially grown single-crystal AlScN piezoelectric film being transferred to a Si substrate. These single-crystal piezoelectric films typically have a thickness of 200 nm to 1000 nm, with a roughness of less than 1 nm. The films exhibit a strong c-axis orientation perpendicular to the (002) plane, with a rocking curve FWHM of less than 1 degree.

[0011] Currently, the common method for growing AlN or AlScN involves PVD sputtering to deposit a piezoelectric film on a Si or SiO2 substrate. However, using this method, single-crystal AlN or AlScN is generally not obtainable due to the huge lattice mismatch. U.S. Patent No. 10,797,681 discloses a method for manufacturing a single AlN or AlScN that uses a "thin film transfer concept." This method involves depositing an AlScN piezoelectric film on a sapphire / GaN substrate (commonly available sapphire wafers are coated with GaN), thereby producing a single-crystal AlScN film with a small lattice mismatch. Next, the epitaxial AlScN film is bonded to a Si substrate using an Au-Au bonding process, and then a 248nm laser is used to scan the wafer from the back of a transparent sapphire substrate. Because the band gap of sapphire is large and the band gap of GaN is small, the laser can pass through the sapphire and be absorbed by the GaN layer, and the GaN is decomposed into Ga and nitrogen. The sapphire is separated, so that the single-crystal AlScN piezoelectric film epitaxially grown on the sapphire / gallium nitride substrate can be transferred to the Si substrate.

[0012] Therefore, there is an urgent need for a small-sized bandpass filter that can still provide a wide passband with low loss and a high squareness coefficient. Summary of the Invention

[0013] To achieve the above objectives and address the above needs, the present invention, in an embodiment, combines the characteristics of an IPD filter and an acoustic wave filter to create an integrated hybrid bandpass filter that combines an IPD filter and multiple acoustic wave resonators. The hybrid bandpass filter in this embodiment of the present invention includes a first acoustic wave resonator unit, an IPD filter unit, a second acoustic wave resonator unit, a matching substrate, a polymer-filled housing, and a signal port. Depending on the specific implementation and objectives, the IPD filter can be implemented as a high-pass, low-pass, or bandpass filter.

[0014] According to an embodiment of the present invention, a hybrid bandpass filter includes:

[0015] a first acoustic wave resonance unit, wherein an input end of the first acoustic wave resonance unit is connected to an input end of the hybrid band-pass filter and receives an input signal through the input end of the hybrid band-pass filter;

[0016] a filter unit, wherein an input end of the filter unit is connected to an output end of the first acoustic wave resonance unit, and an output end of the filter unit is connected to an input end of the second acoustic wave resonance unit;

[0017] a second acoustic wave resonance unit, wherein an output end of the second acoustic wave resonance unit is connected to an output end of the hybrid band-pass filter and outputs a signal through the output end of the hybrid band-pass filter;

[0018] a matching substrate, on which the first acoustic wave resonance unit, the filter unit, and the second acoustic wave resonance unit are welded;

[0019] A polymer-filled shell is filled outside the first acoustic wave resonance unit, the filter unit, and the second acoustic wave resonance unit, and completely wraps the first acoustic wave resonance unit, the filter unit, and the second acoustic wave resonance unit;

[0020] The signal port includes a hybrid bandpass filter input terminal, a hybrid bandpass filter output terminal, and at least one ground terminal, wherein the signal port is located on the lower surface of the matching substrate.

[0021] According to an embodiment of the present invention, the input end is connected to the first acoustic resonance unit, which is further connected to the input end of the IPD filter through a matching inductor. The output end of the IPD filter is connected to the second acoustic resonance unit through a matching inductor, and the second acoustic resonance unit is connected to the output end, thereby providing the required filtering function. The two acoustic resonance units and the IPD filter are integrated on a matching substrate by using flip-chip technology.

[0022] Furthermore, in an embodiment, the first acoustic wave resonance unit and the second acoustic wave resonance unit each include at least one series acoustic wave resonator and at least one parallel acoustic wave resonator.

[0023] Furthermore, in an embodiment of the present invention, the IPD filter unit is a high-pass filter or a band-pass filter prepared on a Si, GaAs, glass or sapphire substrate, and is packaged through processes such as photolithography, etching, deposition, and sputtering.

[0024] Furthermore, in an embodiment of the present invention, the matching substrate includes an input port matching inductor, an output port matching inductor, a connecting inductor between the first acoustic wave resonance unit and the IPD filter, a connecting inductor between the IPD filter and the second acoustic wave resonance unit, and a grounding inductor connected to the parallel acoustic wave resonator.

[0025] Furthermore, in an embodiment of the present invention, the signal port includes an input terminal, an output terminal, and at least one ground terminal.

[0026] Furthermore, in an embodiment of the present invention, the matching substrate is a substrate prepared by a multi-layer lamination process, and includes a ceramic substrate and a PCB substrate, which are connected through through holes and signal ports in the matching substrate to form a communication loop.

[0027] The integrated hybrid bandpass filter according to the present invention has the characteristics of small size, light weight, low loss, high suppression, wide passband, high rectangular coefficient, etc. In addition, the present invention is prepared using a fairly mature semiconductor process with high process precision, making it very suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to better understand the present invention and show how it is implemented, reference may be made to specific implementation cases of the present invention. For implementation details, reference may be made to the accompanying drawings. It should be emphasized that the details shown in the accompanying drawings are all illustrative discussions of specific embodiments of the present invention, and are presented in the most useful and easiest to understand manner to provide the principles and concepts of the present invention. In this regard, the structural details of the present invention are not shown in more detail; the description made in conjunction with the accompanying drawings makes it clear to those skilled in the art how several forms of the present invention can be implemented in practice. In particular, in order to facilitate further understanding by those skilled in the art, the schematic diagrams are not to scale, and the thickness of some very thin layers is exaggerated. In the accompanying drawings:

[0029] Figure 1 1 is a circuit diagram of a first embodiment of an integrated hybrid bandpass filter according to the present invention;

[0030] Figure 2 For Figure 1 FIG. 1 is a schematic diagram of the structure of the filter according to the first embodiment of the present invention;

[0031] Figure 3 For Figure 1 FIG. 4 is a schematic plan view of a filter according to a first embodiment of the present invention;

[0032] Figure 4 For and in Figure 1 FIG. 5 is a schematic diagram of a matching substrate used together with a filter according to a first embodiment of the present invention;

[0033] Figure 5 To show the Figure 1 Schematic diagram of the arrangement of the input terminal, the grounding section and the output terminal used together with the filter of the first embodiment of the present invention shown in FIG;

[0034] Figure 6 Based on Figure 1 The frequency attenuation diagram of the simulation result of the filter of the first embodiment is shown in FIG;

[0035] Figure 7 A circuit diagram of an integrated hybrid bandpass filter according to a second embodiment of the present invention;

[0036] Figure 8 Based on Figure 1 The frequency attenuation diagram of the simulation result of the second embodiment filter shown in FIG;

[0037] Figure 9 This is a circuit diagram of an integrated hybrid bandpass filter according to a third embodiment of the present invention;

[0038] Figure 10 Based on Figure 9FIG. 4 is a frequency attenuation diagram of the simulation results of the filter of the third embodiment shown in FIG.

[0039] Description of reference numerals:

[0040] 1 First acoustic wave resonator unit; 2 IPD filter; 3 Second acoustic wave resonator unit; 4 Matching substrate; 5 Polymer-filled housing; 6 Signal port; 11 First acoustic wave resonator input port; 12 First acoustic wave resonator output port; 13 Series acoustic wave resonator A1; 14 Parallel acoustic wave resonator B1; 15 Ground port; 16 Empty port; 21 IPD input port; 22 IPD output port; 23 Inductor L4; 24 Inductor L5; 25 Capacitor C2; 26 Capacitor C1; 27 Capacitor C3; 28 Port Ground; 29 port ground; 210 empty port; 31 second acoustic wave resonance input port; 32 second acoustic wave resonance output port; 33 series acoustic wave resonator A2; 34 parallel acoustic wave resonator B2; 35 port ground; 36 parallel acoustic wave resonator B3; 37 port ground; 38 empty port; 41 inductor L1; 42 inductor L2; 43 inductor L3; 44 inductor L6; 45 inductor L8; 46 inductor L7; 47 inductor L9; 61 input port S1; 62 ground port G1; and 63 output port S2. DETAILED DESCRIPTION

[0041] To make the technical means, innovative features, objectives and effects of the present invention easier to understand, the present invention is further described below with reference to specific embodiments.

[0042] See now Figure 1 , the circuit structure of the bandpass filter according to the first embodiment of the present invention is shown. The structure of the bandpass filter includes a first acoustic wave resonance unit, an IPD filter and a second acoustic wave resonance unit. More specifically, Figure 1 The first acoustic wave resonance unit includes a series acoustic wave resonator and a parallel acoustic wave resonator. The IPD filter is a third-order elliptic function high-pass filter. The second acoustic wave resonance unit includes a series acoustic wave resonator and two parallel acoustic wave resonators. In addition, it also includes two port matching inductors, two connection inductors, and three grounding inductors connected to the parallel acoustic wave resonators.

[0043] In the first embodiment of the bandpass filter, input terminal S1 is connected to one end of series acoustic wave resonator A1, and the other end of series acoustic wave resonator A1 is connected to one end of capacitor C1 via matching inductor L3. The other end of capacitor C1 is connected to one end of series acoustic wave resonator A2 via matching inductor L6, and the other end of series acoustic wave resonator A2 is connected to output terminal S2. Port matching inductor L1 is connected to input terminal S1 at one end, and the other end of port matching inductor L1 is grounded.

[0044] One end of the parallel acoustic wave resonator B1 is connected between the input terminal S1 and the series acoustic wave resonator A1. The other end of the parallel acoustic wave resonator B1 is connected to inductor L2, and the other end of inductor L2 is grounded. Capacitor C2 is connected between matching inductor L3 and capacitor C1. Capacitor C2 is connected to inductor L4, and the other end of inductor L4 is grounded. Capacitor C3 is connected between capacitor C1 and matching inductor L6. Specifically, one end of capacitor C3 is connected to capacitor C1, and the other end of capacitor C3 is connected to inductor L5, which is in turn grounded. One end of the parallel acoustic wave resonator B2 is connected between matching inductor L6 and the series acoustic wave resonator A2. The other end of the parallel acoustic wave resonator B2 is connected to one end of inductor L7, and the other end of inductor L7 is grounded. One end of the parallel acoustic wave resonator B3 is connected between the series acoustic wave resonator A2 and the output terminal S2. The other end of the parallel acoustic wave resonator B3 is connected to one end of inductor L8, and the other end of inductor L8 is grounded. Finally, the output terminal S2 is connected to one end of the port matching inductor L9, and the other end of the port matching inductor L9 is grounded.

[0045] Figure 1 The resonators shown in , such as A1, B1, etc., are composed of two independent resonators. Figure 1 As shown, resonator A1 can be composed of two separate resonators that are connected from bottom to bottom. Where "B" refers to the bottom electrode of a particular resonator, and "T" refers to the top electrode of the resonator. Therefore, in the case of resonator A1, it is composed of two resonators with their bottom electrodes connected together. Similarly, the other resonators shown (i.e., B1, B2, A2, B3) are each composed of two separate resonators with their bottom electrodes connected together. It should be understood that the optional use of these two bottom-electrode connected resonators may be used for some, all, or possibly none of the resonators, depending on the specific application and circuit design.

[0046] like Figure 2As shown, a bandpass filter according to a first embodiment of the present invention includes a first acoustic resonator unit 1, an IPD filter 2, and a second acoustic resonator unit 3. These subunits are arranged on a matching substrate 4, which is housed in a polymer-filled housing 5 and has signal ports 6 for input / output interconnection. This arrangement also includes port connectors 7, 8, and 9. These port connectors 7, 8, and 9 are used to form metal bumps in various electrodes, which then allow these metal bumps to be bonded to corresponding metal electrode areas on the substrate 4. This enables connection of corresponding leads to the ports of the first acoustic resonator unit 1, the IPD filter 2, and the second acoustic resonator unit 3. As described herein, the first acoustic resonator unit 1 is connected to the input of the IPD filter via a matching inductor, and the output of the IPD filter is connected to the second acoustic resonator unit via a matching inductor. Finally, the two acoustic resonators and the IPD filter are integrated onto the matching substrate 4 using flip-chip interconnect technology. The polymer-filled housing 5 is formed externally to the first acoustic resonator unit 1, the IPD filter 2, and the second acoustic resonator unit 3 and has approximately the same length and width as the matching substrate 4. One function of the polymer-filled housing 5 is to isolate the air and prevent the circuit from oxidizing, thereby protecting the stability of each solder joint. In a specific embodiment, the package size of the resulting integrated hybrid bandpass filter is approximately 2.0 mm×1.25 mm×0.6 mm.

[0047] like Figure 3 、 Figure 4 、 Figure 5 As shown, according to the integrated hybrid bandpass filter of the first embodiment of the present invention, due to the high operating frequency of this embodiment and the small area of ​​a single FBAR resonator, two symmetrical FBAR resonators are connected in series to form a set of resonances. By dividing a single resonator into two symmetrical resonators in a series path or a parallel path, better performance can be obtained. Specifically, if a single resonator is used, the available area may be too small; however, if a single resonator can be divided into two resonators, a final resonator with an increased area can be provided. Generally, when a larger area is provided to implement a resonator, the performance of the resonator will be improved. The first acoustic resonance unit 1 includes a port matching inductor L1 (41), a series acoustic wave resonator A1 (13), a parallel acoustic wave resonator B1 (14) and an inductor L2 (42). The IPD filter unit includes an inductor L4 (23), an inductor L5 (24), a capacitor C1 (26), a capacitor C2 (25) and a capacitor C3 (27). The second acoustic resonance unit 2 includes an inductor L7 (46), an inductor L8 (45), a series acoustic wave resonator A2 (33), a parallel acoustic wave resonator B2 (34), a parallel acoustic wave resonator B3 (36) and a port matching inductor L9 (47).

[0048] The physical connections of the components of the bandpass filter of the first embodiment of the present invention are as follows. Figure 5 ) is connected to the input end 11 of the first acoustic wave resonance unit through a through hole. Specifically, the input end 11 is connected to the series acoustic wave resonator A1 (13), and the series acoustic wave resonator A1 (13) is connected to the output end 12, which is connected to the input end 21 of the IPD through a matching inductor L3 (43). The input end 21 of the IPD is also connected to one end of the capacitor C1 (26), and the other end of the capacitor C1 (26) is connected to the output end 22 of the IPD. The output end 22 of the IPD is connected to the input end 31 of the second acoustic wave resonance unit through a matching inductor L6 (44). The input end 31 is connected to one end of the series resonator A2 (33), and the other end of the series resonator A2 (33) is connected to the output end 32 of the second acoustic wave resonance unit, and the output end 32 is connected to the output terminal S2 (63) of the hybrid filter through a through hole.

[0049] The ground inductor L1 (41) is connected between the input terminal S1 (61) of the hybrid filter and the input terminal 11 of the first acoustic wave resonance unit. The parallel acoustic wave resonator B1 (14) is connected between the input terminal 11 of the first acoustic wave resonance unit and the series acoustic wave resonator A1 (13). The other end of the parallel acoustic wave resonator B1 (14) is connected to the port 15, which is connected to the inductor L2 (42) through a through hole. The other end of the inductor L2 (42) is connected to the ground terminal 62 through a through hole. One end of the capacitor C2 (25) is connected between the input terminal 21 of the IPD and the capacitor C1 (26), and the other end of the capacitor C2 (25) is connected to the inductor L4 (23). The inductor L4 (23) is connected to the ground port 28, and the ground port 28 is connected to the ground terminal (62) through a through hole. One end of capacitor C3 (27) is connected between capacitor C1 (26) and output terminal 22 of the IPD, and the other end of capacitor C3 (27) is connected to inductor L5 (24). Inductor L5 (24) is connected to ground terminal 29, and ground terminal 29 is connected to ground terminal (62) through a through hole.

[0050] One end of the parallel acoustic wave resonator B2 (34) is connected between the input end 31 of the second acoustic resonance unit and the series acoustic wave resonator A2 (33), while the other end of the parallel acoustic wave resonator B2 (34) is connected to the port 35. The port 35 is connected to one end of the inductor L7 (46) through a through hole, and the other end of the inductor L7 (46) is connected to the ground terminal 62 through a through hole. One end of the parallel acoustic wave resonator B3 (36) is connected between the series acoustic wave resonator A2 (33) and the output end 32 of the second acoustic wave resonance unit, while the other end of the parallel acoustic wave resonator B3 (36) is connected to the port 37. The port 37 is connected to the inductor L8 (45) through a through hole, and the inductor L8 (45) is connected to the ground terminal 62 through a through hole. The ground inductor L9 (47) is connected between the output end 32 of the second acoustic wave resonance unit and the output end S1 (63).

[0051] Figure 6 The three-dimensional electromagnetic field simulation results of the frequency attenuation provided by the bandpass filter according to the first embodiment of the present invention are shown. The simulation results show that the center frequency of the bandpass filter is 4.7 GHz. The passband bandwidth is 4.4 GHz to 5.0 GHz, and the insertion loss within the passband is less than 2.5 dB. In the stopband, the rejection is greater than 30 dB from DC to 4.2 GHz and greater than 35 dB from 5.15 to 5.85 GHz.

[0052] As reference Figure 7 FIG. 1 is a circuit structure of a hybrid bandpass filter according to a second embodiment of the present invention. The second embodiment is similar to FIG. Figure 1 In the first embodiment shown, similar components are labeled with similar reference numerals in both figures. However, compared with the first embodiment, the filter of the second embodiment includes a first acoustic wave resonance unit, which includes a series acoustic wave resonator and two parallel acoustic wave resonators. The second parallel acoustic wave resonator is composed of a parallel acoustic wave resonator B4 and an inductor L10 connected in series. Similar to the first embodiment, a cubic elliptic function high-pass filter is used as the IPD filter. Similarly, similar to the first embodiment, Figure 7 The second embodiment filter shown in FIG includes a second acoustic resonance unit having one series acoustic wave resonator and two parallel acoustic wave resonators. In addition, there are two port matching inductors, two connection or matching inductors and four grounding inductors, each connected to one of the parallel acoustic wave resonators. Figure 1 In contrast to the circuit layout presented in Figure 7 In the circuit layout, the series LC arrangement is relative to Figure 1 Specifically, Figure 1 In the circuit, C2 is connected to L4, L4 is grounded, C3 is connected to L5, and L5 is grounded. Figure 7 In the embodiment, L4 is connected to C2, C2 is grounded, L5 is connected to C3, and C3 is grounded. In terms of electrical performance, Figure 1 and Figure 7 There should be no difference between the operation of either arrangement.

[0053] Figure 8 The following figure shows the simulation results of a three-dimensional electromagnetic field showing the frequency attenuation provided by the bandpass filter according to the second embodiment of the present invention. As can be seen from these simulation results, the results of the hybrid filter according to the second embodiment are similar to those of the first embodiment. It should be noted that when one or more parallel acoustic wave resonators are used in the hybrid bandpass filter, the insertion loss in the passband increases slightly.

[0054] Now refer to Figure 9, which is the circuit structure of the bandpass filter of the third embodiment of the present invention. Similar to the filter of the first embodiment mentioned above, in the circuit of the third embodiment, the first acoustic resonance unit includes a series acoustic wave resonator and a parallel acoustic wave resonator. In contrast, in the third embodiment, the IPD bandpass filter is implemented using a third-order elliptic function high-pass filter cascaded with a third-order elliptic function low-pass filter. The second acoustic wave resonance unit includes a series acoustic wave resonator and two parallel acoustic wave resonators. In addition, there are two port matching inductors, two connection inductors and three grounding inductors, each of which is connected to one of the parallel acoustic wave resonators. It should be noted that the inductor at the right end of the low-pass filter in the IPD filter is also used as a matching connection inductor.

[0055] Figure 10 Circuit simulation results for frequency attenuation of a bandpass filter according to a third embodiment of the present invention are shown. These simulation results demonstrate that the center frequency of this bandpass filter is 4.7 GHz. The passband bandwidth ranges from 4.4 GHz to 5.0 GHz, and the insertion loss within the passband is less than 3.0 dB. Within the attenuation band, rejection is greater than 30 dB from DC to 4.2 GHz, and greater than 30 dB from 5.15 to 9.2 GHz. Compared to the previously discussed embodiments, the third embodiment significantly extends out-of-band rejection at the high frequency end by sacrificing a small amount of in-band loss.

[0056] The integrated hybrid bandpass filter provided by the present invention has the advantages of small size, light weight, low loss, high suppression, wide passband, and high squareness coefficient. As mentioned above, the hybrid filter of the present invention is manufactured using mature semiconductor technology, resulting in high process precision and suitable for batch or mass production.

[0057] The basic principles, main features and advantages of the present invention are shown and described above. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.

[0058] In the present description of the invention and the associated claims, terms such as connected, coupled, etc. are intended and should be understood as synonyms and refer to one or both of two components being connected such that an additional element or component may be disposed therebetween.

Claims

1. A hybrid bandpass filter comprising: a first acoustic wave resonance unit, wherein an input end of the first acoustic wave resonance unit is connected to an input end of the hybrid band-pass filter and receives an input signal through the input end of the hybrid band-pass filter; a filter unit, wherein an input end of the filter unit is connected to an output end of the first acoustic wave resonance unit, and an output end of the filter unit is connected to an input end of the second acoustic wave resonance unit; a second acoustic wave resonance unit, wherein an output end of the second acoustic wave resonance unit is connected to an output end of the hybrid band-pass filter and outputs a signal through the output end of the hybrid band-pass filter; Wherein, the first acoustic wave resonance unit and the second acoustic wave resonance unit each include a parallel acoustic wave resonator; a matching substrate, on which the first acoustic wave resonance unit, the filter unit, and the second acoustic wave resonance unit are welded; A polymer-filled shell is filled outside the first acoustic wave resonance unit, the filter unit, and the second acoustic wave resonance unit, and completely wraps the first acoustic wave resonance unit, the filter unit, and the second acoustic wave resonance unit; a signal port, comprising a hybrid bandpass filter input terminal, a hybrid bandpass filter output terminal, and at least one ground terminal, wherein the signal port is located on the lower surface of the matching substrate; It is characterized in that the matching substrate includes an input port matching inductor, an output port matching inductor, a matching inductor between the first acoustic wave resonance unit and the filter, a matching inductor between the filter unit and the second acoustic wave resonance unit, and a ground inductor connected to the parallel acoustic wave resonator.

2. The hybrid bandpass filter according to claim 1, wherein The first acoustic wave resonance unit is connected to the input end of the filter unit through a first matching inductor, and the output end of the filter unit is connected to the second acoustic wave resonance unit through a second matching inductor. The first acoustic wave resonance unit, the second acoustic wave resonance unit and the filter unit are integrated and soldered on the matching substrate by a chip flip-chip method.

3. The hybrid bandpass filter according to claim 1, wherein The first acoustic wave resonance unit includes at least one series acoustic wave resonator and at least one parallel acoustic wave resonator.

4. The hybrid bandpass filter according to claim 1, wherein The second acoustic wave resonance unit includes at least one series acoustic wave resonator and at least one parallel acoustic wave resonator.

5. The hybrid bandpass filter according to claim 3 or 4, wherein: The series acoustic wave resonator and the parallel acoustic wave resonator include at least one resonator. When the resonator is composed of multiple resonators with independent top electrodes and bottom electrodes, the top electrodes or the bottom electrodes are connected to form a loop.

6. The hybrid bandpass filter according to claim 3 or 4, wherein: One end of the parallel acoustic wave resonator is connected to the path of the hybrid bandpass filter, and the other end is connected to the ground inductor.

7. The hybrid bandpass filter according to claim 1, wherein The matching substrate includes a substrate prepared by a multi-layer lamination process, including a ceramic substrate or a PCB substrate; and a communication loop formed in the matching substrate by connecting through holes and signal ports. The hybrid bandpass filter according to claim 1 , wherein the filter unit is an IPD filter.

9. The hybrid bandpass filter according to claim 8, wherein The filter unit includes a high-pass filter, a low-pass filter or a band-pass filter.

10. The hybrid bandpass filter according to claim 8, wherein The IPD filter uses silicon, gallium arsenide, glass or sapphire as a substrate material and is formed by photolithography, etching, deposition or sputtering.

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