阅读说明：本技术 环形天线以及环形天线的设计方法 (The design method of loop aerial and loop aerial ) 是由 佐佐木爱一郎 小馆淳一 于 2018-06-08 设计创作，主要内容包括：本发明提供一种环形天线和环形天线的设计方法,即使在无法将与主环路(1)连接的电容(C<Sub>1</Sub>)以及与放大用环路(2)连接的电容(C<Sub>2</Sub>)的至少任意一个设定为最佳值的情况下,通过根据在表示电容(C<Sub>1</Sub>、C<Sub>2</Sub>)的值与电流(I<Sub>2</Sub>)的大小的关系的图中穿过电容(C<Sub>1</Sub>、C<Sub>2</Sub>)的最佳点(C<Sub>1</Sub><Sup>opt</Sup>、C<Sub>2</Sub><Sup>opt</Sup>)并沿着连接电流(I<Sub>2</Sub>)的大小相等的点的等高线的脊的最优C2曲线、最优C1曲线或最优C1直线,设定电容(C<Sub>1</Sub>、C<Sub>2</Sub>),也能够充分地增大流过放大用环路的电流(I<Sub>2</Sub>)的电流值。(The present invention provides the design method of a kind of loop aerial and loop aerial, even if in the capacitor (C that can not will be connect with major loop (1) 1 ) and the capacitor (C that is connect with amplification with loop (2) 2 ) in the case that at least any one is set as optimum value, by according to indicating capacitor (C 1 、C 2 ) value and electric current (I 2 ) size relationship figure in pass through capacitor (C 1 、C 2 ) Best Point (C 1 opt 、C 2 opt ) and along connection electric current (I 2 ) equal-sized point contour ridge optimal C2 curve, optimal C1 curve or optimal C1 straight line, set capacitor (C 1 、C 2 ), it also can fully increase the electric current (I for flowing through amplification loop 2 ) current value.)

1. a kind of loop aerial, which is characterized in that have:

Major loop is the open loop with signal source or reception circuit connection；

Amplification loop is the closed loop with shape identical with above-mentioned major loop；

First resistor is connected in series with above-mentioned major loop；

First capacitor is connected in series with above-mentioned major loop；

Second resistance is connected in series with above-mentioned amplification with loop；And

Second capacitor is connected in series with above-mentioned amplification with loop,

Above-mentioned major loop is equal with the self-induction of above-mentioned amplification loop,

The resistance value of above-mentioned first resistor is the value bigger than the resistance value of above-mentioned second resistance,

Above-mentioned first capacitor and above-mentioned second capacitor at least any one be fixed capacity,

Pass through the resistance value of above-mentioned first resistor, the resistance value of above-mentioned second resistance, the capacitance of above-mentioned first capacitor, above-mentioned The capacitance of two capacitors and above-mentioned self-induction indicate to flow through the size of the electric current of above-mentioned amplification loop,

In the orthogonal coordinates using the capacitance of above-mentioned first capacitor and the capacitance of above-mentioned second capacitor as axis, above-mentioned electric current Size is that the combination of the capacitance and the capacitance of above-mentioned second capacitor of great above-mentioned first capacitor is represented as on making Best Point shown in the capacitance of above-mentioned first capacitor and the capacitance of above-mentioned second capacitor when stating the size maximization of electric current Optimal curve or optimal straight line,

The capacitance of above-mentioned first capacitor and the electricity of above-mentioned second capacitor are determined according to above-mentioned optimal curve or above-mentioned optimal straight line The combination of capacitance.

2. loop aerial according to claim 1, which is characterized in that

Above-mentioned first capacitor is fixed capacity,

Above-mentioned optimal curve is indicated with following formula:

[formula 11]

C₂=f (C₁；ω, L, R₁)

Wherein, C₁It is the capacitance of above-mentioned first capacitor, C₂It is the capacitance of above-mentioned second capacitor, L is above-mentioned major loop and above-mentioned The amplification self-induction of loop, ω are applied to the angular frequency of the signal of above-mentioned major loop, R₁It is the resistance value of above-mentioned first resistor.

3. loop aerial according to claim 1, which is characterized in that

Above-mentioned second capacitor is fixed capacity,

Above-mentioned optimal curve is indicated with following formula:

[formula 12]

C₁=f(C₂；ω, L, R₂)

Wherein, C₁It is the capacitance of above-mentioned first capacitor, C₂It is the capacitance of above-mentioned second capacitor, L is above-mentioned major loop and above-mentioned The amplification self-induction of loop, ω are applied to the angular frequency of the signal of above-mentioned major loop, R₂It is the resistance value of above-mentioned second resistance.

4. loop aerial according to claim 1, which is characterized in that

Above-mentioned second capacitor is fixed capacity,

Above-mentioned optimal straight line is the straight line that across above-mentioned Best Point and slope is -1.

5. according to loop aerial described in any one of claim 2~4, which is characterized in that

It is not the above-mentioned first capacitor of fixed capacity or the second capacitor is variable capacitance, the capacitance of the variable capacitance is adjusted to The value found out according to the capacitance of above-mentioned fixed capacity and above-mentioned optimal curve or above-mentioned optimal straight line.

6. loop aerial according to claim 1, which is characterized in that

Above-mentioned first capacitor and above-mentioned second capacitor are all fixed capacities,

The combination of the capacitance of above-mentioned first capacitor and the capacitance of above-mentioned second capacitor is the capacitance from above-mentioned first capacitor It is shortest combination that point shown in capacitance with above-mentioned second capacitor, which arrives above-mentioned optimal curve or the distance of above-mentioned optimal straight line,.

7. loop aerial according to claim 1, which is characterized in that

The capacitance of above-mentioned first capacitor and the capacitance of above-mentioned second capacitor are the values or above-mentioned optimal on above-mentioned optimal curve Value on straight line.

8. a kind of design method of loop aerial, the loop aerial have:

Major loop is the open loop with signal source or reception circuit connection；

Amplification loop is the closed loop with shape identical with above-mentioned major loop；

First resistor is connected in series with above-mentioned major loop；

First capacitor is connected in series with above-mentioned major loop；

Second resistance is connected in series with above-mentioned amplification with loop；And

Second capacitor is connected in series with above-mentioned amplification with loop,

The design method of the loop aerial is characterized in that,

Above-mentioned major loop is equal with the self-induction of above-mentioned amplification loop,

The resistance value of above-mentioned first resistor is the value bigger than the resistance value of above-mentioned second resistance,

Above-mentioned first capacitor and above-mentioned second capacitor at least any one be fixed capacity,

Pass through the resistance value of above-mentioned first resistor, the resistance value of above-mentioned second resistance, the capacitance of above-mentioned first capacitor, above-mentioned The capacitance of two capacitors and above-mentioned self-induction indicate to flow through the size of the electric current of above-mentioned amplification loop,

In the orthogonal coordinates using the capacitance of above-mentioned first capacitor and the capacitance of above-mentioned second capacitor as axis, above-mentioned electric current Size is that the combination of the capacitance and the capacitance of above-mentioned second capacitor of great above-mentioned first capacitor is represented as on making Best Point shown in the capacitance of above-mentioned first capacitor and the capacitance of above-mentioned second capacitor when stating the size maximization of electric current Optimal curve or optimal straight line,

The capacitance of above-mentioned first capacitor and the electricity of above-mentioned second capacitor are determined according to above-mentioned optimal curve or above-mentioned optimal straight line The combination of capacitance.

Technical field

The present invention relates to can aid in the loop aerial for expanding the region for the wireless system for having used magnetic field.

Background technique

In recent years, the wireless communication techniques such as NFC (Near Field Communication: near-field communication) are being utilized In Verification System, intentionally limit authentication region come carry out with the intention of user and action linkage service (patent document 1~ 3).In the case where forming authentication region using magnetic field, using loop aerial (coil: coil), by passing through electricity in antennas Stream and on antenna surface the glomerate Distribution of Magnetic Field of shape.Sharply than electric wave, having can be clearly for the range attenuation characteristic in magnetic field The advantages of distinguishing the boundary of wireless zone.

From the viewpoint of expanding wireless zone, the range attenuation characteristic sharply in magnetic field is also disadvantage.Magnetic is being utilized In the case where expanding wireless zone in the wireless system of field, need to provide big electric current to antenna, consumption power is very big.

As the means for solving such problems, propose by putting with not increasing consumption electric current using magnetic resonance effect The method (patent document 4,5) in big magnetic field.

Summary of the invention

Problems to be solved by the invention

In order to amplify magnetic field using resonance, need to be separately mounted to the capacitor on 2 loop aerials of close coupling Capacitance is set as value appropriate.In order to which the capacitance of capacitor is set as optimum value, variable capacitance is convenient.It is considering In the case where practical aspect, it is desirable that reliability and cost effective, therefore it is required that utilizing fixed capacity.

But for fixed capacity, it is difficult to which capacitance is set as optimum value.Even if it is therefore desirable to a kind of capacitor The capacitance method for also obtaining bigger magnetic field not exclusively consistent with optimum value.

The present invention is exactly to propose in view of the foregoing, its object is to: even if the capacitor of the incidental capacitor of antenna Value is not exclusively consistent with optimum value, also obtains bigger magnetic field.

The means used to solve the problem

The loop aerial of one embodiment of the present invention is characterized in that having: major loop, is and signal source or reception electricity The open loop of road connection；Amplification loop is the closed loop with shape identical with above-mentioned major loop；First electricity Resistance is connected in series with above-mentioned major loop；First capacitor is connected in series with above-mentioned major loop；Second resistance is put with above-mentioned It is connected in series with loop greatly；Second capacitor is connected in series with above-mentioned amplification with loop, wherein above-mentioned major loop is put with above-mentioned Big equal with the self-induction of loop, the resistance value of above-mentioned first resistor is the value bigger than the resistance value of above-mentioned second resistance, above-mentioned the One capacitor and above-mentioned second capacitor at least any one be fixed capacity, pass through the resistance value of above-mentioned first resistor, above-mentioned The resistance value of two resistance, the capacitance of above-mentioned first capacitor, the capacitance of above-mentioned second capacitor and above-mentioned self-induction indicate to flow The size for crossing the electric current of above-mentioned amplification loop is being with the capacitance of the capacitance of above-mentioned first capacitor and above-mentioned second capacitor In the orthogonal coordinates of axis, the size of above-mentioned electric current is the capacitance of great above-mentioned first capacitor and the capacitor of above-mentioned second capacitor The combination of value is represented as the capacitance and above-mentioned second across above-mentioned first capacitor when maximizing the size of above-mentioned electric current The optimal curve or optimal straight line of Best Point shown in the capacitance of capacitor, determine according to above-mentioned optimal curve or above-mentioned optimal straight line The combination of the capacitance of the capacitance and above-mentioned second capacitor of fixed above-mentioned first capacitor.

Invention effect

According to the present invention, it even if the capacitance of the incidental capacitor of antenna is not exclusively consistent with optimum value, can also obtain Bigger magnetic field.

Detailed description of the invention

Fig. 1 is the figure for indicating the structure of loop aerial of present embodiment.

Fig. 2 is the figure for indicating the equivalent circuit of loop aerial of Fig. 1.

Fig. 3 is the capacitance for indicating the capacitor being connect with major loop and amplification with loop and the electric current for flowing through amplification loop Relationship figure.

Fig. 4 is the optimum capacitance value for indicating to show the capacitor of amplification loop when connecting fixed capacity with major loop Curve figure.

Fig. 5 is the optimum capacitance value for indicating to show the capacitor of major loop when connecting fixed capacity and amplification with loop Curve figure.

Fig. 6 is the figure for indicating to carry out the curve of Fig. 5 approximate resulting straight line.

Fig. 7 is the figure for indicating the structure of other loop aerials of present embodiment.

Specific embodiment

Hereinafter, using Detailed description of the invention embodiments of the present invention.

Fig. 1 is the figure for indicating the structure of loop aerial of present embodiment.

Loop aerial shown in FIG. 1 is the loop aerial of resonance type, has major loop 1 and amplification loop 2.

Major loop 1 is the coil on the rodlike bar 3 formed by magnetic substance or insulator.The number of turns of major loop 1 It is 1 or more, in the example in fig 1, the number of turns is 5.Resistance R₁With capacitor C₁It is connected in series with major loop 1.Major loop 1 is that have to use In the open loop of connecting signal source 5 or terminal T, T for receiving circuit (not shown).

Amplification loop 2 is the coil from positioning away from from major loop 1 on bar 3.The amplification circle of loop 2 Number is 1 or more, and in the example in fig 1, the number of turns is 5.Resistance R₂With capacitor C₂It is connected in series with amplification loop 2.Loop is used in amplification 2 be the closed loop for not having terminal.

Major loop 1 is identical with the geometry of loop 2 with amplification.Therefore, the self-induction L of both sides is equal.In addition, major loop 1 The same position on bar 3 can also be wound into amplification loop 2.

If the electric current I of supply exchange from signal source 5 to major loop 1₁, then since major loop 1 and amplification are between loop 2 Mutual inductance, in amplification with the electric current I for flowing through exchange in loop 2₂.If making resistance R₂Resistance value be less than resistance R₁Resistance value, Then electric current I₂Size become than electric current I₁Size it is bigger.Thereby, it is possible to expand the area in the magnetic field generated by loop aerial Domain.

In addition, Fig. 1 shows connect signal source 5 with terminal T, T of major loop 1 and loop aerial is used as transmission antenna Structure, but also can replace signal source 5 and circuit will be received and connect with terminal T, T, loop aerial is used as receiving antenna.At this In the case of, due to from external received magnetic field, in amplification with putting aside big electric current I in loop 2₂.Since there are mutual inductances, so stream Cross the electric current I of major loop 1₁Also than amplification loop 2 are not present the case where is big.Therefore, from sending side, the region in magnetic field is expanded It is big.

Then, illustrate for making electric current I₂Maximized capacitor C₁、C₂Optimum value.

Electric current I₂Size depend on signal source 5 generation signal frequency f, resistance R₁, resistance R₂, capacitor C₁, capacitor C₂ And multiple elements such as loop shape.Therefore, it is desirable that adjustment resistance R₁, resistance R₂, capacitor C₁, capacitor C₂Each value, make electricity Flow I₂It maximizes.

In resistance R₂Value specific resistance R₁Value it is small in the case where, if by capacitor C₁、C₂Value be set as according to following public affairs The optimum value C that formula (1), (2) are found out₁ ^opt、C₂ ^opt, then can make electric current I₂It maximizes.

[formula 1]

[formula 2]

Wherein, ω is the angular frequency for the signal that signal source 5 generates.

It is analyzed or is simulated by the equivalent circuit of the loop aerial to Fig. 1, can easily find out electric current I₂It is big It is small.In Fig. 2, the equivalent circuit of the loop aerial of Fig. 1 is indicated.

In Fig. 3, capacitor C obtained from the equivalent circuit of analysis chart 2 is indicated₁、C₂Value and electric current I₂Size pass System.The frequency f of the signal generated from signal source 5 is set as 10MHz by Fig. 3, and voltage Vin is set as 1V, and major loop 1 and amplification are used The self-induction L of loop 2 is set as 1 for sense, by resistance R₁100 Ω are set as, by resistance R₂It is set as 1 Ω, analysis equivalent circuit is depicted and obtains Result.In Fig. 3, respectively by capacitor C₁、C₂Value as horizontally and vertically, with connection electric current I₂Equal-sized point Contour (electric current I₂Contour) indicate capacitor C₁、C₂Value and electric current I₂Size relationship.

If above-mentioned condition is used for formula (1), (2), capacitor C shown in following formula (3) can be obtained₁、C₂Most Good value C₁ ^opt、C₂ ^opt。

[formula 3]

If observing Fig. 3, know in capacitor C₁、C₂Value when meeting formula (3), electric current I₂Really become maximum (50mA).That is, in order to make electric current I₂It maximizes, needs to capacitor C₁、C₂Both sides use variable capacitance, and be finely adjusted to make Capacitor C₁、C₂Capacitance and formula (3) value it is completely the same.

But to capacitor C₁、C₂At least any one, sometimes can not be by capacitor C using in the case where fixed capacity₁、 C₂It is set as optimum value C₁ ^opt、C₂ ^opt.In the present embodiment, to capacitor C₁、C₂At least any one used fixed electricity In the case where appearance, electric current I can be made by finding out₂The optimal value of maximization determines capacitor C according to optimal value₁、C₂Capacitance.

Firstly, considering capacitor C₁It is set as fixed capacity, by capacitor C₂The case where being set as variable capacitance.That is, can not be to capacitor C₁Value be finely adjusted, but can be to capacitor C₂Value be finely adjusted.

It, can be by electric current I by the equivalent circuit of analysis chart 2₂It is expressed as capacitor C₁、C₂Function.Accordingly, it is considered to following The equation of formula (4).

[formula 4]

If specific formula for calculation (4), capacitor C is solved₂, then following formula (5) are obtained.

[formula 5]

C₂=f (C₁；ω, L, R₁) (5)

Wherein, by function f (C；ω, L, R) it is defined as following formula (6).

[formula 6]

Curve shown in formula (5) is known as optimal C2 curve.Fig. 4 be marked and drawn on contour shown in Fig. 3 it is optimal The figure of C2 curve.Optimal C2 curve indicates and can not adjust the capacitor C of capacitance₁The corresponding optimal capacitor C of value₂Value. That is, even if capacitor C₁Fixed capacity and can not be by capacitor C₁Value be adjusted to optimum value shown in formula (3), by by capacitor C₂Value fine tuning be the value that is found out according to formula (5), can also make electric current I₂Size maximization.

Then, consider capacitor C₁It is set as variable capacitance, by capacitor C₂The case where being set as fixed capacity.That is, and above situation On the contrary, can be to capacitor C₁Value be finely adjusted, but can not be to capacitor C₂Value be finely adjusted.

In the present case, consider the equation of following formula (7).

[formula 7]

If specific formula for calculation (7), capacitor C is solved₁, then following formula (8) are obtained.

[formula 8]

C₁=f (C₂；ω, L, R₂) (8)

By function f (C；ω, L, R) it is defined as formula (6).

Curve shown in formula (8) is known as optimal C1 curve.Fig. 5 be marked and drawn on contour shown in Fig. 3 it is optimal The figure of C1 curve.Optimal C1 curve indicates and can not adjust the capacitor C of capacitance₂The corresponding optimal C of value₁Value.Even if electric Hold C₂It is fixed capacity, by by capacitor C₁Value fine tuning be the value that is found out according to formula (8), can also make electric current I₂Size Maximization.

If observation Fig. 4, Fig. 5, any one curve of optimal C2 curve and optimal C1 curve is all across making electric current I₂The maximized capacitor C of size₁、C₂Best Point (C₁ ^opt、C₂ ^opt) and along electric current I₂Contour ridge curve.

In addition, knowing that optimal C1 curve can be with across Best Point (C if observation Fig. 5₁ ^opt、C₂ ^opt), slope is -1 Straight line it is approximate.Such straight line is indicated with following formula (9).

[formula 9]

Straight line shown in formula (9) is known as optimal C1 curve.Fig. 6 is that optimal C1 is marked and drawed on contour shown in Fig. 3 The figure of straight line.If observation Fig. 6, known to optimal C1 straight line optimal C1 curve shown in fig. 5 approximate well.Therefore, may be used With with the alternative optimal C1 curve of optimal C1 straight line.Even if capacitor C₂It is fixed capacity, by by capacitor C₁Value fine tuning for according to public affairs The value that formula (9) is found out, can also make electric current I₂Size maximization.If can easily be found out using optimal C1 straight line The capacitor C that should be set₁Value.To capacitor C₁Value carry out automatically controlling in the case where, optimal C1 straight line is useful.

Then, consider capacitor C₁、C₂Any one the case where being all fixed capacity.

For the purpose of seeking to reduce cost, the case where not using variable capacitance completely is considered.It is serial from E3 series to E192, Fixed capacity can be selected from the product line unified between manufacturers.However, it is necessary to from the fixed electricity of discrete value Capacitor C is selected in appearance₁、C₂, as a consequence it is hardly possible to selection and capacitor C₁、C₂The completely the same fixed capacity of optimum value.In addition, Being extremely difficult to achieve makes capacitor C₁、C₂Value be located on previously described optimal curve or on optimal straight line for capacitor C₁、C₂ Fixed capacity.

Therefore, in the present embodiment, in capacitor C₁、C₂Both sides using in the case where fixed capacity, using becoming candidate Capacitor combination (C₁ ⁰、C₂ ⁰) in the distance d (C for leaving optimal curve or optimal straight line₁ ⁰、C₂ ⁰) it is shortest combination.Pass through Formula (5), (6), (8), (9) provide the function for indicating optimal curve and optimal straight line, therefore can find out d (C₁ ⁰、C₂ ⁰).Especially It is can according to the following formula (10) easily find out with formula (9) shown at a distance from optimal C1 straight line.

[formula 10]

Then, illustrate other loop aerials of present embodiment.

Fig. 7 is the figure for indicating the structure of other loop aerials of present embodiment.

Loop aerial shown in Fig. 7 is the loop aerial of resonance type, has major loop 1 and amplification loop 2.

Major loop 1 and amplification loop 2 are being formed on planar substrates (not shown) this by loop aerial shown in Fig. 7 Point, it is different from loop aerial shown in FIG. 1.

Major loop 1 is configured on the planar substrates formed by insulator.Resistance R₁With capacitor C₁With 1 company of series connection of major loop It connects.Major loop 1 is with the open loop for connecting signal source 5 or terminal T, T for receiving circuit (not shown).

Amplification loop 2 and major loop 1 extremely closely configure on same plane substrate.Resistance R₂With capacitor C₂With put It is connected in series with loop 2 greatly.Amplification loop 2 is the closed loop for not having terminal.

Major loop 1 is identical with the geometry of loop 2 with amplification, and therefore, the self-induction L of both sides is equal.

If the electric current I of supply exchange from signal source 5 to major loop 1₁, then since major loop 1 and amplification are between loop 2 Mutual inductance, in amplification with the electric current I for flowing through exchange in loop 2₂.If making resistance R₂Resistance value be less than resistance R₁Resistance value, Then electric current I₂Size become than electric current I₁Size it is big.

In the capacitor C of the loop aerial to Fig. 7₁、C₂In the case that at least any one has used fixed capacity, also with The loop aerial of Fig. 1 similarly, by being set as optimum capacitance value, can make electric current I₂Size maximization.

In addition, amplification loop 2 can be matched in the inside of major loop 1, but both by configuring amplification with loop 2 in Fig. 7 It sets in the outside of major loop 1, it can also be by major loop 1 and the configuration of amplification loop 2 on two faces for clipping planar substrates. Major loop 1 and amplification can be set as 2 or more with the number of turns of loop 2.In the case where the number of turns is set as 2 or more, make major loop 1 With the amplification equal turn numbers of loop 2.

In the loop aerial of Fig. 7, it can also will receive circuit and be connect with terminal T, T and be used as receiving antenna.

As described above, according to the present embodiment, in the capacitor C that can not will be connect with major loop 1₁With with amplification The capacitor C connected with loop 2₂In the case that at least any one is set as optimum value, according to indicating capacitor C₁、C₂Value With electric current I₂Size relationship figure in pass through capacitor C₁、C₂Best Point and along connection electric current I₂Equal-sized point Contour ridge optimal C2 curve, optimal C1 curve or optimal C1 straight line, set capacitor C₁、C₂, thus also can be fully Increase the electric current I for flowing through amplification loop₂Current value.Even if as a result, to capacitor C₁、C₂At least any one use it is cheap Fixed capacity, can also obtain big magnetic field amplification effect.

Description of symbols

1: major loop；2: loop is used in amplification；3: bar；5: signal source.