WO2011088647A1

WO2011088647A1 - Device and method for impedance matching

Info

Publication number: WO2011088647A1
Application number: PCT/CN2010/072807
Authority: WO
Inventors: 周占荣; 丁国林
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-01-25
Filing date: 2010-05-14
Publication date: 2011-07-28
Also published as: CN101800561B; CN101800561A

Abstract

A device and a method for impedance matching are disclosed. According to reflected signal intensity S_N and power P_n of a radio power amplifier, the control voltage of equivalent impedance is adjusted through a corresponding judging condition, thereby adaptive matching is realized between the radio power amplifier and a matching object. Utilizing the device and the method, designing of an adaptive matching circuit is simplified, the period of handset designing and debugging is shortened, the practical applicability of the adaptive matching circuit is improved, and the quality of handset calling is enhanced, and the stability and linearity of the radio power amplifier and the radio performance index of the complete handset are improved completely.

Description

Impedance matching device and method

The present invention relates to impedance matching techniques, and more particularly to an adaptive impedance matching apparatus and method. Background technique

In the development of mobile terminals such as mobile phones, usually one model corresponds to one antenna, which makes the antenna design work increase, the development cycle of the mobile terminal is lengthened, labor cost and a large amount of experimental resources are wasted.

In the process of frequently using a mobile phone, various communication failures are often encountered, such as: when using a mobile phone call, changes in the call site, changes in the position and posture of the mobile phone, etc., may result in poor call quality. This is because the input impedance of the actually used antenna is not a fixed value, and depends to a considerable extent on the surrounding environment. Therefore, when the environment of the mobile phone changes, the impedance of the mobile phone antenna changes, so that the mobile phone and the mobile phone The antennas no longer match exactly.

In the existing equipment, when static impedance matching is usually used, in the actual environment, the matching network mismatch between the RF power amplifier output on the mobile phone main board and the antenna will be caused, and part of the power will be reflected from the antenna back to the power amplifier. Some of the power reflected back can no longer be used as the transmit power, which leads to a decrease in the efficiency of the power supply, and may also cause deterioration of the radio frequency index. More seriously, if the proportion of the backscatter power is too large, it will be reflected. This causes the circuit to oscillate, causing the radio connection to eventually break.

To solve the above problems, it is necessary to design an adaptive impedance matching circuit, so that the mobile phone motherboard can adapt to any mobile phone antenna in the same frequency band, thereby improving the efficiency of the antenna and shortening the development cycle of the mobile phone. For the problem of adaptive impedance matching, many experts at home and abroad have done related research work, but they are not widely used in mobile phone circuits at present, and there are only some simple adaptive impedance matching control circuits. Here are a few typical patents currently studied at home and abroad: Patent No. CN03817073.6 is a Chinese patent for dynamic impedance matching between a power amplifier and an antenna. It has a circulator and a controllable matching network. The circulator will receive from the power amplifier at the first port. The incoming signal is sent to the antenna via the second port, and the signal reflected at the antenna and received at the second port is diverted through the third port; the key is: a directional coupler causes the signal from the power amplifier to travel to the antenna to turn To the signal detector, the amplitude and phase of the signal can be derived from the partial signal; the circulator routes the entire signal reflected by the antenna to the signal detector; the disadvantage of this dynamic impedance matching device is that the dynamic matching time is relatively long and the structure is relatively quite complicated.

Japanese Patent Laid-Open No. Hei 8-97733 discloses an impedance matching device capable of automatically matching the impedance between an antenna and a transmitting portion in the case where the environment around the antenna is suddenly changed. The conventional impedance matching device disclosed in the patent is provided with: a standing wave ratio detecting portion for measuring a plurality of voltages at respective points on a transmission path from a transmitting portion to an antenna to detect a standing wave ratio; an impedance calculating portion, And configured to calculate a current impedance of the antenna side viewed from a side of the transmission path according to the VSWR on the transmission path; and set a matching table for storing in a list form as a match to eliminate the impedance of the transmitting part side a set value of a predetermined component that is different from the calculated current impedance; a variable matching portion for impedance adjustment in an input end of the antenna that receives the transmission power from the transmission path; and an operation control portion for using the current impedance And the above-described setting matching table is used to control the matching elements of the variable matching portion to be predetermined values. As described above, the conventional impedance matching device disclosed in the patent adjusts the variable matching circuit while storing the set value of the predetermined component which is matched to eliminate the difference between the impedance of the transmitting portion side and the current impedance of the antenna side. To provide this setting, and to match the impedance between the transmitting part and the antenna; however, the disadvantage of the impedance matching device is that the link is complicated and the cost is too high, and it is not feasible to use in the mobile phone.

The Chinese patent of CN1957538A discloses a mobile wireless device capable of adaptive impedance matching, and the matching detecting portion includes an impedance matching ratio between the detecting antenna and the signal processing portion, a signal strength detecting portion, and a reflected voltage detecting portion. By using the fastest speed The drop algorithm adjusts the matching load value. The program needs to obtain a large number of experiments to obtain the initial value of the matching load of different working states of the mobile phone. In the patent, the initial chromosome is stored as experience. The biggest breakthrough is to use the chromosome scheme to solve the problem that the matching adjustment time is too long. Make the adaptive impedance matching circuit more practical. However, the circuit design of the mobile wireless device is complicated and difficult to implement.

In the prior art, since the above-mentioned circuit requires manual or mechanical adjustment, the dynamic matching time is too long, so that it does not have a matching completion, and then enters another electromagnetic environment; in addition, the above scheme also has a matching circuit complexity and implementation. It is difficult, costly, and less feasible. Summary of the invention

In view of this, the main object of the present invention is to provide an impedance matching apparatus and method capable of improving the degree of adaptive matching between a mobile terminal and a matching target in a relatively simple circuit form.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

The present invention provides an impedance matching apparatus, the apparatus comprising: a detection circuit, a decision circuit, and a matching control circuit;

a detection circuit for processing the reflected signal intensity S _N reflected from the matching target; wherein N is the number of times of sampling;

a decision circuit, configured to determine, according to the decision condition, a matching state of the matching network in the matching control circuit;

The matching control circuit is configured to adjust a control voltage of the matching impedance of the matching network in the matching control circuit according to the judgment result of the decision circuit.

In the above solution, the processing of the detecting circuit is specifically detected and detected, and includes: a circulator, a detector, a command reader, and a register; wherein

a circulator for isolating the power signal p _n of the radio frequency power amplifier or the reflected signal strength S _{N of the} matching target; a detector for detecting and detecting the reflected signal strength S _{N of the} circulator, and storing S _N in the register, wherein N is the number of times of sampling;

a command reader, configured to read a power control command from a chip of the mobile terminal, and save the power signal P _n corresponding to the power control command in a register;

A register for storing the intensity of the reflected signal S _N, S _N with the equivalent impedance corresponding to the control voltage V _N, n, and power level corresponding to the power signal P _n.

In the above solution, the circulator isolates the power signal or the reflected signal, specifically: the power signal P _{n of the} radio frequency power amplifier is sent to the matching target through the circulator or the matching network; or, the reflected signal strength S _{N of the} matching target , sent to the detector through the matching network and circulator.

In the above solution, the decision circuit includes: a signal processor; wherein

a signal processor, configured to read the reflected signal strengths S _N , S _N -! , S _N+1 and the power signal P _n from the register, and adjust the equivalent impedance by the matching control circuit according to the set decision condition Control voltage.

In the above solution, the signal processor causes the matching control circuit to adjust the control voltage of the equivalent impedance according to the decision condition, specifically:

Select one of the equivalent impedances in the matching network, adjust the control voltage of the equivalent impedance, and keep the control voltages of the other two equivalent impedances unchanged; the signal processor reads S _N , S _N -!, S from the register _N+1 and P _n , and according to the steepest descent algorithm, it is judged whether S _N satisfies the judgment condition one: (S _N ) ² /P _n <0.001, and when the judgment condition is satisfied, the control of the equivalent impedance at the time of the Nth sample is maintained. The voltage V _{N is} unchanged, and the S _N at this time is stored in the register; if the decision condition is not satisfied, according to the decision condition two: N<5000, S _N+ i > S _N and S _N < S _N -i , the slave register read satisfying the judgment condition II S _N, and Sr ^ corresponding to the equivalent impedance of the control voltage V _N, the equivalent impedance of the control voltage preclude comp time _{N + 1} V N + 1 is adjusted to preclude N th sample timing control voltage V _N, and S _N stored in the register.

In the above solution, the matching control circuit comprises: an adjustment circuit, a control voltage PWM generation Module and matching network;

The adjusting circuit is configured to select any one of the three equivalent impedances of the matching network to adjust the control voltage thereof;

a control voltage PWM generating module for adjusting a control voltage of an equivalent impedance required to be adjusted according to a command of the signal processor and the adjusting circuit, and storing the control voltage in a register; a matching network for implementing the RF power amplifier Match the impedance with the matching target. In the above solution, the equivalent impedance in the matching control circuit uses a varactor diode.

The invention also provides an impedance matching method, the method comprising:

According to the reflected signal strength S _N and the power P _{n of the} RF power amplifier, the control voltage of the equivalent impedance of the matching network is adjusted by corresponding decision conditions to achieve adaptive matching of the RF power amplifier and the matching target.

In the above solution, the equivalent impedance uses a varactor diode.

In the above solution, the control voltage for adjusting the equivalent impedance according to the S _N and P _n is determined by:

Select one of the equivalent impedances in the matching network, adjust the control voltage of the equivalent impedance, and keep the control voltages of the other two equivalent impedances unchanged; according to S _N , S _N -!, S _N+1 and P _n , And according to the steepest descent algorithm, it is calculated whether S _N satisfies the judgment condition one: (S _N ) ² /P _n <0.001, if the judgment condition one is satisfied, the control voltage of the equivalent impedance required to be adjusted at the Nth sample time is maintained. V _{N is} unchanged, and saves S _N at this time; if the judgment condition one is not satisfied, according to the judgment condition two: N<5000, S _N+ i > S _N and S _N < S _N _i, N+l the time required for adjusting the equivalent impedance control voltage V _{N + 1} is adjusted to preclude the kind of the N-th timing control voltage V _N, S and stores _N; wherein, N is the number of injections Bian.

In the above solution, after the control voltage of the equivalent impedance to be adjusted is adjusted, the method further comprises: maintaining the control voltage of the equivalent impedance unchanged, and sequentially adjusting the control voltages of the other two equivalent impedances.

In the above solution, the method further includes: adaptively adapting the RF power amplifier to the matching target After matching, if S _N+1 >1.25* S _N , then N needs to re-sample the reflected signal strength S _N from zero and jump out of the current matching state, and then adjust the equivalent by decision condition 1 or decision condition 2 The control voltage of the impedance re-matches the RF power amplifier with the matching target; if S _N+1 >1.25* S _N is not satisfied, the original matching state remains unchanged.

The impedance matching device and method provided by the present invention adjusts the control voltage of the equivalent impedance according to the reflected signal strength S _N and the power P _{n of the} radio frequency power amplifier to achieve the adaptive of the RF power amplifier and the matching target. match.

Compared with the prior art, the adaptive matching circuit relies on impedance calculation to realize circuit matching, simplifies the design of the conventional adaptive matching circuit, and saves the matching of the adaptive matching circuit. Time, shortening the cycle of design and debugging of mobile terminals, and enhancing the practicability of adaptive matching circuits.

In addition, the present invention determines whether the matching network is in a matching state or causes the matching network to enter a matching state by determining the judgment condition 1 or the judgment condition 2, so that the reflected signal strength can be reduced, and the RF power amplifier is protected from the reflected signal. The effect is to reduce the interference of the reflected signal to the outside and the mobile terminal board, thereby fundamentally improving the stability, linearity and the RF performance index of the RF power amplifier, thereby improving the call quality of the communication link. Moreover, the present invention can also reduce the transmission power of the radio frequency power amplifier under the same base station power requirement, thereby increasing the talk time of the mobile terminal and reducing the transmission power of the mobile terminal chip. DRAWINGS

1 is a structural diagram of a structure of an impedance matching apparatus according to an embodiment of the present invention;

2 is a schematic structural diagram of a prior art matching network;

3 is a block diagram showing an equivalent impedance structure in a matching network according to an embodiment of the present invention;

4 is a flow chart of an impedance matching method in an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION The basic idea of the invention is: based on the reflected signal strength S _N and the power of the radio frequency power amplifier

P _n , adjusting the control voltage of the equivalent impedance by corresponding decision conditions to achieve adaptive matching of the RF power amplifier and the matching target.

The impedance matching device provided by the present invention is located between the radio frequency power amplifier of the mobile terminal and the matching target, as shown in FIG. 1, and includes: a detecting circuit, a determining circuit, and a matching control circuit;

a detecting circuit for detecting and detecting a reflected signal intensity S _N reflected from the matching target; wherein N is a number of times;

a decision circuit, configured to determine, according to the reflected signal strength S _N and the power P _{n of the} radio frequency power amplifier, a matching condition of the matching network in the matching control circuit by the decision condition;

In Figure 1, the detection circuit includes: a circulator, a detector, a command reader, and a register;

a circulator for isolating the power signal P _n of the radio frequency power amplifier or the reflected signal strength S _{N of the} matching target; wherein, P _n is a power signal corresponding to the power level n; when the mobile terminal is in different states, the corresponding The power level n is different.

Specifically, when the power signal P _{n of the} RF power amplifier is sent to the matching target through the circulator and the matching network, the conduction direction of the circulator is the direction of the RF power amplifier to the matching network, that is, the power signal does not pass through the loop. The device sends to the detector; when the matching target signal S _N is sent to the detector through the matching network and the circulator, the conduction direction of the circulator is the matching network to the detector direction, that is, the reflected signal does not pass. The circulator is sent back to the power amplifier.

a detector for detecting and detecting a reflected signal intensity S _N through the circulator and storing the reflected signal strength S _N in a register, wherein N is a number of times; a command reader, configured to read a power control command from a chip of the mobile terminal, and save the power signal P _n corresponding to the power control command in a register;

Register, a control voltage for storing the reflected signal strength S _N , the equivalent impedance corresponding to S _N

V _N , and the power signal P _n corresponding to the power level _n ;

The decision circuit includes: a signal processor; wherein

a signal processor, configured to read S _N , S _N -! , S _N+1 and P _n from the register, and, according to the set decision condition, cause the matching control circuit to adjust the control voltage of the equivalent impedance to make a matching network Enter the matching state;

Specifically, the signal processor reads S _N , S _N -! , S _N+1 and P _n from the register, and according to the steepest descent algorithm, determines whether S _N satisfies the decision condition one: (S _N ) ² /P _n <0.001, if the judgment condition one is satisfied, indicating that the matching network is in the matching state, the control voltage V _{N of the} equivalent impedance at the Nth sampling time is immediately maintained, and the reflected signal strength S _N at this time is stored in the register. If the judgment condition one is not satisfied, according to the judgment condition two: N<5000, 8^ ₁ > 8^^ and 8^^ < 8^ ₁ , the reflected signal strength S _N satisfying the decision condition 2 is read from the register. and S _N with the equivalent impedance corresponding to the control voltage V _N, and the control voltage + 1 time samples preclude equivalent impedance regulation V _{N + 1} and N is the N-th preclude timing control voltage V comp _N , the matching network enters a matching state, and stores S _N in a register; wherein, the decision condition 1 and the decision condition 2 are preset in the signal processor;

The matching control circuit includes: an adjustment circuit, a control voltage PWM generating module, and a matching network; wherein

An adjustment circuit for selecting an equivalent impedance from three equivalent impedances of the matching network to adjust its control voltage;

a control voltage PWM generating module for adjusting a control voltage of an equivalent impedance required to be adjusted according to a command of the signal processor and the adjusting circuit, and storing the control voltage in a register; a matching network for implementing the RF power amplifier Match the impedance with the matching target to Reduce the intensity of the reflected signal. The matching network is implemented by a T network or a network. As shown in Figure 2, Zl, Z2, and Z3 are three equivalent impedances in the matching network, which can be realized by equivalent capacitance or equivalent inductance; Capacitors or equivalent inductors can be replaced with varactors.

In the matching network of the present invention, the series or parallel connection of the varactor diode and the capacitor can also be used to expand the dynamic adjustment range of the equivalent capacitor, and the dynamic adjustment range of the equivalent inductor can be expanded in the same manner. Here, taking the equivalent capacitance as an example, as shown in FIG. 3(a), by closing the switch 1 and the switch 2 in FIG. 3(a), the parallel connection mode of the varactor diode and the capacitor 1 can be realized. The equivalent capacitance is extended to the maximum value, as shown in Figure 3 (b). By disconnecting the switch 1 and the switch 2 in Figure 3 (a), the series connection of the varactor diode and the capacitor 2 can be realized. The equivalent capacitance is extended to the minimum value as shown in Figure 3 (c).

Among them, the size of the shunt capacitor 1 determines the minimum value of its equivalent capacitance; the size of the series capacitor 2 determines the maximum value of its equivalent capacitance.

Assuming that the adjustable range of the varactor is [Α, Β], the value of the series capacitor 2 in Figure 3 is C, and the value of the shunt capacitor 1 is D. To ensure the continuous adjustability of the capacitor within the maximum dynamic range, it must be satisfied. :

Γ ― ¹ ― A

^SMax― 丄 +丄 ― ^

C _PMin =A + D = B

Wherein, C _SMAX represents the maximum value of the equivalent capacitance when the varactor diode is connected in parallel with the capacitor; C _PMin represents the minimum value of the equivalent capacitance when the varactor diode is connected in series with the capacitor;

Thereby it is possible to determine:

r ^ = -丄_ ^L丄-

D = B-A

The dynamic range of the equivalent capacitance in the matching network can be obtained as follows: - ' , Β -A] From this, it can be seen that after using the varactor diode, the dynamic range of the equivalent capacitance in the matching network is expanded.

In the above device, if the matching network is in the matching state, the detecting circuit and the determining circuit work, the matching control circuit keeps the control voltage of the equivalent impedance constant, and enters the power saving mode; if the matching network is not in the matching state, the detecting circuit and the determining circuit And the matching control circuit works until the matching condition is met, and the matching network enters the matching state. In addition, when the mobile terminal is not in a call state, the detector, the decision circuit, and the matching control circuit are in an inoperative state, and only the circulator is in operation.

Based on the above device, the present invention also provides an impedance matching method. As shown in FIG. 4, the method includes:

Step 401: Read a power control command;

In this step, the detecting circuit reads the power control command from the chip of the mobile terminal, and obtains the corresponding power according to the power control command. And storing the power control command for controlling the power P _n corresponding to the power level n of the radio frequency power amplifier. When the mobile terminal, such as a mobile phone, is in different states, the power level n is also different.

Step 402: transmitting a power signal to a matching target;

In this step, the RF power amplifier sends the power signal P _n to the matching target through the circulator and the matching network, such as the mobile phone antenna; because the circulator has high isolation, the conduction direction of the circulator is the RF power amplifier. To match the network direction, that is, the power signal is not sent to the detector through the circulator.

Step 403: detecting a reflected signal strength;

In this step: the matching target sends the reflected signal to the detector through the matching network and the circulator; because the circulator has a high isolation, the conduction direction of the circulator is the matching network to the detector direction, that is, The reflected signal is not sent back to the RF power amplifier through the circulator; the detector passes a certain sampling period, detects the reflected signal strength S _N after passing through the circulator, and stores it Stored in a register;

Where N is the total number of times, for each sample, the value of N is increased by 1; depending on the decision circuit algorithm, registers of different capacities can be selected.

Step 404: Select one of the equivalent impedances in the matching network, adjust the control voltage of the equivalent impedance, and keep the control voltages of the other two equivalent impedances unchanged;

Step 405: Determine whether the judgment condition one is satisfied: (S _N ) ² /P _n <0.001. If the condition one is satisfied, the control voltage of the equivalent impedance is kept unchanged when the Nth sample is kept, and S _{N is} stored and executed. Step 407; If the condition one is not met, step 406 is performed;

In this step, the signal processor reads S _N , S _N -! , S _N+1 and P _n from the register, and according to the steepest descent algorithm, determines whether S _N and P _{n of the} same sample time satisfy the judgment condition one. : (S _N ) ² /P _n <0.001. If condition 1 is satisfied, the reflected signal strength S _N at this time is the minimum, and the equivalent impedance of the required adjustment in the matching network is in the matching state, and the Nth time is immediately maintained. The control voltage V _N of the equivalent impedance is unchanged at the sample time, and the reflected signal strength S _N at this time is stored in the register.

Step 406: Determine whether the condition 2 is satisfied: N<5000, 8^ ₁ > 8^^ and 8^^ < 8^ ₁ . If the condition 2 is satisfied, the control voltage for adjusting the equivalent impedance is V _N , and storing S _N , step 407 is performed; if condition 2 is not met, the RF power amplifier cannot match the matching target, terminate the loop, and end the current processing flow.

In this step, if the judgment condition one is not satisfied, according to the judgment condition two: N<5000, S _N+ i > S _N and S _N < S _N _ _l find the S _N satisfying the condition two from the register, and the S _N equivalent impedance corresponding to a desired control voltage adjustment V _N, N + and the equivalent control voltage V _{N + 1} impedance adjusting a control voltage V _N at the N-th Bian Bian-like sample 1 while the The equivalent impedance of the desired adjustment in the matching network enters the matching state, and stores S _N in the register, at which time the reflected signal strength S _N is the smallest. If condition 2 is not met, the matching network cannot enter the matching state, that is, the RF power amplifier cannot match the matching target, and the loop is terminated.

Step 407: Keep the control voltage of the equivalent impedance unchanged, and sequentially adjust the other two equivalent resistances. Resistance control voltage;

In this step, the voltage V _{N of} the equivalent impedance is kept unchanged, and according to the steepest descent algorithm and the above two decision conditions, the control voltages of the other two equivalent impedances in the matching network are sequentially adjusted according to the determination process of steps 405 to 406 above. Until the three equivalent impedances in the matching network fully enter the matching state.

Step 408: Determine whether it is satisfied: S _N+1 >1.25* S _N ; if the condition is met, return to step 405; otherwise, maintain the original matching state;

In this step, when the matching network is in the matching state, the matching state may be damaged due to the change of the real-time environment. If S _N+1 >1.25* S _N , indicating that the matching state is damaged, delete the previous one. The stored reflected signal strength S _N , and jumps out of the current matching state, restarts the sampling, that is, N detects S _N from 0, and then re-adjusts the control voltage of the equivalent impedance in the matching network, so that the matching network re-enters the matching state; If S _N+ i >1.25* S _{N is} not satisfied, the matching state is not destroyed, and the original matching state is kept unchanged, that is, the control voltage of the equivalent impedance in the matching network is not changed.

According to the method of the present invention, the control voltage of the equivalent impedance in the matching network can be adaptively adjusted according to the needs of the environment to obtain the minimum reflected signal S _N , so that the matching network realizes the relationship between the RF power amplifier and the matching target. Good match.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included. Within the scope of protection of the present invention.

Claims

Claim

An impedance matching device, comprising: a detection circuit, a decision circuit, and a matching control circuit; wherein

a decision circuit, configured to determine, according to the set decision condition, a matching state of the matching network in the matching control circuit;

2. The device according to claim 1, wherein the processing of the detecting circuit is specifically detected and detected, and includes: a circulator, a detector, a command reader, and a register; wherein, the circulator is used Isolating the power signal P _n of the radio frequency power amplifier or the reflected signal strength S _{N of the} matching target;

a detector for detecting and detecting the reflected signal strength S _{N of the} circulator, and storing S _N in the register, wherein N is the number of times of sampling;

a command reader, configured to read a power control command from a chip of the mobile terminal, and save the power signal P _n corresponding to the read power control command in a register;

The device according to claim 2, wherein the circulator isolates the power signal or the reflected signal, specifically: the power signal P _{n of the} radio frequency power amplifier is sent to the matching target through the circulator and the matching network. Or, the reflected signal strength S _{N of the} matching target is sent to the detector through the matching network and the circulator.

4. The apparatus according to claim 2, wherein the decision circuit comprises: a signal processor; a signal processor, configured to read the reflected signal strengths S _N , S _N -! , S _N+1 and the power signal P _N from the register, and adjust the equivalent impedance by the matching control circuit according to the set decision condition Control voltage.

5. The apparatus according to claim 4, wherein the signal processor causes the matching control circuit to adjust the control voltage of the equivalent impedance according to the determination condition, specifically:

Selecting an equivalent impedance in the matching network, adjusting the control voltage of the selected equivalent impedance, and maintaining the control voltage of other equivalent impedances unchanged;

The signal processor reads S _N , S _N -! , S _N+1 and P _N from the register, and according to the steepest descent algorithm, determines whether S _N satisfies the decision condition one: (S _N ) ² /P _N <0.001, When the judgment condition is satisfied, the control voltage V _{N of the} equivalent impedance at the time of the Nth sample is kept unchanged, and the S _N at this time is stored in the register; if the judgment condition is not satisfied, according to the judgment condition 2: N<5000, S _{_N + 1>} S _N and S _{_N} <S _N -i, read from the register judgment satisfies the condition S _n II, and S _N, and a control voltage corresponding to the equivalent impedance of V _N, N + 1 would preclude comp equivalent impedance control voltage V _{N + 1} time is adjusted to preclude the kind of the N-th timing control voltage V _N, and S _N stored in the register.

The device according to claim 1, wherein the matching control circuit comprises: an adjustment circuit, a control voltage PWM generating module, and a matching network;

a control voltage PWM generating module for adjusting a control voltage of an equivalent impedance required to be adjusted according to a command of the signal processor and the adjusting circuit, and storing the control voltage in a register; a matching network for implementing the RF power amplifier Match the impedance with the matching target.

7. Apparatus according to any one of claims 1 to 6, wherein the equivalent impedance in the matching control circuit uses a varactor.

8. An impedance matching method, the method comprising:

According to the reflected signal strength S _N and the power P _{N of the} radio frequency power amplifier, the corresponding decision strip is passed. A control voltage that adjusts the equivalent impedance of the matching network to achieve adaptive matching of the RF power amplifier to the matching target.

9. The method of claim 8 wherein the equivalent impedance uses a varactor diode.

The method according to claim 8 or 9, wherein the control voltage for adjusting the equivalent impedance according to the S _N and P _n is determined by:

According to S _N , S _N -!, S _N+1 and P _n , and according to the steepest descent algorithm, it is calculated whether S _N satisfies the judgment condition one: (S _N ) ² /P _n <0.001, if the judgment condition one is satisfied, The control voltage v _N of the equivalent impedance required to maintain the Nth sample time is unchanged, and saves S _N at this time; if the judgment condition 1 is not satisfied, according to the decision condition 2: N<5000, S _N+ i > S _N and S _{_N} <S _N -i, N + l will preclude the control voltage required for adjusting the timing comp equivalent impedance of V _{N + 1} is adjusted to preclude the kind of the N-th timing control voltage V _N, S and save _N ; where N is the number of times.

11. The method according to claim 10, wherein after the control voltage adjustment of the equivalent impedance required to be adjusted, the method further comprises: maintaining the control voltage of the selected equivalent impedance unchanged, sequentially adjusting other conditions, etc. The control voltage of the effective impedance.

12. The method according to claim 11, wherein the method further comprises: after the RF power amplifier is adaptively matched with the matching target, if S _N+1 >1.25* S _N , the N needs to be started from zero. Re-sampling the reflected signal strength S _N and jumping out of the current matching state, and re-adjusting the control voltage of the equivalent impedance by the decision condition 1 or the decision condition 2, so that the RF power amplifier and the matching target are re-matched; if the S _{N+ is} not satisfied ₁ >1.25* S _N , the original matching state remains unchanged.