Filtering device and communication equipment

Abstract

The utility model discloses a filtering device and communication equipment. The filtering device comprises an input end, an output end, a filtering circuit and an isolating circuit, the input end is electrically connected with an antenna, the input end is used for receiving a receiving signal from the antenna, the input end inputs the received receiving signal of the antenna into the filtering circuit and the isolating circuit, the filtering circuit is electrically connected with the output end, and the isolating circuit is electrically connected with the output end. The filter circuit is used for filtering a received signal of the antenna to obtain a first signal, the isolation circuit is electrically connected with a load and is used for filtering the received signal of the antenna to obtain a second signal, and the first signal is a frequency signal needing to be output by the filter device; the second signal is a frequency signal having a frequency different from that of the first signal in the received signal of the antenna. According to the invention, the isolation circuit is arranged to filter out the second signal and absorb the second signal through the load, so that the signal reflection of the second signal to the front-end circuit is reduced, and the interference of the second signal to the first signal is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic devices, and in particular to a filtering device and a communication device. BACKGROUND

[0002] With the development of communication technology, the number of communication frequency bands is also gradually increasing, for example, from 4 frequency bands in the 2G era to more than 50 frequency bands in the 5G era. In order to improve the compatibility of communication devices for different communication systems, the demand for filters in communication systems has increased significantly, thereby promoting the large-scale growth of the filter market.

[0003] In the related art, the circuit part between the antenna and the baseband can be referred to as a front-end circuit, which can process the reception and transmission of signals. The communication system can receive signals through the antenna, and the filter can selectively pass certain specific frequency range signals, filter out the signals required to be output by the communication system, and at the same time, the filter can block or attenuate the signals that are not required in the communication system. We can consider the signals selectively passed by the filter as the signals required by the communication system. In some cases, if the signals that are not required in the communication system fail to be processed or attenuated in time, these signals can interfere with the signals required by the system, thereby affecting the effective transmission of the signals required by the system. In some cases, the signals that are not required in the communication system, that is, the signals that cannot pass through the filter and fail to be processed in time, can cause signal reflection on the front-end circuit or the electronic devices in the front-end circuit, that is, part of the energy of the signals that are not required in the communication system can return along the original path, thereby affecting the overall stability of the front-end circuit.

[0004] Therefore, how to better process the signals that are not required in the communication system to reduce the interference with the signals required by the communication system and reduce the reflection phenomenon caused by the signals that are not required in the communication system, which affects the stability of the front-end circuit, is an urgent problem to be solved. Practical new type content

[0005] Therefore, the embodiments of the present application are committed to providing a filtering device and a communication device.

[0006] In a first aspect, a filter device is provided, comprising: an input end, an output end, a filter circuit and an isolation circuit, the input end being electrically connected to an antenna, the input end being configured to receive a received signal from the antenna, the input end being configured to input the received signal from the antenna to the filter circuit and the isolation circuit, the filter circuit being electrically connected to the output end, the filter circuit being configured to filter the received signal from the antenna to obtain a first signal, the isolation circuit being electrically connected to a load, the isolation circuit being configured to filter the received signal from the antenna to obtain a second signal, wherein the first signal is a frequency signal required to be output by the filter device, and the second signal is a frequency signal different from the first signal in the received signal from the antenna.

[0007] According to the first aspect, the isolation circuit is a surface acoustic wave isolation circuit, the isolation circuit comprises a plurality of IDTs, the isolation circuit comprises N sub-isolation circuits, the N sub-isolation circuits are connected in parallel, each sub-isolation circuit is configured to filter out the second signal belonging to a sub-isolation frequency range, each sub-isolation circuit corresponds to a sub-isolation frequency range, and N is a positive integer.

[0008] According to the first aspect, or any one of the implementation forms of the first aspect, each of the N sub-isolation circuits is connected to the same load, or the N sub-isolation circuits are connected to N loads, or part of the N sub-isolation circuits are connected to the same load.

[0009] According to the first aspect, or any one of the implementation forms of the first aspect, the filter circuit is a surface acoustic wave filter circuit, the filter circuit comprises a plurality of IDTs, the isolation circuit comprises a plurality of IDTs, and the filter circuit comprises a plurality of IDTs of a first type, the first type comprising one or more of: a substrate of the IDT, and a metal strip of the IDT.

[0010] According to the first aspect, or any one of the implementation forms of the first aspect, the filter circuit comprises M sub-filter circuits, the M sub-filter circuits are connected in parallel, each sub-filter circuit is configured to filter out the first signal belonging to a sub-filter frequency range, each sub-filter circuit corresponds to a sub-filter frequency range, and M is a positive integer.

[0011] According to the first aspect, or any one of the implementation forms of the first aspect, the filter circuit and / or the isolation circuit each comprises a plurality of IDTs, and in the filter circuit and / or the isolation circuit, an IDT closest to the antenna has an area greater than that of other IDTs.

[0012] According to the first aspect, or any one of the possible implementation manners of the first aspect, the IDT closest to the antenna end is a first IDT, and the other IDT is a second IDT, the first IDT comprises a plurality of serially connected sub-IDTs, the number of reflection gratings of the first IDT is the same as the number of reflection gratings of the second IDT, the number of interdigital fingers of the sub-IDT is greater than or equal to the number of interdigital fingers of the second IDT, and / or the aperture length of the sub-IDT is greater than or equal to the aperture length of the second IDT.

[0013] According to the first aspect, or any one of the possible implementation manners of the first aspect, the plurality of serially connected sub-IDTs comprises a first sub-IDT, the aperture area of the second IDT multiplied by the number of interdigital fingers of the second IDT multiplied by a first number is equal to the aperture area of the first sub-IDT, the interdigital finger width of the second IDT multiplied by the distance between adjacent interdigital fingers of the second IDT multiplied by the interdigital finger length of the second IDT is equal to the aperture area of the second IDT, and the first number is related to the number of sub-IDTs included in the first IDT.

[0014] According to the first aspect, or any one of the possible implementation manners of the first aspect, the filter device is arranged in a communication system, and the load comprises a load of the communication system.

[0015] According to the first aspect, or any one of the possible implementation manners of the first aspect, according to the signal power of the received signal of the antenna, the filter circuit and the isolation circuit adopt a T-type filter circuit and / or a dual-mode surface acoustic wave filter circuit.

[0016] In a second aspect, the application provides a communication device, which can comprise the filter device of the first aspect or any one of the possible implementation manners of the first aspect.

[0017] The application can filter out a second signal different from the first signal from the received signal of the antenna by arranging the isolation circuit, and absorb the second signal through the load, thereby reducing the signal reflection of the second signal on the front-end circuit, and also reducing the signal interference of the second signal on the first signal, and further improving the overall performance of the communication system. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A filter device structure schematic diagram provided for an embodiment of the application.

[0019] Figure 2 Another filter device structure schematic diagram provided for an embodiment of the application.

[0020] Figure 3 Another filter device structure schematic diagram provided for an embodiment of the application.

[0021] Figure 4 A filter device provided for an embodiment of the application comprises Figure 3The communication system structure diagram of the filter device.

[0022] Figure 5 For Figure 3 The test result diagram of the filter device shown.

[0023] Figure 6 For Figure 3 The circuit layout distribution diagram corresponding to the filter device shown. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art based on the present application belong to the scope of protection of the present application.

[0025] With the development of communication technology, the number of communication frequency bands is also gradually increasing, for example, from 4 frequency bands in the 2G era to more than 50 frequency bands in the 5G era. In order to improve the compatibility of communication equipment to different communication systems, the demand for filters in communication systems has increased significantly, thereby promoting the large-scale growth of the filter market. Filter technology includes the application of new filter technology, performance improvement, the rise of digital filter technology and the innovation of production process to meet the demand of high-speed data transmission and complex signal processing, which promotes the progress and application of filter technology in the field of communication.

[0026] In the prior art, according to different needs of communication systems, filters can be divided into different filter types according to different needs. For example, filters can be classified according to the working principle of the filter, the circuit structure, the filter type and the manufacturing field, etc.

[0027] Several commonly used filters will be introduced below.

[0028] surface acoustic wave (SAW) SAW) filter

[0029] SAW filter is obtained according to the working principle of the filter. SAW filter is a specific type of acoustic wave filter, and acoustic surface wave filter utilizes the characteristics of acoustic waves propagating along the surface of the medium, which are called acoustic surface waves. The radio frequency filter widely used in current wireless communication terminals is acoustic surface wave filter, which is responsible for receiving and transmitting radio frequency signals of the channel, and outputs specific frequency signals in the input multiple radio frequency signals. Due to the advent of 5G communication, acoustic surface wave filter is required to work at a higher frequency.

[0030] The resonator is a key component in a SAW filter, used to achieve specific frequency selective functions. In some SAW filters, an interdigital transducer (IDT) can also be used as a resonator, which can convert electrical energy into acoustic energy to excite acoustic surface waves on a piezoelectric substrate. The frequency characteristics, excitation strength of acoustic surface waves, and finger spacing of the IDT have important influences on the performance of the acoustic surface wave filter.

[0031] SAW wave filters have the advantages of small transmission loss, good electromagnetic interference (EMI) performance, high reliability, and small and light device size, and therefore are widely used in mobile communication terminal products.

[0032] Dual mode surface acoustic wave (dual mode SAW, DMS) Filter

[0033] A dual-mode surface acoustic wave filter is a special type of SAW filter. A DMS filter can be constructed by setting an IDT between gratings, and a wide operating bandwidth can be achieved by combining various resonance modes. The DMS filter can be coupled in the longitudinal direction by two identical resonance modes, thereby achieving low insertion loss and good out-of-band suppression characteristics. Therefore, the loss of the signal passing through the DMS filter is small, which helps to receive a signal with small power.

[0034] T-type filter

[0035] A T-type filter is an electronic filter that includes two inductors and a capacitor. This structure makes it more stable and efficient when handling high-power signals. The working principle of the T filter is to achieve filtering effect through impedance matching and frequency selection. Therefore, this filter is characterized by high impedance at both ends, which makes it less likely to have a "ringing" phenomenon in the switching circuit, thereby improving the stability of the circuit. The T filter can match the impedance on both sides by correctly selecting the element value to maximize the power transmission between the active stage, the switch, and the antenna. This impedance matching capability is crucial for the reception and processing of high-power signals, as it can reduce signal loss and improve signal transmission efficiency.

[0036] In the related art, the circuit part between the antenna and the baseband can be referred to as a front-end circuit, and the front-end circuit can process the reception and transmission of signals. The communication system can receive signals through the antenna, and the frequency range of the signals received by the antenna is related to the bandwidth of the antenna. Generally, the frequency band received by the antenna is relatively wide, and the signals in the frequency band include the signals required by the communication system and the signals not required by the communication system. The filter can selectively pass the signals in a certain specific frequency range, filter out the signals required to be output by the communication system, and at the same time, the filter can also block or attenuate the signals not required to be output by the communication system. The filter plays a crucial role in the communication system and can improve the signal quality and the overall performance of the communication system. In the related art, the signals selectively passed by the filter in a certain specific frequency range can be referred to as useful signals, and can also be understood as the signals required by the communication system. At the same time, the signals blocked by the filter or the signals not required by the communication system can be referred to as useless signals.

[0037] In some cases, if the signals not required by the communication system cannot be processed or attenuated in time, these signals can interfere with the signals required by the communication system, thereby affecting the effective transmission of the signals required by the system. In some cases, the signals not required by the communication system cannot pass through the filter and cannot be processed in time, and these signals can reflect signals on the front-end circuit or the electronic devices in the front-end circuit, that is, part of the energy of the signals not required by the communication system can return along the original path, thereby affecting the overall stability of the front-end circuit.

[0038] In the related art, in order to ensure that the receive / transmit channels do not interfere with each other and at the same time play the role of isolation of the front-end circuit and the rear-end circuit, an isolator can be added to the electronic device. The isolator can cut off the direct connection between the input part of the circuit and the output part of the circuit, avoid interference from mixing into the output signal, and also make the useful signals pass through the circuit unobstructed. The isolator can completely isolate the input part and the output part of the circuit in an electrical manner, so that the front-end circuit is not affected by the signals reflected by the rear-end circuit and blocked by the filter, thereby achieving the purpose of protecting the system and improving the stability and reliability of the system.

[0039] However, the traditional isolators on the market are relatively large, for example, the size of the surface-mounted isolator is 10.3mm x 7.5mm x 2.5mm, and the substrates of other surface-mounted isolators are also at the level of mm. Therefore, when the design size of the communication module is required to be smaller and smaller, the size of the traditional isolator cannot meet the demand of miniaturization of the communication module.

[0040] Therefore, how to better process the signals not required by the communication system to reduce the interference with the signals required by the communication system and reduce the reflection phenomenon caused by the signals not required by the communication system and affect the stability of the front-end circuit is an urgent problem to be solved.

[0041] To solve the above problems, the application provides a filtering device, which can set an isolation circuit, filter out a second signal (which can be understood as a signal that the communication system does not need) with a signal frequency different from a first signal (which can be understood as a signal that the communication system needs) in the receiving signal of the antenna, and absorb the second signal through a load, thereby reducing the signal reflection of the second signal on the front-end circuit, and also reducing the signal interference of the second signal on the first signal, and further improving the overall performance of the communication system.

[0042] Figure 1 It is a structural example of a filtering device provided by the embodiment of the application, which has solved the above problems.

[0043] Figure 1 The device 100 shown can include an input end 110, an output end 140, a filtering circuit 120, and an isolation circuit 130.

[0044] The input end 110 can be electrically connected with the antenna, and the input end 110 can be used to receive the receiving signal from the antenna.

[0045] In some embodiments, when the antenna is normally working, the received signal is within a certain frequency range. According to different functional requirements of the communication system, the antenna can be divided into different types according to different frequency ranges of the received signal of the antenna. For example, a low-frequency antenna can receive a long-wave or low-frequency signal usually between 30 kHz and 300 kHz, a medium-frequency antenna can receive a short-wave and medium-frequency signal usually between 300 kHz and 3 MHz, and a high-frequency antenna can receive a short-wave or high-frequency signal usually between 3 MHz and 30 MHz.

[0046] It can be understood that, based on the functional requirements of the communication system, the receiving signal of the antenna received by the input end 110 can be a signal within a certain frequency range. Alternatively, the frequency range depends not only on the functional requirements of the communication system, but also on the size design and structure design of the antenna.

[0047] In some embodiments, the station site resources of the existing base station can be utilized, for example, a 5G base station antenna can be integrated and designed with a traditional 2G / 3G / 4G base station antenna to realize multi-band coverage. Therefore, the receiving signal of the antenna can also include the frequency requirements of the multi-functional modules in the communication system.

[0048] The input end 110 can input the receiving signal of the antenna into the filtering circuit 120 and the isolation circuit 130 in the filtering device 100.

[0049] In some embodiments, the filter circuit 120 and the isolation circuit 130 can be connected in parallel. For example, the first end of the filter circuit 120 is electrically connected to the input end 110, and the first end of the isolation circuit 130 is electrically connected to the input end 110.

[0050] When the input end 110 receives the receiving signal of the antenna, the receiving signal can be input into the filter circuit 120 and the isolation circuit 130.

[0051] In some embodiments, the receiving signal of the antenna can be filtered by the filter circuit 120 to obtain a first signal.

[0052] For example, the first signal can be a frequency signal required to be output by the filtering device 100. For example, the receiving signal of the antenna can include signals in a certain frequency range, and the frequency range of the first signal belongs to the frequency range of the receiving signal of the antenna.

[0053] For example, the first signal can be a signal required by a communication system, such as a useful signal described above, which can be a signal in a certain frequency range. For example, when the filter circuit is a high-pass filter circuit, a high-frequency signal can be filtered out, and the high-frequency signal can be the first signal.

[0054] In some embodiments, the filter circuit 120 is electrically connected to the output end 140. When the filter circuit 120 filters out the first signal, the first signal can be input into other circuit modules of the communication system through the output end 140, and the signal processing of other modules can continue.

[0055] In some embodiments, the filter circuit 120 can be a surface acoustic wave filter circuit, and the filter circuit 120 can include a plurality of interdigital transducers. As shown in Figure 2 For example, the filter circuit 120 can be composed by connecting IDT1201, IDT1202, …, IDT1205 in series and IDT1206, …, IDT1209 in parallel, which can filter out the first signal.

[0056] In some embodiments, the filter circuit 120 can include M sub-filter circuits connected in parallel. The sub-filter circuit can be used to filter out a second signal belonging to a sub-filter frequency range. The sub-filter circuit can correspond to the sub-filter frequency range one by one, where M is a positive integer.

[0057] In some embodiments, when the frequency range of the first signal belongs to two discontinuous frequency regions, M sub-filter circuits can be set to accurately filter the first signal, or when the frequency range of the first signal is too large, M sub-filter circuits can also be set to more accurately filter the first signal, to improve the signal quality and strength of the filtered first signal, and improve the overall performance of the communication system.

[0058] Exemplarily, Figure 3 Another filter device structure schematic diagram provided by the embodiment of the application. Figure 4 A possible filter device provided by the embodiment of the application includes Figure 3 A communication system structure schematic diagram of the filter device. Exemplarily, Figure 4 The first filter in the communication system can be the filter device in the embodiment of the application, the second filter can also be the filter device in the embodiment of the application, and the first filter and the second filter can both be the filter device in the embodiment of the application.

[0059] When M is equal to 2, the filter circuit 120 can include two sub-filter circuits. As Figure 3 The sub-filter circuit 3210 and the sub-filter circuit 3220 shown in the filter circuit 120. The sub-filter circuit 3210 can correspond to a sub-filter frequency range of 1710-1780MHz, and the sub-filter circuit 3220 can correspond to a sub-filter frequency range of 1850-1910MHz.

[0060] In some embodiments, the received signal of the antenna can be filtered by the isolation circuit 130 to obtain a second signal.

[0061] Exemplarily, the second signal can be a signal that needs to be filtered out by the filter device, and it can also be understood that the second signal can be a signal different from the first signal in frequency in the received signal of the antenna. For example, when the antenna is normally working, the received signal can be within a certain frequency range based on the communication demand of the communication system. Therefore, after the frequency range of the first signal is determined, the frequency range of the second signal can be determined according to the frequency range of the received signal of the antenna. For example, the frequency range of the received signal of the antenna is 1710-1880MHz, and the frequency range of the first signal is 1710-1780MHz, then the second signal can be 1780-1889MHz.

[0062] Exemplarily, the second signal can be the useless signal described above, and the second signal can be a signal that is not needed by the communication system.

[0063] In some embodiments, the isolation circuit 130 is electrically connected with a load. After the filter circuit 120 filters out the second signal, the second signal can be absorbed by the load, thereby reducing the signal reflection of the second signal to the front-end circuit, and reducing the signal interference of the second signal to the first signal.

[0064] In some embodiments, the isolation circuit 130 can be a surface acoustic wave filter circuit, and the isolation circuit 130 can include a plurality of IDTs. As shown in Figure 2 the isolation circuit 130 can include a plurality of IDTs, and the plurality of IDTs can be connected in series and in parallel. For example, the IDT 1301, the IDT 1302, and the IDT 1303 can be connected in parallel, and the IDT 1304 and the IDT 1305 can be connected in parallel, to form the isolation circuit 130 that can filter out the second signal.

[0065] In some embodiments, the isolation circuit 130 can include N sub-isolation circuits, and the N sub-isolation circuits can be connected in parallel. The sub-isolation circuit can be used to filter out the second signal belonging to a sub-isolation frequency range. The sub-isolation circuit can correspond to the sub-isolation frequency range one-to-one, where N is a positive integer.

[0066] For example, when N = 2, the isolation circuit 130 can include two sub-isolation circuits. As shown in Figure 3 sub-isolation circuit 3310 and the sub-isolation circuit 3320 in FIG. 13B. The sub-isolation circuit 3310 can correspond to a sub-isolation frequency range of 1930-2020 MHz, and the sub-isolation circuit 3320 can correspond to a sub-isolation frequency range of 2110-2210 MHz.

[0067] In some embodiments, when the range of the second signal belongs to two discontinuous frequency regions, N sub-isolation circuits can be set to accurately filter out the second signal, or when the frequency range of the second signal is too large, N sub-isolation circuits can also be set to more accurately filter out the second signal, to improve the signal quality and strength of the filtered second signal, and to improve the overall performance of the communication system.

[0068] In some embodiments, when the isolation circuit includes N sub-isolation circuits, and the frequency distance between the second signals filtered out by each sub-isolation circuit through the corresponding sub-isolation frequency range is relatively close, then each sub-isolation circuit in the N sub-isolation circuits can be connected with the same load. As shown in Figure 3 when N = 2, the sub-isolation circuit 3310 and the sub-isolation circuit 3320 are connected with the same load.

[0069] In some embodiments, when the isolation circuit includes N sub-isolation circuits, each of the N sub-isolation circuits can be connected to the same load when the frequency distance between the second signals filtered by the corresponding sub-isolation frequency ranges of each of the N sub-isolation circuits is relatively far. Figure 3 As shown in FIG. 31, when the frequency distance between the second signals filtered by the sub-isolation circuit 3310 and the sub-isolation circuit 3320 is relatively far, the sub-isolation circuit 3310 and the sub-isolation circuit 3320 can be connected to different loads, respectively.

[0070] In some embodiments, when the isolation circuit includes N sub-isolation circuits, the frequency distance between the second signals filtered by the corresponding sub-isolation frequency ranges of some of the N sub-isolation circuits is relatively far, and the frequency distance between the second signals filtered by the corresponding sub-isolation frequency ranges of some of the N sub-isolation circuits is relatively far. In this case, the sub-isolation circuits with the relatively far frequency distance can be connected to different loads, respectively, and the sub-isolation circuits with the relatively close frequency distance can be connected to the same load. The frequency distance can be considered as the difference between different frequencies. For example, the distance between the frequency band 1710 MHz and the frequency band 1910 MHz is 200 MHz. The relatively far frequency distance can be understood as a large difference between two frequency bands, and the relatively close frequency distance can be understood as a small difference between two frequency bands.

[0071] In some examples, the communication system itself includes a load. The isolation circuit can be connected to the load of the communication system, which can save the use of the load device, reduce the occupied area of the device, and reduce the cost of the communication module.

[0072] In some embodiments, when the filter circuit 120 and the isolation circuit 130 are both surface acoustic wave circuits, the IDT used in the isolation circuit 130 and the IDT used in the filter circuit 120 are of the same first type. The first type can include the substrate of the IDT and the metal strip of the IDT.

[0073] For example, the substrate used by the IDT is one of the important factors affecting the frequency of the IDT. The substrate used by the IDT in the isolation circuit 130 and the substrate used by the IDT in the filter circuit 120 are the same. For example, the substrate can be silicon, silicon carbide, etc.

[0074] For example, the metal strip of the interdigital electrode of the IDT is also one of the important factors affecting the frequency of the IDT. The IDT in the isolation circuit 130 and the IDT in the filter circuit 120 can use the same metal material for the metal strip.

[0075] When the first type of IDT used by the isolation circuit 130 and the filter circuit 120 is the same, the performance consistency of the filter device 100 can be ensured, which is conducive to better quality control in mass production. At the same time, when the first type of IDT used by the isolation circuit 130 and the filter circuit 120 is the same, the isolation circuit 130 and the filter circuit 120 can be placed in the same chip, which is conducive to the performance stability of the filter device 100.

[0076] Since the bandwidth of the circuit formed by the same type of IDT is limited, when the frequency bandwidth of the first signal is large, a plurality of sub-filter circuits can be arranged to cover the frequency range of the first signal. When the frequency bandwidth of the second signal is large, a plurality of sub-isolation circuits can be arranged to cover the frequency range of the second signal.

[0077] The filter device 100 in the embodiment of the present application can filter out the second signal different from the first signal from the received signal of the antenna received through the input end 110 through the isolation circuit 130, and absorb the second signal through the load. Based on this, the present application can filter out the second signal different from the first signal from the received signal of the antenna through the isolation circuit, and absorb the second signal through the load, thereby reducing the signal reflection of the second signal to the front-end circuit and reducing the signal interference problem of the second signal to the first signal, and further improving the overall performance of the communication system.

[0078] The embodiments of the present application will be described in detail below. Figure 3

[0079] Figure 3 As shown in FIG. 3, the filter device 300 can include an input end 310, a sub-filter circuit 3210, a sub-filter circuit 3220, a sub-isolation circuit 3310, a sub-isolation circuit 3320, and an output end 340.

[0080] As shown in FIG. 3, the filter device 300 can include an input end 310, a sub-filter circuit 3210, a sub-filter circuit 3220, a sub-isolation circuit 3310, a sub-isolation circuit 3320, and an output end 340. Figure 3 As shown in FIG. 3, the first sub-filter frequency range of the first signal that needs to be filtered in the sub-filter circuit 3210 can be set to 1710-1780MHz. The second sub-filter frequency range of the first signal that needs to be filtered in the sub-filter circuit 3220 can be set to 1850-1910MHz. The first sub-isolation frequency range of the second signal that needs to be filtered in the sub-isolation circuit 3310 can be set to 1930-2020MHz, and the second sub-isolation frequency range of the second signal that needs to be filtered in the sub-isolation circuit 3320 can be set to 2110-2210MHz.

[0081] The sub-filter circuit 3210 and the sub-filter circuit 3220 are electrically connected to the output end 340.

[0082] ​Both sub-isolation circuits 3310 and 3320 are electrically connected to the load.

[0083] Input terminal 310 is electrically connected to the antenna and is used to receive the received signal from the antenna.

[0084] Input terminal 310 inputs the received signal from the antenna to sub-filter circuit 3210, sub-filter circuit 3220, sub-isolation circuit 3310 and sub-isolation circuit 3320.

[0085] The sub-filter circuit 3210 can filter out the first signal in the frequency range of 1710-1780MHz.

[0086] The sub-filter circuit 3220 can filter out the first signal in the frequency range of 1850-1910MHz.

[0087] The sub-isolation circuit 3310 can filter out a second signal in the frequency range of 1930-2020MHz.

[0088] The sub-isolation circuit 3320 can filter out a second signal in the frequency range of 2110-2210MHz.

[0089] Figure 5 yes Figure 3 The test results of the filter device shown. Figure 5 As can be seen from the data, m23-m24 and m25-m27 are the first signals obtained through filtering. m27-m28 and m29-m30 are the second signals obtained through filtering.

[0090] Figure 6 yes Figure 3 The actual circuit layout corresponding to the filter device shown is as follows.

[0091] from Figure 6 The result can be obtained from the 1710-1780MHz passband, which includes A1, A2, A3, A4, A5, A6, A7, A8, A9, and A10, and the first signal within this frequency range is transmitted to the output.

[0092] from Figure 6 The result can be obtained from the 1850-1910MHz passband, which includes A11, A12, A13, A14, A15, A16, A17, A18, A19, and A20, and the first signal within this frequency range is transmitted to the output.

[0093] from Figure 6 The result shows that the passband of 2110-2210MHz, which can include A20, A21, A22, A23, and A24, can be obtained. After the second signal in this frequency range is transmitted to the load, the load can absorb the second signal.

[0094] From Figure 6 1930-2020MHz passband can be obtained, which can include A25, A26, A27, A28, A29, and after transmitting the second signal in this frequency range to the load, the load can absorb the second signal.

[0095] From Figure 6 As can be seen from

[0096] In some embodiments, the size of the conventional surface-mounted isolator is 10.3mm x 7.5mm x 2.5mm, and the substrate of other label isolators is also at the mm level. If the filter device shown in Figure 3 is used to replace the original filter device and surface-mounted isolator in the communication system, it can be obtained that the size of the filter device of the application increases by 1.6mm*0.7mm*0.9mm compared with the original filter device, which is much smaller than the size of the conventional surface-mounted isolator, so the filter device of the application can realize the isolation function of the fixed frequency band signal using a smaller area.

[0097] In some embodiments, the filter device in the embodiments of the application can be used to replace the conventional isolator used in the communication system to realize the electrical isolation between the upper and lower circuits on the microwave link. The filter device in the embodiments of the application can isolate the specific frequency, that is, the second signal while ensuring the communication of the first signal between the two ports, thereby improving the anti-interference ability between different frequency channels and reducing the occupied area of the radio frequency device, thereby reducing the cost of the communication system.

[0098] In the application, by setting an isolation circuit in the filter device, the second signal can be effectively filtered out and absorbed by the load, reducing the interference of the second signal on the first signal and the reflection phenomenon of the second signal, playing a role in isolating the first signal from the second signal and improving the anti-interference ability between different frequency channels. At the same time, the filter device of the application can replace the conventional isolator to electrically isolate the circuit of the communication system, reduce the occupied area of the radio frequency device, and thus improve the overall performance of the communication system.

[0099] The increase in the number of communication frequency bands has brought challenges to the anti-interference capabilities of communication technologies. To improve the anti-interference capabilities of different frequency band channels, multiple indicators need to be considered comprehensively. For example, passive intermodulation signals are a very important indicator of the anti-interference capability of frequency band communication. Passive intermodulation signals can refer to stray signals generated by two or more frequency signals in passive devices due to the nonlinear characteristics of the devices. If passive intermodulation signals are not suppressed or processed in a timely manner, they can cause serious damage to the communication system. For example, passive intermodulation signals can degrade the quality of communication signals and increase channel interference in the communication system.

[0100] When a filter device filters a received signal, the passive components can also generate intermodulation signals during the filtering process, causing interference to the filtered signal.

[0101] Taking the aforementioned filtering circuit and isolation circuit as examples, both the filtering circuit and isolation circuit can be surface acoustic wave (SAW) circuits, and both can include multiple individual time-varying depth (IDTs). The area of ​​the IDT closest to the antenna end can be larger than the areas of the other IDTs. For example, in the filtering circuit, the area of ​​the IDT closest to the antenna end can be larger than the areas of the other IDTs. For example, in the isolation circuit, the area of ​​the IDT closest to the antenna end can be larger than the areas of the other IDTs. For example, in both the isolation circuit and the filtering circuit, the area of ​​the IDT closest to the antenna end can be larger than the areas of the other IDTs.

[0102] by Figure 2 Taking the filter device shown as an example, the filter circuit 120 includes IDT 1201 to IDT 1209, and the isolation circuit 130 includes IDT 1301 to IDT 1305. Optionally, the area of ​​IDT 1201 can be larger than that of IDT 1202 to IDT 1209; optionally, the area of ​​IDT 1301 is larger than that of IDT 1301 to IDT 1305; optionally, the area of ​​IDT 1201 can be larger than that of IDT 1202 to IDT 1209, and the area of ​​IDT 1301 is larger than that of IDT 1301 to IDT 1305. IDT 1201 can have the same area as IDT 1301, or, when the area of ​​IDT 1201 is smaller than that of IDT 1301, the area of ​​IDT 1201 is larger than that of IDT 1301 to IDT 1305, or, when IDT 1201 is smaller than that of IDT 1301, the area of ​​IDT 1201 is larger than that of IDT 1301 to IDT 1305. When the area of ​​IDT1201 is larger than the area of ​​IDT1301, the area of ​​IDT1301 is larger than that of IDT1202 to IDT1209.

[0103] In some embodiments, the IDT closest to the antenna end can be a first IDT, and the other IDT can be a second IDT. Optionally, the first IDT can include a plurality of sub-IDTs connected in series, and the first IDT can have the same number of reflective gratings as the second IDT.

[0104] In some embodiments, the first IDT can have a larger area than the second IDT. Optionally, the sub-IDT can have a larger number of fingers than the second IDT, and / or the sub-IDT can have a larger aperture length than the second IDT. For example, when the sub-IDT has a larger number of fingers than the second IDT and a larger aperture length than the second IDT, the first IDT can be considered to have a larger area than the second IDT. Alternatively, when the sub-IDT has a larger number of fingers than the second IDT and a larger aperture length than the second IDT, the first IDT can also be considered to have a larger area than the second IDT.

[0105] In some embodiments, the filter circuit and the isolation circuit each include a plurality of IDTs, and the IDT closest to the antenna end can be a second IDT.

[0106] In some embodiments, the first IDT can be equivalent to the second IDT. For example, the first IDT can be equivalent to the second IDT in terms of capacitance. For example, the first IDT can include two IDTs connected in series, and the equivalent capacitance of the first IDT can be the same as the capacitance of the second IDT. For example, the first IDT can include two IDTs with a capacitance of 2PF, and the equivalent capacitance of the first IDT can be 1PF, which can be the capacitance of the second IDT.

[0107] Optionally, when the first IDT is equivalent to the second IDT in terms of capacitance, the first IDT can be used to replace the second IDT, and the first IDT can have a larger area than the second IDT.

[0108] For example, the first IDT can have a larger number of fingers than the second IDT, and / or the first IDT can have a larger aperture length than the second IDT. For example, when the first IDT has a larger number of fingers than the second IDT and a larger aperture length than the second IDT, the first IDT can be considered to have a larger area than the second IDT. Alternatively, when the first IDT has a larger number of fingers than the second IDT and a larger aperture length than the second IDT, the first IDT can also be considered to have a larger area than the second IDT.

[0109] Optionally, the first IDT can include a plurality of serially connected sub-IDTs, and the first IDT can have the same number of reflective gratings as the second IDT. When the first IDT and the second IDT have the same number of reflective gratings, the first IDT and the second IDT can be considered to have the same reflective unit, so as to ensure consistency of the surface acoustic wave in the process of propagation and reflection, thereby improving performance and reliability of the surface acoustic wave filter device.

[0110] In some embodiments, the plurality of serially connected sub-IDTs includes a first sub-IDT.

[0111] In some embodiments, an aperture area of the second IDT multiplied by a number of interdigital fingers of the second IDT multiplied by a first number can be equal to an aperture area of the first sub-IDT, and a finger width of the second IDT and a distance between adjacent fingers of the second IDT multiplied by a finger length of the second IDT can be equal to the aperture area of the second IDT, wherein the first number is related to a number of sub-IDTs included in the first IDT.

[0112] For example, the filter device 100 can include a first IDT 1101 and a second IDT 1201. Figure 2 Figure 2 The filter device 100 can include a filter circuit 120 and an isolation circuit 130, and the filter circuit 120 can include a plurality of second IDTs, and the isolation circuit 130 can include a plurality of second IDTs.

[0113] In some embodiments, the second IDT closest to the antenna end in the filter device can be replaced by the first IDT to generate a new filter device 1010. For example, the IDT 1201 can be replaced by the first IDT, or the IDT 1301 can be replaced by the first IDT, or the IDT 1201 and the IDT 1301 can be replaced by the first IDT.

[0114] ​For example, the first IDT can have a larger area than the second IDT, and the first IDT can be equivalent to the second IDT in terms of capacitance. The first IDT can include a plurality of sub-IDTs connected in series, and the first IDT can have the same number of reflector fingers as the second IDT. When the antenna end receives a plurality of signals, if the first IDT includes two first sub-IDTs, the node voltages of the two first sub-IDTs are each 1 / 2 of the node voltage of the second IDT. Although the first IDT and the second IDT have the same power intensity, it can also be understood that the sum of the power intensities of the two sub-IDTs is the same as the power intensity of the second IDT. Assuming that the power intensity of the second IDT is P, the power intensity of the sub-IDT can be P / 2. At this time, assuming that the third-order intermodulation signal power generated by the second IDT is Q, since the third-order intermodulation signal is proportional to the cube of the power generated by the passive device, the third-order intermodulation signal generated by the first sub-IDT is 1 / 8 of the third-order intermodulation signal power generated by the second IDT, so the third-order intermodulation signal generated by the two first sub-IDTs is Q / 4, and the intermodulation signal generated by the first IDT is less than the intermodulation signal generated by the second IDT.

[0115] For example, when the first IDT has a larger area than the second IDT, the number of interdigital fingers of the sub-IDT can be greater than or equal to that of the second IDT, and / or the aperture length of the sub-IDT can be greater than or equal to that of the second IDT.

[0116] In some embodiments, when the filter device 100 described above and the new filter 1010 are used to filter the same signal, since the first IDT is equivalent to the second IDT, the node voltage of each sub-IDT in the first IDT is reduced relative to the node voltage of the second IDT, and thus the passive intermodulation signal generated by each sub-IDT is also reduced. Since the reduction of the passive intermodulation signal is nonlinear, the total intermodulation signal generated by the first IDT in the filter 1010 is lower than the intermodulation signal generated by the second IDT in the filter 100. It can be understood that when the filter 1010 is generated by replacing the second IDT closest to the antenna end in the filter 100 with the first IDT, the intermodulation signal generated by the filter 1010 is lower than the intermodulation signal generated by the filter 100 under the premise that the input signal is unchanged, thereby improving the overall performance of the communication system.

[0117] Since the received signal of the antenna depends on the functional requirements of the communication system, the antenna can receive a signal with a large power. In order to ensure the performance of the entire communication system, the filtering circuit and the isolation circuit in the filtering device proposed in the embodiments of the present application can select a filtering circuit and an isolation circuit suitable for receiving a large power signal. For example, the filtering circuit and the isolation circuit can be a T-type filtering circuit. The T-type filtering circuit can match the impedance on both sides by correctly selecting the element value, so as to maximize the power transmission between the active stage, the switch and the antenna. This impedance matching capability is crucial for the reception and processing of a large power signal, because it can reduce signal loss and improve the transmission efficiency of the signal.

[0118] In some embodiments, when the antenna receives a signal with a small power, the filtering circuit and the isolation circuit in the filtering device proposed in the embodiments of the present application can select a filtering circuit and an isolation circuit suitable for receiving a small power signal. For example, the filtering circuit and the isolation circuit can be a DMS filter. The DMS filter can be coupled in the longitudinal direction by two identical resonance modes, so as to achieve a lower insertion loss and a good out-of-band rejection characteristic. Therefore, the signal loss is small when the signal passes through the DMS filter, which helps to receive a signal with a small power.

[0119] The filtering device in the embodiments of the present application can filter out the second signal different from the first signal frequency in the received signal of the antenna received through the input end through the isolation circuit, and absorb the second signal through the load. Based on this, the present application can filter out the second signal different from the first signal in the received signal of the antenna through the isolation circuit, and absorb the second signal through the load, thereby reducing the signal reflection of the second signal to the front-end circuit and reducing the signal interference problem of the second signal to the first signal, and further improving the overall performance of the communication system.

[0120] To achieve the above object, the utility model also proposes a kind of communication equipment, and communication equipment includes the filtering device as described above. Since the communication equipment of the present application adopts all the technical solutions of the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here.

[0121] The above is only the preferred embodiment of the utility model, and does not limit the patent range of the utility model, and any equivalent structure or equivalent process transformation using the contents of the utility model specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection range of the utility model.

[0122] It should be understood that the terms "system" and "network" can be used interchangeably in this application. In addition, the terms used in this application are only used to explain the specific embodiments of the application, and are not intended to limit the application. The terms "first", "second", "third", and "fourth" and the like in the specification and claims of the application and the drawings are used to distinguish different objects, and are not used to describe a specific order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion.

[0123] In embodiments of the present application, a "field" can also be referred to as a "domain", a "subfield" or a "sub-field". A field can occupy one or more bytes (octets), or a field can occupy one or more bits.

[0124] In embodiments of the present application, the term "indicates" can be direct indication or indirect indication, or can represent an associated relationship. For example, A indicates B, which can mean that B can be obtained directly through A; or it can mean that A indirectly indicates B, for example, A indicates C, and B can be obtained through C; or it can mean that A and B have an associated relationship.

[0125] In embodiments of the present application, "B corresponding to A" means that B is associated with A, and B can be determined according to A. However, it should also be understood that determining B according to A does not mean that B is determined only according to A, but B can also be determined according to A and / or other information.

[0126] In embodiments of the present application, the term "corresponding" can mean a direct or indirect corresponding relationship between the two, or can mean an associated relationship between the two, or can mean an indication and being indicated, configuration and being configured, etc.

[0127] In embodiments of the present application, "predefined" or "preconfigured" can be implemented by pre-saving corresponding codes, tables or other means for indicating related information in the device, and the specific implementation manner is not limited in the present application. For example, predefinition can mean definition in a protocol.

[0128] In embodiments of the present application, the term "and / or" is only a description of the associated relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in this paper generally represents an "or" relationship between the associated objects before and after it.

[0129] In the embodiments of the present application, the "comprising" can mean directly comprising or indirectly comprising. Alternatively, the "comprising" mentioned in the embodiments of the present application can be replaced by "indicating" or "used for determining". For example, A comprising B can be replaced by A indicating B, or A used for determining B.

[0130] In various embodiments of the present application, the size of the serial number of the above processes does not mean the order of execution, the execution order of the processes should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0131] In the embodiments of the present application, the "protocol" can refer to a standard protocol in the communication field, for example, it can include WiFi protocol and related protocols applied to future WiFi communication systems, which is not limited in the present application.

[0132] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented by other ways. For example, the device embodiments described above are only schematic, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms.

[0133] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. According to actual needs, part or all of the units can be selected to achieve the purpose of the embodiments of the present application.

[0134] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit.

[0135] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center through wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) mode. The computer readable storage medium can be any available medium that can be read by a computer or a data storage device such as a server, data center and the like integrated with one or more available media sets. The available media can be magnetic media (for example, floppy disk, hard disk, magnetic tape), optical media (for example, digital video disc (DVD)) or semiconductor media (for example, solid state disk (SSD)) and the like.

[0136] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A filtering device, characterized in that, The filtering device includes: an input terminal, an output terminal, a filtering circuit, and an isolation circuit. The input terminal is electrically connected to the antenna, and the input terminal is used to receive the received signal from the antenna. The input terminal receives the signal from the antenna and inputs it into the filtering circuit and the isolation circuit. The filtering circuit is electrically connected to the output terminal, and the filtering circuit is used to filter the received signal from the antenna to obtain a first signal. The isolation circuit is electrically connected to the load, and is used to filter the received signal from the antenna to obtain a second signal. The first signal is the frequency signal that the filtering device needs to output. The second signal is a frequency signal in the received signal of the antenna that has a different frequency than the first signal.

2. The filtering device according to claim 1, characterized in that, The isolation circuit is a surface acoustic wave (SAW) isolation circuit, which includes multiple independent time-discharge (IDTs). The isolation circuit includes N sub-isolation circuits, which are connected in parallel. The sub-isolation circuit is used to filter out the second signal that belongs to the sub-isolation frequency range. The sub-isolation circuit and the sub-isolation frequency range are in one-to-one correspondence, and N is a positive integer.

3. The filtering device according to claim 2, characterized in that, Each of the N sub-isolation circuits is connected to the same load, or The N sub-isolation circuits are connected to N loads, or Some of the N sub-isolation circuits are connected to the same load.

4. The filtering device according to claim 2, characterized in that, The filtering circuit is a surface acoustic wave (SAW) filtering circuit, which includes multiple independent current transformers (IDTs). The isolation circuit includes multiple IDTs of the same first type as the filtering circuit, which also includes multiple IDTs. The first type includes one or more of the following: the substrate of the IDT, and the metal strip of the IDT.

5. The filtering device according to claim 2, characterized in that, The filtering circuit includes M sub-filter circuits, which are connected in parallel. The sub-filter circuit is used to filter out the first signal that belongs to the sub-filter frequency range. The sub-filter circuit and the sub-filter frequency range are in one-to-one correspondence, and M is a positive integer.

6. The filtering device according to claim 1, characterized in that, The filtering circuit and / or the isolation circuit each include multiple IDTs, and in the filtering circuit and / or the isolation circuit, the area of ​​the IDT closest to the antenna end is larger than the area of ​​the other IDTs.

7. The filtering device according to claim 6, characterized in that, The IDT closest to the antenna end is the first IDT, and the other IDTs are the second IDTs. The first IDT includes multiple sub-IDTs connected in series. The number of reflective gratings in the first IDT is the same as the number of reflective gratings in the second IDT. The cross factor of the sub-IDT is greater than or equal to that of the second IDT, and / or the aperture length of the sub-IDT is greater than or equal to that of the second IDT.

8. The filtering device according to claim 7, characterized in that, The plurality of cascaded sub-IDTs include a first sub-IDT. The area of ​​the aperture region of the second IDT multiplied by the cross factor of the second IDT, and then multiplied by the first number, equals the area of ​​the aperture region of the first sub-IDT. The sum of the interdigit width of the second IDT and the distance between adjacent interdigits of the second IDT, multiplied by the interdigit length of the second IDT, equals the area of ​​the aperture region of the second IDT. The first number is related to the number of sub-IDTs included in the first IDT.

9. The filtering device according to claim 1, wherein the filtering device is placed in a communication system, characterized in that, The load includes the load of the communication system.

10. The filtering device according to claim 1, characterized in that, Based on the signal power of the received signal from the antenna, the filtering circuit and the isolation circuit employ a T-type filtering circuit and / or a dual-mode surface acoustic wave filter circuit.

11. A communication device, characterized in that, Includes the filtering device as described in any one of claims 1 to 9.

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