CN102361533B - Electromagnetic band gap structure for optimizing power distribution network of PCB (printed circuit board) and construction method thereof - Google Patents
Electromagnetic band gap structure for optimizing power distribution network of PCB (printed circuit board) and construction method thereof Download PDFInfo
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Abstract
The invention discloses an electromagnetic band gap structure for optimizing a power distribution network of a PCB (printed circuit board), and the electromagnetic band gap structure is of a periodic structure. The shape of a periodic unit is formed by four large-size narrow-bridge-shaped connecting metal branches, eight small-size narrow-bridge-shaped connecting metal branches with same shapes, and square metal patches. All the periodic units are connected by utilizing the narrow-bridge-shaped connecting metal branches of all the edges. A construction method comprises the following seven main steps: (1) establishing a periodic structure unit layer of a zero-thickness composite coplanar EBG (Electromagnetic Band Gap) layer; (2) establishing a medium layer of the periodic structure units of the composite coplanar EBG layer; (3) establishing a dispersion diagram simulation model of the composite coplanar EBG periodic structure units; (4) carrying out periodic prolongation on the periodic structure units of the composite coplanar EBG layer obtained by the step (1) along the X and Y directions to obtain the composite coplanar EBG layer; (5) establishing a medium layer of an EGB structure and embedding the composite coplanar EBG structure layer into a substrate of a medium; (6) adding a simulation port to calculate an S parameter of the EBG structure; and (7) practically plating and testing the transmission characteristic of the composite coplanar EBG structure.
Description
(1) technical field
The present invention relates to a kind of electromagnetic bandgap structure and construction method thereof of optimized PCB power distribution network.This electromagnetic bandgap structure can suppress high frequency and the hyperfrequency power supply noise of high speed circuit power distribution network (" power distribution network " is hereinafter to be referred as PDN).It belongs to the high speed circuit microwave technical field.
(2) background technology
Along with the progress of semiconductor technology and continuing to bring out of circuit new technology, Circuits System is towards the trend development of high-speed, high density, high power consumption, low-voltage and large electric current.The reliability and stability of Circuits System work become the key of high speed circuit development, and this has just proposed severe challenge for the power distribution network design of contemporary electronic system with the Power Integrity analysis.
PDN is electronic system the most complicated the hugest interconnect architecture, and on system, all devices all are connected on PDN directly or indirectly, and approximately 40% interconnected space is used for PDN placement-and-routing.The design of PDN is directly related with circuit power integrality (PI), also with signal integrity (SI), with electromagnetic interference (EMI), closely is connected.Transistorized synchro switch behavior needs on pcb board is drawn a large amount of transient currents, has caused the fluctuation of power supply rail voltage, and voltage fluctuation is propagated and formed the distributed electrical source noise on PDN.Power supply noise is coupled on holding wire by PDN, causes signal distortion, and eye pattern is closed.The resonant cavity that the power supply ground level forms is easily encouraged and resonance occurs by the return current of high-speed digital signal and simultaneous switching noise (SSN), causes serious electromagnetic radiation on power supply ground level edge.
Current research to PI does not form a complete system, and research direction is mainly modeling and analysis, the analysis of decoupling capacitor network and four aspects of electromagnetic compatibility of design, mains switch noise and PCB of power plane.For optimization and the design of PDN, the decoupling capacitor network is its important component part, and the design of decoupling network is also the design difficulty of PDN.How distributing the position of decoupling capacitor, decoupling capacitor whether to affect the problems such as decoupling effect is bone of contention.The inhibition of SSN is also an important content of PDN design.Developed at present multiple SSN inhibition method: (1) adds discrete decoupling capacitor; (2) adopt embedded decoupling capacitor; (3) optimize the position of via hole; (4) the power supply ground level is cut apart; (5) increase resistive matching element at the PCB edge; (6) adopt and diminish element; (7) design via hole guard rail; (8) adopt difference signaling etc.But these methods are Shortcomings when suppressing SSN, as the stray inductance of decoupling capacitor, makes capacitor increase and make noise suppressed lose efficacy in the impedance of high frequency, and the decoupling scope of general Surface Mount encapsulation decoupling capacitor is in the 100MHz left and right.Introduce in recent years the method that a kind of employing electromagnetic bandgap structure (EBG structure) suppresses power supply noise in PDN, and derived multiple broadband EBG structure and design and analysis method thereof.
The EBG structure is the periodic structure with band resistance characteristic, can adopt metal, medium, ferromagnetic or ferroelectric implantation host material, perhaps directly by various material periodic arrangement, is formed.The EBG structure that proposes both at home and abroad at present is varied,, such as in the medium substrate middle punch, perhaps fills other materials or metal in medium substrate, on the microstrip circuit surface, around redundancy section, forms EBG structure etc.The EBG structure is incorporated in the noise suppressed of power supply ground level and suppresses SSN and its principle of electromagnetic radiation in High Speed System and be: the EBG structural table reveals a kind of peculiar electromagnetic characteristic, and it is that two interplanar high-frequency currents (or noise) provide low impedance path.Two reference planes ac short circuits, this noise that just makes the generation of power supply ground level, rapidly by local low impedance path formation loop, can not outwards be propagated, thereby reaches the effect of noise suppressed.The repressed while of noise has also reduced electromagnetic radiation.
Generally, the smaller bandwidth of EBG structure and lower-cut-off frequency are very high, and the SSN frequency range of digital signal covers the high order harmonic component from DC to the clock frequency.Therefore how to reduce the lower-cut-off frequency of EBG structure or increase bandwidth and become research focus to obtain better noise suppression feature.Should weigh in addition SSN suppresses and Cost Problems.The electro-magnetic bandgap concept is incorporated in the designing and making technique of integrated circuit, utilize existing integrated circuit technology, as reactive ion body etching, based on MEMS (micro electro mechanical system) process technology of X-ray lithography technology etc., realize the combination of electro-magnetic bandgap and integrated circuit, reduce manufacture difficulty and the cost of electro-magnetic bandgap.Design a kind of novel blanketing frequency bandwidth in the present invention and reached the above compound coplanar EBG structure of 10GHz.It has realized that characteristic and the cost of manufacture of low lower limit cut-off frequency high bandwidth are low.
(3) summary of the invention
1, goal of the invention
Because the noise in the power distribution network system of electronic circuit extends in the frequency range of high frequency, hyperfrequency gradually, at present traditional interpolation decoupling capacitor and the EBG structure of existing classics can not well be applied to so high frequency range, and need to consider the problems such as the manufacture craft of electronic circuit and production cost, the invention provides a kind of electromagnetic bandgap structure and construction method thereof of optimized PCB power distribution network, it has realized the characteristic requirements that the relative band bandwidth is high, cost of manufacture is low.This compound coplanar EBG structure is compared with the EBG structure of traditional classical, has overcome the narrower shortcoming of traditional E BG STRUCTURE DEPRESSION noise band width.It is more and more wider that it can be applied in SSN noise profile scope, requires in the more and more higher high-speed signal circuit of the upper frequency limit that suppresses.This structure is by the power plane etching of two kinds of identical shaped different size shapes, and the size of effectively having dwindled electromagnetic bandgap structure, realized the miniaturization of EBG structure, is conducive to the integrated of circuit.
2, technical scheme
The electromagnetic bandgap structure of a kind of optimized PCB power distribution network of the present invention, it is a kind of compound coplanar EBG structure, this structure is periodic structure, it be by EBG construction unit (being periodic unit) along X, the Y-direction periodic extension forms.
(1) design of the construction unit of compound coplanar electromagnetic bandgap structure (EBG construction unit)
The resonance effect of compound coplanar EBG structural cycle unit itself plays a major role in the formation of band gap.As long as the cell size of periodic electromagnetism bandgap structure is more much smaller than the signal wavelength of propagating on it, the electromagnetic bandgap structure unit can be equivalent to the more intense LC resonant circuit in parallel of particular resonance characteristic, to increase the resonance performance of unit, then the infinitely-great characteristic of reactance during range site resonance, stop near the Electromagnetic Wave Propagation of resonance frequency, with the forming frequency band gap.Centre frequency and the bandwidth of band gap are determined by following formula:
Wherein, L and C are equivalent inductance and the equivalent capacity of EBG construction unit.η is the free space wave impedance, ω
0Be centre frequency, BW is relative bandwidth.Electromagnetic bandgap structure unit in the present invention consists of square metal paster and narrow bridge shape connection metal branch, as shown in Figure 1.The main corresponding equivalent capacity of square metal paster in figure, the equivalent inductance of the main corresponding EBG cellular construction of narrow bridge shape connection metal branch.Be that capacitance size is determined by the square metal paster, the inductance size is determined by narrow bridge shape connection metal branch.Therefore can change the cellular construction size, control its equivalent LC resonant circuit, thereby control bandgap center frequency and relative bandwidth.
The larger electric capacity of the area of metal patch is larger, and the longer equivalent inductance of equivalent path of narrow bridge shape connection metal branch is larger.Can be found out by formula (2), band gap width and unit equivalent capacity square root are inversely proportional to, and with unit equivalent inductance square root, are inversely proportional to.Increase electric capacity and reduce falling low-frequency band gap width that can make simultaneously, and increase inductance, increase falling low-frequency band gap width that makes simultaneously, when therefore selecting to increase inductance and reduce centre frequency, increase the bandwidth width.The coplanar EBG structure of NEW TYPE OF COMPOSITE in the present invention is exactly by taking full advantage of the unit redundancy space, increase the spatial distribution rate of narrow bridge shape connection metal branch in unit, namely increase the equivalent path of narrow bridge shape connection metal branch, realized that new E BG structure hangs down lower limit cut-off frequency high bandwidth characteristic, for realizing the EBG miniaturized structure, provide condition.
(2) parameter designing of compound coplanar electromagnetic bandgap structure
The frequency response of compound coplanar EBG structure is determined by three parameters: the lower-cut-off frequency of stopband, bandwidth of rejection, and accessible isolation in stopband.Can obtain stopband lower-cut-off frequency and the bandwidth of compound coplanar EBG structure to the dispersion map analysis of the single structure unit of compound coplanar EBG structure.Can observe by the S parameter of calculating the EBG structure stopband lower-cut-off frequency, bandwidth of rejection and the stopband isolation of compound coplanar EBG structure to the compound coplanar EBG structure that limited compound coplanar EBG construction unit forms.
The design of compound coplanar EBG structure in two steps.The first step, calculate dispersion map by the single structure unit of compound coplanar EBG structure, tentatively obtains dispersion map stopband lower-cut-off frequency and the bandwidth of rejection information of EBG structure.What dispersion map was described is electromagnetic wave wave phase constant and the curved line relation between frequency, the i.e. relation between β and f of propagating in the EBG structure.Two-dimentional compound coplanar EBG structure in the present invention, when electromagnetic wave is propagated in this structure, it can be regarded as respectively and propagate along X and Y both direction, wherein
k
x, k
yWave constant for x and y direction.
Can obviously observe the bandgap range of EBG structure from dispersion map.Do not exist electromagnetic band gap frequency range to show that electromagnetic wave can not propagate in this frequency range.Ghz area while using dispersion map can obtain to use compound coplanar EBG structure to suppress noise as isolation.The dispersion map of two dimension EBG structure solves the Brillouin zone structural theory that can adopt in the photon crystal structure theoretical system, and Brillouin zone figure corresponding to the compound coplanar EBG construction unit of two dimension as shown in Figure 3.Γ wherein, X, M is corresponding k respectively
x=k
y=0;
k
y=0;
3 points (a is EBG construction unit size).Can observe thus along X and Y two particular points of minimum and maximum wave vector on wave vector and other directions likely, can obtain enough about being with and the information of band gap by the calculating in this special section.
The present invention uses the HFSS of Finite Element simulation software to set up EBG construction unit model.Analysis obtains the two-dimension chromatic dispersion figure of compound coplanar EBG structure to cycle endless by supposing compound coplanar EBG construction unit to an EBG construction unit.For realizing that EBG construction unit cycle endless adopts principal and subordinate's boundary condition and uses the Floquet emulated port.Secondly, for the situation of analog electrical magnetic wave at infinitely great spatial, reduce the obvious reflection of truncated position, border ripple, a kind of effective ground method is that a kind of absorbing boundary condition is set in truncated position, make the ripple that is transferred to truncated position be absorbed by border and not produce reflection, thereby reach the purpose of simulation infinite space.Adopt the very outstanding PML boundary condition of a kind of absorbent properties in the present invention, it can absorb electromagnetic wave fully in limited perfect match layer, and electricity, magnetic field energy are distinguished and split in absorbing boundary, and the field component of each division is composed with different losses.The EBG cellular construction dispersion map model of setting up as shown in Figure 4.
The dispersion map that this method is applicable to the random two-dimensional electromagnetic bandgap structure solves.In the present invention, the dispersion map curve of compound coplanar EBG structure as shown in Figure 5.After calculating the dispersion map of unit, we have just known the band gap characteristic of the type electromagnetic bandgap structure that compacts.
Second step obtains the isolation of compound coplanar EBG structure by calculating the S parameter.Attainable isolation improves with the increase of the type electromagnetic bandgap structure cell number that compacts.The calculating object of S parameter is that compound coplanar EBG construction unit is expanded the EBG plane that forms for limited EBG construction unit, as shown in Figure 6.In order to calculate the S parameter, we carry out modeling and simulating with the HFSS of 3 D electromagnetic simulation software to the compound coplanar EBG structure of finite size and calculate.The simulation model of setting up as shown in Figure 7.This model be one 3 * 3 form by the EBG construction unit the two-dimentional compound coplanar EBG structure that is of a size of 90mm * 90mm.This simulation model is by bus plane, and dielectric layer and stratum form, and position annexation such as Fig. 7 between them: wherein 1 is positioned at top layer for bus plane (EBG plane layer), and 3 for stratum is positioned at bottom, and middle 2 is dielectric layers.And this bus plane is designed to compound coplanar EBG plane, and this stratum is complete metal flat, and this dielectric layer is the thick FR4 dielectric material of 0.4mm, and dielectric constant is ε
r=4.3, loss angle tangent is tan δ=0.02.In order to calculate the insertion loss of this structure, simulation calculation go out the to compact isolation degree of depth of type electromagnetic bandgap structure, add two discrete port simulation analysis in the power plane corresponding position, the rectangular coordinate initial point is positioned at the upper left side of Fig. 7, input port port1 (excitation port) and output port port2 are positioned at respectively (30mm successively, 10mm) (30mm, 50mm), application finite element software HFSS adopts 50 ohm of standard coaxial excitations.This EBG structure of emulation is in 0 transmission characteristic that arrives in the 10GHz band limits, and the simulation result that obtains as shown in Figure 8.There is obvious band gap properties in the coplanar EBG structure of NEW TYPE OF COMPOSITE that can be found out design by simulation architecture figure, when suppressing the degree of depth, be-during 30dB, bandgap range is even higher from 800MHz to 10GHz.Realized well the frequency range suppression characteristic of its low lower limit cut-off frequency high bandwidth, adapted to modem electronic circuitry PDN system noise distribution more and more wider, the more and more higher trend of the distribution frequency range upper limit.
In sum, the electromagnetic bandgap structure of a kind of optimized PCB power distribution network of the present invention, it is a kind of compound coplanar EBG structure, this structure is periodic structure, its periodic unit (being the EBG construction unit) shape is one and consists of four the narrow bridge shape of large scale connection metal branches and identical shaped eight the narrow bridge shape of small size connection metal branches and square metal paster, the connected mode of each periodic unit is to utilize the narrow bridge shape connection metal branch on each limit of periodic unit to connect, as shown in Figure 6.The shape facility of this narrow bridge shape connection metal branch is: this structure is the rectangle metal, across two EBG construction units, the square metal paster of two EBG construction units is coupled together.Electromagnetic bandgap structure Simulation Calculation in the present invention is by bus plane, and dielectric layer and stratum form, and position annexation such as Fig. 7 between them: wherein 1 is positioned at top layer for bus plane (EBG plane layer), and 3 for stratum is positioned at bottom, and middle 2 is dielectric layers.And this bus plane is designed to compound coplanar EBG plane, and this stratum is complete metal flat, and this dielectric layer is the FR4 dielectric material; The making of this compound coplanar EBG periodic structure is to utilize the circuit etching technics to carve on complete power supply metal flat, and compound coplanar EBG structural material adopts double face copper.According to different engineering application, different sizes can etch the periodic unit of corresponding varying number on power plane.As long as surpassing three at power plane structure horizontal and vertical, periodic unit quantity just can provide good inhibitory action.The EBG construction unit of emulation testing 3 * 3 in the present invention forms the EBG structure that is of a size of 90mm * 90mm., for measuring transmission loss result and simulation calculation with compound coplanar electromagnetic structure compare, add two test ports, the transmission characteristic of the coplanar EBG structure of test compound at the EBG of reality structural slab power plane same position place.The test result that obtains as shown in Figure 9.Can be found out by test curve figure, when suppressing the degree of depth, be-during 30dB, bandgap range is even higher from 800MHz to 10GHz.The bandwidth trend of test result and simulation result is substantially identical.But due to manufacture craft and spillage of material, there are nuance in simulation result and test result, but this does not affect use.
(3) construction method of the electromagnetic bandgap structure of a kind of optimized PCB power distribution network of the present invention, the method concrete steps are as follows;
Step 1: the periodic structure elementary layer of setting up the compound coplanar EBG layer of a zero thickness;
Step 2: the dielectric layer of setting up the periodic structure unit of compound coplanar EBG layer;
Step 3: set up compound coplanar EBG periodic structure unit dispersion map simulation model;
Step 4: the periodic structure unit of the compound coplanar EBG layer that step 1 is obtained is along X, and Y-direction is done periodic extension and obtained compound coplanar EBG layer;
Step 5: the dielectric layer of setting up the EBG structure.Compound coplanar EBG structure sheaf is embedded in the substrate of medium;
Step 6: add emulated port and calculate the S parameter of EBG structure;
Step 7: actual making sheet is also tested the transmission characteristic of the coplanar EBG structure of NEW TYPE OF COMPOSITE.
3, advantage and effect
1) in design process, because the bandwidth characteristic of compound coplanar EBG structure is that resonance effect by its periodic unit itself determines, the selectivity of its frequency band is directly related with the size of periodic unit itself.The periodic unit size of the compound coplanar EBG structure of so direct modification, just can revise its corresponding frequency band range, and the unit etching shape in should inventing is comparatively regular.Therefore, be convenient to the EBG construction unit is carried out Modify rapidly, accelerate the process of design.
2) this compound coplanar EBG structure has low lower limit cut-off frequency high bandwidth characteristic.Overcome the narrower shortcoming of traditional E BG STRUCTURE DEPRESSION noise band width.It is more and more wider that it can be applied in SSN noise profile scope, requires in the more and more higher high-speed signal circuit of the upper frequency limit that suppresses.
3) this compound coplanar EBG structure is by the power plane etching of two kinds of identical shaped different size shapes, and the size of effectively having dwindled electromagnetic bandgap structure, realized the miniaturization of EBG structure, is conducive to the integrated of circuit.
4) this compound coplanar EBG is simple in structure, and this structure is covered with in common upper and lower surface on the dielectric substrate of metal and just can realizes.The construction unit shape and size and the size in cycle that only need to regulate EBG structure bus plane in design process just can obtain needed performance.These structural parameters are few, greatly save the time of design optimization.
5) this EBG structure with low lower limit cut-off frequency high bandwidth is made simple and conveniently, adopts existing conventional printed circuit board manufacturing process just can realize, cost is lower.
(4) description of drawings
Fig. 1 is compound coplanar EBG construction unit layer schematic diagram in the present invention
Fig. 2 is compound coplanar EBG construction unit schematic diagram in the present invention
Fig. 3 is Brillouin zone schematic diagram corresponding to the compound coplanar EBG construction unit of two dimension in the present invention
Compound coplanar EBG construction unit dispersion map simulation model schematic diagram in Fig. 4 the present invention
Fig. 5 is the dispersion curve figure of compound coplanar EBG structure in the present invention
Fig. 6 is 3 * 3EBG floor map that in the present invention, compound coplanar EBG construction unit forms
Fig. 7 is compound coplanar EBG structure S parameters simulation model schematic diagram in the present invention
Fig. 8 is compound coplanar EBG structure S parameters simulation figure as a result in the present invention
Fig. 9 is compound coplanar EBG structure S parameter testing figure as a result in the present invention
In figure, symbol description is as follows:
1: bus plane; 2: dielectric layer; 3: stratum; Γ: k
x=k
y=0; X：
k
y=0; M：
The main boundary face of Mx:EBG cellular construction directions X; Sx:EBG cellular construction directions X from boundary face;
The main boundary face of My:EBG cellular construction Y-direction; Sy:EBG cellular construction Y-direction from boundary face;
PML: absorbing boundary condition; Port1: emulated port 1; Port: emulated port 2;
PCB: printed circuit board (PCB); PDN: power distribution network; EBG: electro-magnetic bandgap; PI: Power Integrity;
SI: signal integrity; EMI: electromagnetic radiation; SSN: mains switch noise.
(5) embodiment
The present invention is described in further detail below in conjunction with accompanying drawing.
The present invention is directed to high-speed circuit system and designed a kind of compound coplanar EBG structure with low lower limit cut-off frequency high bandwidth, it has realized the inhibition of high-speed signal circuit PDN medium-high frequency section noise.This structure increases narrow bridge shape connection metal branch path on the basis of traditional classical plane EBG structure, take full advantage of the construction unit redundant space, increase the spatial distribution rate of narrow bridge shape connection metal branch at construction unit, realize the low lower limit cut-off frequency high bandwidth characteristic of new E BG structure, for realizing the EBG miniaturized structure, provide condition.Compound coplanar EBG structure in the present invention is by one-period construction unit 3 * 3 EBG structures becoming of periodic extension in one plane.
Electromagnetic bandgap structure Simulation Calculation in the present invention is by bus plane, and dielectric layer and stratum form, and position annexation such as Fig. 7 between them: wherein 1 is positioned at top layer for bus plane (EBG plane layer), and 3 for stratum is positioned at bottom, and middle 2 is dielectric layers.And this bus plane is designed to compound coplanar EBG plane, and this stratum is complete metal flat, and this dielectric layer is the thick FR4 dielectric material of 0.4mm, and dielectric constant is ε
r=4.3, loss angle tangent is tan δ=0.02.
Described compound coplanar EBG structural plan such as Fig. 6, it is to utilize the circuit etching technics to carve on complete power supply metal flat, compound coplanar EBG structural material adopts double face copper.This structure is periodic structure, the periodic unit shape is one and consists of four the narrow bridge shape of large scale connection metal branches and identical shaped eight the narrow bridge shape of small size connection metal branches and square metal paster, the connected mode of each periodic unit is to utilize the bridge type branch on each limit of periodic unit to connect, as shown in Figure 6.According to different engineering application, different sizes can etch the periodic unit of corresponding varying number on power plane.As long as surpassing three at power plane structure horizontal and vertical, periodic unit quantity just can provide good inhibitory action.The EBG cellular construction of emulation testing 3 * 3 in the present invention forms the EBG structure that is of a size of 90mm * 90mm.Compact the type electromagnetic bandgap structure to the inhibitory action of power distribution system noise for simulation calculation and testing out, add two discrete ports in the power plane corresponding position.The rectangular coordinate initial point is positioned at the upper left side of Fig. 7, and input port port1 (excitation port) and output port port2 are positioned at respectively (30mm, 10mm) (30mm, 50mm) successively.As shown in Figure 7.Brillouin zone figure corresponding to the compound coplanar EBG construction unit of two dimension as shown in Figure 3.
The electromagnetic bandgap structure of a kind of optimized PCB power distribution network of the present invention, need to use a computer that can move based on finite element algorithm HFSS software and carry out modeling and simulation calculating.The construction method of the electromagnetic bandgap structure of a kind of optimized PCB power distribution network of the present invention, the method concrete steps are as follows:
Step 1: the periodic structure elementary layer of setting up the compound coplanar EBG layer of a zero thickness.At first use the drawing tool in the HFSS simulation software to set up a square complete plane that is of a size of 30mm * 30mm.Then use the boolean operation add-minus function in drawing tool that the cutting combination is carried out on the complete plane of square.The periodic structure unit of EBG layer is symmetrical structure, therefore also can select 1/4th sizes on the complete plane of square are operated, then apply the image feature in HFSS software, obtain the periodic structure unit of complete compound coplanar EBG layer, as shown in Figure 1.The periodic structure unit of compound coplanar EBG layer comprises the bridge type connection metal branch of two kinds of sizes.The long 8.5mm of large-sized bridge type connection metal branch wherein, wide 1.5mm, be positioned at the center of plane, EBG periodic structure unit four avris.The long 5mm of undersized bridge type connection metal branch, wide 1mm, large-sized bridge type connection metal branch is divided into four part metals sheet pieces with plane, EBG periodic structure unit, and undersized bridge type connection metal branch is positioned at the center at each sheet metal piece edge.Take full advantage of like this unit redundancy space, increase the spatial distribution rate of metal branch in unit, namely increase the equivalent path of metal branch, realized that new E BG structure hangs down lower limit cut-off frequency high bandwidth characteristic, for realizing the EBG miniaturized structure, provide condition.
Step 2: the dielectric layer of setting up the periodic structure unit of compound coplanar EBG layer.Compound coplanar EBG construction unit layer is embedded in the substrate of medium.At first make the cuboid of a 30mm * 30mm * 0.4mm with the drawing tool in the HFSS simulation software, the lower surface of cuboid end face and compound coplanar EBG periodic structure elementary layer overlaps.It is 4.3 that the cuboid material is set to dielectric constant, and magnetic permeability is 1, and loss angle tangent is 0.02.And then make the rectangle of a 30mm * 30mm with the drawing tool in HFSS software, with its stratum as compound coplanar EBG periodic structure unit.Rectangle upper surface and cuboid bottom surface overlap.So just obtain a periodic structure unit that adds the compound coplanar EBG layer of dielectric layer, as shown in Figure 2.
Step 3: set up compound coplanar EBG periodic structure unit dispersion map simulation model.Use HFSS software to set up a cuboid air shell that is of a size of 30mm * 30mm * 12mm on EBG periodic structure unit.The lower surface of cuboid overlaps with the upper surface of EBG structure sheaf in the EBG structure.Set up the PML layer on the upper surface of cuboid air shell, thereby reach the purpose of simulation infinite space, make the electromagnetic wave that is transferred to the truncated position, border be absorbed by border and not produce reflection, the thickness of PML layer is 15mm.Set up the cuboid air shell of a 30mm * 30mm * 27.4mm, its upper surface is overlapped with the upper surface of PML layer, lower surface overlaps with the stratum lower surface of EBG structure.For realizing EBG construction unit cycle endless condition, the border, four sides of model is set to principal and subordinate's boundary condition, and the simulation model of foundation as shown in Figure 4.The dispersion map simulation result that obtains as shown in Figure 5.Can find out that by the dispersion map simulation result bandgap range is distributed in 800MHz to 10GHz, even higher upper cut-off frequency.
Step 4: the periodic structure unit of the compound coplanar EBG layer that step 1 is obtained is along X, and Y-direction is done periodic extension and obtained compound coplanar EBG layer.Use the figure translation functions in the modeling of HFSS simulation software, with the periodic structure unit of the compound coplanar EBG layer that obtains in step 1 along X, Y-direction is done periodic extension, the translation distance of X and Y-direction figure is 30mm, cross spiral FSS structure sheaf after translation is 3 * 3 structural plan, as shown in Figure 6.
Step 5: the dielectric layer of setting up the EBG structure.Compound coplanar EBG structure sheaf is embedded in the substrate of medium.At first make the cuboid of a 90mm * 90mm * 0.4mm with the drawing tool in the HFSS simulation software, the lower surface of cuboid end face and compound coplanar EBG structure sheaf overlaps.It is 4.3 that the cuboid material is set to dielectric constant, and magnetic permeability is 1, and loss angle tangent is 0.02.And then make the rectangle of a 90mm * 90mm with the drawing tool in HFSS software, with its stratum as the EBG structure.Rectangle upper surface and cuboid bottom surface overlap.So just obtain a compound coplanar EBG structure of adding dielectric layer, as shown in Figure 7.
Step 6: add emulated port and calculate the S parameter of EBG structure.Compact the type electromagnetic bandgap structure to the inhibitory action of power distribution system noise for simulation calculation and testing out, use HFSS to add two discrete ports in the power plane corresponding position.The rectangular coordinate initial point is positioned at the upper left side of Fig. 6, and input port port1 (excitation port) and output port port2 are positioned at (30mm, 10mm) (30mm, 50mm) as shown in Figure 7 respectively successively.Simulation result figure as shown in Figure 8.The novel plane EBG structure that can be found out design by the S parameter has obvious band gap properties.When suppressing the degree of depth be-during 30dB, bandgap range is even higher from 800MHz to 10GHz, and is basically identical with the dispersion map simulation architecture.
Step 7: actual making sheet is also tested the transmission characteristic of the coplanar EBG structure of NEW TYPE OF COMPOSITE.According to the optimal size that step 5 is determined, processing and fabricating electromagnetic bandgap structure.Use the processes electromagnetic bandgap structure of the present invention of circuit board etching.Here select the FR4 base material, dielectric constant is 4.3, and thickness is 0.4mm, and the material upper and lower surface is copper film.Simulation model points out that the position of adding discrete port gets through hole in step 6, uses the SMA head to carry out feed, and the coaxial probe of SMA head is welded on the electromagnetic bandgap structure plane, and the earth terminal of SMA head is welded on ground plane (complete deposited copper plane).The outer conductor end face directly contacts with ground level, insertion loss is dropped to minimum.Use the Amway vector network analyzer to test, scanning frequency is set to the 0-10GHz test result and directly by the GPIB card, is read, and test result as shown in Figure 9.
Claims (2)
1. the electromagnetic bandgap structure of an optimized PCB power distribution network, it is characterized in that: it is a kind of compound coplanar EBG structure, and this structure is periodic structure, it be by the EBG construction unit along X, the Y-direction periodic extension forms;
(1) design of the construction unit of compound coplanar electromagnetic bandgap structure
The resonance effect of compound coplanar EBG structural cycle unit itself works in the formation of band gap; As long as the cell size of periodic electromagnetism bandgap structure is less than the signal wavelength of propagating on it, the electromagnetic bandgap structure unit can be equivalent to the more intense LC resonant circuit in parallel of particular resonance characteristic, to increase the resonance performance of unit, then the infinitely-great characteristic of reactance during range site resonance, stop near the Electromagnetic Wave Propagation of resonance frequency, with the forming frequency band gap; Centre frequency and the bandwidth of band gap are determined by following formula:
Wherein, L and C are equivalent inductance and the equivalent capacity of EBG construction unit; η is the free space wave impedance, ω
0Be centre frequency, BW is relative bandwidth; The electromagnetic bandgap structure unit consists of square metal paster and narrow bridge shape connection metal branch; The corresponding equivalent capacity of square metal paster, the equivalent inductance of the corresponding EBG cellular construction of narrow bridge shape connection metal branch; Be that capacitance size is determined by the square metal paster, the inductance size is determined by narrow bridge shape connection metal branch; Therefore change the cellular construction size, control its equivalent LC resonant circuit, thereby control bandgap center frequency and relative bandwidth;
The larger electric capacity of the area of metal patch is larger, and the longer equivalent inductance of equivalent path of narrow bridge shape connection metal branch is larger; Found out by formula (2), band gap width and unit equivalent capacity square root are inversely proportional to, and with unit equivalent inductance square root, are inversely proportional to; Increase electric capacity and reduce falling low-frequency band gap width that can make simultaneously, and increase inductance, increase falling low-frequency band gap width that makes simultaneously, when therefore selecting to increase inductance and reduce centre frequency, increase the bandwidth width; The EBG structure is exactly by taking full advantage of the unit redundancy space, increase the spatial distribution rate of narrow bridge shape connection metal branch in unit, namely increase the equivalent path of narrow bridge shape connection metal branch, realized that the EBG structure hangs down lower limit cut-off frequency high bandwidth characteristic, for realizing the EBG miniaturized structure, provide condition;
(2) parameter designing of compound coplanar electromagnetic bandgap structure
The frequency response of compound coplanar EBG structure is determined by three parameters: the lower-cut-off frequency of stopband, bandwidth of rejection, and the isolation that reaches in stopband; The dispersion map analysis of the single structure unit of compound coplanar EBG structure is obtained stopband lower-cut-off frequency and the bandwidth of compound coplanar EBG structure; The compound coplanar EBG structure that limited compound coplanar EBG construction unit forms is observed the stopband lower-cut-off frequency of compound coplanar EBG structure, bandwidth of rejection and stopband isolation by the S parameter of calculating the EBG structure;
The design of compound coplanar EBG structure in two steps;
The first step, calculate dispersion map by the single structure unit of compound coplanar EBG structure, tentatively obtains dispersion map stopband lower-cut-off frequency and the bandwidth of rejection information of EBG structure; What dispersion map was described is electromagnetic wave wave phase constant and the curved line relation between frequency, the i.e. relation between β and f of propagating in the EBG structure; Concerning the compound coplanar EBG structure of two dimension, when electromagnetic wave is propagated in this structure, it is regarded as respectively and propagates along X and Y both direction, wherein
k
x, k
yWave constant for x and y direction;
Obviously observe the bandgap range of EBG structure from dispersion map; Do not exist electromagnetic band gap frequency range to show that electromagnetic wave can not propagate in this frequency range; Ghz area while using dispersion map to obtain to use compound coplanar EBG structure to suppress noise as isolation; The dispersion map of two dimension EBG structure solves the Brillouin zone structural theory that adopts in the photon crystal structure theoretical system;
Use the HFSS of Finite Element simulation software to set up EBG construction unit model; Analysis obtains the two-dimension chromatic dispersion figure of compound coplanar EBG structure to cycle endless by supposing compound coplanar EBG construction unit to an EBG construction unit; For realizing that EBG construction unit cycle endless adopts principal and subordinate's boundary condition and uses the Floquet emulated port; Secondly, for the situation of analog electrical magnetic wave at infinitely great spatial, reduce the obvious reflection of truncated position, border ripple, a kind of effective ground method is that a kind of absorbing boundary condition is set in truncated position, make the ripple that is transferred to truncated position be absorbed by border and not produce reflection, thereby reach the purpose of simulation infinite space; Adopt the very outstanding PML boundary condition of a kind of absorbent properties, it can absorb electromagnetic wave fully in limited perfect match layer, and electricity, magnetic field energy are distinguished and split in absorbing boundary, and the field component of each division is composed with different losses;
Second step obtains the isolation of compound coplanar EBG structure by calculating the S parameter; The isolation of realizing improves with the increase of the type electromagnetic bandgap structure cell number that compacts; The calculating object of S parameter is that compound coplanar EBG construction unit is expanded the EBG plane that forms for limited EBG construction unit,, in order to calculate the S parameter, utilize the HFSS of 3 D electromagnetic simulation software to carry out modeling and simulating to the compound coplanar EBG structure of finite size and calculate; The simulation model of setting up, this model be one 3 * 3 form by the EBG construction unit the two-dimentional compound coplanar EBG structure that is of a size of 90mm * 90mm; This simulation model is by bus plane, and dielectric layer and stratum form, and wherein 1 for bus plane is positioned at top layer, and 3 for stratum is positioned at bottom, and middle 2 is dielectric layers; And this bus plane is designed to compound coplanar EBG plane, and this stratum is complete metal flat, and this dielectric layer is the thick FR4 dielectric material of 0.4mm, and dielectric constant is ε
r=4.3, loss angle tangent is tan δ=0.02; In order to calculate the insertion loss of this structure, simulation calculation go out the to compact isolation degree of depth of type electromagnetic bandgap structure, add two discrete port simulation analysis in the power plane corresponding position, input port port1(excitation port) and output port port2 be positioned at successively respectively (30mm, 10mm) (30mm, 50mm), application finite element software HFSS adopts 50 ohm of standard coaxial excitations; This EBG structure of emulation is in 0 transmission characteristic that arrives in the 10GHz band limits; There is obvious band gap properties in the coplanar EBG structure of NEW TYPE OF COMPOSITE of being found out design by simulation architecture figure, when suppressing the degree of depth, be-during 30dB, bandgap range is even higher from 800MHz to 10GHz; Realized the frequency range suppression characteristic of its low lower limit cut-off frequency high bandwidth, adapted to modem electronic circuitry PDN system noise distribution more and more wider, the more and more higher trend of the distribution frequency range upper limit.
2. the construction method of the electromagnetic bandgap structure of an optimized PCB power distribution network, the method concrete steps are as follows:
Step 1: the periodic structure elementary layer of setting up the compound coplanar EBG layer of a zero thickness; At first use the drawing tool in the HFSS simulation software to set up a square complete plane that is of a size of 30mm * 30mm; Then use the boolean operation add-minus function in drawing tool that the cutting combination is carried out on the complete plane of square; The periodic structure unit of EBG layer is symmetrical structure, therefore also can select 1/4th sizes on the complete plane of square are operated, and then applies the image feature in HFSS software, obtains the periodic structure unit of complete compound coplanar EBG layer; The periodic structure unit of compound coplanar EBG layer comprises the bridge type connection metal branch of two kinds of sizes; The long 8.5mm of large-sized bridge type connection metal branch wherein, wide 1.5mm, be positioned at the center of plane, EBG periodic structure unit four avris; The long 5mm of undersized bridge type connection metal branch, wide 1mm, large-sized bridge type connection metal branch is divided into four part metals sheet pieces with plane, EBG periodic structure unit, and undersized bridge type connection metal branch is positioned at the center at each sheet metal piece edge; The range site redundant space, increase the spatial distribution rate of metal branch in unit, namely increases the equivalent path of metal branch, realized that the EBG structure hangs down lower limit cut-off frequency high bandwidth characteristic, for realizing the EBG miniaturized structure, provides condition;
Step 2: the dielectric layer of setting up the periodic structure unit of compound coplanar EBG layer; Compound coplanar EBG construction unit layer is embedded in the substrate of medium; At first make the cuboid of a 30mm * 30mm * 0.4mm with the drawing tool in the HFSS simulation software, the lower surface of cuboid end face and compound coplanar EBG periodic structure elementary layer overlaps; It is 4.3 that the cuboid material is set to dielectric constant, and magnetic permeability is 1, and loss angle tangent is 0.02; And then make the rectangle of a 30mm * 30mm with the drawing tool in HFSS software, with its stratum as compound coplanar EBG periodic structure unit; Rectangle upper surface and cuboid bottom surface overlap; Obtain a periodic structure unit that adds the compound coplanar EBG layer of dielectric layer;
Step 3: set up compound coplanar EBG periodic structure unit dispersion map simulation model; Use HFSS software to set up a cuboid air shell that is of a size of 30mm * 30mm * 12mm on EBG periodic structure unit; The lower surface of cuboid overlaps with the upper surface of EBG structure sheaf in the EBG structure; Set up the PML layer on the upper surface of cuboid air shell, thereby reach the purpose of simulation infinite space, make the electromagnetic wave that is transferred to the truncated position, border be absorbed by border and not produce reflection, the thickness of PML layer is 15mm; Set up the cuboid air shell of a 30mm * 30mm * 27.4mm, its upper surface is overlapped with the upper surface of PML layer, lower surface overlaps with the stratum lower surface of EBG structure; For realizing EBG construction unit cycle endless condition, the border, four sides of model is set to principal and subordinate's boundary condition, the simulation model of foundation; The dispersion map simulation result that obtains; Can find out that by the dispersion map simulation result bandgap range is distributed in 800MHz to 10GHz, even higher upper cut-off frequency;
Step 4: the periodic structure unit of the compound coplanar EBG layer that step 1 is obtained is along X, and Y-direction is done periodic extension and obtained compound coplanar EBG layer; Use the figure translation functions in the modeling of HFSS simulation software, with the periodic structure unit of the compound coplanar EBG layer that obtains in step 1 along X, Y-direction is done periodic extension, and the translation distance of X and Y-direction figure is 30mm, and the cross spiral FSS structure sheaf after translation is 3 * 3 structural plan;
Step 5: the dielectric layer of setting up the EBG structure; Compound coplanar EBG structure sheaf is embedded in the substrate of medium; At first make the cuboid of a 90mm * 90mm * 0.4mm with the drawing tool in the HFSS simulation software, the lower surface of cuboid end face and compound coplanar EBG structure sheaf overlaps; It is 4.3 that the cuboid material is set to dielectric constant, and magnetic permeability is 1, and loss angle tangent is 0.02; And then make the rectangle of a 90mm * 90mm with the drawing tool in HFSS software, with its stratum as the EBG structure; Rectangle upper surface and cuboid bottom surface overlap; Obtain a compound coplanar EBG structure of adding dielectric layer;
Step 6: add emulated port and calculate the S parameter of EBG structure; Compact the type electromagnetic bandgap structure to the inhibitory action of power distribution system noise for simulation calculation and testing out, use HFSS to add two discrete ports in the power plane corresponding position; The EBG structure of being found out design by the S parameter has obvious band gap properties; When suppressing the degree of depth be-during 30dB, bandgap range is even higher from 800MHz to 10GHz, and is consistent with the dispersion map simulation architecture;
Step 7: actual making sheet is also tested the transmission characteristic of the coplanar EBG structure of NEW TYPE OF COMPOSITE; According to the optimal size that step 5 is determined, processing and fabricating electromagnetic bandgap structure; Use the processes electromagnetic bandgap structure of circuit board etching; Select the FR4 base material, dielectric constant is 4.3, and thickness is 0.4mm, and the material upper and lower surface is copper film; Simulation model points out that the position of adding discrete port gets through hole in step 6, uses the SMA head to carry out feed, and the coaxial probe of SMA head is welded on the electromagnetic bandgap structure plane, and the earth terminal of SMA head is welded on ground plane; The outer conductor end face directly contacts with ground level, insertion loss is dropped to minimum; Use the Amway vector network analyzer to test, scanning frequency is set to the 0-10GHz test result and directly by the GPIB card, is read.
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| CN103683904A (en) * | 2013-12-09 | 2014-03-26 | 上海交通大学 | Power source distribution network with small electromagnetic band gap structure units |
| JP6540610B2 (en) * | 2016-06-13 | 2019-07-10 | 株式会社村田製作所 | Transmission characteristic measuring method and transmission characteristic measuring apparatus |
| CN106645909B (en) * | 2016-12-20 | 2019-03-29 | 中国电子科技集团公司第五十四研究所 | Power supply rejection device based on embedded capacitance substrate |
| CN107135606B (en) * | 2017-06-09 | 2019-09-27 | 郑州云海信息技术有限公司 | A method of improving PCB Power Integrity using full cavity model |
| CN107256309A (en) * | 2017-06-09 | 2017-10-17 | 郑州云海信息技术有限公司 | A kind of SI, PI and EMC collaborative design method of high performance PCB |
| CN107301290B (en) * | 2017-06-20 | 2020-07-10 | 西安交通大学 | Power distribution network growth type topology optimization method of electromagnetic band gap power panel |
| CN107402383B (en) * | 2017-09-11 | 2019-03-26 | 重庆邮电大学 | A kind of bi-phase modulated plate and method for implementing radar frequency spectrum shift |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US20100156523A1 (en) * | 2008-12-23 | 2010-06-24 | Jong Hwa Kwon | Arrangement structure of electromagnetic band-gap for suppressing noise and improving signal integrity |
| CN102033976A (en) * | 2010-09-17 | 2011-04-27 | 北京航空航天大学 | Compact electromagnetic band gap structure for avoiding high-speed circuit noise |
-
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
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| US20100156523A1 (en) * | 2008-12-23 | 2010-06-24 | Jong Hwa Kwon | Arrangement structure of electromagnetic band-gap for suppressing noise and improving signal integrity |
| CN102033976A (en) * | 2010-09-17 | 2011-04-27 | 北京航空航天大学 | Compact electromagnetic band gap structure for avoiding high-speed circuit noise |
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