Multiplexer, radio frequency module and electronic equipment
By introducing a capacitor bank parallel resonator into the multiplexer, ensuring that the series frequency of the filter exceeds the passband, the problem of mutual interference between unit filters in the multiplexer is solved, and signal quality and passband loss are improved.
Patent Information
- Application Number
- CN202411372331.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-29
- Publication Date
- 2025-01-10
AI Technical Summary
In multiplexer design, it is particularly important to reduce the mutual interference between the filters of each cell, especially in the high steepness frequency band, to avoid the decline in passband insertion loss and the decrease in signal quality.
Design a multiplexer, including a series branch of the resonator, a parallel resonator and a capacitor bank, by connecting the capacitor bank in the parallel resonator of the target cell filter, ensure that the series resonance frequency of the cell filter where the capacitor is located exceeds the adjacent ones. The passband of the unit filter, thereby preventing signal leakage and mutual interference.
It effectively reduces mutual interference between unit filters and improves signal quality, especially in high steepness signal processing, which significantly improves passband loss, prevents signal leakage and interference between adjacent unit filters.
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Figure CN119298875A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of electronic circuits, and in particular to a multiplexer capable of reducing mutual interference among unit filters, and a radio frequency module and electronic equipment using the multiplexer. Background Art
[0002] A multiplexer, also known as a multiplexer or multiplexer, is an electronic device that allows multiple signals to share the same physical medium (such as an antenna, transmission line or channel) for transmission. In multi-channel communication systems, multiplexers play a key role. They can merge multiple input signals into a single output channel, or separate a single received signal into multiple output signals at the receiving end. This technology is widely used in wireless communications, satellite communications, cable TV networks, fiber optic communications and other fields.
[0003] In the design of a multiplexer, it is necessary to balance the performance of each unit filter and reduce the mutual interference between them. This is particularly important in frequency bands with high steepness requirements, such as the Band25+B66(70) quadplexer. Reducing the mutual interference between each unit filter can reverse the decline in passband insertion loss and thus ensure signal quality.
[0004] How to reduce the mutual interference between the unit filters is one of the technical problems that those skilled in the art need to solve urgently. Summary of the invention
[0005] In view of this, an embodiment of the present invention provides a multiplexer and an electronic device to reduce mutual interference between unit filters.
[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:
[0007] A multiplexer, comprising:
[0008] The first unit filter to the Nth unit filter, wherein N is a positive integer not less than 2;
[0009] Each unit filter includes:
[0010] A resonator series branch, wherein the resonator series branch includes at least two series resonators connected in series with each other, and a first end of the resonator series branch is connected to an antenna port;
[0011] A parallel resonator, wherein the parallel resonator corresponds to the series resonator one by one, a first end of the parallel resonator is connected to an end of the corresponding series resonator away from the antenna port, and a second end of the parallel resonator is grounded;
[0012] A capacitor group, at least one unit filter among the N unit filters serves as a target unit filter, at least one parallel resonator in the target unit filter serves as a target parallel resonator, the capacitor group corresponds to the target parallel resonator one-to-one, and the target parallel resonator is in parallel relationship with the capacitor group.
[0013] Optionally, in the above-mentioned multiplexer, the target unit filter is the second unit filter to the Nth unit filter among the N unit filters.
[0014] Optionally, in the above-mentioned multiplexer, the target parallel resonator includes at least a parallel resonator in the unit filter that is closest to an antenna port.
[0015] Optionally, in the above-mentioned multiplexer, the capacitor group includes at least one capacitor.
[0016] Optionally, in the above multiplexer, the capacity of the capacitor is proportional to the interference amount, and the interference amount is used to indicate the degree of interference between the unit filter where the capacitor is located and an adjacent unit filter.
[0017] Optionally, in the above-mentioned multiplexer, the capacitor is an interdigital capacitor.
[0018] Optionally, in the above-mentioned multiplexer, the capacitor is a capacitor with adjustable capacity.
[0019] A radio frequency module, comprising any one of the multiplexers described above
[0020] An electronic device comprises any one of the multiplexers mentioned above.
[0021] Optionally, the electronic device is a communication device, a broadcasting device or a data transmission device.
[0022] Based on the above technical solution, the above-mentioned multiplexer provided in an embodiment of the present invention includes a resonator series branch, a parallel resonator and a capacitor group, one end of the parallel resonator is connected to the end of the corresponding series resonator in the resonator series branch away from the antenna port, and the other end is grounded, the capacitor group is connected in parallel with the target parallel resonator of the target unit filter in the N unit filters one by one, and the target parallel resonator and the capacitor group are in a parallel relationship, and a capacitor group is connected in parallel with the target parallel resonator in the target unit filter. When the multiplexer is running, due to the presence of the capacitor group, the series resonant frequency of the unit filter where the capacitor group is located will exceed the passband of its adjacent unit filter, thereby preventing the signal on the adjacent unit filter from leaking from the unit filter, thereby preventing mutual interference between adjacent unit filters. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.
[0024] Figure 1 It is a schematic diagram of the structure of a quadplexer in the prior art;
[0025] Figure 2 A schematic diagram of the circuit structure of a multiplexer disclosed in an embodiment of the present application;
[0026] Figure 3 A schematic diagram of the structure of a quadplexer disclosed in an embodiment of the present application;
[0027] Figure 4 A schematic diagram showing a loss comparison of a unit filter B66TX of a quadplexer disclosed in an embodiment of the present application after adding a capacitor;
[0028] Figure 5 A schematic diagram showing a loss comparison of a unit filter B25TX of a quadplexer disclosed in an embodiment of the present application after adding a capacitor;
[0029] Figure 6 A schematic diagram showing a loss comparison of a unit filter B25TX of a quadplexer disclosed in an embodiment of the present application after adding a capacitor;
[0030] Figure 7 A schematic diagram showing a loss comparison of a unit filter B25RX of a quadplexer disclosed in an embodiment of the present application after adding a capacitor;
[0031] Figure 8 A schematic diagram showing a loss comparison of a unit filter B25RX of a quadplexer disclosed in an embodiment of the present application after adding a capacitor;
[0032] Fig. 9 This is a schematic diagram comparing the losses of the unit filter B66RX of the quadplexer disclosed in the embodiment of the present application after adding capacitors. DETAILED DESCRIPTION
[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0034] Figure 1The circuit structure diagram of the quadplexer is a Band25+B66(70) quadplexer. With reference to the antenna port (Ant), the first resonator in the four unit filters B66TX\B25TX\B25RX\B66RX (such as X refers to s1) is recorded as the first series resonator s1 (B66T s1\B25T s1\B25R s1\B66R s1), followed by the first parallel resonator p1 (such as B66T p1\B25T p1\B25R p1\B66R p1). Subsequently, according to the filter frequency band attributes and index requirements, the nth series resonator Sn and the mth parallel resonator Pm will be added, and DMS will be used in the two RX filters. The detailed circuit structure of the quadplexer can be found in the prior art, and this application does not introduce it in detail.
[0035] On the basis of the existing multiplexer, the applicant improved the circuit structure of the existing multiplexer and obtained a multiplexer capable of reducing the mutual interference of unit filters.
[0036] See also Figure 2 The multiplexer disclosed in the embodiment of the present application includes a first unit filter 101 to an Nth unit filter 10n, wherein N is a positive integer not less than 2, and N can be used to characterize the type of the multiplexer. For example, when N is 2, the multiplexer is specifically a duplexer, when N is 3, the multiplexer is specifically a triplexer, and when N is 4, the multiplexer is specifically a quadplexer;
[0037] The structures of the unit filters in the multiplexer are the same, see Figure 2 , each unit filter includes: a resonator series branch, a parallel resonator p and a capacitor group C;
[0038] Regarding the resonator series branch, the resonator series branch includes at least two series resonators s connected in series with each other, and a first end of the resonator series branch is connected to the antenna port Ant;
[0039] Regarding the parallel resonator p, the parallel resonator p corresponds to the series resonator s one by one, the first end of the parallel resonator p is connected to an end of the series resonator s corresponding to the parallel resonator p that is away from the antenna port Ant, and the second end of the parallel resonator p is grounded;
[0040] A capacitor group C, at least one unit filter s among the N unit filters serves as a target unit filter D, at least one parallel resonator p in the target unit filter D serves as a target parallel resonator B, the capacitor group C corresponds one-to-one to the target parallel resonator B, and the target parallel resonator B is in a parallel relationship with the capacitor group C.
[0041] The first unit filter 101 to the Nth unit filter 10n are distributed in parallel on the circuit board and arranged in parallel, wherein the second unit filter 102 is adjacent to the first unit filter 101, the third unit filter 103 is adjacent to the second unit filter 102... The Nth unit filter 10n is adjacent to the N-1th unit filter 10n-1. There is mutual interference between adjacent unit filters.
[0042] In order to solve the mutual interference between adjacent unit filters, the present application determines some target unit filters D from the N unit filters, and further determines some target parallel resonators B from the parallel resonators in the target unit filters D, and connects a capacitor group C in parallel to the target parallel resonators B in these target unit filters D. The capacitor group may include at least one capacitor, and the type of the capacitor can be selected according to the relevant requirements, for example, it can be a finger capacitor. When the capacitor group contains only one capacitor, the capacitor is connected in parallel with the target parallel resonator B. When the capacitor group contains multiple capacitors, these capacitors are connected in series or in parallel to form an equivalent capacitor, and the equivalent capacitor is connected in parallel with the target parallel resonator B.
[0043] When the multiplexer is running, due to the presence of the capacitor group, the series resonant frequency of the unit filter where the capacitor group is located will exceed the passband of its adjacent unit filter, thereby preventing the signal on the adjacent unit filter from leaking from the unit filter, thereby preventing mutual interference between adjacent unit filters.
[0044] More vividly: Figure 1 In the example, the series resonant frequency of the first parallel resonator B25Tp1 of B25Tx is B25Tp1_fs, which is lower than the right side frequency of the passband of B66Tx, 1780MHz. The so-called series resonant frequency means that the impedance approaches 0, so part of the signal of B66Tx in the prior art will leak from the first parallel resonator B25Tp1 of B25Tx. Figure 3 When a capacitor group is introduced into the parallel resonator B25Tp1, the series resonant frequency of the parallel resonator B25Tp1 will change. At this time, the series resonant frequency B25Tp1_fs will exceed the passband of B66Tx, thereby increasing the passband loss of B66Tx. Some signals of B66Tx will not leak from the first parallel resonator B25Tp1 of B25Tx, thereby preventing mutual interference between B66Tx and B25Tx.
[0045] In the technical solution disclosed in this embodiment, which unit filters in the multiplexer are specifically selected as the target unit filter D can be selected according to user needs. In this embodiment, all unit filters in the multiplexer can be used as the target unit filter D, or the second unit filter to the Nth unit filter in the target unit filter D can be used as the target unit filter D, or the target unit filter D can be selected from the multiplexer in a mutually spaced manner, for example, the first unit filter, the third unit filter, the fifth unit filter...the m+1th unit filter are used as the target unit filter D, where m is an even number, or the second unit filter, the fourth unit filter, the sixth unit filter...the mth unit filter are used as the target unit filter D.
[0046] In this embodiment, at least one parallel resonator can be selected from the multiple parallel resonators in the target parallel resonator B as the target parallel resonator in this application according to the requirements involved. For example, all parallel resonators in the parallel resonator can be used as target unit filters. Of course, for the sake of design cost and design effect, in the technical solution disclosed in the embodiment of this application, the target parallel resonator at least includes the parallel resonator closest to the antenna port in the unit filter. Even the target parallel resonator refers to the parallel resonator closest to the antenna port in the unit filter. When the parallel resonator closest to the antenna port is connected to a capacitor group in parallel, the anti-interference effect of the multiplexer developed in this application can be optimized.
[0047] In this embodiment, in order to achieve the best anti-interference effect of the multiplexer, the design parameters of the capacitor need to be optimized to improve the anti-interference effect. The setting parameters of the capacitor may refer to the capacity of the capacitor. In this embodiment, the capacity of the capacitor depends on the amount of interference of one unit filter on another unit filter in the designed multiplexer. For example, Figure 1In the quadplexer shown, the passband of the unit filter B25Tx is 1850MHz~1915MHz, the passband of the unit filter B66Tx is 1695MHz~1780MHz, and the series resonant frequency B25Tp1_fs of the first parallel resonator of the unit filter B25Tx is less than the right side frequency 1780MHz of the passband of the unit filter B66Tx. When the difference between the right side frequency 1780 MHz of the passband and the series resonant frequency B25Tp1_fs of the first parallel resonator of the unit filter B25Tx is larger, the interference amount is larger. At this time, a capacitor with a larger capacitance is required to eliminate this difference, and finally make B25Tp1_fs greater than 1780MHz. Therefore, in this embodiment, the capacity of the capacitor is proportional to the interference amount, and the interference amount is used to indicate the interference degree between the unit filter where the capacitor is located and the adjacent unit filter.
[0048] Furthermore, as the aging degree of the multiplexer continues to increase, as the device ages, the capacitance of the capacitor or the above-mentioned B25Tp1_fs and the value of the frequency on the right side of the passband may change, thereby reducing the anti-interference performance of the multiplexer. Considering these circumstances, the capacitor can be a capacitor with adjustable capacitance. When the anti-interference performance of the multiplexer is reduced, the capacitance of the capacitor can be fine-tuned to further improve the anti-interference performance of the multiplexer.
[0049] by Figure 1 Based on the quadplexer shown, see Figure 3 , take B25TX\B25RX\B66RX as the target unit filter D, take the parallel resonator B25T p1\B25R p1\B66R p1 closest to the specific antenna interface Ant as the target parallel resonator B, configure a capacitor 25TXC1, B25RXC1, B66RXC1 for these target parallel resonators B respectively, and then perform a performance test on the quadplexer.
[0050] See also Figure 4 , Figure 4 The curve L1 in the figure is the loss of B66TX before the capacitor is introduced, and the curve L2 is the loss of B66TX before the capacitor is introduced. Figure 4 By comparing the curve L1 with the curve L2 in FIG. 1 , it is found that the introduction of the capacitor B25TC1 effectively reduces the interference of the unit filter B25TX on the right side of the passband of the unit filter B66TX, thereby improving the loss of the unit filter B66TX. Figure 4 As shown, compared with the L1 curve without the capacitor B25TC1, the L2 curve after the capacitor B25TC1 is introduced can be seen to improve the loss on the right side of the passband of the unit filter B66TX. For further information, see Figure 5 , Figure 5 L11 is the loss of the unit filter B66TX when no capacitor is introduced, and L21 is the loss of the unit filter B66TX when a capacitor is introduced. Figure 5 It can be seen that after the introduction of capacitor B25TC1, the performance of the unit filter B25TX is basically unaffected.
[0051] See also Figure 6 , Figure 6 The curve L3 in the figure is the loss of B25TX before the capacitor is introduced, and the curve L4 is the loss of B25TX before the capacitor is introduced. Figure 6 By comparing the curve L3 and the curve L4 in FIG. 1 , it is found that after the introduction of the capacitor B25RC1, the interference of the unit filter B25RX on the right side of the passband of the unit filter B25TX is effectively reduced, thereby improving the loss of the unit filter B25TX. Figure 6 As shown, compared with the L3 curve without the capacitor B25RC1, the L4 curve after the capacitor B25RC1 is introduced can be seen to improve the loss on the right side of the passband of the unit filter B25TX. Further, see Figure 7 , Figure 7 L41 in is the loss of the unit filter B25RX when no capacitor is introduced, and L41 is the loss of the unit filter B25RX when the capacitor is introduced. Figure 7 It can be seen that after the introduction of capacitor B25RC1, the performance of the unit filter B25RX is basically unaffected.
[0052] See also Figure 8 , Figure 8 The curve L5 in the figure is the loss of B25RX loss before the capacitor is introduced, and the curve L6 is the loss of B25RX loss before the capacitor is introduced. Figure 8 By comparing the curve L5 with the curve L6 in FIG. 1 , it is found that the introduction of the capacitor B66RXC1 effectively reduces the interference of the unit filter B66RX on the right side of the passband of the unit filter B25RX, thereby improving the loss of the unit filter B25RX. Figure 8 As shown, compared with the L5 curve without the capacitor B66RC1, the L6 curve after the capacitor B66RC1 is introduced can be seen to improve the loss on the right side of the passband of the unit filter B25RX. Further, see Fig. 9 , Fig. 9 L51 is the loss of the unit filter B66RX when no capacitor is introduced, and L61 is the loss of the unit filter B66RX when a capacitor is introduced. Fig. 9 It can be seen that after the introduction of capacitor B66RC1, the performance of the unit filter B66RX is basically unaffected.
[0053] It should be further pointed out that the scheme disclosed in the present invention is particularly effective for unit filters that are prone to high steepness signals during signal processing. For example, when processing multi-band (such as Band 25) antennas or filters, in order to maximize the loss of the unit filter B25RX at 1930MHz, it is often necessary to sacrifice the loss of B25TX. Because the parallel resonant frequency of the parallel resonator in the unit filter B25RX needs to act within the passband of B25RX, and is limited by the extremely small TX\RX band gap (15MHz) of Band25 (referring to the frequency interval (or bandwidth interval, band interval) between the transmit (TX) band and the receive (RX) band in the Band 25 band is very small, only 15MHz. The "bandgap" here refers to the blank area or interval between two adjacent frequency bands, which ensures that the signals do not interfere with each other during transmission and reception), the series resonant frequency of the parallel resonator will naturally act on the right side of the passband (1850MHz-1915MHz) of B25TX, causing pits or spikes in the passband. The present application can perfectly solve this problem by configuring a capacitor for the target unit filter D.
[0054] A radio frequency module, comprising a multiplexer disclosed in any one of the above embodiments. The radio frequency module may be a FEMiD (Front-End Module integrated Duplexer), a PAMiD (Power Amplifier Module integrated Duplexer), a L-PAMiD (LNA-Power Amplifier Module integrated Duplexer), or other types of radio frequency modules.
[0055] An electronic device, comprising any one of the above-mentioned radio frequency modules. The electronic device may be a communication device, a broadcasting device or a data transmission device.
[0056] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.
[0057] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc., mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, without contradiction.
[0058] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.
[0059] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.
[0060] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A multiplexer, characterized in that: include: The first unit filter to the Nth unit filter, wherein N is a positive integer not less than 2; Each unit filter includes: A resonator series branch, wherein the resonator series branch includes at least two series resonators connected in series with each other, and a first end of the resonator series branch is connected to an antenna port; A parallel resonator, wherein the parallel resonator corresponds to the series resonator one by one, a first end of the parallel resonator is connected to an end of the corresponding series resonator away from the antenna port, and a second end of the parallel resonator is grounded; A capacitor group, at least one unit filter among the N unit filters serves as a target unit filter, at least one parallel resonator in the target unit filter serves as a target parallel resonator, the capacitor group corresponds to the target parallel resonator one-to-one, and the target parallel resonator is in parallel relationship with the capacitor group.
2. The multiplexer according to claim 1, characterized in that: The target unit filter is the second unit filter to the Nth unit filter among the N unit filters.
3. The multiplexer according to claim 1, characterized in that: The target parallel resonator includes at least a parallel resonator closest to an antenna port in the unit filter.
4. The multiplexer according to claim 1, wherein: The capacitor bank includes at least one capacitor.
5. The multiplexer according to claim 4, characterized in that: The capacity of the capacitor is proportional to the interference amount, and the interference amount is used to indicate the interference degree between the unit filter where the capacitor is located and an adjacent unit filter.
6. The multiplexer according to claim 4, characterized in that: The capacitor is an interdigital capacitor.
7. The multiplexer according to claim 5, characterized in that: The capacitor is a capacitor with adjustable capacity.
8. A radio frequency module, characterized in that: A multiplexer comprising any one of claims 1 to 7.
9. An electronic device, characterized in that: Including the radio frequency module described in claim 8.
10. The electronic device according to claim 9, characterized in that: The electronic device is a communication device, a broadcasting device or a data transmission device.