CN102522618A - Active left-handed transmission line formed by lumped element and diode - Google Patents

Abstract

The invention relates to an active left-handed transmission line formed by a lumped element and a diode and belongs to the technical field of microwaves. The transmission line comprises an SMA (Shape Memory Alloy) joint and micro-strip lines and is formed in a mode that N stages of units are cascaded. Each active left-handed transmission line unit consists of a series chip capacitor, a radio frequency choke inductor, a bias voltage, a negative differential resistance diode, a parallel chip inductor, a metal through hole, a dielectric substrate and a metal earth plate. The active left-handed transmission line units are connected through the micro-strip lines. An anode of each bias voltage is connected with a metal wire on the top layer of the joint of the corresponding micro-strip line and a cathode of the bias voltage is connected with the corresponding metal earth plate on the bottom layer of the micro-strip line. Each bias voltage is connected with a radio frequency signal transmission part of the active left-handed transmission line through the corresponding radio frequency choke inductor. The active left-handed transmission line not only has the characteristics that the active left-handed transmission line has the advantages of wide band, small size and simple structure, is easy to match and is easy for circuit integration, but also has the characteristic of net gain, i.e. transmission amplification, and can be applied to design of an antenna, a filter, a power divider, a phase shifter, a directional coupler, an amplifier, a sub-wavelength resonator, a perfect lens and the like.

Description

The active left hand transmission line that constitutes by lamped element and diode

Technical field

The invention belongs to microwave technical field, particularly a kind of utilize broadband that lamped element and negative differential resistance diode constitute, small size, simple in structure, be prone to coupling, be easy to the integrated active left hand transmission line of circuit.

Background technology

At present, be two kinds of basic skills of design metamaterials based on resonance structure and antithesis transmission line.Can be known by the Maxwell equation of Theory of Electromagnetic Field and the pro forma similitude of telegraph equation of transmission line theory: material behavior can be described by electromagnetic property parameter (dielectric constant, magnetic permeability, refractive index and wave impedance) or linear electrical parameter (impedance, admittance, propagation constant, characteristic impedance) fully equivalently, and can transform each other.People such as Smith produced first metamaterials (D RSmith, W J Padilla, D C Vier based on resonance structure in 2000; S C Nemat-Nasser, and S Schultz, Composite medium withsimultaneously negative permeability and permittivity.Physical Review Letters; 2000; Vol.84, no.18, pp.4184-4187.).2002, Itoh (C Caloz and T Itoh, Application ofthe Transmission Line Theory of Left-Handed (LH1) Materials to the Realization ofa Microstrip LII Transmission Line.IEEE International Symposium on Antennas andPropagation Digest; San Antonio, USA, 2002; Pp.412-415.); Oliner (A A Oliner, APlanar Negative-Refractive-Index Medium Without Resonant Elements.CNCIUSNC URSINational Radio Science Meeting, San Antonio; USA; 2002, p.41.) and Eleftheriadis (AK Iyer and G V Eleftheriades, Negative Refractive Index Metamaterials Supporting 2-DWaves.IEEE International Symposium on Microwave Theory and Techniques Digest; Seattle; USA, 2002, pp.1067-1070.) three independent respectively new methods that propose to realize metamaterials of group with transmission line.This based on the transmission-line equivalent circuit model; Utilize the principle of duality; On traditional right hand transmission line, load the left hand transmission line of series capacitance and shunt inductance design periodically; With respect to metamaterials based on resonance structure, have complanation, bandwidth, be easy to advantages such as circuit is integrated, cause extensive concern in microwave technical field.

The a lot of peculiar electromagnetic property of metamaterials can apply to the multiple application that traditional nature material is difficult to realize.Yet, because being inferior wavelength unit combination by the manual construction of arranging cycle or aperiodic, metamaterials forms, the influence of its loss is the difficult problem of individual extensive concern always.Stockman is at document M I Stockman, Criterion for negative refractionwith low optical losses from a fundamental principle of causality.Physical ReviewLetters, 2007; Vol.98, pp.177404. and document M I Stockman, Spaser action; Losscompensation; And stability in plasmonic systems with gain.Physical Review Letters, 2011, vol.106; Pp.156802. the utilization causality has proved that the LHM with net gain can't realize in, has caused very big dispute in academia.At present, the active metamaterials of net gain be can realize having, one of Electromagnetic Field and Microwave Technology and physics field bone of contention become.

Summary of the invention

To the loss problem of passive metamaterials, the present invention provides a kind of active left hand transmission line that is made up of lamped element and diode.This active left hand transmission line not only has broadband, little, simple in structure, the easy coupling of size, is easy to the integrated characteristics of circuit; Also has net gain simultaneously; The characteristic that i.e. transmission is amplified can be applied to designs such as antenna, filter, power splitter, phase shifter, directional coupler, amplifier, inferior wavelength resonator, perfect lens.

For achieving the above object, the technical scheme that the present invention adopted is:

The active left hand transmission line that should be made up of lamped element and diode comprises sub-miniature A connector (1) and microstrip line (2); It is characterized in that: this active left hand transmission line forms by the N level is unit cascaded; N is the integer more than or equal to 1; Each active left hand transmission line unit is made up of series connection patch capacitor (3), radio frequency choke induction (4), bias voltage (5), negative differential resistance diode (6), parallelly connected chip inductor (7), metallic vias (8), medium substrate (9) and metal ground plate (10), and it links to each other by microstrip line; The bias voltage positive pole links to each other with a microstrip line junction top wire, and negative pole links to each other with microstrip line underlying metal ground plate, and bias voltage partly links to each other through the radio frequency choke induction with active left hand transmission line radio signal transmission.

RT/duroid 5880 sheet materials that said active left hand transmission line medium substrate adopts ROGERS CORPORATION to produce.

The negative differential resistance diode of said active left hand transmission line is fashionable in series connection to be the active left hand transmission line of magnetic, is electric active left hand transmission line when parallel connection inserts, and is the active transmission line of electromagnetism when connection in series-parallel inserts simultaneously.

The negative differential resistance diode of said active left hand transmission line adopts tunnel diode TD261A.

Beneficial effect

The invention solves the big problem of passive metamaterials loss, utilize lamped element and negative differential resistance diode design to realize having the active left hand transmission line of net gain.Project organization of the present invention is simple, bandwidth, size are little, be prone to coupling, be easy to circuit integrated, also have the electromagnetic transmission negative simultaneously and move the characteristic of amplifying with signal.The present invention has proved that clearly the LHM with net gain can design and realize.

In the transmission band, attenuation constant is a negative value leftward in the present invention, and the electromagnetic transmission amplification characteristic is obvious, and matching performance is good.

Structure of the present invention is changeable; Can be directed against different application; Select distributed constant or lamped element to realize the left hand characteristic transmission line, also can select negative differential resistance diode or other transistors that the loss balancing even the transmission enlarging function of metamaterials are provided with signal amplifying function.

The present invention can be widely used in designs such as antenna, filter, power splitter, phase shifter, directional coupler, amplifier, inferior wavelength resonator, perfect lens.

[description of drawings]

Fig. 1 is an embodiment of the invention structure vertical view;

Fig. 2 is an embodiment of the invention structure side view;

Fig. 3 is a dielectric constant magnetic permeability graph of a relation of the present invention;

Fig. 4 is an active left hand transmission line periodic unit equivalent circuit diagram according to the invention;

Fig. 5 is an embodiment of the invention tunnel diode TD261A equivalent circuit diagram;

Fig. 6 is embodiment of the invention tunnel diode TD261A VA characteristic curve figure;

Fig. 7 is an embodiment of the invention uniform dielectric coefficient | H _i| with frequency variation curve figure;

Fig. 8 is that embodiment of the invention scattering parameter is with frequency variation curve figure;

Fig. 9 is that the embodiment of the invention is with frequency variation curve figure;

Figure 10 is that the relative effective dielectric constant of the embodiment of the invention is with frequency variation curve figure;

Figure 11 is that the relative equivalent permeability of the embodiment of the invention is with frequency variation curve figure;

Figure 12 is that embodiment of the invention propagation constant is with frequency variation curve figure;

Figure 13 is that embodiment of the invention characteristic impedance is with frequency variation curve figure;

Figure 14 is that embodiment of the invention equivalent refractive index is with frequency variation curve figure.

Among the figure:

1-SMA joint, 2-microstrip line, 3-patch capacitor, 4-radio frequency choke induction, 5-bias voltage junction 6-negative differential resistance diode, 7-chip inductor, 8-metallic vias, 9-medium substrate, 10-metal ground plate.

[embodiment]

Below in conjunction with accompanying drawing and embodiment the present invention is further described.Be noted that said embodiment only is regarded as illustration purpose, rather than limitation of the present invention.

Can find out that like Fig. 1 and Fig. 2 the embodiment of the invention is " magnetic " active left hand transmission line.It is characterized in that: input/output port is sub-miniature A connector 1 and feed microstrip line 2, and feed microstrip line length is 10mm, characteristic impedance Z _CBe chosen for 50 Ω; Active left hand transmission line is by 5 unit cascaded forming; Each element length is P=6mm, in the frequency range of 1.79～9.42GHz, satisfies equivalent uniform dielectric condition; Active left hand transmission line unit is by the patch capacitor C of series connection _LThe chip inductor L of=2.2pF and parallel connection _L=4.7nH is used for the negative differential resistance diode TD261A that loss balancing even transmission are amplified, and the radio frequency choke induction 4 of isolating radiofrequency signal is 27nH, and the parasitic capacitance C that connects the microstrip line generation of lamped element and negative differential resistance diode _RWith stray inductance L _RForm.

The equivalent electric circuit of said active left hand transmission line unit is as shown in Figure 4, L _RAnd C _RParasitic right hand inductance and right hand electric capacity for the microstrip line generation; C _LAnd L _LFor be used to design the left hand electric capacity and the left hand inductance of left hand characteristic transmission line through the principle of duality, can realize by distributed constant or lamped element.The present invention selects lamped element for use.R _dAnd G _dBe the equivalent resistance behind the access negative differential resistance diode.For different bias voltage, R _dAnd G _dAlso inequality, can be respectively positive and negative or zero, on the occasion of represent loss, negative value representative gain, zero then representative nothing consumes.

The series impedance and the shunt admittance of said active left hand transmission line unit equivalent electric circuit are respectively:

$Z_{\mathrm{se}}=R_d+j(\mathrm{\ω}{L}_R-\frac{1}{\mathrm{\ω}{C}_L})---\left(1\right)$

$Y_{\mathrm{sh}}=G_d+j(\mathrm{\ω}{C}_R-\frac{1}{\mathrm{\ω}{L}_L})---\left(2\right)$

Said active left hand transmission line element length P needs much smaller than operation wavelength, at least should be less than the quarter-wave guide wavelength:

$P<\frac{{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="4"\; label="g"\; filenames="HDA0000126868220000032.png,HDA0000126868220000033.png"\; state="\{\{state\}\}">g</figure-callout>}}}{4}=\frac{\mathrm{\&pi;}}{2\mathrm{\&beta;}}---\left(3\right)$

According to EFFECTIVE MEDIUM THEORY, establish uniform dielectric coefficient H _i=2 β P/ π, when this coefficient absolute value less than 1 the time, metamaterials can be regarded equivalent uniform dielectric as.

According to the Maxwell equation of Theory of Electromagnetic Field and the pro forma similitude of telegraph equation of transmission line theory, said active left hand transmission line characteristic can be by electromagnetic property parameter (effective dielectric constant ε _Eff, equivalent permeability μ _Eff, equivalent refractive index N _EffWith equivalent wave impedance Z ₀) and linear electrical parameter (impedance Z _Se, admittance Y _Sh, propagation constant γ=α+j β, characteristic impedance Z ₀) describe fully equivalently, and can transform each other, the relation between them is following:

${\mathrm{\&epsiv;}}_{\mathrm{eff}}=\frac{{\mathrm{<figure-callout\; id="0"\; label="N\; eff\; Z"\; filenames="HDA0000126868220000013.png,HDA0000126868220000042.png"\; state="\{\{state\}\}">N</figure-callout>}}_{\mathrm{eff}}}{Z_{}}=Y_{\mathrm{sh}}/\left(\mathrm{jP\&omega;}\right)---\left(4\right)$

μ _eff＝N _effZ ₀＝Z _se/(jPω) (5)

$N_{\mathrm{eff}}=n_{\mathrm{eff}}+j{\mathrm{\&kappa;}}_{\mathrm{eff}}=\&PlusMinus;\sqrt{{\mathrm{\&epsiv;}}_r{\mathrm{\&mu;}}_r}=\&PlusMinus;c\sqrt{{\mathrm{\&epsiv;}}_{\mathrm{eff}}{\mathrm{\&mu;}}_{\mathrm{eff}}}=\mathrm{\&gamma;}/\left({\mathrm{jk}}_0\right)---\left(6\right)$

$\mathrm{\&gamma;}=\mathrm{\&alpha;}+\mathrm{j\&beta;}=\&PlusMinus;\sqrt{Z_{\mathrm{se}}{Y}_{\mathrm{sh}}}=\&PlusMinus;\mathrm{j\&omega;}\sqrt{{\mathrm{\&epsiv;}}_{\mathrm{eff}}{\mathrm{\&mu;}}_{\mathrm{eff}}}={\mathrm{jk}}_0{N}_{\mathrm{eff}}---\left(7\right)$

${\mathrm{<figure-callout\; id="0"\; label="Z"\; filenames="HDA0000126868220000013.png,HDA0000126868220000042.png"\; state="\{\{state\}\}">Z</figure-callout>}}_0=\&PlusMinus;\sqrt{\frac{Z_{\mathrm{se}}}{Y_{\mathrm{sh}}}}=\&PlusMinus;\sqrt{\frac{{\mathrm{\&mu;}}_{\mathrm{eff}}}{{\mathrm{\&epsiv;}}_{\mathrm{eff}}}}=\frac{Z_{\mathrm{se}}}{\mathrm{\&gamma;}}---\left(8\right)$

ε in the formula _Eff=ε _rε ₀, μ _Eff=μ _rμ ₀, k ₀(=ω/c) is the free space wave number, and ω is an angular frequency, and c is the light velocity in the vacuum.

Can know by equation (4) and (5): work as R _dBe negative value, the imaginary part of the equivalent permeability of this transmission line be on the occasion of, be active magnetic permeability, be called " magnetic " active left hand transmission line; Work as G _dBe negative value, the imaginary part of the effective dielectric constant of this transmission line be on the occasion of, be active dielectric constant, be called " " active left hand transmission line; Work as R _dAnd G _dBe negative value simultaneously, the equivalent permeability of this transmission line and the imaginary part of effective dielectric constant be on the occasion of, be called " electromagnetism " active left hand transmission line.

Sign in equation (6)-(8) can be come by the symbol of attenuation constant α all to confirm.Concrete steps are following:

Step 1, confirm the symbol of attenuation constant α.From the viewpoint of power transfer, utilization microwave network scattering parameter is theoretical, is active left hand transmission line input power P (0) and the satisfied following relation of output power P (L) of L for arbitrary length:

$\frac{P\left(L\right)}{P\left(0\right)}=e^{(-2\mathrm{\&alpha;L})}=\frac{{\mathrm{<figure-callout\; id="21"\; label="S"\; filenames="HDA0000126868220000032.png,HDA0000126868220000033.png"\; state="\{\{state\}\}">S</figure-callout>}}_{21}^2}{1-{\mathrm{<figure-callout\; id="11"\; label="S"\; filenames="HDA0000126868220000032.png"\; state="\{\{state\}\}">S</figure-callout>}}_{11}^2}---\left(9\right)$

Can know by equation (9); When attenuation constant α get on the occasion of, represent loss; When attenuation constant α gets negative value, represent gain; When attenuation constant α value is zero, represent and do not have consumption.

Step 2, by the real part attenuation constant α of propagation constant, according to gram Georg Lammers-Ke Lenixi (Kramers-Kronig) relation, can confirm the symbol of the imaginary part phase-shift constant β of propagation constant.

Step 3, after propagation constant is confirmed, equivalent refractive index N _Eff=γ/(jk ₀), wave impedance or characteristic impedance Z ₀=Z _Se/ γ just can confirm.

The active left hand transmission line of the embodiment of the invention described " magnetic " comprises: select the medium substrate material 9 of RT/duroid 5880 sheet materials of ROGERS CORPORATION's product as the embodiment of the invention; Substrate dielectric constant is 2.2; Loss angle tangent is 0.0009, and thickness is 0.7874mm; The microstrip line metal conductor layer comprises conduction band and metal ground plate 10, and thickness is 0.035mm, and conductivity is 5.8 * 10 ⁷S/m; Microstrip line conduction band bandwidth is 2.4mm, and characteristic impedance is 50 Ω; The diameter of metallic vias is chosen for 0.6mm; The transmission line negative differential resistance diode selecting tunnel diode TD261 access of connecting; The negative differential resistance biased electrical nip of tunnel diode TD261 is 0.08-0.40V; Bias voltage 5 is chosen as 0.2V, drops on tunnel diode TD261 negative differential resistance service area.

The concrete execution in step of making the active left hand transmission line of the embodiment of the invention described " magnetic " is following:

Step 1, is as required confirmed operating frequency f ₀, make active left hand transmission line at f ₀The frequency phase-shift constant be zero, less than f ₀Phase-shift constant is a negative value, greater than f ₀Phase-shift constant be on the occasion of.

Step 2, the parasitic equivalent inductance L of calculating _RAnd capacitor C _R, they can be tried to achieve by the physical dimension of microstrip line.The conduction band width W of known microstrip line, thickness t, dielectric substrate thickness h and substrate dielectric constant ε _r, its characteristic impedance Z _cWith effective dielectric constant ε _eBe respectively

$Z_c=\sqrt{\frac{L_R}{C_R}}=\left\{\begin{array}{cc}\frac{60}{\sqrt{{\mathrm{\&epsiv;}}_{\mathrm{eff}}}}\ln (\frac{8h}{W}+\frac{W}{4h})& \frac{W}{h}<1\\ \frac{120\mathrm{\&pi;}}{\sqrt{{\mathrm{\&epsiv;}}_{\mathrm{eff}}}[\frac{W}{h}+1.393+\frac{2}{3}\ln (\frac{W}{h}+1.444)]}& \frac{W}{h}\&GreaterEqual;1\end{array}\right.---\left(10\right)$

${\mathrm{\&epsiv;}}_e=c^2{L}_R{C}_R=\left\{\begin{array}{cc}\frac{{\mathrm{\&epsiv;}}_r+1}{2}+\frac{{\mathrm{\&epsiv;}}_r-1}{2}[\frac{1}{\sqrt{1+12h/W}}+0.041{(1-W/h)}^2]& \frac{W}{h}<1\\ \frac{{\mathrm{\&epsiv;}}_r+1}{2}+\frac{{\mathrm{\&epsiv;}}_r-1}{2}\frac{1}{\sqrt{1+12h/W}}& \frac{W}{h}\&GreaterEqual;1\end{array}\right.---\left(11\right)$

When t ≠ 0, and t＜h, during t＜W/2, corresponding correction formula is:

$\frac{W_e}{h}=\frac{W}{h}+\frac{1.25t}{\mathrm{\&pi;h}}(1+\ln \frac{2x}{t})---\left(12\right)$

In the formula

$x=\left\{\begin{array}{cc}h& W/h\&GreaterEqual;1/\left(2\mathrm{\&pi;}\right)\\ 2\mathrm{\&pi;W}& W/h<1/\left(2\mathrm{\&pi;}\right)\end{array}\right.---\left(13\right)$

Thereby obtain the parasitic equivalent inductance L that microstrip line brings _RAnd capacitor C _RFor

$C_R=\frac{\sqrt{{\mathrm{\&epsiv;}}_e}}{{\mathrm{cZ}}_c}---\left(14\right)$

$L_R=Z_c^2{C}_R=\frac{\sqrt{{\mathrm{\&epsiv;}}_e}{Z}_c}{c}---\left(15\right)$

Step 3, calculating left hand equivalent circuit parameter C _LAnd L _L, it is satisfied:

${\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="HDA0000126868220000013.png,HDA0000126868220000042.png"\; state="\{\{state\}\}">f</figure-callout>}}_0=\frac{1}{2\mathrm{\&pi;}\sqrt{C_R{L}_L}}=\frac{1}{2\mathrm{\&pi;}\sqrt{C_L{L}_R}}---\left(16\right)$

Step 4, according to the equivalent electric circuit of negative differential resistance diode; Consider the influence of negative differential resistance diode stray inductance and electric capacity to left hand transmission line; Revise the equivalent circuit parameter of gained in step 1, the step 2, thereby obtain to revise the capacitance and the inductance value of back lump paster.

Step 5, utilize the microwave simulation software to carry out the associative simulation of electromagnetism and circuit.For example use Ansoft HFSS of 3 D electromagnetic all-wave simulation software and the grade simulated software Agilent of Circuits and Systems ADS etc., active left hand transmission line is carried out the associative simulation of electromagnetism and circuit and optimizes, make this active left hand transmission line less than f ₀Frequency range have the function that left hand characteristic, net gain and propagation are amplified, and matching performance is good.The embodiment of the invention is utilized HFSS and ADS associative simulation, at first in HFSS, carries out the all-wave Electromagnetic Simulation, all replaces with Lumped Port earlier at lamped element and negative differential resistance diode junction.For example for the active left hand transmission line of a unit; In the simulation model of HFSS; Except two Wave Port that are used to encourage, also have four Lumped Port that are used to represent to be about to add series connection patch capacitor, parallelly connected chip inductor, radio frequency choke induction and negative differential resistance diode.Therefore after emulation finishes, the Touchstone file that it is S6P that a unit active left hand transmission line HFSS model of 3 D electromagnetic all-wave emulation can be derived a suffix; The Touchstone file that it is SnP that the active left hand transmission line HFSS model of N unit then can be derived a suffix, the n=6N here.The Touchstone file that then emulation of 3 D electromagnetic all-wave is obtained imports among the ADS.For making emulation more near truth, when adding lumped elements, the Touchstone file that its model all provides with businessman (suffix is S2P) joins among the ADS.Negative differential resistance diode model is then simulated by businessman's VA characteristic curve and equivalent circuit diagram jointly; The method that its voltage-current characteristic adopts SDD (symbolically defined device) to add equation is described; The equation curve is as shown in Figure 6, and equivalent circuit values is L among Fig. 5 _S=1.5nH, R _S=7 Ω, C _P=1pF.At last, the powerful parameter optimization function of utilizing HFSS and ADS to carry designs this active left hand transmission line less than f ₀Frequency range attenuation constant and phase-shift constant be negative value all, and have good matching performance.

Step 6, in simulation process and after emulation finishes, to the whole flow process of emulation with the result verifies and analytical calculation.It should be noted that especially:, need the transmission line feed that two ends are made up of sub-miniature A connector (1) and microstrip line (2) is gone to embed processing for obtaining active left hand transmission line characteristic.

Step 7, according to the simulation result of active left hand transmission line, the fabrication and processing domain is bought required lamped element and negative differential resistance diode, carries out welded and installed.

Step 8, active left hand transmission line is measured, comprised the voltage-current characteristic of using the analyzing parameters of semiconductor appearance to measure the negative differential resistance diode; Use vector network analyzer to measure S parameter under different bias voltages; And use frequency spectrograph to analyze characteristics such as active left hand transmission line is non-linear under different bias voltages, high order harmonic component.After need going embedding to wait processing equally, obtain the measurement result of active left hand transmission line.Then, the similarities and differences of analysis to measure result and simulation result judge whether to meet design requirement, to determine whether and need design again and emulation.

Fig. 7 is an embodiment of the invention uniform dielectric coefficient | H _i| with the curve chart of frequency change, as can be seen from the figure, in the frequency range of 1.79～9.42GHz, | H _i|＜1, satisfy equivalent uniform dielectric condition.

Fig. 8 is the curve chart of the scattering parameter of the embodiment of the invention when bias voltage is set to 0.2V with frequency change, and figure can know the active left hand transmission line that is designed, its S thus ₂₁The mould value between 1.7-4.7GHz greater than 1, be illustrated in this band frequency scope, the electromagnetic energy through this active transmission line has obtained amplification.

Fig. 9 is the curve chart of the embodiment of the invention

with frequency change.In frequency range less than 4.9GHz; The value of is all greater than 1; Representing this transmission line is active transmission line, and attenuation constant α gets negative value this frequency range planted agent; Frequency range greater than 4.9GHz; The value of

is less than 1, attenuation constant α this frequency range planted agent get on the occasion of; And at this frequency of 4.9GHz; The value of

is 1, and attenuation constant α should get null value.

Can know that by transmission line theory characteristic impedance and propagation constant are two important basic parameters in the transmission line.Figure 13 is that the impedance of embodiment of the invention equivalent characteristic is with frequency variation curve figure.Figure 12 is an embodiment of the invention propagation constant, comprises attenuation constant and phase-shift constant, with frequency variation curve figure.The symbol of attenuation constant is through

and 1 size comparison obtains; As can be seen from the figure; Less than the 4.9GHz attenuation constant is negative; For just, equaling the 4.9GHz attenuation constant is zero greater than the 4.9GHz attenuation constant.Phase-shift constant is zero at 3.69GHz, and the phase velocity infinity of electromagnetic wave propagation and group velocity are infinity for just at this frequency guide wavelength; During less than this frequency, phase-shift constant is for negative, and electromagnetic wave propagation phase velocity and group velocity are in the opposite direction, are the left hand district; During greater than this frequency, phase-shift constant is for just, and the electromagnetic wave propagation phase velocity is identical with the group velocity direction, is right hand region.

In the frequency range of 1.79～9.42GHz, said active left hand transmission line can be regarded equivalent uniform dielectric as for the embodiment of the invention, can be by electromagnetic property parameter (effective dielectric constant ε _Eff, equivalent permeability μ _Eff, equivalent refractive index N _EffWith equivalent wave impedance Z ₀) describe.Figure 10 is that embodiment of the invention effective dielectric constant is with frequency variation curve figure.Figure 11 is that embodiment of the invention equivalent permeability is with frequency variation curve figure.Figure 14 provides embodiment of the invention equivalent refractive index, comprises its real part and imaginary part, with frequency variation curve figure.From figure, can know this active left hand transmission line, equivalent permeability μ _EffImaginary part be on the occasion of, be " magnetic " active left hand transmission line; Less than 3.69GHz is the left hand district; Less than 4.9GHz is the active gain district; Be the transmission amplification region at 1.7-4.7GHz.

Such scheme is an example of active left hand transmission line only; Be not that the present invention is done any pro forma qualification; Appoint those skilled in the art can be, utilize the technology contents of above-mentioned announcement to change or be modified to the equivalent instance of equivalent variations according to actual conditions.But, everyly not breaking away from technical scheme content of the present invention, any simple modification, equivalent variations and modification according to technical spirit of the present invention is done above instance all still belong in the scope of technical scheme of the present invention.

Claims (6)

1. the active left hand transmission line that constitutes by lamped element and diode; Comprise sub-miniature A connector (1) and microstrip line (2); It is characterized in that: this active left hand transmission line forms by the N level is unit cascaded; N is the integer more than or equal to 1; Each active left hand transmission line unit is made up of series connection patch capacitor (3), radio frequency choke induction (4), bias voltage (5), negative differential resistance diode (6), parallelly connected chip inductor (7), metallic vias (8), medium substrate (9) and metal ground plate (10), and it links to each other by microstrip line; The bias voltage positive pole links to each other with a microstrip line junction top wire, and negative pole links to each other with microstrip line underlying metal ground plate, and bias voltage partly links to each other through the radio frequency choke induction with active left hand transmission line radio signal transmission.

2. the active left hand transmission line that is made up of lamped element and diode as claimed in claim 1 is characterized in that: RT/duroid 5880 sheet materials that said active left hand transmission line medium substrate adopts ROGERS CORPORATION to produce.

3. the active left hand transmission line that constitutes by lamped element and diode as claimed in claim 2; It is characterized in that: the negative differential resistance diode of said active left hand transmission line is fashionable in series connection to be the active left hand transmission line of magnetic; Being electric active left hand transmission line when parallel connection inserts, is the active transmission line of electromagnetism when connection in series-parallel inserts simultaneously.

4. the active left hand transmission line that is made up of lamped element and diode as claimed in claim 3 is characterized in that: the negative differential resistance diode of said active left hand transmission line adopts tunnel diode TD261A.

5. the active left hand transmission line that is made up of lamped element and diode as claimed in claim 4 is characterized in that: the length P of each active left hand transmission line unit is for time wavelength, less than the quarter-wave guide wavelength.

6. the active left hand transmission line that constitutes by lamped element and diode as claimed in claim 5; It is characterized in that: said active left hand transmission line is realized negative magnetic permeability through series capacitance; Shunt inductance is realized negative dielectric constant; Through regulating the feed voltage of negative differential resistance diode, make it be operated in negative differential resistance region energy is provided.

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