CN105391416A - Load impedance matching device and matching method - Google Patents

Abstract

The invention discloses a load impedance matching device and a matching method, belonging to the field of impedance matching. The invention includes a surface acoustic wave device adapter seat, one end of which is connected with a matching circuit unit of port one, and the other end is connected with a matching circuit unit of port two, the matching circuit unit of port one is connected with the first connector, and the matching circuit unit of port two is connected The circuit unit is connected with the second connector. In the present invention, by adjusting the states of the four single-pole double-throw switches in the device, an unmatched channel and a matching channel corresponding to the surface acoustic wave device to be tested are respectively formed, so that the surface acoustic wave device to be tested can complete the load impedance matching in one step. Compared with the existing technology, it avoids the disassembly of multiple hardware in the whole process, and can design different passive load impedance matching networks for the two ports, and flexibly handle the two ports to achieve impedance matching at the same time The center point reduces the reflected wave on the transmission line and improves the transmission efficiency and quality of the surface acoustic wave signal.

Description

A load impedance matching device and matching method

technical field

The invention belongs to the field of impedance matching, in particular to a load impedance matching device and a matching method.

Background technique

Load impedance matching means that the load impedance is equal to the characteristic impedance of the transmission line, which is a state in which high-frequency microwave signals can be transmitted to the load point with maximum power. The output of the surface acoustic device is a high-frequency analog signal, which will lead to strong reflected waves on the transmission line in the case of load impedance mismatch, which directly affects the transmission efficiency and quality of the signal.

At present, there are many methods for load impedance matching of surface acoustic wave devices, but none of them can solve the load matching problem well:

First of all, most of the currently existing load matching schemes for surface acoustic wave devices cannot make the input and output ports match at the same time, and there are still large reflected waves at the connection transmission line between the two ports;

Secondly, the existing surface acoustic wave device load matching lacks a systematic matching device and matching scheme. The traditional method repeatedly disassembles the hardware and compares the measurement, which makes the matching take a lot of time and energy.

Contents of the invention

In order to solve the problems of the prior art, in a first aspect, the present invention provides a load impedance matching device, and the load impedance matching device includes:

A surface acoustic wave device adapter seat, one end of the surface acoustic wave device adapter seat is connected to a port one matching circuit unit, and the other end of the surface acoustic wave device adapter seat is connected to a port two matching circuit unit, the port A matching circuit unit is connected to the first connector, and a second matching circuit unit is connected to the second connector at the port;

Wherein, the surface acoustic wave device adapter seat is connected to the matching circuit unit of port 1 through a first single-pole double-throw switch, and the surface acoustic wave device adapter seat is matched with the port 2 through a second single-pole double-throw switch circuit unit connection;

A third single-pole double-throw switch is arranged between the port-one matching circuit unit and the first connector, and a fourth single-pole double-throw switch is arranged between the port-two matching circuit unit and the second connector.

Optionally, the surface acoustic wave device adapter includes:

One end of the surface acoustic wave device adapter seat is provided with an In port connected to the input pin of the acoustic wave device to be tested, and an In port connected to the output pin of the acoustic wave device to be tested is provided at the other end of the surface acoustic wave device adapter seat. Connected Out port.

Optionally, the port-matching circuit unit includes:

Capacitor C11, inductor L11, inductor L12;

Wherein, one end of the inductor L11 is connected to one end of the capacitor C11, the other end of the inductor L11 is grounded, one end of the inductor L12 is connected to the other end of the capacitor C11, and the other end of the inductor L12 is grounded , one end of the capacitor C11 is connected to the first single-pole double-throw switch, and the other end of the capacitor C11 is connected to the third single-pole double-throw switch.

Optionally, the port two matching circuit unit includes:

Capacitor C21, inductor L21, inductor L22;

Wherein, one end of the inductor L21 and one end of the inductor L22 are commonly connected to one end of the capacitor C21, the other end of the inductor L21 is connected to the second SPDT switch, and the other end of the inductor L22 grounded, and the other end of the capacitor C21 is connected to the fourth SPDT switch.

In the second aspect, the present invention also provides a load impedance matching method, and the load impedance matching method includes:

Step 1, connecting the load impedance matching device as described in the first aspect to the port of the network analyzer through a transmission line;

Step 2, place the surface acoustic wave device to be tested in the surface acoustic wave device adapter seat in the load impedance matching device, adjust the first single-pole double-throw switch, the second single-pole double-throw switch, and the third single-pole double-throw switch , the state of the fourth single-pole double-throw switch, so that the surface acoustic wave device to be tested is connected to an unmatched channel;

Step 3, measuring the impedance of the surface acoustic wave device itself;

Step 4, combined with the matching network structure diagram, build a passive impedance matching network;

Step five, determine the passive impedance matching network value;

Step 6, determining the values of all passive load matching networks located at port 1 and port 2 in the load impedance matching device, and building a load matching circuit associated with port 1 and port 2;

Step 7, adjusting the states of the first SPDT switch, the second SPDT switch, the third SPDT switch, and the fourth SPDT switch, and connecting the SAW device to be tested into a matching channel, Complete load matching.

Optionally, the determination of the passive impedance matching network value includes:

According to formula 1 and formula 2, combined with the Smith matching locus diagram to determine the value of the passive impedance matching network;

$L_{match}=\frac{1}{h\×Y_0\×\mathrm{\ω}}=\frac{1}{h\×Y_0\×2\mathrm{\π}f},$ formula one

$C_{match}=\frac{1}{h\×Z_0\×\mathrm{\ω}}=\frac{1}{h\×Z_0\×2\mathrm{\π}f},$ formula two

Among them, h is the arc length of the track to be matched, Z0 is the characteristic impedance of the transmission line of the vector network analyzer, f is the center frequency of the surface acoustic wave device, L _match is the matching inductance value, and C _match is the matching capacitance value.

The beneficial effects brought by the technical scheme provided by the invention are:

Through the adjustment of the states of the four single-pole double-throw switches in the device, an unmatched channel and a matching channel corresponding to the surface acoustic wave device to be tested are respectively formed, so that the surface acoustic wave device to be tested can complete the load impedance matching in one step. Compared with the existing technology, it avoids the disassembly of multiple hardware in the whole process, and can design different passive load impedance matching networks for the two ports, and flexibly handle the two ports to achieve impedance matching at the same time The center point reduces the reflected wave on the transmission line and improves the transmission efficiency and quality of the surface acoustic wave signal.

Description of drawings

In order to illustrate the technical solution of the present invention more clearly, the accompanying drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. Ordinary technicians can also obtain other drawings based on these drawings on the premise of not paying creative work.

Fig. 1 is a schematic diagram of the overall structure of a load impedance matching device provided by the present invention;

Fig. 2 is a schematic circuit structure diagram of a load impedance matching device provided by the present invention;

3 is a schematic structural diagram of a port-matching circuit in a load impedance matching device provided by the present invention;

4 is a schematic structural diagram of a port two matching circuit in a load impedance matching device provided by the present invention;

Fig. 5 is a schematic flow chart of a load impedance matching method provided by the present invention;

Fig. 6 is a Smith matching locus diagram of a load impedance matching method provided by the present invention;

Fig. 7 is a matching network structure diagram of a load impedance matching method provided by the present invention;

Fig. 8 is a matched S11 impedance diagram of a load impedance matching method provided by the present invention;

FIG. 9 is a matched S22 impedance chart of a load impedance matching method provided by the present invention.

detailed description

In order to make the structure and advantages of the present invention clearer, the structure of the present invention will be further described below in conjunction with the accompanying drawings.

Embodiment one

The present invention provides a load impedance matching device. The load impedance matching device includes:

A surface acoustic wave device adapter seat, one end of the surface acoustic wave device adapter seat is connected to a port one matching circuit unit, and the other end of the surface acoustic wave device adapter seat is connected to a port two matching circuit unit, the port A matching circuit unit is connected to the first connector, and a second matching circuit unit is connected to the second connector at the port;

Wherein, the surface acoustic wave device adapter seat is connected to the matching circuit unit of port 1 through a first single-pole double-throw switch, and the surface acoustic wave device adapter seat is matched with the port 2 through a second single-pole double-throw switch circuit unit connection;

A third single-pole double-throw switch is arranged between the port-one matching circuit unit and the first connector, and a fourth single-pole double-throw switch is arranged between the port-two matching circuit unit and the second connector.

In practice, in order to solve the defect that the input port and the output port of the surface acoustic wave device in the prior art cannot reach the matching state at the same time, the present invention proposes a load impedance matching device, as shown in Figure 1, the device The detailed structure is as follows:

The main body of the load impedance matching device is the surface acoustic wave device adapter seat, and the two ends of the adapter seat are respectively connected with the port one matching circuit unit and the port two matching circuit unit, and the port one matching circuit unit and the port two matching circuit unit They are connected to the first joint and the second joint respectively.

Among them, a first single-pole double-throw switch S1 is arranged between the matching circuit unit of port one and the adapter seat of the surface acoustic wave device, and a second single-pole double-throw switch S1 is arranged between the matching circuit unit of port two and the adapter seat of the surface acoustic wave device Switch S2. A third SPDT switch S3 is arranged between the matching circuit unit of port one and the first connector, and a fourth SPDT switch S4 is arranged between the matching circuit unit of port two and the second connector.

Specifically, in FIG. 2, when the SPDT switch S1 is located at the S11 terminal, the SPDT switch S2 is located at the S21 terminal, the SPDT switch S3 is located at the S31 terminal, and the SPDT switch S4 is located at the S41 terminal, the first connector, the acoustic The channel connecting the surface wave device and the second joint constitutes an unmatched channel;

When the SPDT switch S1 is located at the S12 terminal, the SPDT switch S2 is located at the S22 terminal, the SPDT switch S3 is located at the S32 terminal, and the SPDT switch S4 is located at the S42 terminal, the first connector, the port-matching circuit unit, the surface acoustic wave The device, the port 2 matching circuit unit and the second joint connection channel form a matching channel.

Since four single-pole double-throw switches are designed in the entire load impedance matching device, by adjusting the specific connection status of the four single-pole double-throw switches, it can be installed on the surface acoustic wave device adapter seat when performing load impedance matching. The SAW device to be tested is respectively connected to the unmatched channel and the matched channel, and different passive impedance matching networks can be built for port 1 and port 2, so that port 1 and port 2 reach the load impedance matching point at the same time, reducing two The reflected wave of the source-to-load transmission signal on the end transmission line.

The invention provides a load impedance matching device, including a surface acoustic wave device adapter seat, and a port-one matching circuit unit and a port-two matching circuit unit connected thereto, through the adjustment of the state of four single-pole double-throw switches in the device , respectively constitute an unmatched channel and a matching channel corresponding to the surface acoustic wave device to be tested, so that the surface acoustic wave device to be tested can complete the load impedance matching in one step. Compared with the existing technology, it avoids the disassembly of multiple hardware in the whole process, and can design different passive load impedance matching networks for the two ports, and flexibly handle the two ports to achieve impedance matching at the same time The center point reduces the reflected wave on the transmission line and improves the transmission efficiency and quality of the surface acoustic wave signal.

Optionally, the surface acoustic wave device adapter includes:

One end of the surface acoustic wave device adapter seat is provided with an In port connected to the input pin of the acoustic wave device to be tested, and an In port connected to the output pin of the acoustic wave device to be tested is provided at the other end of the surface acoustic wave device adapter seat. Connected Out port.

In implementation, the In port of the surface acoustic wave device adapter seat is connected to the input pin of the surface acoustic wave device to be tested, and the Out port of the surface acoustic wave device adapter seat is connected to the output pin of the surface acoustic wave device to be tested.

Through the above connections, the surface acoustic wave device to be tested is connected to the entire load impedance matching device through the adapter seat of the surface acoustic wave device.

Optionally, the port-matching circuit unit includes:

Capacitor C11, inductor L11, inductor L12;

Wherein, one end of the inductor L11 is connected to one end of the capacitor C11, the other end of the inductor L11 is grounded, one end of the inductor L12 is connected to the other end of the capacitor C11, and the other end of the inductor L12 is grounded , one end of the capacitor C11 is connected to the first single-pole double-throw switch, and the other end of the capacitor C11 is connected to the third single-pole double-throw switch.

In practice, the details of the port-one matching circuit unit are shown in Figure 3, one end of the capacitor C11 is connected to the S32 end of the third SPDT switch S3, and the other end of the capacitor C11 is connected to the first SPDT switch S1 S12 terminal, and one end of the inductor L11 is connected to one end of the capacitor C11, the other end of the inductor L11 is grounded, similarly, one end of the inductor L11 is connected to the other end of the capacitor C11, and the other end of the inductor L12 is grounded.

The above-mentioned structure of the port-matching circuit unit is also called a π-type circuit.

Optionally, the port two matching circuit unit includes:

Capacitor C21, inductor L21, inductor L22;

Wherein, one end of the inductor L21 and one end of the inductor L22 are commonly connected to one end of the capacitor C21, the other end of the inductor L21 is connected to the second SPDT switch, and the other end of the inductor L22 grounded, and the other end of the capacitor C21 is connected to the fourth SPDT switch.

In practice, the details of the port 2 matching circuit unit are shown in FIG. 4 , one end of the inductor L21 and one end of the inductor L22 are connected to one end of the capacitor C21, and the other end of the inductor L21 is connected to the second SPDT switch S2 The other end of the inductor L21 is grounded, and the other end of the capacitor C21 is connected to the S42 end of the fourth SPDT switch S4.

The above structure of the port 2 matching circuit unit is also called a T-shaped circuit.

The invention provides a load impedance matching device, including a surface acoustic wave device adapter seat, and a port-one matching circuit unit and a port-two matching circuit unit connected thereto, through the adjustment of the state of four single-pole double-throw switches in the device , respectively constitute an unmatched channel and a matching channel corresponding to the surface acoustic wave device to be tested, so that the surface acoustic wave device to be tested can complete the load impedance matching in one step. Compared with the existing technology, it avoids the disassembly of multiple hardware in the whole process, and can design different passive load impedance matching networks for the two ports, and flexibly handle the two ports to achieve impedance matching at the same time The center point reduces the reflected wave on the transmission line and improves the transmission efficiency and quality of the surface acoustic wave signal.

Embodiment two

The present invention provides a load impedance matching method, as shown in Figure 5, the load impedance matching method is specifically as follows:

Step 1, connecting the load impedance matching device to the port of the network analyzer through the transmission line;

Step 2, place the surface acoustic wave device to be tested in the surface acoustic wave device adapter seat in the load impedance matching device, adjust the first single-pole double-throw switch, the second single-pole double-throw switch, and the third single-pole double-throw switch , the state of the fourth single-pole double-throw switch, so that the surface acoustic wave device to be tested is connected to an unmatched channel;

Step 3, measuring the impedance of the surface acoustic wave device itself;

Step 4, combined with the matching network structure diagram, build a passive impedance matching network;

Step five, determine the passive impedance matching network value;

Step 6, determining the values of all passive load matching networks located at port 1 and port 2 in the load impedance matching device, and building a load matching circuit associated with port 1 and port 2;

Step 7, adjusting the states of the first SPDT switch, the second SPDT switch, the third SPDT switch, and the fourth SPDT switch, and connecting the SAW device to be tested into a matching channel, Complete load matching.

In implementation, based on the load impedance matching device described in the first embodiment, this embodiment proposes a load impedance matching method. For ease of description, this embodiment adopts a surface acoustic wave device with a center frequency of 101.764 MHz and a bandwidth of 30 MHz, and the surface acoustic wave adapter seat is a 24-pin base.

First, connect the first connector in the load impedance matching device to the Port1 port of the network analyzer through the transmission line, and connect the second connector in the load impedance matching device to the Port2 port of the network analyzer through the transmission line.

Next, place the SAW device to be tested in the SAW device adapter seat in the load impedance matching device, place the SPDT switch S1 at the S11 terminal, the SPDT switch S2 at the S21 terminal, and the SPDT switch S3 When the S31 is located and the SPDT switch S4 is located at the S41 end, the SAW device to be tested is connected to the unmatched channel integrally formed by the first connector, the SAW device and the second connector connection channel.

Then, to measure the S11 and S22 impedances of the surface acoustic wave device itself, in fact, the input reflection coefficient S11 and the output reflection coefficient of the surface acoustic wave device to be tested are respectively measured on the network analyzer using the Smith chart shown in Figure 6 The impedance of S22 at the center frequency point. It should be noted that S11 and S22 here are the input and output reflection coefficients of the surface acoustic wave to be measured, which are specific measurement parameters for the network analyzer, and have different meanings from the parameters representing switches in the attached figure.

Exemplarily, the two obtained impedance values are S11=11.43Ω−j10.87Ω, and S22=54.19Ω+j38.49Ω.

Thirdly, according to the matching network structure diagram shown in Fig. 7, a passive impedance matching network is built for port 1 and port 2 after proper adjustment according to the impedance position. According to the different positions of S11 and S22 at the center frequency point in the Smith chart in the previous step, combined with the matching network structure diagram shown in Figure 7, different passive impedance matching networks are built for port 1 and port 2 respectively.

In the matching network structure diagram shown in Figure 7, six positions from 1 to 6 correspond to different matching circuit structures. Through these six different matching circuit structures, the impedance position can reach the center point of the impedance matching circle. For the specific position in FIG. 7 , select the circuit structure corresponding to the position.

Exemplarily, the port 1 matching circuit unit adopts the π-type circuit at position 3 in FIG. 7 , the port 2 matching circuit unit adopts the T-type circuit, and after adjustment, adopts the T-type circuit at position 5 in FIG. 7 .

Next, according to the above selected different types of circuits, determine the value of the passive impedance matching network. There are equal resistance circles, equal conductance circles, etc. in the matching locus diagram, all of which belong to the Smith chart. The location of the impedance at the center frequency point in the graph changes.

Specifically, when the inductance is connected in series to the surface acoustic wave device, the inductance is increased. At this time, the impedance position moves clockwise along the equal-resistance circle, and the parallel inductance reduces the inductance and moves counterclockwise along the equal-conductance circle. According to the above changing law, through continuous adjustment, the impedance position can be moved step by step to reach the center point of the impedance matching circle. The specific movement amount and the corresponding resistance and capacitance values are calculated by the formula. The network value in this step is the inductance and capacitance value in the T-type or π-type circuit mentioned in the previous step.

At this point, the type of matching circuit used has been determined according to the preceding steps. In the Smith chart, the inductance value and capacitance value to be adjusted can be determined according to the arc length to be moved, that is, the port in the load impedance matching device is determined. All passive loads on ports one and two match the network values. Further, aiming at the "SAW device with a center frequency of 101.764MHz and a bandwidth of 30MHz, the SAW adapter seat is a 24-pin base" proposed in the previous article, a π-type circuit was built at port 1, and a π-type circuit was built at port 2. The T-shaped circuit makes it reach the center point of the impedance matching circle. In order to match different surface acoustic wave devices, different networks will be built.

Finally, when matching a surface acoustic wave device, different surface acoustic wave devices themselves have different impedances, so it is first necessary to connect it to the unmatched channel, and then measure the aforementioned impedance S11 and its own impedance. Impedance S22, then complete the matching network according to steps 3 to 6, after determining all the network values in the matching network, and then adjust the switch to connect the surface acoustic wave device to the matching channel, so as to verify the matching result. Therefore, only one matching device is needed to complete the load impedance matching process for different surface acoustic wave devices.

Among them, all passive load matching network values of port 1 and port 2 are determined, and load matching circuits of port 1 and port 2 are built. At this time, the specific parameters of each component in the calculation circuit are as follows:

$L_{11}=\frac{1}{h\×Y_0\×2\mathrm{\π}f}=\frac{1}{0.0029\×0.02\×2\mathrm{\π}\×101.764\×{10}^6}\≈266.1\mathrm{\μ}h,$ Take 270μH here. $C_{11}=\frac{1}{h\×Z_0\×2\mathrm{\π}f}=\frac{1}{13.54\×50\×2\mathrm{\π}\×101.764\×{10}^6}\≈22.8pf,$ Take 22pF.

$L_{12}=\frac{1}{h\×Y_0\×2\mathrm{\π}f}=\frac{1}{0.0000144\×0.02\×2\mathrm{\π}\×101.764\×{10}^6}\≈53.6mh,$ Take 50mH.

$L_{\mathrm{twenty\; one}}=\frac{1}{h\×Y_0\×2\mathrm{\π}f}=\frac{1}{0.000178\×0.02\×2\mathrm{\π}\×101.764\×{10}^6}\≈43.4\mathrm{no}h,$ Take 40nH.

$L_{\mathrm{twenty\; two}}=\frac{1}{h\×Y_0\×2\mathrm{\π}f}=\frac{1}{0.0032\×0.02\×2\mathrm{\π}\×101.764\×{10}^6}\≈241.2\mathrm{\μ}h,$ Take 270μH.

$C_{\mathrm{twenty\; one}}=\frac{1}{h\×Z_0\×2\mathrm{\π}f}=\frac{1}{6.27\×50\×2\mathrm{\π}\×101.764\×{10}^6}\≈49.2pf,$ Take 47pF.

Adjust the SPDT switch S1 at S12, SPDT switch S2 at S22, SPDT switch S3 at S32, SPDT switch S4 at S42, connect the SAW device to be tested to the matching channel, complete load matching, and measure The impedance charts of S11 and S22 after matching are shown in Figure 8 and Figure 9 .

Figure 8 is the Smith impedance matching diagram of the input reflection coefficient S11 after the matching is completed. The measurement parameters are directly below the diagram. The measurement center frequency (Center) is 101.764MHz, the intermediate frequency bandwidth (IFBW) is set to 30KHz, and the scanning power range (Span) is 40MHz. The position marked 1 in Figure 8 is the center frequency point of the surface acoustic wave device to be tested. As shown in the upper left display, the frequency at the marked 1 point is 101.764MHz, the real part of the impedance is 50.763Ω, and the imaginary part is -3.4120Ω, that is After matching, the impedance of S11 at the center frequency point is: S11 = 50.763Ω-j3.4120Ω, after passing through the port-one matching circuit unit, S11 shows partial capacitive, the size is 458.36pF.

Figure 9 is the Smith impedance matching diagram of the input reflection coefficient S22 after the matching is completed. The measurement parameters are directly below the figure. The measurement center frequency (Center) is 101.764MHz, the intermediate frequency bandwidth (IFBW) is set to 30KHz, and the scanning power range (Span) is 40MHz. The position marked 1 in Figure 9 is the center frequency point of the surface acoustic wave device to be tested. As shown in the upper left display, the frequency at the marked 1 point is 101.764MHz, the real part of the impedance is 49.937Ω, and the imaginary part is -2.9931Ω, namely After matching, the impedance of S22 at the center frequency point is: S22 = 49.937Ω-2.9931Ω. After passing through the port 2 matching circuit unit, S22 is partially capacitive, with a size of 522.51pF.

Optionally, the determination of the passive impedance matching network value includes:

According to formula 1 and formula 2, combined with the Smith matching locus diagram to determine the value of the passive impedance matching network;

$L_{match}=\frac{1}{h\×Y_0\×\mathrm{\ω}}=\frac{1}{h\×Y_0\×2\mathrm{\π}f},$ formula one

$C_{match}=\frac{1}{h\×Z_0\×\mathrm{\ω}}=\frac{1}{h\×Z_0\×2\mathrm{\π}f},$ formula two

Among them, h is the arc length of the track to be matched, Z0 is the characteristic impedance of the transmission line of the vector network analyzer, f is the center frequency of the surface acoustic wave device, Lmatch is the matching inductance value, and Cmatch is the matching capacitance value.

In the implementation, the value of the passive impedance matching network is determined in combination with the Smith matching locus diagram, and the specific calculation formula is as follows:

${\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; \&omega;</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}\mathrm{<span\; class="notranslate">\; f</span>}}$

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; \&omega;</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}\mathrm{<span\; class="notranslate">\; f</span>}}$

Among them: h is the arc length of the track to be matched, Z0 is the characteristic impedance of the transmission line of the vector network analyzer, f is the center frequency of the surface acoustic wave device, Lmatch is the matching inductance value, and Cmatch is the matching capacitance value.

The invention provides a load impedance matching method, comprising using a connection line to connect a load impedance matching device to a network analyzer through a transmission line, and then placing a surface acoustic wave device to be tested in the load impedance matching device. In the adapter seat, adjust the state of the four single-pole double-throw switches, connect the surface acoustic wave device to be tested to the unmatched channel, then measure the self-impedance mentioned above, and then complete the matching network according to steps 3 to 6 After determining all the network values in the matching network, the surface acoustic wave device is connected to the matching channel by adjusting the switch, so as to verify the matching result. Therefore, only one matching device is needed to complete the load impedance matching process for different surface acoustic wave devices. Compared with the existing technology, it avoids the disassembly of multiple hardware in the whole process, and can design different passive load impedance matching networks for the two ports, and flexibly handle the two ports to achieve impedance matching at the same time The center point reduces the reflected wave on the transmission line and improves the transmission efficiency and quality of the surface acoustic wave signal.

It should be noted that: the embodiment of a load impedance matching device and matching method provided in the above embodiment for load impedance matching is only used as an illustration of the actual application of the matching device and matching method, and the above-mentioned The matching device and the matching method are used in other application scenarios, and the specific implementation process thereof is similar to the above-mentioned embodiment, and will not be repeated here.

The serial numbers in the above embodiments are for description only, and do not represent the sequence of the components during assembly or use.

The above description is only an embodiment of the present invention, and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention Inside.

Claims (6)

1. a load impedance coalignment, is characterized in that, described load impedance coalignment, comprising:

SAW (Surface Acoustic Wave) device adapted seat, one end of described SAW (Surface Acoustic Wave) device adapted seat is connected with port one match circuit unit, the other end of described SAW (Surface Acoustic Wave) device adapted seat is connected with port two match circuit unit, described port one match circuit unit is connected with the first joint, is connected with the second joint at described port two match circuit unit;

Wherein, described SAW (Surface Acoustic Wave) device adapted seat is connected with described port one match circuit unit by the first single-pole double-throw switch (SPDT), and described SAW (Surface Acoustic Wave) device adapted seat is connected with described port two match circuit unit by the second single-pole double-throw switch (SPDT);

Be provided with the 3rd single-pole double-throw switch (SPDT) between described port one match circuit unit and described first joint, between described port two match circuit unit and described second joint, be provided with the 4th single-pole double-throw switch (SPDT).

2. load impedance coalignment according to claim 1, is characterized in that, described SAW (Surface Acoustic Wave) device adapted seat, comprising:

Be provided with the In port be connected with acoustic wave device input pin to be measured in one end of described SAW (Surface Acoustic Wave) device adapted seat, be provided with the Out port be connected with acoustic wave device output pin to be measured at the other end of described SAW (Surface Acoustic Wave) device adapted seat.

3. load impedance coalignment according to claim 1, is characterized in that, described port one match circuit unit, comprising:

Electric capacity C11, inductance L 11, inductance L 12;

Wherein, one end of described inductance L 11 is connected with one end of described electric capacity C11, the other end ground connection of described inductance L 11, one end of described inductance L 12 is connected with the other end of described electric capacity C11, the other end ground connection of described inductance L 12, one end of described electric capacity C11 is connected with described first single-pole double-throw switch (SPDT), and the other end of described electric capacity C11 is connected with described 3rd single-pole double-throw switch (SPDT).

4. load impedance coalignment according to claim 1, is characterized in that, described port two match circuit unit, comprising:

Electric capacity C21, inductance L 21, inductance L 22;

Wherein, one end of described inductance L 21 and one end of described inductance L 22 are connected to one end of described electric capacity C21 jointly, the other end of described inductance L 21 is connected with described second single-pole double-throw switch (SPDT), the other end ground connection of described inductance L 22, the other end of described electric capacity C21 is connected with described 4th single-pole double-throw switch (SPDT).

5. a load impedance matching process, is characterized in that, described load impedance matching process, comprising:

Step one, is connected to the port of network analyzer by transmission line by the load impedance coalignment described in claim 1;

Step 2, SAW (Surface Acoustic Wave) device to be measured is placed in the SAW (Surface Acoustic Wave) device adapted seat in described load impedance coalignment, regulate the state of the first single-pole double-throw switch (SPDT), the second single-pole double-throw switch (SPDT), the 3rd single-pole double-throw switch (SPDT), the 4th single-pole double-throw switch (SPDT), make described SAW (Surface Acoustic Wave) device access to be measured not mate passage;

Step 3, measures the impedance of described SAW (Surface Acoustic Wave) device own;

Step 4, in conjunction with matching network structure chart, builds passive impedance matching network;

Step 5, determines passive impedance matching network value;

Step 6, determines all passive load matching network values being positioned at described load impedance coalignment middle port one and port two, builds the load matching circuit associated with port two with described port one;

Step 7, regulates the state of described first single-pole double-throw switch (SPDT), the second single-pole double-throw switch (SPDT), the 3rd single-pole double-throw switch (SPDT), the 4th single-pole double-throw switch (SPDT), by described SAW (Surface Acoustic Wave) device access coupling passage to be measured, completes load matched.

6. load impedance matching process according to claim 5, is characterized in that, describedly determines passive impedance matching network value, comprising:

According to formula one and formula two, in conjunction with Smith's matching track figure determination passive impedance matching network value;

$L_{match}=\frac{1}{h\&times;Y_0\&times;\mathrm{\&omega;}}=\frac{1}{h\&times;Y_0\&times;2\mathrm{\&pi;}f},$ Formula one

$C_{match}=\frac{1}{h\&times;Z_0\&times;\mathrm{\&omega;}}=\frac{1}{h\&times;Z_0\&times;2\mathrm{\&pi;}f},$ Formula two

Wherein, h is arc locus length to be matched, Z ₀for vector network analyzer line characteristic impedance, f is center frequency of acoustic surface wave device, L _matchfor coupling inductance value, C _matchfor matching capacitance value.