CN104779431A - Dispersive microwave group delay line - Google Patents

Abstract

A dispersive microwave group delay line comprises a basic unit for tuning the delay time of signal transmission group from a signal source terminal (1) to an output load terminal (5), in which two pairs of unequal length residual sections ((L)_1b,L_1b),(L_2b,L_2b) Two pairs of complementary slot lines ((L) on both sides of the signal layer of the main transmission path (2)_1t,L_1t),(L_2t,L_2t) Arranged on both sides of the ground plane of the microstrip line structure of the main transmission path (2); in the strip line structure body, the unequal length stub is arranged on the middle layer, and the complementary slot line is arranged on the outer conductor of the ground plane of the strip line structure body. The transmission path member having an associated characteristic impedance (Z)_o,2Z_1b,2Z_2b,2Z_1t,2Z_2t) For selecting as control group delay time and reducing the reflected signal from the signal source (1) to the output (5). The cascade connection may form a group delay time system.

Description

Dispersion type micro-wave group delay line

Technical field

The present invention is about a kind of microwave group delay line technology being applied to electromagnetic riveting machine signal.

Background technology

Group delay relates to the theme of electromagnetic communication always, transmission channel must have flat group delay (flat group delay) at passband (pass-band), such as, with the band pass filter (band-pass filter) designed by traditional Chebyshev (Chebyshev) theorem, Butterworth (Butterworth) or oval method, it contains smooth delay at passband, but has larger group delay close to passband edge.In a word, under most of situation, there is no special significance in being with the larger group delay of logical external reaction can say.Therefore, most research concentrates on the smooth delay group of microwave component.But, electromagnetic communication channel in an atmosphere or other transmission channels can bear the change of strong group delay, listed in by pulse signal when considering, time domain beamformer (timedomain waveform) can become distortion distortion, and group delay line then can be used to overcome distortion distortion phenomenon.

Use the look of traditional all-pass formula (all-pass) technology to penetrate delay line and can obtain the less group delay time, the cascade of all-pass formula delay cell connects (cascade connection) and then makes moderate progress obtaining in the reaction compared with jumpbogroup group delaing time, but can increase circuit area and transmission loss.Although surface acoustic wave (surfaceacoustic) device has miniaturization and can provide larger delay, be usually only limitted to be applied in low frequency and narrower frequency range product.Therefore, development has larger frequency selectivity (frequency-sensitive) time of delay and low reaction loss and the group delay line technology that can be used in high frequency has its necessity.

Summary of the invention

The object of the present invention is to provide a kind of dispersion type micro-wave group delay line, it has larger frequency selectivity time of delay and low reaction loses and can be used in high frequency.

A kind of dispersion type micro-wave group delay line of the present invention, at least comprise one by the elementary cell of a signal source to the output load end tuning signal transmission group delay time, described elementary cell comprises a main transmission path for input and output signal, two pairs of non-isometric open circuit stubs are positioned to form induction passband in the middle of main transmission path, and two are positioned at the ground plane of microstrip line construction to the non-isometric complementary line of rabbet joint.

Wherein, each open circuit stub of described elementary cell and the complementary line of rabbet joint are even, non-homogeneous and bending any one form wherein along transmission line.

Wherein, each open circuit stub of described elementary cell is set to multiple field and each complementary line of rabbet joint is set to multiple field.

Wherein, described elementary cell parallel connection open circuit stub characteristic impedance Z _1b, Z _2belectrical length θ ₁, θ ₂, wherein θ ₁≠ θ ₂following formula is met: Z in working band _1bcot θ ₁+ Z _2bcot θ ₂=0.

Wherein, the main transmission path of described elementary cell (2) and open circuit stub ((L _1b, L _1b), (L _2b, L _2b)) be the printed circuit cable of a printed circuit board (PCB) signal layer, the complementary line of rabbet joint ((L _1t, L _1t), (L _2t, L _2t)) for removing the line of rabbet joint region of conductor at ground plane.

Wherein, described elementary cell is with component Z ₁, Z ₂... .., Z _n, wherein n is positive integer, and cascade connects and composes group's delay linear system.

Another dispersion type micro-wave group delay line of the present invention, comprise an elementary cell, described elementary cell is made up of the complementary line of rabbet joint most open-circuit stub and majority, wherein, open circuit stub ((L _1b, L _1b) ... .., (L _nb, L _nb)), the wherein printed circuit cable of n to be positive integer be a printed circuit board (PCB) signal layer, the complementary line of rabbet joint ((L _1t, L _1t) ... .., (L _nt, L _nt)) for removing the line of rabbet joint region of conductor at ground plane.

Another dispersion type micro-wave group delay line of the present invention, at least comprise one by the elementary cell of a signal source (1) to output load end (5) the tuning signal transmission group delay time, described elementary cell comprises a main transmission path (2) for input and output signal, and two to non-isometric open circuit stub ((L _1b, L _1b), (L _2b, L _2b)) be positioned to form induction passband in the middle of main transmission path, two to the non-isometric complementary line of rabbet joint ((L _1t, L _1t), (L _2t, L _2t)) be arranged in bar line structure any layer of upper and lower two-layer ground plane.

Beneficial effect of the present invention is, the dispersion type micro-wave group delay line provided, have larger frequency selectivity time of delay and low reaction loss and can high frequency be used in.

Accompanying drawing explanation

Fig. 1: display represents the equivalent transmission line schematic diagram of group's delay line elementary cell.

Fig. 2: display one is positioned at the non-isometric degree stub elementary cell schematic diagram of top signal layer.

Fig. 3: display one is positioned at the non-isometric degree complementary line of rabbet joint elementary cell schematic diagram of Bottom ground layer.

Fig. 4: show group's delay line elementary cell stereogram.

Fig. 5: show group delay wire system of the present invention and connect via the cascade of elementary cell.

Embodiment

The present invention provide a kind of in order to tuning specific signal frequencies by the group delay networking of a signal source to load output, group delay device comprises a main transmission path and is connected to signal source and output at two ends, two couple of elementary cell non-isometric, in parallel open circuit stub group (L _1b, L _1b), (L _2b, L _2b), and two to complementary line of rabbet joint group non-isometric, in parallel, non-isometric stub line group in parallel directly links main transmission path 2.Wherein, the electrical length θ of a pair non-isometric stub _i(i=1,2) are different from another to stub (L _2b, L _2b).In other words, electrical (and physics) length of two stub groups is different from each other as shown in Figure 1, and θ ₁≠ θ ₂.Stub group (2Z _1b, 2Z _1b) and stub group (2Z _2b, 2Z _2b) electrical length different.The complementary line of rabbet joint of two couples of two pairs of non-isometric open circuit stubs is omitted at Fig. 1.Two pairs of non-isometric stubs in parallel produce an induction passband between two cut-off regions (stop-band), maximum transmitted coefficient Jie in induction passband is limited between two transmission zeros (transmission null) of frequency band, is determined with following related data

Z _1bcot θ ₁+ Z _2bcot θ ₂=0. (formula 1)

In the maximum group delay G of induction passband _dfor

$G_d\≈{2T}_o\frac{Z_o}{Z_{1b}{z}_{2b}/(Z_{1b}+Z_{2b})}\frac{1}{{{\mathrm{\δ}}_o}^2},$ (formula 2)

Wherein, T _ofor signal is by way of the propagation delay time of a wherein non-isometric stub, δ _oit is then the regular frequency range of induction passband.In preferred embodiment, group delay depends on the transmission time expand of each non-isometric stub, the characteristic impedance (characteristic impedance) of normalization induction passband frequency range and main transmission paths and non-isometric stub.

On the high-frequency signals of some special frequency band is tuning, the present invention can be located on a printed circuit board (PCB).As for main transmission path and two to non-isometric stub in parallel, each component can be manufactured via the strip width of change conductor component and length.

As for the complementary line of rabbet joint, be conductor is removed by ground conductor plane formed, form strip non-conductor band.The complementary line of rabbet joint is located at immediately below relevant stub, and stub and the complementary line of rabbet joint are separated with intermediate insulation non-conductive substrate.

Understand detail of the present invention by general known transmission line will benefit to some extent.At this point, please refer to the group delay line elementary cell of Fig. 1, wherein (diagram transmission line is traditional prior art transmission line) 2Z _ib(i=1,2; With 2Z in Fig. 1 _1b, 2Z _2brepresent) be characteristic impedance (characteristic impedance), β _ibfor transmission (propagation constant), and l _ib(with L in Fig. 2 _1b, L _2brepresent) be the physical length of transmission line.Open circuit stub (open stub) 2Z _1band 2Z _2belectrical length is unequal, that is, β _1bl _1b≠ β _2bl _2b, or l _1b≠ l _2bwork as β _1b=β _2b.In the following description, stub 2Z in parallel _ib, 2Z _ibidentical characteristic impedance will change into Z _ibin order to simplify mathematical expression., illustrate for convenience, in Fig. 1 to Fig. 5 of appended embodiment, the present invention is (with reference to figure 1 element Z via a signal source meanwhile _sand signal source shown in Fig. 4 label 1) to output load end (with reference to figure 1 element Z _land Fig. 4 label 5) group delay networking, in illustrated possible embodiments, bar line (stripline) structure of the present invention mainly comprises arranging main transmission path 2, the metal layer at top 11 of signal source, two ends 1 and output load end 5 and associated transport line, intermediate insulating layer 12, Bottom ground layer 13 and the Bottom ground line of rabbet joint 131 (please respectively with reference to figure 2,3 and Fig. 4).Described group delay device comprises a main transmission path 2 (ginseng Fig. 4) and is connected to signal source at two ends (with reference to figure 1 element Z _sand Fig. 4 label 1) and output load end (with reference to figure 1 element Z _land Fig. 4 label 5), two to may be selected to be non-parallel connection open circuit stub group (L _1b, L _1b), (L _2b, L _2b), and two to non-isometric complementary line of rabbet joint group (L _1t, L _1t), (L _2t, L _2t).Each open circuit stub described and the visual needs of the complementary line of rabbet joint are chosen as any one even, non-homogeneous or bending form.

In existing microstrip line construction (microstrip structure), this type of microstrip line construction has a signal layer and a ground plane, but one line structure (stripline structure) then has a signal layer and two external stratum, transmission line representative illustrated is below applicable to microstrip line construction and bar line structure simultaneously.

By prevailing transmission line Z ₀(with reference to figure 1) is towards the input impedance Z of each open circuit stub _{in, i}as shown in the formula

Z _{in, i}=-jZ _icot (β _ibl _ib), (i=1,2). (formula 3)

As a wherein physical length l _ibinput impedance Z _{in, i}be zero, its result is by generation one transmission zero (transmissionzero).When the transmission signal wavelength that open circuit stub is less than 1/4, open circuit stub demonstrates capacitive properties.On the other hand, if the transmission signal wavelength that open circuit stub is greater than 1/4, open circuit stub demonstrates inductive nature.When utilization two has the stub in parallel of different physical length, two transmission zeros can be produced at two individual frequencies.In a frequency between two transmission zeros, the Z of one of them _{in, i}(i=1,2) are inductance type, and another is then condenser type.Work as Z _{in, 1}+ Z _{in, 2}total input impedance of=0, two ribbon feeders is infinitely great, and produces a total transmission at main line.Its result will induce a signal passband between two transmission zeros (transmission null).The signal passband responded to demonstrates high group delay.

In the circuit shown by Fig. 1, scattering parameter (scattering parameter) S ₂₁(or transmission coefficient) is as follows:

$S_{21}=\left[\frac{{2Z}_{\mathrm{in}}}{Z_{\mathrm{in}}+Z_o}\right],$ (formula 4)

Wherein

$Z_{\mathrm{in}}=\left[\frac{1}{\frac{1}{Z_o}+\frac{1}{Z_{\mathrm{in},1}}+\frac{1}{Z_{\mathrm{in},2}}}\right].$ (formula 5)

(formula 3) and (formula 5) is substituted into (formula 4) simultaneously, transmission coefficient S can be obtained ₂₁

$S_{21}=\frac{1}{1+j\frac{Z_o(Z_{1b}\cot {\mathrm{\θ}}_1+Z_{2b}{\mathrm{\θ}}_2)}{{2Z}_{1b}{Z}_{2b}\cot {\mathrm{\θ}}_1\cot {\mathrm{\θ}}_2}},$ (formula 6)

Wherein θ _i=β _ibl _{i b}(i=1,2).

Plural number scattering parameter S ₂₁s can be represented in polar coordinates mode ₂₁=| S ₂₁| ∠ S ₂₁. ∠ S ₂₁for S ₂₁angle (argument) obtained by following formula

${\∠S}_{21}=-\mathrm{\Π}-{\tan }^{-1}\left[\frac{Z_o(Z_{1b}\cot {\mathrm{\θ}}_1+Z_{2b}\cot {\mathrm{\θ}}_2)}{{2Z}_{1b}{Z}_{2b}\cot {\mathrm{\θ}}_1\cot {\mathrm{\θ}}_2}\right].$ (formula 7)

As mentioned above, an induction passband is between two transmission zeros formed by stub in parallel.Elementary cell group delay G _dbe defined as

(formula 8)

Wherein ω is signal frequencies.Group delay G _dby characteristic impedance Z _ib(i=1,2) and transmission line electrical length θ _idetermined, substitute into (formula 8) via by (formula 7), obtain

$G_d=\frac{Z_o{Z}_{1b}{Z}_{2b}\{A-B\}}{{{2Z}_{1b}}^2{Z_{2b}}^2{\cot }^2{\mathrm{\θ}}_1{\cot }^2{\mathrm{\θ}}_2+{{2Z}_o}^2{(Z_{1b}\cot {\mathrm{\θ}}_1+Z_{2b}\cot {\mathrm{\θ}}_2)}^2},$ (formula 9)

Wherein

A=(Z _1bcot θ ₁+ Z _2bcot θ ₂) [(cot θ ₂+ cot ²θ ₁cot θ ₂) T ₁+ (cot θ ₁+ cot ²θ ₂cot θ ₁) T ₂], (formula 9a)

And

B=(Z _1bt ₁+ Z _2bt ₂+ Z _1bt ₁cot ²θ ₁+ Z _2bt ₂cot ²θ ₂) cot θ ₁cot θ ₂. (formula 9b)

The T of (formula 9a) and (formula 9b) ₁and T ₂for travelling to and fro between line l _1band l _2bbetween indivedual time expands, that is, d θ _i/ d ω=T _i(i=1,2).Maximum group delay occurs in all transmission poles.By Z _1bcot θ ₁+ Z _2bcot θ ₂=0 substitutes into (formula 9), obtains

$G_d=\frac{-Z_o}{{2Z}_{1b}{Z}_{2b}\cot {\mathrm{\θ}}_1\cot {\mathrm{\θ}}_2}[Z_{1b}(1+{\cot }^2{\mathrm{\θ}}_1)T_1+Z_{2b}(1+{\cot }^2{\mathrm{\θ}}_2)T_2].$ (formula 10)

For obtaining the reason of the maximum group delay about this dispersion formula transmission line, we simplify its mathematical expression further, when the physical length of a stub is 1/4 wavelength, by generation one transmission zero.In total transmission (totaltransmission) frequency bring out transmission passband two stub electrical length can be following formula

θ ₁=pi/2-δ ₁, θ ₂=pi/2+δ ₂. (formula 11)

δ _i(i=1,2) be total transmission frequency electrical length and by indivedual stub cause electrical length distance between transmission zero frequency.Suppose δ ₁=δ ₂=δ, (formula 10) can be reduced to following formula further

$G_d=\frac{Z_o\left[(Z_{1b}{T}_2+Z_{2b}{T}_1)(1+{\tan }^2\mathrm{\δ})\right]}{{2Z}_{1b}{Z}_{2b}{\tan }^2\mathrm{\δ}}.$ (formula 12)

For a narrower induction passband, tan δ ≈ δ and tan ²δ <<1.In this case, the group delay of (formula 10) becomes following formula

$G_d\&ap;\frac{Z_o}{{2Z}_{1b}{Z}_{2b}{\mathrm{\&delta;}}^2}[Z_{1b}{T}_1+Z_{2b}{T}_2].$ (formula 13)

T need be mentioned _i(i=1,2) are the propagation delay time of signal through stub line.Suppose δ 1=δ 2=δ o/2andT ₁=T ₂=T _o, (formula 13) can be simplified to following formula further

$G_{d,\mathrm{narrowband}}\&ap;{2T}_o\frac{Z_o}{Z_{1b}{z}_{2b}/(Z_{1b}+Z_{2b})}\frac{1}{{{\mathrm{\&delta;}}_o}^2},$ (formula 14)

Wherein, T _othe propagation delay time by 1/4 wavelength, δ _ois be by two stubs cause regular frequency range between two transmission zeros.

Separately, as shown in Figure 5, described elementary cell is with component Z ₁, Z ₂... .., Z _n(n is positive integer) cascade connects and composes group's delay linear system.

Meanwhile, the complementary line of rabbet joint disclosed be used to change induction produce limited frequency band passband become all-pass band (all pass-band), that is ︱ S ₂₁︱=1.

Above embodiment only with illustrating the present invention for convenience, is not in a limitative way, and for haveing the knack of the various Simple transformed and modification that this skill personage can do according to illustrated embodiment, all must include in following claim.

Claims (8)

1. a dispersion type micro-wave group delay line, it is characterized in that, at least comprise one by the elementary cell of a signal source (1) to output load end (5) the tuning signal transmission group delay time, described elementary cell comprises a main transmission path (2) for input and output signal, and two to non-isometric open circuit stub ((L _1b, L _1b), (L _2b, L _2b)) be positioned to form induction passband in the middle of main transmission path, two to the non-isometric complementary line of rabbet joint ((L _1t, L _1t), (L _2t, L _2t)) be positioned at the ground plane of microstrip line construction.

2. dispersion type micro-wave group delay line as claimed in claim 1, is characterized in that, each open circuit stub of described elementary cell and the complementary line of rabbet joint are even, non-homogeneous and bending any one form wherein along transmission line.

3. dispersion type micro-wave group delay line as claimed in claim 1, is characterized in that, each open circuit stub of described elementary cell is set to multiple field and each complementary line of rabbet joint is set to multiple field.

4. dispersion type micro-wave group delay line as claimed in claim 1, is characterized in that, described elementary cell parallel connection open circuit stub characteristic impedance Z _1b, Z _2belectrical length θ ₁, θ ₂, wherein θ ₁≠ θ ₂following formula is met in working band:

Z _1bcotθ ₁+Z _2bcotθ ₂＝0。

5. dispersion type micro-wave group delay line as claimed in claim 1, is characterized in that, the main transmission path of described elementary cell (2) and open circuit stub ((L _1b, L _1b), (L _2b, L _2b)) be the printed circuit cable of a printed circuit board (PCB) signal layer, the complementary line of rabbet joint ((L _1t, L _1t), (L _2t, L _2t)) for removing the line of rabbet joint region of conductor at ground plane.

6. dispersion type micro-wave group delay line as claimed in claim 1, it is characterized in that, described elementary cell is with component Z ₁, Z ₂... .., Z _n, wherein n is positive integer, and cascade connects and composes group's delay linear system.

7. a dispersion type micro-wave group delay line, is characterized in that, comprises an elementary cell, and described elementary cell is made up of the complementary line of rabbet joint most open-circuit stub and majority, wherein, and open circuit stub ((L _1b, L _1b) ... .., (L _nb, L _nb)), the wherein printed circuit cable of n to be positive integer be a printed circuit board (PCB) signal layer, the complementary line of rabbet joint ((L _1t, L _1t) ... .., (L _nt, L _nt)) for removing the line of rabbet joint region of conductor at ground plane.

8. a dispersion type micro-wave group delay line, it is characterized in that, at least comprise one by the elementary cell of a signal source (1) to output load end (5) the tuning signal transmission group delay time, described elementary cell comprises a main transmission path (2) for input and output signal, and two to non-isometric open circuit stub ((L _1b, L _1b), (L _2b, L _2b)) be positioned to form induction passband in the middle of main transmission path, two to the non-isometric complementary line of rabbet joint ((L _1t, L _1t), (L _2t, L _2t)) be arranged in bar line structure any layer of upper and lower two-layer ground plane.