A broadband high-precision standing wave detection circuit and method

Abstract

The present invention belongs to the field of integrated circuit standing wave detection, specifically a broadband high-precision standing wave detection circuit and method. It includes an 8-shaped inductor signal acquisition module, a peak voltage detection module, a phase detection module and a signal measurement module; the 8-shaped inductor signal acquisition module is used to detect the voltage and current signals on the connecting wire between the power amplifier PA and the antenna, so as to realize impedance measurement and standing wave detection; the 8-shaped inductor and capacitor are connected in series to divide the voltage, and the detected voltage signal is output to the peak voltage detection module and the phase detection module, and then output to the signal measurement module; the signal measurement module is used to measure the DC voltage data output by the peak voltage detection module and the phase detection module, in preparation for subsequent measurement research. The advantage of the present invention is that it realizes broadband detection of standing waves, while increasing the detection of common mode voltage V cm The output result of standing wave detection will not be affected by the common mode voltage, thus achieving high-precision detection.

Description

Technical Field

[0001] The present invention belongs to the technical field of integrated circuit standing wave detection, and in particular relates to a broadband high-precision standing wave detection circuit and method. Technical Background

[0002] In radio frequency (RF) transmission systems, impedance matching is crucial for ensuring efficient signal transmission. Impedance mismatches can lead to power loss and reflected energy, impacting circuit performance. Within the entire RF transmission system, the power amplifier (PA) is one of the components most sensitive to variations in the standing wave ratio (VSWR). When a mismatched antenna load is connected to the PA output, power reflections can occur, which can, in severe cases, permanently damage the PA. Therefore, output standing wave detection is necessary to protect the PA. Once a mismatch is detected at the PA output, the standing wave detection circuit outputs a corresponding control signal to adjust the PA's output power, protecting the PA and restoring its performance.

[0003] Real-time standing wave ratio (SWR) detection and protection circuits are essential components of a complete RF power amplifier (PA) circuit design. Currently, real-time standing wave threshold detection circuits, implemented using a logarithmic detector combined with a directional coupler and corresponding control circuits, simplify the actual circuit design process but cannot be integrated into a chip. Furthermore, accurate broadband standing wave detection is difficult to achieve. To address these issues, this paper proposes a new broadband, high-precision standing wave detection method and circuit. This method utilizes electromagnetic coupling between a figure-eight inductor and the output conductor, combined with voltage division via a series capacitor, to directly detect the antenna load at the PA output, thereby obtaining the standing wave ratio (SWR) and a control signal for the PA. Simulation results demonstrate that this approach improves detection accuracy and enables precise standing wave detection over a wide bandwidth. Summary of the Invention

[0004] The object of the present invention is to provide a broadband high-precision standing wave detection circuit and method with simple circuit structure and high detection accuracy.

[0005] The broadband high-precision standing wave detection circuit provided by the present invention is used to detect power amplifiers (PAs) with antennas. The standing wave detection circuit includes an 8-shaped inductance signal acquisition module, a peak voltage detection module, a phase detection module, and a signal measurement module.

[0006] The figure-8 inductance signal acquisition module is connected to the output end of the power amplifier PA, and the output end is connected to the antenna; the figure-8 inductance signal acquisition module is used to detect the voltage and current signals on the connecting wire between the power amplifier PA and the antenna, thereby realizing impedance measurement and standing wave detection;

[0007] The 8-shaped inductor signal acquisition module is connected to the peak voltage detection module and the phase detection module respectively, and outputs the detected voltage signal to the peak voltage detection module and the phase detection module through the 8-shaped inductor and capacitor in series voltage division;

[0008] The peak voltage detection module is connected to the signal measurement module, and is used to detect the peak voltage of the input radio frequency signal, process the received voltage signal, and output a DC voltage proportional to the peak voltage to the signal measurement module;

[0009] The phase detection module is also connected to the signal measurement module to detect the phase difference between the input signals and output a DC differential signal proportional to the phase difference to the signal measurement module. The input signals of the phase detection module are the output differential voltage signal of the figure-eight inductor in the figure-eight inductor signal acquisition module and the voltage signal after voltage division by the series capacitor. By converting these two voltage signals into differential square wave voltage signals and inputting them into the mixer, a DC differential voltage proportional to the phase difference is finally obtained and output to the signal measurement module.

[0010] The signal measurement module is used to measure the DC voltage data output by the peak voltage detection module and the phase detection module to prepare for subsequent measurement research.

[0011] In the present invention, the two output ports of the 8-shaped inductor of the 8-shaped inductor signal acquisition module are connected to the capacitor C det The two ports are connected through two sets of parallel resistors R cm With capacitor C cm connected in series; that is, the output port of the figure eight inductor adopts a capacitor C det The electromagnetically induced current is converted into voltage. After the conversion, the output voltages of the two ports are V1 and V2 respectively. The parallel resistor R cm With capacitor C cm The middle node takes the common mode voltage V cm .

[0012] Furthermore, the center intersection of the 8-shaped inductor is close to the connecting wire between the power amplifier PA and the antenna, and does not touch it; two capacitors C1 and C2 are connected in series on the connecting wire section between the 8-shaped inductor and the antenna; one end of C1 is directly connected to the connecting wire, and the other end of C2 is grounded; at the series connection between C1 and C2, the voltage at the connection is attenuated by voltage division, and the voltage V is collected. vdet .

[0013] In the present invention, the peak voltage detection module includes a peak detector core NMOS tube M1 and a switch NMOS tube M2;

[0014] There are four peak voltage detection modules, which respectively detect the four voltage signals RF_IN input through the figure eight inductor: voltage V1, V2, V cm and V vdet After conversion, four DC voltage signals PEAK_OUT corresponding to their respective peak values ​​are obtained: DC voltage V 1_peak 、V 2_peak 、V cm_peak and V vdet_peak , output to the signal measurement module.

[0015] Furthermore, the gate of M1 is connected to the bias voltage Vbias generated inside the peak voltage detection module through a resistor;

[0016] The voltage signal RF_IN is directly connected to the gate of the core NMOS transistor M1 through capacitive coupling;

[0017] The drain of the core NMOS transistor M1 is connected to the power supply voltage VDD, the source of the core NMOS transistor M1 is connected to the drain of the switch NMOS transistor M2 and the upper plate of the capacitor Cpeak, the lower plate of the capacitor Cpeak is connected to the source of the switch NMOS transistor M2, and the two are grounded together; the gate of the switch NMOS transistor M2 is connected to the control voltage (signal) Vctr generated inside the peak voltage detection module;

[0018] The output terminal of the peak voltage detection module for outputting the DC voltage signal PEAK_OUT is also connected to the source of M1;

[0019] The switch NMOS transistor M2 is a control transistor, and its gate voltage controls the on and off of the switch NMOS transistor M2 and controls whether the peak detector works. When Vctr is at a high level, the detector does not work; when it is at a low level, the detector works. When Vctr is at a low level, the voltage signal RF_IN controls M1 to charge the capacitor Cpeak, and finally generates a DC voltage on the upper plate of the capacitor Cpeak that is proportional to the peak value of the voltage signal RF_IN.

[0020] In the present invention, the phase detection module includes a balun, a limiter and a mixer; the voltages V1, V2, V vdet The differential square wave signal is amplified by the balun and limiter and sent to the mixer. The mixer compares the phase difference of the input differential square wave signal and generates a DC differential signal proportional to the phase difference on the resistor and capacitor, that is, a DC differential voltage.

[0021] In the present invention, the figure-8 inductance signal acquisition module may also be integrated into the power amplifier PA.

[0022] In the present invention, the signal measurement module can measure all DC voltages V 1_peak 、V 2_peak 、V cm_peak 、V vdet_peak and DC differential voltage To measure, you can use a multimeter to measure the DC voltage.

[0023] In the present invention, according to different application requirements, the signal measurement module further includes a DC signal processor to output a DC voltage signal V 1_peak 、V 2_peak 、V cm_peak 、V vdet_peak and Perform corresponding calculations to obtain the antenna impedance information Z L and phase information Finally, the antenna standing wave ratio information is obtained, and the control signal for the PA can be generated to achieve protection and regulation of the PA; the specific process of the corresponding calculation method of the DC voltage signal is as follows:

[0024] V 1_am =V 1_peak -V TH

[0025] V 2_am =V 2_peak -V TH

[0026] V cm_am =V cm_peak -V TH

[0027] V vdet_am =V vdet_peak -V TH

[0028] Among them, V TH is the threshold voltage of the NMOS tube M1 under the current process, which is a known fixed value;

[0029] Antenna impedance information Z L It can be calculated by the following formula:

[0030]

[0031] Among them, k L is a fixed proportional factor that can be calibrated by one or more known antenna impedances; V 1_am 、V 2_am 、V cm_am 、V vdet_am As an intermediate parameter in the calculation process;

[0032] Phase information of impedance The calculation process is as follows:

[0033]

[0034] in, is a fixed proportional factor that can be calibrated by one or more known antenna impedances.

[0035] The detection method of the broadband high-precision standing wave detection circuit provided by the present invention has the following specific steps:

[0036] When working, the 8-shaped inductance signal acquisition module of the standing wave detection circuit is directly connected to the output of the power amplifier PA. By detecting the voltage and current signals on the connecting wire between the power amplifier PA and the antenna, impedance measurement and standing wave detection can be achieved;

[0037] The 8-shaped inductor signal acquisition module collects the current and voltage on the wire connecting the PA and the antenna through the 8-shaped inductor and capacitors C1 and C2 in series to divide the voltage, and outputs a voltage signal related to the voltage and current on the wire;

[0038] The peak voltage detection module is used to detect the peak value of the input RF signal and output a DC voltage proportional to the peak voltage. The input of the peak detection module is the output voltage signal of the 8-shaped inductor signal acquisition module. There are four peak voltage detection modules in total, each outputting four voltage signals:

[0039] The output voltage signals V1 and V2 of the 8-shaped inductor, and the voltage signal V after the voltage is divided by the series capacitors C1 and C2 vdet , V1 and V2 extract their common mode voltage signal V through the resistor-capacitor network cm ;

[0040] The phase detection module is used to detect the phase difference between the input signals and output a DC differential voltage signal proportional to the phase difference. Among them, the phase detection module has two groups of input signals, one group is the output voltage signals V1 and V2 of the 8-shaped inductor, and the other group is the voltage signal V after the series capacitors C1 and C2 divide the voltage. vdet By converting these two sets of voltage signals into differential square wave voltage signals and inputting them into the mixer, a DC differential voltage signal proportional to the phase difference is finally obtained.

[0041] The signal measurement module is responsible for collecting the output DC voltage V1, V2, V cm and V vdet and DC differential voltage And carry out corresponding measurement statistics for backup.

[0042] In the present invention, the figure-eight inductor signal acquisition module, peak voltage detection module, phase detection module, and signal measurement module are all integrated on a single chip, which serves as the core circuit chip for standing wave detection. The power amplifier PA and its output matching network OMN can be integrated with the figure-eight inductor signal acquisition module, peak voltage detection module, phase detection module, and signal measurement module on a single chip, or can be used as a separate chip or device to be tested and connected to the core circuit chip for standing wave detection via a PCB and leads.

[0043] The present invention realizes full decoupling of the standing wave detection circuit, the PA and its matching network.

[0044] In the present invention, the figure-eight inductor signal acquisition module uses a figure-eight inductor and a capacitor in series to divide the voltage, respectively, to collect the current and voltage on the wire connecting the PA and the antenna, and output a voltage signal related to the voltage and current on the wire. The magnetic coils of the figure-eight inductor are symmetrically distributed on both sides of the long wire. Through electromagnetic coupling with the long wire, the current flowing through the long wire is collected and converted into a corresponding voltage. If the PA, its matching network, and the figure-eight inductor signal acquisition module are integrated on a single chip, the figure-eight inductor can effectively offset the electromagnetic interference from the PA and its matching network. Under the same area, the figure-eight inductor has a higher current gain.

[0045] In addition, the 8-shaped inductor collects the current on the wire through electromagnetic coupling and converts it into the corresponding voltage through the capacitor Cdet on the port: V1 and V2. V1 and V2 are extracted to their common mode voltage V through the resistor-capacitor network. cm ; Capacitors C1 and C2 are connected in series to divide the voltage on the wire and then collect the voltage to get the voltage V vdet Compared with the traditional coupled inductor which only collects V1 and V2, the present invention collects the common mode voltage V on this basis. cm And participate in subsequent processing to eliminate the influence of common mode voltage on detection.

[0046] The present invention utilizes the electromagnetic coupling between the figure-8 inductor and the output conductor to collect the antenna current and voltage. Through subsequent circuit processing, it achieves the purpose of standing wave detection, power amplifier protection and better output impedance matching. The differential voltage and common mode voltage of the output port of the figure-8 inductor are synchronously collected, so that the detection method can effectively suppress the common mode voltage. The capacitor is used as the load of the figure-8 inductor to achieve the functions of current-to-voltage conversion, 90° phase shift and filtering. The advantages of the present invention are that it realizes broadband detection of standing waves and increases the common mode voltage V cm The output result of standing wave detection will not be affected by the common mode voltage, thus achieving high-precision detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a broadband high-precision standing wave detection method and complete system architecture.

[0048] Figure 2 This is a schematic diagram of the figure-8 inductance signal acquisition module.

[0049] Figure 3 Schematic diagram of the peak voltage detection module.

[0050] Figure 4 The figure shows the specific circuit diagram and simulation results of the peak voltage detection module implemented in 65nm CMOS process.

[0051] Figure 5 Schematic diagram of the phase detection module.

[0052] Figure 6 Specific simulation results of the phase detection module implemented in 65nm CMOS process.

[0053] Figure 7 The amplitude error and phase error of the detected reflection coefficient Γ are obtained through simulation under the impedance change condition of VSWR=3:1.

[0054] Figure 8 The figure shows the detection results obtained by simulation on the Smith circle under the impedance change condition of VSWR=3:1. DETAILED DESCRIPTION

[0055] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention, in combination with the above description, actually builds this broadband high-precision standing wave detection circuit system on the 65nm CMOS process. The following is a further detailed description of the invention in combination with this specific example and with reference to the accompanying drawings.

[0056] A broadband, high-precision standing wave detection method and circuit. It mainly includes an 8-shaped inductance signal acquisition module, a peak voltage detection module, a phase detection module, and a signal measurement module. The 8-shaped inductance signal acquisition module, the peak voltage detection module, the phase detection module, and the signal measurement module are all integrated on a chip, which is the core circuit chip for standing wave detection. This solution fully decouples the standing wave detection method and circuit from the power amplifier PA and its matching network. When working, the standing wave detection circuit is directly connected to the output of the PA, and impedance measurement and standing wave detection can be achieved by detecting the voltage and current signals on the wire connecting the PA and the antenna. The overall architecture is as follows Figure 1 shown.

[0057] The figure-8 signal acquisition module uses a figure-8 inductor and a capacitor in series to divide the voltage, respectively, to collect the current and voltage on the wire connecting the PA and the antenna, and output a voltage signal related to the voltage and current on the wire. The magnetic coils of the figure-8 inductor are symmetrically distributed on both sides of the long wire. Through electromagnetic coupling with the long wire, the current flowing through the long wire is collected and converted into a corresponding voltage. If the PA and its matching network and the signal acquisition module are integrated on a chip, the figure-8 inductor can effectively offset the magnetic interference from the PA and its matching network. At the same time, under the same area, the figure-8 inductor has a higher current gain.

[0058] In this example, the area of ​​the 8-shaped coil is 200um×270um, the Q value is 10, and the coupling coefficient k with the wire is 0.4. The 8-shaped inductor collects the current on the wire through electromagnetic coupling and converts it into corresponding voltages V1 and V2 through the capacitor Cdet on the port. This capacitor has three functions here: IV conversion, 90° phase shifter and filtering. The two ports are then connected through two parallel resistors R cm Capacitor C cm connected in series and in parallel with the resistor R cm With capacitor C cm The middle node takes the common mode voltage V cm Due to strong common-mode interference, Vcm cannot be ignored. The detected Vcm value is used in the standing wave detection to eliminate the influence of the common mode on the detection. In this example, the capacitance Cdet is 3pF, R cm with C cm The values ​​of are 12KΩ and 25fF respectively. The voltage divider capacitors C1 and C2 are connected in series to attenuate the voltage on the wire and collect the voltage to get the voltage V vdet In this example, the sizes of C1 and C2 are 60fF and 300fF respectively. Compared with the traditional coupled inductor which only collects V1 and V2, this solution collects the common mode voltage Vcm on this basis and participates in subsequent processing, which can eliminate the influence of the common mode voltage on the detection. Figure 2 shown.

[0059] The peak voltage detection module is used to detect the peak value of the input RF signal and output a DC voltage proportional to the peak voltage. The input of the peak detection module is the output voltage signal of the 8-shaped inductor signal acquisition module. The module block diagram is as follows: Figure 3 In the 65nm CMOS process, the present invention adopts a source follower structure with a capacitor as the load to realize the peak detector, as shown in FIG. Figure 4 As shown, its input is the output voltage signal V1, V2, V cm With V vdetThese signals are coupled to the gate of M1 through capacitance. M1 is biased in the subthreshold region and periodically charges the source capacitance Cpeak, ultimately obtaining a DC voltage proportional to the gate input peak value. M2 is the control tube. When the input is high, the peak detector does not work, and starts working when the voltage is low. Finally, the output of the peak detector obtains a DC output voltage signal corresponding to each peak value: V 1_peak 、V 2_peak 、V cm_peak 、V vdet_peak and

[0060] The phase detection module is used to detect the phase difference between the input signals and output a DC differential signal proportional to the phase difference. The input signals of the phase detection module are the output differential voltage signal V1-V2 of the 8-digit inductor in the signal acquisition module and the voltage signal after the series capacitor voltage division. Vvdet By converting these two voltage signals into differential square wave voltage signals and inputting them into the mixer, a DC differential signal proportional to the phase difference is finally obtained. The specific implementation method is as follows: All input signals pass through a balun, which converts single-ended input signals to differential signals and suppresses the common-mode component of the differential signal. The differential signal output by the balun enters a limiter, which further amplifies the differential signal to a near-square wave. The resulting near-square wave differential signal passes through a multi-stage driver and drives the mixer input. This paper proposes a complementary double-balanced mixer that effectively suppresses phase shift caused by input signal asymmetry. The output voltage is filtered by a parallel RC network, generating a DC signal proportional to the phase difference. Figure 5 is a schematic diagram of the phase detection module. Figure 6 Specific simulation results of the phase detection module implemented in 65nm CMOS process.

[0061] The signal measurement module is responsible for collecting the output DC voltage signal and performing corresponding processing and calculation to obtain the antenna impedance information Z L and phase information Finally, the standing wave ratio information is obtained. The DC voltage V 1_peak 、V 2_peak 、V cm_peak 、V vdet_peak and Get the antenna impedance Z L and phase information The calculation process is as follows:

[0062] V 1_am =V 1_peak -V TH

[0063] V 2_am =V 2_peak -V TH

[0064] V cm_am =V cm_peak -V TH

[0065] V vdet_am =V vdet_peak -V TH

[0066] Among them, V TH is the threshold voltage of the NMOS tube M1 under the current process, which is a known fixed value.

[0067] Then the antenna impedance can be calculated as follows:

[0068]

[0069] Among them, K L is a fixed proportional factor that can be calibrated by one or more known antenna impedances.

[0070] Phase information of impedance The calculation process is as follows:

[0071]

[0072] in, is a fixed proportional factor that can be calibrated by one or more known antenna impedances.

[0073] After obtaining the antenna impedance information, the calculation process of the antenna standing wave ratio information Γ is as follows:

[0074]

[0075] Where Z0 is the nominal antenna impedance, which is typically 50Ω;

[0076] Since Γ is a complex number, it can be defined as:

[0077] Γ=|Γ|e j∠Γ .

[0078] In order to make the present invention more detailed, a simulation example is given to further illustrate the above algorithm:

[0079] Using TSMC 65nm process, the above simulation is performed at a center frequency of 2.4G, and the calibrated antenna impedance is designed to be

[0080]

[0081] This impedance is a point on VSWR=3. When the output impedance is this impedance, the data size obtained is:

[0082] V 1_peak =487mV

[0083] V 2_peak =392.6mV

[0084] V cm_peak =401.7mV

[0085] V vdet_peak =633mV

[0086]

[0087] Under this process, V TH =320mV, put it into the above expression, and we can get the sizes of the two key parameters:

[0088] K L =28.8Ω

[0089]

[0090] Through the above two parameters, the impedance value under other impedance conditions can be calculated by measurement:

[0091] For example, when the simulated impedance becomes The corresponding Γ=|Γ|e j∠Γ =0.5e -j24° ,

[0092] In this case, the simulation data are:

[0093] V 1_peak =461mV

[0094] V 2_peak =395mV

[0095] V cm_peak =405mV

[0096] V vdet_peak =648mV

[0097]

[0098] Substitute the following formula: V 1_AM =V 1_peak -V TH

[0099] V 2_AM =V 2_peak -VTH

[0100] V cm_AM =V cm_peak -V TH

[0101] V vdet_AM =V vdet_peak -V TH

[0102]

[0103] get

[0104]

[0105] Thus, we can calculate

[0106] Γ=|Γ|e j∠Γ =0.514e -j25.98°

[0107] The errors in Γ amplitude and phase measurement are 0.014 and 1.98°, respectively.

[0108] On the circle with VSWR=3, 18 impedance points were selected and tested using the above process. Figure 7 The amplitude error and phase error of the reflection coefficient Γ are shown respectively, Figure 8 The figure shows the detection results on the Smith circle under the impedance variation condition of VSWR = 3:1. The simulation results show that this detection method has high accuracy.

[0109] Although the above methods are illustrated and described as a series of structures for simplicity of explanation, it should be understood and appreciated that these methods are not specifically limited because according to one or more embodiments, some structures can occur in different orders and / or concurrently with other actions from those illustrated and described herein or not illustrated and described herein but understandable to those skilled in the art.

[0110] The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A broadband high-precision standing wave detection circuit for detecting a power amplifier PA with an antenna, characterized in that: The standing wave detection circuit includes an 8-shaped inductance signal acquisition module, a peak voltage detection module, a phase detection module and a signal measurement module; The figure-8 inductance signal acquisition module is connected to the output end of the power amplifier PA, and the output end is connected to the antenna; the figure-8 inductance signal acquisition module is used to detect the voltage and current signals on the connecting wire between the power amplifier PA and the antenna, thereby realizing impedance measurement and standing wave detection; The 8-shaped inductor signal acquisition module is connected to the peak voltage detection module and the phase detection module respectively, and outputs the detected voltage signal to the peak voltage detection module and the phase detection module through the 8-shaped inductor and capacitor in series voltage division; The peak voltage detection module is connected to the signal measurement module, and is used to detect the peak voltage of the input radio frequency signal, process the received voltage signal, and output a DC voltage proportional to the peak voltage to the signal measurement module; The phase detection module is also connected to the signal measurement module to detect the phase difference between the input signals and output a DC differential signal proportional to the phase difference to the signal measurement module. The input signals of the phase detection module are the output differential voltage signal of the figure-eight inductor in the figure-eight inductor signal acquisition module and the voltage signal after voltage division by the series capacitor. By converting these two voltage signals into differential square wave voltage signals and inputting them into the mixer, a DC differential voltage proportional to the phase difference is finally obtained and output to the signal measurement module. The signal measurement module is used to measure the DC voltage data output by the peak voltage detection module and the phase detection module.

2. The broadband high-precision standing wave detection circuit according to claim 1, characterized in that: The two output ports of the 8-shaped inductor of the 8-shaped inductor signal acquisition module are connected to the capacitor C det The two ports are connected in parallel through two resistors R cm With capacitor C cm connected in series; that is, the output port of the 8-shaped inductor adopts a capacitor C det The electromagnetically induced current is converted into voltage. After the conversion, the output voltages of the two ports are V1 and V2 respectively. The parallel resistor R cm With capacitor C cm The middle node takes the common mode voltage V cm .

3. The broadband high-precision standing wave detection circuit according to claim 2, characterized in that: The center intersection of the figure-8 inductor is close to the connecting wire between the power amplifier PA and the antenna, but does not touch it. Two capacitors C1 and C2 are connected in series on the connecting wire section between the figure-8 inductor and the antenna. One end of C1 is directly connected to the connecting wire, and the other end of C2 is grounded. At the series connection between C1 and C2, the voltage at the connection is attenuated by voltage division, and the voltage V is collected. vdet .

4. The broadband high-precision standing wave detection circuit according to claim 3, characterized in that: The peak voltage detection module includes a peak detector core NMOS tube M1 and a switch NMOS tube M2; There are four peak voltage detection modules, which respectively detect the four voltage signals RF_IN input through the 8-shaped inductor: voltage V1, V2, V cm and V vdet After conversion, four DC voltage signals PEAK_OUT corresponding to their respective peak values ​​are obtained: DC voltage V 1_peak 、V 2_peak 、V cm_peak and V vdet_peak , output to the signal measurement module.

5. The broadband high-precision standing wave detection circuit according to claim 4, characterized in that: The gate of M1 is connected to the bias voltage Vbias generated inside the peak voltage detection module through a resistor; The voltage signal RF_IN is directly connected to the gate of the core NMOS transistor M1 through capacitive coupling; The drain of the core NMOS transistor M1 is connected to the power supply voltage VDD, the source of the core NMOS transistor M1 is connected to the drain of the switch NMOS transistor M2 and the upper plate of the capacitor Cpeak, the lower plate of the capacitor Cpeak is connected to the source of the switch NMOS transistor M2, and the two are grounded together; the gate of the switch NMOS transistor M2 is connected to the control voltage Vctr generated inside the peak voltage detection module; The output terminal of the output DC voltage signal PEAK_OUT of the peak voltage detection module is also connected to the source of M1; The switch NMOS transistor M2 is a control transistor, and its gate voltage controls the on and off of the switch NMOS transistor M2 and controls whether the peak detector works. When Vctr is at a high level, the detector does not work; when it is at a low level, the detector works. When Vctr is at a low level, the voltage signal RF_IN controls M1 to charge the capacitor Cpeak, and finally generates a DC voltage on the upper plate of the capacitor Cpeak that is proportional to the peak value of the voltage signal RF_IN.

6. The broadband high-precision standing wave detection circuit according to claim 5, characterized in that: The phase detection module includes a balun, a limiter and a mixer; the voltages V1, V2, V vdet The differential square wave signal is amplified by the balun and limiter and sent to the mixer. The mixer compares the phase difference of the input differential square wave signal and generates a DC differential signal proportional to the phase difference on the resistor and capacitor, that is, a DC differential voltage.

7. The broadband high-precision standing wave detection circuit according to claim 6, characterized in that: According to different application requirements, the signal measurement module also includes a DC signal processor to output the DC voltage signal V 1_peak 、V 2_peak 、V cm_peak and V vdet_peak and DC differential voltage Perform corresponding calculations to obtain the antenna impedance information Z L and phase information Finally, the antenna standing wave ratio information is obtained; the specific process of the corresponding calculation method of the DC voltage signal is as follows: V 1_am =V 1_peak -V TH V 2_am =V 2_peak -V TH V cm_am =V cm_peak -V TH V vdet_am =V vdet_peak -V TH Among them, V TH is the threshold voltage of the NMOS tube M1 under the current process, which is a known fixed value; Antenna impedance information Z L Calculated by the following formula: Among them, k L is a fixed proportional factor that is calibrated by one or more known antenna impedances; Phase information of impedance The calculation process is as follows: in, is a fixed proportional factor that is calibrated using one or more known antenna impedances.

8. The broadband high-precision standing wave detection circuit according to claim 7, characterized in that: Get the antenna impedance information Z L Afterwards, the calculation process of the antenna standing wave ratio information Γ is as follows: Where Z0 is the nominal antenna impedance; Since Γ is a complex number, it is defined as: C=|C|e j∠Γ 。 9. The broadband high-precision standing wave detection circuit according to any one of claims 1 to 8, characterized in that: The figure-8 inductance signal acquisition module is integrated into the power amplifier PA.

10. The detection method of a broadband high-precision standing wave detection circuit according to any one of claims 1 to 8, characterized in that: The specific steps of the workflow are as follows: When working, the 8-shaped inductance signal acquisition module of the standing wave detection circuit is directly connected to the output of the power amplifier PA, and the impedance measurement and standing wave detection are realized by detecting the voltage and current signals on the connecting wire between the power amplifier PA and the antenna; The 8-shaped inductor signal acquisition module collects the current and voltage on the wire connecting the PA and the antenna through the 8-shaped inductor and capacitors C1 and C2 in series to divide the voltage, and outputs a voltage signal related to the voltage and current on the wire; The peak voltage detection module is used to detect the peak value of the input RF signal and output a DC voltage proportional to the peak voltage. The input of the peak detection module is the output voltage signal of the 8-shaped inductor signal acquisition module. There are four peak voltage detection modules in total, each outputting four voltage signals: The output voltage signals V1 and V2 of the 8-shaped inductor, and the voltage signal V after the voltage is divided by the series capacitors C1 and C2 vdet , V1 and V2 extract their common mode voltage signal V through the resistor-capacitor network cm ; The phase detection module is used to detect the phase difference between the input signals and output a DC differential voltage signal proportional to the phase difference. Among them, the phase detection module has two groups of input signals, one group is the output voltage signals V1 and V2 of the 8-shaped inductor, and the other group is the voltage signal V after the series capacitors C1 and C2 divide the voltage. vdet By converting these two sets of voltage signals into differential square wave voltage signals and inputting them into the mixer, a DC differential voltage signal proportional to the phase difference is finally obtained. The signal measurement module is responsible for collecting the output DC voltage V1, V2, V cm and V vdet and DC differential voltage And carry out corresponding measurement statistics for backup.

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