Amplified radio frequency identification tag
Patent Information
- Application Number
- NL2039060
- Authority / Receiving Office
- NL · NL
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-11-12
- Publication Date
- 2026-06-09
- Estimated Expiration
- 2044-11-11
Smart Images
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Abstract
Description
l P136621NL00 Title: Amplified radio frequency identification tag Field ofthe invention The present invention is directed at a radio frequency identification tag. Background Radio frequency identification (RFID) tags are widely used on farms to track and monitor animals. These tags enable farmers to quickly identify individual animals, monitor their movements, and gather data on their health. Such tags thereby contribute to farm efficiency. Passive RFID tags, which do not have an internal power source, rely on energy from a nearby RFID reader to transmit data, making them suitable for short-range applications. Active RFID tags, which are provided with their own power source, can transmit signals over distances ranging from several meters to a few hundred meters, depending on the environment and the specific technology used. For larger farms, where animals may roam over extensive areas, these ranges are quite limited. In general, transmitting signals across large distances requires more power, which will rapidly drain the batteries of active RFID tags, leading to shorter life span and thus frequent replacements, thereby increasing maintenance costs and decreasing environmental durability. Batteries with increased capacitymaybe used, but these are larger and heavier and therefore are often not desired. An alternative communication technology is long-range (LoRa) communication. Unlike RFID, LoRa uses a chirped spread spectrum modulation technique to achieve high transmission ranges, but the trade-off for this capability is lower data transfer rates. Additionally, LoRa operates on shared frequency bands and can therefore face issues with interference and limited network capacity when many devices attempt to communicate simultaneously within the same frequency band. Summary ofthe invention It is an object ofthe present invention to provide an active radio frequency identification tag that overcomes the abovementioned drawbacks, and which enables to provide amaximum transmission range at highly efficient power usage. To this end, there is provided herewith a radio frequency identification tag for being worn by an animal, comprising apower supply such that the tag is an active radio frequency identification tag, wherein the tag further comprises a printed circuit board including a controller and a data communication circuit, the data communication circuit including a transceiver, wherein the transceiver is configured for transmitting an electronic data communication signal via an antenna, wherein the printed circuit board further comprises a power amplifier circuit for amplifying the electronic data communication signal for transmission thereof, the power amplifier circuit therefore having a signal input path for receiving the electronic data communication signal and a power input path, wherein the printed circuit board further comprises a capacitor, wherein the capacitor is configured for storing electrical energy from the power supply and for releasing, during a predefined period, the stored electrical energy such as to feed a power input signal to the power input path for powering the power amplifier circuit, such as to enable the power amplifier circuit to amplify the electronic data communication signal and to provide, via a signal output path, the amplified electronic data communication signal to the antenna. The radio frequency identification tag in accordance with the invention comprises a capacitor that continuously draws a small current from the power supply ofthe tag. The electrical energy from this current is stored in the capacitor. During a predefined period, the stored electrical energy is then discharged and provided to the power amplifier circuit, allowing the power amplifier circuit to amplify the electronic data communication signal obtained from the transceiver. This advantageously enables the tag in accordance with the invention to transmit electronic data communication signals over very large distances. These distances can extend up to a kilometer, and in some cases, reach as far as four kilometers. Furthermore, the power amplifier circuit is poweredby a small current on the order of 100 nA, drawnby the capacitor from the power supply. The small current may for example be around 100 nA, or higher such as a few hundred nanoamperes, as long as it is larger than the leaking current ofthe capacitor. Since it is gradually charged by this current from the power supply, the capacitor delivers the peak power required for the amplifier upon transmission of a signal using the charge it has been collecting from the small current provided by the power supply, without at thatmoment requiring additional power from the power supply. Therefore, the radio frequency identification tag in accordance with the invention advantageously is able to transmit data communication signals over large distances without the need to use a large battery. The radio frequency identification tag in accordance with the invention is able to function using a regular battery without a significant cost to the battery life, making the tag highly efficient in terms ofpower usage. Furthermore, ordinarily a transceiver trying to transmit a signal over larger distances would need to draw higher currents from a power supply, leading to greater stress on the internal components ofthe power supply. Because the peak power needed to power the power amplifier circuit is providedby the capacitor, the invention advantageously prevents the power supply ofthe tag from being overloadedby the power demand ofthe tagwhen a signal is to be transmitted over very large distances. The invention therefore is able to greatly increase the transmission range ofthe tag in a power efficient manner, while at the same time maintaining the lifespan ofthe tags power supply. In accordance with some embodiments ofthe invention, the transceiver is configured for transmitting the electronic data communication signal during a transmission period, wherein the capacitor is configured for releasing stored electrical energy during the transmission period. In these embodiments, the tag transmits a signal only during the transmission period and does not transmit a signal during a non-transmission period. During non-transmission periods, the tag may for example continuously collect and store health-related data or location data from sensors. Apacket ofsensor datamay then be transmitted in combination with identification data during a transmission period. Alternatively, the tagmay be idle during the non-transmission period. Animals wearing the tag will often engage in activities for prolonged periods oftime and will often remain around the same location for prolonged periods oftime. As such, it will typically not be necessary for the tag to transmit identification data or position data continuously or frequently in order to effectively monitor the animals. By limiting the transmission of electronic communication signals to a transmission period, rather than transmitting a data communication signal continuously, the power consumption of the radio frequency identification tag is significantly reduced without sacrificing the effectiveness with which animals wearing the tag are monitored. Also, this allows the charging ofthe capacitor inbetween the transmission periods, to aid in diminishing or preventing peak power consumption in order to extend the battery life. This advantage is further enhanced the shorter the transmission period is relative to the non-transmission period. These embodiments therefore further enhance battery life and lengthen the life span ofthe power supply, thus further reducing the frequency of the need for replacement. In these embodiments, typically a portion ofthe electrical energy stored in the capacitor is used to power the power amplifier circuit, leaving a remaining portion required to keep the tag operational. In some embodiments, powering the power amplifier circuit using all of the electrical energy stored in the capacitormay result in a reboot ofthe controller ofthe tag. However, the skilled person will appreciate that in some implementations all ofthe stored electrical energymay be used to power the power amplifier circuit without such a resulting reboot ofthe tags operation. In accordance with some embodiments ofthe invention, the transceiver is configured for receiving or transmitting the electronic data communication signal at a frequency between 0.4 GHZ and 4 GHZ, preferablybetween 2 GHZ and 8 GHZ, more preferably between 2.4 GHZ and 2.5 GHZ. Because the wavelength of transmitted signals is inversely proportional to the frequency, this frequency range allows for a conveniently sized antenna to be used in the tag, less than 10 cm in length. This makes this frequency range especially suitable for being used in active RFID ear tags to be worn by an animal, since a lower frequency range, such as around 125 kHz, would need a significantly larger antenna, while higher frequencies would introduce challenges to the signal quality due to obstacles in between the tag and a reader. Additionally, the frequencies used in these embodiments allow more data to be transmitted in a given amount oftime than other frequencies typically used in RFID technology, such as 125 kHz. This is because these ranges can offer wider bandwidths, enabling more information to be encoded in a signal. These embodiments therefore increase the amount of data that can be transmitted over large distances using the tag. In accordance with some embodiments ofthe invention, the electronic data communications signal is an unbalanced signal, wherein the antenna is a dipole antenna connected to the transceiver via a balun, the balun being configured to convert between an unbalanced signal ofthe transceiver and a balanced signal of the dipole antenna. The balun can convertbetween the unbalanced and balanced signals with minimal power loss, while also maintaining signal integrityby preventing effects such as interference effects andcommon mode currents via impedance matching. The signal quality ofthe tag is thereby improved because it is less distortedby the electronics on the tag. This also further improves the transmission range ofthe tag, because the clearer signal, being less distortedby the electronics on the tag, will remain at a detectable power level over larger distances. Moreover, dipole antennas can have a more focused radiation pattern than monopole antennas, and thus have a higher gain. Generally a dipole antenna has a toroidally shaped radiation pattern, with most ofthe radiation being concentrated in the directions perpendicular to the axis ofthe dipole. Although the radiation pattern of a monopole antenna would look similar, upward reections from the ground plane would reduce the effective radiation from the monopole antenna. As a consequence, signals can be transmitted across longer distances using dipole antennas than using monopole antennas. These embodiments therefore further enhance the transmission range ofthe tag while maintaining the power usage efficiency. In accordance with some embodiments ofthe invention, the antenna is arranged along an outer edge ofthe printed circuit board. Antennas placed between components or surroundedby other elements ofthe printed circuit board may have a disrupted radiation pattern, with portions ofthe emitted signal being blocked or reected by nearby components. Arrangement ofthe antenna along the outer edge ofthe printed circuit board helps create a uniform radiation pattern, since the antenna in that case has a clearer path to radiate the signal into free space. By minimizing obstruction ofthe signal by other components on the printed circuit board, this can enhance coverage and improve the likelihood ofreaching large transmission distances. It also helps separate the dipole antenna from the electronic components on the printed circuit board, reducing the risk ofcoupling of noise and interference components into the signal from active components on the printed circuit board. Ifthe antenna were arranged through the printed circuit board for example, these signal components could distort the signal and reduce its quality and range. Consequently, these embodiments further improve the transmission performance of the tag by providing a more consistent and a clearer signal. In accordance with some embodiments ofthe invention, the tag further comprises an attachment member for attaching the tag to the animal. The attachment member enables the tag to be attached to an animal, making the tag applicable in farm settings, where farm animals can roam large areas and reach large distances from a base station. The tagmay for example be an ear tag or a leg tag, or may be attached to another part ofthe animals body. The tagmay house various sensors that collect data on the animal's vital signs, movements, and environmental conditions. For example, accelerometers in an ear tagmay be used to monitor movements ofthe animals head in order to determine activities such as grazing from the animal. When an animal grazes, it typically exhibits repetitive head movements as it lowers its head to the ground, moves forward, and raises its head again. These motions produce a distinct pattern in the accelerometer data, which can be identified and associated with the behavior. In alternative embodiments, the tagmay solely be used for positioning or identification purposes without the inclusion ofother sensors. The tagmay be used for a range of applications depending on the specific needs ofthe user. In accordance with some embodiments ofthe invention, the attachment member is one of a group comprising: a reception opening configured for receiving a pin of a complementary part for enabling piercing ofthe tag, a clamp, a magnetic member, and an adhesive part. In some embodiments, the tagmay be an ear tag and the attachment member may advantageously be formed by a reception opening for receiving a pin. Such an attachmentmember ofan ear tag creates a secure attachment that minimizes the risk ofthe tag falling offthe animals ear due to movement or external forces. The complementary shapes in other words reduce the risk of accidental detachment. In alternative embodiments, the tagmay instead be a neck tag and the attachment member may for example be formedby a clamp, which may for example include an adjustable strap. In this alternative embodiment, the tag can be clamped around the neck ofthe animal securely and the risk of accidental detachment ofthe tag from the animal is thereby similarly reduced. An adjustable strap then further optimizes the fit ofthe tag with the body part ofthe animal to which the tag is attached, further reducing the risk of accidental detachment. Each type of attachment member is suitable for being used with the tag according to the invention. In accordance with some embodiments ofthe invention, the tag is an ear tag and the attachmentmember is positioned at a first offset from the printed circuit board, such that in use, the printed circuit board and the antenna are arrangedbelow the attachment member. Having the printed circuitboard and antenna hangbelow the attachmentmember ensures that the tag remains oriented in a consistent, vertical position, because in this configuration the center ofmass will also be positioned at an offset from the attachment member. With a radiation pattern ofthe antenna being oriented perpendicular to the antennas orientation, which would be arranged parallel to the printed circuit board, this vertical orientation ofthe tag helps optimize the antenna's radiation pattern for better performance in terms oftransmission range. In particular, the vertical orientation of the tag results in a horizontal orientation ofthe antennas radiation pattern, which is typically the relevant plane for reaching high transmission distances, as the antenna of a reader or base station will often be located at a large horizontal distance from the tag but at a relatively small vertical distance from the tag. Moreover, this configuration ofthe tag will typically result in the tag hanging below the ear ofan animal. This is advantageous for the signal quality, because obstructions ofthe signal causedby the presence ofthe animals ear in the radiation field ofthe tag are minimized. Since most ofthe weight in the tag will be positioned near the printed circuit board, this positioning of the printed circuit board and the antenna relative to the attachment member is achieved in use by gravity. In accordance with some embodiments ofthe invention, the tag further comprises a housing comprising the printed circuit board, the housing comprising a back side that in use faces an ear ofthe animal to which the tag is attached, wherein the power supply is arranged in the housing between the printed circuit board and the back side, such as to be arrangedbetween the printed circuit board and the ear in use. This configuration maximizes the distance between the printed circuit board and antenna, and the ear ofthe animal. An ear of an animal wearing the tag, which is in close proximity to the antenna, will reect a significant portion of the radiation from the antenna. This adversely affects the strength and clarity of the emitted fieldbeyond the animals ear and thereby reduces the transmission range in that direction. Proximity ofthe antenna to the ear also causes the resonance ofthe antenna to shift, which adversely affects the signal quality and range ofsignals transmittedby the tag. The presence ofthe power supply ofthe tag between the antenna and the ear of the animal minimizes the effects of signal obstruction by the ear and thereby further improves the transmission range ofthe tag. Furthermore, the housing serves to protect the tag from collisions with other objects, and from harsh weather conditions, which helps maintain the lifetime of the tag. In accordance with some embodiments ofthe invention, the dipole antenna comprises two antenna arms, wherein the printed circuit board is arranged vertically in the tag in use, such that the antenna arms are arranged in a vertical plane. In these embodiments, one of the antenna arms will be arranged above the other antenna arm within the vertical plane. As a result, the total dipole of the tag, formedby the two antenna arms, will be oriented vertically. Because the dipole antenna is oriented vertically, the radiation pattern will be oriented in a horizontal plane. Specifically, since the antenna is a dipole antenna, the radiation pattern will have a toroidal shape in which the radiation is concentrated in the horizontal directions and at aminimum level in the vertical directions. This advantageously maximizes the horizontal transmission range ofthe tag. In accordance with some embodiments ofthe invention, the dipole antenna comprises two antenna arms, wherein the antenna arms each follow a curved path along the outer edge ofthe printed circuit board. In these embodiments, the electronics on the printed circuit board are positionedbetween the antenna arms, inward from the curved paths followedby the antenna arms. The outward radiation ofthe dipole antenna can then be transmitted into free space without obstruction by the electronic components on the printed circuit board, and without distortion by noise or interference signal components from active components on the printed circuit board. These embodiments therefore minimize signal interference ofthe electronic data communication signal by the electronics and helps maximize the transmission range ofthe tag. In alternative embodiments, the antenna may be a monopole antenna that may be formedby a single antenna arm. This allows for a cheaper, more simple and more compact design ofthe tag, at the sacrifice of a degree oftransmission range. Use of monopole antennas can reduce the amount ofrequired material for manufacturing the tag and reduces its weight. This makes the tag more comfortable for the animal wearing it. In accordance with some embodiments ofthe invention, the curved path is one of a group comprising: circular paths, elliptical paths, parabolic paths and hyperbolic paths. Any one ofthese paths is suitable for creating a radiation pattern that is oriented substantially omnidirectionally in the plane perpendicular to the axis around these paths are formed. In use, the transmission distance ofthe tag can therefore be maximized along this plane. The type ofcurved path will however still affect the directions within the horizontal plane in which the radiation will be concentrated. For example, circular paths will result in the most omnidirectionally uniform radiation pattern, as the path has only one radius ofcurvature. Ifthe arms of the dipole follow elliptical paths, the curves will have two radii ofcurvature, which will introduce asymmetry in the radiation pattern ofthe antenna. This will result in a radiation pattern that is compressed along the major axis ofthe ellipse and more elongated along the minor axis. Parabolic paths on the other hand will cause a directional shift in the radiation pattern, concentrating the radiation in the direction ofthe open side ofthe parabola. Hyperbolic paths ofthe antenna can result in more focused directional lobes ofthe radiation pattern directed along the asymptotes ofthe hyperbola. The curvatures ofthe elliptical paths, parabolic paths and hyperbolic paths can be tuned to make these effects on the radiation pattern more or less pronounced, in accordance with the specific requirements of a user. An omnidirectionally uniform radiation pattern would likely be most versatile and simplest to implement, as the tag would have an equally large transmission range in all directions ofthe horizontal plane. However, a more directionally focused radiation pattern can provide additional information about the animal wearing the tag. For example, in anRFID system with multiple receiving antennae scattered across a large area, information about the direction in which an animal is oriented can be gathered using more directionally focused radiation patterns based on which antenna receives the strongest signal from the tag. In accordance with some embodiments ofthe invention, the power supply includes at least one of a battery and a solar panel.Abattery in the tag allows the tag to store large amounts of electrical energy to be used to power every electronic component ofthe tag. Embodiments that feature a solar panel have an advantage in that the solar panel is able to continuously draw energy from sunlight. This solar energy can then be stored in a battery ofthe tag, or may be stored in the capacitor of the tag. By aiding in providing electrical energy to the battery, a solar panel can therefore lengthen the battery life ofthe tag. Although in some embodiments a solar panelmay be an auxiliary or secondary source of electrical energy for the tag, or for specific parts thereofsuch as the capacitor, in other embodiments a solar panel may act as a primary source of electrical energy for the tag. By aiding in the provision of electrical energy to the tag, the solar panel can further improve the power usage efficiency of the tag and provide a more environmentally friendly tag. The presence of a solar panel may also reduce the required size of a battery, potentially reducing the overall weight ofthe tag, making it more comfortable to wear for an animal. In accordance with some embodiments ofthe invention, the tag is at least one of a group comprising: an ear tag, a stomach bolus, a leg tag, a neck tag or a tail tag. Depending on the specific requirements ofthe user, different implementations ofthe tagmay be more advantageous. For example, implementing the tag as a stomach bolus may be preferred ifthe tag is to detect certain vital data from the stomach of the animal, because ifthe tag is located in the stomach ofthe animal, itmay be more capable of acquiring these vital data than ifthe tag were applied on the exterior ofthe animal. However, if the tag is only to be used for positioning purposes and the transmission range ofthe tag should be maximized, it would be more beneficial to implement the tag such that itmay be attached externally to the animal, such as an ear tag, a leg tag, a neck tag or a tail tag. This also applies for other kinds of data, such as movement, orientation, and activity data. Attaching the tag to the ear of an animal for example allows to detect movements ofthe head ofthe animal, which can be used to determine when the animal is engaged in certain activities such as grazing. In accordance with some embodiments ofthe invention, the transceiver is further configured for receiving an electronic data communication signal via the antenna. Advantageously, these tags are able to receive electronic data communication signals transmittedby other tags. These received signals may then for example be retransmitted for being receivedby another tag or by a receiving antenna, such as an antenna of a base station. By passing the signals transmitted by a tag to an endpoint via various transceivers, a receiving feature ofthe tag greatly improves the transmission range ofthe tag. As a concrete example, ifeach tag has a transmission range oftwo kilometers, and a signal can be receivedby three tags before reaching an endpoint, the total potential transmission range is quadrupled to eight kilometers. Embodiments in which the tags are also configured for receiving signals also allow a network oftags to expand in size and scope with a reduced need for dedicated receiving antenna infrastructure. This is because the tags themselves can partially fulfill the role ofthe dedicated antennae. Brief description ofthe drawings The invention will further be elucidatedby description ofsome specific embodiments thereof, making reference to the attached drawings. The detailed description provides examples ofpossible implementations of the invention, but is not to be regarded as describing the only embodiments falling under the scope. The scope ofthe invention is defined in the claims, and the description is to be regarded as illustrative without being restrictive on the invention. In the drawings: Figures 1A schematically illustrates a radio frequency identification tag in accordance with an embodiment ofthe invention, from a sectional perspective view. Figure 1B schematically illustrates the radio frequency identification tag in accordance with an embodiment ofthe invention, from a front sectional view, relative to the tag orientation in use. Figure 1C schematically illustrates an orientation of a tag according to an embodiment ofthe invention, in use, and its corresponding radiation pattern. Figure 2 schematically illustrates a period ofoperation of a radio frequency tag in accordance with an embodiment ofthe invention. Figure 3A provides a schematic overview ofthe electronics included in a radio frequency identification tag in accordance with an embodiment ofthe invention. Figure 3B schematically illustrates an equivalent circuit of a power supply, a capacitor and a power amplifier circuit included on a printed circuit board of an embodiment ofthe invention. Detailed description Figure 1A schematically illustrates a radio frequency identification tag 1 in accordance with an embodiment ofthe invention. The tag 1 comprises a housing formedby front housing part 2a andback housing part 2b, which houses a power supply 8 and a printed circuitboard 4. The housing may be formed differently in alternative embodiments. For example, the tag may comprise a moulded housing that is a single piece ofmaterial. The housing provides the tag with protection against collisions between the tag and other objects, and against harsh weather conditions. As further illustrated in figure 1B, the printed circuit board 4 in this embodiment comprises a controller 5 and further comprises a data communication circuit 6 including a transceiver 61 and is connected to antenna arms 9-1 and 9-2 of an antenna via a balun 10. The printed circuit board 4 further comprises a capacitor 7 and a power amplifier circuit 8 for amplifying an electronic data communication signal. The tag 1 may further comprise a sensor (not shown), such as accelerometers or sensors for collecting health-related data. The power supply 8 continuously supplies the circuitry in the printed circuit board 4 with electrical energy, including the capacitor 7, which only draws a small current thatmay be on the order of 100 nA, such that the capacitor is charged graduallyby this current. The capacitor 7 therefore is chosen to have very little leak currents, such that on net the capacitor 7 is able to accumulate electrical energy from the power supply 3. Once the capacitor 7 has accumulated enough charge, it may release at least some of its electrical energy to the power amplifier circuit 8 by providing an activation current thereto. This may occur during a predefined transmission period, and the charging time of the capacitor would be chosen in accordance with such a transmission period, such that the capacitor 7 is always sufficiently charged for providing the power amplifier circuit with an activation current in order to amplify a signal to be transmitted. The power amplifier circuit 8 at the moment a signal is to be transmitted thus receives both the activation current from the capacitor 7, and an electronic data communication signal from the data communication circuit 6. The power amplifier circuit 8 amplifies the electronic data communication signal and provides an amplified electronic data communication signal to the antenna, which can therefore be transmitted over larger distances. Because the power amplifier circuit 8 is powered by a current from the capacitor 7, which is gradually chargedby the power supply 3, the tag 1 advantageously is able to achieve a high transmission range up to and over a kilometer without the need for an additional power supply for powering the power amplifier circuit 8. Furthermore, the power supply 3 may be a battery, but the tag 1 may alternatively be provided with a solar panel or other power source. In this embodiment, the antenna is a dipole antenna comprising antenna arms 9-1 and 9-2. The dipole antenna is connected to the transceiver 61 via the balun 10, as the electronic data communication signal while carried in the circuitry ofthe printed circuit boardmay be an unbalanced signal, whereas the dipole antenna transmits a balanced signal. Conversionbetween the two signals would therefore be necessary.Abalun is needed in the tag only ifthere is a mismatchbetween the type ofsignal carried on the printed circuit board and the type of signal emittedby the antenna. In alternative embodiments, the electronic data communication signalmay be a balanced signal, thus removing the need for a balun 10 to convert between balanced and unbalanced signals. Dipole antennas, which emit balanced signals can advantageously have a more focused radiation pattern than monopole antennas, and thus have a higher gain, allowing them to be transmitted over larger distances. However, in alternative embodiments, the antennamay be a monopole antenna carrying an unbalanced signal. Such embodiments similarly lack the need for abalun ifthe transceiver 61 provides an unbalanced electronic data communication signal. The antennamay be arranged along the outer edge of the printed circuit board 4. For example, in this embodiment both antenna arms 9-1 and 9-2 follow a curved path along the outer edge ofthe printed circuit board. When the antenna runs along the outer edge ofthe printed circuit board, the antenna is able to radiate signals outward into free space without the signal being obstructed by components ofthe printed circuit board. The radiation pattern ofthe transmitted signal is thereby made more uniform and because it radiates unobstructed, the signal is able to travel larger distances. This arrangement ofthe antenna therefore helps the tag 1 reach higher transmission distances. Moreover, the radiation pattern is less likely to be distortedby the presence ofthe active electronics in the tag 1. Such electronics can generate noise or interference to the signal which can reduce the signals clarity. By preventing these disturbances in the signals, the signal quality is also improved. The tag 1 further comprises an attachmentmember 11 for attachment of the tag 1 to an animal. In this embodiment, the attachmentmember 11 is a reception opening for receiving a pin of a complementary part for enabling piercing of the tag. In this way, the tag 1 may be used as an ear tag. This is an advantageous spot for attaching the tag to an animal, because it also allows for example the use of accelerometers in the tag for monitoring head movements ofthe animal. Analysis ofpatterns in these movement data can provide valuable information about the animals activities or health. In alternative embodiments, attachment ofthe tag to the animalmay be achieved by the use of a clamp, a magnetic member, or an adhesive part. Furthermore, the tag 1 may instead be a stomach bolus, a neck tag or a tail tag. The specific implementation ofthe tag will varybased on the specific purposes for which the tag is to be used. The attachment member 1 1 is positioned in the tag 1 at an offset from the printed circuit board 4, such that in use, the printed circuit board 4 and the antenna are arranged below the attachment member. The attachmentmember 11 may be a reception opening shaped for cooperating with a complementarily shaped pin for attaching the tag to an ear of an animal. The attachmentmember may be at an offset from the printed circuit board, and more particularly from the antenna. This offset may be sufficiently large, such that the antenna is able to radiate electromagnetic waves into free space in such a way that the radiation pattern of the electronic data communication signal transmittedby the transceiver 61 is unobstructedby the ear, or in alternative embodiments where the tag is attached to a different part ofthe animal, by the other part ofthe animal to which the tag is attached. This helps increase the transmission range that can be reachedby the tag 1. To further enhance this advantage, the power supply 3 may be positioned in the housing 2 in between the printed circuit board 4 and the animal ear. This maximizes the distance between the antenna arms 9-1 and 9-2 and the animal ear, thereby minimizing distortions in the radiation pattern causedby the presence of the animal ear. Since a major part ofthe weight of the tag 1 may be distributed near the printed circuit board 4 and the antenna, at an offset from the attachment member 1 1, the printed circuit board 4 and the antenna in use may be pulledby gravity such as to be arranged in a vertical plane. This advantageously causes the radiation pattern ofthe signal transmitted from the antenna arms 9-1 and 9-2 to be oriented substantially horizontally. This is further illustratedby figure 1C, which shows a printed circuitboard 4 ofthe tag and antenna arms 9-1 and 9-2 arranged along the outer circumference ofthe printed circuit board. The antenna arms are shown suspended in an orientation the tag would assume in use. Antenna arm 9-1 is arranged along the upper side ofthe printed circuit board 4 and antenna arm 9-2 is arranged along the lower side. The resulting dipole formedby these two arms is therefore oriented vertically. Because in this embodiment the dipole formed by the antenna is oriented in a vertical plane (in this case the xz plane), the toroidally shaped radiation pattern is oriented in a horizontal plane (in this case the xy plane). The tag therefore radiates very little in vertical directions and radiates most of its energy in horizontal directions. The largest distances that can be reachedby the electronic data communication signal transmittedby the antennamay therefore also be substantially horizontal. This increases the distance from the tag 1 at which a base station or reader may be located while being able to detect the signal transmitted from the tag 1. Although in this figure the ends ofthe antenna arms are shown visible to the viewer, the antenna arms may also be rotated 180 degrees; this will still result in a toroidally shaped radiation pattern that is oriented in the horizontal plane. Figure 2 schematically illustrates a period ofoperationT of a radio frequency identification tag in accordance with an embodiment ofthe invention. The periodTmay be divided such that in use, the tag 1 may have predefined non- transmission periods 12, in which the transceiver 61 does not transmit an electronic data communication signal, and predefined transmission periods 13, in which the transceiver 61 transmits an electronic data communication signal. At the beginning of a period t = 0, the capacitor 7 continuouslymay draw a small current from the power supply 8, gradually charging the capacitor 7. Optionally, the tag 1 may be sensing and storing measurement data from an optional sensor during the non-transmission period 12. Moreover, in some embodiments power usage ofthe tag 1 may be further improvedby confining the collection ofsensor data to the transmission period 13. Once the predefined transmission period 13 starts at t = t0, the transceiver will transmit the signal to be emitted via the antenna after it has been amplifiedby the power amplifier circuit, which at thatmoment draws electrical energy from the capacitor 7 which it has accumulated during the non- transmission period 12. The power amplifier circuit 8 can then amplify an electronic data communication signal from the data communication circuit 6, providing an amplified signal for being transmittedby the antenna. The electronic data communication signal, being an amplified signal by the power amplifier circuit 8, can be transmitted over large distances over a kilometer, up to four kilometers. Because the electronic data communication signal is only transmitted during the predefined transmission period 13, the required power for transmission of the signal is significantly reduced. Furthermore, because the power amplifier circuit 8 is poweredby an activation current from the capacitor 7, which in turn gradually stores electrical energy received from the power supply 3, the tag according to the invention is able to reach transmission distances of over a kilometer without the need for an additional power supply and is therefore highly energy efficient. Figure 3A schematically illustrates electronics included in a radio frequency identification tag in accordance with an embodiment ofthe invention. The power supply 3 provides electrical energy to the electronic components ofthe tag, including the controller 5 and capacitor 7. The controller is configured for controlling the various parts and components of the circuitry in the tag. In this figure, the controller 5 is shown only to be connected to the data communication circuit 6 for simplicity. At appropriate moments, the controller 5 provides the components with instructions. The controller 5 further collects data from any sensors that are present in the tag and stores them until they are to be transmitted by the transceiver 61. In some embodiments ofthe invention, the tag is also configured for receiving an electronic data communication signal. Signals received by the tag, such as signals transmittedby other tags within the transmission range of the tag, may also be storedby the controller 5. Moreover, the controller 5 provides the transceiver 61 with the electronic data communication signal, which is the encoded signal to be transmitted, including the identification information ofthe tag. The controller therefore enables the identification functionality of the tag. When the transceiver 61 is instructedby the controller 5 to transmit an electronic data communication signal, the transceiver 61 receives the signal to be transmitted from the controller and sends the signal to the antenna 9 after it is amplifiedby the power amplifier circuit 8, which at that moment draws an activation current 81 it needs in order to be able to amplify the electronic data communication signal from the capacitor 7. The amplified electronic data communication signal is then provided to the antenna 9 to be transmitted. Figure 8B schematically illustrates an equivalent circuit ofthe power supply 8, the capacitor 7 and the power amplifier circuit 8 in a tag according to an embodiment ofthe invention. The power supply 8 is provided in this embodiment as aDC battery, but in alternative embodiments may for example be formedby a solar panel on the exterior ofthe tag. The power supply 8, the capacitor 7 and the power amplifier circuit 8 are all electrically connected in parallel inside the circuitry ofthe tag. The power supply 8 continuously feeds a small current, on the order of 100 nA, to the capacitor 7 and thereby gradually charges the capacitor 7. Once the capacitor is fully charged, the charge stored in the capacitor 7 will remain steady as long as the voltage across the capacitor 7 remains equal to the voltage across the power supply 3. The capacitor 7 is chosen to have very little leaking current, so that on net the capacitor 7 is able to accumulate charge from the small current providedby the power supply 3 and so that the stored charge can be maintained in the capacitor 7 once fully charged. The rest ofthe electronics ofthe tag (not shown) receive the vast majority ofthe current providedby the power supply 3. Once a signal is ready to be sent, the power amplifier circuit 8 will draw an activation current. This increased energy demand will then be metby the capacitor 7. The charge stored in the capacitor 7 is released to the power input path of the power amplifier circuit 8 for enabling the power amplifier circuit 8 to amplify an electronic data communication signal and provide the amplified electronic data communication signal to the antenna. Through the use ofthe capacitor 7, the tag therefore is able to transmit an amplified signal across large distances without the need for an abnormally large or additional power supply. The present invention has been described in terms ofsome specific embodiments thereof. It will be appreciated that the embodiments shown in the drawings and described herein are intended for illustrated purposes only and are not by any manner or means intended to be restrictive on the invention. It is believed that the operation and construction ofthe present invention will be apparent from the foregoing description and drawings appended thereto. It will be clear to the skilled person that the invention is not limited to any embodiment herein described and that modifications are possible which should be considered within the scope ofthe appended claims. Also kinematic inversions are considered inherently disclosed and to be within the scope ofthe invention. Moreover, any of the components and elements ofthe various embodiments disclosedmay be combined or may be incorporated in other embodiments where considered necessary, desired or preferred, without departing from the scope ofthe invention as defined in the claims. In the claims, any reference signs shall not be construed as limiting the claim. The term 'comprising' and including when used in this description or the appended claims should not be construed in an exclusive or exhaustive sense but rather in an inclusive sense. Thus the expression comprising as used herein does not exclude the presence ofother elements or steps in addition to those listed in any claim. Furthermore, the words a and an shall not be construed as limited to only one, but instead are used to mean at least one, and do not exclude a plurality. Features that are not specifically or explicitly described or claimedmay be additionally included in the structure ofthe invention within its scope. Any of the claimed or disclosed devices or portions thereofmay be combined together or separated into further portions unless specifically stated otherwise, without departing from the claimed invention. Expressions such as: "means for should be read as: "component configured for ..." or "member constructed to ..." and should be construed to include equivalents for the structures disclosed. The use of ressions like: "critical", "preferred", "especially preferred" etc. is not intended to t the invention. Additions, deletions, and modifications within the purview of skilled personmay generally be made without departing from the spirit and pe ofthe invention, as is determinedby the claims. The inventionmay be cticed otherwise then as specifically described herein, and is only limitedby the ended claims. P136621NL00
Claims
1. Radio frequency identification tag to be worn by an animal, comprising a power supply, such that the label a active radio frequency is an identification label, where the label furthermore comprises a printed circuit board with a controller and a data communication circuit, where the data communication circuit is a transmitting includes receiving device, whereby the transmitting-receiving device is configured for the transmitting an electronic data communication signal via an antenna, where the printed circuit board furthermore includes a power amplifier circuit for amplifying the electronic data communication signal for transmission thereof, whereby the power amplifier circuit has a signal input path for that purpose. has for receiving the electronic data communication signal and a power input path, where the printed circuit board furthermore includes a capacitor, where the The capacitor is designed to store electrical energy from the power supply and to release the stored electrical energy during a predetermined period provide, such that a supply signal is applied to the power input path supplied for powering the power amplifier circuit, such that it power amplifier circuit the electronic data communication signal can amplify and via a signal output path the amplified electronic can deliver a data communication signal to the antenna.
2. Label according to claim 1, where the transmitting-receiving device is configured to transmit the electronic data communication signal during a broadcasting period, during which the capacitor is designed to store the electrical to release energy during the broadcasting period.
8. Label according to claim 1 or 2, where the transmitting device is equipped for receiving or transmitting the electronic data communication signal at a frequency between 0.4 GHz and 4 GHz, preferably between 2 GHz and 3 GHz, more preferably between 2.4 GHz and 2.5 GHz.
4. Label in accordance with one of claims 1-3, where the electronic data communication signal is an asymmetrical signal, where the antenna a a dipole antenna is one that is connected to the transceiver via a balun, where the balun is configured to convert between an asymmetrical signal from the transceiver and a symmetrical signal from the dipole antenna.
5. Label according to one of the preceding claims, where the antenna along an outer edge of the printed circuit board has been applied.
6. Label in accordance with one of the preceding claims, where the label furthermore a Includes fastening element for attaching the label to the animal.
7. Label in accordance with claim 6, where the fastening element belongs to a group comprising: a reception opening designed to accommodate a pen of a to include complementary part for piercing the label, a clamp, a magnetic element and an adhesive part.
8. Label in accordance with claim 6 or 7, where the label is an ear tag and where the mounting element is located at a first distance from the printed circuit board located such that, in use, the printed circuit board and the antenna are underneath the fastening element located 9. Label in accordance with claim 8, where the label furthermore comprises a housing which includes the printed circuit board, where the housing has a rear side that is in use is directed towards an ear of the animal to which the label is attached, whereby the power supply is mounted in the housing between the printed circuit board and the rear, such that, during use, it is positioned between the printed circuit board and the ear.
10. Label according to one of the conclusions 4-9, where the dipole antenna two includes antenna arms, where the printed circuit board in use is vertical in the label placed such that the antenna arms are in a vertical plane.
11. Label according to one of the conclusions 4-10, where the dipole antenna two comprises antenna arms, where the antenna arms each follow a curved path along the outer edge of the printed circuit board.
12. Label according to claim 11, where the curved path belongs to a group that includes: circular paths, elliptical paths, parabolic paths and hyperbolic paths.
13. Label in accordance with one of the preceding claims, whereby the food at includes at least one of a battery and a solar panel.
14. Label in accordance with one of claims 1-7 or 10-13, where the label ten at least one is from a group that includes: an ear tag, a stomach bolus, a leg tag, a neck tag or a tail tag.
15. Label in accordance with one of the preceding claims, whereby the sender- receiving device is furthermore designed to receive an electronic data communication signal to be received via the antenna.