CN105186089A - Miniaturized high-frequency ratio microwave dual-frequency power divider - Google Patents

Abstract

The invention discloses a miniaturized high-frequency ratio microwave dual-frequency power divider, and belongs to the field of multi-frequency power dividers. The miniaturized high-frequency ratio microwave dual-frequency power divider comprises an isolating resistor and two dual-frequency impedance transformers, wherein each dual-frequency impedance transformer comprises a symmetrical three-section stepped impedance transmission line; and the two dual-frequency impedance transformers are connected with each other in a parallel form and the isolating resistor is loaded, so as to achieve the dual-frequency power divider. The miniaturized high-frequency ratio microwave dual-frequency power divider is simple in circuit design, adjustable and controllable in work frequency, relatively high in ratio of two frequencies, relatively small in overall size and relatively low in cost, and can be achieved by planar transmission lines of a microstrip line, a strip line and the like.

Description

A kind of miniaturized large frequency ratio microwave dual-frequency power divider

Technical field

The present invention relates to a kind of miniaturized large frequency ratio microwave dual-frequency power divider, it belongs to multifrequency power splitter field.

Background technology

At present, the implementation of microwave dual-frequency power divider generally has following several:

1. design dual-frequency power divider based on the transmission line loading reactance or resistive element.The design loading reactance can make circuit structure complicated, and brings ghost effect.For the scheme of loading resistor element, although circuit is relatively simple, the work frequency ratio that can realize is relatively little.

2. based on the dual-frequency power divider that coupled structure designs.This kind of design lays particular emphasis on replaces traditional quarter-wave transmission line by coupled structure or uses coupled structure to realize dual-frequency power divider at output port.Although based on the power divider circuit compact conformation of this kind of scheme, relevant theory deduction more complicated, is not easy to widely apply.

3. design power splitter based on double frequency impedance transformer network.Because double frequency impedance transformer network has different implementation structures as Τ type or Π type or Γ type or E type structure and modified node method thereof, designer can according to miniaturization, work frequency ratio scope, the design objects such as merit point bandwidth select suitable implementation structure, therefore, this kind of scheme has good flexibility.

Summary of the invention

Goal of the invention: in order to overcome the deficiencies in the prior art, the invention provides a kind of miniaturized microwave dual-frequency power divider, with the work solving dual-frequency power divider frequently smaller, the problem such as implementation structure size is comparatively large, bandwidth is narrower, this dual-frequency power divider can use microstrip line, the planar transmission line forms such as strip line realize, and cost is lower.

Technical scheme: for achieving the above object, the technical solution used in the present invention is:

A kind of miniaturized large frequency ratio microwave dual-frequency power divider, comprise an isolation resistance and two double frequency impedance transformers, wherein, double frequency impedance transformer is made up of symmetric form three-section type stepped impedance transmission line, by being connected with parallel form by two double frequency impedance transformers and loading isolation resistance thus realize dual-frequency power divider.

Preferred: the two frequency bins of described double frequency impedance transformer all can be equivalent to K converter.

Preferred: the structural parameters of K transformer configuration in described double frequency impedance transformer:

$\left\{\begin{array}{c}\frac{1}{{\tan }^2{\mathrm{\θ}}_1}-1=r+1/r\\ \frac{1}{{\tan }^2\left({\mathrm{m\θ}}_1\right)}-1=r+1/r\\ {\mathrm{sin\θ}}_1(2{\cos }^2{\mathrm{\θ}}_1+(1/r){\cos }^2{\mathrm{\θ}}_1-r{\sin }^2{\mathrm{\θ}}_1)=\±Z_T/Z_1\\ sin\left({\mathrm{m\θ}}_1\right)\left(2{\cos }^2\right({\mathrm{m\θ}}_1)+(1/r\left){\cos }^2\right({\mathrm{m\θ}}_1)-r{\sin }^2({\mathrm{m\θ}}_1\left)\right)=\±Z_T/Z_1\end{array}\right.;$

Wherein, θ ₁for the electrical length of impedance transmission lines, r is transmission line characteristic impedance ratio, Z _tthe resistance value of K converter, Z ₁for the characteristic impedance of impedance transmission lines.

Preferred: transmission line is in frequency f ₁the electrical length θ at place _f1value be:

$\left\{\begin{array}{c}{\mathrm{\θ}}_{f1}(m\±1)=n\mathrm{\π},(n=1,2,3...)\\ m>6n\±1\end{array}\right.;$

Wherein, θ _f2/ θ _f1=f ₂/ f ₁=m, θ _f1, θ _f2that transmission line is in frequency f respectively ₁, f ₂the electrical length at place.

Preferred: in described double frequency impedance transformer, the structural parameters value of K transformer configuration is:

$\left\{\begin{array}{c}n=1\\ {\mathrm{\θ}}_{f1}=\frac{\mathrm{\π}}{m+1}\\ m>5\end{array}\right.;$

Wherein, a certain integer of n, m is frequency ratio, θ _f1for transmission line is in frequency f ₁the electrical length at place.

Preferred: the physical dimension of described double frequency impedance transformer and frequency ratio relation:

${\stackrel{\‾}{\mathrm{\θ}}}_T=(2{\mathrm{\θ}}_1+{\mathrm{\θ}}_2)/(\mathrm{\π}/2)=\frac{6}{1+m},m>5;$

Wherein, for the normalization electrical length that transmission line is total, θ ₁, θ ₂for the electrical length of impedance transmission lines, θ _f2/ θ _f1=f ₂/ f ₁=m, θ _f1, θ _f2that transmission line is in frequency f respectively ₁, f ₂the electrical length at place.

Preferred: the frequency ratio between described double frequency impedance transformer is 5.2, characteristic impedance 90.4 Ω of the transmission line of one of them, corresponding electrical length 29.0deg@1.0GHz; Characteristic impedance 55.3 Ω of another transmission line, corresponding electrical length 29.0deg@1.0GHz; Characteristic impedance 50 Ω of the port of export.

Preferred: the frequency ratio between described double frequency impedance transformer is 6.0, characteristic impedance 112 Ω of the transmission line of one of them, corresponding electrical length 25.7deg@1.0GHz; Characteristic impedance 41 Ω of another transmission line, corresponding electrical length 25.7deg@1.0GHz; Characteristic impedance 50 Ω of the port of export.

A kind of miniaturized large frequency ratio microwave dual-frequency power divider provided by the invention, compared to existing technology, has following beneficial effect:

(1). because double frequency impedance transformer is made up of symmetric form three-section type stepped impedance transmission line, by two double frequency impedance transformers being connected with parallel form and loading isolation resistance thus realize dual-frequency power divider, therefore the present invention can realize dual-frequency power divider, and its operating frequency is comparatively larger than f2/f1, reaches more than 5; Thus the work solving dual-frequency power divider is smaller, the problem such as implementation structure size is comparatively large, bandwidth is narrower frequently, and the planar transmission line forms such as this dual-frequency power divider can use microstrip line, strip line realize, and cost is lower.

(2). the overall dimensions of power splitter is less, is conducive to the Integrated design of circuit;

(3). the matching at two frequency places is good, and the isolation between output port is high.

Accompanying drawing explanation

The K transformer configuration figure of Fig. 1 wilkinson power splitter;

The structure chart of Fig. 2 notch cuttype double frequency K converter;

The implementation structure figure of Fig. 3 dual-frequency power divider;

The curve chart of the total electrical length of Fig. 4 double frequency K converter normalization;

The impedance plot of the attainable hierarchic structure of Fig. 5;

The insertion loss (S21, S31) of Fig. 6 dual-frequency power divider (frequency ratio is 5.2) and return loss (S11) curve chart of port one;

Return loss (S22) curve chart of the port 2 of Fig. 7 dual-frequency power divider (frequency ratio is 5.2);

Isolation (S32) curve chart of Fig. 8 dual-frequency power divider (frequency ratio is 5.2);

The insertion loss (S21, S31) of Fig. 9 dual-frequency power divider (frequency ratio is 6.0) and return loss (S11) curve chart of port one;

Return loss (S22) curve chart of the port 2 of Figure 10 dual-frequency power divider (frequency ratio is 6.0);

Isolation (S32) curve chart of Figure 11 dual-frequency power divider (frequency ratio is 6.0).

Embodiment

Below in conjunction with accompanying drawing, the present invention is further described.

A K transformer configuration for wilkinson power splitter, as shown in Figure 1.Make the input impedance at input port place and input transmission line realize impedance matching by the impedance transformation function of K converter, thus subtract low power reflection loss.

Its abcd matrix is:

$A=\left(\begin{array}{cc}0& \±{\mathrm{jZ}}_T\\ \±\frac{1}{{\mathrm{jZ}}_T}& 0\end{array}\right)---\left(1\right)$

Wherein, Z _tbe the resistance value of K converter, j is imaginary unit, and A is the transmission matrix of K converter.

Fig. 2 is the structure chart of double frequency K converter.Double frequency impedance transformer is made up of symmetric form three-section type stepped impedance transmission line, and it all can be equivalent to K converter at two Frequency point places, and the equivalent relation namely by Fig. 2 structure and original K converter is analyzed.

The abcd matrix of Fig. 2 structure is:

$A_1=\left[\begin{array}{cc}{\mathrm{cos\θ}}_1& j{\mathrm{sin\θ}}_1{Z}_1\\ j{\mathrm{sin\θ}}_1/Z_1& {\mathrm{cos\θ}}_1\end{array}\right]\left[\begin{array}{cc}{\mathrm{cos\θ}}_2& j{\mathrm{sin\θ}}_2{Z}_2\\ j{\mathrm{sin\θ}}_2/Z_2& {\mathrm{cos\θ}}_2\end{array}\right]\left[\begin{array}{cc}{\mathrm{cos\θ}}_1& j{\mathrm{sin\θ}}_1{Z}_1\\ j{\mathrm{sin\θ}}_1/Z_1& {\mathrm{cos\θ}}_1\end{array}\right]---\left(2\right)$

Wherein, Z ₁, θ ₁characteristic impedance and the electrical length of the impedance transmission lines at two ends, Z ₂, θ ₂be characteristic impedance and the electrical length of middle impedance transmission lines, j is imaginary unit, A ₁for the transmission matrix of Fig. 2 structure.

Result after abbreviation is:

$\left\{\begin{array}{c}{A}_1=D_1={\cos }^2{\mathrm{\θ}}_1{\mathrm{cos\θ}}_2-(\frac{Z_2}{Z_1}+\frac{Z_1}{Z_2}){\mathrm{sin\θ}}_2{\mathrm{sin\θ}}_1{\mathrm{cos\θ}}_1-{\sin }^2{\mathrm{\θ}}_1{\mathrm{cos\θ}}_2\\ B_1=j2Z_1{\mathrm{cos\θ}}_2{\mathrm{sin\θ}}_1{\mathrm{cos\θ}}_1+j{\mathrm{sin\θ}}_2(Z_2{\cos }^2{\mathrm{\θ}}_1-\frac{Z_1^2}{Z_2}{\sin }^2{\mathrm{\θ}}_1)\\ C_1=j2{\mathrm{cos\θ}}_2{\mathrm{sin\θ}}_1{\mathrm{cos\θ}}_1/Z_1+j{\mathrm{sin\θ}}_2({\cos }^2{\mathrm{\θ}}_1/Z_2-\frac{Z_2}{Z_1^2}{\sin }^2{\mathrm{\θ}}_1)\end{array}\right.---\left(3\right)$

Wherein, A ₁, B ₁, C ₁, D ₁for the matrix element of transmission matrix.

Following formula is obtained by two matrix parameter are equal:

$\left\{\begin{array}{c}\frac{1-{\tan }^2{\mathrm{\θ}}_1}{{\mathrm{tan\θ}}_2{\mathrm{tan\θ}}_1}=(\frac{Z_2}{Z_1}+\frac{Z_1}{Z_2})\\ sin2{\mathrm{\θ}}_1{\mathrm{cos\θ}}_2+{\mathrm{sin\θ}}_2(\frac{Z_2}{Z_1}{\cos }^2{\mathrm{\θ}}_1-\frac{Z_1}{Z_2}{\sin }^2{\mathrm{\θ}}_1)=\±Z_T/Z_1\end{array}\right.---\left(4\right)$

θ can be made to simplify the analysis ₁=θ ₂then have:

$\frac{1-{\tan }^2{\mathrm{\θ}}_1}{{\mathrm{tan\θ}}_2{\mathrm{tan\θ}}_1}=(\frac{Z_2}{Z_1}+\frac{Z_1}{Z_2})\⇒\frac{1}{{\tan }^2{\mathrm{\θ}}_1}-1=r+1/r,({\mathrm{\θ}}_1={\mathrm{\θ}}_2)---\left(5\right)$

Because (4) formula is at two Frequency point place f ₁, f ₂=mf ₁all set up, then have:

$\left\{\begin{array}{c}\frac{1}{{\tan }^2{\mathrm{\θ}}_{f1}}-1=r+1/r\\ \frac{1}{{\tan }^2\left({\mathrm{\θ}}_{f2}\right)}-1=r+1/r\\ {\mathrm{sin\θ}}_{f1}(2{\cos }^2{\mathrm{\θ}}_{f1}+(1/r){\cos }^2{\mathrm{\θ}}_{f1}-r{\sin }^2{\mathrm{\θ}}_{f1})=\±Z_T/Z_1\\ sin\left({\mathrm{\θ}}_{f2}\right)\left(2{\cos }^2\right({\mathrm{\θ}}_{f2})+(1/r\left){\cos }^2\right({\mathrm{\θ}}_{f2})-r{\sin }^2({\mathrm{\θ}}_{f2}\left)\right)=\±Z_T/Z_1\end{array}\right.---\left(6\right)$

Wherein, θ _f1, θ _f2that transmission line is in frequency f respectively ₁, f ₂the electrical length at place, r is transmission line characteristic impedance ratio, and θ _f2/ θ _f1=f ₂/ f ₁=m

θ can be obtained by analyzing (6) formula _f1value condition:

$\left\{\begin{array}{c}{\mathrm{\&theta;}}_{f1}(m\&PlusMinus;1)=n\mathrm{\&pi;},(n=1,2,3...)\\ \frac{1}{{\tan }^2{\mathrm{\&theta;}}_{f1}}-1=r+1/r>2(r>0)\&DoubleRightArrow;0<{\mathrm{\&theta;}}_{f1}<\mathrm{\&pi;}/6\&DoubleRightArrow;m>6n\&PlusMinus;1\end{array}\right.---\left(7\right)$

Wherein, a certain integer of n, m is frequency ratio, θ _f1for transmission line is in frequency f ₁the electrical length at place.

Consider design size miniaturization issues, by (7) formula, each parameter value is:

$\left\{\begin{array}{c}n=1\\ {\mathrm{\&theta;}}_{f1}=\frac{\mathrm{\&pi;}}{m+1}\\ m>5\end{array}\right.---\left(8\right)$

Due to physical dimension and the frequency ratio relation of notch cuttype double frequency K converter, can be weighed by the total normalization electrical length of the K transformer configuration of a certain branch road of power splitter and frequency ratio relation.

${\stackrel{\&OverBar;}{\mathrm{\&theta;}}}_T=(2{\mathrm{\&theta;}}_1+{\mathrm{\&theta;}}_2)/(\mathrm{\&pi;}/2)=\frac{6}{1+m},m>5---\left(9\right)$

Its variation relation curve as shown in Figure 4, therefrom can observe the small size advantage of power splitter.

And the attainable resistance value Z of K transformer configuration in power splitter ₁, Z ₂can be obtained by (6) formula with frequency ratio relational expression, its variation relation curve as shown in Figure 5.

Two operating frequencies are respectively to the dual-frequency power divider of 1GHz and 5.2GHz (frequency ratio is 5.2), structure as shown in Figure 3, (P ₁, P ₂, P ₃, P ₄) be port, by solving (6) formula, can obtain the structural parameters of K converter, being then optimized overall structure with ADS software, characteristic impedance and the electrical length parameter of each transmission line of acquisition are as shown in the table:

z 0(Ω)	50	z r(Ω)	100
				z 1(Ω)	90.4	θ 1(deg@1.0GHz)	29.0
z 2(Ω)	55.3	θ 2(deg@1.0GH x)	29.0

Wherein, z ₀, z _rport diagnostic impedance and isolation resistance respectively.

As Figure 6-Figure 8, characterize coverage diagram S11 and S22 of its emulation, transfer curve S21 and S31, isolation curve S 32.The corresponding S parameter of two frequency bins is:

f ₁＝1.0GHz,|S ₁₁|＝-46.0dB,|S ₂₁|＝-3.0dB,|S ₂₂|＝-85.8dB,|S ₃₂|＝-52.0dB

f ₂＝5.2GHz,|S ₁₁|＝-46.0dB,|S ₂₁|＝-3.0dB,|S ₂₂|＝-64.5dB,|S ₃₂|＝-48.1dB

Bandwidth when isolation is 20dB is respectively:

817.8MHz-1.162GHz,5.051GHz-5.384GHz

Structure to be as shown in Figure 3 respectively 1GHz and 6.0GHz (frequency ratio is 6.0) for two operating frequencies, by solving (6) formula, the structural parameters of K converter can be obtained, then be optimized overall structure with ADS software, characteristic impedance and the electrical length parameter of each transmission line of acquisition are as shown in the table:

z 0(Ω)	50	z r(Ω)	100
				z 1(Ω)	122	θ 1(deg@1.0GHz)	25.7
z 2(Ω)	41	θ 2(deg@1.0GHz)	25.7

Wherein, z ₀, z _rport diagnostic impedance and isolation resistance respectively.

As Figure 9-Figure 11, characterize coverage diagram S11 and S22 of its emulation, transfer curve S21 and S31, isolation curve S 32.The corresponding S parameter of two frequency bins is:

f ₁＝1.0GHz,|S ₁₁|＝-68.4dB,|S ₂₁|＝-3.0dB,|S ₂₂|＝-75.5dB,|S ₃₂|＝-72.3dB

f ₂＝6.0GHz,|S ₁₁|＝48.3dB,|S ₂₁|＝-3.0dB,|S ₂₂|＝-58.3dB,|S ₃₂|＝-50.0dB

Bandwidth when isolation is 20dB is respectively:

850.1MHz-1.162GHz,5.837GHz-6.160GHz

This double frequency 3dB power splitter can use the planar transmission line such as microstrip line, strip line form to realize, and cost compare is low.The present invention adopts symmetric form three-section type stepped impedance transmission line to form double frequency impedance transformer, and real data shows, the overall electrical length of this double frequency impedance transformer is less than 90 degree at first job frequency place, and size is relatively little.Owing to not loading the resonant elements such as any minor matters line, so the bandwidth of operation of dual-frequency power divider reality is relatively wide.

The above is only the preferred embodiment of the present invention, it should be pointed out that for those skilled in the art, can also make some improvement under the premise without departing from the principles of the invention, and these improvement also should be considered as protection scope of the present invention.

Claims (8)

1. a miniaturization large frequency ratio microwave dual-frequency power divider, it is characterized in that: comprise an isolation resistance and two double frequency impedance transformers, wherein, double frequency impedance transformer is made up of symmetric form three-section type stepped impedance transmission line, by being connected with parallel form by two double frequency impedance transformers and loading isolation resistance thus realize dual-frequency power divider.

2. miniaturization according to claim 1 large frequency ratio microwave dual-frequency power divider, is characterized in that: the two frequency bins of described double frequency impedance transformer all can be equivalent to K converter.

3. miniaturization according to claim 2 large frequency ratio microwave dual-frequency power divider, is characterized in that: the structural parameters of K transformer configuration in described double frequency impedance transformer:

$\left\{\begin{array}{c}\frac{1}{{\tan }^2{\mathrm{\&theta;}}_1}-1=r+1/r\\ \frac{1}{{\tan }^2\left({\mathrm{m\&theta;}}_1\right)}-1=r+1/r\\ {\mathrm{sin\&theta;}}_1(2{\cos }^2{\mathrm{\&theta;}}_1+(1/r){\cos }^2{\mathrm{\&theta;}}_1-r{\sin }^2{\mathrm{\&theta;}}_1)=\&PlusMinus;Z_T/Z_1\\ \sin \left({\mathrm{m\&theta;}}_1\right)\left(2{\cos }^2\right({\mathrm{m\&theta;}}_1)+(1/r\left){\cos }^2\right({\mathrm{m\&theta;}}_1)-r{\sin }^2({\mathrm{m\&theta;}}_1\left)\right)=\&PlusMinus;Z_T/Z_1\end{array}\right.;$

Wherein, θ ₁for the electrical length of impedance transmission lines, r is transmission line characteristic impedance ratio, Z _tthe resistance value of K converter, Z ₁for the characteristic impedance of impedance transmission lines.

4. miniaturization according to claim 4 large frequency ratio microwave dual-frequency power divider, is characterized in that: transmission line is in frequency f ₁the electrical length θ at place _f1value be:

$\left\{\begin{array}{c}{\mathrm{\&theta;}}_{f1}(m\&PlusMinus;1)=n\mathrm{\&pi;},(n=1,2,3...)\\ m>6n\&PlusMinus;1\end{array}\right.;$

Wherein, θ _f2/ θ _f1=f ₂/ f ₁=m, θ _f1, θ _f2that transmission line is in frequency f respectively ₁, f ₂the electrical length at place.

5. miniaturization according to claim 5 large frequency ratio microwave dual-frequency power divider, is characterized in that: in described double frequency impedance transformer, the structural parameters value of K transformer configuration is:

$\left\{\begin{array}{c}{\mathrm{\&theta;}}_{f1}=\frac{\mathrm{\&pi;}}{m+1}\\ m>5\end{array}\right.;$

Wherein, m is operating frequency ratio, θ _f1for transmission line is in frequency f ₁the electrical length at place.

6. miniaturization according to claim 1 large frequency ratio microwave dual-frequency power divider, is characterized in that: the physical dimension of described double frequency impedance transformer and frequency ratio relation:

${\stackrel{\&OverBar;}{\mathrm{\&theta;}}}_T=(2{\mathrm{\&theta;}}_1+{\mathrm{\&theta;}}_2)/(\mathrm{\&pi;}/2)=\frac{6}{1+m},m>5;$

Wherein, for the normalization electrical length that transmission line is total, θ ₁, θ ₂for the electrical length of impedance transmission lines, θ _f2/ θ _f1=f ₂/ f ₁=m, θ _f1, θ _f2that transmission line is in frequency f respectively ₁, f ₂the electrical length at place.

7. miniaturization according to claim 1 large frequency ratio microwave dual-frequency power divider, is characterized in that: the frequency ratio between described double frequency impedance transformer is 5.2, characteristic impedance 90.4 Ω of the transmission line of one of them, corresponding electrical length 29.0deg@1.0GHz; Characteristic impedance 55.3 Ω of another transmission line, corresponding electrical length 29.0deg@1.0GHz; Characteristic impedance 50 Ω of the port of export.

8. miniaturization according to claim 1 large frequency ratio microwave dual-frequency power divider, is characterized in that: the frequency ratio between described double frequency impedance transformer is 6.0, characteristic impedance 112 Ω of the transmission line of one of them, corresponding electrical length 25.7deg@1.0GHz; Characteristic impedance 41 Ω of another transmission line, corresponding electrical length 25.7deg@1.0GHz; Characteristic impedance 50 Ω of the port of export.