Transformer-based wideband filter with ripple reduction

Abstract

The present disclosure relates to transformer-based wideband filters with reduced ripple. A radio frequency filter circuit includes a first inductor, a second inductor, and a conductive loop. The first inductor receives a first current, the first current inducing a second current in the second inductor when the first current is received. The first inductor and / or the second inductor induces a third current in the conductive loop. The conductive loop adjusts the third current to reduce a first gain peak of an output signal relative to a second gain peak of the output signal.

Description

[0001] Case Separation Statement

[0002] This application is a divisional application of Chinese invention patent application filed on June 8, 2021, entitled "Transformer-based Broadband Filter with Ripple Reduction" and with application number 202110635891.8. Technical Field

[0003] This disclosure relates generally to electronic devices, and more specifically to electronic devices for transmitting and receiving radio frequency signals for wireless communication. Background Technology

[0004] This disclosure relates generally to electronic devices, and more specifically to electronic devices for transmitting and receiving radio frequency signals for wireless communication.

[0005] This section is intended to introduce the reader to various aspects of the art that may be related to the aspects of this disclosure, which are described below and / or protected by the claims. This discussion is intended to help provide the reader with background information to better understand the aspects of this disclosure. Accordingly, it should be understood that these statements should be read in this regard and not as an endorsement of prior art.

[0006] Electronic communication devices may include radio frequency (RF) filtering circuits that allow or block certain frequencies in an output signal to pass through, enabling the signal to be transmitted at a desired frequency. For example, many electronic devices utilize RF filtering circuits that include broadband filters to allow signals to pass through a wide bandwidth (e.g., a large frequency range). RF filtering circuits may include one or more coupled resonators to form one or more filters. A resonator can refer to a device, system, or circuit that exhibits oscillations with relatively large amplitudes at certain frequencies (e.g., resonant frequencies). Resonant circuits include discrete components that act as resonators when both inductors and capacitors are included. In such circuits, oscillations can be limited by resistance via specific resistive components or by including resistance due to the resistance of the inductor windings (e.g., a resistor-inductor-capacitor (RLC) circuit). Summary of the Invention

[0007] The following outlines some of the embodiments disclosed herein. It should be understood that these aspects are presented merely to provide the reader with a concise overview of these particular embodiments, and are not intended to limit the scope of this disclosure. In fact, this disclosure may cover many aspects not set forth below.

[0008] An RF filtering circuit includes a transformer-based resonator that allows or blocks certain frequencies in an output signal (e.g., an outgoing signal) so that the signal can be transmitted at a desired frequency. Alternatively, the transformer-based resonator can provide broadband impedance matching within an amplifier (e.g., over a wide frequency range and within the range of available impedance). By way of example, a transformer-based resonator can be used for input matching, output matching, and / or inter-stage matching within an amplifier. The resonator includes a first inductor (e.g., one or more coils), a second inductor (e.g., one or more coils), and a conductive loop. The conductive loop includes a resistor, which can be a programmable variable resistor or a static resistor.

[0009] When a power source supplies current to the first inductor, the first inductor induces a current in the second inductor via a "transformer effect." Specifically, the current in the first inductor can comprise two components: a first even-mode current and a first odd-mode current. The first even-mode current induces a second even-mode current in the second inductor, and the first odd-mode current induces a second odd-mode current in the second inductor. The first even-mode current and the second even-mode current travel in the same direction through the first and second inductors. Conversely, the first odd-mode current and the second odd-mode current travel in opposite directions through the first and second inductors.

[0010] Since the first odd-mode current flowing through the first inductor and the second odd-mode current flowing through the second inductor have equal magnitudes and flow in opposite directions, the currents cancel each other out relative to the conductive loop, resulting in no current transfer within the conductive loop. Therefore, current cannot travel through the resistor coupled to the conductive loop. Thus, and as described below, the conductive loop with the resistor can affect the frequency response associated with the even-mode current (e.g., gain peak at low frequencies) to reduce in-band ripple, but cannot affect the frequency response associated with the odd-mode current (e.g., gain peak at high frequencies).

[0011] The first and second even-mode currents flowing through the first and second inductors generate induced currents in the conductive loop, which, at least in part due to the resistors, reduce the first gain peak of the output signal (e.g., at the low-frequency pole in the frequency response) to correlate (e.g., approximately match) with the second gain peak of the output signal. This reduces in-band ripple between the gain peaks. As mentioned above, in-band ripple can refer to the frequency response of the resonator's operating region, which includes the first pole, the second pole, and the area between these two poles. Otherwise, a resonator in an RF filter circuit can produce a frequency response with in-band ripple, which can result in poor error vector magnitude (EVM) and / or signal-to-noise ratio (SNR) values ​​when an electronic device including an RF filter circuit is transmitting an output signal. In some embodiments, the resonator may also include one or more shunt resistors and / or one or more series resistors. These resistors can further smooth the in-band ripple by improving the resonator's performance, at least in part, by reducing the peak difference across the frequency response including the first and second peak gains.

[0012] One aspect of this disclosure provides a radio frequency (RF) filter circuit. The RF filter circuit includes a first inductor, a second inductor, and a conductive loop. The first inductor receives a first current, and the second inductor is inductively coupled to the first inductor based on the first current. The first current induces a second current in the second inductor. The conductive loop is inductively coupled to at least one of the first and second inductors, thereby inducing a third current in the conductive loop. The conductive loop modulates the third current to reduce a first gain peak of the output signal relative to a second gain peak of the output signal.

[0013] Another aspect of this disclosure provides an electronic device with a radio frequency (RF) filter circuit. The electronic device includes a current source, a first coil coupled to the current source, a second coil, a conductive loop, and a resistor. The first coil generates a first even-mode current and a first odd-mode current based on current received from the current source. The second coil conducts a second even-mode current induced by the first even-mode current, wherein the first even-mode current flows through the first coil, and the second even-mode current flows through the second coil in the same direction. The second coil conducts a second odd-mode current induced by the first odd-mode current, wherein the odd-mode current flows through the first coil, and the second odd-mode current flows through the second coil in the opposite direction. The conductive loop conducts an induced current, wherein the induced current is induced by the first even-mode current traveling through the first coil and the second even-mode current traveling through the second coil. The resistor is coupled to the conductive loop and adjusts the induced current to reduce a first gain peak of the frequency response of the RF filter circuit relative to a second gain peak of the frequency response.

[0014] Another aspect of this disclosure provides a transformer-based resonator. The transformer-based resonator includes a first inductor, a second inductor, a third inductor, and a variable resistor. When current is supplied to the first inductor, the first inductor transmits a first even-mode current and a first odd-mode current. The second inductor transmits a second even-mode current induced by the first even-mode current and traveling in the same direction as the first even-mode current, and transmits a second odd-mode current induced by the first odd-mode current and traveling in the opposite direction to the first odd-mode current. The third inductor transmits an induced current, which is induced by the first even-mode current traveling through the first inductor and the second even-mode current traveling through the second inductor. The variable resistor adjusts the coupling factor between the first and second inductors to reduce the in-band ripple between a first gain peak and a second gain peak in the frequency response of the transformer-based resonator.

[0015] Various modifications to the above-described features may exist with respect to various aspects of the invention. Other features may also be incorporated into these aspects. These modifications and additional features may exist individually or in any combination. For example, various features discussed below relating to one or more illustrated embodiments may be incorporated individually or in any combination into any of the above aspects of the invention. The brief summary presented above is intended only to familiarize the reader with specific aspects and context of the embodiments disclosed herein and does not limit the claimed subject matter. Attached Figure Description

[0016] A better understanding of the various aspects of this disclosure can be achieved by reading the following detailed description and referring to the accompanying drawings, in which:

[0017] Figure 1 This is a block diagram of an electronic device according to an embodiment of the present disclosure;

[0018] Figure 2 It means Figure 1 A perspective view of a laptop computer representing an implementation scheme for an electronic device;

[0019] Figure 3 It represents Figure 1 A front view of a handheld device, representing another embodiment of an electronic device;

[0020] Figure 4 It means Figure 1 A front view of another handheld device in another embodiment of an electronic device;

[0021] Figure 5 It means Figure 1 A front view of a desktop computer in another embodiment of an electronic device;

[0022] Figure 6 It means Figure 1 A front view and a side view of another embodiment of a wearable electronic device;

[0023] Figure 7 This is a circuit diagram of a transformer-based coupled resonator for an RF filter circuit;

[0024] Figure 8 It is implemented on a silicon chip. Figure 7 A schematic diagram of a resonator;

[0025] Figure 9A It has series resistors and shunt resistors. Figure 7 Circuit diagram of the resonator;

[0026] Figure 9B yes Figure 9A The circuit diagram of the resonator shows the even-mode current flowing through the resonator;

[0027] Figure 9C It is shown Figure 9A The circuit diagram of the resonator shows the odd-mode current flowing through the resonator;

[0028] Figure 10 This is an example Figure 9A A graph showing the frequency poles of the frequency response of a resonator;

[0029] Figure 11A The embodiments shown in this disclosure have the effect of reducing Figure 7 The circuit diagram of the resonator with frequency response and in-band ripple in the conductive loop.

[0030] Figure 11B The embodiments shown in this disclosure are those with even-mode currents. Figure 11A Circuit diagram of the resonator;

[0031] Figure 11C The embodiments shown in this disclosure are those with odd-mode currents. Figure 11A Circuit diagram of the resonator;

[0032] Figure 12 It is based on the implementation scheme of this disclosure. Figure 11A A schematic diagram of a resonator;

[0033] Figure 13A It is based on the implementation scheme of this disclosure. Figure 11A A schematic diagram of the cross-sectional view of the resonator;

[0034] Figure 13B It is based on the implementation scheme of this disclosure. Figure 11A A schematic diagram of the perspective view of the resonator; and

[0035] Figure 14 This is an example of an implementation scheme disclosed herein. Figure 11B The frequency poles of the frequency response of the output signal in the operating region of the resonator are plotted. Detailed Implementation

[0036] One or more specific implementations will be described below. To provide a brief description of these implementations, not all characteristics of the actual implementations are described in this specification. It should be understood that in the development of any such actual implementation, as in any engineering or design project, decisions must be made specific to many implementations to achieve the developer's specific objectives, such as compliance with system-related and business-related constraints that may vary from one implementation to another. Furthermore, it should be understood that such development work can be complex and time-consuming, but will still be routine work of design, fabrication, and manufacturing for those skilled in the art who benefit from this disclosure.

[0037] When describing elements of various embodiments of this disclosure, the articles “an” and “the” are intended to refer to the presence of one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be included and to indicate the presence of additional elements besides those listed. Additionally, it should be understood that reference to “an embodiment” or “an embodiment” of this disclosure is not intended to be construed as excluding the existence of additional embodiments also incorporating the cited features. The use of the terms “approximately” or “close to” should be understood to mean including close to the target (e.g., design, value, quantity), such as within limits of any suitable or conceivable error (e.g., within 0.1% of the target, within 1% of the target, within 5% of the target, within 10% of the target, within 25% of the target, etc.).

[0038] As used herein, the term "frequency response" refers to the gain of an output signal as a function of frequencies within a frequency range (e.g., the operating region of a resonator filter). Additionally, as used herein, the term "frequency pole" refers to a frequency at which the transfer function of a system approaches high gain or amplitude (e.g., infinity). By way of example, a frequency pole may include the highest gain or amplitude of the frequency response of a resonator filter, or a specific frequency with relatively high gain or amplitude (e.g., high-frequency pole and low-frequency pole). As used herein, the terms "peak," "peak gain," or "gain peak" refer to the highest gain or amplitude at a frequency pole, or a relatively high gain or amplitude (e.g., a gain peak at a high-frequency pole). This relatively high gain at a particular frequency produces a peak relative to the relatively low gain at other frequencies of the frequency response. Furthermore, as used herein, the term "non-uniform gain" refers to the difference between two or more gain peaks (e.g., the gain difference between a gain peak at a low-frequency pole and a gain peak at a high-frequency pole). As used herein, the term "in-band ripple" refers to the ripple or variation in the frequency response of a resonator filter encompassing the first pole, the second pole, and the operating region between these two poles. The ripple includes the difference or disparity in gain peaks between the gain peaks at the frequency poles, with a gain drop between these two gain peaks.

[0039] Radio frequency (RF) filter circuits may include transformer-based resonators, which may include multiple inductors, such as a primary inductor (e.g., a first inductor) and a secondary inductor (e.g., a second inductor). If the primary inductor receives current, such as from a current source, it can transfer the current to the second inductor, thus inducing a current in the secondary inductor. Specifically, the current in the primary inductor can change as it flows through the inductor's coil, generating a changing magnetic field (e.g., magnetic flux) that induces the current in the secondary inductor. This transfer of current or electrical energy from one inductor to another due to the changing magnetic field is known as the "transformer effect."

[0040] In some cases, some current from the primary inductor may not be transferred to the secondary inductor. Instead, this current may not follow the expected path through the coil of the primary inductor. This portion of the current can be referred to as leakage flux. The extent of the transfer can be measured by various parameters, including the coupling coefficient k. The coupling coefficient can be adjusted or tuned, for example, by circuit elements (e.g., resistors or capacitors coupled to the first and / or second inductors), to change filter parameters and bandwidth. However, adjusting the coupling coefficient alone may not provide a tuning effect that reduces the non-uniform gain of the output signal (e.g., the in-band signal) at different frequency poles (e.g., low-frequency poles and high-frequency poles), resulting in persistently unintended and / or undesirable filter performance. Therefore, electronic devices with RF filtering circuitry can benefit from circuitry that provides the same or substantially the same gain (e.g., similar and within the gain threshold) of the output signal at different frequency poles.

[0041] The embodiments disclosed herein can be applied to a variety of electronic devices with radio frequency (RF) filtering circuitry. Specifically, any electronic device transmitting signals over a communication network can incorporate the RF filtering circuitry disclosed herein to ensure signal transmission with similar gain over a target frequency range, excluding the expected gain applied to the signal at a specific frequency. In light of the foregoing, a general description of suitable electronic devices that may include the disclosed RF filtering circuitry is provided below.

[0042] Considering the foregoing, there are various suitable communication devices that may include the radio frequency filtering circuit disclosed herein. First, let's turn to... Figure 1 The electronic device 10 according to the embodiments of the present disclosure may, among other things, include one or more processors 12, memory 14, non-volatile storage device 16, display 18, input structure 22, input / output (I / O) interface 24, network interface 26, power supply 28, and transceiver 30. Figure 1 The various functional blocks shown may include hardware elements (including circuits), software elements (including computer code stored on a computer-readable medium), or a combination of both hardware and software elements. It should be noted that... Figure 1 This is merely one example of a specific implementation and is intended to illustrate the types of components that may exist in electronic device 10.

[0043] For example, electronic device 10 can represent Figure 2 The laptop shown Figure 3 The handheld device shown Figure 4 The handheld device shown Figure 5 The desktop computer shown Figure 6 The diagram shows a wearable electronic device or similar device. It should be noted that... Figure 1The processor 12 and other related items herein may be generally referred to as "data processing circuitry". This data processing circuitry may be implemented wholly or partially as software, hardware, or any combination thereof. Furthermore, the processor 12 and... Figure 1 Other related items may be a single, independent processing module, or may be fully or partially integrated into any of the other components within the electronic device 10.

[0044] exist Figure 1 In the electronic device 10, processor 12 may be operatively coupled to memory 14 and non-volatile storage device 16 to execute various algorithms. Such programs or instructions executed by processor 12 may be stored in any suitable article of writing comprising one or more tangible computer-readable media. The tangible computer-readable media may include memory 14 and / or non-volatile storage device 16, individually or jointly, to store instructions or routines. Memory 14 and non-volatile storage device 16 may include any suitable article of writing for storing data and executable instructions, such as random access memory, read-only memory, rewritable flash memory, hard disk drive, and optical disk. Furthermore, programs (e.g., operating systems) encoded on such computer program products may also include instructions executable by processor 12 to enable electronic device 10 to provide various functions.

[0045] In some embodiments, display 18 may be a liquid crystal display (LCD) that facilitates viewing images generated on electronic device 10 by a user. In some embodiments, display 18 may include a touchscreen that facilitates interaction between a user and the user interface of electronic device 10. Furthermore, it should be understood that in some embodiments, display 18 may include one or more light-emitting diode (LED) displays, organic light-emitting diode (OLED) displays, active-matrix organic light-emitting diode (AMOLED) displays, or some combination of these and / or other display technologies.

[0046] The input structure 22 of electronic device 10 allows a user to interact with electronic device 10 (e.g., pressing a button to increase or decrease the volume level). Like network interface 26, I / O interface 24 enables electronic device 10 to interact with various other electronic devices. Network interface 26 may include, for example, one or more interfaces for personal area networks (PANs) such as... Networks, local area networks (LANs), or wireless local area networks (WLANs) such as 802.11x Networks, and / or wide area networks (WANs) such as 3rd generation (3G) cellular networks, Universal Mobile Telecommunications System (UMTS), 4th generation (4G) cellular networks, Long Term Evolution (LTE) Cellular networks, Long Term Evolution License Assisted Access (LTE-LAA) cellular networks, 5G cellular networks, and / or New Radio (NR) cellular networks. Specifically, network interface 26 may include, for example, one or more interfaces for using Release-15 cellular communication standards that include millimeter wave (mmWave) frequency ranges (e.g., 24.25–300 GHz). The transceiver 30 of the electronic device 10, including a transmitter and receiver, may allow communication over the aforementioned networks (e.g., 5G, Wi-Fi, LTE-LAA, etc.).

[0047] Network interface 26 may also include one or more interfaces for, for example, a broadband fixed wireless access network (e.g., Mobile broadband wireless network (mobile) Asynchronous digital subscriber lines (e.g., ADSL, VDSL) and digital video terrestrial broadcasting Network and its extensions DVB handheld Networks, ultra-wideband (UWB) networks, AC power lines, etc.

[0048] In some implementations, electronic device 10 uses transceiver 30 via the aforementioned wireless network (e.g., move 4G The transceiver 30 may include circuitry available for both wireless receiving and wireless transmitting of signals (e.g., data signals, wireless data signals, wireless carrier signals, RF signals), such as a transmitter and / or receiver. In fact, in some embodiments, the transceiver 30 may include a transmitter and receiver combined into a single unit, or in other embodiments, the transceiver 30 may include a transmitter separate from the receiver. The transceiver 30 can transmit and receive RF signals to support wireless applications such as, for example, PAN networks (e.g., 5G, etc.). ), WLAN networks (e.g., 802.11x) ), WAN networks (e.g., 3G, 4G, 5G, NR and (and LTE-LAA cellular network) Network, Mobile Network, ADSL and VDSL networks, and Voice and / or data communication in networks, UWB networks, etc. As further shown, electronic device 10 may include power supply 28. Power supply 28 may include any suitable power source, such as a rechargeable lithium polymer (Li-poly) battery and / or an alternating current (AC) power converter.

[0049] In some embodiments, electronic device 10 may take the form of a computer, portable electronic device, wearable electronic device, or other type of electronic device. Such a computer may be a typically portable computer (such as a laptop, notebook computer, and tablet computer) or a computer typically used in one location (such as a conventional desktop computer, workstation, and / or server). In some embodiments, electronic device 10 in the form of a computer may be a product purchased from Apple Inc., Cupertino, California. Pro, MacBook mini or Mac Model. By way of example, according to one embodiment of this disclosure, in... Figure 2 An electronic device 10 in the form of a laptop computer 10A is shown. The laptop computer 10A shown may include a casing or housing 36, a display 18, input structures 22, and ports for I / O interfaces 24. In one embodiment, the input structures 22 (such as a keyboard and / or touchpad) can be used to interact with the computer 10A, such as to launch, control, or operate a graphical user interface (GUI) or applications running on the computer 10A. For example, the keyboard and / or touchpad can allow a user to navigate on the user interface and / or application interface displayed on the display 18.

[0050] Figure 3 A front view of a handheld device 10B is depicted, representing one embodiment of an electronic device 10. The handheld device 10B can represent, for example, a portable telephone, media player, personal data manager, handheld gaming platform, or any combination of such devices. For instance, the handheld device 10B could be purchased from Apple Inc. (Cupertino, California). or Handheld device 10B may include a housing 36 to protect internal components from physical damage and / or shield them from electromagnetic interference. The housing 36 may enclose the display 18. I / O interface 24 can be opened through the housing 36 and may include, for example, I / O ports for hardwired connections to allow charging and / or content manipulation using standard connectors and protocols such as the Lightning connector supplied by Apple Inc. of Cupertino, California, Universal Serial Bus (USB), or other similar connectors and protocols.

[0051] Input structure 22, in conjunction with display 18, allows the user to control handheld device 10B. For example, input structure 22 can activate or deactivate handheld device 10B, navigate the user interface to a home screen, a user-configurable application screen, and / or activate voice recognition features of handheld device 10B. Other input structures 22 may provide volume control or switch between vibration and ringtone modes. Input structure 22 may also include a microphone for acquiring user voice for various voice-related features, and a speaker for enabling audio playback and / or certain telephone functions. Input structure 22 may also include a headphone input for connecting to external speakers and / or headphones.

[0052] Figure 4 A front view of another handheld device 10C is depicted, representing another embodiment of electronic device 10. The handheld device 10C can represent, for example, a tablet computer, or one of various portable computing devices. For instance, the handheld device 10C can be a tablet-sized embodiment of electronic device 10, specifically, for example, a device purchased from Apple Inc. (Cupertino, California). Type of handheld device.

[0053] See Figure 5 Computer 10D can represent Figure 1 Another embodiment of the electronic device 10. The computer 10D can be any computer, such as a desktop computer, server, or laptop, but can also be a standalone media player or video game console. For example, the computer 10D could be a device from Apple Inc. in Cupertino, California. Or another similar device. It should be noted that computer 10D may also refer to a personal computer (PC) from another manufacturer. A similar housing 36 may be provided to protect and enclose the internal components of computer 10D, such as monitor 18. In some embodiments, the user of computer 10D may interact with computer 10D using various peripheral input structures 22 that can be connected to computer 10D, such as keyboard 22A or mouse 22B (e.g., input structure 22).

[0054] Similarly, Figure 6 Depicting the representation Figure 1 Another embodiment of the electronic device 10 is a wearable electronic device 10E, which can be configured to operate using the techniques described herein. By way of example, the wearable electronic device 10E, which may include a wristband 43, could be an Apple product of Apple, Inc., Cupertino, California. However, in other embodiments, the wearable electronic device 10E may include any wearable electronic device, such as, for example, a wearable motion monitoring device (e.g., a pedometer, accelerometer, heart rate monitor), or other devices from another manufacturer. The display 18 of the wearable electronic device 10E may include a touchscreen display 18 (e.g., an LCD, LED display, OLED display, active-matrix organic light-emitting diode (AMOLED) display, etc.) and an output structure 22 that allows the user to interact with the user interface of the wearable electronic device 10E.

[0055] Considering the above, Figure 7 This is a schematic diagram of a transformer-based coupled resonator 50 for an RF filter circuit. Generally, a resonant circuit may include a first inductor and a second inductor. These inductors can form a transformer when placed too close together and current flows between them. That is, when current is received through the first inductor, the current in the first inductor can induce or transfer electrical energy (e.g., magnetic flux) from the first inductor to the second inductor. Each inductor in the resonant circuit coupled with a capacitor can be referred to as a magnetically coupled resonator, where energy oscillates between the coil of the inductor (e.g., the transformer) and a capacitor that stores energy at a specific resonant frequency in an electric field. The offset between the first and second inductors is often used to tune parameters of the transformer, such as the coupling coefficient k. In some cases, capacitors and / or resistors in the resonant circuit can be used to tune the coupling coefficient. Tuning allows for changes in the filter's bandwidth (e.g., a wider or narrower frequency range) and / or in-band ripple caused by non-uniform peak gain at multiple frequency poles. However, adjusting the coupling coefficient can lead to non-uniform gain of the output signal at multiple frequency poles, which can result in undesirable filter performance.

[0056] As depicted in the embodiment, the transformer-based coupled resonator 50 has a first inductor 52 (L1), a second inductor 54 (L2), a first capacitor 56 (C1), and a second capacitor 58 (C2). The first inductor 52 is coupled to the first capacitor 56, and the second inductor 54 is coupled to the second capacitor 58. Each of these inductor-capacitor (LC) arrangements can serve as an LC resonant circuit that stores energy oscillating at the resonant frequency of the circuit. The LC circuit can generate a signal at a specific frequency or pass a signal at a specific frequency (e.g., a bandpass filter).

[0057] Generally, resonator 50 may include coupling elements that facilitate broadband filtering. Coupling elements may include components that allow energy to be coupled or transferred from one inductive circuit segment of resonator 50 (e.g., one or more coils of the first inductor 52) to another inductive circuit segment (e.g., another one or more coils of the second inductor 54). Coupling elements may be capacitive and / or magnetic. Capacitive coupling elements can provide energy transfer between circuit segments due to changes in the electric field caused by voltage. Magnetic coupling elements can provide energy transfer due to changes in the magnetic field caused by current.

[0058] As shown in the figure, resonator 50 includes capacitors on each inductor side, such as a first capacitor 56 coupled to the first inductor 52 and a second capacitor 58 coupled to the second inductor 54. When current is applied to resonator 50, these coupling elements can form a magnetically coupled resonator. (As shown in the figure, the resonator 50 includes capacitors on each inductor side, such as a first capacitor 56 coupled to the first inductor 52 and a second capacitor 58 coupled to the second inductor 54.) Figures 9A to 9C As discussed in detail, adjusting the coupling coefficient of resonator 50 allows for adjustment of the filter bandwidth and / or the in-band ripple of the frequency response of the output signal through resonator 50.

[0059] Figure 8 A resonator 50 implemented on a silicon chip is shown. As shown, the resonator 50 can be formed using a first inductor 52 (indicated by a bright spot pattern) and a second inductor 54 (indicated by a dark spot pattern) arranged in a multilayer stack architecture on a printed circuit board 55 (PCB). While the following discussion describes a resonator 50 implemented on a PCB representing a particular embodiment, the resonator 50 can, conversely, be implemented on a silicon chip or integrated circuit. The first inductor 52 and / or the second inductor 54 can be disposed, for example, by mounting on and / or etching into a first (e.g., lower) layer of the PCB 55. Here, the first inductor 52 is disposed (e.g., positioned) on a first layer of the PCB 55, while the second inductor 54 is disposed on a second (e.g., higher or lower) layer of the PCB 55. In some embodiments, a portion of the coil of the first inductor 52 may be disposed on the first layer, while another portion of the coil of the first inductor 52 may be disposed on the second layer. In such embodiments, these portions may be coupled using vias 53, allowing current flowing (e.g., traveling) through the first inductor 52 to flow between the two layers without obstruction. Similarly, the second inductor 54 may also include a portion of its coil disposed on the second layer, while another portion of its coil is disposed on another layer (e.g., a third layer higher than the second layer). The second inductor may also include vias 53 to couple these portions together. In some embodiments, circuit segments or components of the resonator 50 may be spaced apart on separate PCBs. That is, the first inductor 52 may be positioned on the first PCB, while the second inductor 54 may be positioned on a second PCB coupled to the first PCB.

[0060] In embodiments with even-mode currents, and as referenced Figure 9B As discussed in detail, when current 70(I) is applied to the first inductor 52 in the depicted stacked architecture of resonator 50, the current can flow through the first inductor 52 in the direction indicated by the solid arrow. Specifically, the direction indicated by the arrow illustrates the flow of current 70 through the coil of the first inductor 52 in the first direction. Upon receiving current 70, the first inductor 52 can induce (e.g., generate, conduct, or transmit) current 71 in the second inductor 54, which flows through the second inductor 54 in the same direction. In embodiments with odd-mode currents, and as referenced... Figure 9C As discussed in detail, when current 70 is applied to the first inductor 52, current 70 can flow through the first inductor 52 in a first direction and induce current 71 in the second inductor 54. Specifically, the direction indicated by the dashed arrow illustrates that when current 70 is received, the first inductor 52 can induce current 71 in the second inductor 54, which flows through the second inductor 54 in a second direction opposite to the first direction. Although the following description depicts current 70 flowing through the first inductor 52 in the first direction (which represents a particular embodiment), current 70 can flow in a different or opposite direction (e.g., a second direction).

[0061] As a result of the transformer effect, the first inductor 52 can induce a current in the second inductor 54. Although not shown, the induced current through the second inductor 54 can flow similarly to the flow in the first inductor 52. Specifically, and as will be noted... Figure 9B and Figure 9C As described in detail, when the current 70 is an even-mode current, the induced current can flow through the second inductor 54 in the same direction, or when the current 70 is an odd-mode current, the induced current can flow through the second inductor 54 in the opposite direction.

[0062] Furthermore, and as previously mentioned, the amplification or gain of the output signal (e.g., the transmitted signal) at various frequencies and / or frequency poles can vary. Specifically, the frequency response of the output signal through resonator 50 can indicate that the gain of the output signal at these various frequencies and / or frequency poles can be different (e.g., relatively high gain at low-frequency poles and relatively low gain at high-frequency poles), resulting in uneven gain peaks at the corresponding frequency poles, thus producing an "in-band ripple effect." The resonator 50 of the RF filter circuit can cause in-band ripple in the frequency response, which can lead to poor EVM and SNR values ​​when the electronic device 10 transmits the output signal.

[0063] To improve filtering performance, adjusting individual filter parameters allows for adjustment of the output signal gain at specific frequencies and / or frequency poles (e.g., increasing or decreasing the gain). By adjusting the gain, the overall frequency response can become more uniform and smooth, thereby removing in-band ripple. To illustrate the components of a tunable filter parameter, Figure 9A A resonator 50 with a capacitor, a resistor, a series resistor and a shunt resistor is depicted.

[0064] like Figure 9A As shown, the resonator 50 may include a first inductor 52 (L1), a second inductor 54 (L2), a first capacitor 56 (C1), and a second capacitor 58 (C2). Here, the first capacitor 58 (C1) may be connected in parallel with the first resistor 57 (R1) and the first shunt resistor 60 (R3), while the second capacitor 58 may be connected in parallel with the second resistor 59 (R2) and the second shunt resistor 62 (R4). Furthermore, a first series resistor 64 (R5) may be connected in series with the first inductor 52 and the first capacitor 56. Similarly, a second series resistor 66 (R6) may be connected in series with the second inductor 54 and the second capacitor 58. While the depicted embodiments exemplify and describe a resonator 50 having both shunt resistors 60, 62 and series resistors 64, 66 for tuning radio frequency filter circuitry, the resonator 50 can be implemented without at least some of these resistors, such as without shunt resistors 60, 62 and / or without series resistors 64, 66. In some embodiments, each RLC circuit of the resonator 50, such as a first RLC circuit 73A including a first inductor 52, a first capacitor 56 and a first resistor 57, and a second RLC circuit 73B including a second inductor 54, a second capacitor 58 and a second resistor 59, can be implemented independently without shunt resistors 60, 62 and / or without series resistors 64, 66.

[0065] For reference Figure 10 The operation of the resonator 50 in the RF filter circuit is discussed in detail via shunt resistors 60, 62 and / or series resistors 64, 66. In addition to adjusting the operation of the resonator 50 via shunt resistors 60, 62 and / or series resistors 64, 66, or as an alternative, the operation of the resonator 50 is adjusted via first resistor 57, second resistor 59 and / or capacitors 56, 58. Specifically, and as will be described herein, the network quality factor (Q factor) and / or coupling coefficient can be adjusted by tuning filter parameters via first resistor 57, second resistor 59, shunt resistors 60, 62, series resistors 64, 66 and / or capacitors 56, 58. The Q factor includes the source / load impedance (R1). As will be relative to... Figures 11A to 11CAs discussed in detail, the Q factor can be finite and is associated with the coupling coefficient. Adjusting the coupling coefficient using only the first resistor 57 and the second resistor 59, shunt resistors 60, 62, series resistors 64, 66 and / or capacitors 56, 58 may not effectively reduce or remove in-band ripple in the frequency response of the output signal through the resonator 50.

[0066] As shown, a power source can supply current 70 or voltage (e.g., an input signal) to resonator 50. In the depicted embodiment, the power source provides current 70 to the first inductor 52. A portion of the current 70 is transferred to the second inductor 54 via a transformer effect, thereby inducing current in the second inductor 54 as previously described. As current 70 is transferred from the first inductor 52 to the second inductor 54, the current 70 can flow through the coil of the second inductor 54 in the same or opposite direction relative to the current 70 flowing through the coil of the first inductor 52.

[0067] For example, Figure 9B A resonator 50 with even-mode current is shown. A total current 70 supplied to the resonator 50 flows through a first inductor 52 and may comprise two parts: an even-mode current and an odd-mode current. As shown, the total current 70 through the first inductor 52 is divided into a first even-mode current 72A(i / 2) and a first odd-mode current 74A(i / 2), each having half the magnitude of the total current 70. The first even-mode current 72A results in a second even-mode current 72B in the second inductor 54, which has half the magnitude and flows in the same direction as the first even-mode current 72A through the first inductor 52 (e.g., as indicated by the current arrows pointing in the same direction). That is, current can flow through the coil of the first inductor 52 in a specific direction, and when the current is transferred to the second inductor 54, the current can also flow through the coil of the second inductor 54 in the same direction.

[0068] The polarity point 75, located adjacent to the coil, indicates the polarity associated with the respective inductors 52 and 54. The direction of the current 70 can be determined or indexed relative to the polarity point 75. A first even-mode current 72A can flow into the polarity point 75 for the first inductor 52 (e.g., primary current through the primary side of a transformer), and a second even-mode current 72B can also flow into the polarity point 75 for the second inductor 54 (e.g., secondary current through the secondary side of a transformer). Alternatively, the first even-mode current 72A can flow through the first inductor 52 and out of the polarity point 75, and the second even-mode current 72B can flow through the second inductor 54 and out of the polarity point 75. In both cases, the first even-mode current 72A and the second even-mode current 72B flow in the same direction through their respective inductors 52 and 54.

[0069] In the depicted embodiment, the even-mode current 72A through the first inductor 52 causes an even-mode current 72B to flow through the second inductor 54. As previously described, the even-mode currents 72A and 72B flow in the same direction (both flowing toward or out of the polarity point 75). Since both the first even-mode current 72A and the second even-mode current 72B flow in the same direction, the second even-mode current 72B can provide positive feedback to the first even-mode current 72A (e.g., adding an equal and proportional signal in the same direction), resulting in a high gain of the output signal. This amplification can lead to larger oscillations between the gain peak associated with the even-mode current and the gain peak associated with the odd-mode current, resulting in a larger in-band ripple effect.

[0070] When current is transferred from the first inductor 52 to the second inductor 54 through a transformer effect, odd-mode currents can flow in opposite directions (at least in part based on the polarities of inductors 52 and 54). Specifically, a first odd-mode current 74A can flow into polarity point 75 with respect to the first inductor 52, and a second odd-mode current 74B can flow through the second inductor 52 and out of polarity point 75, and vice versa. That is, the first odd-mode current 74A and the second odd-mode current 74B flow through the first inductor 52 and the second inductor 54 in opposite or different directions with respect to polarity point 75. For illustration, Figure 9C A resonator 50 with odd-mode currents is depicted. As shown, a first odd-mode current 74A(i / 2) of the total current 70 supplied to the resonator 50 flows in a specific direction through the first inductor 52, and a second odd-mode current 74B(i / 2) flows in the same direction through the second inductor 54 (e.g., as indicated by current arrows pointing in opposite directions). Specifically, the first odd-mode current 74A results in a second odd-mode current 74B in the second inductor 54, which has half the magnitude and flows in the opposite direction to the first odd-mode current 74A. By way of example, current can flow through the coil of the first inductor 52 in a specific direction, and when the current is transferred to the second inductor 54, the current can be induced to flow in the opposite direction.

[0071] Even-mode and odd-mode analyses can be performed on resonator 50 to determine tuning parameters. Although the following discussion and equations describe a symmetrical transformer-based resonator such that the characteristics of the capacitors, inductors, and / or resistors of the first RLC circuit 73A are related to the characteristics of the capacitors, inductors, and / or resistors of the second RLC circuit 73B (e.g., C1 = C2, L1 = L2, R1 = R2), this represents a particular embodiment. However, the capacitors, inductors, and / or resistors on either side may, conversely, have different or varying characteristics between the first RLC circuit 73A and the second RLC circuit 73B (e.g., C1 ≠ C2, L1 ≠ L2, R1 ≠ R2). That is, Figures 9A to 9C and Figures 11A to 11C The formulas and circuit descriptions do not necessarily have to correspond to those representing a specific implementation. Figures 9A to 9C and Figures 11A to 11C The circuit depicted is consistent. Here, the even-mode and odd-mode voltages of the first RLC circuit 73A of the resonator 50, including the first inductor 52, the first capacitor 56, and the first resistor 57, can be described using the following equations:

[0072]

[0073]

[0074] In these equations, V1 corresponds to the input voltage (e.g., the input signal) and V2 corresponds to the output voltage (e.g., the output signal). By way of example, V1, even corresponds to the even-mode input voltage of the first segment, and V2, even corresponds to the even-mode output voltage of the second RLC circuit 73B of the resonator 50, which includes the second inductor 54, the second capacitor 58, and the second resistor 59. As previously described, i / 2 corresponds to the first even-mode current 72A, R1 corresponds to the first resistor 57 (e.g., a real resistor), and C1 corresponds to the first capacitor 56. w corresponds to the frequency, j corresponds to the imaginary unit (e.g., an imaginary resistor, such as the reactance of an inductor or capacitor), and k corresponds to the coupling factor or coefficient. Although the equations described herein are relative to the first RLC circuit 73A of the resonator 50, these equations may also be applied to the corresponding parameters of the second RLC circuit 73B of the resonator 50 circuit.

[0075] By adding even-mode and odd-mode voltages, the input and output voltages can be expressed as:

[0076]

[0077]

[0078] Equations 3 and 4 can be used to determine one or more frequency poles, or one or more gain peaks of the output signal at one or more specific frequencies. Although the following description refers to two frequency poles of the frequency response, such as low-frequency poles and high-frequency poles, the systems, methods, and equations described herein can be used to determine any suitable number of frequency poles (e.g., one, two, four, seven, etc.). As previously stated, a “pole” can refer to a “gain peak,” such as the highest relative gain of the output signal at other frequencies (e.g., the frequency response). These two poles correspond to a first frequency w1 and a second frequency w2, which can be defined as follows:

[0079]

[0080]

[0081] Furthermore, the network quality factor Q can be defined as:

[0082] Q = R1 * C1 * w0 (Equation 7)

[0083] Where w0 corresponds to the geometric mean frequency, which is defined as:

[0084]

[0085] As mentioned earlier, the coupling factor k indicates the ratio or measurement of inductive coupling between the coils of two inductors. The coupling factor is expressed as a value between 0 and 1, where 0 indicates no inductive coupling and 1 indicates ideal inductive coupling (e.g., no flux leakage). For example, when the coupling factor is 0.5 or greater, the two coils are well coupled. When the coupling factor is less than 0.5, the two coils may not be well coupled (e.g., more flux or current leakage than expected).

[0086] The peak gain of the output signal can vary at a specific frequency (e.g., a first frequency pole) and another specific frequency (e.g., a second frequency pole), allowing the frequency response of resonator 50 to exhibit in-band ripple between the peak gain values. The following equation describes the ideal filter criterion for flattening or smoothing the ripple to a maximum flat response:

[0087] kQ = 1 (Equation 9)

[0088] In other words, to reduce or minimize in-band ripple, the product of the Q factor and the coupling coefficient should be 1 or approximately 1. The product of the Q factor and / or coupling coefficient can be adjusted by changing the values ​​of resistors (e.g., first resistor 57) and / or capacitors (e.g., first capacitor 56). In some cases, adjusting the Q factor can be performed primarily by adjusting the resistors, since the resonant frequency of resonator 50 can vary with the adjustment of the capacitors. For example, if the coupling coefficient is 0.5, resulting in good coupling between the coils of first inductor 52 and second inductor 54, the Q factor can be adjusted to 2 to generate a maximum flat response (e.g., effectively reducing or minimizing in-band ripple). Similarly, when the coupling coefficient is 0.5 and the Q factor is greater than 2, the difference between the gain peaks of the in-band ripple can increase. On the other hand, when the Q factor is less than 2, the two-pole frequency response can degenerate into a single-pole frequency response, and thus lose its bandwidth extension (e.g., broadband filter) benefits.

[0089] As mentioned above, Figures 9A to 9CThe shunt resistors 60, 62 and / or series resistors 64, 66 can also adjust the filter parameters of the resonator 50 (e.g., network Q-factor (Q) and / or coupling coefficient (k)). Specifically, the resonator 50 with shunt resistors 60, 62 and / or series resistors 64, 66 can reduce the peak gain of the output signal at these two frequency poles (e.g., reduce the gain), thereby homogenizing the in-band ripple.

[0090] For example, a first frequency pole at a relatively low frequency can correspond to an even-mode current, and a second frequency pole at a relatively high frequency can correspond to an odd-mode current. The frequency pole at the low frequency corresponds to the even-mode current. Specifically, the gain peak at the low-frequency pole can be relatively higher than the gain peak at the high-frequency pole. As mentioned earlier, since the first even-mode current 72A and the second even-mode current 72B flow in the same direction, the second even-mode current 72B can provide positive feedback to the first even-mode current 72A, resulting in a high gain in the output signal; the relatively high gain peak corresponds to the frequency pole at the lower frequency. On the other hand, since the first odd-mode current 74A and the second odd-mode current 74B flow in opposite directions, resulting in a relatively low gain in the output signal, the relatively low gain peak corresponds to the frequency pole at the higher frequency.

[0091] For example, Figure 10 A graph 100 depicts the gain peaks (e.g., dual-pole frequency response) of the output signal at a first frequency pole 110 and a second frequency pole 112. The first curve 102 illustrates the output signal without a shunt resistor or series resistor (e.g., Figures 9A to 9CThe frequency response of the output signal of the resonator 50 (RLC circuits 73A, 73B) is shown in Figure 100. Furthermore, a second curve 104 illustrates the frequency response of the resonator 50 with one or more series resistors (such as a first series resistor 64 and a second series resistor 66). Additionally, a third curve 106 illustrates the frequency response of the resonator 50 with one or more shunt resistors (such as a first shunt resistor 60 and a second shunt resistor 62). Figure 100 illustrates the output signal over a frequency range 108 in Hertz (Hz) (x-axis) and a corresponding gain 109 in Decibels (dB) (y-axis), thus indicating the frequency response of the output signal of the resonator 50 through the RF filter circuit. Gain 109 indicates the reflection and / or transmission characteristics of the output signal in the frequency domain. Gain 109 can be proportional to the gain of the output signal at a specific frequency, such that the gain value increases as the gain of the output signal increases (e.g., from -8dB to 2dB). That is, a high gain peak can be associated with a high gain value (e.g., approximately -2dB). A low gain value (e.g., approximately -8dB) can correspond to more reflections or losses in the output signal. Therefore, maintaining high gain at various frequencies and / or frequency poles can be advantageous for transmitting the output signal at the desired power level.

[0092] As shown in the first curve 102, the gain peaks at the first frequency pole 110 and the second frequency pole 112 have different gain values, thus generating in-band ripple between the gain peaks at the corresponding frequency poles 110 and 112. To smooth the ripple, the resonator 50 may be implemented with series resistors 64 and 66. As shown in the second curve 104, adding series resistors 64 and 66 can smooth some of the in-band ripple, resulting in a smaller difference between the corresponding gain peaks at the first frequency pole 110 and the second frequency pole 112. However, the overall frequency response gain is also reduced. That is, by reducing the gain difference between peaks, the peaks can become relatively more uniform (e.g., compared to the case without series resistors 64 and 66), but with a lower overall gain at each peak at the corresponding frequency poles 110 and 112 and between these peaks. Lower gain peaks correspond to higher reflection of the output signal, resulting in relatively large output signal loss.

[0093] In addition to adding series resistors 64 and 66, or as an alternative, resonator 50 may be implemented with shunt resistors 60 and 62. As shown in the third curve 106, shunt resistors 60 and 62 can further smooth some of the in-band ripple, resulting in a smaller difference between the corresponding peak gains at the first frequency pole 110 and the second frequency pole 112. However, the overall frequency response gain (including the frequency poles) is also reduced. That is, by reducing the gain difference between peaks, the peaks can become relatively more uniform (e.g., compared to the case without shunt resistors 60 and 62), but with a lower overall gain at each peak at the corresponding frequency poles 110 and 112. As previously mentioned, lower gain peaks can indicate higher reflections of the output signal at the corresponding frequency poles 110 and 112, resulting in relatively large output signal loss. Therefore, shunt resistors 60, 62 and / or series resistors 64, 66 can reduce the in-band ripple effect of the output signal, but may impair the gain at each frequency (including the first frequency pole 110 and the second frequency pole 112).

[0094] In some cases, simply adjusting the coupling coefficient may not provide a tuning effect that reduces the non-uniform gain of the output signal. Thus, as mentioned earlier, the non-uniform gain peaks caused by the even-mode and odd-mode currents through the transformer-based resonator 50 may be difficult to reduce.

[0095] The gain peak at the first frequency pole 110 (e.g., a low-frequency pole) is associated with the Q factor of the sum of the inductance and the coupling inductance (e.g., the coupling gain peak). On the other hand, the gain peak at the second frequency pole 112 (e.g., a high-frequency pole) is associated with the Q factor of the leakage inductance. At higher frequencies, the leakage inductance may have a lower Q factor due to the less efficient magnetic flux loop. When the electronic device 10 transmits an output signal, the resonator 50 of the RF filter circuit, which causes the frequency response to have non-uniform gain peaks that generate spikes and in-band ripple, can result in poor EVM and SNR values. This can lead to filter instability and / or an unstable output signal. Tuning the resonator 50 to address in-band ripple by tuning capacitors 56, 68 and / or resistors 60, 62 (e.g., to "Q-remove" the output signal) and / or adding shunt resistors 60, 62 and / or series resistors 64, 66 to the resonator 50 can result in an output signal with impaired transmission gain (e.g., excessive and / or undesirable reduction).

[0096] Transmitting an output signal with lower gain can cause electronic device 10 to transmit a degraded signal due to increased reflection loss, resulting in a degraded form of wireless communication. In some cases, the gain peak may fall below a predefined threshold for transmitting the output signal from transceiver 30. By way of example, the threshold gain peak may include a gain value or range of values ​​that allows the antenna of transceiver 30 to transmit the output signal with a predefined power (e.g., low reflection), thereby indicating reliable or expected wireless communication quality. That is, if the gain of the output signal at a particular frequency is below this threshold, electronic device 10 with RF filtering circuitry with a resonator may not be able to transmit the output signal in the expected manner.

[0097] In addition to adjusting the parameters of resonator 50 (e.g., by adjusting the Q factor and / or coupling coefficient) using capacitors (e.g., first capacitor 56 and second capacitor 58), resistors (e.g., first resistor 57 and / or second resistor 59), and / or shunt resistors and series resistors (e.g., shunt resistors 60, 62 and series resistors 64, 66), or alternatively, resonator 50 may be implemented with a ripple reduction loop that includes a third inductor with an additional resistor. Specifically, the ripple reduction loop may be used to adjust the coupling coefficient, rather than the Q factor, which may be finite.

[0098] For example, Figure 11A A resonator 51 according to an embodiment of the present disclosure is depicted, which may include a resonator with... Figure 9A The resonator 51 uses the same components as the resonator 50, as well as a ripple reduction circuit 130 (e.g., a Q-reduction circuit). The ripple reduction circuit 130 includes a third inductor 120 (L3) and an additional resistor 122 (R7). The resonator 51 may also include a first inductor 52, a second inductor 54, a first capacitor 56, a second capacitor 58, a first resistor 57, and a second resistor 59. In some embodiments, the resonator 51 may include a first shunt resistor 60, a second shunt resistor 62, a first series resistor 64, and / or a second series resistor 66. Generally, the resonator 51 can implement ripple reduction techniques for broadband filters in the 24-48 GHz frequency range.

[0099] These components can provide relative to Figures 9A to 9C The same or similar corresponding functions. Figure 11B and Figure 11C A resonator 51 according to an embodiment of the present disclosure is depicted, which includes a resonator 51 with a resonator 52 with a resonator 53 with a resonator 54 with a resonator 55 with a resonator 56 with a resonator 57 with a resonator 58 with a resonator 59 with a resonator 51 ... Figure 9B and Figure 9C The resonator 50 has the same corresponding components, but with a ripple reduction circuit 130, which has a third inductor 120 and an additional resistor 122. Figure 11BAs shown, the third even-mode current 72C flowing through the third inductor 120 can follow the same direction as the coils in the first inductor 52 and the second inductor 54. Specifically, the first even-mode current 72A through the first inductor 52 can induce a second even-mode current 72B in the second inductor 54, and a third even-mode current 72C in the third inductor 120. The second inductor 54 can also induce a third even-mode current 72C in the third inductor 120. Although not shown, in some embodiments, a portion (e.g., one-third or approximately one-third) of the total current 70 through the first inductor 52 can be transferred to each of the second inductor 54 and the third inductor 120.

[0100] On the other hand, Figure 11C Since the first odd-mode current 74A flowing through the first inductor 52 and the second odd-mode current 74B flowing through the second inductor 54 flow in opposite directions and have equal magnitudes, the currents cancel each other out, resulting in no current flowing into the third inductor 120. Therefore, the first odd-mode current 74A and the second odd-mode current 74B do not flow through the additional resistor 122.

[0101] The ripple reduction circuit 130 facilitates matching the gain peaks of the two frequency poles 110, 112. Specifically, the ripple reduction circuit 130 reduces the gain of the first frequency pole 110 (e.g., a low-frequency pole) without affecting or minimally affecting the gain of the second frequency pole 112 (e.g., a high-frequency pole), which is related to the leakage inductance Q factor. The ripple reduction circuit 130 also minimizes or does not affect the gain of the output signal at frequencies between the frequency poles 110, 112. That is, the ripple reduction circuit 130 substantially maintains the gain of the output signal (e.g., maintains the gain of the output signal at approximately every frequency except the low-frequency pole) while reducing the in-band ripple caused by the frequency poles 110, 112. In some embodiments, the ripple reduction circuit 130 minimizes the gain between the first frequency pole 110 and the second frequency pole 112. However, the gain between the first frequency pole 110 and the second frequency pole 112 may already be significantly lower than that of poles 110 and 112, and therefore the ripple reduction loop 130 may not reduce the gain as much as it would for the gain peaks at poles 110 and 112. Therefore, compared to other filter parameter tuning methods that may impair the gain at the peaks at the two frequency poles 110 and 112, the ripple reduction loop 130 controls and promotes matching (e.g., correlation) between the gain peak of the first frequency pole 110 and the gain peak of the second frequency pole 112.

[0102] In some embodiments, the additional resistor 122 may be a fixed resistor (e.g., providing a single fixed resistance). In other embodiments, the additional resistor 122 may be a programmable variable resistor that provides variable resistance. In such embodiments, the additional resistor 122 may include components for changing the amount of current flowing through the resonator 51 (e.g., a controller with a processor, such as processor 12). Thus, the ripple reduction loop 130 including the additional resistor 122 can dynamically adjust the gain to provide dynamic ripple reduction. The gain at the second frequency pole 112 may vary, for example, based on factors external to the resonator 50 (e.g., the input signal and / or environmental factors). In such cases, the ripple reduction loop 130 can adjust the additional resistor 122 to reduce the gain at the first frequency pole 110 and according to the second frequency pole 112 (e.g., associated with or approximately matched to the second frequency pole 112). Furthermore, the additional resistor 122 may be programmed to be a specific resistor to change the gain and smooth the frequency response in the presence of multiple poles (e.g., three or more cascaded poles) that cause in-band ripple. In such cases, the additional resistor 122 can be programmed to have different resistance values ​​based on each of the poles and the gain difference between the poles.

[0103] Figure 12 A resonator 51 on a silicon chip is shown. While the following discussion describes a resonator 51 implemented on a PCB representing a particular embodiment, the resonator 51 may instead be implemented on a silicon chip or integrated circuit. As shown, according to an embodiment of this disclosure, a first inductor 52 (indicated by a bright spot pattern), a second inductor 54 (indicated by a dark spot pattern), and a ripple reduction circuit 130 (indicated by no pattern) may be stacked on a PCB 55. The first inductor 52, the second inductor 54, and / or the ripple reduction circuit 130 may be mounted on the PCB 55 and / or etched (e.g., positioned) onto one or more layers of the PCB 55. Here, the ripple reduction circuit 130 is positioned on a first (e.g., lower) layer of the PCB 55. The first inductor 52 is positioned on a second (e.g., higher) layer of the PCB 55, and the second inductor 54 is positioned on a third (e.g., higher) layer of the PCB 55.

[0104] In some implementations, inductors 52, 54, 120 and / or portions of inductors 52, 52, 120 may be disposed on separate layers of PCB 55. For example, a portion of the coil of a third inductor 120 may be located on a first layer, while another portion of the coil of the third inductor 120 may be located on a second layer or another layer. Similarly, a portion of the coil of a first inductor 52 may be located on a second layer, while another portion of the coil of the first inductor 52 may be located on a third layer or another layer. In such implementations, these portions may be coupled using vias 53, allowing current flowing through the first inductor 52 to flow between the two layers without obstruction. Similarly, a second inductor 54 may also include a portion of its coil on a third layer, while another portion of its coil is located on a fourth (e.g., above the third) layer or another layer. The second inductor 54 may also include vias 53 to couple these portions together.

[0105] As shown, the ripple reduction circuit 130 is a conductive circuit (e.g., a metal circuit) comprising a third inductor 120 connected in series and an additional resistor 122. Although the description of the ripple reduction circuit 130 as a conductive circuit indicates a particular embodiment, the ripple reduction circuit 130 may additionally or alternatively include one or more metal coils, wherein portions of the coils are located on different layers in the stacked architecture of the resonator 51 as described above. The first inductor 52 and the second inductor 54 may be symmetrical, such that they are made of the same material, have the same thickness, have the same length, have the same dimensions, and / or have the same number of coils. In some embodiments, the ripple reduction circuit 130 may be relatively thinner than the first inductor 52 and the second inductor 54. Specifically, the first inductor 52 may have a first thickness (e.g., a first cross-sectional width or diameter), the second inductor 54 may have a second thickness (e.g., a second cross-sectional width or diameter), and the reduction circuit 130 may have a third thickness (e.g., a third cross-sectional width or diameter). The third thickness may be less than the first thickness and less than the second thickness. For example, the first inductor 52 and the second inductor 54 may be 2-3 micrometers (μm), and the reduction loop may be 0.1 μm.

[0106] As previously described, the first even-mode current 72A flowing through the first inductor 52 can induce a second even-mode current 72B flowing through the second inductor 52 in the same direction (e.g., both clockwise or both counterclockwise). This positive feedback of the even-mode currents 72A and 72B in the same direction can induce a third even-mode current 72C in the third inductor 120. Specifically, the first inductor 52 can induce at least a portion of the third even-mode current 72C in the third inductor 120, and the second inductor 54 can induce at least a portion of the third even-mode current 72C in the third inductor 120. As will be discussed herein, the additional resistor 122 can adjust the parameters of the resonator 51 to change the frequency response of the input signal through the resonator 51. For example, the additional resistor 122 can reduce the gain peak of the first frequency pole 110 to correlate with or substantially correlate with the gain peak of the second frequency pole. As previously mentioned, the even-mode currents through resonators 50 and / or 51 can correspond to low-frequency poles, while the odd-mode currents can correspond to relatively high-frequency poles.

[0107] When the first inductor 52 receives a first odd-mode current 74A, the first odd-mode current 74A can transfer a current such as a second odd-mode current 74B to the second inductor 54. A second odd-mode current 74B is induced relative to the first odd-mode current 74A in an equal magnitude but in the opposite direction (e.g., clockwise in the first inductor 52 and counterclockwise in the second inductor 54). As previously stated, the opposite currents prevent current transfer to the third inductor 120 by canceling each other out. Therefore, current cannot flow through the additional resistor 122. Thus, adjusting the filter parameters (e.g., coupling coefficient) of the resonator 51 via the additional resistor 122 to reduce in-band ripple can affect the even-mode current corresponding to the low-frequency peak. As previously stated, the additional resistor 122 can be a variable resistor or a fixed resistor. As a variable resistor, the additional resistor 122 can be programmed based on the desired ripple reduction effect. The additional resistor 122 can also be programmed to vary during operation and therefore can be dynamically programmed based on operating conditions. Alternatively or otherwise, the additional resistor 122 may be set as a fixed resistor based on test simulations during equipment manufacturing. Specifically, the additional resistor 122 may be fixed to a set resistor for the type and / or model of equipment that typically operates in a similar manner during operation.

[0108] For clarity, according to the implementation scheme of this disclosure, Figure 13A This is a schematic diagram showing a cross-sectional view of the resonator 51, and Figure 13BThis is a schematic perspective view showing the resonator 51. As shown, a first inductor 52 (indicated by a bright spot pattern), a second inductor 54 (indicated by a dark spot pattern), and a ripple reduction circuit 130 (indicated by no pattern) including a third inductor 120 with an additional resistor 122 can be stacked on a PCB 55 (not shown). The first inductor 52, the second inductor 54, and / or the ripple reduction circuit 130 can be mounted on the PCB 55 and / or etched (e.g., positioned) onto one or more layers of the PCB 55. The ripple reduction circuit 130 is positioned on a first layer 132A (e.g., a lower layer) of the PCB 55. The first inductor 52 is positioned on a second layer 132B (e.g., above the first layer) of the PCB 55, and the second inductor 54 is positioned on a third layer 132C (e.g., above the second layer) of the PCB 55. In some cases, and as previously described, a portion of the first inductor 52, the second inductor 54, and / or the third inductor 120 of the ripple reduction circuit 130 may be located on one or more layers. For example, a portion of the second inductor 54 may be located on the third layer 132C, while another portion of the second inductor 54 may be located on a fourth layer 132D (e.g., above the third layer 132C), wherein these portions are connected via vias 53. The architecture and function of the resonator 51 may be implemented as previously described.

[0109] Figure 14 A graph 200 is depicted according to an embodiment of this disclosure, illustrating the frequency response of the output signal through the operating region of the resonator 51. A first curve 102 illustrates the frequency response of the output signal of the resonator 50 without the ripple reduction circuit 130. A second curve 202 illustrates the frequency response of the output signal of the resonator 51 with the ripple reduction circuit 130 implemented. (As relative to...) Figure 12 The ripple reduction circuit 130 discussed herein can smooth the gain of the frequency response over the operating region, including the gain peaks at a first frequency pole 110 (e.g., a low-frequency pole) and a second frequency pole 112 (e.g., a high-frequency pole), as well as the gain of the output signal at frequencies between the low-frequency pole and the high-frequency pole. The ripple reduction circuit 130 can smooth the gain of the frequency response over the operating region, for example, by using an additional resistor 122 to correlate the gain peak at the low-frequency pole to the high-frequency pole.

[0110] As shown in the figure, curve 102 illustrates a sharp difference between the gain peaks of the first frequency pole 110 and the second frequency pole 112. This difference between peaks results in a 2 dB in-band ripple (e.g., a drop between peaks). However, due to the ripple reduction loop 130 of resonator 51, the difference between peaks is reduced in curve 202. Specifically, the ripple reduction loop smooths the frequency response over the operating region of resonator 51 by matching the gain peak of the first frequency pole 110 to the gain peak of the second frequency pole 112, such that the difference results in a 0.8 dB in-band ripple. Thus, the system and method described herein with resonator 51 having the ripple reduction loop 130 facilitates smoothing the frequency response of the output signal through resonator 51 while minimizing gain loss.

[0111] The techniques described herein and protected by the claims are referenced and applied to specific examples of physical and practical nature, which significantly improve the technical field and are therefore not abstract, intangible, or purely theoretical. Furthermore, if any claim appended to the end of this specification contains one or more elements designated as "means for [performing] [function]..." or "steps for [performing] [function]...", those elements shall be interpreted in accordance with 35U.SC112(f). However, for any claim containing elements designated in any other manner, those elements shall not be interpreted in accordance with 35U.SC112(f).

Claims

1. A radio frequency filter circuit, comprising: A first inductor is coupled to a current source and disposed on a first layer of a printed circuit board; A second inductor is disposed on a second layer of the printed circuit board, the second layer being disposed below the first layer, and the first inductor being offset from the second inductor to form an overlapping area. as well as A conductive loop is disposed on the third layer of the printed circuit board and located within the overlapping area formed by the first inductor and the second inductor; The second inductor is configured to be inductively coupled to the first inductor based on a first current supplied to it by the current source, the first current inducing a second current in the second inductor, and the second current inducing a third current traveling through the conductive loop; and The third current reduces the in-band ripple between the first gain peak and the second gain peak of the output signal of the RF filter circuit.

2. The radio frequency filter circuit according to claim 1, wherein the direction of the even-mode current flow of the second current corresponds to the direction of the even-mode current flow of the first current, thereby inducing the third current in the conductive circuit.

3. The radio frequency filter circuit according to claim 1, wherein the direction of the odd-mode current flow of the second current is opposite to the direction of the odd-mode current flow of the first current, preventing current transfer to the conductive loop.

4. The radio frequency filter circuit according to claim 1, wherein the first current and the second current induce the third current in the conductive circuit.

5. The RF filter circuit of claim 1, wherein the third current of the conductive loop reduces the in-band ripple between the first gain peak and the second gain peak by reducing the first gain peak to correspond to the second gain peak.

6. The radio frequency filtering circuit according to claim 1, wherein the first gain peak corresponds to a first frequency response of the output signal, and the second gain peak corresponds to a second frequency response of the output signal.

7. The radio frequency filtering circuit of claim 6, wherein the second frequency response corresponds to a higher frequency band compared to the first frequency response.

8. The radio frequency filter circuit according to claim 1, wherein the third current reduces the in-band ripple to less than or equal to 1 dB.

9. The radio frequency filtering circuit of claim 1, wherein the physical relationship between the first inductor, the second inductor and the conductive loop enables the reduction of the in-band ripple between the first gain peak and the second gain peak of the output signal.

10. A processing circuit, comprising: First inductor; A second inductor, wherein the first inductor is arranged to form a resonant circuit with the second inductor; as well as A third inductor is configured relative to the first and second inductors to add or remove current from the output signal of the processing circuit. The first inductor is configured to induce a second current in the second inductor at least in part based on the magnetic flux caused by the first current, and the second inductor is configured to induce a third current in the third inductor at least in part based on the magnetic flux caused by the second current; and The third current reduces the in-band ripple between the first gain peak and the second gain peak of the output signal.

11. The processing circuit of claim 10, wherein the second inductor is offset from the first inductor.

12. The processing circuit of claim 10, wherein the third inductor includes a variable resistor configured to dynamically adjust the gain of the first gain peak, the second gain peak, or both, to reduce the in-band ripple between the first gain peak and the second gain peak.

13. The processing circuit of claim 10, wherein the in-band ripple is reduced to approximately 0.8 dB.

14. The processing circuit of claim 10, wherein the first inductor and the second inductor are disposed on a printed circuit board to form an overlapping region, and wherein the third inductor is disposed within the overlapping region formed by the first inductor and the second inductor.

15. An electronic device comprising: A transmitter configured to transmit the output signal of the radio frequency filtering circuitry of the electronic device via one or more antennas; At least one processor, the at least one processor being configured to cause the transmitter to transmit the output signal via the one or more antennas; A current source, configured to generate a first current; The radio frequency (RF) filter circuit, configured to provide the output signal, includes... A first coil, disposed on a first layer of a printed circuit board and coupled to the current source, is configured to receive a first current from the current source. A second coil, disposed on a second layer of the printed circuit board and offset from the first coil, is configured to provide a second current induced by the first current traveling through the first coil, and A conductive circuit in which a second current traveling through a second coil induces a third current in the conductive circuit, and the output signal of the radio frequency filter circuit is based on the first current, the second current, and the third current; as well as A resistor coupled to the conductive loop and configured to adjust the third current to reduce the in-band ripple between the first gain peak and the second gain peak of the output signal.

16. The electronic device of claim 15, wherein the resistor comprises a programmable resistor or a fixed resistor.

17. The electronic device of claim 15, wherein the first coil and the second coil form an overlapping area on the printed circuit board, and wherein the conductive loop is disposed within the overlapping area formed by the first coil and the second coil.

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