CN208608341U - Branch line coupler and frequency microwave equipment - Google Patents
Branch line coupler and frequency microwave equipment Download PDFInfo
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- CN208608341U CN208608341U CN201821248015.XU CN201821248015U CN208608341U CN 208608341 U CN208608341 U CN 208608341U CN 201821248015 U CN201821248015 U CN 201821248015U CN 208608341 U CN208608341 U CN 208608341U
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Abstract
The embodiments of the present invention provide a kind of branch line coupler and frequency microwave equipment.According to one embodiment, the branch line coupler includes two first transmission lines being oppositely arranged and two second transmission lines being oppositely arranged.Four transmission lines are sequentially connected end to end in turn composition annular at four points of connection.The length of the length of each first transmission line and each second transmission line is respectively less than a quarter of the operation wavelength of the branch line coupler.The branch line coupler further includes four third transmission lines being respectively arranged at the four points of connection.One end of each third transmission line is connected with a tie point, and each third transmission line is configured to carry out impedance transformation so that the termination impedance at the other end of the third transmission line is system impedance.
Description
Technical field
The embodiments of the present invention relate generally to radio frequency and microwave device, and relate more specifically to branch line coupler
And frequency microwave equipment.
Background technique
The content that this part is introduced is only to facilitate more fully understand the utility model.Therefore, the statement of this part is not
It is interpreted as belonging to which content the prior art or which content is not belonging to the prior art and recognizes.
Branch line coupler (BLC) is the basic device that power distribution and synthesis are used in radio frequency and microwave system.Due to
With simple design and structure, BLC be widely used in power amplifier (such as Doherty (Doherty) power amplifier),
In the equipment such as the feeding network (such as butler matrix (Butler matrix)) of aerial array, frequency mixer.Accordingly, there exist
The demand of the performance of sustained improvement BLC.
Utility model content
There is provided this part is to introduce that further described below in specific embodiment part in simplified form
The selected works of a little concepts.This part is not intended to determine the key features or essential features of theme claimed, also not purport
In the range for limiting theme claimed.
One of the purpose of this utility model is to provide a kind of improved branch line coupler.
One aspect according to the present utility model provides a kind of branch line coupler.The branch line coupler includes phase
To two first transmission lines of setting and two second transmission lines being oppositely arranged.Four transmission lines are first at four points of connection
Tail is sequentially connected composition annular.The length of the length of each first transmission line and each second transmission line is respectively less than the branch line
The a quarter of the operation wavelength of coupler.The branch line coupler further includes being respectively arranged at the four points of connection
Four third transmission lines.One end of each third transmission line is connected with a tie point, and each third transmission line be configured into
Row impedance converts so that the termination impedance at the other end of the third transmission line is system impedance.
According to above-mentioned aspect, due to carrying out impedance transformation using third transmission line, so it is real to be able to use lower impedance
Existing branch line coupler, to reduce insertion loss and improve power capacity.
In the embodiments of the present invention, the length of each third transmission line is less than the work of the branch line coupler
The a quarter of wavelength.
In the embodiments of the present invention, the width of different size in each first transmission line of each third transmission line
With the width of each second transmission line.
In the embodiments of the present invention, each first transmission line, each second transmission line and each third transmission line
It is microstrip line or strip line.
In the embodiments of the present invention, the annular is one of the following: straight-flanked ring, elliptical ring and annulus.
In the embodiments of the present invention, the branch line coupler is set on a printed circuit board or monolithic microwave
In integrated circuit.
In the embodiments of the present invention, the branch line coupler is configured with -1 coupling for arriving -20dB
Degree.
Another aspect according to the present utility model provides a kind of frequency microwave equipment.The frequency microwave equipment includes root
According to the branch line coupler of above-mentioned aspect.
In the embodiments of the present invention, the frequency microwave equipment is one of the following: aerial array, remote radio list
Member, power distribution apparatus and power combining apparatus.
Detailed description of the invention
According to by the detailed description below the illustrative embodiments of the utility model being read in conjunction with the figure, this is practical new
These and other objects, the feature and advantage of type will be apparent.
Fig. 1 is the top view for showing the branch line coupler of embodiment according to the present utility model；
Fig. 2 is the structural schematic diagram for showing Conventional branch line coupler；
Quarter-wave transmission line and its equivalent shortening transmission line is shown respectively in Fig. 3 A and 3B；
Fig. 4 is the structural schematic diagram shown using the branch line coupler for shortening transmission line；
Fig. 5 is the structural schematic diagram of branch line coupler shown in Fig. 1；And
Fig. 6 A to 6C shows the response curve of the emulation of the branch line coupler of embodiment according to the present utility model.
Specific embodiment
For illustrative purposes, some details are explained in the following description in order to provide the saturating of the disclosed embodiments
Thorough understanding.However, it will be apparent to one skilled in the art that be, can without these specific details or
The embodiment is realized using equivalent.
There are some documents about branch line coupler (BLC) at present.For example, the paper of T.Hirota et al.
" Reduced-Size Branch-Line and Rat-Race Hybrids for Uniplanar MMIC ' s " is (see IEEE
Trans.Microw.Theory Tech., 1990,38, (3), 270-275 pages) it proposes a kind of with reduced size
BLC.But the bandwidth of the BLC is narrower than conventional quarter-wave BLC.Moreover, the BLC needs higher impedance, this is usually
It will lead to biggish insertion loss.The width that high impedance also results in microstrip line narrows, and the problem is in desired power-division ratios
Become especially serious in higher situation.This makes BLC be difficult to be manufactured with single layer microstrip line.
The embodiments of the present invention propose a kind of improved BLC.It hereinafter, will be detailed with reference to Fig. 1 to Fig. 6 A-6C
Thin description the embodiments of the present invention.
Fig. 1 is the top view for showing the BLC of embodiment according to the present utility model.As shown, the BLC includes opposite sets
Two first transmission lines 101-1,101-2 set, and two second transmission lines 102-1,102-2 being oppositely arranged.For example, each
First transmission line and each second transmission line can be microstrip line or strip line.The length of first transmission line 101-1,101-2
For L1, and width is W1.The length of second transmission line 102-1,102-2 is L2, and width is W2.Each first transmission line
The length L1 and length L2 of each second transmission line is respectively less than a quarter of the operation wavelength of the BLC.About these length and
The setting of width will be described in detail later referring to Fig. 2 to 5.
Four transmission lines 101-1,101-2,102-1, the 102-2 are in the four points of connection (position in Fig. 1 where A, B, C, D
Set) at be sequentially connected end to end in turn composition annular.Although the annular in Fig. 1 is straight-flanked ring, the utility model is not limited to this and shows
Example.As another example, each first transmission line and each second transmission line can not use straight line but use circular arc line,
Making obtained annular is elliptical ring or annulus.As another example, annular can be constituted using meander line.In addition, can also
According to actual needs, to constitute annular using the line of other arbitrary shapes.
The BLC further includes four third transmission line 103-1 to 103-4 being respectively arranged at four points of connection A, B, C, D.
One end of each third transmission line is connected with a tie point, and each third transmission line is configured to carry out impedance transformation so that should
Termination impedance at the other end of third transmission line is system impedance.The length of third transmission line is L, and width is W.About this
The details of setting and the impedance transformation of length and width, will be described in detail later referring to Fig. 2 to 5.It should be noted that Fig. 1
Middle width is the transmission line that the transmission line of W0 is for the BLC to be connected with external input/output, therefore is not the BLC
Component part.It it should also be noted that each size of BLC shown in Fig. 1 is merely exemplary, and is not restricted
's.
Due to carrying out impedance transformation using third transmission line, so being able to use lower impedance realizes BLC, to drop
Low insertion loss and raising power capacity.The improvement is high power distribution ratio (or weak coupling degree, such as -10dB) the case where
Under be especially apparent because the high impedance in high power distribution ratio situation can narrow due to the width of microstrip line and cause micro- in single layer
It is difficult with the practical manufacture on line.Therefore, the BLC of the embodiment can be applicable in any power-division ratios (for example, corresponding coupling
Degree is -1 to -20dB) and can be easily implemented in printed circuit board (PCB) or monolithic integrated microwave circuit (MMIC).
Next, by the design process for the BLC for describing the embodiments of the present invention referring to figs. 2 to 5.As an explanation
Property example, consider work the -2dB of B1 frequency range (2110-2170MHz) BLC, use single layer microstrip line realize.It should infuse
Meaning, the principles of the present invention also can be applied to other frequency ranges and the degree of coupling.The design process may include five steps
Suddenly.In first step, the structure of routine BLC is designed.Fig. 2 is the structural schematic diagram for showing conventional BLC.As shown, the BLC packet
Including has (feature) impedance Z01Two quarter-wave transmission lines and have impedance Z02Two quarter-wave long passes
Defeated line.Four quarter-wave transmission lines are sequentially connected end to end in turn composition annular.Port 1 is entry port, and port 3 is coupling
Port, port 2 is straight-through port, and port 4 is isolated port.Design formula for routine BLC is as follows:
K in above formula is the power P at coupling port 33With the power P at entry port 11Between ratio, C0It is
The degree of coupling of BLC, Z0rIt is the reference termination impedance of all of the port of BLC.For the coupler of -2dB, C0=-2.It is assumed that Z0r=
30 Ω can then be calculated according to above formula: Z01=18.2 Ω, Z02=22.9 Ω.
In second step, the quarter-wave transmission line in conventional BLC is replaced with to equivalent shortening transmission line, is obtained
Using the BLC for shortening transmission line.Fig. 3 A shows the quarter-wave transmission line that the conventional BLC of Fig. 2 is used.As shown in Figure 3A,
It is assumed that the quarter-wave transmission line has impedance Zc.Fig. 3 B shows the contracting equivalent with the quarter-wave transmission line of Fig. 3 A
Short transmission line.As shown in Figure 3B, it is assumed that the shortening transmission line has impedance Z and electrical length θ.Distinguish at the both ends of the shortening transmission line
Shunt capacitance C to ground.Relationship between transmission line shown in Fig. 3 A and 3B can be indicated with following formula:
As pi/2 < θ < π, it should replace capacitor C using inductance L, i.e.,
ω in above formula is the corresponding angular speed of center operating frequency of BLC.
By the way that the quarter-wave transmission line in Fig. 2 to be replaced with to the shortening transmission line equivalent with it, available Fig. 4
Shown in using shorten transmission line BLC.As shown in figure 4, there is impedance Z in Fig. 201Two quarter-wave transmission lines
It is replaced by with impedance Z1With electrical length θ1Two transmission lines (its both ends distinguish shunt capacitance C1To ground).With impedance Z02
Two quarter-wave transmission lines be replaced by with impedance Z2With electrical length θ2Two transmission lines (its both ends respectively simultaneously
Join capacitor C2To ground).In the illustrated examples, working frequency range 2110-2170MHz, therefore its centre frequency f0=
2.14GHz.It is assumed that the θ in Fig. 41=θ2=π/3 can then be calculated according to above formula: Z1=21 Ω, C1=2.04pF,
Z2=26.5 Ω, C2=1.62pF.Capacitor C in Fig. 4 is capacitor C1With capacitor C2The capacitor that parallel connection obtains, therefore C=C1+C2。
In third step, the impedance matching network of the BLC of the present embodiment is designed.Fig. 5 is the structural representation of BLC shown in Fig. 1
Figure.As shown, having impedance Z1With electrical length θ1Two transmission lines be first transmission line, have impedance Z2With electrical length θ2
Two transmission lines be second transmission line, have impedance ZTWith electrical length θTFour transmission lines be third transmission line.By comparing
Figure 4 and 5 can be seen that by the way that four capacitor C in BLC shown in Fig. 4 are replaced with four third transmission lines, available figure
BLC shown in 5.That is, the third transmission line in Fig. 5 absorbs the reactance in Fig. 4, (such as capacitor C, which may also
It is inductance), play the role of impedance transformer.The load impedance transform of first and second transmission lines is by the impedance transformer
System impedance Z0(usually such as 50 Ω).The load impedance Z to be matched can be indicated are as follows:
Wherein Z0rIt is the reference termination impedance of all of the port of BLC shown in Fig. 2 (it is assumed that 30 in this illustrated examples
Ω), ω is the corresponding angular speed of center operating frequency of the BLC, C=C1+C2.Band can be calculated according to above formula
The impedance Z matched=9.43+j13.93 Ω.
If with having impedance ZTWith electrical length θTSingle transmission line by impedance ZS=RS+jXSIt is matched to impedance ZL=
RL+jXL, then the impedance Z of the transmission lineTWith electrical length θTIt can be indicated with following formula:
In this illustrated examples, need impedance Z=9.43+j13.93 Ω being matched to impedance Z0=50 Ω.Therefore, RS
=9.43 Ω, XS=13.93 Ω, RL=50 Ω, XL=0.It can be calculated according to above formula: ZT=15.25 Ω, θT=
41.6°.In this way, just having obtained the impedance of the third transmission line of BLC shown in fig. 5.It should be noted that impedance matching network is simultaneously
It is not limited to above-mentioned single microstrip line, but Smith chart (Smith Chart) (such as minor matters in various ways can also be passed through
Matching) it realizes.
In four steps, the physical size of the BLC of the present embodiment is calculated to construct its physical structure.The impedance of microstrip line with
Relationship between width W can be expressed as follows:
Z in above formula0It is the characteristic impedance of microstrip line, εeIt is the effective dielectric constant of microstrip line, W ' is and microstrip line
Relevant intermediate parameters, the h such as width W be the thickness of PCB dielectric substrate, εrIt is the relative dielectric constant of PCB substrate, t is micro-
Thickness with line.In this way, can use above formula, its width is calculated from the impedometer of the first, second, and third transmission line.Separately
Outside, the length L of microstrip line can be indicated are as follows:
θ in above formula is the electrical length of microstrip line, and λ is the wavelength of the electromagnetic signal by microstrip line transmission, v and f
The rate and frequency of the electromagnetic signal, μ and ε are the magnetic conductivity and dielectric constant of PCB substrate, c be electromagnetic wave in a vacuum
Spread speed, μrIt is the relative permeability of PCB substrate.
In the illustrated examples, use typical RO4350B medium as PCB substrate.The PCB substrate can be from
Rogers company buys, and with 3.66 relative dielectric constant (εr=3.66) and the thickness (h=of 0.508mm
0.508mm).The thickness t of microstrip line can take 35 μm of representative value.In this way, by by these parameters and second and third step
The impedance of counted each transmission line substitutes into above formula in rapid, can calculate the length and width of each transmission line.It should be noted that
It is that these physical sizes of BLC can also be using the imitative of such as ADS (high-level design system) and AWR (studying using wave) etc
True tool is calculated.
In the 5th step, full-wave electromagnetic emulation and optimization are executed.It is first according to being obtained by above-mentioned first to fourth step
Beginning size can use the physical structure that CAD (CAD) tool constructs BLC.HFSS (high frequency can be used
Structure Simulator) realize emulation and optimization, wherein HFSS is the full-wave electromagnetic solver of Ansoft company exploitation.Following table 1
The final optimization pass size for the BLC that emulation obtains is shown.
| Parameter | W0 | W1 | L1 | W2 | L2 | W | L |
| Unit (mm) | 1.07 | 3.4 | 12.9 | 2.7 | 12.6 | 5.35 | 8.8 |
Table 1 emulates the size of obtained BLC
In addition, also simulating the response curve of the BLC in HFSS.Fig. 6 A shows S11 the and S41 curve that emulation obtains.
Parameter S11 indicates return loss, and parameter S41 indicates isolation.As shown, in the working frequency range 2110-2170MHz emulated
Interior, return loss is at least -24.5dB, and isolation is at least -23dB.The amplitude that Fig. 6 B shows S21 and S31 that emulation obtains is rung
Answer curve.Parameter S21 indicates that positive transmission coefficient, parameter S31 indicate the degree of coupling.As shown, in the working frequency range emulated
In 2110-2170MHz, the degree of coupling changes between -2.2335dB to -2.2679, close to the target degree of coupling -2dB.Fig. 6 C is shown
Emulate the phase response curve of obtained S21 and S31.As shown, in the centre frequency 2.14GHz of the working frequency range emulated
Place, the phase difference led directly between end and the output signal of coupled end are 90 degree.Therefore, the simulation result of Fig. 6 A to 6C is set with theory
Meter coincide good, shows that the BLC of the present embodiment can work and with good performance.
In addition, the utility model additionally provides the frequency microwave equipment of BLC comprising examples described above a kind of.Example
Such as, which can be aerial array, Remote Radio Unit (RRH), power distribution apparatus, power combining apparatus
Deng.Particularly, it is extensive more can be advantageously applied to the 5th third-generation mobile communication technology (5G) by the BLC of examples described above
It inputs and carries out power distribution and synthesis in multi output (massive MIMO) equipment.Since other of these frequency microwave equipment are matched
Setting is well known to those skilled in the art, therefore its details will not be described in great detail herein.
Unless otherwise defined, otherwise all terms (including technical and scientific term) as used herein have it is practical new with this
The normally understood identical meanings of type theme those skilled in the art institute.It is further to be understood that in usually used word
Those terms defined in allusion quotation, which should be interpreted that, has with context and in the related technology their the consistent meaning of meaning,
And it will not be explained in the form of excessively Utopian, unless in addition explicitly defining herein.As used in this, by two or
More parts, which ' attach ' to statement together and should refer to, to be bonded directly together these parts or by one or more middle parts
Part combines.
It should be noted that " illustrative " place of term used herein, especially when it is located at after one group of term,
It is described it is " illustrative " be only exemplary with it is illustrative, and be not construed as monopolistic.The utility model it is each
A aspect can combine implementation individually or with one or more of the other aspect.In addition, embodiment described herein is intended to only
It is for the purpose of illustration, and is not intended to limit the scope of the utility model.
The disclosure include herein clearly or by its it is any generalization in the form of disclosed in any novel feature or feature
Combination.When read in conjunction with the accompanying drawings, in view of foregoing description, the various modifications and adaptation to above-described embodiment of the disclosure are for phase
It can become for technical staff in the field of pass obvious.However, any and all modifications will fall into the non-limiting of the disclosure
In the range of exemplary embodiment.
Claims (9)
1. a kind of branch line coupler, comprising:
Two first transmission lines being oppositely arranged and two second transmission lines being oppositely arranged, four transmission lines are connected at four
It is sequentially connected end to end in turn at point and constitutes annular, the length of the length of each first transmission line and each second transmission line is respectively less than described
The a quarter of the operation wavelength of branch line coupler；
It is characterized in that, the branch line coupler further include:
Four third transmission lines being respectively arranged at the four points of connection, one end of each third transmission line are connect with one
Point is connected, and each third transmission line is configured to carry out impedance transformation the termination impedance so that at the other end of the third transmission line
For system impedance.
2. branch line coupler according to claim 1, which is characterized in that the length of each third transmission line is less than described
The a quarter of the operation wavelength of branch line coupler.
3. branch line coupler according to claim 1, which is characterized in that each third transmission line it is of different size in every
The width of the width of a first transmission line and each second transmission line.
4. branch line coupler according to claim 1, which is characterized in that each first transmission line, each second transmission
Line and each third transmission line are microstrip line or strip line.
5. branch line coupler according to claim 1, which is characterized in that the annular is one of the following:
Straight-flanked ring；
Elliptical ring；And
Annulus.
6. branch line coupler according to claim 1, which is characterized in that the branch line coupler is arranged on printing
On circuit board or in monolithic integrated microwave circuit.
7. branch line coupler according to claim 1, which is characterized in that the branch line coupler is configured as having
There is -1 degree of coupling for arriving -20dB.
8. a kind of frequency microwave equipment, which is characterized in that including branch line coupling according to any one of claim 1 to 7
Clutch.
9. frequency microwave equipment according to claim 8, which is characterized in that the frequency microwave equipment is one of the following:
Aerial array；
Remote Radio Unit；
Power distribution apparatus；And
Power combining apparatus.
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| CN201821248015.XU CN208608341U (en) | 2018-08-03 | 2018-08-03 | Branch line coupler and frequency microwave equipment |
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| CN201821248015.XU CN208608341U (en) | 2018-08-03 | 2018-08-03 | Branch line coupler and frequency microwave equipment |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114497962A (en) * | 2021-12-22 | 2022-05-13 | 中国电子科技集团公司第二十九研究所 | Design method of broadband impedance matching directional coupler |
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2018
- 2018-08-03 CN CN201821248015.XU patent/CN208608341U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114497962A (en) * | 2021-12-22 | 2022-05-13 | 中国电子科技集团公司第二十九研究所 | Design method of broadband impedance matching directional coupler |
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