A method for adding an antenna to a mobile phone key

Abstract

The application relates to the technical field of mobile communication terminal antennas, and discloses a method for adding an antenna to a mobile phone key, which comprises the following steps: monitoring a key logic signal output by a microswitch in a side key assembly in real time; when a level jump of the key logic signal is detected, it is determined that the key is in a pressed state, a compensation reactance value is obtained based on a preset load capacitance increment, and corresponding radio frequency scheduling instructions are generated; the radio frequency scheduling instructions are used to drive an adjustable impedance matching network to adjust an impedance topology structure, and a compensation reactance component is accessed in a feeding link. The application converts a mechanical operation state into a radio frequency control input, dynamically offsets parasitic parameter changes caused by finger dielectric coupling and key displacement, compensates for antenna resonance frequency offset, and guarantees continuous conduction of a radio frequency receiving and transmitting link of a terminal device during physical pressing interaction.

Description

Technical Field

[0001] This invention relates to the field of mobile communication terminal antenna technology, specifically a method for adding an antenna to a mobile phone button. Background Technology

[0002] As mobile communication terminals become thinner and more integrated, the available space inside the device for RF antennas is gradually shrinking. To improve space utilization, existing technologies propose reusing physical buttons on the side of the terminal as antenna radiators. This typically involves placing conductive patterns inside the insulated button body and connecting it to the internal motherboard RF transceiver link via elastic contacts.

[0003] In actual operation, physical buttons simultaneously perform mechanical interaction and electromagnetic radiation functions. The electromagnetic physical boundaries of a button in free space and when pressed differ significantly. When a user presses the button, the surface tissue of the finger adheres to the outer side of the button, introducing additional human-equivalent parasitic capacitance into the RF network due to the dielectric coupling effect. Simultaneously, the button undergoes mechanical displacement inward, bringing the antenna radiator closer to the internal metal grounding motherboard. The reduced electrode spacing further increases the equivalent distributed capacitance of the parallel plates. This transient surge in load capacitance caused by both mechanical displacement and dielectric proximity directly disrupts the antenna's original input impedance matching, leading to a significant deviation of the antenna resonant frequency from the target operating frequency band, resulting in a deterioration of the system's reflection coefficient and a momentary interruption of the RF transceiver link.

[0004] To address the aforementioned frequency offset issue, most existing RF dynamic impedance matching technologies rely on passive feedback tuning based on baseband chip readings of received signal strength or bit error rate. This closed-loop mechanism suffers from significant sensing and processing delays, making it impossible to achieve synchronous feedforward compensation with millisecond-level transient button mechanical actions. Furthermore, during impedance adjustment, if the terminal is operating under high-power RF transmission conditions, directly driving switching components to switch the impedance network topology can easily cause a surge in transient VSWR in the feed link, risking breakdown of the RF front-end power amplifier by a reverse high-power signal. On the other hand, when buttons multiplexed as antennas radiate high-frequency electromagnetic radiation, RF energy can easily couple to adjacent microswitch pin traces, forming transient voltage spikes. Existing simple hardware debouncing logic struggles to effectively distinguish between the actual mechanical release action of the button and RF coupling interference, easily receiving spurious transition levels and sending incorrect matching recovery commands to the RF network, thus reducing communication stability during button press interactions. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for adding antennas to mobile phone buttons, which solves the problem that when physical buttons are reused as radio frequency antennas, the antenna input impedance changes abruptly due to the medium coupling effect of human fingers and the mechanical displacement of the buttons, thereby causing resonant frequency shift and interruption of radio frequency signal transmission and reception.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The method provided by this invention is applied to a terminal device including a mobile phone motherboard, a radio frequency transceiver module, an adjustable impedance matching network, and a side button assembly. The side button assembly consists of an insulated button body and a micro switch, and a conductive pattern is arranged inside the insulated button body as an antenna radiator.

[0008] The basic operating logic of this invention is as follows: By monitoring the button logic signals of the microswitch in real time and capturing its level transition events, the system determines the pressed state of the side button assembly. This determined mechanical state triggers a feedforward control mechanism to generate RF scheduling commands, directly driving the adjustable impedance matching network to adjust the internal impedance network topology. This mechanism introduces a reverse compensation reactance during the synchronization period of the pressed state, offsetting the frequency deviation caused by changes in the mechanical and dielectric environment, ensuring continuous conduction of the RF transceiver link during physical interaction.

[0009] In one design, to establish a physical reference for the compensation parameters, the system defines the load capacitance increment based on the superposition of the two physical effects caused by the pressing action.

[0010] One is the equivalent parasitic capacitance of the human body generated by the dielectric coupling effect. This value characterizes the change in electromagnetic boundary introduced when the finger surface tissue is attached to the outside of the insulated key. Secondly, there is the equivalent distributed capacitance value of the parallel plates. This value characterizes the effect of reduced plate spacing caused by the mechanical displacement of the button inward, which brings the antenna radiator closer to the metal grounding motherboard. Based on the equivalent input reactance change determined by the above-mentioned load capacitance increment, the model basis for subsequent calculation of the target compensation reactance value is formed.

[0011] Furthermore, to control system processing latency and reduce the complex operation load on the baseband processing unit, this scheme employs a multi-dimensional state mapping query mechanism to obtain compensation parameters. The system obtains the currently active operating frequency band identifier and level state in real time, combines them to form a joint index key, and directly retrieves the theoretical compensation reactance value from a preset impedance compensation lookup table. Subsequently, the system executes the minimum absolute value error decision logic, traversing all fixed discrete impedance levels supported by the adjustable impedance matching network, and retrieving and outputting the level with the smallest difference from the theoretical value as the target matching topology parameter. This process completes the transformation from a continuous impedance theoretical model to a discrete physical switch state matrix.

[0012] At the hardware execution level, the adjustable impedance matching network parses RF scheduling commands and connects corresponding inductors or capacitors in the power supply link by closing or opening its internal RF microelectromechanical switches or MOSFET arrays. To prevent impedance surges and component damage under high power conditions, the system incorporates operating condition alignment and hot-switching protection mechanisms before executing physical switching actions. When the current RF transmit power exceeds a preset safety threshold, the system forcibly triggers the power sag mechanism of the baseband transmit module. Only after confirming that the link is in a low-power safe operating condition is the impedance network topology reconstructed, and the original transmit power is restored after the switch is completed. This timing control avoids the RF power amplifier breakdown problem caused by a surge in transient VSWR.

[0013] To address the rebound reset process after button release, considering that antenna RF energy may couple to the microswitch traces, causing transient voltage spikes, this solution introduces a multi-source weighted detection mechanism based on a sliding time window. The system discretely samples the pin voltage at a preset sampling period and calculates the confidence weight of sampling points that meet the low-level condition within a constant-length sliding data window in real time. Only when the confidence weight meets the judgment threshold, and the duration of this state reaches the release debounce time window condition, does the system confirm the component's rebound reset and issue a reset command to remove the compensating reactance element. This mechanism achieves quantized fault tolerance and effective filtering of transient RF interference.

[0014] In terms of system-level coordination, the baseband processing unit performs cross-level synchronous distribution within the same processing cycle upon receiving a level transition: on the one hand, it transmits mechanical interaction instructions to the upper-layer operating system to execute interface logic; on the other hand, it sends RF scheduling instructions, encapsulated in a standard data frame structure, in real time via the RF front-end control bus of the mobile industry processor interface. During this data flow, the system employs a preset tolerance window alignment logic to strictly constrain the time lag from sensing the press to the actual initiation of physical compensation within the maximum RF compensation time tolerance window allowed by the communication standard data frame, thus maintaining the communication time slot alignment of the time division multiplexing system.

[0015] Furthermore, to ensure the physical continuity of the aforementioned dynamic electrical compensation process, the antenna radiator is equipped with elastic conductive contacts capable of deformation compensation. These contacts absorb assembly and operational displacement tolerances throughout the entire inward mechanical displacement of the button, maintaining connection with the adjustable impedance matching network. When the microswitch signal is in its initial, unchanging state, the system controls the matching network to maintain the initial parameters corresponding to free space, forming a complete closed loop of state monitoring and physical feedback.

[0016] This invention provides a method for adding an antenna to a mobile phone button. It has the following beneficial effects: 1. This invention generates radio frequency scheduling commands by real-time monitoring of the level transitions of microswitches, which directly drive the adjustable impedance matching network to adjust the impedance topology. This cancels out the dielectric coupling parasitic capacitance caused by finger contact with the insulated button, as well as the increase in parallel plate distributed capacitance caused by button displacement. This keeps the antenna's resonant frequency within the target operating frequency band during physical pressing, maintains the convergence of the system's reflection coefficient, and maintains the continuous conduction of the radio frequency transceiver link of the terminal device throughout the entire mechanical interaction process.

[0017] 2. Before changing the impedance network topology, this invention sets up a condition alignment and hot switching mechanism. By comparing the current RF transmit power with a preset safety threshold, the power sag mechanism of the baseband module is triggered when the threshold is exceeded. The physical action of the microelectromechanical switch or field-effect transistor is executed only after the power supply link is in a low power state. This step limits the peak value of the system's standing wave ratio at the moment of impedance switching and eliminates the condition that the front-end RF power amplifier will be physically broken down due to the back reflection of high-power RF signals.

[0018] 3. This invention employs a multi-source weighted detection logic based on a sliding time window for the button rebound reset process. By discretely sampling the pin voltage and calculating the confidence weight of the sampling points within a constant window, combined with the preset release anti-shake time condition, the output status indicator is filtered out. This filters out transient voltage spikes caused by the coupling of high-power RF energy from the antenna to the switch signal trace, and avoids the baseband processing unit from instructing the adjustable impedance matching network to perform incorrect topology reconstruction actions due to receiving pseudo-jump signals. Attached Figure Description

[0019] Figure 1 This is a system architecture diagram for adding an antenna to a mobile phone button according to an embodiment of the present invention; Figure 2 This is a flowchart of a method for adding an antenna to a mobile phone button according to an embodiment of the present invention; Figure 3 A comparison diagram of the frequency response of antenna S11 parameters provided in an embodiment of the present invention; Figure 4 A comparison diagram of the time-domain dynamic response of terminal transmit power provided in an embodiment of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] See attached document Figure 1The terminal device provided in this embodiment includes a mobile phone motherboard, an RF transceiver module, an adjustable impedance matching network, and a side button assembly. The side button assembly provides a physical interface for the user while also serving as a carrier for transmitting and receiving RF signals.

[0022] In a preferred embodiment, the side button assembly includes an insulated button body and a microswitch. The inner surface of the insulated button body has a conductive pattern, which serves as an antenna radiator. The antenna radiator is electrically connected to the RF transceiver module via an adjustable impedance matching network.

[0023] As a specific implementation of the hardware architecture, the adjustable impedance matching network internally includes an RF microelectromechanical switch or a field-effect transistor array, configured to switch internally inserted series-inductor or parallel-inductor components or capacitor components according to external commands. The RF transceiver module is implemented based on conventional RF transceiver chips and matching RF front-end modules in the art. For the specific topology of the low-noise amplifier, power amplifier, and modulation / demodulation circuit within the RF transceiver module, those skilled in the art can make conventional selections based on the actual communication frequency band requirements.

[0024] See attached document Figure 2 One embodiment of the present invention provides a method for adding an antenna to a mobile phone button, which is implemented based on the aforementioned physical hardware architecture and uses a baseband processing unit on the mobile phone motherboard for cross-level system scheduling. Based on the aforementioned system architecture, the workflow of RF impedance adaptive compensation includes the following steps: S100, the signal pin of the microswitch is electrically connected to the general-purpose input / output interface of the mobile phone motherboard. During system power-on or RF idle periods, the baseband processing unit monitors the button logic signal output by the microswitch in real time. When the button logic signal is detected to be in an initial high-impedance state without transition or a preset low level, the system determines that the side button assembly is in a free-space state. In this state, the baseband processing unit controls the adjustable impedance matching network to maintain the initial impedance matching parameters corresponding to the free-space state and maintains the monitoring state of the button logic signal.

[0025] S200: When a level transition is detected in the key logic signal, the side key assembly is determined to be in a pressed state. In practical engineering, the metal spring of a mechanical key often experiences high-frequency physical jitter at the moment of closure. To avoid frequent reconfiguration of the RF network due to misjudgments caused by transient level extremes, this embodiment introduces a multi-dimensional state determination mechanism based on time window constraints.

[0026] During the process of determining whether the side button component is pressed, the baseband processing unit uses a comparison mechanism based on both threshold and duration constraints to determine the level transition state. The current sampling time is set to... The real-time voltage level collected by the baseband processing unit is The threshold voltage for triggering the microswitch is set to be The preset mechanical image stabilization time window is The calculation expression for this transition determination mechanism is as follows: ; In the formula, This refers to the status identifiers recorded by the system. for Continuously greater than or equal to the threshold voltage The continuous cumulative time.

[0027] Among them, threshold voltage The specific value is determined according to the electrical specifications of the mobile phone motherboard's general input / output interface, and is typically 70% of the interface's power supply voltage. Mechanical image stabilization time window. The value range is generally set to 10ms to 20ms, and its specific parameters are calibrated based on the physical rebound attenuation characteristics of the microswitch spring. This decision logic filters transient high-frequency interference, ensuring that the system only switches states when the user's finger applies a stable physical pressing action.

[0028] when When the value is maintained at 0, the system remains in free space. When the signal transitions from 0 to 1, the baseband processing unit determines that a valid level change has occurred and enters the processing logic of the pressed state. After determining that it has entered the pressed state, the baseband processing unit performs cross-level synchronization processing operations within the same processing cycle that received the level change.

[0029] Specifically, the baseband processing unit uses an internal hardware interrupt mechanism to send corresponding mechanical button interaction commands to the upper-level operating system to execute interface operation logic such as volume adjustment or power control. In parallel, the underlying RF scheduler generates RF scheduling instructions corresponding to the pressed state.

[0030] S300, the baseband processing unit sends the RF scheduling command generated in the aforementioned steps to the underlying RF control bus. In this embodiment, the underlying RF control bus is preferably the mobile industry processor interface RF front-end control bus, which has microsecond-level low-latency communication characteristics.

[0031] The adjustable impedance matching network receives the RF scheduling command, parses the command content, and adjusts the impedance network topology accordingly. Thanks to the high-speed response of the underlying bus, the adjustment of the impedance network topology can be synchronized with the mechanical pressing action in the time domain, thereby compensating for the antenna resonant frequency shift caused by pressing the insulated button and avoiding the loss of communication data packets.

[0032] S400: The baseband processing unit continuously polls the level state of the micro switch. After the user physically releases the insulated button body, the micro switch disconnects under mechanical force. When the baseband processing unit detects that the level of the button logic signal has returned to its initial state before the transition and also meets the anti-bounce time window condition, it determines that the side button assembly has rebounded and reset.

[0033] The baseband processing unit generates a reset command and sends it to the adjustable impedance matching network. In response to the reset command, the adjustable impedance matching network removes the reactive components previously used for frequency offset compensation, restoring the impedance network topology to its free-space state before the reset.

[0034] In this embodiment, the internal structure of the side button assembly is meticulously arranged in its hardware structure to support stable transmission and reception of radio frequency signals and physical sensing of pressing actions.

[0035] In this embodiment, the insulated button body of the side button assembly is preferably injection molded from a non-conductive polymer material such as polycarbonate or glass fiber. The inner surface of the insulated button body is patterned using a laser direct forming process or a flexible printed circuit board (PCB) attachment process. This conductive pattern physically serves as the antenna radiator of the radio frequency system.

[0036] For the principle of metallization wiring on non-metallic surfaces using laser direct forming technology, those skilled in the art can refer to existing mature mobile phone antenna manufacturing processes.

[0037] During actual press-to-action interaction, the spatial position of the antenna radiator dynamically changes while the side button assembly is pressed and undergoes inward mechanical displacement. To maintain the stability of the feed link, this embodiment incorporates an elastic conductive contact between the antenna radiator and the adjustable impedance matching network.

[0038] As a specific feature of this elastic conductive contact, the system employs a C-shaped beryllium copper metal spring or conductive foam with deformation compensation capability. When the insulated button body is subjected to force and moves inward into the terminal device, the elastic conductive contact undergoes compressive deformation and absorbs mechanical displacement tolerance, thereby continuously maintaining dynamic electrical continuity between the antenna radiator and the adjustable impedance matching network. This physical connection mechanism ensures that subsequent adjustments to the impedance network topology can continue to effectively act on the antenna radiator.

[0039] Based on the above physical configuration, the evolution of the radio frequency mismatch mechanism of the terminal device when subjected to mechanical pressure follows strict electromagnetic physical laws. To clarify the source of the compensation parameters, the following sub-steps provide a detailed analysis of the evolution of its physical environment and the mismatch mechanism.

[0040] S210, based on fundamental electromagnetic theory of antenna design, any radio frequency radiator can be equivalently represented as a lumped parameter network containing inductance and capacitance. When the system determines that it is in the free space state described in step S100, the antenna radiator is not disturbed by any external objects. At this time, the antenna radiator possesses an inherent equivalent inductance. and inherent equivalent capacitance In this physical space environment, the initial resonant frequency of the antenna system The following physical relationship must be satisfied: ; In the formula, the initial resonant frequency is... The antenna is calibrated and aligned to the target operating frequency of the RF system during the equipment's design phase at the factory. Due to the objective existence of the antenna as a physical entity, its inherent equivalent inductance... With inherent equivalent capacitance All are always greater than zero.

[0041] S220, when the user interacts with the side button component and presses it, the physical environment of the antenna radiator changes, thus introducing an additional distributed capacitance variable into the antenna system. This distributed capacitance variable is defined as a preset load capacitance increment. The value of this load capacitance increment corresponds to the superposition of the two physical effects triggered by the pressing action, and its calculation expression is as follows: ; In the formula, This is the first capacitance increment. This is the second capacitance increment.

[0042] Specifically, the first capacitance increment characterizes the effect produced when a human finger adheres to the outer surface of the insulated button body. The finger surface tissue acts as a conductive medium, separated from the inner antenna radiator by the insulated button body, generating an equivalent parasitic capacitance value of the human body based on the medium coupling effect.

[0043] The second capacitance increment characterizes the effect of button structure displacement. When the insulated button body undergoes mechanical displacement into the terminal device, the antenna radiator approaches the metal grounded motherboard inside the phone, reducing the distance between their plates. Based on the principle of parallel plate capacitors, this increases the equivalent distributed capacitance value of the parallel plates.

[0044] As the physical causal basis for extracting engineering parameters, The value is directly positively correlated with the effective contact area between the finger and the insulated button body, and is limited by the relative permittivity of the polymer insulating material; and The value depends on the micromechanical travel of the inward movement of the insulated button body, which is typically constrained to between 0.15mm and 0.3mm in the structural design. In typical fourth- and fifth-generation mobile communication frequency bands, the increase in load capacitance due to the above factors... The magnitude is generally defined in the range of 0.X pF to several pF (0.X pF represents a few tenths of a pF).

[0045] S230, based on the increased load capacitance resulting from the aforementioned evolution of the physical environment, the equivalent lumped parameters of the antenna radiator feed port change. This distributed capacitance variable causes a change in the equivalent input reactance of the antenna radiator at the target operating frequency. The actual resonant frequency after introducing the capacitance variable... It evolved into the following form: ; Since the increase in load capacitance due to physical contact and displacement is always positive, according to the above expression, the actual resonant frequency is... It must be less than the initial resonant frequency. This means that a low-frequency shift phenomenon occurs.

[0046] This low-frequency offset phenomenon causes the input impedance of the antenna radiator to have a large reactance component at the original target operating frequency.

[0047] The results of this deduction not only verify the inevitability of the frequency offset phenomenon from a mathematical and logical perspective, but also provide clear technical guidance for the subsequent calculation of compensation reactance values ​​in the baseband processing unit.

[0048] The antenna's total input impedance can no longer satisfy the conjugate matching condition with the RF transceiver module, ultimately resulting in impedance mismatch and causing RF signal reflection loss. This mechanism analysis provides the physical basis for the subsequent acquisition and injection of corresponding compensation reactance values ​​in the system.

[0049] Based on the aforementioned physical antenna model, this embodiment further discloses the system's accurate digital recognition mechanism for button action states, as well as the multi-dimensional distribution path of internal terminal instructions.

[0050] When the system is idle or in a steady-state communication condition, it executes a press-before-determination and monitoring maintenance step. As a specific hardware interface implementation, in this embodiment, the baseband processing unit sets its internal general-purpose input / output interface to hardware interrupt monitoring mode. Based on the pull-up / pull-down resistor network settings of the microswitch's peripheral circuit, when the button logic signal is detected to remain in an initial high-impedance state without transition or a preset low level, the system determines that the side button assembly is in a free-space state in physical space.

[0051] In this baseline state, the baseband processing unit controls the adjustable impedance matching network to maintain the initial impedance matching parameters corresponding to this free space state and continues to sample the key logic signal pins at a continuous level. This pre-determination mechanism establishes the static operating reference of the RF system, preventing invalid topology flips in the impedance matching network when there is no external physical trigger.

[0052] Based on the aforementioned continuous monitoring state, the system possesses the physical basis for capturing transient triggering actions. When the internal metal contacts of the microswitch are pressed and closed, the voltage amplitude of the button logic signal exceeds a preset threshold voltage. The hardware interrupt controller within the baseband processing unit captures this level transition edge.

[0053] Based on the time-window debouncing logic established in the aforementioned embodiments, when the state identifier calculated internally by the system undergoes a valid transition from 0 to 1, the system accurately determines that the side button component has entered the pressed state. As the logical output of the state transition, this signal capture mechanism converts continuous analog mechanical displacement into a deterministic digital transition quantity that the processor can recognize, providing a trigger benchmark for subsequent RF parameter compensation scheduling.

[0054] After establishing the pressed state, the baseband processing unit executes cross-layer synchronous processing steps to achieve isolation and parallelism between upper-layer business logic and lower-layer physical tuning. Since the operating system's interface response time differs by orders of magnitude from the lower-layer RF network tuning time, this embodiment employs a priority-based bidirectional data stream dispatch mechanism to avoid RF compensation being blocked by upper-layer software processes.

[0055] Specifically, the baseband processing unit triggers interrupt dispatch within the same processing cycle that receives a valid level transition. As a software service control flow, the baseband processing unit sends the corresponding mechanical button interaction instructions to the upper-layer operating system through a regular interrupt request (IRQ), which then hands over the interface operation logic such as volume adjustment, screen wake-up, or power control to the operating system's input device subsystem.

[0056] As the underlying hardware control flow, the baseband processing unit issues pre-determined RF scheduling instructions to the underlying RF control bus via high-priority fast interrupt requests (FIQ) to synchronously drive physical RF matching compensation actions. For the underlying code operation mechanism of the operating system's input device subsystem in response to external interrupts, those skilled in the art can refer to existing mature mobile device operating system architectures.

[0057] To ensure the engineering reliability of the aforementioned cross-level synchronization processing steps and avoid transient loss of communication link lock due to instruction issuance delays, the system sets strict constraints on the execution timing of the underlying hardware radio frequency scheduling. The reference timestamp for the physical frequency offset caused by external mechanical pressure is set as follows: The actual timestamp of the baseband processing unit issuing scheduling commands to the RF control bus and triggering impedance network reconstruction is: .

[0058] To ensure signal continuity, this embodiment introduces a radio frequency compensation time tolerance window. The system must satisfy the following working condition alignment logic during instruction dispatch: ; In the formula, This characterizes the time lag from the system's perception of a press action to the actual activation of radio frequency compensation. An absolute value function is used to measure this time span. The maximum allowable radio frequency unlock time range is determined based on the data frame structure of the current communication standard. In a typical 5G New Radio (NR) communication scenario, The tolerance window The time alignment mechanism is typically set to be less than or equal to the length of a slot, i.e., between 0.5ms and 1ms. This mechanism avoids the mandatory requirements on the response time of the upper-layer software and ensures a high degree of alignment between the physical RF tuning action and the moment of physical pressing through a high-frequency interrupt channel. This prevents transient data packet loss caused by the antenna not being compensated for impedance in time when the user presses the button.

[0059] In one implementation, after clarifying the evolution of the physical environment caused by the pressing action, the system enters the RF impedance adaptive compensation algorithm and parameter acquisition process. To ensure stable operation of the communication equipment under complex electromagnetic interference and stringent timing constraints, this process is mainly executed through the following sub-steps: S310, based on transmission line theory and the equivalent model of lumped parameter networks, the resonant characteristics of the antenna are directly controlled by the imaginary part of the impedance (i.e., reactance) at the feed port. Combining the load capacitance increment determined in the preceding steps and the initial resonant frequency, the input impedance of the antenna radiator undergoes an objective drift when pressed.

[0060] In this embodiment, since the system operates precisely at the target resonant point in free space, the inductive and capacitive reactances inside the antenna cancel each other out. When an increment in the load capacitance is introduced, the system generates a residual change in equivalent input reactance at the original target resonant frequency. The scalar formula for calculating this change is expressed as follows: ; In this mathematical expression, due to the inherent capacitance of the physical antenna... In reality, they are typically distributed in the pF range, and the target resonant frequency... Generally, in the range of hundreds of MHz to several GHz, combined with a constant positive capacitance increment During the calculation process, the denominator term is always a real number greater than zero.

[0061] The equivalent input reactance change Physically, this shift manifests as a capacitive reactance. To restore the antenna radiator to the target operating frequency, a corresponding compensating reactance value must be introduced into the feed link. The algebraic relationship for its physical target orientation is as follows: ; In the formula, the negative sign indicates that the compensating impedance must have an inductive reactance property that corresponds to the capacitive reactance and cancels it out. This is an empirical fine-tuning factor for the parasitic parameters of the system traces, typically set between 0.95 and 1.05 based on the motherboard trace length during factory RF calibration. This compensation logic neutralizes excess distributed capacitive reactance caused by fingers approaching the metal motherboard by injecting additional inductive impedance.

[0062] In practical engineering, if the baseband processing unit performs high-precision complex impedance calculations in real time according to the aforementioned theoretical formula, it will consume a large amount of the main control chip's computing resources and exceed the time tolerance window set in the aforementioned cross-level scheduling. To overcome the computing power bottleneck and improve the system response rate, this embodiment adopts a hardware acceleration strategy using a preset mapping table. Specifically, the system obtains the compensation reactance value required to restore the antenna radiator to the target operating frequency by querying a preset impedance compensation lookup table.

[0063] As a preferred method, the impedance compensation lookup table is a multi-dimensional static data structure that is pre-calibrated and burned into the system's non-volatile memory before the terminal device leaves the factory. During the RF calibration stage before leaving the factory, the test instrument simulates various typical pressing displacement conditions in a microwave anechoic chamber, collects impedance offset samples corresponding to different pressing intensities, and records the calculated optimal compensation reactance value into the system.

[0064] During normal operation, when the baseband processing unit determines that the side button assembly is pressed, the system does not rely solely on a single voltage level for table lookup. Instead, it employs joint alignment logic based on multi-source state data. The system continuously acquires the active frequency band identifier of the current RF transceiver module. The baseband processing unit combines this active frequency band identifier with the current button logic state and inputs it as a joint index key into the impedance compensation lookup table.

[0065] The lookup table clearly records the level states of the key logic signals and the mapping relationship between different communication frequency bands and target compensation reactance values. Based on this structure, the system avoids secondary mismatches caused by sharing a single compensation parameter across the entire frequency band, and directly retrieves the compensation reactance value mapped to the current service condition from the impedance compensation lookup table.

[0066] After extracting the accurate compensation reactance value, the baseband processing unit needs to convert it into executable code that can be parsed by the underlying RF network. Since the adjustable impedance matching network consists of discrete RF switching devices and fixed-step arrays of inductors and capacitors, the theoretically calculated continuous compensation reactance value needs to be discretized and mapped to specific circuit switching combinations.

[0067] In this embodiment, the baseband processing unit employs minimum absolute value error decision logic to traverse all fixed impedance levels supported by the adjustable impedance matching network and retrieve the target matching topology parameter that has the smallest difference from the theoretical target value. This target matching topology parameter explicitly characterizes the on and off states of a specific switch pin in the impedance network array.

[0068] After determining the topology parameters, the baseband processing unit further encapsulates the data to generate an RF scheduling instruction containing the target matching topology parameters. The generation of this instruction signifies the completion of a closed loop from physical sensing to software control logic, laying the data foundation for subsequent physical transmission on the RF front-end control bus.

[0069] Based on the target RF scheduling instructions generated in the preceding steps, the system enters the low-level physical execution phase. This phase uses a standard hardware communication bus to transform the control logic in the digital domain into a physical topology reconstruction in the RF domain. To ensure low latency in scheduling and accurate tuning, this process specifically includes the following implementation steps.

[0070] S340, the baseband processing unit sends RF scheduling commands to the adjustable impedance matching network via the RF front-end control bus. In this embodiment, as a specific lower-level feature implementation of the underlying hardware bus, the system adopts the RF front-end control bus of the Mobile Industry Processor Interface (MIPIRFFE).

[0071] This bus establishes a serial communication link with microsecond-level response capability based on clock signal lines and bidirectional data signal lines. The baseband processing unit encapsulates the aforementioned RF scheduling instructions containing target matching topology parameters into a standard data frame structure.

[0072] The data frame includes the target device's slave address, internal register address, and payload data carrying topology settings. To ensure data transmission reliability in high-frequency electromagnetic interference environments, the system adds a parity check bit to the end of the frame structure for communication error detection.

[0073] After receiving and verifying the data frame, the control logic unit inside the adjustable impedance matching network extracts the target matching topology parameters and writes them into an internal temporary register for triggering physical actions. For the specific bit timing and handshake protocol of the underlying RF front-end control bus, those skilled in the art can refer to existing publicly available bus specifications.

[0074] After completing instruction parsing and data latching, the S350's adjustable impedance matching network performs hardware-level impedance network topology reconfiguration. As a preferred approach, the adjustable impedance matching network incorporates an array of radio frequency field-effect transistors (RF MOSFETs) manufactured using silicon-on-insulator (SOI) technology. This switch array, along with multiple chip inductors of varying inductance values, forms a distributed reconfigurable network.

[0075] To avoid the hot-switching effect that could damage SOI devices by directly switching the network topology during high-power RF transmission, this embodiment introduces a multi-dimensional joint alignment mechanism based on the transmit power state before the physical reconstruction operation occurs.

[0076] Specifically, the baseband processing unit acquires the current RF transmit power index in real time. If this power index exceeds the preset safe switching power threshold (which is typically set in the range of 10dBm to 15dBm in engineering), the system will trigger the power sag mechanism of the baseband transmit module within a microsecond time window. After completing the sag and ensuring that the feed link is in a low-power safe operating condition, the control logic unit outputs the corresponding drive bias voltage to control the conduction and cutoff of specific RF field-effect transistors. During this topology switching process, the control logic unit also strictly follows the smooth physical switching sequence of connecting before disconnecting to avoid transient open circuits in the feed link, thereby physically inserting or paralleling the inductor components corresponding to the target compensation reactance value into the antenna feed link. After the topology switch is completed, the system restores the original transmit power level.

[0077] Based on microwave network transmission theory, the degree of signal reflection at the antenna system's input port directly determines the efficiency of RF transmission and reception. Through the aforementioned physical topology reconstruction, the system alters the cascaded matching state of the RF link. The total input impedance at the antenna port after introducing the compensation network... With system characteristic impedance Together, they determine the total reflection coefficient of the reconstructed system. Its mathematical relationship satisfies the following calculation formula: ; In the formula, The system characteristic impedance preset for the RF transceiver module is typically a constant value of 50Ω in standardized microwave communication systems. Total input impedance. It is a complex superposition of the antenna's inherent impedance, the parasitic capacitive reactance introduced by pressing, and the compensating reactance injected by the impedance network.

[0078] because and In physical systems, all impedances are complex impedances containing a positive real part (i.e., unavoidable radiation resistance and ohmic loss). The denominator term in the above formula... The modulus is objectively greater than zero.

[0079] This underlying physical tuning action injects precise inductive compensation impedance to reduce the total input impedance under the pressed state. The system characteristic impedance is reapproximated on the complex plane of the Smith chart. This forces the total reflectance to The magnitude converges to zero, thereby eliminating the impedance mismatch and energy reflection phenomena caused by the aforementioned pressing action.

[0080] This embodiment focuses on disclosing the system recovery mechanism of the terminal device after the press interaction action ends.

[0081] After the user completes the physical pressing action and releases the insulated button, the mechanical physical space where the antenna radiator is located will undergo a reverse evolution. The movement of the external conductive medium such as the finger away and the mechanical rebound reset of the button body cause the previously introduced load capacitance increment to disappear. To prevent the impedance compensation parameters remaining in the underlying layer from causing new RF link mismatches, the system needs to perform strict rebound detection and physical topology reset actions, specifically including the following sub-steps: S410, during the continuous pressed state, the polling module inside the baseband processing unit continuously monitors the pin logic signal of the microswitch. Due to the inherent spatial electromagnetic coupling effect of the antenna radiator during radio frequency transmission, some radio frequency energy is intercepted and rectified by the peripheral traces of the microswitch, causing a transient high-level rise in the pin voltage. To avoid the risk of misjudgment caused by a single extreme level, in this embodiment, the system introduces a multi-source weighted detection mechanism based on a sliding time window.

[0082] The analog-to-digital converter module inside the baseband processing unit discretely samples the pin voltage at a preset sampling period and stores it in memory with a constant length. A sliding data window. The system calculates the confidence weights of sampling points within this window that meet the low-level threshold condition in real time. Its discrete summation formula is as follows: ; In the formula, This represents the total number of discrete sampling points contained within the sliding window. Due to limitations in physical storage resources and processing latency considerations, this value... The value is usually a positive integer between 16 and 32, which eliminates the mathematical singularity of zero denominator in division operations from the algorithm's underlying level. Let be the step decision function, when the... Second sampling voltage Output 1 if the voltage is below the preset release threshold, otherwise output 0.

[0083] This digital filtering algorithm quantifies the distribution stability of pin states. Through averaging, the system can tolerate and filter out the very few abnormal high-level glitches caused by transient radio frequency interference.

[0084] Combining the dual verification logic of time span and confidence level, the baseband processing unit calculates and outputs the reset status flag. Its Boolean logic expression is as follows: ; In the formula, The preset confidence threshold is usually set in the range of 0.85 to 0.95 based on actual anti-interference requirements, to ensure that the action is triggered only when the vast majority of sampling points are valid. It represents the total physical time span covered by the current sliding window. The release anti-shake time window is preset for the system. As the physical basis for extracting engineering parameters, the length of this anti-shake time window is usually set according to the inherent mechanical resonance characteristics of the beryllium copper metal spring, and is generally calibrated between 5ms and 15ms in typical terminal button structures.

[0085] The reset status flag is toggled from 0 to 1 if and only if the confidence level meets the threshold and the continuous duration is greater than or equal to the time window. This logic ensures that the system has a high degree of certainty in determining whether the side button assembly is completely disengaged from the pressed state.

[0086] S420, based on the aforementioned accurate bounce determination results, the equivalent lumped parameter network of the antenna radiator is restored to the previously described free-space state. In this physical scenario, if the underlying RF network still maintains the previous compensation state, the excess inductive compensation impedance in the feed link will break the original conjugate matching state because the additional load capacitance has dissipated with the physical reset.

[0087] This state objectively generates an equivalent reverse reactance mismatch, forcing the resonant frequency of the antenna system to shift abnormally towards higher frequencies. To suppress this reverse mismatch, the baseband processing unit triggers the reset logic of its internal state machine based on the flipped reset state flag.

[0088] As a preferred approach, the system further extracts the current communication frequency band identifier for lookup verification before generating the instruction. Subsequently, the baseband processing unit generates an RF reset instruction containing the initial matching topology parameters. This instruction explicitly points to the default impedance network pin settings of the system in free space state in its data structure.

[0089] S430, after generating the reset command, the baseband processing unit encapsulates the command again via the RF front-end control bus and sends it to the adjustable impedance matching network. Since the reset action is essentially a hard switching and removal of inductive components in the RF link, to ensure the physical safety of the devices, this embodiment synchronously executes the operating condition alignment logic with the RF transmit power state at this stage. If the baseband processing unit detects that it is currently in a high-power RF transmit state, the system will forcibly insert a microsecond-level transmit power sag sequence to actively reduce the voltage standing wave amplitude in the feed link.

[0090] After power sag alignment is completed, in order to avoid transient open circuits in the RF feed link caused by the moment compensation components are removed, which could lead to a surge in transient voltage standing wave ratio and damage to the front-end power amplifier, the control logic unit inside the adjustable impedance matching network adopts a smooth physical switching timing of connection first and then disconnection.

[0091] In practice, the system first outputs a bias voltage to turn on the basic matching link switch corresponding to the free space state, establishing a basic RF signal transmission channel. Within one microsecond of confirming the basic channel is on, the system then turns off the RF MOSFET used to introduce compensation reactance. Once the topology is fully reset, the system immediately removes the power sag and restores the target transmit power.

[0092] Through this underlying timing reconfiguration action, the system safely removes additional reactive components from the power supply link, ensuring that the impedance network topology smoothly and accurately reverts to its initial static matching state. This reset mechanism achieves a dynamic closed-loop impedance environment throughout the entire lifecycle of the button's physical interaction, improving the RF transceiver stability of the terminal device under continuous mechanical operation.

[0093] To further assist those skilled in the art in understanding the technical solution of the present invention, the following describes in detail the specific application embodiments of the present invention in conjunction with a specific 5G smartphone application scenario, and supplements relevant experimental verification and effect comparison data.

[0094] Specific application examples: In this application embodiment, the target terminal device is defined as one that supports the 5G New Radio (NR) N78 band (core operating frequency). A smartphone with a clock speed of GHz. The side volume control buttons of this phone are reused as the side button assembly of this invention.

[0095] When the device is in a free-space state where it is not touched, the antenna radiator exhibits an inherent equivalent capacitance. Approximately 2.5pF. At this point, the adjustable impedance matching network is in its default static setting, and the total input impedance at the antenna feed port is... Conjugate matching to system characteristic impedance (50 From the appendix Figure 3 As can be seen, at this point, corresponding to the free space reference curve, the system's reflection loss (S11 parameter) at the 3.5GHz frequency point is as low as -22dB, and the radio frequency energy is radiated outward with almost no loss.

[0096] When a user watches a high-resolution streaming video in landscape mode and presses the side button assembly to lower the volume, the physical environment changes abruptly. The insulated button body experiences an inward mechanical displacement of approximately 0.2 mm. Based on the physical mechanism disclosed in the foregoing embodiments, the finger's dielectric coupling (generating a first capacitance increment)... The reduction in the distance between the parallel plates of the buttons (generates a second capacitance increment) The combined effect of these factors injected a total of approximately 1.2 pF of load capacitance increment into the antenna system. .

[0097] If the system is not equipped with the compensation mechanism of this invention, the actual resonant frequency is calculated according to the aforementioned formula. The antenna's resonant point will shift sharply to lower frequencies, approximately 3.15 GHz. This is reflected in the attached... Figure 3 In the uncompensated press curve, the S11 parameter at the original target frequency of 3.5 GHz rapidly deteriorates to -3.5 dB. In engineering terms, this means that over 40% of the RF energy is bounced back to the power amplifier, resulting in severe impedance mismatch.

[0098] At the instant the aforementioned pressing action occurs, the underlying hardware interrupt mechanism of the baseband processing unit is activated. This is triggered when the button logic signal is detected to be continuously low for a specified period. Exceeding the preset mechanical image stabilization time window When the time is set to 12ms in this scenario, the system immediately determines that the system has entered the pressed state.

[0099] To curb the aforementioned mismatch trend, the baseband processing unit invokes the aforementioned impedance compensation algorithm. This is combined with the current 3.5GHz frequency band identifier and the calculated change in residual equivalent input reactance. The system is fine-tuning the coefficients. With the correction, the required injection point can be quickly located by looking up the table. Inductive compensation reactance (The equivalent physical device is a chip inductor of approximately 1.4 nH).

[0100] Given that the device is currently transmitting video data at high power (approximately 22dBm), to prevent the underlying hardware from being damaged by hot-switching, the baseband processing unit forcibly activates the transmit power sag mechanism simultaneously with issuing the MIPIRFFE RF scheduling command. Immediately afterwards, the SOI switch array within the adjustable impedance matching network precisely inserts the 1.4nH compensation inductor in a smooth, sequential connection-then-disconnection manner. Once the hardware reconfiguration is complete, the transmit power instantly recovers to 22dBm. The entire compensation process is strictly constrained within the preset RF compensation time tolerance window.

[0101] To quantitatively verify the engineering performance of the aforementioned adaptive tuning mechanism, this embodiment employs an Anritsu integrated testing system in conjunction with a three-dimensional electromagnetic radiation anechoic chamber turntable in a standard microwave anechoic chamber environment for comparative measurements. The specific results are as follows: After the adaptive compensation of this invention, the observation attachment Figure 3 The adaptive compensation curve in the figure. Injected compensation reactance. Subsequently, the magnitude of the total reflection coefficient at the antenna port converged back to zero. The originally offset resonant frequency was forcibly pulled back to the target frequency of 3.5 GHz. Actual measurement data shows that, under the pressed-and-held state, the S11 parameter at the target frequency was successfully repaired from -3.5 dB when it deteriorated to -18.5 dB, basically restoring to the ideal matching level in free space.

[0102] Appendix Figure 4 The lower half of the diagram shows the time-domain dynamic response of the total radiated power (TRP) during the test period. In the conventional uncompensated scheme (standard terminal), the TRP drops sharply by up to 5.8 dB due to severe impedance mismatch during button presses, and the error vector amplitude (EVM) deteriorates from 2.5% to 14%, directly causing video stream stuttering and data packet retransmission.

[0103] In contrast, the testing equipment (embodiment terminal) using the solution of this invention, at the time point of the pressing action triggering... Within 0.8 ms after the initial sag, the TRP exhibited only a tiny and extremely brief deep V-shaped sag (caused by a hardware-protected power sag actively executed by the system). Subsequently, the TRP curve rapidly recovered and stabilized at a high radiation level only 0.4 dB different from the free-space state, while the EVM remained stable below 3.0% throughout the process.

[0104] Based on the experimental verification data above, the solution of the present invention successfully transforms the static physical capacitance increment introduced by mechanical pressing into dynamic inductance compensation, eliminating the dead zone and disconnection pain point of handheld mobile terminal antenna in physical interaction within a millisecond-level closed loop.

Claims

1. A method for adding an antenna to a mobile phone button, applied in a terminal device including a mobile phone motherboard, a radio frequency transceiver module, an adjustable impedance matching network, and a side button assembly, wherein the side button assembly includes an insulated button body and a micro switch, the inner surface of the insulated button body is provided with a conductive pattern as an antenna radiator, and the antenna radiator is electrically connected to the radio frequency transceiver module via the adjustable impedance matching network, characterized in that... Includes the following steps: Real-time monitoring of the key logic signal output by the micro switch; When a level change is detected in the key logic signal, it is determined that the side key assembly is in a pressed state, and an RF scheduling command corresponding to the pressed state is generated. The adjustable impedance matching network is controlled by the radio frequency scheduling command to adjust the impedance network topology and compensate for the antenna resonant frequency shift caused by pressing the insulating button body.

2. The method for adding an antenna to a mobile phone button according to claim 1, characterized in that, The step of generating the radio frequency scheduling command corresponding to the pressed state specifically includes: Based on the preset load capacitance increment, the change in equivalent input reactance of the antenna radiator under the pressed state is determined; Based on the equivalent input reactance change, obtain the compensation reactance value required to restore the antenna radiator to the target operating frequency; Based on the compensation reactance value, the radio frequency scheduling instruction containing the target matching topology parameters is generated.

3. The method for adding an antenna to a mobile phone button according to claim 2, characterized in that, The preset value of the load capacitance increment constitutes the superposition value of the two physical effects triggered by the pressing action, namely the first capacitance increment and the second capacitance increment. Wherein, the first capacitance increment characterizes the effect generated when a human finger is attached to the outer side of the insulating button body. The finger surface tissue serves as a conductive medium and is separated from the inner antenna radiator by the insulating button body. Based on the medium coupling effect, the human body equivalent parasitic capacitance value is generated. The second capacitance increment characterizes the effect of the button structure displacement. When the insulated button body undergoes mechanical displacement into the terminal device, the antenna radiator approaches the mobile phone motherboard, and the distance between the plates of the two decreases. Based on the principle of parallel plate capacitor, the equivalent distributed capacitance value of the parallel plate is increased.

4. A method for adding an antenna to a mobile phone button according to claim 2, characterized in that, The step of obtaining the compensation reactance value required to restore the antenna radiator to the target operating frequency is specifically implemented by querying a preset impedance compensation lookup table, and includes: When it is determined that the side button assembly is in a pressed state, the current active frequency band identifier of the radio frequency transceiver module is obtained in real time, and the pre-established impedance compensation lookup table is accessed. The impedance compensation lookup table records the level state of the button logic signal and the mapping relationship between different communication frequency bands and the compensation reactance value. Based on the combined index key of the current voltage level and the operating frequency band identifier, the corresponding compensation reactance value is directly retrieved from the impedance compensation lookup table.

5. A method for adding an antenna to a mobile phone button according to claim 2, characterized in that, The step of controlling the adjustable impedance matching network to adjust the impedance network topology through the radio frequency scheduling command specifically includes: The adjustable impedance matching network parses the received radio frequency scheduling command and obtains the parsing result; Based on the analysis results, the radio frequency microelectromechanical switches or field-effect transistor arrays inside the adjustable impedance matching network are closed or opened to insert inductor or capacitor components corresponding to the compensation reactance values ​​into the feed link of the antenna radiator.

6. A method for adding an antenna to a mobile phone button according to claim 1, characterized in that, It also includes RF parameter recovery steps for mechanical reset actions, specifically including: The micro switch level is continuously polled. When the level of the button logic signal is detected to return to the initial state before the transition and the duration of the initial state meets the preset release debounce time window condition, the side button assembly is determined to bounce back and reset. A reset command is generated and sent to the adjustable impedance matching network; In response to the reset command, the adjustable impedance matching network removes the reactive components used for compensation and restores the impedance network topology to its free-space state before pressing.

7. A method for adding an antenna to a mobile phone button according to claim 2, characterized in that, When a level transition is detected in the key logic signal, the system also includes a cross-level synchronization processing step: Within the same processing cycle after receiving the level transition, the baseband processing unit on the mobile phone motherboard sends the corresponding mechanical button interaction command to the upper-layer operating system to execute the interface operation logic, and sends the RF scheduling command to the lower-layer RF control bus to synchronously execute the underlying physical RF matching compensation.

8. A method for adding an antenna to a mobile phone button according to claim 7, characterized in that, The specific steps for issuing the RF scheduling command to the underlying RF control bus are as follows: The baseband processing unit encapsulates the radio frequency scheduling instructions containing target matching topology parameters into a standard data frame structure; The data frame structure is transmitted in real time to the adjustable impedance matching network via the radio frequency front-end control bus of the mobile industry processor interface.

9. A method for adding an antenna to a mobile phone button according to claim 1, characterized in that, While the side button assembly is pressed and undergoes inward mechanical displacement, the antenna radiator maintains dynamic electrical conduction with the adjustable impedance matching network through an elastic conductive contact with deformation compensation capability.

10. A method for adding an antenna to a mobile phone button according to claim 1, characterized in that, It also includes a pre-press detection step: When the button logic signal is detected to be in an initial high impedance state without transition or a preset low level, it is determined that the side button assembly is in a free space state. The adjustable impedance matching network is controlled to maintain the initial impedance matching parameters corresponding to the free space state and to maintain the monitoring state of the button logic signal.

Images