CN203423483U - Non-grounded antenna-feed anti-surge device used for node of wireless sensor. - Google Patents

Abstract

The utility model discloses a non-grounded antenna-feed anti-surge device used for a node of a wireless sensor. The non-grounded antenna-feed anti-surge device includes an antenna connecting port and a node connecting port, wherein a three-level parallel circuit is connected between the two ports. The three-level parallel circuit is composed of a GDT (Gas Discharge Tube), a piezoresistor Rv, and a TVS (Transient Voltage Suppressor). The different levels are connected through inductors, so as to achieve a decoupling effect. The length of the central signal line 3 is lambda/2. A capacitor C1 in connection prevents low-frequency transient excess current from entering the to-be-protected circuit. Both sides of a PCB are provided with no wiring area and the PCB is in array connection through via holes and serves as a current discharging zone. The line width of a branch of the GDT is 3.81 mm and the line width of a cross connection wire of a grounding welding pad and the discharging zone is 1.9 mm, so that current discharging capacity is enhanced. The non-grounded antenna-feed anti-surge device is advantageous in that: no grounding is needed and surge energy can be absorbed quickly; the non-grounded antenna-feed anti-surge device has low residual voltage and large discharge current capacity; the non-grounded antenna-feed anti-surge device is capable of protecting network nodes, which have low voltage-withstanding capacity and low current-withstanding capacity, of the wireless sensor effectively; and the non-grounded antenna-feed anti-surge device can be applied to antenna-feed port surge resistance in a non-grounded condition.

Description

A kind of wireless sensor node is without ground connection antenna feeder Anti-surging device

Technical field

The utility model belongs to technical field of wireless, is specifically related to the Anti-surging technology of wireless sensor node.

Background technology

The wireless sensor network node that is deployed in field is spacious because of environment, and periphery covers without pile and lightning rod, is subject to thunder and lightning and surge and attacks and cause damage.Compare with direct lightning strike, surge enters that the probability of happening that antenna port causes that node transceiver module lost efficacy is high, influence area is vast, need to increase the antisurge performance that anti-surge circuit improves node.

Existing wireless sensor network antenna feeder Anti-surging device mostly is the coaxial resonant cavity of the earthing of casing ^[1-3], interior deployment single-stage ^[1]or plural parallel stage ^[2]air discharge tube, and λ/4 short branch ^[3]deng greatly, get around regulations discharge device, will transfinite charge inducing and current drain enter ground.The requirement of this protection Design to good earth, significantly reduced and take the cost performance of the wireless sensor network that low cost is one of principal character, the regular maintenance that particularly ground connection needs, the network remote to being arranged in, personnel are difficult to arrival area does not almost have feasibility.

The existing earth-free antenna feeder Anti-surging design being applied on GPS ^[4], in antenna interface circuit, set up the two-stage II type circuit being formed by piezo-resistance, the amount of getting around regulations is little, and barrier propterty is poor.The utility model is that the wireless sensor network node of common 2.4GHz frequency range is (as serial in the JN51 of Jennic company; the CC2430 of TI company 2530) design surge protective device; directly on pcb board, by air discharge tube, piezo-resistance and Transient Voltage Suppressor TVS, manage three grades of parallel circuitss; the amount of getting around regulations is large, output residual voltage is low; can effectively suppress temporary overvoltage, shunting surge current, reach the requirement to the amount of getting around regulations and Anti-surging immunity to interference in national standard ^[4,5].Realized the protection to the wireless sensor network node of low withstand voltage, low resistance to stream, echo and insertion loss are low, do not affect signal normal transmission.

Wireless sensor node antenna port is subject to the surge attack that thunder and lightning causes, need to have protection circuit.But existing coaxial-type antenna feeder Anti-surging device is to the strict demand of ground connection and higher cost, can not be applicable to low cost, non-maintaining wireless sensor network; The existing earth-free anti-surge circuit amount of getting around regulations is little, and barrier propterty does not reach standard; Wireless sensor network node transceiver module operating frequency is high, transmitting power is little, withstand voltage, flow-resistant capacity is poor, requires surge protection circuit can be operated in high-frequency; output residual voltage is low, and the amount of getting around regulations is large, and shock-resistant voltage is high; echo and insertion loss are low, little on the impact of communication.

Documents

[1] Phoenix Asia-Pacific electrical equipment (Nanjing) Co., Ltd, Xu Zhuqin, Gao Xuanhui, appoints the Huashan. antenna feeder lightning-proof device utility model patent Granted publication CN201594584U, Granted publication day 2010.09.29 application number 200920282857.1

[2] .DKBA1268-2003.08 of Huawei Tech Co., Ltd protection circuit design specification

[3] Amphenol CNT (Xi'an) Technology Ltd., Hu Bo. a kind of adjustment method of 1/4 λ antenna feeder arrester, utility model patent publication number CN101350438A, open day 2009.1.21

[4] Zhang Lei, Cui Jianbao. a kind of GPS active antenna interface antisurging shock device. utility model patent Granted publication CN2790007Y, Granted publication day 2006.6.21

[5] People's Republic of China's house and town and country construction Bu， State Administration for Quality Supervision and Inspection and Quarantine. the lightning protection and grounding engineering design standard GB50689-2011.2011-04-02 of communication bureau's (station) issue, 2012-05-01 implements

[6] General Administration of Quality Supervision, Inspection and Quarantine o of the People's Republic of China, Standardization Administration of China. EMC test and measuring technique surge (impact) immunity experiment GB/T17626.5-2008.2008-05-20 issue, 2009-01-01 implements

Utility model content

The purpose of this utility model is to provide a kind of wireless sensor node without ground connection antenna feeder Anti-surging device, reach the antenna feeder Anti-surging object without ground connection, improve antenna port Anti-surging grade, keep low-cost, the non-maintaining feature of wireless sensor network, realize without the Anti-surging under grounding requirement.

In order to solve above technical problem, the concrete technical scheme that the utility model adopts is as follows:

Without a ground connection antenna feeder Anti-surging device, comprise by with capacitor C ₁connected antenna connection terminal mouth and the node connectivity port of center signal line, and by air discharge tube GDT, piezo-resistance R _v, Transient Voltage Suppressor TVS and inductance L ₁～L ₄three grades of parallel circuitss that form, is characterized in that in described three grades of parallel circuitss:

Inductance L is passed through in one end of air discharge tube GDT ₁be connected with antenna connection terminal mouth, pass through inductance L simultaneously ₂with piezo-resistance R _vbe connected, the other end ground connection of air discharge tube GDT; Inductance L is passed through in one end of Transient Voltage Suppressor TVS ₄be connected with node connectivity port, pass through inductance L simultaneously ₃with piezo-resistance R _vbe connected, the other end ground connection of Transient Voltage Suppressor TVS; Piezo-resistance R _vone end connects inductance L ₂and inductance L ₃, other end ground connection; Inductance L ₂and inductance L ₃for other inductance of microhenry level;

Described circuit is directly realized on pcb board; Pcb board two sides without cabling region, cover copper, by arrays of vias, be connected as flood discharge ground, antenna connection terminal mouth, air discharge tube GDT, piezo-resistance R _vwith the earth terminal of Transient Voltage Suppressor TVS by ground pad and flood discharge be connected, the first order air discharge tube branch road printed circuit board line width consisting of air discharge tube GDT is more than or equal to 3.81mm.

Described center signal line length is λ/2, and λ is transmitted signal wavelengths.

Described inductance L ₂and inductance L ₃be connected to and between two-stage, play decoupling effect.

Described capacitor C ₁resistance to pressure is more than or equal to the voltage of Anti-surging class requirement.

Described air discharge tube GDT, piezo-resistance R _vadopt cross line and flood discharge with the ground pad of Transient Voltage Suppressor TVS and be connected, cross line live width is more than or equal to 1.9mm.

The impedance matching of described device and antenna and node; The equiva lent impedance of described antenna and node is 50 ohm.

The utlity model has beneficial effect.

(1) the utility model has improved antenna port Anti-surging grade without the antenna feeder Anti-surging device of ground connection, has kept low-cost, the non-maintaining feature of wireless sensor network;

(2) three grades of parallel circuitss that formed by air discharge tube, piezo-resistance and Transient Voltage Suppressor TVS in the utility model, discharge, only by piezo-resistance, compare with λ/4 anti-surge circuit with independent air hose, residual voltage is low, the amount of getting around regulations is large, starting resistor is low, frequency band is narrow, fast response time, can carry out effectively protection to low wireless sensor network node sensitive chip withstand voltage, low resistance to stream;

(3) λ/2 center signal line length that the utility model adopts and the design of prevention high frequency bypass, make Anti-surging device low in 2.4GHz frequency range return loss, and insertion loss is little;

(4) the utility model can be applied having under good earth condition equally, and Anti-surging effect is better;

(5) the utility model can, from 2.4GHz wireless sensor node, be applied to the carrying out surge protection of other communications band.

Accompanying drawing explanation

Fig. 1. each parts connection diagram of antenna feeder Anti-surging device;

Fig. 2. anti-surge circuit impedance matching isoboles;

Fig. 3. Anti-surging device return loss plot figure.

In figure: 1, antenna connection terminal mouth 2, node connectivity port 3, center signal line 4, arrays of vias 5, flood discharge ground 6, air discharge tube branch road 7, pcb board.

Embodiment

For further explaining the purpose of this utility model, technical scheme and beneficial effect, take that being operated in the CC2530 node that 2.4GH frequency range, operating voltage are 2～3.6V is that example describes in detail.The antenna port Anti-surging device that the utility model relates to comprises that the impedance matching of three grades of parallel circuitss, device and nodes and antenna and pcb board make three parts.

1. 2.4GHz antenna feeder Anti-surging device described in the utility model is usingd CC2530 node and is designed as protected node, requires surge protection circuit can be operated in high-frequency, and output residual voltage is low, and the amount of getting around regulations is large, the characteristic that shock-resistant voltage is high.Three grades of surge protection circuits of design, as shown in Figure 1.

(1) the 1st grade of air discharge tube GDT: the standard amount of getting around regulations of the lightning protection and grounding engineering design standard > > of GB GB50689-2011 < < communication bureau (station) regulation Antenna System SPD (SurgeProtectionDevice) is >=10kA, to select discharge capacity be 20kA to air discharge tube GDT herein.The DC breakdown voltage of air discharge tube GDT should meet: U _s>=1.8U _p, U in formula _sfor DC breakdown voltage, U _pfor the voltage peak of the normal operation of circuit, by protected node operating voltage U _pbe 2～3.6V, obtain U _s>=6.5V; While U _sshould be less than the highest withstand voltage U of second class protection element piezo-resistance _rm, U herein _rmfor 165V.In sum, air discharge tube GDT selects the A81-C90X of EPCOS company, U _sfor 90V, maximum through-current capacity 20kA, parasitic capacitance is less than 1.5pf, and insulation resistance is greater than 10G Ω.Conducting when air discharge tube GDT exists overvoltage in heart yearn, both end voltage maintains 50V, and residual voltage is higher, and the 2nd grade of piezo-resistance Rv and Transient Voltage Suppressor TVS composition is further reduced output residual voltage with 3rd level protection circuit.

The 2nd grade of piezo-resistance R _v: the response time is less than air discharge tube GDT, damages 3 grades of circuit while avoiding air discharge tube not move.Piezo-resistance R _vpressure sensitive voltage U _rshould have: U _r>=(1.2～1.5) U _p, by protected node operating voltage U _pbe that 2～3.6V obtains U _r>=5.4V.Piezo-resistance R _vthe amount of getting around regulations requires as kA level, and piezo-resistance is selected 20D180K type herein, and the amount of getting around regulations is 2kA, and pressure sensitive voltage is 18V.

3rd level Transient Voltage Suppressor TVS can clamp the voltage at node operating voltage, and the response time is rapid, can play in final stage the effect of meticulous protection.Because this passage does not have the air discharge tube GDT branch road amount of getting around regulations large, therefore shock-resistant voltage request is not high.The reverse breakdown voltage U of Transient Voltage Suppressor TVS _bRshould there is U _bR>=(1.3～1.6) U _p, U _pbe that voltage peak in loop is 3.6V, Transient Voltage Suppressor TVS puncture voltage should be greater than 3.6 * 1.6=5.76V.Due to CC2530 transmission be high frequency ac signal, Transient Voltage Suppressor TVS should select ambipolar.Transient Voltage Suppressor TVS selects ESD5B5.0ST1G herein, is bipolarity TVS pipe, and discharge capacity reaches 30A, and reverse breakdown voltage is 5.8～7.8V, and clamp voltage is 5V, and parasitic capacitance is 32pf.

(2) center signal line 3 is signal transmssion lines that antenna connection terminal mouth 1 arrives between node connectivity port 2, passes through high-frequency signal during normal operation.Be associated in the capacitor C on center signal line 3 ₁: value should be consistent with electric capacity on holding wire in CC2530 node radio frequency matching circuit, is all pf level; The instantaneous thousands of volt high pressure that produced by thunder and lightning, require capacitor C ₁resistance to pressure is strong, therefore selects CB(polystyrene electric capacity) high pressure resistant series, resistance to direct voltage is 3kV.When circuit production, with 2.2nf, 5pf, 6.8nf, 15pf, 33pf, 100pf, to test respectively, result is 5pf electric capacity to the transmission range of the node minimum that exerts an influence.C1 finally elects 3kV5pfCB electric capacity as.

(3) inductance L of connecting with air discharge tube ₁, prevent high-frequency signal bypass, in direct current and low-frequency range, by heart yearn and discharge tube short circuit.Air discharge tube GDT conducting during thunderbolt, the overvoltage/overcurrent of center line will be effectively suppressed.Due to L ₁be the path of releasing of overcurrent, so discharge capacity should meet design objective, the surge current of tolerance 10kA.

(4) inductance L between protection device ₂, L ₃play decoupling, while avoiding being struck by lightning, Transient Voltage Suppressor TVS damages prior to gas discharge tube prior to piezo-resistance and piezo-resistance, generally gets large capacity μ H level.Select 100 μ H iron inductances to play decoupling effect herein.For high-frequency signal, be equivalent to open circuit herein; For direct current and low frequency signal, from then on the electric current that transfinites can pass through.

The surge causing when thunder and lightning etc. arrives, and when surge voltage is greater than Transient Voltage Suppressor TVS puncture voltage (5.8～7.8V), first Transient Voltage Suppressor TVS starts, and transient overvoltage is accurately controlled to 5V left and right; If surge current is large, piezo-resistance starting, and certain surge current of releasing; Surge voltage continues to increase, and the voltage at piezo-resistance two ends can increase, until promote the electric discharge of prime gas discharge tube during 90V left and right, large current drain to the flood discharge ground on PCB circuit board.

2. the impedance matching between device and node and antenna.

L in Fig. 1 ₂and L ₃get large inductance, at 2.4GHz high band, be equivalent to open circuit, air discharge tube GDT and Transient Voltage Suppressor TVS have parasitic capacitance at high band, so Fig. 1 can equivalence become Fig. 2.C ₂for the parasitic capacitance of air discharge tube GDT, C ₃parasitic capacitance for Transient Voltage Suppressor TVS.Z ₁for antenna connection terminal image impedance, Z ₂for node link image impedance.Image impedance Z ₁computing formula be:

$Z_1=\sqrt{Z_{\mathrm{oc}1}{Z}_{\mathrm{sc}1}}---\left(1\right)$

Wherein, Z _oc1and Z _sc1the antenna connection terminal mouth input impedance of circuit while being respectively node connectivity port open circuit and short circuit.

According to Fig. 2, have,

$Z_{\mathrm{<figure-callout\; id="1"\; label="oc"\; filenames="DEST\_PATH\_131206110952.png,DEST\_PATH\_131206110956.png"\; state="\{\{state\}\}">oc</figure-callout>}1}=({\mathrm{j\&omega;<figure-callout\; id="1"\; label="L"\; filenames="DEST\_PATH\_131206110952.png,DEST\_PATH\_131206110956.png"\; state="\{\{state\}\}">L</figure-callout>}}_1+\frac{1}{{\mathrm{j\&omega;C}}_2})//(\frac{1}{{\mathrm{j\&omega;<figure-callout\; id="1"\; label="C"\; filenames="DEST\_PATH\_131206110952.png,DEST\_PATH\_131206110956.png"\; state="\{\{state\}\}">C</figure-callout>}}_1}+{\mathrm{j\&omega;<figure-callout\; id="4"\; label="L"\; filenames="DEST\_PATH\_131206110948.png"\; state="\{\{state\}\}">L</figure-callout>}}_4+\frac{1}{{\mathrm{j\&omega;C}}_3})---\left(2\right)$

$Z_{\mathrm{<figure-callout\; id="1"\; label="sc"\; filenames="DEST\_PATH\_131206110952.png,DEST\_PATH\_131206110956.png"\; state="\{\{state\}\}">sc</figure-callout>}1}=({\mathrm{j\&omega;<figure-callout\; id="1"\; label="L"\; filenames="DEST\_PATH\_131206110952.png,DEST\_PATH\_131206110956.png"\; state="\{\{state\}\}">L</figure-callout>}}_1+\frac{1}{{\mathrm{j\&omega;C}}_2})//\left(\frac{1}{{\mathrm{j\&omega;C}}_1}\right)---\left(3\right)$

Image impedance Z ₂computing formula be:

${\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="DEST\_PATH\_131206110948.png,DEST\_PATH\_131206110952.png"\; state="\{\{state\}\}">Z</figure-callout>}}_2=\sqrt{Z_{\mathrm{oc}2}{Z}_{\mathrm{sc}2}}---\left(4\right)$

Wherein, Z _oc2and Z _sc2the node connectivity port input impedance of circuit while being respectively antenna connection terminal mouth open circuit and short circuit.

According to Fig. 2, have,

${\mathrm{<figure-callout\; id="2"\; label="Z\; oc"\; filenames="DEST\_PATH\_131206110948.png,DEST\_PATH\_131206110952.png"\; state="\{\{state\}\}">Z</figure-callout>}}_{\mathrm{oc}}=({\mathrm{j\&omega;<figure-callout\; id="4"\; label="L"\; filenames="DEST\_PATH\_131206110948.png"\; state="\{\{state\}\}">L</figure-callout>}}_4+\frac{1}{{\mathrm{j\&omega;C}}_3})//(\frac{1}{{\mathrm{j\&omega;<figure-callout\; id="1"\; label="C"\; filenames="DEST\_PATH\_131206110952.png,DEST\_PATH\_131206110956.png"\; state="\{\{state\}\}">C</figure-callout>}}_1}+{\mathrm{j\&omega;<figure-callout\; id="1"\; label="L"\; filenames="DEST\_PATH\_131206110952.png,DEST\_PATH\_131206110956.png"\; state="\{\{state\}\}">L</figure-callout>}}_1+\frac{1}{{\mathrm{j\&omega;C}}_2})---\left(5\right)$

${\mathrm{<figure-callout\; id="2"\; label="Z\; sc"\; filenames="DEST\_PATH\_131206110948.png,DEST\_PATH\_131206110952.png"\; state="\{\{state\}\}">Z</figure-callout>}}_{\mathrm{sc}}=({\mathrm{j\&omega;<figure-callout\; id="4"\; label="L"\; filenames="DEST\_PATH\_131206110948.png"\; state="\{\{state\}\}">L</figure-callout>}}_4+\frac{1}{{\mathrm{j\&omega;C}}_3})//\left(\frac{1}{{\mathrm{j\&omega;C}}_1}\right)---\left(6\right)$

After the model of selected air discharge tube GDT and Transient Voltage Suppressor TVS, C ₂and C ₃known, C ₁should get the same order of magnitude with electric capacity in intra-node radio frequency matching circuit, ω=2 π * 2.4GHz, can obtain L by formula (1) and formula (4) ₁and L ₄.This two-port network all forms and mates with front and back stages.

In Fig. 2, C ₂for the parasitic capacitance of air discharge tube GDT, be worth for 1.5pf; C ₃for the parasitic capacitance of Transient Voltage Suppressor TVS, be worth for 32pf.For the two-port network shown in Fig. 2, Z ₁for antenna connection terminal image impedance, should equal antenna impedance 50 Ω; Z ₂for node link image impedance, should equal node equivalent impedance 50 Ω.C ₁=5pf, C ₂=1.5pf, C ₃=32pf, ω=2 π * 2.4GHz brings formula (1)～(6) into can calculate to obtain L ₄≈ 5.4nH, L ₁≈ 151nH.

During actual fabrication circuit, except the lumped parameter of element, the distributed constant of circuit and element can not be ignored, and needs with measuring, parameter to be adjusted by experiment.

3.PCB plate

(1) according to λ/2 impedance repeatability character, the impedance phase at a distance of place, λ/2 on transmission line is same.Therefore Fig. 1 center signal line 3 length are taken as signal wavelength half.CC2530 operating frequency is 2.4GHz, and wavelength is 12.5cm, and half-wavelength is 6.25cm, and at actual Zuo Banshidui center, holding wire 3 length are finely tuned.

(2), while carrying out wiring, print cabling and will consider that power capacity can not be too thin, particularly flood discharge circuit.The general cabling on printed board top layer, the about 1kA of 8/20us impulse current that 15mil live width can be born, wherein 1mil=0.00254cm so air discharge tube branch road 6 live width selection >=Anti-surging rank * 15*0.0254mm.Because antenna port requires Anti-surging rank >=10kA, so live width is selected 3.81mm.

Cross connecting line between element ground pad and flood discharge ground is defaulted as 0.254mm, and line is too thin, after change 1.9mm into.

(3) air discharge tube 7 is placed near antenna connection terminal mouth 1, and the line of discharge tube and signal center's holding wire 3 and short as far as possible to the line on ground, is beneficial to overcurrent and from discharge tube, releases fast.The PCB line of discharge tube place path should lack via hole as far as possible, and live width will be consistent.

(4) Anti-surging device is operated in 2.4GHz radio band, for avoiding interference, near center signal line 3, can not have ground.In Fig. 1, around cover copper hollows out processing to center signal line 3.

(5) what pcb board size was done is slightly large, and upper strata components and parts around vacant place are done large area and covered copper, by a large amount of arrays of vias 4, are connected with PCB stratum, increase the area on ground, as the flood discharge of large electric current 5.

4. test result

Finally this mount board is carried out to many-side test, result is as follows:

(1) communication distance

At node, add after antenna feeder Anti-surging device, actual measurement maximum communication distance ratio does not reduce 15% while not adding Anti-surging device.

(2) return loss

With vector network analyzer, antenna feeder Anti-surging device is measured, obtained center frequency point at 2.43GHz, the following bandwidth of-10dB is 2.38～2.50GHz, and the return loss of center frequency point is-20.9dB that return loss plot figure as shown in Figure 3.

(3) packet loss

Add after Anti-surging device, in proper communication distance, as 50% of maximum communication distance, allow two nodes carry out data communication, packet loss does not change.

5. Anti-surging level estimate

Experiment condition and technical standard according to GB GB/T17626.5-2008 < < EMC test and measuring technique surge (impact) immunity experiment > > standard code are carried out Anti-surging level estimate to the utility model.

1) surge waveform: composite wave, is 1.2/50 μ s surge voltage ripple, 8/20 μ s impulse current ripple

2) polarity: positive/negative

3) repetition rate: 1 minute 1 time

4) waveform number: 5 just, 5 negative

5) surge voltage scope: 0～4kV

6) impulse current scope: 0～2kA

7) output equivalent internal resistance: 2 ohm

Result shows, the utility model can pass through 4 grades of tests, meets national standard.

Claims (6)

1. wireless sensor node is without a ground connection antenna feeder Anti-surging device, comprises by with electric capacity c ₁connected antenna connection terminal mouth and the node connectivity port of center signal line, and by air discharge tube GDT, piezo-resistance R _v, Transient Voltage Suppressor TVS and inductance l ₁~ l ₄three grades of parallel circuitss that form, is characterized in that in described three grades of parallel circuitss:

Inductance is passed through in one end of air discharge tube GDT l ₁be connected with antenna connection terminal mouth, pass through inductance simultaneously l ₂with piezo-resistance R _vbe connected, the other end ground connection of air discharge tube GDT; Inductance is passed through in one end of Transient Voltage Suppressor TVS l ₄be connected with node connectivity port, pass through inductance simultaneously l ₃with piezo-resistance R _vbe connected, the other end ground connection of Transient Voltage Suppressor TVS; Piezo-resistance R _vone end connects inductance l ₂and inductance l ₃, other end ground connection; Inductance l ₂and inductance l ₃for other inductance of microhenry level;

Described circuit is directly realized on pcb board; Pcb board two sides without cabling region, cover copper, by arrays of vias, be connected as flood discharge ground, antenna connection terminal mouth, air discharge tube GDT, piezo-resistance R _vwith the earth terminal of Transient Voltage Suppressor TVS by ground pad and flood discharge be connected, the first order air discharge tube branch road printed circuit board line width consisting of air discharge tube GDT is more than or equal to 3.81mm.

2. wireless sensor node according to claim 1, without ground connection antenna feeder Anti-surging device, is characterized in that: described center signal line length is λ/ 2, λfor transmitted signal wavelengths.

3. wireless sensor node according to claim 1, without ground connection antenna feeder Anti-surging device, is characterized in that: described inductance l ₂and inductance l ₃be connected to and between two-stage, play decoupling effect.

4. wireless sensor node according to claim 1, without ground connection antenna feeder Anti-surging device, is characterized in that: described electric capacity c ₁resistance to pressure is more than or equal to the voltage of Anti-surging class requirement.

5. wireless sensor node according to claim 1, without ground connection antenna feeder Anti-surging device, is characterized in that: described air discharge tube GDT, piezo-resistance R _vadopt cross line and flood discharge with the ground pad of Transient Voltage Suppressor TVS and be connected, cross line live width is more than or equal to 1.9mm.

6. wireless sensor node according to claim 1, without ground connection antenna feeder Anti-surging device, is characterized in that: the impedance matching of described device and antenna and node; The equiva lent impedance of described antenna and node is 50 ohm.

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