CN103647131A - Method for improving microwave circuit coupling degree fluctuation and microwave circuit - Google Patents

Abstract

The invention discloses a method for improving microwave circuit coupling degree fluctuation and a microwave circuit, relating to a microwave communication field. According to the microwave circuit prepared according to the method, when a transmission line has an over-etching or under-etching error, influence on the coupling degree of the microwave circuit can be offset, thus the influence on the coupling degree performance of the microwave circuit by a processing error is reduced. The method comprises a step of determining a transmission line with a minimum line width and calculating the influence trend of the transmission line on the coupling degree of the microwave circuit, a step of marking transmission lines with influence trends opposite to the above influence trend on the coupling degree of the microwave circuit as object transmission lines, and a step of using a group of alternative transmission lines in parallel connection to replace the object transmission lines, wherein the parallel impedance of the plurality of object transmission lines is consistent with the object transmission line impedance.

Description

A kind of method and microwave circuit that improves the fluctuation of the microwave circuit degree of coupling

Technical field

The present invention relates to microwave communication field, relate in particular to a kind of method and microwave circuit that improves the fluctuation of the microwave circuit degree of coupling.

Background technology

Microwave circuit is to be operated in microwave band and millimeter wave band, has a kind of circuit of specific function.According to the difference of its circuit structure and function, microwave circuit can be specially, for example: electric bridge, power divider, directional coupler etc. circuit.

As the component part in microwave circuit, the performance of transmission line can produce larger impact to microwave circuit.Wherein, according to the difference of kind, transmission line can be further microwave line, strip line, coaxial line and waveguide wire etc.

As a rule, transmission line can directly be formed on the substrate of microwave circuit by means of typography, thereby has greatly simplified the preparation process of microwave circuit.

Take transmission line as microwave line or belt shape line be example, as shown in Figure 1, Fig. 1 is the generalized section of microwave line or belt shape line.Wherein its impedance of microwave line or belt shape line is mainly the live width by the conductor layer live width w(radiation patch that namely conductor layer forms), conductor layer to reference to ground distance h (or h ₁, h ₂) and the parameter such as dielectric material ε r determine.That is to say, by controlling above-mentioned relevant parameter, can determine the impedance of microwave line or belt shape line.

Yet inventor finds that in prior art, at least there are the following problems: because typography over etching may occur or owes the situation of etching, therefore just caused the transmission line forming to occur mismachining tolerance.Corresponding to Fig. 1, due to the over etching of typography or owe etching, may cause the conductor layer live width w of microwave line or belt shape line to occur deviation, and then cause again the variation of microwave line or belt shape line impedence, finally caused that microwave circuit degree of coupling performance worsens.And the situation of the microwave circuit degree of coupling that prior art processes cannot be avoided causing because of mismachining tolerance fluctuation occurs.

Summary of the invention

Embodiments of the invention provide a kind of method and microwave circuit that improves the fluctuation of the microwave circuit degree of coupling, the impact that its transmission line of the microwave circuit of preparing according to the method produces the microwave circuit degree of coupling when over etching occurring or owe lithography error can be cancelled out each other, thereby reduces the impact of mismachining tolerance on microwave circuit degree of coupling performance.

For solving the problems of the technologies described above, embodiments of the invention adopt following technical scheme:

A method of improving the fluctuation of the microwave circuit degree of coupling, described microwave circuit comprises some transmission lines, described method comprises:

Determine the transmission line of live width minimum in described microwave circuit, the transmission line that calculates described live width minimum is the trend that affects on the described microwave circuit degree of coupling at over etching or in owing etching process;

Calculate in described microwave circuit other transmission line at over etching or the trend that affects on the described microwave circuit degree of coupling in owing etching process, by least one, at over etching or in owing etching process, the trend that affects of the described microwave circuit degree of coupling is labeled as to object transmission line at over etching or in owing etching process to the contrary transmission line of the trend that affects of the described microwave circuit degree of coupling with the transmission line of described live width minimum;

Utilize more than the one group alternative transmission line being connected in parallel to replace described object transmission line, the impedance that more than one group described alternative transmission line is connected in parallel and the impedance phase of described object transmission line with.

In the possible implementation of the first, when described alternative transmission line is microstrip line, between the impedance of described microstrip line and conductor layer live width, meet:

$Z_0=\left\{\begin{array}{c}\frac{60}{\sqrt{{\mathrm{\ϵ}}_e}}\ln (\frac{8d}{w}+\frac{w}{4d}),w/d\≤1\\ \frac{120\mathrm{\π}}{\sqrt{{\mathrm{\ϵ}}_e}[\frac{w}{d}+1.393+0.667\ln (\frac{w}{d}+1.444)]},w/d\≥1\end{array}\right.;$

Z ₀: the resistance value of described microstrip line; W: the conductor layer live width of described microstrip line; D: the conductor layer in described microstrip line and with reference to the distance between ground; ε e: the effective dielectric constant of described microstrip line, the effective dielectric constant of described microstrip line meets:

${\mathrm{\ϵ}}_e=\frac{{\mathrm{\ϵ}}_r+1}{2}+\frac{{\mathrm{\ϵ}}_r-1}{2}\frac{1}{\sqrt{1+12d/w}};$

ε r: the relative dielectric constant of described microstrip line dielectric substrate.

In the possible implementation of the second, when described alternative transmission line is strip line, between the impedance of described strip line and conductor layer live width, meet:

$Z_0=\frac{30\mathrm{\π}}{\sqrt{{\mathrm{\ϵ}}_r}}\frac{b}{w_e+0.441b};$

Z ₀: the resistance value of described strip line; B: described strip line is with reference to ground and with reference to the distance between ground; ε r: the relative dielectric constant of described strip line dielectric substrate; We: the effective width of described stripline conductors layer, the effective width of described strip line center conductor layer meets:

$\frac{w_e}{b}=\frac{w}{b}-\left\{\begin{array}{c}0,\frac{w}{b}>0.35\\ {(0.35-w/b)}^2,\frac{w}{b}<0.35\end{array}\right.;$

W: the conductor layer live width of described strip line.

In the third possible implementation, while including the transmission line of two kinds of different live widths in described microwave circuit, described method is specially:

The transmission line of live width maximum is labeled as to object transmission line;

Utilize more than the one group alternative transmission line being connected in parallel to replace described object transmission line, the impedance that more than one group described alternative transmission line is connected in parallel and the impedance phase of described object transmission line with.

In the 4th kind of possible implementation, when described microwave circuit is two branch directional couplers, while including the transmission line of three kinds of different live widths in described two branch directional couplers, described method is specially:

The transmission line of the live width maximum except impedance matching line is labeled as to object transmission line;

Utilize more than the one group alternative transmission line being connected in parallel to replace described object transmission line, the impedance that more than one group described alternative transmission line is connected in parallel and the impedance phase of described object transmission line with.

In the 5th kind of possible implementation, when described microwave circuit is three branch directional couplers, while including the transmission line of four kinds of different live widths in described three branch directional couplers, described method is specially:

The transmission line of the live width maximum except impedance matching line is labeled as to object transmission line;

Utilize more than the one group alternative transmission line being connected in parallel to replace described object transmission line, the impedance that more than one group described alternative transmission line is connected in parallel and the impedance phase of described object transmission line with.

In the 6th kind of possible implementation, when described microwave circuit is decile Wilkinson power divider not, when described not decile Wilkinson power divider includes the transmission line of five kinds of different live widths, described method is specially:

The transmission line of the live width maximum except impedance matching line is labeled as to object transmission line;

Utilize more than the one group alternative transmission line being connected in parallel to replace described object transmission line, the impedance that more than one group described alternative transmission line is connected in parallel and the impedance phase of described object transmission line with.

On the other hand, the present invention also provides a kind of microwave circuit, and described microwave circuit comprises some transmission lines, and described microwave circuit is prepared according to method described above.

A kind of method and microwave circuit that improves the fluctuation of the microwave circuit degree of coupling that the embodiment of the present invention provides, the method comprises the following steps: determine the transmission line of live width minimum and calculate the affect trend of this transmission line on the microwave circuit degree of coupling; By with on the trend that affects of the microwave circuit degree of coupling and above-mentionedly affect the transmission line that trend is contrary and be labeled as object transmission line; Utilize more than one group alternative transmission line replacement object transmission line and the many alternative transmission line parallel impedances that are connected in parallel consistent with object transmission line impedence.By above-mentioned steps, can make the transmission line of microwave circuit on the impact of microwave circuit degree of coupling generation, can cancel out each other when over etching occurring or owe lithography error, thereby reduce the impact of mismachining tolerance on microwave circuit degree of coupling performance.

Accompanying drawing explanation

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, to the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skills, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.

Fig. 1 is the generalized section of microwave line or belt shape line;

A kind of method flow diagram that improves the fluctuation of the microwave circuit degree of coupling that Fig. 2 provides for the embodiment of the present invention;

Fig. 3 is each arm admittance schematic diagram of two branch directional couplers;

Fig. 4 is a kind of electrical block diagram of prior art two branch directional couplers;

Fig. 5 is two branch directional coupler degree of coupling simulation results shown in Fig. 4;

The electrical block diagram of two branch directional couplers that Fig. 6 generates after processing for the method that provides according to the embodiment of the present invention;

Fig. 7 is two branch directional coupler degree of coupling simulation results shown in Fig. 6;

Fig. 8 is each arm admittance schematic diagram of three branch directional couplers;

Fig. 9 is a kind of electrical block diagram of prior art three branch directional couplers;

Figure 10 is three branch directional coupler degree of coupling simulation results shown in Fig. 9;

The electrical block diagram of three branch directional couplers that Figure 11 generates after processing for the method that provides according to the embodiment of the present invention;

Figure 12 is three branch directional coupler degree of coupling simulation results shown in Figure 11;

Figure 13 is each section of characteristic impedance schematic diagram of decile Wilkinson power divider not;

Figure 14 is the not electrical block diagram of decile Wilkinson power divider of a kind of prior art;

Figure 15 is the not decile Wilkinson power divider degree of coupling simulation result shown in Figure 14;

The electrical block diagram of the not decile Wilkinson power divider that Figure 16 generates after processing for the method that provides according to the embodiment of the present invention;

Figure 17 is the not decile Wilkinson power divider degree of coupling simulation result shown in Figure 16.

Embodiment

Embodiments of the invention provide a kind of method of improving the fluctuation of the microwave circuit degree of coupling, the impact that its transmission line of the microwave circuit of preparing according to the method produces the microwave circuit degree of coupling when over etching occurring or owe lithography error can be cancelled out each other, thereby reduces the impact of mismachining tolerance on microwave circuit degree of coupling performance.

In below describing, in order to illustrate rather than in order limiting, to have proposed the detail such as particular system structure, interface, technology, to thoroughly cut, understand the present invention.Yet, not it will be clear to one skilled in the art that in there is no other embodiment of these details and can realize the present invention yet.In other situation, omit the detailed description to well-known device, circuit and method, in order to avoid unnecessary details hinders description of the invention.

Below in conjunction with following accompanying drawing, the embodiment of the present invention is described in detail.

The embodiment of the present invention provides a kind of method of improving the fluctuation of the microwave circuit degree of coupling, and as shown in Figure 2, the method comprises:

Step S101: determine the transmission line of live width minimum in microwave circuit, the transmission line of calculating live width minimum is the trend that affects on the microwave circuit degree of coupling at over etching or in owing etching process;

It should be noted that, in the preparation process of microwave circuit, when the live width of its transmission line is because of over etching or owe etching while there is mismachining tolerance, this mismachining tolerance can cause that the transmission line impedance of generation changes.

Concrete, with existing PCB typography, the be generally ± 2mil of mismachining tolerance size of generation.The transmission line of the different live widths that comprise for microwave circuit, for example: the transmission line that standard live width is 4mil, and the standard live width transmission line that is 48mil; Obviously, this mismachining tolerance is comparatively violent to the thinner transmission line effects of live width, and comparatively mild for the thicker transmission line effects of live width.(it should be noted that, above-mentioned live width size is only for giving an example, rather than the further restriction to transmission line.）

That is to say, the transmission line of live width minimum its impedance variation when mismachining tolerance occurs is the most violent, and then the fluctuation that the microwave circuit degree of coupling is produced is also maximum.Therefore,, in the method providing in the embodiment of the present invention, the transmission line of first determining the transmission line of live width minimum and calculating this live width minimum is the trend that affects on the microwave circuit degree of coupling at over etching or in owing etching process.

Step S102: calculate in microwave circuit other transmission line at over etching or the trend that affects on the microwave circuit degree of coupling in owing etching process, at over etching or in owing etching process, the trend that affects of the microwave circuit degree of coupling is labeled as to object transmission line at over etching or in owing etching process to the contrary transmission line of the trend that affects of the microwave circuit degree of coupling with the transmission line of live width minimum by least one;

On the basis of completing steps S101, continue to calculate in microwave circuit other transmission line at over etching or the trend that affects on the microwave circuit degree of coupling in owing etching process.

It should be noted that, at over etching or owe etching while occurring, transmission line is because live width mismachining tolerance all can exert an influence to the fluctuation of the microwave circuit degree of coupling.Further, the transmission line that obtains live width minimum after step S101 is affecting after trend the microwave circuit degree of coupling at over etching or in owing etching process, continuation is calculated other transmission line in microwave circuit, thereby finds at over etching or in owing etching process on the transmission line of the trend that affects of the microwave circuit degree of coupling and step S101 live width minimum the transmission line contrary on the trend that affects of the microwave circuit degree of coupling at over etching or in owing etching process.Then, at least one transmission line that meets above-mentioned condition is labeled as to object transmission line.As a kind of optional execution mode, the many transmission lines with identical live width that meet above-mentioned condition are all labeled as to object transmission line.

Step S103: utilize more than the one group alternative transmission line being connected in parallel to replace object transmission line, the impedance phase of more than one group impedance that alternative transmission line is connected in parallel and object transmission line together.

On the basis of completing steps S102, mark after object transmission line, utilize alternative transmission line to carry out equivalent substitution to object transmission line.

Concrete, utilize more than the one group alternative transmission line being connected in parallel to replace object transmission line.Wherein, for keeping substituting the equivalent substitution between transmission line and object transmission line, more than the one group impedance that alternative transmission line is connected in parallel should be same with the impedance phase of object transmission line.It should be noted that, because the impedance that more than one group alternative transmission line is connected in parallel should be same with the impedance phase of object transmission line, therefore any its resistance value of alternative transmission line certainly will be greater than its resistance value of object transmission line.

It should be noted that, according to the quantity of the alternative transmission line of the resistance value of object transmission line and setting, can calculate the impedance that substitutes transmission line, and then calculate the live width that substitutes transmission line.For instance, when alternative transmission line is microstrip line, between the resistance value of this microstrip line and microstrip line conductor layer live width, meet:

$Z_0=\left\{\begin{array}{c}\frac{60}{\sqrt{{\mathrm{\&epsiv;}}_e}}\ln (\frac{8d}{w}+\frac{w}{4d}),w/d\&le;1\\ \frac{120\mathrm{\&pi;}}{\sqrt{{\mathrm{\&epsiv;}}_e}[\frac{w}{d}+1.393+0.667\ln (\frac{w}{d}+1.444)]},w/d\&GreaterEqual;1\end{array}\right.;---(1-1)$

Wherein, Z ₀: the resistance value of microstrip line; W: the conductor layer live width of microstrip line; D: the conductor layer in microstrip line and with reference to the distance between ground; ε e: the effective dielectric constant of microstrip line, the effective dielectric constant of microstrip line meets:

${\mathrm{\&epsiv;}}_e=\frac{{\mathrm{\&epsiv;}}_r+1}{2}+\frac{{\mathrm{\&epsiv;}}_r-1}{2}\frac{1}{\sqrt{1+12d/w}};---(1-2)$

ε r: the relative dielectric constant of microstrip line dielectric substrate.That is to say, in the definite situation of the resistance value of microstrip line, by above-mentioned formula (1-1), (1-2), can calculate the conductor layer live width w in microstrip line.

And when alternative transmission line is strip line, between the impedance of strip line and conductor layer live width, meet:

$Z_0=\frac{30\mathrm{\&pi;}}{\sqrt{{\mathrm{\&epsiv;}}_r}}\frac{b}{w_e+0.441b};---(2-1)$

Z ₀: the resistance value of strip line; B: strip line is with reference to ground and with reference to the distance between ground; ε r: the relative dielectric constant of strip line dielectric substrate; We: the effective width of stripline conductors layer, the effective width of strip line center conductor layer meets:

$\frac{w_e}{b}=\frac{w}{b}-\left\{\begin{array}{c}0,\frac{w}{b}>0.35\\ {(0.35-w/b)}^2,\frac{w}{b}<0.35\end{array}\right.;---(2-2)$

W: the conductor layer live width of strip line.Same, in the definite situation of the resistance value of strip line, by above-mentioned formula (2-1), (2-2), can calculate the conductor layer live width w of strip line.

Same, for example, for the alternative transmission line of other kind: coaxial line and waveguide wire etc., in the definite situation of its impedance, all can calculate corresponding line width values, at this, do not repeat.

It should be noted that, no matter substitute transmission line and adopt which kind of transmission line, those skilled in the art can know know be, the resistance value that substitutes transmission line is greater than the resistance value of object transmission line, and the live width that substitutes transmission line certainly will be less than the live width of object transmission line (in the situation that conversion does not occur other parameter).That is to say, in the equivalent substitution process of step S103, be in fact the live width (live width that substitutes transmission line is less than original object transmission line live width) that has reduced object transmission line.Therefore, substituting the live width of transmission line and the live width of minimum feature transmission line comparatively approaches between the two.

On the other hand, according to step S102, can know, object transmission line and minimum feature transmission line are at over etching or owe etching process while occurring, and both are contrary on the trend that affects of the microwave circuit degree of coupling; And in step S103, the object transmission line that substituted transmission line equivalent substitute, this equivalent substitute process can't change the affect trend of corresponding transmission line on the microwave circuit degree of coupling.Therefore substitute transmission line with object transmission line at over etching or in owing etching process the trend that affects on the microwave circuit degree of coupling be identical.Can infer out thus, substitute transmission line with minimum feature transmission line at over etching or be contrary on the trend that affects of the microwave circuit degree of coupling while owing etching process generation.

In sum, after completing steps S103, at over etching or in owing etching process, the trend that affects on the microwave circuit degree of coupling is contrary to the transmission line that substitutes transmission line and minimum feature, and the transmission line live width of alternative transmission line and minimum feature is comparatively approaching again.Therefore, when mismachining tolerance occurs, substitute transmission line that transmission line can effectively offset minimum feature to the impact of the microwave circuit degree of coupling at over etching or the impact on the microwave circuit degree of coupling in owing etching process, thereby also just improved the microwave circuit degree of coupling fluctuation situation causing because of mismachining tolerance.

Further, in conjunction with several concrete microwave circuit structures, detailed a kind of method of improving the fluctuation of the microwave circuit degree of coupling that above-described embodiment provides described once.

As a kind of embodiment of the present invention, take microwave circuit as two branch directional couplers be example.The function of two branch directional couplers is that input signal is divided into two-way output according to certain power proportions.As shown in Figure 3, Fig. 3 is each arm admittance schematic diagram of two branch directional couplers.According to microwave circuit transmission line theory, can obtain two its ideal orientations of branch line directional coupler shown in Fig. 3 and matching condition and meet relational expression (3-1) (wherein, U ₁for input voltage; U ₃, U ₄for output voltage); Two output voltage U that output port is corresponding ₃, U ₄ratio meets relational expression (3-2).

H ²=1+G ² (3-1)；

U ₃/U ₄=2G/(1-G ²+H ²) (3-2)；

Further, as shown in Figure 4, Fig. 4 has provided a kind of structural representation of prior art two branch directional coupler circuit.Wherein, this two branch directional coupler comprises four port one 1a, 11b, 11c, 11d; Port one 1a is input port, and port one 1c, port one 1b are output port, and the power division ratio of output signal is come corresponding definite according to the impedance of two branch directional coupler transmission lines.Port one 1b is isolated port, there is no in theory signal output.

In addition, in this two branch directional coupler, also include the transmission line (supposing that the transmission line in this two branch directional coupler is microstrip line) of three kinds of different live widths.For instance, specifically comprise: microstrip line that two conductor layer live widths are w12 12, two microstrip lines that conductor layer live width is w13 13 and four impedance matching lines 14.

Suppose that this two branch directional coupler has adopted one side PCB structure, the PCB back side retains complete Copper Foil as the reference ground of electric bridge; PCB front Copper Foil forms the required figure of electric bridge by etching mode.Using the port one 1a in this two branch directional coupler as input port, using 11c, 11d port as output port, connect antenna even load device, also can be by the working condition of connector or wireline test output port.

Further this two branch directional couplers power ratio of hypothesis is 8dB, and voltage ratio is 4dB.According to formula (3-2), can calculate U ₄/ U ₃=2.5.On the other hand, in conjunction with formula (3-1) and other setup parameter, such as substrate medium etc., can be calculated the conductor layer live width w12=4mil of microstrip line 12, corresponding resistance value Z12=125 Ω; The conductor layer live width w13=48mil of microstrip line 13, corresponding resistance value Z13=46.4 Ω.

Suppose in the course of processing, because deviation appears in the conductor layer live width of crossing etching or owing etching microstrip line, the mismachining tolerance of this live width is ± 2mil.Can calculate, within the scope of the microwave operational frequencies of 1800MHz～2100MHz, this two branch directional couplers which couple degree range of tolerable variance is ± 0.75dB that its degree of coupling simulation result as shown in Figure 5.

For improving the degree of coupling fluctuation situation of two branch directional couplers, the method providing according to the embodiment of the present invention is below adjusted the circuit structure of two branch directional couplers.

Wherein, for two branch directional couplers of prior art, after getting rid of impedance matching line, confirmable, the transmission line of minimum feature is microstrip line 12, and object transmission line is microstrip line 13.Therefore, two branch directional coupler microstrip lines 13 of prior art being carried out to equivalence replaces.It should be noted that, those skilled in the art can utilize simulated program to determine in prior art two branch directional couplers, which root transmission line, for object transmission line, is not described in detail at this.

The structural representation of the two branch directional coupler circuit that as shown in Figure 6, Fig. 6 generates after processing for the method for utilizing the embodiment of the present invention and providing.Wherein, this two branch directional coupler utilizes one group of three microstrip line 13 ' substitute the microstrip line 13 of prior art two branch directional couplers in the mode that is connected in parallel, and all the other transmission lines are constant.

Can be calculated, the resistance value of microstrip line 13 ' correspondence is Z13 '=139.2 Ω (one group of three microstrip lines 13 ' resistance value after being connected in parallel equals the resistance value of microstrip line 13).And further according to formula (1-1), (1-2) can calculate, microstrip line 13 ' conductor layer live width w13 '=2.6mil.Can find, by equivalent substitution, microstrip line 13 ' conductor layer live width w13 ' become comparatively approaching with the conductor layer live width w12 of microstrip line 12.Now carry out again the impact of calculating processing error on two branch directional coupler which couple degree.

Same, suppose in the course of processing, because deviation appears in mistake etching or the conductor layer live width of owing etching microstrip line, the mismachining tolerance of this live width is ± 2mil.Can calculate, within the scope of the microwave operational frequencies of 1800MHz～2100MHz, this two branch directional couplers which couple degree range of tolerable variance is ± 0.2dB that its degree of coupling simulation result as shown in Figure 7.

So far, by Fig. 5 and Fig. 7, can find, two branch directional coupler circuit after the method that provides by the embodiment of the present invention is processed, it is improved because of the degree of coupling fluctuation situation that mismachining tolerance causes.

As another kind of embodiment of the present invention, take microwave circuit as three branch directional couplers be example.The function of three branch directional couplers is that input signal is divided into two-way output according to certain power proportions.As shown in Figure 8, Fig. 8 is each arm admittance schematic diagram of three branch directional couplers.According to microwave circuit transmission line theory, can obtain three its ideal orientations of branch line directional coupler shown in Fig. 8 and matching condition and meet relational expression (4-1) (wherein, U ₁for input voltage; U ₃, U ₄for output voltage); Two output voltage U that output port is corresponding ₃, U ₄ratio meets relational expression (4-2).

G ₂=2G ₁H ²/(1+G ₁ ²) (4-1)；

U ₃/U ₄=[2G ₁H ²+G ₂(1-G ₁ ²)]/2(H ²-G ₁G ₂) (4-2)；

Further, as shown in Figure 9, Fig. 9 has provided a kind of structural representation of prior art three branch directional coupler circuit.Wherein, this three branch directional coupler comprises four port 21a, 21b, 21c, 21d; Port 21a is input port, and port 21c, port 21d are output port, and the power division ratio of output signal is come corresponding definite according to the impedance of three branch directional coupler transmission lines.Port 21b is isolated port, there is no in theory signal output.

In this three branch directional coupler, also include the transmission line (supposing that the transmission line in this three branch directional coupler is microstrip line) of four kinds of different live widths.For instance, specifically comprise: microstrip line that conductor layer live width is w22 22, two microstrip lines that conductor layer live width is w23 23, four microstrip lines that conductor layer live width is w24 24 and four impedance matching lines 25.

Than two branch directional couplers, the bandwidth of three branch directional couplers is wider.Suppose that this three branch directional coupler has adopted one side PCB structure, the PCB back side retains complete Copper Foil as the reference ground of electric bridge; PCB front Copper Foil forms the required figure of electric bridge by etching mode.Using the port 21a in this three branch directional coupler as input port, using 21c, 21d port as output port, connect antenna even load device, also can be by the working condition of connector or wireline test output port.

The coupling condition of supposing this three branch directional coupler is 3dB.According to formula (4-1) and formula (4-2), further get H=2 ^1/2g ².On the other hand, in conjunction with other setup parameter, such as substrate medium etc., can be calculated the conductor layer live width w22=43mil of microstrip line 22, corresponding resistance value Z22=50 Ω; The conductor layer live width w23=6mil of microstrip line 23, corresponding resistance value Z23=121 Ω; The conductor layer live width w24=63.5mil of microstrip line 24, corresponding resistance value Z24=35.4 Ω.

Suppose in the course of processing, because deviation appears in the conductor layer live width of crossing etching or owing etching microstrip line, the mismachining tolerance of this live width is ± 2mil.Can calculate, within the scope of the microwave operational frequencies of 1710MHz～2170MHz, these three branch directional couplers circuit, 2 degree of coupling ranges of tolerable variance are ± 0.55dB that its degree of coupling simulation result as shown in figure 10.

For improving the degree of coupling fluctuation situation of three branch directional couplers, the method providing according to the embodiment of the present invention is below adjusted the circuit structure of three branch directional couplers.

Wherein, for three branch directional couplers of prior art, after getting rid of impedance matching line, be confirmablely, the transmission line of minimum feature is microstrip line 23, and object transmission line is microstrip line 24(, removes the transmission line of the live width maximum outside impedance matching line).Therefore, two branch directional coupler microstrip lines 24 of prior art being carried out to equivalence replaces.Same, those skilled in the art can utilize simulated program to determine in prior art three branch directional couplers, which root transmission line, for object transmission line, is not described in detail at this.

The structural representation of the three branch directional coupler circuit that as shown in figure 11, Figure 11 generates after processing for the method for utilizing the embodiment of the present invention and providing.Wherein, this three branch directional coupler utilizes one group of three microstrip line 24 ' substitute the microstrip line 24 of prior art three branch directional couplers in the mode that is connected in parallel, and all the other transmission lines are constant.

Can be calculated, the resistance value of microstrip line 24 ' correspondence is Z24 '=106.2 Ω (one group of three microstrip lines 24 ' resistance value after being connected in parallel equals the resistance value of microstrip line 24).And further according to formula (1-1), (1-2) can calculate, microstrip line 24 ' conductor layer live width w24 '=8.1mil.Can find, by equivalent substitution, microstrip line 24 ' conductor layer live width w24 ' become comparatively approaching with the conductor layer live width w23 of microstrip line 23.Now carry out again the impact of calculating processing error on three branch directional coupler which couple degree.

Same, suppose in the course of processing, because deviation appears in mistake etching or the conductor layer live width of owing etching microstrip line, the mismachining tolerance of this live width is ± 2mil.Can calculate, within the scope of the microwave operational frequencies of 1710MHz～2170MHz, this three branch directional couplers which couple degree range of tolerable variance is ± 0.04dB that its degree of coupling simulation result as shown in figure 12.

So far, by Figure 10 and Figure 12, can find, three branch directional coupler circuit after the method that provides by the embodiment of the present invention is processed, it is improved because of the degree of coupling fluctuation situation that mismachining tolerance causes.

As another kind of embodiment of the present invention, take microwave circuit for decile Wilkinson power divider be not example.The function of decile Wilkinson power divider is not that input signal is divided into two-way output according to certain power proportions.As shown in figure 13, Figure 13 is each section of characteristic impedance schematic diagram of decile Wilkinson power divider not.According to microwave circuit transmission line theory, can obtain its each section of characteristic impedance of not decile Wilkinson power divider shown in Figure 13 and meet respectively relational expression (5-1) (5-2) (5-3) (5-4).(wherein, P ₂, P ₃be respectively two power outputs that port is corresponding; And P ₃/ P ₂=K ²)

Z ₀₃=Z ₀[(1+K ²)/K ³] ^1/2 (5-1)

Z ₀₂=K ²Z ₀₃=Z ₀[K(1+K ²)] ^1/2 (5-2)

Z _2b=Z ₀(K) ^1/2 (5-3)

Z _3b=Z ₀/(K) ^1/2 (5-4)

Further, as shown in figure 14, Figure 14 has provided the not structural representation of decile Wilkinson power divider circuits of a kind of prior art.Wherein, this not decile Wilkinson power divider comprise three port 31a, 31b, 31c; Port 31a is input port, and port 31b, 31c are output port, and the power division ratio basis of the output signal not impedance of decile Wilkinson power divider transmission line is come corresponding definite.

This does not also include the transmission line (suppose this not the transmission line in decile Wilkinson power divider be microstrip line) of five kinds of different live widths in decile Wilkinson power divider.For instance, specifically comprise: microstrip line that conductor layer live width is w32 32, microstrip line that conductor layer live width is w33 33, the branch impedance matched line 34 of port 31a are, the branch impedance matched line 36 of the branch impedance matched line 35 of port 31b, port 31c.

Wherein, decile Wilkinson power divider has not adopted one side PCB structure, and the PCB back side retains complete Copper Foil as the reference ground of electric bridge; PCB front Copper Foil forms the required figure of electric bridge by etching mode.Using this not the port 31a in decile Wilkinson power divider as input port, by 31b, 31c port, be that output port connects antenna even load device, also can be by the working condition of connector or wireline test output port.

Suppose this not the coupling condition of decile Wilkinson power divider be 4dB.According to formula (5-1), (5-2), (5-3), (5-4), further combined with other setup parameter, such as substrate medium etc., can be calculated the conductor layer live width w32=47mil of microstrip line 32, corresponding resistance value Z32=47 Ω; The conductor layer live width w33=5.7mil of microstrip line 33, corresponding resistance value Z33=117 Ω.In addition, the branch impedance matched line 34 of port 31a is that the branch circuit impedance of 50 Ω feed transmission lines, the branch impedance matched line 35 of port 31b and the branch impedance matched line 36 of port 31c is respectively 40 Ω and 62.8 Ω.

Same, suppose in the course of processing, because deviation appears in mistake etching or the conductor layer live width of owing etching microstrip line, the mismachining tolerance of this live width is ± 2mil.Can calculate, within the scope of the microwave operational frequencies of 1710MHz～2170MHz, this not decile Wilkinson power divider degree of coupling range of tolerable variance be ± 0.5dB that its degree of coupling simulation result as shown in figure 15.

For improving the degree of coupling fluctuation situation of decile Wilkinson power divider not, the method providing according to the embodiment of the present invention is below adjusted the circuit structure of decile Wilkinson power divider not.

Wherein, for the not decile Wilkinson power divider of prior art, after getting rid of impedance matching line, be confirmablely, the transmission line of minimum feature is microstrip line 33, and object transmission line is microstrip line 32(, removes the transmission line of the live width maximum outside impedance matching line).Therefore, the not decile Wilkinson power divider microstrip line 32 of prior art being carried out to equivalence replaces.Same, those skilled in the art can utilize simulated program determine prior art not in decile Wilkinson power divider any root transmission line for object transmission line, at this, be not described in detail.

The structural representation of the not decile Wilkinson power divider circuits that as shown in figure 16, Figure 16 generates after processing for the method for utilizing the embodiment of the present invention and providing.Wherein, this not decile Wilkinson power divider utilize one group of two microstrip line 32 ' substitute the not microstrip line 32 of decile Wilkinson power divider of prior art in the mode that is connected in parallel, and all the other transmission lines are constant.

Can be calculated, the resistance value of microstrip line 32 ' correspondence is Z32 '=94 Ω (one group of two microstrip lines 32 ' resistance value after being connected in parallel equals the resistance value of microstrip line 32).And further according to formula (1-1), (1-2) can calculate, microstrip line 32 ' conductor layer live width w32 ' become comparatively approaching with the conductor layer live width w33 of microstrip line 33.Now come again calculating processing error on the not impact of the decile Wilkinson power divider degree of coupling.

Suppose in the course of processing, because deviation appears in the conductor layer live width of crossing etching or owing etching microstrip line, the mismachining tolerance of this live width is ± 2mil.Can calculate, within the scope of the microwave operational frequencies of 1710MHz～2170MHz, this not decile Wilkinson power divider degree of coupling range of tolerable variance be ± 0.25dB that its degree of coupling simulation result as shown in figure 17.

So far, by Figure 15 and Figure 17, can find, the not decile Wilkinson power divider after the method that provides by the embodiment of the present invention is processed, it is improved because of the degree of coupling fluctuation situation that mismachining tolerance causes.

In sum, those skilled in the art are confirmable: after utilizing method that the embodiment of the present invention provides to process microwave circuit, can make the transmission line of microwave circuit when over etching occurring or owe lithography error, the impact of microwave circuit degree of coupling generation be cancelled out each other, thereby reduce the impact of mismachining tolerance on microwave circuit degree of coupling performance.

In addition, as another kind of embodiment of the present invention, while including the transmission line of two kinds of different live widths in microwave circuit, the method for the embodiment of the present invention is specially:

The transmission line of live width maximum is labeled as to object transmission line; Utilize more than the one group alternative transmission line being connected in parallel to replace object transmission line, the impedance phase of more than one group impedance that alternative transmission line is connected in parallel and object transmission line together.

Wherein, the mentioned method of improving the fluctuation of the microwave circuit degree of coupling in this embodiment, it can, with reference to the description in above-mentioned embodiment, not repeat at this equivalent substitution process of microwave circuit.

A kind of method of improving the fluctuation of the microwave circuit degree of coupling that the embodiment of the present invention provides, the method comprises the following steps: determine the transmission line of live width minimum and calculate the affect trend of this transmission line on the microwave circuit degree of coupling; By with on the trend that affects of the microwave circuit degree of coupling and above-mentionedly affect the transmission line that trend is contrary and be labeled as object transmission line; Utilize more than one group alternative transmission line replacement object transmission line and the many alternative transmission line parallel impedances that are connected in parallel consistent with object transmission line impedence.By above-mentioned steps, can make the transmission line of microwave circuit on the impact of microwave circuit degree of coupling generation, can cancel out each other when over etching occurring or owe lithography error, thereby reduce the impact of mismachining tolerance on microwave circuit degree of coupling performance.

On the other hand, the embodiment of the present invention also provides a kind of microwave circuit, and microwave circuit comprises some transmission lines, and this microwave circuit is prepared according to the mentioned method of above-described embodiment.Wherein, about how processing the microwave circuit that generates the present embodiment, its concrete treatment step can, with reference to the associated description of said method embodiment, not repeat at this.Unique it should be noted that, the microwave circuit structure of mentioning in above-mentioned embodiment and transmission line kind be only for explaining, and do not form the further restriction to the present embodiment.

The above; be only the specific embodiment of the present invention, but protection scope of the present invention is not limited to this, is anyly familiar with those skilled in the art in the technical scope that the present invention discloses; can expect easily changing or replacing, within all should being encompassed in protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of described claim.

Claims (8)

1. a method of improving the fluctuation of the microwave circuit degree of coupling, described microwave circuit comprises some transmission lines, it is characterized in that, described method comprises:

Determine the transmission line of live width minimum in described microwave circuit, the transmission line that calculates described live width minimum is the trend that affects on the described microwave circuit degree of coupling at over etching or in owing etching process;

Calculate in described microwave circuit other transmission line at over etching or the trend that affects on the described microwave circuit degree of coupling in owing etching process, by least one, at over etching or in owing etching process, the trend that affects of the described microwave circuit degree of coupling is labeled as to object transmission line at over etching or in owing etching process to the contrary transmission line of the trend that affects of the described microwave circuit degree of coupling with the transmission line of described live width minimum;

Utilize more than the one group alternative transmission line being connected in parallel to replace described object transmission line, the impedance that more than one group described alternative transmission line is connected in parallel and the impedance phase of described object transmission line with.

2. the method for improving the fluctuation of the microwave circuit degree of coupling according to claim 1, is characterized in that, when described alternative transmission line is microstrip line, between the impedance of described microstrip line and conductor layer live width, meets:

$Z_0=\left\{\begin{array}{c}\frac{60}{\sqrt{{\mathrm{\&epsiv;}}_e}}\ln (\frac{8d}{w}+\frac{w}{4d}),w/d\&le;1\\ \frac{120\mathrm{\&pi;}}{\sqrt{{\mathrm{\&epsiv;}}_e}[\frac{w}{d}+1.393+0.667\ln (\frac{w}{d}+1.444)]},w/d\&GreaterEqual;1\end{array}\right.;$

Z ₀: the resistance value of described microstrip line; W: the conductor layer live width of described microstrip line; D: the conductor layer in described microstrip line and with reference to the distance between ground; ε e: the effective dielectric constant of described microstrip line, the effective dielectric constant of described microstrip line meets:

${\mathrm{\&epsiv;}}_e=\frac{{\mathrm{\&epsiv;}}_r+1}{2}+\frac{{\mathrm{\&epsiv;}}_r-1}{2}\frac{1}{\sqrt{1+12d/w}};$

ε r: the relative dielectric constant of described microstrip line dielectric substrate.

3. the method for improving the fluctuation of the microwave circuit degree of coupling according to claim 1, is characterized in that, when described alternative transmission line is strip line, between the impedance of described strip line and conductor layer live width, meets:

$Z_0=\frac{30\mathrm{\&pi;}}{\sqrt{{\mathrm{\&epsiv;}}_r}}\frac{b}{w_e+0.441b};$

Z ₀: the resistance value of described strip line; B: described strip line is with reference to ground and with reference to the distance between ground; ε r: the relative dielectric constant of described strip line dielectric substrate; We: the effective width of described stripline conductors layer, the effective width of described strip line center conductor layer meets:

$\frac{w_e}{b}=\frac{w}{b}-\left\{\begin{array}{c}0,\frac{w}{b}>0.35\\ {(0.35-w/b)}^2,\frac{w}{b}<0.35\end{array}\right.;$

W: the conductor layer live width of described strip line.

4. the method for improving the fluctuation of the microwave circuit degree of coupling according to claim 1, is characterized in that, while including the transmission line of two kinds of different live widths in described microwave circuit, described method is specially:

The transmission line of live width maximum is labeled as to object transmission line;

Utilize more than the one group alternative transmission line being connected in parallel to replace described object transmission line, the impedance that more than one group described alternative transmission line is connected in parallel and the impedance phase of described object transmission line with.

5. the method for improving microwave circuit degree of coupling fluctuation according to claim 1, it is characterized in that, when described microwave circuit is two branch directional couplers, while including the transmission line of three kinds of different live widths in described two branch directional couplers, described method is specially:

The transmission line of the live width maximum except impedance matching line is labeled as to object transmission line;

Utilize more than the one group alternative transmission line being connected in parallel to replace described object transmission line, the impedance that more than one group described alternative transmission line is connected in parallel and the impedance phase of described object transmission line with.

6. the method for improving microwave circuit degree of coupling fluctuation according to claim 1, it is characterized in that, when described microwave circuit is three branch directional couplers, while including the transmission line of four kinds of different live widths in described three branch directional couplers, described method is specially:

The transmission line of the live width maximum except impedance matching line is labeled as to object transmission line;

Utilize more than the one group alternative transmission line being connected in parallel to replace described object transmission line, the impedance that more than one group described alternative transmission line is connected in parallel and the impedance phase of described object transmission line with.

7. the method for improving microwave circuit degree of coupling fluctuation according to claim 1, it is characterized in that, when described microwave circuit is decile Wilkinson power divider not, when described not decile Wilkinson power divider includes the transmission line of five kinds of different live widths, described method is specially:

The transmission line of the live width maximum except impedance matching line is labeled as to object transmission line;

Utilize more than the one group alternative transmission line being connected in parallel to replace described object transmission line, the impedance that more than one group described alternative transmission line is connected in parallel and the impedance phase of described object transmission line with.

8. a microwave circuit, described microwave circuit comprises some transmission lines, it is characterized in that, described microwave circuit is prepared according to the method as described in claim 1-7 Arbitrary Term.

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