CN103647131B - A kind of method and microwave circuit that improves the fluctuation of the microwave circuit degree of coupling - Google Patents

Abstract

The invention discloses a kind of method and microwave circuit that improves the fluctuation of the microwave circuit degree of coupling, relate to microwave communication field, the impact that its transmission line of the microwave circuit of preparing according to the method produces the microwave circuit degree of coupling in the time 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. The method of improving the fluctuation of the microwave circuit degree of coupling of the embodiment of the present invention, 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 the trend that affects on 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.

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 of improving the fluctuation of the microwave circuit degree of couplingAnd microwave circuit.

Background technology

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

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

As a rule, transmission line can directly be formed on the substrate of microwave circuit by means of typography, therebyGreatly simplify the preparation process of microwave circuit.

Taking transmission line as microwave line or belt shape line is as example, as shown in Figure 1, Fig. 1 is microwave line or belt shape lineGeneralized section. Wherein its impedance of microwave line or belt shape line is mainly by conductor layer live width w (namely conductor layerThe live width of radiation patch forming), conductor layer is to distance h (or the h with reference to ground₁、h₂) and medium materialThe parameters such as material ε r determine. That is to say, can determine microwave line or belt shape by controlling above-mentioned relevant parameterThe impedance of line.

But inventor finds that in prior art, at least there are the following problems: because typography may be sent outRaw over etching or owe the situation of etching, has therefore just caused the transmission line forming to occur mismachining tolerance. CorrespondingIn Fig. 1, due to the over etching of typography or owe etching, may cause the conductor layer of microwave line or belt shape lineThere is deviation in live width w, and then causes again the variation of microwave line or belt shape line impedence, finally caused microwave electricityRoad degree of coupling performance worsens. And prior art processes cannot be avoided the microwave circuit coupling causing because of mismachining toleranceThe situation of degree 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,Its transmission line of the microwave circuit of preparing according to the method there is over etching or while owing lithography error to microwaveThe impact that coupling of circuits degree produces can be cancelled out each other, thereby reduces mismachining tolerance to the microwave circuit degree of couplingThe impact of energy.

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, calculate the transmission line of described live width minimum in mistakeEtching or owe the trend that affects on the described microwave circuit degree of coupling in etching process;

Calculate in described microwave circuit other transmission line at over etching or in owing etching process to described microwave circuitThe trend that affects of the degree of coupling, is coupled to described microwave circuit at over etching or in owing etching process at least oneThe trend that affects of degree and the transmission line of described live width minimum at over etching or in owing etching process to described microwave electricityThe contrary transmission line of the trend that affects of the road degree of coupling is labeled as object transmission line;

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

In the possible implementation of the first, in the time that described alternative transmission line is microstrip line, described microstrip lineImpedance and conductor layer live width between 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}\[\frac{w}{d}+1.393+0.667ln(\frac{w}{d}+1.444)\]},w/d\≥1\end{array}\right.;$

Z₀: the resistance value of described microstrip line; W: the conductor layer live width of described microstrip line; D: in described microstrip lineConductor layer and with reference to the distance between ground; ε e: the effective dielectric constant of described microstrip line, described microstrip lineEffective dielectric constant meet:

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

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

In the possible implementation of the second, in the time that described alternative transmission line is strip line, described strip lineImpedance and conductor layer live width between meet:

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

Z₀: 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, instituteThe effective width of stating 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, when including the biography of two kinds of different live widths in described microwave circuitWhen defeated line, 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, one group many institutesState substitute the impedance that is connected in parallel of transmission line and described object transmission line impedance phase together.

In the 4th kind of possible implementation, when described microwave circuit is two branch directional couplers, described inWhile including the transmission line of three kinds of different live widths in 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, one group many institutesState substitute the impedance that is connected in parallel of transmission line and described object transmission line impedance phase together.

In the 5th kind of possible implementation, when described microwave circuit is three branch directional couplers, described inWhile including the transmission line of four kinds of different live widths in 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, one group many institutesState substitute the impedance that is connected in parallel of transmission line and described object transmission line impedance phase together.

In the 6th kind of possible implementation, when described microwave circuit divides for decile Wilkinson power notOrchestration, when described not decile Wilkinson power divider includes the transmission line of five kinds of different live widths, instituteThe method of stating 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, one group many institutesState substitute the impedance that is connected in parallel of transmission line and described object transmission line impedance phase together.

On the other hand, the present invention also provides a kind of microwave circuit, and described microwave circuit comprises some biographiesDefeated line, 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 this transmission line microwave circuit is coupledThe trend that affects of degree; To the trend that affect of the microwave circuit degree of coupling be affected to the transmission line that trend is contrary with above-mentionedBe labeled as object transmission line; Utilize more than the one group alternative transmission line being connected in parallel to replace object transmission line and manyIt is consistent with object transmission line impedence that root substitutes transmission line parallel impedance. By above-mentioned steps, can make microwave electricityThe impact that the transmission line on road produces the microwave circuit degree of coupling in the time over etching occurring or owe lithography error canTo cancel out each other, thereby reduce the impact of mismachining tolerance on microwave circuit degree of coupling performance.

Brief description of the drawings

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, below will be to implementingIn example or description of the Prior Art, the accompanying drawing of required use is briefly described, and apparently, the following describesIn accompanying drawing be only some embodiments of the present invention, for those of ordinary skill in the art, do not payingGo out 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 method processing afterwards electricity of two branch directional couplers of generation of Fig. 6 for providing according to the embodiment of the present inventionLine structure schematic diagram;

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 method processing afterwards electricity of three branch directional couplers of generation of Figure 11 for providing according to the embodiment of the present inventionLine structure schematic diagram;

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 not decile Wilkinson power divider;

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 method processing rear not decile Wilkinson power that generates of Figure 16 for providing according to the embodiment of the present inventionThe electrical block diagram of distributor;

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

Detailed description of the invention

Embodiments of the invention provide a kind of method of improving the fluctuation of the microwave circuit degree of coupling, according to the party's legal systemIts transmission line of standby microwave circuit produces the microwave circuit degree of coupling in the time over etching occurring or owe lithography errorRaw impact 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 instead of in order to limit, proposed such as particular system structure, interface,The detail of technology and so on, understands the present invention to thoroughly cut. But those skilled in the art should be clearChu also can realize the present invention in other embodiment that there is no these details. In other situation,Omit the detailed description to well-known device, circuit and method, in order to avoid unnecessary details hinders thisThe description of 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, as shown in Figure 2,The method comprises:

Step S101: determine the transmission line of live width minimum in microwave circuit, the transmission line that calculates live width minimum existsOver etching or owe the trend that affects on the microwave circuit degree of coupling in etching process;

It should be noted that, in the preparation process of microwave circuit, when the live width of its transmission line because of over etching orOwe etching and 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 that standard live width is 4milLine, and the standard live width transmission line that is 48mil; Obviously, this mismachining tolerance biography thinner to live widthDefeated line impact is comparatively violent, 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 for example, instead of further restriction to transmission line. )

That is to say, the transmission line of live width minimum its impedance variations in the time that mismachining tolerance occurs is the most violent, entersAnd 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,First the transmission line of determining the transmission line of live width minimum and calculate this live width minimum is at over etching or owe etching processIn the trend that affects on the microwave circuit degree of coupling.

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

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

It should be noted that, over etching or owe etching occur time, transmission line is because live width mismachining tolerance all canFluctuation to the microwave circuit degree of coupling exerts an influence. Further, after step S101, obtain the biography of live width minimumDefeated line, continues microwave electricity the affecting after trend of the microwave circuit degree of coupling at over etching or in owing etching processIn road, other transmission line calculates, thereby find at over etching or in owing etching process, microwave circuit is coupledThe trend that affects of degree and the transmission line of step S101 live width minimum at over etching or in owing etching process to microwave electricityThe contrary transmission line of the trend that affects of the road degree of coupling. Then, at least one transmission line of above-mentioned condition will be metBe labeled as object transmission line. As the optional embodiment of one, the same line that has of above-mentioned condition will be metMany wide transmission lines are all labeled as object transmission line.

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

On the basis of completing steps S102, mark after object transmission line, utilize and substitute transmission line to orderMark transmission line carries out equivalent substitution.

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

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

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

Wherein, Z₀: the resistance value of microstrip line; W: the conductor layer live width of microstrip line; D: the conductor in microstrip lineLayer and with reference to the distance between ground; ε e: the effective dielectric constant of microstrip line, the effective dielectric constant of microstrip lineMeet:

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

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

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

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

Z₀: the resistance value of strip line; B: strip line is with reference to ground and with reference to the distance between ground; ε r: strip lineThe relative dielectric constant of dielectric substrate; We: the effective width of stripline conductors layer, strip line center conductor layerEffective width meet:

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

W: the conductor layer live width of strip line. Same, in the definite situation of the resistance value of strip line, by upperState 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, do not repeat at this.

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

On the other hand, can know according to step S102, object transmission line and minimum feature transmission line existOver etching or owe etching process occur time, both are contrary on the trend that affects of the microwave circuit degree of coupling; AndIn step S103, substitute transmission line equivalent substitute object transmission line, this equivalent substitute process can't changeBecome the affect trend of corresponding transmission line on the microwave circuit degree of coupling. Therefore substitute transmission line and object transmission line twoAt over etching or in owing etching process, the trend that affects on the microwave circuit degree of coupling is identical to person. Thus canInfer out, when substituting transmission line and minimum feature transmission line at over etching or owing etching process generation to micro-The trend that affects of the wave circuit degree of coupling is contrary.

In sum, after completing steps S103, substitute the transmission line of transmission line and minimum feature at over etchingOr to owe the trend that affects on the microwave circuit degree of coupling in etching process be contrary, and alternative transmission line is with minimumBoth live widths of the transmission line of live width are comparatively approaching again. Therefore,, in the time that mismachining tolerance occurs, substitute transmission line pairThe transmission line that minimum feature can be effectively offset in the impact of the microwave circuit degree of coupling is at over etching or owe etching mistakeImpact on the microwave circuit degree of coupling in journey, thus the microwave circuit coupling causing because of mismachining tolerance also just improvedRight fluctuation situation.

Further, in conjunction with several concrete microwave circuit structures, the detailed above-described embodiment of describing is carriedA kind of method of improving the fluctuation of the microwave circuit degree of coupling of confession.

As a kind of detailed description of the invention of the present invention, taking microwave circuit as two branch directional couplers are as example.The function of two branch directional couplers is that input signal is divided into two-way output according to certain power proportions. AsShown in Fig. 3, Fig. 3 is each arm admittance schematic diagram of two branch directional couplers. According to microwave circuit transmission lineTheory, can obtain two its ideal orientations of branch line directional coupler shown in Fig. 3 and matching condition and meetRelational expression (3-1) (wherein, U₁For input voltage; U₃、U₄For output voltage); Two output ports are correspondingOutput voltage U₃、U₄Ratio meets relational expression (3-2).

H²＝1+G²(3-1)；

U₃/U₄＝2G/(1-G²+H²)(3-2)；

Further, as shown in Figure 4, Fig. 4 has provided a kind of prior art two branch directional coupler circuitStructural representation. 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 1d are output port, the power division of output signalRatio 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 the transmission line that, also includes three kinds of different live widths in this two branch directional coupler (is supposedTransmission line in this two branch directional coupler is microstrip line). For instance, specifically comprise: two conductorsThe wide microstrip line for w12 of layer line 12, two microstrip lines that conductor layer live width is w13 13 and four impedancesDistribution 14.

Suppose that this two branch directional coupler has adopted one side PCB structure, the PCB back side retains complete Copper Foil and doesFor the reference ground of electric bridge; PCB front Copper Foil forms the required figure of electric bridge by etching mode. By this two branchPort one 1a in directional coupler, as input port, connects sky using 11c, 11d port as output portLine 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 public affairsFormula (3-2), can calculate U₄/U₃=2.5. On the other hand, set ginseng in conjunction with formula (3-1) and otherNumber, for example: substrate medium etc., can be calculated the conductor layer live width w12=4mil of microstrip line 12, corresponding resistanceAnti-value Z12=125 Ω; The conductor layer live width w13=48mil of microstrip line 13, corresponding resistance value Z13=46.4Ω。

Suppose in process, because there is deviation in the conductor layer live width of crossing etching or owe etching microstrip line, shouldThe mismachining tolerance of live width is ± 2mil. Can calculate, in the microwave work of 1800MHz～2100MHzIn frequency range, this two branch directional couplers coupling of circuits degree range of tolerable variance is ± 0.75dB, its degree of couplingSimulation result as shown in Figure 5.

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

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. CauseThis, carry out equivalence to two branch directional coupler microstrip lines 13 of prior art and replace. It should be noted that,Those skilled in the art can utilize simulated program to determine which root transmission line in prior art two branch directional couplersFor object transmission line, be not described in detail at this.

As shown in Figure 6, Fig. 6 for two branches that the method for utilizing the embodiment of the present invention and providing generates after processing fixedTo the structural representation of coupler circuit. Wherein, this two branch directional coupler utilizes one group of three microstrip line13' substitutes the microstrip line 13 of prior art two branch directional couplers in the mode being connected in parallel, and all the other transmissionLine is constant.

Can be calculated, the resistance value that microstrip line 13' is corresponding is Z13'=139.2 Ω (one group of three microstrip line 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 the conductor layer live width w13'=2.6mil of microstrip line 13'. Can find, by equivalenceSubstitute, the conductor layer live width w12 of the conductor layer live width w13' of microstrip line 13' and microstrip line 12 becomes comparatively approaching.Now carry out again the impact of calculating processing error on two branch directional coupler coupling of circuits degree.

Same, suppose in process, because of the conductor layer live width appearance of crossing etching or owing etching microstrip lineDeviation, the mismachining tolerance of this live width is ± 2mil. Can calculate, 1800MHz～2100MHz'sWithin the scope of microwave operational frequencies, this two branch directional couplers coupling of circuits degree range of tolerable variance is ± 0.2dB,Its degree of coupling simulation result as shown in Figure 7.

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

As another kind of detailed description of the invention of the present invention, taking microwave circuit as three branch directional couplers are as example.The function of three branch directional couplers is that input signal is divided into two-way output according to certain power proportions. AsShown in Fig. 8, Fig. 8 is each arm admittance schematic diagram of three branch directional couplers. According to microwave circuit transmission lineTheory, can obtain three its ideal orientations of branch line directional coupler shown in Fig. 8 and matching condition and meetRelational expression (4-1) (wherein, U₁For input voltage; U₃、U₄For output voltage); Two output ports are correspondingOutput voltage U₃、U₄Ratio meets relational expression (4-2).

G₂＝2G₁H²/(1+G₁ ²)(4-1)；

U₃/U₄＝[2G₁H²+G₂(1-G₁ ²)]/2(H²-G₁G₂)(4-2)；

Further, as shown in Figure 9, Fig. 9 has provided a kind of prior art three branch directional coupler circuitStructural representation. 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, the power division of output signalRatio 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.

The transmission line that also includes four kinds of different live widths in this three branch directional coupler (supposes that this three branch is fixedTransmission line in coupler is microstrip line). For instance, specifically comprise: a conductor layer live width is w22Microstrip line 22, two microstrip lines that conductor layer live width is w23 23, four conductor layer live widths to be w24 micro-Band line 24 and four impedance matching lines 25.

Than two branch directional couplers, the bandwidth of three branch directional couplers is wider. Suppose this three branchDirectional coupler has adopted one side PCB structure, and the PCB back side retains the reference ground of complete Copper Foil as electric bridge;PCB front Copper Foil forms the required figure of electric bridge by etching mode. By the end in this three branch directional couplerMouth 21a, as input port, connects antenna even load device using 21c, 21d port as output port, alsoCan 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=2^1/2G². On the other hand, for example, in conjunction with other setup parameter: substrate medium etc.,Can be calculated the conductor layer live width w22=43mil of microstrip line 22, corresponding resistance value Z22=50 Ω; Microstrip line23 conductor layer live width w23=6mil, corresponding resistance value Z23=121 Ω; The conductor layer live width of microstrip line 24W24=63.5mil, corresponding resistance value Z24=35.4 Ω.

Suppose in process, because there is deviation in the conductor layer live width of crossing etching or owe etching microstrip line, shouldThe mismachining tolerance of live width is ± 2mil. Can calculate, in the microwave work of 1710MHz～2170MHzIn frequency range, these three branch directional couplers circuit, 2 degree of coupling ranges of tolerable variance are ± 0.55dB, its couplingDegree simulation result as shown in figure 10.

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

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

As shown in figure 11, rear three branches that generate of method processing that Figure 11 provides for utilizing the embodiment of the present inventionThe structural representation of directional coupler circuit. Wherein, this three branch directional coupler utilizes one group of three micro-bandLine 24' substitutes the microstrip line 24 of prior art three branch directional couplers in the mode being connected in parallel, and all the other biographiesDefeated line is constant.

Can be calculated, the resistance value that microstrip line 24' is corresponding is Z24'=106.2 Ω (one group of three microstrip line 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 the conductor layer live width w24'=8.1mil of microstrip line 24'. Can find, by equivalenceSubstitute, the conductor layer live width w23 of the conductor layer live width w24' of microstrip line 24' and microstrip line 23 becomes comparatively approaching.Now carry out again the impact of calculating processing error on three branch directional coupler coupling of circuits degree.

Same, suppose in process, because of the conductor layer live width appearance of crossing etching or owing etching microstrip lineDeviation, the mismachining tolerance of this live width is ± 2mil. Can calculate, 1710MHz～2170MHz'sWithin the scope of microwave operational frequencies, this three branch directional couplers coupling of circuits degree range of tolerable variance is ± 0.04dB,Its degree of coupling simulation result as shown in figure 12.

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

As another kind of detailed description of the invention of the present invention, with microwave circuit for decile Wilkinson power notDistributor is example. The function of decile Wilkinson power divider is not according to certain merit by input signalRate ratio is divided into two-way output. As shown in figure 13, Figure 13 is decile Wilkinson power divider notEach section of characteristic impedance schematic diagram. According to microwave circuit transmission line theory, can obtain the not decile shown in Figure 13Its each section of characteristic impedance of Wilkinson power divider meets respectively relational expression (5-1), and (5-2) (5-3) (5-4).(wherein, P₂、P₃Be respectively two power outputs that port is corresponding; And P₃/P₂＝K²)

Z₀₃＝Z₀[(1+K²)/K³]^1/2(5-1)

Z₀₂＝K²Z₀₃＝Z₀[K(1+K²)]^1/2(5-2)

Z_2b＝Z₀(K)^1/2(5-3)

Z_3b＝Z₀/(K)^1/2(5-4)

Further, as shown in figure 14, Figure 14 has provided not decile Wilkinson merit of a kind of prior artThe structural representation of rate allotter circuit. Wherein, this not decile Wilkinson power divider comprise threeIndividual port 31a, 31b, 31c; Port 31a is input port, and port 31b, 31c are output port,It is right that the power division ratio of output signal is come according to the impedance of decile Wilkinson power divider transmission line notShould determine.

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

Wherein, decile Wilkinson power divider has not adopted one side PCB structure, and the PCB back side has retainedWhole Copper Foil is 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, 31b, 31c are heldMouthful be output port connection antenna even load device, also can be by the work of connector or wireline test output portMake situation.

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

Same, suppose in process, because of the conductor layer live width appearance of crossing etching or owing etching microstrip lineDeviation, the mismachining tolerance of this live width is ± 2mil. Can calculate, 1710MHz～2170MHz'sWithin the scope of microwave operational frequencies, this not decile Wilkinson power divider degree of coupling range of tolerable variance be ±0.5dB, its degree of coupling simulation result as shown in figure 15.

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

Wherein, for the not decile Wilkinson power divider of prior art, getting rid of impedanceAfter distribution, confirmable, the transmission line of minimum feature is microstrip line 33, and object transmission line is micro-Band line 32 (removing the transmission line of the live width maximum outside impedance matching line). Therefore, the not decile to prior artWilkinson power divider microstrip line 32 carries out equivalence and replaces. Same, those skilled in the art can profitWith simulated program determine prior art not in decile Wilkinson power divider any root transmission line be that target passesDefeated line, is not described in detail at this.

As shown in figure 16, the rear not decile generating of method processing that Figure 16 provides for utilizing the embodiment of the present inventionThe structural representation of Wilkinson power divider circuits. Wherein, this decile Wilkinson power division notDevice utilizes one group of two microstrip line 32' to substitute not decile Wilkinson merit of prior art in the mode being connected in parallelThe microstrip line 32 of rate distributor, and all the other transmission lines are constant.

Can be calculated, the resistance value that microstrip line 32' is corresponding is Z32'=94 Ω (one group of two microstrip line 32' parallel connectionResistance value after connection equals the resistance value of microstrip line 32). And further (1-2) can according to formula (1-1)To calculate, the conductor layer live width w33 of the conductor layer live width w32' of microstrip line 32' and microstrip line 33 becomesFor approaching. Now carry out again calculating processing error to the not impact of the decile Wilkinson power divider degree of coupling.

Suppose in process, because there is deviation in the conductor layer live width of crossing etching or owe etching microstrip line, shouldThe mismachining tolerance of live width is ± 2mil. Can calculate, in the microwave work of 1710MHz～2170MHzIn frequency range, this not decile Wilkinson power divider degree of coupling range of tolerable variance be ± 0.25dB, itsDegree of coupling simulation result as shown in figure 17.

So far, can find by Figure 15 and Figure 17, after the method providing by the embodiment of the present invention is processedNot decile Wilkinson power divider, it has obtained because of the degree of coupling fluctuation situation that mismachining tolerance causesImprove.

In sum, those skilled in the art are confirmable: the method for utilizing the embodiment of the present invention to provideAfter microwave circuit is processed, can make the transmission line of microwave circuit over etching occur or owing lithographyImpact when error, the microwave circuit degree of coupling being produced is cancelled out each other, thereby reduces mismachining tolerance to microwave circuitThe impact of degree of coupling performance.

In addition, as another kind of detailed description of the invention of the present invention, when including two kinds in microwave circuitWhen the transmission line of different live widths, 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 biography being connected in parallelDefeated line to be to replace object transmission line, more than one group impedance that alternative transmission line is connected in parallel and object transmission lineImpedance phase is same.

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

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 comprise withLower step: determine the transmission line of live width minimum and calculate the affect trend of this transmission line on the microwave circuit degree of coupling;To the trend that affect of the microwave circuit degree of coupling be affected the transmission line that trend is contrary and is labeled as object transmission with above-mentionedLine; Utilize more than the one group alternative transmission line being connected in parallel to replace object transmission line and many alternative transmission lines alsoConnection impedance is consistent with object transmission line impedence. By above-mentioned steps, can make the transmission line of microwave circuit send outThe impact when giving birth to over etching or owing lithography error, the microwave circuit degree of coupling being produced can be cancelled out each other, fromAnd 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 someTransmission line, this microwave circuit is prepared according to the mentioned method of above-described embodiment. Wherein, about howProcess the microwave circuit that generates the present embodiment, its concrete treatment step can being correlated with reference to said method embodimentDescribe, do not repeat at this. Unique it should be noted that, the microwave electricity of mentioning in above-mentioned detailed description of the inventionLine structure and transmission line kind 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 toThis, any be familiar with those skilled in the art the present invention disclose technical scope in, can expect easilyChange or replace, within all should being encompassed in protection scope of the present invention. Therefore, protection scope of the present invention shouldProtection domain with described claim is as the criterion.

Claims (8)

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

Determine the transmission line of live width minimum in described microwave circuit, calculate the transmission line of described live width minimum in mistakeEtching or owe the trend that affects on the described microwave circuit degree of coupling in etching process;

Calculate in described microwave circuit other transmission line at over etching or in owing etching process to described microwave circuitThe trend that affects of the degree of coupling, is coupled to described microwave circuit at over etching or in owing etching process at least oneThe trend that affects of degree and the transmission line of described live width minimum at over etching or in owing etching process to described microwave electricityThe contrary transmission line of the trend that affects of the road degree of coupling is labeled as object transmission line;

Utilize one group of alternative transmission line being connected in parallel to replace described object transmission line, described in one group, substitute transmissionThe impedance phase of impedance and described object transmission line that line parallel connects together, described alternative transmission line be microstrip line orStrip line.

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

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

Z₀: the resistance value of described microstrip line; W: the conductor layer live width of described microstrip line; D: in described microstrip lineConductor layer and with reference to the distance between ground; ε e: the effective dielectric constant of described microstrip line, described microstrip lineEffective dielectric constant meet:

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

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,In the time that described alternative transmission line is strip line, between the impedance of described strip line and conductor layer live width, meet:

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

Z₀: 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, instituteThe effective width of stating strip line center conductor layer meets:

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

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,In the time 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 one group of alternative transmission line being connected in parallel to replace described object transmission line, described in one group, substitute and passThe impedance that defeated line parallel connects and the impedance phase of described object transmission line are same.

5. the method for improving the fluctuation of the microwave circuit degree of coupling according to claim 1, is characterized in that,When described microwave circuit is two branch directional couplers, in described two branch directional couplers, include three kinds notDuring with the transmission line of live width, described method is specially:

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

Utilize one group of alternative transmission line being connected in parallel to replace described object transmission line, described in one group, substitute and passThe impedance that defeated line parallel connects and the impedance phase of described object transmission line are same.

6. the method for improving the fluctuation of the microwave circuit degree of coupling according to claim 1, is characterized in that,When described microwave circuit is three branch directional couplers, in described three branch directional couplers, include four kinds notDuring with the transmission line of live width, described method is specially:

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

Utilize one group of alternative transmission line being connected in parallel to replace described object transmission line, described in one group, substitute and passThe impedance that defeated line parallel connects and the impedance phase of described object transmission line are same.

7. the method for improving the fluctuation of the microwave circuit degree of coupling according to claim 1, is characterized in that,When described microwave circuit is decile Wilkinson power divider not, described not decile Wilkinson powerWhen distributor 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 one group of alternative transmission line being connected in parallel to replace described object transmission line, described in one group, substitute and passThe impedance that defeated line parallel connects and the impedance phase of described object transmission line are same.

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