Tunable filter with mutually coupled inductor

Abstract

To provide a tunable filter with tunable rejection, a method of filtering, a radio frequency system, a radio frequency module, and a wireless communication device.SOLUTION: A tunable filter 40 for filtering radio frequency signals includes a plurality of mutually coupled inductors L1, L2 and a tunable impedance circuit 42 electrically connected to at least one of the mutually coupled inductors. The tunable impedance circuit adjusts at least two notches in the frequency response of the tunable filter by changing the states of switches S11, S12, ...S1N.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] Cross-reference to priority application Any foreign or domestic priority claim identified in the Application Data Sheet filed with this application Any and all applications filed under this section are hereby incorporated by reference pursuant to 37 CFR Section 1.57. This application is incorporated herein by reference as a "tunable filter with mutually coupled inductors." U.S. Provisional Application No. 63 / 046,184, filed June 30, 2020, entitled " and August 2020, entitled "Tunable Filter with Mutually Coupled Inductors" This application claims the benefit of priority to U.S. Provisional Application No. 63 / 071,261, filed on January 27, 2014. The disclosures of each of these are incorporated herein by reference in their entirety.

[0002] Embodiments of the present disclosure are arranged to filter signals such as radio frequency signals. This relates to filters. [Background technology]

[0003] A radio frequency (RF) communication system for transmitting and / or receiving signals over a wide range of frequencies. For example, an RF communication system may use Approximately 410 megahertz (MHz) to approximately 7.12 MHz for fifth-generation (5G) cellular communications In the frequency range of about 30 kHz to about 300 GHz, such as the 5 gigahertz (GHz) range Certain RF signals can be used to communicate wirelessly.

[0004] RF communication systems include mobile phones, tablets, base stations, and network access points. This includes, without limitation, laptops, customer premises equipment (CPE), laptops, and wearable electronic devices. obtain.

[0005] In a given application, an RF communication system may process multiple RF signals simultaneously. In such RF communication systems, filters with strong harmonic rejection are required. Desirable. Filters with strong harmonic rejection are desirable in a variety of applications. Summary of the Invention

[0006] Each of the claimed innovations has several aspects, each of which is Not only one of the elements is responsible for the desired attribute. Without limiting the scope, a brief summary of some prominent features of the disclosure will now be described.

[0007] One aspect of the present disclosure is a tunable filter in which the rejection is tunable. The filter includes a first inductor and a second inductor mutually coupled to the first inductor. a tunable impedance circuit electrically connected to the first inductor; The tunable impedance circuit includes a switch, and the state of the switch is at least two variations in the frequency response of the tunable filter by varying The tunable filter is configured to adjust the notch. The data are arranged for filtering.

[0008] The switch is arranged to selectively electrically couple one end of the capacitor to the first inductor. The tunable impedance circuit can be connected to one end of the second capacitor. may include a second switch arranged to selectively electrically couple to the first inductor .

[0009] For a given application, frequency response can be adjusted by changing the switch state. The position of at least three notches in the answer can be adjusted.

[0010] The location of the notch in the frequency response of the tunable filter is at least the state of the variable impedance circuit and the mutual coupling between the first inductor and the second inductor; may be based on

[0011] The tunable impedance circuit includes a tunable capacitance circuit. The tunable capacitance circuit may be a first inductor and a second inductor. Alternatively, a shunt capacitance can be applied to the node between the The tunable capacitance circuit may be in parallel with the first inductor. The impedance circuit may also be in series with the second inductor. It may include a second tunable capacitance circuit in parallel with the second inductor.

[0012] The first inductor may be in series with the second inductor, and the first capacitance may be A second capacitance may be in parallel with the second inductor, and a second capacitance may be in parallel with the second inductor. The filter further includes a shunt coupled between the first inductor and the second inductor. The tunable impedance circuit may include a first capacitance It may be configured to provide:

[0013] The first inductor may be a series inductor and the second inductor may be a shunt inductor. The tunable impedance circuit may include a tuning The tunable filter may further include a first impedance circuit. The inductor-capacitor circuit may include an inductor-capacitor circuit in series with the inductor. may include a third inductor, and the third inductor may be a may be interconnected with at least one of

[0014] At least two notches may provide harmonic rejection.

[0015] Another aspect of the present disclosure is a method of filtering a radio frequency signal. The method includes: filtering the first radio frequency signal with a tunable filter in a and after filtering the first radio frequency signal, tuning of the tunable filter. The state of the switch of the adjustable impedance circuit is changed from a first state to a second state. The frequency response of the tunable filter has at least two notches corresponding to harmonics. and adjusting the position of the tunable filter, wherein the tunable filter includes a mutually coupled inductor and a A tunable impedance circuit is included, is electrically connected to the mutually coupled inductor; and the tunable filter a second radio frequency signal is filtered by the tunable filter while the filter is in the second state; This includes filtering.

[0016] In a given application, the tuning At least three notches in the frequency response of the adjustable filter can be adjusted.

[0017] Another aspect of the present disclosure is a tunable filter and a method for controlling the tunable filter. and an antenna configured to transmit a filtered radio frequency signal. The tunable filter is a communication device having a first inductor and a second inductor. a second inductor mutually coupled to the first inductor; and a tuning and a tunable impedance circuit. The tunable impedance circuit includes a switch. and the frequency domain of the tunable filter can be adjusted by changing the state of the switch. The at least two notches in the shaft are configured to adjust.

[0018] The wireless communication device includes an antenna switch and connects a tunable filter to the antenna. The antenna may be coupled between the switch and the antenna.

[0019] The wireless communication device may include a power amplifier and a band select switch, and may be tunable. A filter may be coupled between the power amplifier and the band select switch.

[0020] Another aspect of the present disclosure is a tunable filter for rejecting harmonics. The filter includes a first inductor and a second inductor mutually coupled to the first inductor. and a tunable capacitance circuit electrically connected to the first inductor. The tunable capacitance circuit must be at least 2x2 N Tuning for Harmonics A tunable capacitance is provided to tune the harmonic rejection of the filter. N switches configured to adjust the effective capacitance of the circuit, where: N is a positive integer greater than 1. The tunable filter filters the radio frequency signal. The data are arranged for filtering.

[0021] N switches are at least 3x2 N High-performance tunable filters for harmonics It can be configured to be tunable to tune the harmonic rejection.

[0022] The tunable capacitance circuit may be in parallel with the first inductor. The filter further comprises a capacitance in parallel with the second inductor and a capacitance in parallel with the first inductor. and a shunt capacitance between the first inductor and the second inductor, It is in series with the inductor.

[0023] Tuning is possible by changing the state of the first switch among multiple switches. At least two notches in the frequency response of the filter can be varied in position. By changing the state of the first of the switches, the tunable filter The position of at least three notches in the filter's frequency response can be varied.

[0024] The second inductor may be a shunt inductor. The tunable filter may further include a second inductor The second inductor may include a shunt capacitor in series with the second inductor. is electrically connected to the first inductor via the

[0025] 3×2 N The harmonics include at least one second harmonic and at least one third harmonic. May contain 2×2 N Harmonics are at least some of the components associated with the 5th generation New Radio operating bands. Each may contain one harmonic. N Harmonics are related to the 5th generation new radio operating band. At least one harmonic coupled and 4th Generation Long Term Evolution operating band and at least one harmonic associated with the frequency range.

[0026] Another aspect of the present disclosure is a radio frequency front end including a tunable filter; and an antenna in communication with the radio frequency front end. The tunable filter includes a first inductor and a second inductor mutually coupled to the first inductor. a tunable capacitance circuit electrically connected to the first inductor. The tunable capacitance circuit includes at least 2×2 N for harmonics To tune the harmonic rejection of the tunable filter, a tunable capacitor is used. N switches configured to adjust the effective capacitance of the resistivity circuit where N is a positive integer greater than 1. The tunable filter is The filter is arranged to filter the signal.

[0027] The antenna receives radio frequency signals filtered by a tunable filter. N may be at least 4.

[0028] The radio frequency front end includes an antenna switch and applies a tunable filter. The antenna switch may be coupled between the antenna and the antenna.

[0029] The radio frequency front end may include a power amplifier and a band select switch. A band selectable filter may be coupled between the power amplifier and the band select switch.

[0030] The wireless communication device may be configured to implement dual connectivity and may include a tunable filter. The wireless communication device may be configured to provide blocking for such dual connectivity. The tunable filter may be configured to implement carrier aggregation. , configured to provide blocking for carrier aggregation.

[0031] Another aspect of the present disclosure is an antenna switch, an antenna port, and a method for connecting the antenna switch and a a radio including a tunable filter coupled to a signal path between the antenna port and the radio; The tunable filter is a frequency system. a second inductor mutually coupled to the first inductor; and a tuning inductor electrically connected to the first inductor. and a tunable capacitance circuit. The tunable capacitance circuit comprises at least Also 2×2 N To tune the harmonic rejection of a tunable filter for harmonics. and configured to adjust the effective capacitance of the tunable capacitance circuit. It contains N switches, where N is a positive integer greater than 1. Tuning The variable filter is arranged to filter the radio frequency signal.

[0032] For purposes of summarizing this disclosure, certain aspects, advantages and novel features of the innovation are set forth herein. It should be understood that not all such advantages are necessarily present in any one of the present inventions. Therefore, the present invention is not limited to the specific embodiments described herein. Any one advantage or group of advantages taught herein does not necessarily imply any other advantage taught or suggested herein. It may be embodied or performed in a manner that achieves or optimizes, without achieving. [Brief explanation of the drawings]

[0033] Embodiments of the present disclosure will now be described by way of non-limiting example with reference to the accompanying drawings.

[0034] [Figure 1] FIG. 1 is a schematic diagram of an example of a communication network. [Figure 2A] FIG. 1 is a schematic diagram of an example of a communication link using carrier aggregation. [Figure 2B] 2B illustrates various examples of uplink carrier aggregation for the communication link of FIG. 2A. [Figure 2C] 2B illustrates various examples of downlink carrier aggregation for the communication link of FIG. 2A. [Figure 3] FIG. 1 is a diagram of an example of a dual-connection network topology. [Figure 4] FIG. 1 is a schematic diagram of a tunable filter according to an embodiment. [Figure 5] FIG. 10 is a schematic diagram of a tunable filter according to another embodiment. [Figure 6] FIG. 10 is a schematic diagram of a tunable filter according to another embodiment. [Figure 7] FIG. 10 is a schematic diagram of a tunable filter according to another embodiment. [Figure 8A] FIG. 10 is a schematic diagram of a tunable filter according to another embodiment. [Figure 8B] FIG. 10 is a schematic diagram of a tunable filter according to another embodiment. [Figure 8C] 8C is a graph of the frequency response of the filter of FIG. 8B. [Figure 9] FIG. 1 is a schematic diagram of a tunable filter according to an embodiment. [Figure 10] 1 is a graph of coupling coefficient versus distance between two mutually coupled inductors. [Figure 11] 10 is a simulation graph showing the location of harmonic notches for the tunable filter of FIG. 9 according to the first design example. [Figure 12] 10 is a simulation graph showing the location of harmonic notches for the tunable filter of FIG. 9 according to a second design example. [Figure 13] FIG. 1 is a schematic diagram of a tunable filter according to an embodiment. [Figure 14] 14 is a simulation graph showing harmonic notch locations for the tunable filter of FIG. 13 according to a third design example. [Figure 15A] FIG. 1 is a schematic block diagram of a radio frequency system including a tunable filter according to an embodiment. [Figure 15B] FIG. 1 is a schematic block diagram of a radio frequency system including a tunable filter according to another embodiment. [Figure 16] FIG. 1 is a schematic diagram of an embodiment of a mobile device. DETAILED DESCRIPTION OF THE INVENTION

[0035] The following detailed description of certain embodiments represents various descriptions of specific embodiments. However, the innovations described herein are defined and covered, for example, by the claims. In this description, the same reference numerals refer to the same Reference is made to the drawings which may show identical or functionally similar elements. It is further understood that elements shown in the drawings are not necessarily to scale. The embodiments may include more elements than shown in the drawings and / or may include more elements than shown in the drawings. Additionally, some embodiments may include a subset of features from more than one drawing. Any suitable combination may be incorporated. The headings provided herein are for convenience only. These are merely illustrative and are not intended to necessarily affect the meaning or scope of the claims. .

[0036] The International Telecommunication Union (ITU) is the governing body for information and communications technologies, including the use of the international radio spectrum. It is a specialized agency of the United Nations (UN) responsible for global issues related to the

[0037] The 3rd Generation Partnership Project (3GPP) is a joint venture between the Association of Radio Industries and Businesses (ARIB), Telecommunications Technology Committee (TTC), China Communications Standards Association (CCSA), US Telecommunications Industry Standards Association The Telecommunications Technology Association (ATIS), the Telecommunications Technology Association (TTA), and the European Telecommunications Standards Institute ( Telecommunication standards around the world, such as ETSI, and Telecommunication Standards Institute of India (TSDSI) It is a collaborative effort between a group of organizations.

[0038] Working within the ITU, 3GPP is responsible for, for example, second generation (2G) technologies. (e.g., Global System for Mobile Communications (GSM) ) and Enhanced Data Rates for GSM Evolution (EDGE), Third generation (3G) technologies (e.g., Universal Mobile Telecommunications System (UMTS) and high-speed High-Speed ​​Internet Access (HSPA), and fourth-generation (4G) technologies (e.g., Long-Term Evolution Technical expertise on various mobile communication technologies, including LTE (Long-Term Evolution) and LTE Advanced Develop and maintain technical specifications.

[0039] Technical specifications maintained by 3GPP may be extended and revised through specification releases. Specification releases can span multiple years and specify a wide range of new features and evolutions.

[0040] In one example, 3GPP has announced carrier aggregation for LTE in Release 10. Initially, two downlink carriers were introduced, but 3GPP P supports up to five downlink carriers and up to three uplink carriers in Release 14. Carrier aggregation has been extended to include carriers. Other examples of new features and advancements include License Assistant Access (LAA), Extended LAA (eLAA), Narrowband Internet of Things (NB-IOT), Vehicle Two including but not limited to V2X (Vehicle to Everyday), and High Power User Equipment (HPUE) do not have.

[0041] 3GPP has completed the deployment of Phase 1 of fifth-generation (5G) technology in Release 15, Currently, Phase 2 of 5G technology is being introduced in Release 16. The lease will further evolve and expand 5G technology. 5G technology will also be It is also called 5G New Radio (NR).

[0042] 5G NR will be able to operate over mmWave spectrum, with beamforming capabilities and high spectrum Efficient waveforms, low latency communications, multiple radio numerology, and / or non-orthogonal multiple access ( It supports or is planned to support various features such as NOMA. Although the RF capabilities provided by the network provide flexibility and increase user data rates, ,Supporting such features can pose a number of technical difficulties.

[0043] The teachings herein may be used with LTE Advanced, LTE Advanced Pro and / or 5G NR. This includes, but is not limited to, communication systems that use advanced cellular technologies such as It is applicable to a wide variety of communication systems.

[0044] harmonic rejection

[0045] Fifth Generation (5G) New Radio (NR) technology is expected to meet harmonic rejection specifications. The more integrated or integrated we are, the more bands of signals are generated simultaneously. Various applications will be able to meet various 5G NR harmonic specifications. Further tunability for the addition filter is desirable. Examples of this are carrier aggregation applications, dual connectivity applications, 5G Applications where NR FR1 signals and 5G NR FR2 signals coexist, and other Includes coexistence applications, etc.

[0046] Some solutions include a switch to tune the harmonic rejection. In such a solution, one switch is used to select two harmonic states, typically two According to this technique, N switches can be controlled to switch between two bands. N pieces Since there are many bands, it is possible to control the harmonic state up to A relatively large number of switches may be used to achieve this. It is costly to implement.

[0047] Aspects of the present disclosure include mutually coupled inductors and tunable impedance circuits The tunable impedance circuit relates to a filter. To adjust the capacitance provided by the impedance circuit, each The N switches may be interconnected to couple the capacitors. When used with an inductor, the filter can be N Achieving a harmonic state Here, N is a positive integer, M is a positive integer equal to or greater than 2, and M is the number of channels in each band. is the number of harmonics of interest for a given application. This may correspond to one more than the number of mutual couplings between inductor pairs in the functional filter.

[0048] The filters disclosed herein advantageously include a number of additional harmonic tuning options to increase harmonic tunability. The disclosed filter uses inductive mutual coupling. Reducing switch die area and / or cost for tunable harmonic states can be done.

[0049] The filters disclosed herein can filter any suitable harmonics. For example, the filters disclosed herein can filter out the following harmonics: second harmonic, third harmonic, It is possible to filter one or more of the 1st harmonic, 4th harmonic, 5th harmonic, 6th harmonic, etc. Such harmonics are simultaneously rejected by filters according to the principles and advantages disclosed herein. It is possible.

[0050] Although embodiments are described with reference to harmonic rejection, any suitable application of the filters disclosed herein may be used. The appropriate principles and advantages provide any suitable out-of-band rejection and / or notch filtering. can be used for

[0051] communication network

[0052] FIG. 1 is a schematic diagram of an example of a communication network 10. The communication network 10 includes: Macrocell base station 1, mobile device 2, small cell base station 3, and stationary wireless device 4 Includes:

[0053] The communication network 10 shown in FIG. 1 may be, for example, a 4G LTE, a 5G NR, or a Wi-Fi network. using a variety of technologies, including wireless local area networks (WLANs) such as Wi-Fi In the communication network 10, the dual connectivity includes a mobile device 2 It is possible to implement simultaneous 4G LTE and 5G NR communication. Although various examples of technologies are given, the communication network 10 may include a wide variety of It can be adapted to support communication technologies.

[0054] Various communication links of a communication network 10 are depicted in FIG. Frequency Division Duplexing (FDD) and / or Time Division Duplexing (TDD) FDD can be duplexed in a variety of ways, including by using different duplexing methods for signal transmission and signal reception. FDD is a type of radio frequency communication that uses different frequencies. TDD, in contrast, can provide a number of benefits, such as reduced latency. A time when the same frequency is used for signal transmission and reception, and transmission and reception are switched at regular intervals. TDD is a type of radio frequency communication that utilizes the spectrum efficiently and A number of advantages can be provided, such as variable distribution of throughput between directions.

[0055] As shown in FIG. 1, the mobile device 2 is a combination of 4G LTE technology and 5G NR technology. The mobile device communicates with the macrocell base station 1 via a communication link that uses a combination of 2 also communicates with small cell base station 3. In the illustrated example, mobile device 2 and small cell base station 3, which uses 5G NR technology, 4G LTE technology, and Wi-Fi technology. In certain implementations, the Extended License Assistance Licensed access (eLAA) is provided by one or more licensed frequency carriers (e.g., 4G LTE frequencies and / or 5G NR frequencies) in one or more licensed used to aggregate with unlicensed carriers (e.g. unlicensed Wi-Fi frequencies) It is used.

[0056] In certain implementations, the mobile device 2 uses 5G NR technology to communicate with the surrounding area. Through one or more frequency bands within and / or exceeding Frequency Range 1 (FR1) It communicates with macrocell base station 2 and small cell base station 3 via one or more frequency bands. One or more frequency bands within FR1 may be below 6 GHz. For example, wireless communication may be Frequency Range 1 (FR1), Frequency Range 2 (FR2), or a combination thereof can be used. In an embodiment, the mobile device 2 supports the HPUE power class specification.

[0057] The illustrated small cell base station 3 also communicates with stationary wireless devices 4. The base station 3 is, for example, a mobile station for providing broadband services using 5G NR technology. In a given implementation example, the small cell base station 3 can use via one or more millimeter wave frequency bands in the 300 GHz frequency range, and / or through the upper centimeter wave frequency band in the frequency range of 24 GHz to 30 GHz. , and communicates with a stationary wireless device 4.

[0058] In a given implementation, the small cell base station 3 uses beamforming to For example, beamforming can be used to communicate with wireless devices 4 over millimeter wave frequencies. Concentrate signal strength to overcome path losses such as the high losses associated with multiple communications It can be used to

[0059] The communication network 10 of FIG. 1 includes a macrocell base station 1 and a small cell base station 3. In a given implementation, the small cell base station 3 has a relative It can operate with low power, short range, and / or few simultaneous users. The cell base station 3 may also be referred to as a femtocell, picocell or microcell.

[0060] Although communication network 10 is shown as including two base stations, Network 10 may include more or fewer base stations and / or other types of base stations. As shown in Figure 1, these base stations provide wireless backhaul. Additionally or alternatively, the base stations may communicate with each other using wireless communication. may also communicate with each other using wired and / or optical links.

[0061] The communication network 10 of FIG. 1 includes one mobile device and one stationary wireless device. The mobile device 2 and the stationary wireless device 4 are user devices or Two examples of user equipment (UE) are shown. The communication network 10 includes two user devices. Although depicted as such, communication network 10 may have more or fewer users. can be used to communicate with user devices and / or other types of user devices. For example, user devices can be mobile phones, tablets, laptops, IoT devices, etc. The devices may include smartphones, wearable electronics, and / or a wide variety of other communication devices.

[0062] User devices of communication network 10 may access available network services in a variety of ways. They may share resources (eg, available frequency spectrum).

[0063] In one example, frequency division multiple access (FDMA) divides a frequency band into multiple frequency carriers. Additionally, one or more carriers may be assigned to a particular user. Examples of FDMA are Single Carrier FDMA (SC-FDMA) and Orthogonal FDMA. OFDMA includes, but is not limited to, OFDMA, which uses available bandwidth in multiple ways. Multi-carrier technology is a technique that subdivides the signal into a number of mutually orthogonal narrowband subcarriers, which is different Can be assigned separately to users.

[0064] Another example of shared access is when a user has access to a specific time slot using a frequency resource. Time Division Multiple Access (TDMA), which assigns a unique code to each user device Code division multiple access (CDMA) is a method in which frequency resources are shared among different users by allocating CDMA), beamforming is used to provide shared access through spatial division Spatial Division Multiple Access (SDMA) and power domains are used for multiple access purposes. These include, but are not limited to, non-orthogonal multiple access (NOMA), which uses: For multiple users at the same frequency, time and / or code but at different power levels It can be used accordingly.

[0065] Enhanced Mobile Broadband (eMBB) is an increasing system of LTE networks Refers to technology for capacity. For example, eMBB provides at least 10 Gbps of data rate to each user. It is possible to mention that the device must communicate at a minimum peak data rate of 100Mbps. Ultra-reliable low latency communication (uRLLC) provides extremely low latency, e.g., less than 2 milliseconds. URLLC is a technology that communicates with low latency. and / or for mission-critical communications purposes such as telesurgery applications. Massive Machine-Based Communications (mMTC) is a key technology for the Internet of Things (IoT). Wireless connectivity to everyday objects, such as those associated with applications It refers to the associated low cost and low data rate communication.

[0066] The communication network 10 of FIG. 1 includes eMBB, uRLLC, and / or mMTC. It can be used to support a wide variety of advanced communication functions, including but not limited to: Cut.

[0067] The peak data rate of a communication link (e.g., between a base station and a user device) may vary. For example, the peak data rate depends on the channel bandwidth, modulation order, and component The bandwidth is affected by the number of component carriers and / or the number of antennas used for communication.

[0068] For example, in a given implementation, the data rate of the communication link is M*B*log2(1 + S / N), where M is the number of communication channels and B is the number of channels where S / N is the signal-to-noise ratio (SNR).

[0069] Therefore, the data rate of a communication link increases with the number of antennas used (e.g., By increasing the number of communication channels (e.g., by aggregating carriers) and / or by improving SNR. (e.g., by increasing transmit power and / or improving receiver sensitivity) , may increase.

[0070] 5G NR communication systems will be equipped with a variety of technologies to improve data rates and / or communication performance. A variety of techniques can be used.

[0071] Carrier Aggregation

[0072] FIG. 2A is a schematic diagram of an example communication link using carrier aggregation. Carrier aggregation supports communication over multiple frequency carriers, and thus In some cases, fragmented spectrum allocations are utilized to increase user data rates and Use higher bandwidth for communication links by improving network capacity Carrier aggregation can present challenges for harmonic rejection. The filter shown provides harmonic rejection in carrier aggregation applications. The radio frequency front end architecture disclosed herein can be implemented to provide The architecture can be implemented in dual-connection applications.

[0073] In the illustrated example, a communication link is provided between a base station 21 and a mobile device 22. As shown in FIG. 2A, the communication link is an RF communication link from a base station 21 to a mobile device 22. downlink channel used for RF communication from mobile device 22 to base station 21 and an uplink channel used for

[0074] Although FIG. 2A illustrates carrier aggregation in the context of FDD communications, Carrier aggregation can also be used for TDD communications.

[0075] In certain implementations, the communication link may include a downlink channel and an uplink channel. For example, a communication link may provide asymmetric data rates for mobile devices. Relatively high bandwidth to enable high-speed streaming of multimedia content to devices Supports downlink data rates while providing data access from mobile devices to the cloud It can be used to provide a relatively slow data rate for uploading.

[0076] In the illustrated example, the base station 21 and the mobile device 22 select the bandwidth of the communication link. communicate via carrier aggregation that can be used to selectively increase Carrier aggregation is a method in which adjacent carriers within the same operating frequency band are aggregated. Carrier aggregation may also be discontinuous and may involve aggregation within a common band. Or frequencies in different bands may include separated carriers.

[0077] In the example shown in Figure 2A, the uplink channel is divided into three aggregated components: Carrier f UL1 , f UL2 and f UL3 Additionally, a downlink channel is the sum of the five aggregated component carriers f DL1 , f DL2 , f DL3 , f DL4 and f DL5 Although an example of component carrier aggregation is shown, However, more or less for uplink and / or downlink purposes may be used. Carriers may be aggregated. Furthermore, the number of aggregated carriers depends on the desired uplink and The bandwidth can be varied over time to achieve the desired downlink and downlink data rates.

[0078] For example, for uplink and / or downlink communications with a particular mobile device The number of carriers aggregated in may change over time. For example, the number of carriers aggregated in , as the device moves through the communication network, and / or may change as usage changes over time.

[0079] FIG. 2B illustrates various uplink carrier aggregation schemes for the communication link of FIG. 2A. Figure 2B shows a first example that illustrates three types of carrier aggregation. Carrier aggregation scenario 31, second carrier aggregation scenario 32, and and third carrier aggregation scenarios33.

[0080] Carrier aggregation scenarios 31 to 33 are based on the first component carrier f UL 1, a second component carrier f UL2 , and the third component carrier f UL3 Figure 2B shows different spectrum allocations for three component carriers. Although carrier aggregation is often described in the context of aggregating It may be used to aggregate more or fewer carriers. Although shown in Figure 1, the aggregation scenario also It is also applicable to

[0081] The first carrier aggregation scenario 31 is for adjacent frequencies in a common frequency band. This shows in-band contiguous carrier aggregation where multiple component carriers are aggregated. For example, the first carrier aggregation scenario 31 is a contiguous and first frequency band BAN Component carrier f located in D1 UL1 , f UL2 and f UL3 Drawing the aggregation of Ku.

[0082] Continuing to refer to FIG. 13B, the second carrier aggregation scenario 32 is Contiguous carrier aggregation, where the frequencies are non-contiguous but in a common frequency band Two or more component carriers within the same carrier group are aggregated. For example, the second carrier The aggregation scenario 32 is located in a first frequency band BAND1, but is discontinuous. Component carrier f UL1 , f UL2 and f UL3 Draw the aggregation of.

[0083] The third carrier aggregation scenario33 is non-contiguous carrier aggregation within the band. Here, component carriers in non-adjacent frequency bands are For example, the third carrier aggregation scenario 33 is a first frequency band B AND1 component carrier f UL1 and f UL2 and the second frequency band BAND2 Component carrier f UL3 It depicts the convergence of

[0084] FIG. 2C illustrates various downlink carrier aggregation schemes for the communication link of FIG. 2A. Examples are shown below. These examples are for the first component carrier f DL1 , the second component Carrier f DL2 , third component carrier f DL3 , 4th component carrier f DL4 , and the fifth component carrier f DL5 for different spectrum allocations , depicting various carrier aggregation scenarios 34-38. Figure 2C shows the five components. Although it is described in the context of aggregating component carriers, A downlink may be used to aggregate more or fewer carriers. Although presented in the context of a downlink, the aggregation scenario It is also applicable to the uplink.

[0085] The first carrier aggregation scenario 34 is a scenario in which carriers are arranged contiguously within the same frequency band. Additionally, a second carrier aggregation scenario is also proposed. Rio 35 and the third carrier aggregation scenario 36 are discontinuous but on the same frequency. Two examples of intra-band aggregation are shown. In addition, a fourth carrier aggregation scenario is also shown. The Rio37 and 5th Carrier Aggregation scenarios38 are non-adjacent and multi-band. 1 shows two examples of aggregation in which component carriers in a wavelength band are aggregated. As the number of aggregated component carriers increases, the number of possible carrier aggregation The complexity of the scenario also increases.

[0086] 2A to 2C, individual components used in carrier aggregation are shown. The component carriers may have different frequencies, e.g., frequency carriers in the same band or multiple bands. Additionally, carrier aggregation can include individual component carriers. In this example, the rear carriers are approximately the same bandwidth, and individual component carriers are different bandwidths. It is applicable to implementations with width.

[0087] A given communications network assigns a particular user device a primary communication Component Carrier (PCC) or anchor carrier and PCC for downlink Additionally, a mobile device may allocate a single frequency key for uplink or downlink. When communicating using a carrier, the user device communicates using the PCC. To increase the bandwidth for link communication, an uplink PCC can be configured to connect to one or more uplink It can be aggregated with a secondary component carrier (SCC). To increase the bandwidth for downlink communications, a downlink PCC may be configured to connect one or more downlink It can be aggregated with the Downlink SCC.

[0088] In a given implementation, the communication network may provide a network Additionally, the primary cell may operate using a PCC while The secondary cell may operate using the SCC. The primary cell and the secondary cell may For example, different coverage areas may occur due to differences in carrier frequencies and / or network environments. It has a boundary area.

[0089] Licensed Assisted Access (LAA) refers to the use of licensed frequencies associated with a mobile operator. Carriers will be aggregated with unlicensed spectrum frequency carriers like Wi-Fi Downlink Carrier Aggregation (LAA) is a downlink carrier aggregation (LAA) associated with a communication link. downlink PCC in the licensed spectrum carrying control and signaling information While unlicensed spectrum is used for wide downlink bandwidths when available, LAA aims to circulate Wi-Fi users by dynamically adjusting secondary carriers. It can operate to avoid and / or coexist with Wi-Fi users. Enhanced Authorization Assisted Access (eLAA) refers to the use of both downlink and uplink authorized It is called an evolution of LAA, which aggregates unlicensed spectrum.

[0090] Dual Connection

[0091] With the introduction of the 5G NR air interface standard, 3GPP is working to ease the transition. It allows simultaneous operation of 5G and 4G standards. This mode is called non-standalone (N on-Stand-Alone (NSA) 5G operation or E-UTRAN New Radio ( New Radio Dual Connectivity (EN-DC) Also referred to as 4G and 5G carriers, both are transmitted simultaneously from the user equipment (UE). EN-DC can present harmonic rejection challenges. The filter should be implemented to provide harmonic rejection in dual-connection applications. The radio frequency front-end architecture disclosed herein is suitable for dual connectivity applications. It can be implemented in applications.

[0092] In a given EN-DC application, the dual connectivity NSA will be able to connect to the existing 4G core network. This involves overlaying a 5G system on a network. For dual connectivity in 4G, control and synchronization between base station and UE is provided by 4G network. While this can be done, 5G networks will be able to provide complementary services tethered to 4G anchors. 4G anchor is a 5G data / control overlay. It can connect to existing 4G networks.

[0093] Figure 3 is a diagram of an example of a dual-connection network topology. This architecture: LTE legacy coverage to ensure continuity of service provision and gradual rollout of 5G cells The UE30 can utilize dual uplinks for both LTE and NR carriers. The UE 30 can transmit uplink LTE carrier Tx1 simultaneously. while transmitting uplink NR carrier Tx2 to gN Dual connectivity can be implemented by transmitting the signal to the gNB (gNB) 32. In one example of a network topology, uplink carriers Tx1, Tx2 and / or transmits any suitable combination of downlink carriers Rx1, Rx2 over the radio link. The eNB31 is a core like the Evolved Packet Core (EPC) that can transmit simultaneously. The gNB32 can provide a connection to the core network via the eNB31. It can communicate with the network. Control plane data is transmitted between the UE30 and the eNB. The eNB 31 can also communicate with the control plane data It can also communicate data to the gNB32.

[0094] In the example of the dual connection topology of FIG. 3, the standard band and the radio access technology (e.g., FD It can transmit and receive wirelessly any suitable combination of This is related to having multiple separate radios and bands functioning in the UE 30. According to TDD LTE anchor points, Clock operation is synchronous when the operating modes are limited to Tx1 / Tx2 and Rx1 / Rx2. This may involve Tx1 / Tx2, Tx1 / Rx2, Rx1 / Tx2, and Rx1 / Rx2. When the LTE anchor is a frequency division duplex (FDD) carrier, T DD / FDD in-band operation is simultaneous with Tx1 / Rx1 / Tx2 and Tx1 / Rx1 / Rx2 may be involved in

[0095] Tunable filter for harmonic rejection

[0096] Harmonic rejection can be implemented in a variety of tunable filters. Examples of possible filter embodiments are described with reference to FIGS. Any suitable combination of features of the exemplary filter implementations may be implemented together. Cut.

[0097] In 5G NR and other applications, harmonic rejection is becoming more difficult to achieve. By providing additional tuning possibilities for the filter, such harmonics can be This helps meet rejection specifications. The embodiments disclosed herein provide At least one tunable impedance circuit to provide tunability The present invention relates to a filter having a mutually coupled inductor and one or more switches. at least one tunable impedance circuit having a switch; The inductor provides more harmonic rejection than a similar filter without the mutually coupled inductor. This allows for a tunable impedance compared to previous designs without mutually coupled inductors. The tuning possibilities for multiple harmonics depend on the number of switches included in the dance circuit. In the filter embodiments disclosed herein, due to mutual inductive coupling, It is possible to achieve two or three times as many harmonic states as a similar filter without The principles and advantages disclosed herein can be included in tunable impedance circuits. The principles disclosed herein can be applied to a number of harmonics greater than the number of switches. The advantages are not limited to harmonic rejection, but may include any other suitable out-of-band rejection and / or noise rejection. It can also be applied to a filter.

[0098] FIG. 4 is a schematic diagram of a tunable filter 40 according to one embodiment. The filter 40 is configured to filter radio frequencies propagating between a first port P1 and a second port P2. The tunable filter 40 is arranged to filter a number of signals. As shown, the tunable filter 40 may be a tunable The functional impedance circuit 42 includes an inductor and a capacitor. The frequency of the tunable filter 40 is controlled by the capacitance of the capacitor. This setting affects the frequency response for harmonic rejection. Including which frequencies pass and where the notches are located.

[0099] The inductors of the tunable filter 40 are a first inductor L1 and a second inductor L2. The first inductor L1 and the second inductor L2 are connected in series with each other. The inductor L1 and the second inductor L2 are mutually coupled to each other. The first inductor L1 and the second inductor L2 are The tunable filter 40 and / or one or more of the tunable filters disclosed herein have a coupling coefficient K. Other tunable filter inductors include one or more surface mount technology (SMT) inductors. duct, one or more coils embedded on and / or within a substrate (e.g., a laminate substrate), The above on-die inductors (e.g., switch in tunable impedance circuits) one or more inductors on the same die as the switch), one or more integrated passive devices (IPDs) Any suitable inductor, such as an inductor, etc., or any suitable combination thereof. may include:

[0100] The capacitors of the tunable filter 40 are connected to a tunable impedance circuit 42 capacitors C 11 , C 12 , …, C 1N and capacitors C2 and C3. The disclosed tunable filter 40 and / or one or more other tunable The filter capacitors may consist of one or more surface mount technology (SMT) capacitors, one or more on-chip capacitors, capacitor (e.g., the same diode as the switch in a tunable capacitance circuit) one or more capacitors on the IPD), one or more IPD capacitors, or the like, or any suitable The capacitors may include any suitable capacitors, such as a combination.

[0101] In the tunable filter 40, the tunable impedance circuit 42 Tunable capacitance circuit. Tunable impedance circuit 42 is in parallel with the first inductor L1 in the tunable filter 40. The tunable impedance circuit 42 is a second inductor in the tunable filter 40. The tunable impedance circuit 42 is in series with a plurality of capacitors C 11 , C 12 , …, C 1N Each of these capacitors is connected to a switch S 11 , S 12 , …, S 1N Each is connected in series with a switch S 11 , S 12 , …, S1 N are capacitors C 11 , C 12 , …, C 1N Connect one end of each to the first inductor. Therefore, the switch S 11 , S 12 , …, S1 N are capacitors C 11 , C 12 , …, C 1N These are the first inductor L 1 in parallel with the first inductor L1. The capacitor or capacitors electrically coupled in this manner form a tunable impedance Sets the effective capacitance for one particular state of the circuit 42.

[0102] Although the embodiments disclosed herein may include tunable capacitance circuits, Regardless, any pertinent principles and advantages disclosed herein may be utilized in conjunction with tunable impedance Such a tunable impedance circuit can be applied to The circuit may include a tunable inductance circuit. Any suitable inductor can be used in the filter, including tunable inductance circuits that filter out harmonics. This can be implemented by tuning the rejection. The tunable filter comprises one or more tunable capacitance circuits; and It may include one or more tunable inductance circuits.

[0103] The tunable filter 40 is arranged to provide harmonic rejection. The location of the harmonic notches in the frequency response of the tunable filter 40 can be controlled by a tunable inverter. Tuning can be performed based on the state of the impedance circuit 42. For example, S 11 By closing the capacitor C 11 is connected in parallel to the first inductor L1. This allows the tunable impedance circuit 42 to The effective capacitance given by the filter and the tunable filter 40 for harmonic rejection The notch position in the frequency domain changes. Thus, by toggling the switches of the tunable impedance circuit 42, The filter response has more notch locations than a similar filter without mutually coupled inductors. can be adjusted.

[0104] The illustrated tunable filter 40 includes a T-network. A first parallel inductor including a first inductor L1 and a tunable impedance circuit 42 a second inductor-capacitor circuit, a shunt capacitor C3, a second inductor L2 and a capacitor and a second parallel inductor-capacitor circuit including a capacitor C2. The appropriate principles and advantages may be applied to any other suitable filter topology.

[0105] FIG. 5 is a schematic diagram of a tunable filter 50 according to one embodiment. The tunable filter 50 is similar to the tunable filter 40 of FIG. It differs in that it includes a parallel inductor-capacitor circuit and an additional shunt capacitor. An additional parallel inductor-capacitor circuit is provided, consisting of a third inductor L3 and a capacitor C4. An additional shunt capacitor C5 is included in the additional inductor-capacitor circuit. and the first inductor L1. As shown in FIG. The first inductor L1 is mutually coupled to both the second inductor L2 and the third inductor L3. The inductor L1 and the second inductor L2 have a coupling coefficient K 12 The first inductor L1 and the third inductor L2 are The inductor L3 is the coupling coefficient K 31 The tunable filter 50 has By changing the state of the switch of the tuning impedance 42, the tuning Frequency response of tunable filter 50 with mutual inductive coupling of tunable filter 50 The positions of the three notches corresponding to the harmonics in can be varied.

[0106] FIG. 6 is a schematic diagram of a tunable filter 60 according to one embodiment. The tunable filter 60 is similar to the tunable filter 50 of FIG. 5, but with each parallel The column inductor-capacitor circuit includes a corresponding tunable impedance circuit. The difference is that the multiple inductors are mutually coupled. Although it includes an inductor-capacitor circuit, it may contain any suitable number of inductors and capacitors. A sigma circuit may be implemented.

[0107] As shown in FIG. 6, the tunable impedance circuits 42, 52 and 62 are Each of these tuning Each of the variable impedance circuits 42, 52 and 62 has a corresponding inductor L1 , L2, L3 can be adjusted.

[0108] The tunable impedance circuit 52 is configured to The tunable impedance circuit 52 is connected in parallel with the second inductor L2. Capacita C 11 , C 12 , …, C 1N Each of these capacitors is Chi S 11 , S 12 , …, S 1N Each is connected in series with a switch S 21 , S 22 , …, S 2N are the corresponding capacitors C 21 , C 22 , …, C 2N The second industrial Therefore, the switch S 21 , S 22 ,..., S 2N are capacitors C 21 , C 22 , …, C 2N Each of them is the second inductor. The capacitor L1 may be selectively electrically coupled to be in parallel with capacitor L2.

[0109] The tunable impedance circuit 62 is The tunable impedance circuit 62 is connected in parallel with the third inductor L3. Capacita C 41 , C 42 , …, C 4N Each of these capacitors is Chi S 41 , S 42 , …, S 4N Each is connected in series with a switch S 41 , S 42 , …, S 4N are the corresponding capacitors C 41 , C 42 , …, C 4N The third industrial Therefore, the switch S 41 , S 42 ,..., S 4N are capacitors C 41 , C 42 , …, C 4N Each of them is the third induction The resistor L1 may be selectively electrically coupled to be in parallel with the resistor L3.

[0110] In the tunable filter 60, a first inductor L1, a second inductor L2, and is the coupling coefficient K 12 The second inductor L2 and the third inductor L3 have a coupling coefficient K 23 The first inductor L1 and the third inductor L3 have a coupling coefficient K 13 have. Mutually coupled inductors L1 and L3 are used in tunable filter 60. This provides additional cross-coupling for the tunable filter 50.

[0111] FIG. 7 is a schematic diagram of a tunable filter 70 according to one embodiment. The tunable filter 70 is similar to the tunable filter 60 of FIG. The input capacitors C3 and C5 are connected to the tunable impedance circuits 72 and 74 and FIG. 7 illustrates how the principles and advantages disclosed herein are implemented in a high-order filter. Indicates that the rule applies to the filter.

[0112] The tunable impedance circuit 72 includes a plurality of capacitors C 31 , C 32 ,..., C 3N Each of these capacitors is connected to a switch S 31 , S 32 , …, S 3N Each is connected in series with a switch S 31 , S 32 , …, S 3N Each corresponds to Capacitor C 31 , C 32 , …, C 3N The first inductor L1 and the second inductor L2 Therefore, the switch S 31 , S 32 , …, S 3N are the corresponding capacitors C 31 , C 32 , …, C 3N Shunt The semiconductor laser may be selectively electrically coupled to the semiconductor laser.

[0113] The tunable impedance circuit 74 includes a plurality of capacitors C 51 , C 52 , …, C 5N Each of these capacitors is connected to a switch S 51 , S 52 , …, S 5N So The switch S 51 , S52 , …, S 5N Each corresponds to Capacitor C 51 , C 52 , …, C 5N The second inductor L2 and the third inductor L3 are Therefore, the switch S 51 , S 52 , …, S 5N Each corresponds to a capacitor C 51 , C 52 , …, C 5N , nodes and groups The electrodes can be selectively electrically coupled to the lands.

[0114] FIG. 7 illustrates a method for incorporating series and / or shunt capacitors into a tunable impedance circuit. In a given application, one or more of the filters may be implemented by The capacitor may be implemented by one or more tunable capacitance circuits. Alternatively, one or more of the capacitors of the filter may be fixed and not tunable. The tunable filter may also be implemented by any suitable capacitor. The capacitor may be a tunable capacitor according to any suitable principles and advantages disclosed herein. Alternatively or additionally, the filter may be implemented by a tunable filter. Any suitable inductor of the filter may be used in accordance with any suitable principles and advantages disclosed herein. This can be implemented by a tunable inductance circuit. By adjusting the capacitance and / or inductance with an impedance circuit, The harmonic rejection of the tunable filter can be tuned by using the

[0115] In a given application, one or more inductors may be connected to one or more shunts. By including a counter capacitor in series with the counter capacitor, one or more harmonic traps can be formed. Such a shunt inductor may be cross-coupled with one or more series inductors. FIG. 8A shows an example of a shunt inductor arranged in series with a shunt capacitor. Here, the shunt inductor is mutually coupled to a plurality of inductors in series.

[0116] FIG. 8A is a schematic diagram of a tunable filter 80 according to one embodiment. The tunable filter 80 is similar to the tunable filter 40 of FIG. A shunt inductor L in series with shunt capacitor C3 S The difference is that it includes a shunt. Inductor L S are mutually coupled to the first inductor L1 and the second inductor L2. Inductor L1 and shunt inductor L S is the coupling coefficient K 1S The second inductor L2 and shunt inductor L S is the coupling coefficient K 2S It has.

[0117] FIG. 8B is a schematic diagram of a tunable filter 80' according to one embodiment. Tunable filter 80' is similar to tunable filter 80 of FIG. 8A. However, the difference is that the second inductor L2 and the second capacitor C2 are not included. The tunable filter 80' is a first filter in which the impedance in the tunable filter 80 is zero. It is equivalent to a second inductor L2 and a second capacitor C2 with zero impedance. In the filter 80, the second inductor L2 and the second capacitor C2 are has a non-zero impedance.

[0118] FIG. 8C is a graph of the frequency response of tunable filter 80' of FIG. 8B. The capacitor C 11 , C 12 , C 13 and C 14 are connected in series to 4 switches S 11 , S 12 , S 13 and S 14 a tunable capacitor having As an example, the frequency response of a tunable filter 80' may be The tunable filter 80' shown in FIG. 8C can provide the following harmonic rejection: That is, the second harmonic of band 8, the third harmonic of band 8, the third harmonic of band 12, Harmonics, Band 13 / Band 14 second harmonics, Band 20 / Band 26 third harmonics, The second harmonic of band 28, the third harmonic of band 28, and the third harmonic of band 71. The tunable filter 80' corresponding to the frequency response in FIG. The effective capacitance C1 of the variable capacitance circuit 42 is adjusted to cover the harmonic specifications. It is designed to move the two notches in opposite directions when switched.

[0119] FIG. 9 is a schematic diagram of a tunable filter 90 according to one embodiment. The tunable filter 90 is similar to the tunable filter 40 of FIG. The tunable filter 90 is a tunable filter that replaces the tunable impedance circuit 42. 1. The difference is that it has a tunable impedance circuit 92. The impedance circuit 92 provides an effective capacitance C1. The circuit 92 is arranged to adjust the capacitance in parallel with the first inductor L1. The tunable impedance circuit may be any suitable tunable impedance circuit. The tunable impedance circuit 92 may be the tunable impedance circuit 42 As another example, the tunable impedance circuit 92 may vary the capacitance based on the applied voltage. The impedance may be a tunable impedance circuit that includes a varactor to vary the impedance. A technical description and an example embodiment will be described with reference to FIG.

[0120] Without being bound by theory, a theoretical explanation for the tunable filter 90 will be presented. For bandwidth design, ω C is the central angular frequency. Neglecting the capacitance of C2, both ports P1 and P2 of the tunable filter 90 Assuming Z0=50Ω, the inductance of the first inductor L1 and the second inductor L2 is The inductances of both capacitors are equal to L, and the capacitance of the third capacitor C3 according to Equation 1 is Capacitance C3 corresponds to simultaneous conjugate matching.

number

[0121] According to Equation 2, the harmonic notch ω can be found.

number

[0122] Select an appropriate coupling coefficient K for each of the first inductor L1 and the second inductor L2. By this, the first capacitor C1 (and / or the second capacitor C2 and / or the third capacitor Adjust the capacitance of capacitor C3 so that both harmonic notches are tuned to the desired frequency. Alternatively or additionally, the inductance of the first inductor L1 can be tuned as follows: and / or the inductance of the second inductor L2, so that both harmonic notches are desired. The tunable filter can be tuned to adjust the frequency of The 90 inductor-capacitor tank also resonates at several other frequencies. These notches can be located at frequencies other than multiples of the fundamental frequency, so that There can be.

[0123] We define σ by Equation 3.

number

number

[0124] When δ=0, the two notches are infinitely spaced apart. When δ=1, the two notches are The function σ(δ) is a monotonically increasing smooth function with the same domain and range [0,1]. It is a function.

[0125] ω ± From this formula, the following is derived:

number

[0126] The capacitances of the second and third capacitors C2 and C3 are fixed, and the capacitance of the first inductor If the inductances of the first and second inductors L1 and L2 are fixed, The capacitance of the capacitor C1 and the capacitance between the first inductor L1 and the second inductor L2 are The mutual coupling M remains as a design variable. When the capacitance of the first capacitor is C1 = 0 , from Equation 4, σ = δ = 0 is obtained. Seeking the solution for σ = 1, the following is obtained.

Equation

[0127] This can be rewritten as follows.

Equation

[0128] For the second approximation, M 2 Assuming <<L1L2, the discriminant of Equation 6 is obtained as follows .

Equation

[0129] This means that by selecting an appropriate M,

Equation

[0130] Assuming that σ from Equation 3 is fixed for any capacitance of the second capacitor C2 the mutual coupling M and the capacitance of the first capacitor C1 can be determined .

[0131] The following is obtained from Equation 4.

Equation

[0132] Equation 8 can be rewritten as follows.

Number

[0133] If the capacitance of the first capacitor C1 is unknown, Equation 9 has the following discriminant (M 2 <<Assume L1L2 is an assumption).

Number

[0134] (1 - σ)L2C2 > MC3 as long as M is selected, the capacitance of the first capacitor C1 has two (positive) solutions that satisfy a specific σ. These two solutions can be found from Equation 11 below below.

Number

[0135] In fact, when the capacitance of the first capacitor C1 varies from C 1- to C 1+ until , <00​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ If so, both notches indicate that the capacitance of the first capacitor C1 increases. In addition,

number

number

[0138] The coupling coefficient between the first inductor L1 and the second inductor L2 of the tunable filter 90 is Figure 10 shows the relationship between the distance between the first inductor L1 and the second inductor L2. The mutual coupling of two inductors is shown in Fig. 1. This can be achieved using SMT inductors. This is achieved by two properly aligned embedded coils in the laminate or on-die. FIG. 10 shows the first inductor L1 and 10 is a plot of the magnitude of the coupling coefficient for one embodiment of the second inductor L2, where The first inductor L1 and the second inductor L2 each have a capacitance of 2.7 nanohenries (nH). Figure 10 shows how the physical layout of the inductors affects the mutual coupling. It is shown that the mutual coupling can be influenced by the distance between the inductors. The geometry of the coupling inductors can also affect the mutual coupling.

[0139] The coupling coefficient also typically depends on the polarity of the mutually coupled inductors. By switching the polarity of the coupled inductors, the sign of the coupling coefficient can be changed (e.g., from positive to negative or vice versa). The black circle of the inductor shown in the drawing indicates this The polarity of these inductors is shown.

[0140] We will now describe a first example design for the tunable filter 90 of Figure 9. In this example, The tunable filter 90 comprises two different tunable impedance circuits 92. Two operating frequencies (1 GHz and Each state has a 2fo rejection > 25 decibels (dB) and a 3fo rejection > 25 decibels (dB). The rejection is >35 dB, where 2fo rejection is the second harmonic rejection and 3fo rejection is the third harmonic rejection. The first inductor L1 and the second inductor L2 are 20 in this example. It is assumed to have a constant quality factor (Q) that is proportional to the impedance of the tunable impedance circuit. 2 is the first effective capacitance C when operating at 1 GHz. 1A is given, 0.9GH When operating at z, the second effective capacitance C 1B and / or To achieve these performance specifications, tunable filters are used. Data 90 may include components having values ​​shown in Table 1 below. [Table 1]

[0141] FIG. 11 shows the harmonic structure of the tunable filter 90 of FIG. 9 designed according to the first design example. 11 is a graph of a simulation showing the location of the wave notch. The second curve in Figure 11 shows the location of the second and third harmonic notches for operation at , the positions of the second and third harmonic notches are shown for operation at 0.9 GHz. These curves show the performance of the tunable impedance circuit 92 for two different operating frequencies. tunable filter 90 by varying the effective capacitance of The positions of the two notches in the frequency response of the tunable impedance are shown. The impedance circuit 92 is configured to change the state of the tunable impedance circuit 92. and arranged to selectively electrically couple one end of the capacitor to the first inductor L1. A change in the state of the switch changes the frequency of the tunable filter 90. The position of the two notches in the signal response can vary.

[0142] We now turn to a second design example for the tunable filter 90 of Figure 9. In this example, The tunable filter 90 comprises three different tunable impedance circuits 92. Three operating frequencies (1 GHz, 0.9GHz and 0.8GHz). Each state has 2fo rejection >25dB and 3fo rejection >25dB. It has a rejection >35dB. Inductors L1 and L2 have a constant Q of 20 in this example. The tunable impedance circuit 92 is assumed to operate at 1 GHz. When the first effective capacitance C1A Given the second real time sine wave, the second real time sine wave is generated when operating at 0.9 GHz. Effective capacitance C 1B is given, and the third effective capacitor is ance C 1C These properties can be adjusted and / or switched to provide To achieve the performance specifications, the tunable filter 90 has the values ​​shown in Table 2 below. It may include a component that: [Table 2]

[0143] FIG. 12 shows the harmonic structure of the tunable filter 90 of FIG. 9 designed according to the second design example. 12 is a graph of a simulation showing the location of the wave notch. The second curve in Figure 12 shows the location of the second and third harmonic notches for operation at , the locations of the second and third harmonic notches for operation at 0.9 GHz are shown. The third curve in Figure 2 shows the positions of the second and third harmonic notches for operation at 0.8 GHz. These curves show the tunable impedance for three different operating frequencies. tunable by varying the effective capacitance of the dance circuit 92. 1 shows the locations of two notches in the frequency response of the tuner filter 90. The tunable impedance circuit 92 changes the state of the tunable impedance circuit 92. and selectively electrically coupling one end of the capacitor to the first inductor L1 so as to vary the The switch includes a switch arranged to change the state of the tunable filter. The location of the two notches in the frequency response of filter 90 can be varied.

[0144] FIG. 13 is a schematic diagram of a tunable filter 130 according to one embodiment. Tunable filter 130 is similar to tunable filter 50 of FIG. The tunable filter 130 replaces the tunable impedance circuit 42. 1. The difference is that it has a tunable impedance circuit 92.

[0145] A third design example will now be described with reference to tunable filter 130. In this example, The tunable filter 130 is a two-phase tunable impedance circuit 92. Two operating frequencies (1G) can be achieved by switching between different effective capacitance values. Hz and 0.9GHz). Each state has 2fo rejection > 30dB, 3fo rejection > 50 dB, and 4fo rejection >60 dB, where 2fo rejection is the second harmonic rejection , 3fo is the third harmonic rejection, and 4fo is the fourth harmonic rejection. L2 is assumed to have a constant Q, which in this example is 20. The capacitance circuit 92 has a first effective capacitance C 1A is given When operating at 0.9 GHz, the second effective capacitance C 1B Adjusted to give To achieve these performance specifications, The filter 130 is a component filter having the values ​​shown in Tables 3A and 3B below. It may include [Table 3A] [Table 3B]

[0146] FIG. 14 illustrates the tunable filter 130 of FIG. 13 designed according to the third design example. 14 is a graph of a simulation showing the location of harmonic notches. The positions of the second, third and fourth harmonic notches are shown for operation in Hz. The second curve of 14 is the second, third and fourth harmonics for operation at 0.9 GHz. These curves show the position of the notches in the waveform. by varying the effective capacitance of the tunable impedance circuit 92. The locations of three notches in the frequency response of tunable filter 130 are shown.

[0147] A filter design is disclosed that achieves Mx2N harmonic states with N switches. where M is an integer greater than or equal to 2. The filter designs disclosed herein are harmonic tuned. Use inductive mutual coupling to increase the number of possible states. Design example with M=2 (Design example 1 and Design example 2) Design Example 2), and M=3 (Design Example 3) are described. Although related to filters, any of the relevant principles and advantages disclosed herein may be used in conjunction with high Other filters such as bandpass filters and / or bandstop filters It can be implemented for any type of filter.

[0148] The principles and advantages disclosed herein can be implemented in a variety of filters, for example: The filters disclosed herein may be inelastic filters that include passive impedance elements. Alternatively, the filters disclosed herein may include: In a given application, one or more acoustic wave resonators may be used together with inductive components and It may also be included in a hybrid filter that includes inductive and capacitive components. The components and capacitive components are in the passband or The filter can set the stopband, and one or more acoustic wave resonators can be used for the hybrid filter. This allows one or more relatively steep band edges to be achieved.

[0149] Radio frequency system with tunable filter

[0150] The tunable filters disclosed herein are suitable for use in wireless applications such as radio frequency front ends. Any suitable principles and advantages disclosed herein may be included in the line frequency system. Such tunable filters may be used in combination with the harmonic rejection provided by the filters disclosed herein. It can be implemented in any suitable location in the system that can benefit from the stop.

[0151] FIG. 15A shows a schematic diagram of a radio frequency system 150 having a tunable filter 152. As shown in FIG. 15A, a tunable filter 152 is coupled between the antenna switch 154 and the antenna 155. The filter 152 is a filter for detecting radio frequencies propagating between the antenna switch 154 and the antenna 155. According to any suitable principles and advantages disclosed herein, to provide harmonic rejection to a signal. This can be implemented as follows.

[0152] FIG. 15B shows a schematic diagram of a radio frequency system 156 having a tunable filter 157. As shown in FIG. 15B, the tunable filter 157 is coupled between the power amplifier 158 and the band select switch 159. 159 converts the output of the power amplifier 158 into a radio frequency signal path for a particular operating band. Such a radio frequency signal path may have a passband corresponding to the operating band. The band select switch 159 may include a band pass filter having a tunable The filter 157 may be selectively electrically connected to a selected radio frequency signal path. The tunable filter 157 is an example of a multi-throw switch that can be used to Harmonic rejection for radio frequency signals propagating between the output of 8 and the band select switch 159 It can be implemented in accordance with any suitable principles and advantages disclosed herein to provide do.

[0153] wireless communication devices

[0154] The tunable filters disclosed herein are suitable for use in wireless communication devices such as mobile devices. The invention may be included in one or more of the following methods according to any suitable principles and advantages disclosed herein: The tunable filter may be implemented in any suitable wireless communication device. An example of such a wireless communication device is described with reference to FIG.

[0155] FIG. 16 is a schematic diagram of one embodiment of a mobile device 800. The figure includes a baseband system 801, a transceiver 802, a front-end system 803, an amplifier a power management system 805; a memory 806; a user interface 807; Includes a battery 808.

[0156] The mobile device 800 may be 2G, 3G, 4G (LTE, LTE Advanced, and LTE Advanced). Advanced Pro), 5G NR, WLAN (e.g., Wi-Fi), WPAN (e.g., Bluetooth (registered trademark) and ZigBee (registered trademark), WMAN (e.g., Wi Max), and / or use a variety of communication technologies, including but not limited to GPS technology. can be used to communicate with

[0157] The transceiver 802 generates an RF signal for transmission and receives an input from an antenna 804. It will be appreciated that the various aspects of the present invention relate to the transmission and reception of RF signals. The various functions may be implemented by one or more components collectively represented in FIG. 16 as transceiver 802. In one example, separate RF signal processors are provided to handle certain types of RF signals. The components (eg, separate circuits or dies) may be provided.

[0158] The front-end system 803 transmits to the antenna 804 and / or to the antenna 80 4. In the illustrated embodiment, The front-end system 803 includes an antenna tuning circuit 810, a power amplifier (PA) 8 11, a low noise amplifier (LNA) 812, a filter 813, a switch 814, and a signal splitter / combining circuit 815. However, other implementations are possible. One or more tuning elements with harmonic rejection including one or more features of the embodiments disclosed herein. The filter may include a tunable filter.

[0159] For example, the front-end system 803 may include signal amplification for transmission, amplification of received signals, Filtering signals, switching between different bands, switching between different power modes switching between transmit and receive modes, duplexing signals, multiplying signals Dualplexing (e.g., diplexing or triplexing), or any of these A number of functions can be provided, including but not limited to any combination thereof.

[0160] In certain implementations, the mobile device 800 supports carrier aggregation. This allows for flexibility to increase peak data rates. is a combination of frequency division duplexing (FDD) and time division duplexing (TDD). It can be used for both single and multiple carriers or channels. Carrier aggregation is the aggregation of adjacent carriers within the same operating frequency band. Carrier aggregation may also be discontinuous, within a common band or Frequencies in different bands may include separate carriers.

[0161] Antenna 804 may include antennas used for a wide variety of types of communications. For example, the antenna array 804 may receive signals associated with a wide variety of frequencies and communication standards. The signal may include an antenna for transmitting and / or receiving.

[0162] In certain implementations, antennas 804 may be used for MIMO communications and / or switched diversity communications. For example, MIMO communication uses a single radio frequency channel. MIMO communication uses multiple antennas to transmit multiple data streams via a single antenna. may be used to achieve high signal-to-noise ratios, improved coding, and / or spatial multiplexing in wireless environments. The benefit of switched diversity is the reduction of signal interference due to signal timing differences. Refers to communications where a particular antenna is selected to operate at a particular time. based on various factors such as bit error rate and / or signal strength indicators. A switch can be used to select a particular antenna from the group of antennas.

[0163] The mobile device 800 may, in certain implementations, operate with beamforming. For example, the front-end system 803 may be configured to transmit and receive signals using an antenna 804. controllable to provide beam formation and directionality for transmission and / or reception purposes amplifiers with gain and phase shifters with controllable phase. In this context, the amplitude and phase of the transmit signal applied to antenna 804 The signals emitted from the antenna combine using constructive and destructive interference and propagate in a given direction. The signal strength is controlled to generate an aggregate transmit signal indicative of the beam quality of the transmitted signal. In the context of reception, amplitude and phase are determined by the signal arriving at antenna 804 from a particular direction. In a given implementation, the signal energy is controlled to be received when the , the antenna 804 may include one or more of a plurality of antenna elements for improved beamforming. Contains an array of

[0164] The baseband system 801 receives various user input / output (I / O) signals such as voice and data. The baseband system is coupled to a user interface 807 to facilitate processing of the 801 represents a digital representation of a transmit signal that a transceiver 802 generates an RF signal for transmission. The baseband system 801 also provides the transceiver 802 with As shown in Figure 16, the baseband system processes a digital representation of the received signal. The system 801 is coupled to memory 806 to facilitate operation of the mobile device 800 .

[0165] The memory 806 may be used to facilitate operation of the mobile device 800 and / or to store user information. for a wide variety of purposes, such as storing data and / or instructions to provide storage of can be used for

[0166] The power management system 805 provides a number of power management functions for the mobile device 800. In a specific implementation, the power management system 805 controls the supply voltage of the PA supply control unit 811. For example, the power management system 805 may include control circuits for efficiency such as power added efficiency (PAE). to vary the supply voltage applied to one or more of the power amplifiers to improve efficiency. It can be configured.

[0167] As shown in FIG. 16, the power management system 805 receives the battery voltage from the battery 808. The battery 808 may be any suitable battery for use in the portable device 800. Often, this includes, for example, lithium-ion batteries.

[0168] Applications, Terminology, and Conclusion

[0169] Any of the above-described embodiments may relate to a mobile device such as a cellular handset. The principles and advantages of the embodiments may be implemented in any of the embodiments described herein. Any system, such as any uplink wireless communication device, that may benefit from The teachings herein are applicable to a variety of systems. Although the present disclosure includes example embodiments, the teachings described herein may be applied to various configurations. All of the principles and advantages described herein can be applied to frequencies in the range of about 30 kHz to 300 GHz, such as the range of 100 kHz to 8.5 GHz. The present invention may be implemented in association with RF circuitry configured to process signals having The disclosed tunable filters may be configured to operate at frequencies within FR2 of the 5G NR specification, for example. RF signals at frequencies up to and including millimeter wave frequencies, such as You can filter the number.

[0170] Aspects of the present disclosure can be implemented in a variety of electronic devices. Examples include consumer electronic products, packaged radio frequency modules, and components, radio frequency filter dies, uplink wireless communication devices, wireless communication infrastructure Examples of electronic devices include, but are not limited to, smart structures, electronic test equipment, etc. mobile phones such as smart phones, smart watches or wearable devices such as earpieces Computing devices, telephones, televisions, computer monitors, computers, models computers, handheld computers, laptop computers, tablet computers, Microwave ovens, refrigerators, automotive electronic systems, industrial robots, etc. Una robot, Internet of Things device, stereo system, digital music players, radios, cameras such as digital cameras, portable memory chips, washing machines or This includes, but is not limited to, household appliances such as dryers, peripheral devices, watches, clocks, etc. Additionally, electronic devices may include unfinished products.

[0171] Throughout this specification and claims, unless the context indicates otherwise: The terms "comprise," "include," "includes," and the like are used to imply inclusion as opposed to an exclusive or exhaustive meaning. It should be interpreted in a general sense, i.e., "including but not limited to." In particular, "can," "could," "may," "may," "for example," "of Conditional language herein, such as "such" and the like, is generally used unless specifically stated otherwise. or unless the context of use indicates otherwise, a given embodiment may be used in conjunction with a given feature. to convey that some embodiments include features, elements, and / or states while other embodiments do not. The word "coupled" as generally used herein means directly connected or connected to one or more Refers to two or more elements that may either be connected through an intermediate element. The word "connected" as generally used herein means directly connected or through one or more intermediate elements. In addition, the word "here" refers to two or more elements that may be connected in any way. The words "upper," "lower," and similar imports, when used in this application, refer to this application as a whole. and does not refer to any particular part of this application. Each term in the above detailed description using the terms "a," "b," "c," "d," "e," "f," "g," "h," "i," "j," "j," "j," "j, "k ...j, "k," "j, "j, "j, "j, "j, "j, "j, "j,

[0172] While certain embodiments have been described, it should be understood that these embodiments are presented by way of example only. It is not intended to limit the scope of the present disclosure. The novel filters, wireless communication devices, apparatus, methods, and systems may be embodied in a variety of other forms. Furthermore, the filters, wireless communication devices, and apparatuses described herein may be embodied in Various omissions, substitutions and changes in the form of methods and systems may depart from the spirit of this disclosure. For example, multiple blocks may be presented in a given sequence, but Alternate embodiments may perform similar functions with different components and / or circuit topologies. Some blocks can be deleted, moved, added, subdivided, combined, and / or modified. Each of these blocks can be implemented in a variety of different ways. Any suitable combination of elements and steps of the various embodiments described above may be used to provide further embodiments. The appended claims and their equivalents are intended to encompass all aspects of the present disclosure. It is intended to cover such forms or modifications as come within the scope and spirit of the present invention.

Claims

1. A tunable filter in which the rejection is tunable, a first inductor; a second inductor mutually coupled to the first inductor; a tunable impedance circuit electrically connected to the first inductor; Including, the tunable impedance circuit includes a switch; The frequency response of the tunable filter is adjusted by changing the state of the switch. configured to adjust at least two notches in the answer; The tunable filter is arranged to filter radio frequency signals. , tunable filters.

2. The switch selectively electrically couples one end of a capacitor to the first inductor.

10. The tunable filter of claim 1, arranged so as to

3. The tunable impedance circuit connects one end of a second capacitor to the first inductor.

3. The tuner of claim 2, further comprising a second switch arranged to selectively electrically couple to said first switch. Filters available.

4. By changing the state of the switch, the frequency of the tunable filter can be adjusted.

10. The tunable filter of claim 1, wherein the positions of at least three notches in the response are adjusted. filter.

5. The tunable impedance circuit includes a tunable capacitance circuit.

10. The tunable filter of claim 1.

6. 6. The method of claim 5, wherein the tunable capacitance circuit is in parallel with the first inductor. Tunable filter.

7. 7. The tunable filter of claim 6, wherein the first inductor is in series with the second inductor. Filter.

8. further comprising a second tunable capacitance circuit in parallel with the second inductor. The tunable filter of claim 7.

9. The tunable capacitance circuit includes the first inductor and the second inductor. and a tube according to claim 5, arranged to provide a shunt capacitance at a node between Filterable.

10. the first inductor is in series with the second inductor; a first capacitance in parallel with the first inductor; 2. The tunable amplifier of claim 1, wherein a second capacitance is in parallel with the second inductor. Performance filter.

11. a shunt capacitor coupled between the first inductor and the second inductor; The tunable filter of claim 10, comprising:

12. The tunable impedance circuit is configured to provide the first capacitance.

12. The tunable filter of claim 11, wherein

13. the first inductor is a series inductor; 2. The tunable filter of claim 1, wherein the second inductor is a shunt inductor. 。

14. The tunable impedance circuit includes a tunable inductor in parallel with the first inductor.

14. The tunable filter of claim 13, comprising a variable capacitance circuit.

15. 15. The tuner of claim 14, including an inductor-capacitor circuit in series with the first inductor. Filters available.

16. the inductor-capacitor circuit includes a third inductor; The third inductor is connected to at least one of the first inductor and the second inductor.

16. The tunable filter of claim 15, wherein the tunable filter is cross-coupled.

17. 10. The tunable filter of claim 1, wherein the at least two notches provide harmonic rejection. Ta.

18. 1. A method for filtering a radio frequency signal, comprising: filtering a first radio frequency signal with a tunable filter in a first state; And, After filtering the first radio frequency signal, the tunable filter changing the state of the switch of the tunable impedance circuit from the first state to the second state; By adjusting the frequency response of the tunable filter, a small amount of the frequency response corresponding to the harmonics of the tunable filter is and adjusting at least two notches, wherein the tunable filters are interconnected. a tunable impedance circuit, a variable impedance circuit electrically connected to the mutually coupled inductors; While the tunable filter is in the second state, the tunable filter filtering the second radio frequency signal by the filter; A method comprising:

19. By changing the state of the switch, the frequency response of the tunable filter is adjusted.

20. The method of claim 18, wherein at least three notches of the answer are adjusted.

20. 1. A wireless communication device, comprising: a first inductor, a second inductor mutually coupled to the first inductor, and a a tuning circuit electrically connected to the inductor; a tunable filter, the tunable impedance circuit including a switch, The frequency domain of the tunable filter is adjusted by changing the state of the switch. a tunable fan configured to adjust at least two notches in the fan; Filter and transmit a radio frequency signal filtered by the tunable filter and an antenna configured as follows:

1. A wireless communication device comprising:

21. 1. A tunable filter with harmonic rejection, comprising: a first inductor; a second inductor mutually coupled to the first inductor; a tunable capacitance circuit electrically connected to the first inductor; Including, The tunable capacitance circuit is at least 2×2 Ｎ For harmonics, To tune the harmonic rejection of the tunable filter, and N switches configured to adjust the effective capacitance of the capacitance circuit. fruit, N is a positive integer greater than 1, The tunable filter is arranged to filter radio frequency signals. , tunable filters.

22. The N switches are at least 3×2 Ｎ The tunable filter for harmonics 22. The tunable filter of claim 21 configured to tune harmonic rejection of the filter. Filter.

23. 3. The method of claim 2, wherein the tunable capacitance circuit is in parallel with the first inductor. 1 tunable filter.

24. a capacitance in parallel with the second inductor; a shunt capacitance between the first inductor and the second inductor; further comprising 24. The tunable amplifier of claim 23, wherein the first inductor is in series with the second inductor. filter.

25. By changing the state of a first switch of the plurality of switches, the tunable 22. The method of claim 21, wherein the position of at least two notches in the frequency response of the active filter is varied. Tunable filter.

26. By changing the state of a first switch of the plurality of switches, the tunable 22. The frequency response of claim 21, wherein the positions of at least three notches in the frequency response of the active filter are varied. Tunable filter.

27. 22. The tunable filter of claim 21, wherein the second inductor is a shunt inductor. Ta.

28. 3. The method of claim 2, wherein the tunable capacitance circuit is in parallel with the first inductor. 7 tunable filters.

29. further comprising a shunt capacitor in series with the second inductor; The shunt capacitor is electrically connected to the first inductor via the second inductor.

30. The tunable filter of claim 28, wherein the tunable filter is connected to

30. The above 2x2 Ｎ The harmonics include at least one second harmonic and at least one third harmonic.

22. The tunable filter of claim 21, comprising:

31. The above 2x2 Ｎ The harmonic is at least one associated with a fifth generation new radio operating band.

22. The tunable filter of claim 21, comprising harmonics of

32. The above 2x2 Ｎ The harmonic is at least one associated with a fifth generation new radio operating band. harmonics of the 4th generation long-term evolution operating band.

22. The tunable filter of claim 21, wherein both include one harmonic.

33. 1. A wireless communication device, comprising: a radio frequency front end including a tunable filter; an antenna in communication with the radio frequency front end; Including, The tunable filter includes a first inductor, a a second inductor electrically connected to the first inductor; and a tunable capacitor electrically connected to the first inductor. a resistive circuit; The tunable capacitance circuit is at least 2×2 Ｎ For harmonics, To tune the harmonic rejection of the tunable filter, and N switches configured to adjust the effective capacitance of the capacitance circuit. fruit, N is a positive integer greater than 1, The tunable filter is arranged to filter radio frequency signals. , wireless communication devices.

34. The antenna receives radio frequency waves filtered by the tunable filter.

34. The wireless communication device of claim 33, arranged to transmit a digital signal.

35. the radio frequency front end includes an antenna switch; The tunable filter is coupled between the antenna switch and the antenna.

34. The wireless communication device of claim 33.

36. the radio frequency front end includes a power amplifier and a band select switch; The tunable filter is coupled between the power amplifier and the band select switch.

34. The wireless communication device of claim 33.

37. the wireless communication device is configured to implement dual connectivity; the tunable filter is configured to provide rejection for the dual connection.

34. The wireless communication device of claim 33.

38. the wireless communication device is configured to implement carrier aggregation; The tunable filter is configured to provide blocking for the carrier aggregation.

34. The wireless communication device of claim 33 configured to:

39. 34. The wireless communication device of claim 33, wherein N is at least four.

40. 1. A radio frequency system comprising: Antenna switch, a first inductor, a second inductor mutually coupled to the first inductor, and a a tuning circuit electrically connected to the inductor; Possible filters, Antenna port and Including, The tunable capacitance circuit is at least 2×2 Ｎ For harmonics, To tune the harmonic rejection of the tunable filter, and N switches configured to adjust the effective capacitance of the capacitance circuit. fruit, N is a positive integer greater than 1, the tunable filter is arranged to filter radio frequency signals; The tunable filter is connected between the antenna switch and the antenna port. A radio frequency system coupled to the signal path.

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