Broadband high-precision standing wave detection circuit and method

Abstract

The invention belongs to the field of integrated circuit standing wave detection, and particularly relates to a broadband high-precision standing wave detection circuit and method. Comprising 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 is used for detecting voltage and current signals on a connecting wire of the power amplifier PA and the antenna, so that impedance measurement and standing wave detection can be realized; the 8-shaped inductor and the capacitor are connected in series for voltage division, and a detected voltage signal is output to the peak voltage detection module and the phase detection module and then is output to the signal measurement module; and the signal measurement module is used for measuring direct-current voltage data output by the peak voltage detection module and the phase detection module to prepare for subsequent measurement research. The method has the advantages that broadband detection of standing waves is realized, and common-mode voltage Vcm acquisition is added, so that the output result of standing wave detection is not affected by common-mode voltage, and high-precision detection is realized.

Description

Technical Field

[0001] The 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 essential to ensure effective signal transmission. Impedance mismatch can lead to power loss and reflected energy, affecting circuit performance. In the entire power radio frequency (RF) transmission system, the power amplifier is one of the components most sensitive to changes in standing wave ratio (VSWR). When an unmatched antenna load is connected to the output of the power amplifier, power reflection will occur, and in severe cases, the power amplifier may be permanently damaged. Therefore, it is necessary to protect the power amplifier by detecting the output standing wave. Once it is detected that the PA output is in an unmatched state, the standing wave detection circuit can output a corresponding control signal to adjust the output power of the PA, thereby protecting the PA and restoring the PA performance.

[0003] Real-time standing wave ratio detection and protection circuit are indispensable parts in the design of complete RF power amplifier circuit. At present, the real-time standing wave threshold detection circuit realized by logarithmic detector combined with directional coupler and corresponding control circuit simplifies the design process of actual circuit, but it cannot be integrated with chip, and it is difficult to realize accurate standing wave detection in broadband. Based on the above problems, this paper proposes a new broadband high-precision standing wave detection method and circuit, which directly detects the antenna load at the output end of PA by using the electromagnetic coupling between the figure-8 inductor and the output wire and the series voltage division of capacitor, and then obtains the standing wave ratio and the control signal for PA. The simulation results show that the scheme improves the detection accuracy and realizes accurate detection of standing waves in broadband. 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 for detecting a power amplifier PA with an antenna. 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 8-shaped 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 8-shaped 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, so as to realize 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 series voltage division;

[0008] The peak voltage detection module is connected to the signal measurement module, and the peak voltage detection module 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 respectively the output differential voltage signal of the figure-8 inductor in the figure-8 inductor signal acquisition module and the voltage signal after the series capacitor voltage division, and these two voltage signals are converted into differential square wave voltage signals and input into the mixer, and finally a DC differential voltage proportional to the phase difference is 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, in preparation 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 capacitors 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 common mode voltage V cm .

[0012] Furthermore, the 8-shaped center intersection position 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 position; 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 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 tube M1 through capacitive coupling;

[0017] The drain of the core NMOS tube M1 is connected to the power supply voltage VDD, the source of the core NMOS tube M1 is connected to the drain of the switch NMOS tube 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 tube M2, and the two are grounded together; the gate of the switch NMOS tube 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 tube M2 is a control tube, and its gate voltage controls the switch NMOS tube M2 to turn on and off, 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 proportional to the peak value of the voltage signal RF_IN on the upper plate of the capacitor Cpeak.

[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 the 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 the total DC voltage 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 also 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 With phase information Finally, the antenna standing wave ratio information is obtained, and the control signal for PA can be generated to achieve the protection and regulation of 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, which 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 of the workflow:

[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, and the impedance measurement and standing wave detection can be realized by detecting the voltage and current signals on the connecting wire between the power amplifier PA and the antenna;

[0037] The 8-shaped inductor signal acquisition module is to divide the voltage by connecting the 8-shaped inductor and the capacitors C1 and C2 in series, respectively 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;

[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 inductance signal acquisition module; there are four peak voltage detection modules in total, which output four voltage signals respectively, among which:

[0039] The output voltage signals V1 and V2 of the 8-shaped inductor, and the voltage signal V after the voltage division of the series capacitors C1 and C2 vdet , V1 and V2 extract their common mode voltage signal V through the RC 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 voltages V1, V2, V cm and V vdet and the DC differential voltage And carry out corresponding measurement statistics for backup.

[0042] In the present invention, the 8-shaped inductor signal acquisition module, peak voltage detection module, phase detection module, and signal measurement module are all integrated on a chip, which is a core circuit chip for standing wave detection; the power amplifier PA and its output matching network OMN can be integrated with the 8-shaped inductor signal acquisition module, peak voltage detection module, phase detection module, and signal measurement module on a 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 through a PCB and leads.

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

[0044] In the present invention, the 8-shaped inductor signal acquisition module is to respectively collect the current and voltage on the wire connecting the PA and the antenna through the 8-shaped inductor and the capacitor in series voltage division, and output a voltage signal related to the voltage and current on the wire; the magnetic coils of the 8-shaped inductor are symmetrically distributed on both sides of the long wire, and the current flowing through the long wire is collected and converted into a corresponding voltage through electromagnetic coupling with the long wire; if the PA and its matching network and the 8-shaped inductor signal acquisition module are integrated on a chip, the 8-shaped inductor can effectively offset the electromagnetic interference from the PA and its matching network, and under the same area, the 8-shaped 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, and achieves the purpose of standing wave detection, power amplifier protection and better output impedance matching through subsequent circuit processing; 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 realize the 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 a complete system architecture.

[0048] Figure 2 This is a schematic diagram of the 8-shaped 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 The following are the 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 detection results obtained by simulation are displayed 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 clearly understood, the present invention, in combination with the above description, actually builds the broadband high-precision standing wave detection circuit system on the 65nm CMOS process. The invention is further described in detail below 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 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, the peak voltage detection module, the phase detection module, and the signal measurement module are all integrated on one 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 connecting wire between the PA and the antenna. The overall architecture is as follows Figure 1 shown.

[0057] The 8-shaped signal acquisition module uses an 8-shaped inductor and capacitor in series to divide the voltage, respectively 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 8-shaped 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 8-shaped inductor can effectively offset the magnetic interference from the PA and its matching network. At the same time, under the same area, the 8-shaped 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 common mode voltage V cm Due to strong common-mode interference, Vcm cannot be ignored. The detected Vcm value is used in standing wave detection to eliminate the influence of common mode on 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 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 uses a source follower structure with a capacitor as the load to implement the peak detector, as shown in FIG. Figure 4 As shown, its input is the output voltage signal V1, V2, V cm With V vdet, these signals are coupled to the gate of M1 through capacitance. M1 is biased in the subthreshold region and periodically charges the source capacitance Cpeak, eventually obtaining a DC voltage proportional to the gate input peak value. M2 is a control tube. When the input is high level, the peak detector does not work, and starts to work when the voltage is low. Finally, the DC output voltage signal corresponding to each peak value is obtained at the output of the peak detector: 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: the input signals all pass through the balun, the function of the balun is to convert the single-ended input signal into a differential signal and suppress the common-mode component of the differential signal. The differential signal output by the balun will enter the limiter, which can further amplify the differential signal and put it into a large near-square wave. Finally, the differential signal close to the square wave drives the input of the mixer through a multi-stage driver. This paper proposes a complementary double-balanced mixer that can effectively suppress the phase shift caused by the asymmetry of the input signal. The output voltage is filtered by the RC parallel network to generate a DC signal proportional to the phase difference. Figure 5 is a schematic diagram of the phase detection module. Figure 6 The following are the 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 With 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 The antenna impedance Z is obtained L With 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 usually 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 technology, 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, 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 Its 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] So we can calculate

[0106] Γ=|Γ|e j∠Γ =0.514e -j25.98°

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

[0108] On the circle of 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 change condition of VSWR = 3:1. The simulation results show that the 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 may 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 should be granted 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 8-shaped 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 8-shaped 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, so as to realize 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 series voltage division; The peak voltage detection module is connected to the signal measurement module, and the peak voltage detection module 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 respectively the output differential voltage signal of the figure-8 inductor in the figure-8 inductor signal acquisition module and the voltage signal after the series capacitor voltage division, and these two voltage signals are converted into differential square wave voltage signals and input into the mixer, and finally a DC differential voltage proportional to the phase difference is 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 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 common mode voltage V cm .

3. The broadband high-precision standing wave detection circuit according to claim 2, characterized in that: The 8-shaped center intersection position 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 .

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 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.

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 tube M1 through capacitive coupling; The drain of the core NMOS tube M1 is connected to the power supply voltage VDD, the source of the core NMOS tube M1 is connected to the drain of the switch NMOS tube 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 tube M2, and the two are grounded together; the gate of the switch NMOS tube 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 tube M2 is a control tube, and its gate voltage controls the switch NMOS tube M2 to turn on and off, 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 proportional to the peak value of the voltage signal RF_IN on the upper plate of the capacitor Cpeak.

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 the 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 a DC voltage signal V 1_peak 、V 2_peak 、V cm_peak and V vdet_peak and the DC differential voltage Perform corresponding calculations to obtain the antenna impedance information Z L With 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 It can be calculated by the following formula: Among them, k L is a fixed proportional factor that can be 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 can be calibrated by 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 can be 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 8-shaped inductance signal acquisition module is integrated in 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 can be 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 is to divide the voltage by connecting the 8-shaped inductor and the capacitors C1 and C2 in series, respectively 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 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 inductance signal acquisition module; there are four peak voltage detection modules in total, which output four voltage signals respectively, among which: The output voltage signals V1 and V2 of the 8-shaped inductor, and the voltage signal V after the voltage division of the series capacitors C1 and C2 vdet , V1 and V2 extract their common mode voltage signal V through the RC 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 voltages V1, V2, V cm and V vdet and the DC differential voltage And carry out corresponding measurement statistics for backup.

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