Two-port filter with phase-shift network module, duplexer and electronic device with the same

Abstract

The present invention relates to a filter, comprising: a filter part; a first port and a second port, the filter part is connected between the first port and the second port, and comprises a first filter unit covering a low frequency band and a second filter unit covering a high frequency band; a first phase-shifting network module connected between the second filter unit and the first port; and a second phase-shifting network module connected between the second filter unit and the second port. At least one phase-shifting network module comprises: a capacitive device connected between the corresponding port and the second filter unit; and a first inductor and a second inductor, wherein: the first ends of the two inductors are respectively connected to the two ends of the capacitive device, the second ends of the two inductors are both grounded, and mutual inductance is formed between the first inductor and the second inductor.

Description

Technical Field

[0001] The embodiments of the present invention relate to the semiconductor field, and in particular, to a filter, a duplexer having the filter, and an electronic device having the filter or the duplexer. Background Art

[0002] With the development of society, people's demand for communication, satellite positioning, navigation, mobile Internet applications, etc. is growing, and the allocation of frequency band resources in wireless communication is becoming increasingly tense. The division of wireless communication frequency bands presents the characteristics of density, high frequency and steep bandwidth.

[0003] To meet the needs, wireless communication systems are developing in the direction of multi-function, multi-band, and multi-protocol. For example, it is necessary to combine different communication frequency band functions such as GSM, CDMA, WCDMA, GPS, and WIFI in wireless communication on one product. This poses a higher challenge to the RF front end in wireless communication equipment. In particular, as the size of the whole machine is becoming smaller and smaller, the frequency channel resources are becoming more and more crowded, and the intervals between different communication frequency bands are getting closer. In order to ensure that each system works normally without interfering with each other, the filter is required to provide excellent filtering performance and achieve low loss and high isolation of the receiving and transmitting signals.

[0004] Among various types of filters, thin film bulk acoustic wave filters use the piezoelectric effect of piezoelectric crystals to produce resonance. Since the resonance is generated by mechanical waves rather than electromagnetic waves as the source of resonance, the wavelength of mechanical waves is much shorter than that of electromagnetic waves. Therefore, the size of thin film bulk acoustic wave filters and the resonators they consist of is significantly reduced relative to traditional electromagnetic filters. On the other hand, since the crystal growth of piezoelectric crystals can currently be well controlled, the loss of the resonator is extremely small, the quality factor is high, and it can cope with complex design requirements such as steep transition bands and low insertion loss. Due to the small size, high roll-off, and low insertion loss of bulk acoustic wave filters, filters with this as the core have been widely used in communication systems.

[0005] However, since the piezoelectric coupling coefficient of the piezoelectric material on which the BAW resonator relies is generally not high, such as aluminum nitride (AlN) is only 0.063, the BAW filter is only suitable for narrowband filters. In order to meet the needs of RF front-end broadband filters, in recent years, relevant researchers have developed broadband filters by, for example, connecting a large inductor in parallel to a parallel resonator. Although it can change the parallel resonant frequency of the parallel resonator to achieve the purpose of widening the bandwidth, connecting a large inductor in parallel to the parallel resonator, although it widens the bandwidth, it deteriorates the out-of-band suppression. This solution can only be used when the out-of-band suppression is not high.

[0006] Currently, there is no technology that can achieve both the broadband requirements of BAW resonators and high out-of-band suppression. Summary of the invention

[0007] The present invention is proposed to alleviate or solve at least one aspect of the above-mentioned problems in the prior art.

[0008] An embodiment of the present invention proposes a filter, comprising: a filter part, including a first filter unit covering a low frequency band and a second filter unit covering a high frequency band; a first port and a second port, the filter part being connected between the first port and the second port; a first phase-shifting network module, connected between the second filter unit and the first port; and a second phase-shifting network module, connected between the second filter unit and the second port.

[0009] Optionally, the first phase-shift network module is the same as the second phase-shift network module.

[0010] Optionally, at least one phase-shift network module includes: a capacitive device connected between the corresponding port and the second filter unit; and a first inductor and a second inductor, wherein: the first ends of the two inductors are respectively connected to the two ends of the capacitive device, and the second ends of the two inductors are both grounded. Further, a mutual inductance is formed between the first inductor and the second inductor.

[0011] Optionally, at least one phase-shift network module includes: a capacitive device connected between the corresponding port and the second filter unit; and a first transmission line device and a second transmission line device, wherein the first ends of the two transmission line devices are respectively connected to the two ends of the capacitive device, and the second ends of the two transmission line devices are both grounded.

[0012] Optionally, at least one phase-shifting network module includes: a capacitive device connected between the corresponding port and the second filter unit; a transmission line device, a first end of the transmission line device is connected to one end of the capacitive device, and a second end of the transmission line device is grounded; and an inductor, a first end of the inductor is connected to the other end of the capacitive device, and a second end of the inductor is grounded.

[0013] Optionally, the filter is a thin film bulk acoustic wave filter.

[0014] According to another aspect of an embodiment of the present invention, a duplexer unit is proposed, comprising: a packaging carrier; a high-frequency bandpass filter unit and a low-frequency bandpass filter unit, the two filter units are respectively arranged on the high-frequency bandpass filter chip and the low-frequency bandpass filter chip, the high-frequency bandpass filter chip and the low-frequency bandpass filter chip are packaged on the packaging carrier, and are suitable for being commonly connected to two common ports, wherein: the high-frequency bandpass filter unit is the above-mentioned second filter unit; and the first port and the second port are respectively connected to the two common ports.

[0015] Optionally, each phase-shift network module is arranged on a corresponding phase-shift network module chip; and the phase-shift network module chip, the high-frequency bandpass filter chip and the low-frequency bandpass filter chip are all integrated on the packaging carrier board, and the corresponding chips are connected by bonding wires.

[0016] Optionally, at least one phase-shifting network module is disposed in the packaging carrier; or at least one phase-shifting network module is disposed in a high-frequency bandpass filter chip.

[0017] According to yet another aspect of the embodiments of the present invention, a duplexer is provided, comprising the above-mentioned duplexer unit.

[0018] According to another aspect of the embodiments of the present invention, an electronic device is provided, comprising the above-mentioned filter, or comprising the above-mentioned duplexer unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The following description and accompanying drawings may better help understand these and other features and advantages of various embodiments disclosed by the present invention, in which the same reference numerals always represent the same components, wherein:

[0020] Figure 1 It is a schematic diagram of a combined broadband filter (duplexer) in the prior art;

[0021] Figure 2 is a schematic diagram of a combined broadband filter (duplexer) according to an exemplary embodiment of the present invention;

[0022] Figure 3 A topological structure diagram of a combined broadband filter (duplexer) according to an exemplary embodiment of the present invention;

[0023] Figure 4 is the impedance curve of the second branch of the duplexer on the Smith chart, where the solid line is the impedance curve of the second branch when the phase shift network module is not set, and the dotted line is Figure 3 The impedance curve of the second branch when the phase-shift network module is set is shown;

[0024] Figure 5 An example is shown according to Figure 3 The amplitude-frequency response curve of the duplexer, where the horizontal axis is the frequency and the vertical axis is the insertion loss, wherein the solid line is the insertion loss when the two phase-shifting network modules exist, and the dotted line is the insertion loss when the two phase-shifting network modules do not exist;

[0025] Figure 6 for Figure 5 A local enlarged schematic diagram in FIG.

[0026] Figure 7 The return loss of the filter is shown as an example;

[0027] Figure 8 For the corresponding Figure 3 Schematic diagram of the bonding wire packaging form of the duplexer;

[0028] Fig. 9 FIG. 4 is a schematic diagram of a modified embodiment of a phase-shift network module according to the present invention. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further specifically described below by examples and in conjunction with the accompanying drawings. In the specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation of the present invention.

[0030] The present invention proposes a method for implementing a high-inhibition combined broadband filter. Figure 2 The high suppression combined broadband filter is mainly composed of two filter branches. The first filter branch is mainly composed of a low-frequency bandpass filter 10 covering the low frequency band. Figure 1 Different from the above, the second filter branch includes a high-frequency bandpass filter 20 covering the high frequency band and phase shift network modules 21 and 22 connected to both ends of the high-frequency bandpass filter 20. The phase shift network modules 21 and 22 are used to change the impedance characteristics of the high-frequency bandpass filter 20, thereby improving the insertion loss of the middle part of the broadband filter composed of the low-frequency bandpass filter 10 and the high-frequency bandpass filter 20. The input ports of the first filter branch and the second filter branch are connected in parallel to the common port 30, and the output ports of the first filter branch and the second filter branch are connected in parallel to the common port 31. The low-frequency bandpass filter and the high-frequency bandpass filter can be realized by a bulk acoustic wave resonator.

[0031] Figure 3 FIG. 4 is a topological structure diagram of a combined broadband filter (duplexer) according to an exemplary embodiment of the present invention.

[0032] like Figure 3 As shown, the combined broadband filter is mainly composed of two bulk acoustic wave filter branches.

[0033] like Figure 3As shown, the first filter branch is a filter 101 that can cover low frequencies, and its circuit topology is a 4-3 ladder structure, which is mainly composed of 4 series resonators, 3 parallel resonators, and 3 inductors. The series resonators include S11, S12, S13, and S14, the parallel resonators include P11, P12, and P13, and the inductors are L11, L12, and L13. The series resonators S11, S12, S13, and S14 are connected in series in sequence to form a series branch. The parallel resonators P11, P12, and P13 are first connected in series with the inductors L11, L12, and L13, respectively, and then connected in parallel to the corresponding nodes of the series branches. The parallel branch composed of the parallel resonator P11 and the inductor L11 has one end connected between the series resonators S11 and S12, and the other end is grounded; the parallel branch composed of the parallel resonator P12 and the inductor L12 has one end connected between the series resonators S12 and S13, and the other end is also grounded; the parallel branch composed of the parallel resonator P13 and the inductor L13 has one end connected between the series resonators S13 and S14, and the other end is also grounded. The parallel resonators P11, P12, and P13 of the filter 101 need to be loaded with mass loads so that their parallel resonant frequencies are close to the series resonant frequencies of the series resonators S11, S12, S13, and S14, thereby forming a bandpass filter covering low frequencies, and the inductors L11, L12, and L13 play a role in controlling the transmission zero point of the filter, thereby affecting the out-of-band suppression.

[0034] like Figure 3 As shown, the second filter branch is composed of a filter 201 that can cover high frequencies, a phase-shift network module 211 , and a phase-shift network module 221 . The phase-shift network modules 211 and 221 are connected in series to both ends of the filter 201 , respectively.

[0035] The filter 201 has a circuit topology of a 4-3 ladder structure, which is mainly composed of 4 series resonators, 3 parallel resonators, and 3 inductors. The series resonators include S21, S22, S23, and S24, the parallel resonators include P21, P22, and P23, and the inductors are L21, L22, and L23. The series resonators S21, S22, S23, and S24 are connected in series in sequence to form a series branch, and the parallel resonators P21, P22, and P23 are first connected in series with the inductors L21, L22, and L23, respectively, and then connected in parallel to the corresponding nodes of the series branch. The parallel branch composed of the parallel resonator P21 and the inductor L21 has one end connected between the series resonators S21 and S22, and the other end is grounded; the parallel branch composed of the parallel resonator P22 and the inductor L22 has one end connected between the series resonators S22 and S23, and the other end is also grounded; the parallel branch composed of the parallel resonator P23 and the inductor L23 has one end connected between the series resonators S23 and S24, and the other end is also grounded. The parallel resonators P21, P22, and P23 of the filter 201 need to be loaded with mass loads so that their parallel resonant frequencies are close to the series resonant frequencies of the series resonators S21, S22, S23, and S24, thereby forming a bandpass filter covering high frequencies, and the inductors L21, L22, and L23 play a role in controlling the transmission zero point of the filter, thereby affecting the out-of-band suppression.

[0036] The phase shift network module 211 is composed of a capacitor C1 and two inductors L31 and L32 connected in parallel to the capacitor. In a further embodiment, there is a mutual inductance M1 ( Figure 8 The mutual inductance M1 is formed as shown in FIG. Figure 8 The phase shift network module 221 is composed of a capacitor C2 and two inductors L33 and L34 connected in parallel to the capacitor. In a further embodiment, there is a mutual inductance M2 ( Figure 8 The mutual inductance M2 is exemplarily shown in FIG. Figure 8 The cross-coupling method shown in , or the method of arranging adjacent to each other in the vertical direction, etc.)

[0037] Phase shift network module 211 and phase shift network module 221 are mainly used to adjust the impedance curve of filter 201 in the frequency band adjacent to filter 101, thereby improving the insertion loss within the band. Figure 4 As shown, the solid line is the impedance curve of the second filter branch when the phase shift network module is not added (expressed on the Smith chart), where the AB segment is the frequency range covered by the second filter branch, and the BC segment is the frequency band covered by the adjacent first filter branch. After adding the phase shift network module, the impedance curve of the entire second filter branch becomes Figure 4 The dotted line, where segment A1B1 is the frequency range covered by the second filter branch, and segment B1C1 is the frequency band adjacent to the first filter branch. After passing through the phase shift network module, segment B1C1 is closer to the open end, thereby reducing the impact on the first filter branch, thereby improving the in-band insertion loss (for example, see Figure 5-6 and its related description).

[0038] like Figure 3 As shown, the input ports of the first filter branch and the second filter branch are connected in parallel to the common port 1 to form the input port of the combined filter, and the output ports of the first filter branch and the second filter branch are connected in parallel to the common port 2 to form the output port of the combined filter; the input port of the combined filter is connected in parallel with an inductor L41, and the output port of the combined filter is connected in parallel with an inductor L42.

[0039] As the basis of the present invention Figure 3 As an exemplary embodiment of the scheme, the inventors designed a bandpass filter that can cover the frequency band of 2.49-2.71 GHz. This filter has a large relative bandwidth, which can reach 8.1%. The first filter branch covers 2.49-2.59 GHz, and the second filter branch covers 2.59-2.71 GHz.

[0040] Figure 5 As shown in the insertion loss diagram, the adjacent band (2.2-2.47GHz and 2.75-2.36GHz) suppression is greater than 45dB, while the band covering 1.5-2.2GHz is suppressed by more than 34dB, and the entire filter has a high out-of-band suppression.

[0041] Figure 6 This is a partial enlarged diagram of the filter characteristics covering the 2.49-2.71GHz frequency band. The solid line is the insertion loss when two phase-shift network modules are present, and the dotted line is the insertion loss when the two phase-shift network modules are not present. It can be seen that due to the presence of the two phase-shift network modules, the insertion loss of the center frequency band 2.56-2.61GHz of the filter is within 1.8dB, while when the phase-shift network modules do not exist, the insertion loss of the center frequency band 2.56-2.61GHz deteriorates to 3.3dB. Therefore, the presence of the two phase-shift network modules improves the in-band insertion loss of the filter.

[0042] Figure 7 The corresponding return loss diagram of the above solution is shown in the figure. As shown in the figure, the return losses of the two ports of the filter are both below 20dB.

[0043] Figure 8 For the corresponding Figure 3 Schematic diagram of the bonding wire package form of the duplexer. Figure 8It is a wire bonding package, wherein each BAW resonator of the filter 101 is integrated on the chip 02, each inductor of the filter 101 is integrated on the PCB 01 (corresponding to the package carrier), each BAW resonator of the filter 201 is integrated on the chip 03, each inductor of the filter 201 is integrated on the PCB 01, and the phase shift network module 211 is implemented by the integrated passive device IPD (integrated passive devices) process and integrated on the chip 04, and the phase shift network module 221 is implemented by the integrated passive device IPD (integrated passive devices) process and integrated on the chip 05. The IPD process has the characteristics of high integration, small size, high Q value, etc., and can be well integrated with the BAW resonator. Chips 02, 03, 04, and 05 are then integrated on the PCB 01 by wire bonding.

[0044] However, although not shown, if the space on the chip 3 is large enough (for example, by using a BAW resonator with a reduced size), two phase shift network modules can be directly arranged in the chip 3.

[0045] In addition, although not shown, when the package carrier adopts a LTCC substrate, for example, the phase-shift network module can be directly disposed in the package carrier.

[0046] exist Figure 3 In the embodiment of the present invention, the phase shift network modules are composed of a capacitor and two ground inductors connected in parallel at both ends thereof. Figure 8 As shown, the two grounding inductors also form a mutual inductance. However, the phase-shifting network module is not limited thereto. For example, the two parallel-connected inductors may not form a mutual inductance.

[0047] also, Fig. 9 An alternative form of the phase shift network module is also shown in FIG. Fig. 9 As shown in the left figure, a phase shift network module includes: a capacitor C1 connected between a corresponding port and a filter part; a transmission line device TL32, a first end of the transmission line device TL32 is connected to one end of the capacitor C1, and a second end of the transmission line device TR32 is grounded; and an inductor L31, a first end of the inductor L31 is connected to the other end of the capacitor C1, and a second end of the inductor L31 is grounded. Fig. 9 The right side of the figure shows that the transmission line device TL31 is used to replace Figure 3 Inductor L31 in the phase-shift network module.

[0048] Although not shown, in one embodiment, the phase shift network module includes: a capacitor connected between the corresponding port and the filter part; and a first transmission line device and a second transmission line device, wherein the first ends of the two transmission line devices are respectively connected to the two ends of the capacitor, and the second ends of the two transmission line devices are both grounded.

[0049] It should also be pointed out that, in the present invention, the inductor in the phase-shift network module may be an equivalent inductor device, and the capacitor may be an equivalent capacitor device.

[0050] The above description is made by taking a duplexer or a combined broadband filter having two FBAW filter branches as an example. It should be noted that although the FBAW filter is used as an example for description, the filter of the present invention is not limited to the FBAW filter.

[0051] Accordingly, an embodiment of the present invention also proposes a filter, comprising:

[0052] The filter section has a first filter unit (eg, corresponding to Figure 3 The large rectangular dashed box in the upper middle part), and the second filter unit (for example, may correspond to Figure 3 The large rectangular dotted box in the lower middle part shows it);

[0053] The first port (which may correspond to, for example, Figure 3 port 1 in the example) and a second port (which may correspond to, for example, Figure 3 Port 2 in the filter section is connected between the first port and the second port;

[0054] The first phase-shift network module (eg corresponding to Figure 3 , connected between the second filter unit and the first port; and

[0055] The second phase shift network module (eg corresponding to Figure 3 ), connected between the second filter unit and the second port.

[0056] Based on the above, the present invention proposes a duplexer unit, comprising: a packaging substrate (eg corresponding to Figure 8 PCB01 in); and a high-frequency bandpass filter unit and a low-frequency bandpass filter unit, the two filter units are respectively arranged on a high-frequency bandpass filter chip (for example, see Figure 8 Chip 03 in) and low frequency bandpass filter chip (see for example Figure 8 Chip 02 in the package), a high-frequency band-pass filter chip and a low-frequency band-pass filter chip are packaged on the package carrier and are suitable for being connected to two common ports, wherein: the high-frequency band-pass filter is the second filter unit mentioned above.

[0057] The present invention also relates to a duplexer having the above duplexer unit.

[0058] The embodiments of the present invention also relate to an electronic device, including the above-mentioned filter or duplexer. It should be noted that the electronic device here includes but is not limited to intermediate products such as RF front-ends and filter amplifier modules, as well as terminal products such as mobile phones, WIFI, drones, and smart watches.

[0059] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A filter, comprising: A filter unit including a first filter unit covering a low frequency band and a second filter unit covering a high frequency band; a first port and a second port, the filter section being connected between the first port and the second port; Two ends of the first filter unit are directly connected to the first port and the second port respectively; A first phase shift network module is connected between the second filter unit and the first port; and The second phase shift network module is connected between the second filter unit and the second port; wherein, The first phase-shift network module and the second phase-shift network module both include capacitive components and inductive components.

2. The filter according to claim 1, wherein: The first phase-shift network module is identical to the second phase-shift network module.

3. The filter according to claim 1 or 2, wherein: At least one phase-shift network module comprises: a capacitive device connected between the corresponding port and the second filter unit; and The first inductor and the second inductor, Wherein: the first ends of the two inductors are connected to the two ends of the capacitive device respectively, and the second ends of the two inductors are grounded.

4. The filter according to claim 3, wherein: A mutual inductance is formed between the first inductor and the second inductor.

5. The filter according to claim 1 or 2, wherein: At least one phase-shift network module comprises: a capacitive device connected between the corresponding port and the second filter unit; and The first transmission line device and the second transmission line device, the first ends of the two transmission line devices are respectively connected to the two ends of the capacitive device, and the second ends of the two transmission line devices are both grounded.

6. The filter according to claim 1 or 2, wherein: At least one phase-shift network module comprises: a capacitive device connected between the corresponding port and the second filter unit; a transmission line device, a first end of the transmission line device being connected to one end of the capacitive device and a second end of the transmission line device being grounded; and An inductor, a first end of the inductor is connected to the other end of the capacitive device, and a second end of the inductor is grounded.

7. The filter according to claim 1, wherein: The filter is a thin film bulk acoustic wave filter.

8. A duplexer unit, comprising: Package carrier board; and A high-frequency band-pass filter unit and a low-frequency band-pass filter unit, wherein the two filter units are respectively arranged on the high-frequency band-pass filter chip and the low-frequency band-pass filter chip, the high-frequency band-pass filter chip and the low-frequency band-pass filter chip are packaged on the package carrier board and are suitable for being commonly connected to two common ports. in: The high-frequency band-pass filter unit is the second filter unit of the filter according to any one of claims 1 to 7, and the low-frequency band-pass filter unit is the first filter unit of the filter according to any one of claims 1 to 7; and The first port and the second port are connected to the two common ports, respectively.

9. The duplexer unit according to claim 8, wherein: Each phase-shift network module is disposed on a corresponding phase-shift network module chip; and The phase-shift network module chip, the high-frequency band-pass filter chip and the low-frequency band-pass filter chip are all integrated on the packaging carrier board, and corresponding chips are connected by bonding wires.

10. The duplexer unit according to claim 8, wherein: At least one phase-shifting network module is disposed in the package carrier; or At least one phase shift network module is arranged on the high frequency band pass filter chip.

11. A duplexer, comprising the duplexer unit according to any one of claims 8 to 10.

12. An electronic device, comprising the filter according to any one of claims 1 to 7, or comprising the duplexer unit according to any one of claims 8 to 10.

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