CN101801152A - Method for realizing electrostatic prevention at radio-frequency port - Google Patents

Abstract

The invention discloses a method for realizing electrostatic prevention at a radio-frequency port. A wire is connected between a microstrip line of the radio-frequency port and the ground, the width of the wire is 0.2-1 mm, and the length is in a way of a quarter-wave line connected in parallel to the microstrip line. The invention effectively inhibits the static signal input to the radio-frequency port, thereby realizing the function of electrostatic prevention at a radio-frequency module port. The invention has the advantages of simple circuit, small size, low cost, simple method, easy realization and high effectiveness.

Description

A kind of method that realizes electrostatic prevention at radio-frequency port

Technical field

The present invention relates to radio-frequency module, especially relate to the method that a kind of radio-frequency module is realized electrostatic prevention at radio-frequency port.

Background technology

Development along with the radio frequency design field, radio frequency applications has entered our various fields in life, the reliability design of radio-frequency module requires also more and more higher, and the antistatic design is as requirement the most basic in the reliability design, also be subject to the people's attention further, the radio-frequency module of every field designs all designing requirements of ports having antistatic now.

The method of conventional radio frequency port antistatic mainly adopts the mode of diode clamp to realize; parallel diode is to ground on the microstrip line of prevention at radio-frequency port; when electrostatic signal is higher than certain amplitude; diode current flow; electrostatic signal is imported into ground level, thereby realizes the purpose of protection radio-frequency module internal components.Be illustrated in figure 1 as traditional electrostatic prevention at radio-frequency port mode, the device of realizing electrostatic-proof function among the figure is the diode of a pair of antiparallel structure, realize electrostatic signal is imported the function of ground level by mode on the prevention at radio-frequency port microstrip line that diode is connected in parallel on, the method will be brought all drawbacks of cost, volume and aspect of performance.But this antistatic circuit also is not suitable for existing the prevention at radio-frequency port of high power signals, because in the prevention at radio-frequency port of high power signals, when radiofrequency signal reaches certain amplitude, equally also can cause diode current flow, radiofrequency signal is taken as electrostatic signal and suppresses.In addition, in traditional anti-static method, there are parameters such as parasitic capacitance, stray inductance in diode self, cause the antistatic circuit that the index of radio frequency code book body is brought influence, cause the complexity of radio-frequency (RF) match to increase and the loss of radiofrequency characteristics, therefore tradition adopts the circuit of diode antistatic to have circuit complexity, cost height, take factors such as volume is big, and these factors have very big drawback today low-cost, small size continuous the pursuit.

Summary of the invention

Be intended to solve the various drawbacks of conventional radio frequency port anti-static precautions, the purpose of this invention is to provide a kind of method of simple and effective realization electrostatic prevention at radio-frequency port.

In order to achieve the above object, the present invention adopts following technical scheme: a kind of method that realizes electrostatic prevention at radio-frequency port, between the microstrip line of prevention at radio-frequency port and ground, be connected lead, and described conductor width is 0.2mm-1mm, length is

Wherein, the computing formula of λ is as follows:

$\mathrm{\λ}=\frac{c}{f\sqrt{E_{\mathrm{eff}}}}$

Wherein,

The c-light velocity;

The operating frequency of f-radio-frequency module;

E _Eff-effective dielectric constant, its computing formula is as follows:

$E_{\mathrm{eff}}=\frac{{\mathrm{\ϵ}}_r+1}{2}+\frac{{\mathrm{\ϵ}}_r-1}{2}[{(1+12\frac{h}{w})}^{-1/2}+0.04{(1-\frac{h}{w})}^2]$

Wherein,

ε _r-medium dielectric constant;

The h-dielectric thickness;

The w-conductor width.

The radiofrequency signal of described prevention at radio-frequency port is that frequency is greater than 4500MH _ZRadiofrequency signal.

Described lead directly is printed on the circuit board of radio-frequency module.。

The present invention is by being connected lead between the microstrip line of prevention at radio-frequency port and the ground; the length of this lead is quarter-wave; promptly quatrter-wavelength line in parallel is realized the antistatic of prevention at radio-frequency port to the mode on ground on the microstrip line of prevention at radio-frequency port; when there is the static input in prevention at radio-frequency port; electrostatic signal can be directly transferred to ground level by quatrter-wavelength line; can not enter radio-frequency module inside by microstrip line; thereby realize the purpose of protection radio-frequency module internal components; simultaneously; quatrter-wavelength line is equivalent to open-circuit condition in the radio frequency operation frequency band; can not produce any influence to the radiofrequency characteristics of module; because quatrter-wavelength line is directly to be printed on the PCB when making printed circuit board (PCB) (PCB), so also do not have the increase of any cost.Therefore the electrostatic-proof function that the present invention uses simply, technical scheme has effectively realized prevention at radio-frequency port cheaply.

Conductor length of the present invention is that quarter-wave is that lead is a quatrter-wavelength line, because the operating frequency of this wavelength and radio-frequency module has corresponding relation, therefore the method for the quatrter-wavelength line antistatic mode of distinguishing radiofrequency signal and electrostatic signal from traditional employing signal amplitude is changed into and is adopted frequency to distinguish radiofrequency signal and electrostatic signal, because radio frequency signal frequency is higher, generally greater than 450MHz, and the electrostatic signal frequency is lower, be generally less than 200MHz, so realize that according to frequency the antistatic of prevention at radio-frequency port is feasible, the electrostatic signal that quatrter-wavelength line is lower with respect to frequency can be considered the state that is shorted to ground, can effectively electrostatic signal be imported ground level, with respect to the radiofrequency signal in the radio frequency operation frequency band then is open-circuit condition, can the characteristic of radiofrequency signal not had any impact.Therefore the present invention can realize the method for the electrostatic prevention at radio-frequency port that volume is little, cost is low, simple according to this principle.

The invention has the beneficial effects as follows: the present invention effectively suppresses the electrostatic signal of prevention at radio-frequency port input by the mode of quatrter-wavelength line in parallel on microstrip line, thereby realizes the electrostatic-proof function of radio-frequency module port.The present invention has also that circuit is simple, volume is little, cost is low; Method simply, is easily gone effective advantage.

Description of drawings

The present invention will illustrate by example and with reference to the mode of accompanying drawing, wherein:

Fig. 1 is a conventional radio frequency port antistatic implementation;

Fig. 2 is that the present invention realizes the circuit diagram that the electrostatic prevention at radio-frequency port method is used.

Embodiment

Disclosed all features in this specification, or the step in disclosed all methods or the process except mutually exclusive feature and/or step, all can make up by any way.

Disclosed arbitrary feature in this specification (comprising any accessory claim, summary and accompanying drawing) is unless special narration all can be replaced by other equivalences or the alternative features with similar purpose.That is, unless special narration, each feature is an example in a series of equivalences or the similar characteristics.

See shown in Figure 2, prevention at radio-frequency port is the prevention at radio-frequency port of radio-frequency module, between radio-frequency module internal circuit and the prevention at radio-frequency port microstrip line is arranged, between the microstrip line of prevention at radio-frequency port and ground, be connected a lead and realize electrostatic prevention at radio-frequency port, this conductor width 0.2mm-1mm, conductor width is determined according to the cloth space of a whole page is long-pending, but in general, conductor width is more little, its influence to radio circuit itself will be more little, this conductor length is a quarter-wave, and in other words, i.e. the present invention is the antistatic that quatrter-wavelength line in parallel is realized prevention at radio-frequency port to the mode on ground on the microstrip line of the prevention at radio-frequency port of radio-frequency module.When there is the static input in prevention at radio-frequency port; because the electrostatic signal frequency is lower; quatrter-wavelength line is equivalent to direct short-circuit to ground; electrostatic signal can be directly transferred to ground level by quatrter-wavelength line; can not enter radio-frequency module inside by microstrip line; thereby realize the purpose of protection radio-frequency module internal components; simultaneously; because radio frequency signal frequency is higher; and the length of quatrter-wavelength line is to calculate according to the radio-frequency module actual operating frequency to get (face computing formula as follows); so; quatrter-wavelength line is equivalent to open-circuit condition in the radio frequency operation frequency band of radio-frequency module; can not produce any influence, because quatrter-wavelength line is directly to be printed on the PCB, so do not have the increase of any cost when making printed circuit board (PCB) (PCB) to the radiofrequency characteristics of radiofrequency signal yet.

This method may further comprise the steps when specifically implementing:

1, according to product actual volume needs, the width W of selected lead (quatrter-wavelength line), generally choosing the W scope is 0.2mm-1mm.

2, by calculating, draw lead (quatrter-wavelength line) length of particular radio-frequency working band

Wherein, the computing formula of λ is as follows:

$\mathrm{\λ}=\frac{c}{f\sqrt{E_{\mathrm{eff}}}}$

Wherein,

The c-light velocity;

The operating frequency of f-radio-frequency module;

The Eeff-effective dielectric constant, its computing formula is as follows:

$E_{\mathrm{eff}}=\frac{{\mathrm{\ϵ}}_r+1}{2}+\frac{{\mathrm{\ϵ}}_r-1}{2}[{(1+12\frac{h}{w})}^{-1/2}+0.04{(1-\frac{h}{w})}^2]$

Wherein,

ε _r-medium dielectric constant;

The h-dielectric thickness;

The w-conductor width.

Width w and the length of calculating gained according to lead (quatrter-wavelength line)

When carrying out radio-frequency module PCB design, a segment length in parallel is on the microstrip line of prevention at radio-frequency port

Width is the lead of w and the electrostatic-proof function that ground connection can effectively be realized prevention at radio-frequency port, when carrying out the radio-frequency module design quatrter-wavelength line directly is printed on the pcb board.

As can be seen from Figure 2, diode from conventional radio frequency port anti-static method has been replaced by a lead (conductor length is a quatrter-wavelength line), quatrter-wavelength line is the lower electrostatic signal of blanketing frequency effectively, and for the radiofrequency signal of frequency higher (radiofrequency signal of prevention at radio-frequency port is mainly the radiofrequency signal of frequency greater than 450MHz), because quatrter-wavelength line is equivalent to open circuit in the radiofrequency signal frequency range, so can not produce any influence to radiofrequency signal.Quatrter-wavelength line is along with the frequency difference of the radiofrequency signal of radio-frequency module among Fig. 2, its length is also inequality, so in actual design, quatrter-wavelength line need calculate or emulation, to reach the purpose that the radiofrequency signal of radio-frequency module is not had fully influence.According to the situation of module actual volume, the width of quatrter-wavelength line is generally between 0.2mm-1mm.According to selected length and width, quatrter-wavelength line is broken when carrying out the radio-frequency module design directly is printed on the electrostatic prevention at radio-frequency port function that reaches on the pcb board radio-frequency module, so can not cause the increase of any cost.

The present invention is not limited to aforesaid embodiment.The present invention expands to any new feature or any new combination that discloses in this manual, and a new method that discloses or step or any new combination of process.

Claims (4)

1. method that realizes electrostatic prevention at radio-frequency port is characterized in that: be connected lead between the microstrip line of prevention at radio-frequency port and ground, described conductor length is

Wherein, the computing formula of λ is as follows:

$\mathrm{\λ}=\frac{c}{f\sqrt{E_{\mathrm{eff}}}}.$

Wherein,

The c-light velocity;

The operating frequency of f-radio-frequency module;

The Eeff-effective dielectric constant, its computing formula is as follows:

$E_{\mathrm{eff}}=\frac{{\mathrm{\ϵ}}_r+1}{2}+\frac{{\mathrm{\ϵ}}_r-1}{2}[{(1+12\frac{h}{w})}^{-1/2}+0.04{(1-\frac{h}{w})}^2].$

Wherein,

ε r-medium dielectric constant;

The h-dielectric thickness;

The W-conductor width.

2. the method for realization electrostatic prevention at radio-frequency port according to claim 1 is characterized in that: the radiofrequency signal of described prevention at radio-frequency port is the radiofrequency signal of frequency greater than 4500MHZ.

3. the method for realization electrostatic prevention at radio-frequency port according to claim 1 is characterized in that: described lead directly is printed on the circuit board of radio-frequency module.

4. the method for realization electrostatic prevention at radio-frequency port according to claim 1 is characterized in that: conductor width is 0.2mm-1mm.

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