SK500042013A3 - Non-stationary magnetic field emitter and its location - Google Patents

Abstract

The emitter is designed to create a contactless communication channel (especially RFID / NFC) in a miniature building space. The emitter has an elongated, at least partially ferrite core (1), a conductor (4) with at least two threads (2) is wound on the core (1), the threads (2) are tightly adjacent to each other on the core (1) and an effective width w of one of the thread (2) corresponds to the core radius (1) at the circular core cross-section (1) or to the equivalent radius of the other core shapes (1) to within ± 75%. The winding conductor (4) is flat or the winding comprises a plurality of parallel conductors (41 to 4N) forming one multi-stage thread. The core (1) may be formed by a ferrite rod disposed on a non-conductive substrate (6), where the conductors (4) are wound through a ferrite rod and also through a non-conductive substrate. The emitter is located in a removable memory card (5) and / or on a PCB board (10), and / or on a SIM card (9), and / or in a battery (11).

Description

Non-stationary magnetic field emitter and its location

Technical field

The present invention relates to a non-stationary magnetic field emitter which constitutes a 5 miniature antenna replacement on a flat carrier with a low available installation height, in particular on the surface of a removable memory card such as a microSD card or a SIM card. The antenna is particularly useful for additionally establishing a contactless NFC / RFID communication channel in a mobile phone. The solution is designed primarily for payment applications made using a mobile communication device. In principle, however, the new type of radiator according to the invention can also be used in other applications and devices, especially where there is insufficient space to enlarge the antenna, and where the antenna is shielded by surrounding elements of different structure and properties according to different environmental conditions .

BACKGROUND OF THE INVENTION

The location of the antenna directly on the removable card, which is intended to be inserted into the slot of the mobile communication device, is known from the published patents, e.g. DE 10252348 A1, WO 03/043101 A3. These disclosures describe the general possibility of using the antenna on the card, but do not contain sufficient antenna specification in situations where the removable card is shielded by adjacent parts of the mobile communication device, in particular the mobile phone.

In particular, the described NFC antennas are in the form of wire loops on the surface, with all available surfaces being used for small dimensions. When the NFC antenna is placed on relatively small areas, the antenna is in the form of an inscribed spiral rectangular package with rounded corners that substantially copies the outer shape of the available area. With this arrangement, a quite typical shape of NFC antennas has been created.

Antennas for NFC and RFID transmissions are therefore basically flat, with a loop of edges along the usable area such as according to DE102008005795,

CN102074788, US2009314842, CN101577740, CN201590480, CN201215827

CN201515004, JP2010102531, JP2011193349, CN201830251, KR20100056159,

KR100693204, WO2010143849, JP2004005494, JP2006304184, JP2005033461,

JP2010051012. When implementing such an antenna on a removable memory card, the flat character of the card is naturally utilized, and such an antenna is unwound by looping on an accessible portion of the largest area, such as e.g. WO2012019694,

DE102010052127, DE102004029984, CN101964073. However, solutions with frame antennas on available surfaces do not produce the desired result and various applicants therefore complement the antenna with other elements such as ribs, layers and the like. These solutions increase the complexity of the design and yet do not create a reliable communication channel. Solutions of miniature antennas are known, for example according to US 2007/0194913 A1, which solve the problem of shrinking the antenna and its attachment to the substrate, but such applications do not solve the problem of different antenna shielding. Transferring knowledge of existing NFC antennas to an area with low available space does not produce the desired results, since when miniaturized below a certain level, the properties of the resulting antenna do not change linearly.

The published patent applications of Logomotion describe the arrangement of the antenna and the individual layers of the removable memory card in order to adjust the radiation and reception characteristics of the antenna so that a reliable communication channel can be established even with different shaded card slots. The technical task defined in this way led to the development of several technical solutions, which, however, led to satisfactory results only in some mobile phones, and consequently the developmental current dropped towards the creation of larger, additional antennas on the mobile phone body outside the shaded areas. These additional antennas (CN201590480 U), for example in the form of stickers, can be contactless with the base antenna on the card, but the versatility of such an arrangement remains low and the complexity of the application in the hands of the ordinary user remains unpleasant.

The antenna placed directly on the removable card has very limited dimensional possibilities. Mobile phones have microSD card slots, which significantly limits the size of the antenna that can be placed directly on the card. Placing a removable card in highly shaded slots, such as under a mobile phone battery, significantly worsens the broadcasting conditions from the antenna on the card.

The use of baffle layers, foils has only a narrowly specific effect and is little universal when used in various mobile phone designs.

Basic theoretical and scholarly publications are of the opinion that at low thickness and available area the RFID or NFC antenna should be designed as a flat antenna, for example according to RFID HANDBOOK, Klaus Finkenzeller, 2010 according to Figures 2.11, 2.15, 12.7, 12.9, 12.11, 12.13. According to the same source (Section 4.1.1.2 Optimal Antenna Diameter / Physical Principles of RFID Systems), it is most optimal if the radius of the transmitting antenna corresponds to the square root of the desired antenna range.

Since metal parts and covers are more often used in mobile phones, there is a problem with the design and location of the NFC antenna even in a situation where the NFC element is already foreseen when designing a mobile phone or similar communication element. A solution is desired which will ensure a high throughput of the transmitted signal from the PCB board of the mobile phone or from the element on the removable memory card, which may be shielded by surrounding metal elements of the mobile phone, for example a battery or metal cover.

SUMMARY OF THE INVENTION

The aforementioned drawbacks are substantially eliminated by a non-stationary magnetic field emitter in the function of an antenna, in particular an antenna on a flat substrate within a mobile communication device, especially a mobile phone, wherein the emitter has the elongated, at least partially ferrite core for the core is a wound conductor with at least two turns, the threads are placed close to each other on the core and the effective width of one thread corresponds to the radius of the core at a circular core cross-section with a deviation of + - 75%. For other core cross-sections, the effective width of one thread corresponds to an equivalent radius also with a deviation of + - 75%.

A ratio of 0.25 to 1.75, preferably 0.5 to 1.5, particularly preferably 0.85 to 1.15, between the effective width of one thread and the radius of the core respectively. the equivalent radius of the core is not merely an expression of dimensional dimensioning. As it appeared during the invention of the radiator, it is precisely the observance of the above-mentioned dimensional relationship that, in connection with the tight winding of the conductor, results in a synergistic interaction of several physical laws. Within this range and in the vicinity of said interval, a directional interaction of the magnetic field is produced from the individual conductor parts and from the individual windings without creating undesired swirling fields, wherein the magnetic field in the core is amplified and cannot flow along the winding outside the end faces of the core.

The ratio between the effective width of a single thread and the radius of the core has not been a previously observed parameter for radiators or antennas. In the case of the prior art core antennas, the effective width of one thread is less than 0.001 to 0.1 times the radius of the core. Preferred for the emitter of the present invention will be a ratio close to 1, i.e. w = D / 2, where D is the core diameter and the core diameter, respectively. equivalent core diameter.

The radiator is used as a replacement for a conventional electromagnetic antenna, but on the other hand the non-contact NFC or RFID link is a signal received and transmitted by a standard NFC or RFID receiving means. The source of the emitter is to create an intense and homogeneous magnetic field. If the emitter is used on a microSD card or subscriber identity module (SIM), the core cross-sectional dimension (eg core height dimension) will be less than 1 mm. When using a microSD card emitter, the core length is more than 7 times the smaller core cross-sectional dimension. The core length will not normally exceed 15 mm. The radiator will primarily be used to create an additional contactless communication channel. The radiator of the present invention will also generate an electric field, but this will not be a signal carrier on the receiving device side, but will only be an insignificant component of the field that will not substantially penetrate the shielding of the guest device. Miniaturization of an antenna with a core thickness of less than 1 mm creates technical problems that cannot be solved only by proportional sizing of commonly known larger antenna designs.

First of all, the use of threads having an axis parallel to the carrier surface of the present invention results in a substantial decrease in the diameter of the thread, contrary to the general RFID HANDBOOK requirement for increasing the antenna range, Klaus Finkenzeller, 2010.

The core is elongated in the longitudinal direction so that the ends of the core are as far apart as possible within the available space on the surface. The core may be curved, but the best results are obtained with a straight rod core, where the magnetic field lines close off the radiator as long as possible and thus tend to flow out of the shielded space. The core ferrite should have a relative permeability set such that the emitter inductance is at a level of 600nH to 1200nH, preferably near 750nH. Taking into account this criterion, the ferrite core may have a permeability in the range of 30 to 300. The permeability of the core will be adjusted according to the technological possibilities of the maximum permissible magnetic saturation and the dimensional possibilities of the core cross-section. The term ferrite is to be understood as any material which enhances the characteristics and properties of the magnetic field.

It is essential that the coils are wound closely next to each other in order to prevent the magnetic field from emitting from the core outside the core ends. The thread conductors themselves form the core shield. The conductors of adjacent threads prevent the formation of a swirling magnetic field of the conductor between adjacent conductors. There is essentially only a gap in the form of conductor insulation thickness between adjacent threads. The metallic conductor threading assembly thereby provides a core shielding that directs the magnetic field flow.

In order to achieve a condition where the magnetic field flows from the emitter even through slight gaps between the shielding elements in the host device, it is necessary that the magnetic field in the core be as homogeneous as possible while at the same time having the greatest intensity with a small core cross section. The requirement of homogeneity is related to the finding that with small dimensions of the emitter, the unequal magnetic field intensity within the core manifests itself in large losses. High magnetic field strength is required in order to achieve high environmental penetration of the magnetic field.

Both requirements are best met by an arrangement in which the effective width of one thread corresponds to the radius of the core at the circular cross-section of the core. The effective width of one thread is the dimension by which the thread conductor projects on the core length.

The conductor may have different cross-sections, therefore the effective width of one thread may be different from the actual width of the conductor. In the most common case where the thread conductor has a circular or simple flat and non-interlaced shape, the effective thread width will be substantially equal to the width of the conductor. If a flat conductor is used so that a part of the conductor of one thread is covered by the edge of an adjacent conductor, the effective width of the conductor will be the width of the edgeless conductor already overlapping the adjacent conductor. In essence, it will be that part of the width of the conductor that will be in contact with the core when the conductor is flat. With a dense, tight winding, the effective width of the conductors of one thread will coincide with the thread pitch.

The requirement that the effective width correspond to the radius of the core, respectively. equivalent to the radius of the core, it is to be understood that the effective width should be substantially equal to the radius of the core. With small overall dimensions of the core cross-section, a small technological deviation also causes a deviation from the rule, but still achieves a benefit, or at least a sufficiently usable effect from said principle. Consequently, a condition where the effective thread width is in the range of 0.6 to 1.4 times the radius of the core, resp. equivalent core radius. In the range of 0.6 to 1.4, the maximum magnetic power drop is less than 10%. Even with a relatively large range of ratios (0.25 to 1.75), a sufficiently convincing and advantageous result is achieved, as the prior art involves the order of magnitude of the effective width and core radius ratios (less than 0.001 to 0.1).

By observing the dimensional relationship we create a radiator with the effect of a magnetic gun, where the magnetic field is emitted very intensively from a small cross-sectional area of a miniature core.

The equivalent radius of a non-circular cross-section expresses the radius that a circle would have if it had the same area as the cross-section with the shape of that non-circular cross-section. Thus, the equivalent radius of the non-circular cross-section is the area equivalent radius. For example, with an exactly square cross-section of the core with the side "a", the equivalent radius r _e = a / ^ π is equivalent. For a rectangular cross-section with dimensions "a", "b" without rounding the edges, the radius r _e = ^ (ab / π) is equivalent. The core may have a square, rectangular, circular, elliptical cross-section, or it may have a cross-section formed by a combination of said shapes. Most often, the core shape will be designed to utilize the space, usually the core will have a cross-section with a circular shape, or have an elliptical shape, or have a cross-section at least partially rectangular, in particular a square or rectangular shape, preferably with rounded corners.

For the sake of simplicity, the emitter will be designed to be wound with a wire w w along the entire length of the core I and then has N = I / w turns. The source U has an internal impedance of Z. The radiator Ls has a series loss resistor Rs and is connected to the source U via the adjusting member C1 / C2 of FIG. Figure 1 shows the transformation of the serial circuit Ĺs + Rs to parallel Lp // Rp, where Rp = (1 + Q ^) R ^S and ~ ( ¹

If we assume that the quality of the resonant circuit Q »1, then we can simplify the relations to the form L = Ls and Rp = Q ² Rs. .

n _ U ²

The power from the source to cover the losses is then Γη--. The inductance Ls can be adjusted ⁱⁿ ReZ) if Rs is smaller than the real part of Re (Z). Under this assumption, the current I _L is then flowing through the inductance _{L L}

The magnetic field in the center of the emitter is then

where N is the number of turns. The relation is further adjusted to the shape where Rin is the normalized winding loss per thread and has character

R _1N = aE? ^Luf + r

Figure 2 then shows the dependence of Rs on the width of the winding w divided by the core diameter. Figure 2 shows the point C corresponding to the ratio w / D = 0.5. The maximum winding width is wmax = 2nD. With a wider width, the wires would already overlap each other. The rest of the graph covers the area from N = 2.5 turns to N = 55 turns.

The graph according to Figure 3 shows the magnetic field intensity in the center of the emitter. The maximum value (point A in the graph) of the magnetic field is if w = 0.5.D, ie if the effective thread width corresponds to the radius of the radiator core. To the left of point B (very thin wire width w), the resistance Rs is greater than the internal impedance Re (Z), and the power supply is unable to provide the required power to the load, resulting in a significant decrease in magnetic field strength. Point B is also interesting in that, at that time, the capacitance C2 = 0, the resulting resonant circuit is simplified to the series resonant circuit of Figure 4. However, this simplified circuit does not provide maximum magnetic power. The magnetic field to the right of point A decreases because the winding, whose width w increases, makes an increasingly larger angle with the axis of the radiator core.

Based on the Biot-Savart law, the vector Hx is calculated as the vector product of the current L and the vector r, which in our case forms the axis of the radiator core. Integrates along the entire winding curve x (helix w)

I f dx c 1 f dx cos «

This results in the finding that, with a very wide winding, the angle begins and significantly affects the intensity of the magnetic field with the coefficient cos a. To the left of

A is the effect of the angle and is negligible, but the losses Rs as shown in Figure 2 are starting to show markedly. Starting at w = D / 2, the losses Rs are starting to increase significantly (point C). From the graph we can read that the optimum inductance of the emitter is approximately at L = 750nH. Given the dimensions of the emitter, it is necessary to select the permeability p so that at w = D / 2 the inductance is just L = 750nH.

The use of a single-stage winding of a classical circular cross-section leads to a problem with the bending radius of the conductor since the effective conductor width, now coincident with the conductor diameter, should substantially correspond to the radius of the core, for example the circular core. The permitted minimum bending of the conductor is more than twice the bending radius. If we then have only one millimeter of installation space for the radiator, the maximum core height would be less than half a millimeter, causing technological problems and complications with winding a relatively coarse wire onto a fragile and small core. The winding problems are caused by the ratio of the effective width to the radius of the core of the present invention, since the conductor is to be relatively wide and thus coarse compared to the core dimension.

In order to make better use of the available height of the space while adhering to the basic rule of the present invention (i.e. the dimensional relationship between the effective thread width and the core radius), a solution has been devised using a flat conductor. Its width after winding to the core corresponds to the radius of the core. The flat conductor is more easily wound on the core, while taking up a lot of space in the vertical section. The space can then be better utilized for the radiator core. The flat conductor has a sufficiently low electrical resistance. The flat conductor will have a width exceeding twice the height of the conductor, respectively. driver thickness.

It has further been found that, in a preferred embodiment, the flat conductor can be replaced by an assembly of at least two coiled conductors which, however, still constitute only one thread. The conductors are electrically connected. For example, if you want to replace a flat conductor with an original width / height ratio of 1: 3, use three flat conductors of uniform circular cross-section to replace such flat conductor, winding side by side as if it were a three-stage thread. If we replace the flat conductor with the original cross-section of 1: 8, we use 8 side-by-side round conductors, as if it were an eight-degree thread in mechanical sense. The wires within a single-stage thread would not need to be insulated, since these wires will be electrically connected at the ends of the reels, but for the sake of technological simplicity, the same insulated wire can be used for all wires of that thread. In another arrangement, only the edge conductors of one thread may be electrically insulated, the internally located conductors need not be insulated.

The effort to achieve a homogeneous magnetic field with high intensity, which will emit from the distal ends of the core, is accompanied by a number of contradictory requirements. It is desirable to use as few turns as possible, but as the number of turns decreases, the core length is reduced, while the number of turns is also shielded, while the number of turns decreases the current load required to radiate the signal. Use a flat conductor, or use multi-stage parallel threaded conductors of one thread to suitably eliminate this conflicting requirement.

The miniature emitter may be located on a PCB board inside the mobile communication device, or it may be located within the removable memory card body, or it may be placed on a SIM card, or it may be placed on a battery, or a combination thereof.

When using a radiator according to the present invention directly on a PCB board of a mobile communication device (especially a mobile phone), the radiator provides the advantage in particular that the radiator used as an antenna has miniature dimensions and can be placed almost anywhere on the board. Until now, NFC antennas have been designed specifically for each new mobile phone model, as the antennas encircled a larger area on or around the PCB with their loops. Until now, one manufacturer of several mobile phone models had to use several types of NFC antennas. When using the emitter of the present invention, even when used directly on the PCB, it will be sufficient to use one miniature emitter.

In the case of a radiator on a removable memory card, such a card is intended to be inserted into the expansion slot of the mobile communication device. In such a case, the emitter on the removable memory card substrate is positioned such that the axis of the antenna core is oriented substantially parallel to the surface of the removable card body and the emitter is located at the edge of the removable memory card body outside the contact interface zones. It will be advantageous if the emitter is located along the edge opposite the edge with the contact interface zone of the removable memory card.

It is preferable that the core length, i.e. the core dimension in the direction of the winding axis, be as large as possible within the card's dimensional capabilities, thereby achieving the longest magnetic field lines of the magnetic field and only a minor part of the magnetic flux being closed short.

When placed in the removable memory card body, the core will have a height of up to 1mm, a width of up to 5mm and a length of up to 15mm. With a preferred orientation outside the contact zone, the core will have a rectangular cross section up to a height of 0.7mm, a width of up to 1mm, and a length of up to 11mm.

If the radiator is used on the SIM card, there is more space for the radiator. The SIM card is larger in size than the microSD card and at the same time does not have such a high penetration of electronic elements outside the chip in the contact field. The emitter can be placed in different positions and rotations on the SIM card.

When using the radiator in the battery of the mobile phone, there are more possibilities of positioning and rotating the radiator core. In principle, several lamps can be placed in different locations with different orientation in one battery. The activation of a particular radiator can be selected according to the successive transmission results in that mobile phone.

The signal emitted from the magnetic field emitter of the present invention is received by standard reception means in a given frequency band. For example, if the radiator is intended for NFC transmission between a mobile phone and a POS terminal reader, the antenna on the mobile phone side will be in the form of a ferrite core magnetic field emitter, but a conventional receiving antenna will be located on the NFC reader side of the POS terminal. Conformity with existing, standard devices is important in order to avoid the need to change the hardware widely used on the POS terminals. The hardware change on the mobile phone side is done by inserting a removable card (especially microSD format) into an existing mobile phone expansion slot or inserting a new SIM card or inserting a new battery. The mobile communication device expansion slot is a card slot that does not affect the basic communication function of the device, in particular, but not exclusively a slot for a removable microSD memory card.

From a technological point of view, it will be advantageous if the core consists of a ferrite rod disposed on a non-conductive pad. The non-conductive pad will have a width corresponding to the core width and a length at least equal to the core length. The thread conductors are wound through a ferrite rod and also through a non-conductive pad, whereby the wire winding mechanically holds the core with the non-conductive pad. The non-conductive pad may have connecting surfaces at both ends to connect the winding wires and to connect the antenna to the removable memory card body. On the connecting surfaces, the conductors of the multi-stage winding are interconnected and also these radiator contacts are connected to the conducting circuits of the guest device.

The magnetic field created in the radiator of the present invention has the ability to penetrate even small gaps in the spatial structure of the mobile communication device. Flat gaps, for example, between the card and the card slot, then between the battery body and the adjacent cell phone body are sufficient to penetrate the magnetic field out of the cell phone body. The magnetic field emitted from the emitter will be received on the other side of the communication channel by a conventional antenna, for example in the form of a POS terminal reader. In practice, the emitter will be placed mainly inside a mobile phone which has metal covers in a disadvantageous arrangement. The magnetic field lines emanate from the small gaps between the covers out into the space where the NFC reader will be located. Covers are basically always divisible, often because of the possibility of removing the battery from underneath the cover, leaving gaps between their parts. These are sufficient for the high intensity magnetic field to penetrate out of the emitter of the present invention.

Resonant properties of the radiator can be achieved by adjusting the position and dimensions of the winding conductor so that the winding itself has a suitable capacity, or the entire system of all winding conductors has a suitable capacity, possibly including electromagnetic coupling of the surrounding.

The radiator can be designed to be tuned appropriately under different environmental conditions. If it is in close proximity to electrically conductive materials, the inductance of the radiator will decrease. This feature is used to automatically control the radiated power depending on the environment in which the radiator is placed. This will increase the versatility of the use of the radiator, the distribution of which does not have to take into account the influence of different types of mobile phones. For example, a radiator will be tuned to 15MHz resonance when it is in a metal package. Due to the environment the inductance of the antenna stabilizes, decreases to 1μΗ. However, if placed outside the package the inductance increases to 1.3μΗ and the resonance is shifted to 12MHz. Since the radiator emits power at 14.4MHz, the maximum power is radiated only when its resonance is close to this value because its internal resistance is then

the smallest. However, when placed under a plastic housing, the resonance moves down to 12MHz and the internal resistance increases at 14.4MHz. The radiator will preferably be designed and constructed such that it is set to the maximum transmitting power at the most unfavorable shielding possible, for example, by fully shielding, by frequency and / or inductance and / or internal resistance. Thereafter, reducing the shielding rate by its coupling to the environment will reduce the transmit power at the same input excitation by the fact that the environmental shielding affects the frequency and / or inductance and / or internal resistance of the emitter. Simply for emitting by means of a radiator, we will deliberately use the surrounding metal parts, the absence of which will cause a transmit power reduction, but the emitter will be set so that even at zero shade the emitter transmitting power is higher than the minimum receiving power by standard NFC or RFID receiving means.

The magnetic field emitter of the present invention will in principle be used to transmit a signal from a removable memory card body or from a SIM card body or from a PCD board or a battery. In the opposite direction of communication, when the signal is received on the removable memory card, there is usually no problem with the intensity of the electromagnetic field, since in this direction the transmitting antennas are not dimensionally constrained. In principle, there is therefore no particular need to optimize the transmission path towards the radiator, which will also serve as a receiving antenna. In another embodiment, the radiator may be complemented by a classically wound, separate NFC antenna to receive a signal toward the removable card.

The maximum effective current from the output driver can be in the range of 0.1 - 0.2 Arms, where the maximum allowed current load is based on the card interface standard. The output driver is part of the output stage of the power amplifier. The current in the winding conductor does not exceed 0.8 Arms. The output resistance of the output driver with such a setting and power on the microSD card may be less than 10 Ohm. The specific value of the impedance can vary according to the set ratio of voltages, currents and powers.

The emitter on the card of the present invention has excellent transmission properties in slots of various mobile communication devices, even when the slot is placed under the battery. The measurements have shown that a mobile phone with a removable memory card with a radiator according to the invention is capable of creating a reliable NFC communication channel, while not limiting the directional orientation of the mobile phone relative to the NFC reader. The influence of different mobile phone designs on the reliability of the additionally created contactless channel is suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS

The solution is explained in more detail with reference to Figures 1 to 24. The scale used and the size ratio of the individual elements may not correspond to the description in the examples, and these measures and size ratios cannot be explained as a narrowing scope.

Figure 1 schematically illustrates the transformation of a serial LR circuit to a parallel circuit.

Figure 2 shows a graph of the losses in the coil of a radiator as a function of the ratio of wire width to core diameter.

Figure 3 is a graph showing the magnitude of the magnetic field at the center of the emitter versus the ratio of the winding width to the core diameter.

Figure 4 is a series resonant circuit to which the resulting resonant circuit at point B of the graph of Figure 3 is simplified.

Figure 5 is an axonometric view of a flat cross-sectional emitter. The spacing between the wire windings is shown only for clarity, in fact the winding is arranged close to each other.

Figure 6 is a cross-sectional view of the core and the flat conductor with a single winding. Again, gaps are shown between the windings and between the windings and the core for clarity, in fact, the winding is arranged close to each other and tightly on the core without gaps.

Figure 7 shows a cross-section of a flat conductor with overlapping edges. Gaps are shown between the windings and between the windings and the core for clarity; in fact, the winding is arranged close to each other and tightly on the core without gaps.

Figure 8 shows a cross-section of a core with a multi-stage winding of the conductor where the conductor of all stages of one thread is the same and insulated. For the sake of clarity, a gap is shown between the outer conductors of adjacent threads in Figures 8 to 13, but this does not actually occur in the winding. The gap in the figures is intended to distinguish the conductors into groups of one thread.

Figure 9 shows a cross-section of a core with a multi-stage wire winding, where only the edge conductors of one winding are insulated. Conductors located within one group, one winding are not insulated.

Figure 10 shows the lead of the conductor in a winding on a core with a circular 10 cross section. For the sake of clarity, one conductor 41 is shown, the other conductors being shown only in cross-section. The thread pitch corresponds to half the diameter of the circular core.

Figure 11 is a view of a half-emitter where the winding consists of a flat non-insulated conductor, around which an insulated round cross-section conductor is wound.

Fig. 12 is a view of the end of the radiator windings at the end of the core with a non-conductive pad that is soldered to the substrate of the removable memory card.

Figure 13 shows a detail of the wiring of one thread of wires on the connection plate that is formed on the underside of the non-conductive pad.

Figure 14 shows an example of placing the emitter on a removable microSD format memory card.

Fig. 15 is a side view of the magnetic field radiation diagram with the radiator placed on a removable memory card and inserted into the interior of a mobile phone with metal covers. The radiation diagram in the horizontal plane shows the effort of the magnetic field to push through a narrow slit in the metal package so that the magnetic field lines of the magnetic field close together.

Figure 16 shows examples of four antenna frequency settings in the NFC broadcast band. The resonance curve is represented by a solid line. The apex of the resonant curve represents the resonant frequency i of the antenna and may coincide with the transmit frequency f1 or the receive frequency f2, or may form only the apex of the curve that characterizes the usable frequency band. The frequency f1 of the broadcast is plotted with a dashed line. The reception frequency f2 is plotted with a dashed line. The y-axis represents the input current to the antenna.

Figure 17 shows the impedance parameters of the emitter.

Figure 18 shows an automatic tuning of radiator power where the radiator impedance varies depending on the environment. The curve "a" represents the internal resistance of the system with the radiator placed in the plastic package, the curve "b" applies to the system with the radiator placed in the metal package.

Figures 19 to 22 show SIM cards with various radiators in the card body.

Figure 23 shows the location of the radiator directly on the PCB of the mobile phone. Figure 24 shows the location of the radiator in the cell phone battery.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

In this example of Figures 1, 2, 3, 4, 8, 12, 13, 14, 15 to 18, a rectangular ferrite core 1 radiator structure is described. The core 1 has a length of 9 mm and a cross-section of 0.8 mm x 0.6 mm. A non-conductive pad 6 having a width of 0.8mm and a thickness of 0.04mm is enclosed with the core. On the core 1 and at the same time through the non-conductive washer 6, 21 threads 2 of copper insulated wire are wound close together. In this case, one thread 2 is formed by six parallel conductors 4 with a diameter of 0.05 mm. This replaces the flat conductor of one thread 2 of 0.3 mm x 0.05 mm.

On the non-conductive pad 6, at the ends, two connecting surfaces 7 are formed, on which six conductors 41, 42, 43, 44, 45, 46 are connected to one another. Conductors 41, 42, 43, 44, 45, 46 are connected at the ends of the core 1. , ie after the last thread 2, they are spaced apart from each other to create more space for the tip of the ultrasonic welder. The conductors 41, 42, 43, 44, 45, 46 are ultrasonically brazed, welded to the connecting surfaces 7.

At the same time, these attachment plates 7 are connected to a contact by which the entire radiator body is soldered to the substrate, in this example to the substrate of the removable microSD memory card 5. The emitter on the removable memory card 5 is positioned opposite to the card contact zone, in this example advantageously just in the part where the card has a small coarseness for easier removal of the card from the slot.

The core 1 with a cross-section of 0.8 mm x 0.6 mm has an equivalent radius of 0.391 mm. It is the radius at which the circular core has the same area of 0.48 mm ² as the cross-sectional area of the rectangular core of 0.8 mm x 0.6 mm. For 21 threads with a length of 9 mm, the effective width 3 of one thread 2 is about 0.428 mm. The ratio between the equivalent radius and the effective width is 1: 1.095, so the effective width of one thread corresponds to about 1.1 times the equivalent radius.

The advantage of the six parallel conductors 4 compared to the flat conductor is also its better conductivity at high frequencies. Due to the skin effect with a depth of p = 17pm / 14MHz, the conductive area of the six round conductors rr / 2 times larger than a flat conductor of the same size, resulting in lower losses. The radiator of this example has an inductance L = 1.3pH and a quality Q = 21 at a power load of 13dBm at a frequency of 14.4 MHz.

The antenna system consists of an antenna driver, a series parallel resonant system with a magnetic field emitter and a low noise high gain amplifier (limiter). The driver is designed in H bridge with output resistance Rout less than 4 Ω at bridge voltage supply Vcc = 2.7V. Since the switching time of MOSFET transistors is less than 1ns, it is necessary to filter higher harmonic switching products with the capacity of C3. The switching signals of the bridge H + and H- of the bridge are phase-shifted by 2.2ns, so that when switching them, both controlled branches are not switched on at the same time and thus the Vcc power supply is shorted to ground.

This construction achieves the effect of a "magnetic gun" with horizontal radiation at the ends of the core ferrite rod 1. The theory of the magnetic gun defined in this invention is that magnetic field lines cannot exit the ferrite rod of core 1 rather than at its ends because The electrically conductive materials of the conductors 4 with close mutual winding are impermeable to the magnetic field. And since magnetic field lines must always close each other, the only place where they can leave the radiator is the ends of the UV core, while winding cannot be done in such a way that there is no air gap between conductors 4 and therefore some of the field lines also leak between conductors. 4. The excellent radiation characteristics of the radiator located inside the metal shield are observed in Figure 15.

The radiator is located inside a mobile phone that has metal covers. This is shown in Figure 15 as a shielding cover 3, i. magnetic field flow obstruction. The magnetic field lines emanate from the small gaps between the covers out into the space where the NFC reader will be located.

The radiator disintegrates due to its location in different environments and if it is in close proximity to electrically conductive materials, the inductance of the radiator is reduced to 1μΗ. This feature is used to automatically control radiated power depending on the environment in which it is located. The radiator is tuned to 15MHz resonance when it is in a metal package (due to the environment the inductance of the antenna has decreased to 1μΗ). However, if placed outside the package, the inductance is increased to 1.3μΗ and the resonance is shifted to 12MHz. Since the radiator emits power at 14.4MHz, the maximum power is radiated only when its resonance is close to this value because its internal resistance is then the smallest, about 20 Ω. However, when placed under a plastic housing, the resonance will move down to 12MHz and the internal resistance at 14.4MHz will increase to 50 vz. Thanks to this arrangement, the radiator placed under the metal housing emits maximum power, while in the case under the plastic housing the radiated power automatically decreases, ensuring that in this case the receiving devices (POS terminals) are not awakened too high signal. This automatic tuning of the radiator power when the radiator impedance varies with the environment is shown in Figure 18.

Example 2

In this example according to Figures 5 and 6, a flat insulated conductor 4 is used whose cross-sectional height corresponds to approximately one eighth of the width of the conductor 4 in cross-section. The flat conductor 4 can be used in oval cross-sections of the core 7, where there is no risk of damage or breakage of the conductor 4 when it is wound onto the core 7 at small dimensions and small radii of curvature of the square core. In another embodiment, the conductor 4 on the core 1 may be formed by vapor deposition of a metal layer or other similar technology of applying a conductive path to the surface. A mask may be formed on the core 1 as a separation gap between the threads 2 at least at the thickness of the conductor 4. The mask in this case has the form of a helical strip with a width forming the interthread insulation 8. Then a metal layer is applied to form a flat, wide . Optionally applying insulation to the edge of the conductor 4 and then reapplying the strip of conductive layer that will overlap the inter-thread gap may result in a flattening of the edge of the flat conductor 4, thereby limiting the magnetic field leakage outside the core faces 1.

Example 3

In this example according to Figures 5 and 7, the flat insulated conductor 4 is guided over the edge of the adjacent thread 2, thereby creating a thread overlap in order to prevent the penetration of the magnetic field between the threads. The possibility of magnetic field leakage through a gap of twice the insulation thickness 8 of the conductor 4 remains.

Example 4

In this example of Figures 9 and 10, a combination of non-insulated conductors 42, 43, 44, 45, 46, and insulated conductors 41 and 47 is used. One thread 2 is formed by seven conductors 4 where both edge conductors of said thread 44 and 47 have insulation 8 to avoid inter-thread short-circuiting during tight winding. The non-insulated conductors 42, 43, 44, 45, 46 are located within the group. Since they do not have insulation 8, the formation of gaps for magnetic field leakage is reduced and at the same time there is no need to interconnect these conductors 42, 43, 44, 45, 46 electrically. Only conductors 41.42, 46 and 47 are therefore led to the connecting plate 7.

Example 5

In this example of Figure 11, a combination of one flat non-insulated conductor 42 and two insulated conductors 41, 43 with a classic circular cross-section is used to form one thread 2. This combination simplifies the manufacture of the radiator, since the suitable, available, low-thickness, flat conductors are not insulated. The edge conductors 41 and 43 form an inter-turn insulation, whereby they are conductively connected to each other on the connecting surface 7 and also to the flat conductor 42.

Example 6

In this example, the core 7 is in the form of a ferrite rod with a circular cross-section with a diameter of 0.8 mm and a length of 7 mm. The emitter has 17 coils 2, the effective coil width 2 is 0.41 mm. The ratio between the effective width of the thread 2 and the radius of the core 1 is 1.025. The permeability of the core i is chosen such that, given the dimensions of the emitter and the winding, the inductance is L = 750 nH.

Example 7

The conductor layer 4 is applied to the ferrite core 1 in the form of a ferrite rod having a rectangular cross-section. First, a helically guided mask is placed on the core 1, which will separate the threads 2 from each other. Subsequently, a metal layer is applied to the core I, whereby a winding with the required number of turns 2 is created due to the separating mask. The gap formed by the mask represents the inter-thread insulation. The end of the deposited metal layer on the sides of the core 1 is formed by connection plates 7, by which the whole element of the radiator is then fixed to the substrate.

In this example (but may also be in conjunction with other examples), the emitter is placed on the PCB of the mobile phone 10. The phone has covers with metal parts that constitute the shielding covers 3. By using the radiator of the present invention, the radiator can be placed in virtually any free space on the PCB board and there are no problems with poor magnetic field penetration from the mobile phone body.

Example 8

The radiator of Figure 23 is made similar to Examples 1 to 7. The mobile phone manufacturer designs new models such that the design of the PCB board 10 is not limited by the requirements for previously known types of NFC antennas. Different types and models of mobile phones provide one type of radiator directly on the PCB board 10.

Example 9

The radiator is located in the SIM card 9. The radiator core 1 is oriented and positioned differently in the different versions of Figures 19 to 22.

Example 10

The radiator of Figure 24 is housed in the mobile phone battery body. It is basically a rechargeable battery, which is commonly called a battery. Due to the small thickness of the core 1, the emitter is placed on the surface of a conventional battery under the last layer of the plastic battery shell.

Industrial usability

Industrial applicability is obvious. According to this solution, it is possible to industrially manufacture and use non-stationary magnetic field emitters as an antenna located directly on a removable memory card with high emissivity and small dimensions.

List of reference marks

1- core

2- thread

3 - magnetic field flow obstruction

4- wire

41,42, 43, 44, 45, 46, 47 to 4N - single thread wires

5-removable memory card

6- non-conductive pad

7-connection plate

8- Wire insulation

9- SIM card

10- PCB board

11- accumulator / battery w - effective thread width

PCB - Printed Circuit Board

NFC - Near Field Communication

POS - point of hall

RFID - Radio Frequency Identification SD - Secure Digital SIM - Subscriber Identity Module

Claims (24)

PATENT CLAIMS An unsteady magnetic field emitter in the function of a miniature antenna replacement in a mobile communication device, in particular a flat carrier antenna replacement, wherein the radiator has an elongated core (1) with a permeability greater than 1, a core (1) having at least and wherein the radiator forms an element for forming a contactless NFC or RFID communication channel, wherein the signal emitted from the radiator is received by a standard NFC or RFID receiving means, characterized in that the core (1) is at least partially ferrite, smaller in size the core cross-section (1) is less than 1 mm, the core length (1) is more than 7 times the smaller core cross-sectional dimension (1), the threads (2) are embedded in one or at most two layers; 2) are placed side by side on the core (1) to limit the magnetic field radiation from the core (1) outside its ends, the effective width w of one thread (2) being 0.25, and 1.75 times the radius of the core (1) with a circular cross section of the core (1) and corresponds to 0.25 to 1.75 times the radius of the equivalent for other forms of the core (1). The non-stationary magnetic field emitter according to claim 1, characterized in that the effective width w of one thread (2) corresponds to 0.85 to 1.15 times the radius of the core (1) at the circular cross-section of the core (1), or 1.15 times the equivalent radius for other core shapes (1). Non-stationary magnetic field emitter according to claim 1 or 2, characterized in that the cross-section of the core (1) is circular or elliptical in shape, or is at least partially rectangular, in particular square or rectangular, preferably with rounded corners, or has a cross-section formed by a combination of said shapes. Non-stationary magnetic field emitter according to any one of claims 1 to 3, characterized in that the core (1) has a straight rod shape. A non-stationary magnetic field emitter according to any one of claims 1 to 4, characterized in that the core (1) has a height of up to 1 mm, a width of up to 5 mm and a length of up to 15 mm. A non-stationary magnetic field emitter according to any one of claims 1 to 5, characterized in that the core (1) has a rectangular cross-section with a height of up to 0.6mm, a width of up to 1mm and a length of up to 11mm. A non-stationary magnetic field emitter according to any one of claims 1 to 6, characterized in that the winding conductor (4) is flat, preferably with a width exceeding twice the height of the conductor (4) in cross-section. The non-stationary magnetic field emitter according to claim 7, characterized in that the flat conductor (4) is overlapped along the edge by a conductor (4) of the adjacent thread, where the overlap is provided with insulation (8). A non-stationary magnetic field radiator according to any one of claims 1 to 8, characterized in that the winding comprises a plurality of parallel conductors (41 to 4N) forming a multistage thread (2) parallel to each other, these conductors (41 to 4N) of a single thread (4). they are electrically connected, preferably they are connected at the sides of the core (1). The non-stationary magnetic field emitter according to claim 9, characterized in that the multistage conductors (41 to 4N) are fed at the ends of the winding and connected to the connecting surfaces (7), where the conductors are spaced from one another. The non-stationary magnetic field emitter according to claim 9 or 10, characterized in that, in the case of at least four conductors (41 to 4N) of a single thread (2), only the outer conductors (41,4N) of one thread (2) are electrically insulated on their surface. ). A non-stationary magnetic field emitter of any one of claims 1 or 11, characterized in that the conductor (4) is formed by applying a metal layer to the surface of the core (1) with gaps between the turns (2). The transient magnetic field emitter according to any one of claims 1 to 12, characterized in that the permeability of the core (1) is selected such that at a given winding of the conductor (4) the emitter achieves an inductance of 600nH to 1200nH, preferably near 750nH. A stationary magnetic field emitter according to any one of claims 1 to 13, characterized in that it is tuned to a transmitting frequency such that it approaches, at its resonant frequency, the transmitting frequency when the emitter is positioned near the shielding cover (3), wherein the proximity of the shielding cover (3). 3) reduces the inductance of the radiator and where, after removing the effect of the shielding cover (3), the inductance of the radiator increases, the internal resistance increases and the resonant frequency decreases and moves away from the transmitting frequency. The non-stationary magnetic field emitter according to claim 14, located in a particular environment, characterized in that the frequency and / or inductance and / or internal resistance is set to the maximum transmitting power at the most unfavorable shielding, where reducing the shielding rate the same input excitation in that the environmental shielding affects the frequency and / or inductance and / or internal resistance of the emitter, and even at zero shielding, the emitter transmitting power is higher than the minimum receiving power by standard NFC or RFID receiving means. Non-stationary magnetic field emitter according to any one of claims 1 to 15, characterized in that the core (1) is formed by a ferrite rod disposed on a non-conductive pad (6), the non-conductive pad (6) has a width corresponding to the width of the core (1). (6) has a length equal to or exceeding the length of the core (1), the conductors (4) of the threads (4) being mechanically wound through the ferrite rod and also through the non-conductive pad (6), thereby winding the conductor (4) connects the core (1) the non-conductive washer (6) has connecting surfaces (7) on the sides of the core (1) for connecting the winding wires (4) and connecting the radiator to the body of the guest device. Non-stationary magnetic field emitter according to claim 16, characterized in that the non-conductive pad (6) is made of dielectric material with a thickness less than one-eighth of the height of the core (1). A non-stationary magnetic field radiator according to any one of claims 1 to 17, characterized in that the winding of the threads (2) is covered by a conductive shielding cover which is connected to ground. 19. A stationary magnetic field emitter according to any one of claims 1 to 18, wherein the emitter is disposed on a substrate of the removable memory card (5). The position of the non-stationary magnetic field emitter according to claim 19, characterized in that the axis of the emitter core (1) is oriented predominantly parallel to the surface of the removable card body (5) and the emitter is located at the edge of the removable memory card body (5) outside the contact zone. interface, 5 preferably along the edge opposite the edge with the contact interface zone of the removable memory card (5). Location of a non-stationary magnetic field radiator according to any one of claims 1 to 18, characterized in that the radiator is located on a PCB board (10) of a mobile communication device, in particular a mobile phone. 10 22. The position of the non-stationary magnetic field emitter according to claim 21, characterized in that the axis of the emitter core (1) is oriented predominantly parallel to the prevailing outer surface of the body of the mobile communication device. 23. The positioning of the non-stationary magnetic field emitter according to any one 15. A method according to any one of claims 1 to 18, wherein the radiator is disposed on SIM card (9). 24. The location of a non-stationary magnetic field emitter according to any one of claims 1 to 18, wherein the emitter is disposed within the body of the removable mobile phone battery (11).