EP3147996A1

EP3147996A1 - Multi-frequency antenna module

Info

Publication number: EP3147996A1
Application number: EP16189903.4A
Authority: EP
Inventors: Loic Le Garrec
Original assignee: Johnson Electric SA
Current assignee: Johnson Electric SA
Priority date: 2015-09-25
Filing date: 2016-09-21
Publication date: 2017-03-29
Also published as: GB201517005D0; CN106558751A

Abstract

A multi-frequency antenna module (10) for use with a smart card reader (50), the multi-frequency antenna module (10) comprising a module substrate (12); a radio-frequency identification near-field communication antenna (14) affixed to the module substrate (12), the radio-frequency identification near-field communication antenna (14) defining an inner area (22) on the module substrate (12); and a far-field antenna (16) affixed within the inner area (22) of the module substrate (12). The invention further relates to a smart card reader (50) and to a method of reducing the size of a smart card reader antenna module for a smart card reader (50) having multi-frequency communication means.

Description

The present invention relates to a multi-frequency antenna module for a smart card reader, and to a smart card reader having such a multi-frequency antenna module. The invention further relates to a method of reducing the size of a smart card reader antenna module for a smart card reader having multi-frequency communication means.
In order to make payments for goods and services, it is possible for a user to utilise a smart card associated with the user's bank or credit account, having internal circuitry, which is capable of interacting with a smart card reader in order to process a payment. This removes the need for a user to carry large amounts of physical money.
Point-of-sale (POS) terminals are available to the purveyors of goods and services, and are smart card readers which are capable of interacting with a user's smart card. Traditionally, such smart card readers have required physical coupling of a smart card to a smart card reader circuit in order to process the necessary information. However, with the advent of contactless payment methods, via radio-frequency identification (RFID) of the smart card, the requirements of a smart card reader have increased.
Modem smart card readers are therefore required to provide both contact and contactless interactions with a smart card. A physical smart card contact element may be required, but also a contactless smart card reader antenna. Furthermore, the smart card reader must also be required to include a connection means to enable communication with an external source, generally, the base terminal of the smart card issuer, such as a bank.
It is possible to provide a wired connection from a smart card reader to a base terminal which has the necessary transmitter built in, but this comes at the expense of portability of the smart card reader. Most modem smart card readers are required to be wireless, and therefore must also include a far-field antenna to allow for communication with a said base unit.
Unfortunately, the inclusion of so many different components, such as the smart card contact element, the contactless antenna, and the far-field antenna, significantly increases the manufacturing cost of the smart card reader, as well as the overall volume thereof. Furthermore, the close proximity of several different frequency-tuned antennae in a single unit can result in interference effects.
It is an object of the present invention to provide a smart card reader which is enabled for multi-frequency communications whilst reducing the overall size and cost thereof, in order to limit or overcome the above-mentioned problems.
According to a first aspect of the invention, there is provided a multi-frequency antenna module for use with a smart card reader, the multi-frequency antenna module comprising: a module substrate; a radio-frequency identification near-field communication antenna affixed to the module substrate, the radio-frequency identification near-field communication antenna defining an inner area on the module substrate; and a far-field antenna mounted within the inner area of the module substrate.
By providing the two antennae required to communicate with both near-field and far-field sources on a single module substrate, the overall cost of producing a smart card reader can be substantially reduced, as well as resulting in a reduction in the internal volume of the smart card reader. Furthermore, the present arrangement serves to substantially limit the amount of interference between the two antennae so as to avoid unnecessary frequency modifications to either signal.
Preferably, the radio-frequency identification near-field communication antenna may be formed as a loop antenna having at least one turn, within which is defined the inner area of the module substrate, and the loop antenna may preferably have a plurality of turns.
A loop antenna shape for a radio-frequency identification near-field communication antenna increases the strength of the antenna significantly, enabling the near-field communication antenna to avoid being overpowered by the far-field antenna signal.
The far-field antenna may be formed as a dipole antenna, in which case a size of the far-field antenna may be related to one half of the wavelength at a frequency of interest. Alternatively, the far-field antenna may be formed as a monopole antenna, wherein a size of the far-field antenna may be related to one quarter of the wavelength at a frequency of interest.
Optimization of the far-field antenna significantly improves the effectiveness thereof, helping to overcome any interference which may occur as a result of interactions with the near-field communication antenna.
A centre of the far-field antenna may be offset relative to a centre of the radio-frequency identification near-field communication antenna in a plane of the module substrate. The H-plane of the far-field antenna may optionally be offset relative to the said centre of the radio-frequency identification near-field communication antenna. Furthermore, the said centre of the far-field antenna may be aligned with the said centre of the radio-frequency identification near-field communication antenna in a plane of the E-field of the far-field antenna.
This particular arrangement of the two antennae with respect to one another further limits the effect of interference occurring between the two, leading to more power and effective communications in each of the two frequency ranges. However, it may be feasible to have a single substrate with the antennas mounted side by side, or with the radio-frequency identification near-field communication antenna mounted within the far-field antenna.
Preferably, an area of the radio-frequency identification near-field communication antenna may match or substantially matches an area of the module substrate.
Matching the shape of the radio-frequency identification near-field communication antenna to that of the module substrate advantageously both maximises the area of the near-field communication antenna whilst also providing as much distance as possible between the near-field communication antenna and the far-field antenna to limit interference therebetween.
In a preferred embodiment, the far-field antenna may occupy less than 50% of the total area of the inner area of the module substrate.
A relatively small far-field antenna again further separates the electrically-conductive portions of the radio-frequency identification near-field communication antenna and far-field antenna to limit the amount of interference therebetween.
The far-field antenna and radio-frequency identification near-field communication antenna may be affixed to the same side of the module substrate as one another.
Putting the two antennae on the same side of the module substrate allows for the opposite side of the module substrate to be positioned between the antennae and any components of the smart card reader which may emit electromagnetic interference once installed, such as the user interface or display screen. This advantageously has the effect of shielding the antennae from further interference effects.
A terminal of the far-field antenna may be positioned adjacent to a terminal of the radio-frequency identification near-field communication antenna on the module substrate.
Collating the terminals of the antennae on the module substrate allows for the multi-frequency antenna module to be engaged with a smart card reader circuit more readily during installation, simplifying the assembly of the smart card reader.
Preferably, the module substrate may be formed from a flexible material.
A flexible substrate not only allows for a greater number of manufacturing options for the multi-frequency antenna module, but also allows for the module to be installed into the smart card reader in more configurations, which beneficially may subsequently assist with the miniaturisation of the smart card reader in the future.
According to a second aspect of the invention, there is provided a multi-frequency antenna module for use with a smart card reader, the multi-frequency antenna module comprising: a module substrate; and a near-field communication antenna and a far-field antenna mounted on the module substrate.
According to a third aspect of the invention, there is provided there is provided a multi-frequency antenna module for use with a smart card reader, the multi-frequency antenna module comprising: a module substrate; a near-field communication antenna affixed to the module substrate, the near-field communication antenna defining an inner area on the module substrate; and a far-field antenna mounted within the inner area of the module substrate.
Preferably, the near-field communication antenna may be a radio-frequency identification antenna, in which case, the far-field antenna may be a non-radio-frequency identification antenna.
An RFID antenna beneficially allows a POS reader to engage in contactless communication with a smart card via its multi-frequency antenna module, with the far-field antenna being provided to communicate with an external source via non-RFID means. This advantageously minimises the interference between the two antennae.
According to a fourth aspect of the invention, there is provided a smart card reader comprising: a smart card reader body having a user interface and/or display thereon; a smart card reader circuit arranged to read a smart card in communication with the smart card reader; and a multi-frequency antenna module, preferably in accordance with the first aspect of the invention, the multi-frequency antenna module being in communication with the smart card reader circuit to enable communication with an external source via at least one of near-field communication means and far-field communication means.
A smart card reader having a multi-frequency antenna module as hereto described is advantageously capable of interacting with a contactless smart card and a third party verification device, and both functionalities can then be provided by installation of a single module. This advantageously allows for a more cost-effective construction of smart card reader, and potentially allows for a smaller smart card reader to be manufactured.
At least one of the far-field antenna and near-field communication antenna may preferably be positioned on a side of the module substrate which is distal to the user interface and/or display of the smart card reader.
Positioning the antennae of the module away from other electrically active components of the smart card reader beneficially shields the antennae from any deleterious electromagnetic interference from said components, thereby improving the overall performance of the antennae.
According to a fifth aspect of the invention, there is provided a method of reducing the size of a smart card reader antenna module for a smart card reader having multi-frequency communication means, the method comprising the steps of: providing a module substrate having a near-field communication antenna affixed thereon which defines an inner area of the module substrate; and affixing a far-field antenna within the said inner area.
The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a top plan representation of a first embodiment of a multi-frequency antenna module in accordance with the first aspect of the invention;
Figure 2 shows a top plan representation of one embodiment of a smart card reader in accordance with the fourth aspect of the invention, the position of a multi-frequency antenna module as shown in Figure 1 being shown thereon; and
Figure 3 shows a top plan representation of a second embodiment of a multi-frequency antenna module in accordance with the first aspect of the invention.

Referring firstly to Figure 1, there is illustrated a multi-frequency antenna module, indicated globally at 10, which is particularly designed for installation into a smart card reader or point-of-sale (POS) terminal 50, such as that shown in Figure 2.
The multi-frequency antenna module 10 is formed so as to have a planar or substantially planar module substrate 12, which is here formed as a rectangular sheet. However, any suitable circular or non-circular substrate may be utilised, and/or the substrate may not necessarily be planar, for example, the substrate may be curved in one or more dimensions.
The module substrate 12 may typically be formed as a printed circuit board, for example, formed from FR4 material, but flexible printed circuits are becoming increasingly used in the electronics sector, and a flexible module substrate 12 may be utilised, formed from a flexible material such as polyethylene terephthalate (PET) or a polyimide (PI).
Affixed to the module substrate 12 are two antennae: a near-field communication (NFC) antenna 14; and a far-field antenna 16. In the depicted embodiment, the near-field communication antenna 14 is formed as a loop 18 of electrically conductive material which follows a path around or substantially around a perimeter 20 of the module substrate 12.
The loop 18 of the near-field communication antenna 14 thus defines an inner area 22 on the module substrate 12 which is not occupied by the electrically conductive material of the loop 18 which, in ordinary circumstances, would remain unutilised. The loop 18 substantially bounds this inner area 22 of the module substrate 12, and has two terminals 24 which each extend to an edge 26 of the module substrate 12 to allow for the near-field communication antenna 14 to be connected to other modules and/or circuitry.
Whilst the loop 18 of the near-field communication antenna 14 is here illustrated as being a square loop to define the inner area 22 on the module substrate 12, it will be appreciated that many different types of shapes and form of near-field communication antennae are known, and could define a bounded inner area 22. At the very least, other forms of loop are known, such as circular loop antennae, or irregularly-shaped loops, following a circuitous, tortuous or serpentine path across the module substrate 12 could be envisaged. Similarly, rod antennae having elongate paths around the module substrate 12 could be utilised.
The far-field antenna 16 is formed here as a Wi-Fi antenna, having a substantially rectangular antenna body 28 from which extends a single terminal 30. The far-field antenna body 28 is positioned on the module substrate 12 within the inner area 22 bounded by the near-field communication antenna 14. The far-field antenna terminal 30 is beneficially formed near to the near-field communication antenna terminals 24, thereby enabling simple engagement of the terminals 24, 30 with an external circuit simultaneously.
A Wi-Fi antenna will tend to operate at a frequency of around 2.4GHz, but other short-wavelength radio-frequency wireless standards are available, and the far-field antenna 16 can be optimized for such frequencies. Other modes of wireless communication are also available, such as: general packet radio services (GPRS) often referred to as 2.5G telephony when combined with 2G cellular technology, which operates in the 900 and 1800 MHz bands; universal mobile telecommunications system (UTMS), known as 3G telephony, operating in the 2100MHz band; or long-term evolution (LTE) communications, referred to as 4G, operating in the 2600MHz band. The far-field antenna 16 could be optimised for any of these wireless standards, or, indeed, for satellite communications (GPS), which typically operates in the 1.575GHz frequency band.
Regardless of which type of far-field antenna 16 is chosen, it is affixed to the module substrate 12 within the inner area 22 thereof. This may be performed by, for instance, etching of a metallic or similarly electrically conductive material onto the surface of the module substrate 12, or a conductive track may be deposited onto the module surface 12 to form either the near-field communication antenna 14 or the far-field antenna 16. Other means of applying antennae to a substrate will be well-known to the skilled person.
Typically, the near-field communications antenna 14 and far-field antenna 16 are positioned on a first side 32 of the module substrate 12; however, it will be apparent that the far-field antenna 16 could be positioned on an opposite side of the module substrate 12 to the near-field communication antenna 14. In such a case, clearly there is no physically-defined inner area 22 on the said opposite side of the module substrate 12, but the inner area 22 defined on the first side 32 of the module substrate 12 can be effectively superimposed onto the opposite side to define a corresponding inner area thereon.
It will also be apparent that antennae 14, 16 could be provided which span more than one side of the module substrate 12; this may be of particular interest for the near-field communication antenna 14, where a large number of turns to the loop 18 may be desirable.
If the antennas are located on opposite sides of a single substrate, then it may be feasible to provide a layer of anti-interference or shielding material therebetween to further reduce interference between the two antennas.
The near-field communication antenna 14 is preferably designed to act as a radio-frequency identification (RFID) antenna, and therefore will operate most effectively if a large number of turns are utilised in the loop 18. On the other hand, the far-field antenna 16 is designed to interact with distant radio signals, and therefore needs to be sized appropriately in order to best communicate at the frequency of interest. For a monopole antenna, this means sizing the far-field antenna 16 in relation to one quarter of the radio wavelength, whereas for a dipole antenna, the far-field antenna 16 should be sized in relation to one half of the radio wavelength.
In use, and as illustrated in Figure 2, the multi-frequency antenna module 10 can be installed into a smart card reader 50, housed within a smart card reader body 52 thereof. Typically, smart card readers 50 acting as POS terminals will have a user interface 54, generally including at least a plurality of input keys, and generally a smart card receiving slot into which a smart card can be inserted for contact interaction with a smart card reader circuit internal to the smart card body 52. There will also generally be a display screen 56 associated with the smart card reader 50 to display information regarding a transaction to a user, and the smart card reader circuit will generally be positioned within the smart card reader body 52 at or adjacent to the user interface 54 and/or display screen 56.
Generally, a POS terminal will also include a receipt printer from which transaction receipts can be printed and dispensed via a receipt exit aperture 58. In the depicted embodiment, the multi-frequency antenna module 10 is preferably mounted at or adjacent to the receipt exit aperture 58. It is preferred that the near-field communication antenna 14 and far-field antenna 16 are positioned on the side 32 of the module substrate 12 which faces away from the user interface 54 and/or display screen 56 so as to again reduce the effects of electromagnetic interference from these components. Furthermore, the module substrate 12 may be located at, on or around the distal end of the POS terminal, furthest from the user interface or keypad 54 and/or display screen 56.
The multi-frequency antenna module 10 is engaged with the smart card reader circuit to enable wireless communications to occur with the smart card reader circuit. The near-field communication antenna 14 allows for contactless interaction between a smart card and the smart card reader 50, allowing a user to make a payment via the POS terminal more rapidly than via insertion of a smart card into a smart card receiving slot.
The far-field antenna 16 then allows the smart card reader 50 to communicate with a third party external to the smart card reader 50, such as the smart card user's issuing bank. A Wi-Fi or similar short-wavelength far-field antenna 16 would typically be arranged to communicate at short range with a local base station which was in networked communication with the third party. A GPRS, UMTS or LTE far-field antenna 16 may be better placed to communicate directly with the third party, whereas a GPS communication means may act as a secure intermediary between the smart card reader 50 and the third party.
By providing the near-field communication antenna 14 and far-field antenna 16 on a single module substrate 12, the manufacturing costs of the smart card reader 50 can be reduced, as only a single multi-frequency antenna module 10 need be produced instead of two. Furthermore, the spatial requirements of the antenna module 10 are reduced when compared with a plurality of individual modules, thereby resulting in a smaller smart card reader 50. B carefully positioning the two antennae relative to each other, interference between the two is prevented or limited to within acceptable levels, and this has been the issue to date preventing co-mounting of such antennae.
A second embodiment of a multi-frequency antenna module is illustrated in Figure 3, indicated globally as 110. Similar or identical references will be hereafter used to refer to similar or identical features to those of the first embodiment, and further detailed description is omitted for brevity.
In the second embodiment, the module substrate 112 is again preferably rectangular in profile, and the near-field communication antenna 114 may conveniently substantially follow the perimeter 120 thereof as a loop 118 to define an inner area 122 on the module substrate 112. However, the loop 118 is here formed having a plurality of turns so as to circuit the module substrate 112 several times over. The far-field antenna 116 is again also preferably formed so as to have a rectangular antenna body 128.
The repeated turns of the near-field communication antenna 114 cause issues for the terminals 124, 130 of the two antennae 114, 116, since the inner area 122 becomes completely bounded. As such, there must be provided at least a first bridge 134 for an inner terminal 124i of the near-field communication antenna 114, and a second bridge 136 for the far-field antenna terminal 130, such that each terminal 124i, 130 is able to reach an edge 126 of the module substrate 112.
In this particular embodiment, the far-field antenna 116 is a Wi-Fi antenna having an area of 40mm by 15mm, whereas the near-field communication antenna 114 is formed as a loop 118 having three turns, a complete area of 50mm by 70mm and a turn width of 1mm, each turn being separated by a gap of 0.5mm. As such, the far-field antenna 116 occupies less than half of the inner area 122.
It will be noted that there are three primary means by which the antennae 114, 116 may interact deleteriously: firstly, where the two antennae 114, 116 are in close proximity to one another, they may interact and couple, resulting in frequency modification; secondly, electromagnetic interference at or adjacent to the terminals 124, 130 of the near-field communication antenna 114 and far-field antenna 116 may result in an impedance mismatch which affects the far-field antenna 116 in particular; and finally, where the E- and H-planes of the far-field antenna 116 intersect with the near-field communication antenna 114, respectively aligned to the lateral and longitudinal axes of the far-field antenna body 128, a shielding effect is experienced, distorting the radiation pattern of the far-field antenna 116.
The arrangement of the two antennae 114, 116, such that the far-field antenna 116 is spaced apart at least in part from some of the loop 118 from the near-field communication antenna 114, ensures that the interference effects are reduced to acceptable levels, enabling satisfactory performance for both antennae 114, 116 at their desired frequencies.
This can be achieved in particular by offsetting at least one of the central longitudinal or lateral axes of the far-field antenna 16 with the corresponding axes of the near-field communication antenna 14; in the depicted embodiment, the E-plane in the lateral axis of the far-field antenna 16 is aligned to the longitudinal axis of the near-field communication antenna 14, whereas the H-plane, in the longitudinal axis of the far-field antenna 16, is misaligned with the lateral axis of the near-field antenna 14.
It will be appreciated that although the multi-frequency antenna module has hereto been described as being distinct from any smart card reader circuit, it may be possible to extend the present invention so as to provide a complete substrate which incorporates both the smart card reader circuit and the multi-frequency antenna module thereon.
Furthermore, whilst the near-field communication antenna has been described as being an RFID antenna, with the far-field antenna being arranged for non-radio-frequency identification communication, it will be appreciated that other near-field communication means could be provided for, such as short-wavelength ultra-high radio frequency communication means, with the near-field communication antenna being proportioned accordingly.
It is therefore possible to provide a multi-frequency antenna module upon which is position both a near-field communication antenna and a far-field communication antenna such that the performance of each antenna is within acceptable bounds, thereby reducing the manufacturing costs of the antenna module, and also reducing the size constraints on a smart card reader into which the antenna module is to be installed.
The words 'comprises/comprising' and the words 'having/including' when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components, but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.
It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.
The embodiments described above are provided by way of examples only, and various other modifications will be apparent to persons skilled in the field without departing from the scope of the invention herein described and defined.

Claims

A multi-frequency antenna module (10) for use with a smart card reader (50), the multi-frequency antenna module (10) comprising:
a module substrate (12); and

a near-field communication antenna (14) and a far-field antenna (16) mounted on the module substrate (12).
A multi-frequency antenna module (10) as claimed in claim 1, wherein the near-field communication antenna (14) is a radio-frequency identification antenna.
A multi-frequency antenna module (10) as claimed in claim 1 or 2, wherein the far-field antenna (16) is a non-radio-frequency identification antenna.
A multi-frequency antenna module (10) as claimed in any one of claim 1 to 3, the near-field communication antenna (14) defines an inner area (22) on the module substrate (12), and the far-field antenna (16) is mounted within the inner area of the module substrate (12).
A multi-frequency antenna module (10) as claimed in claim 4, wherein the near-field communication antenna (14) is formed as a loop (18) antenna having at least one turn, within which is defined the inner area (22) of the module substrate (12).
A multi-frequency antenna module (10) as claimed in any one of claims 1 to 5, wherein the far-field antenna (16) is formed as a dipole antenna.
A multi-frequency antenna module (10) as claimed in any one of claims 1 to 5, wherein the far-field antenna (16) is formed as a monopole antenna.
A multi-frequency antenna module (10) as claimed in any one of the preceding claims, wherein a centre of the far-field antenna (16) is offset relative to a centre of the near-field communication antenna (14) in a plane of the module substrate (12).
A multi-frequency antenna module (10) as claimed in claim 8, wherein a H-plane of the far-field antenna (16) is offset relative to the said centre of the near-field communication antenna (14).
A multi-frequency antenna module (10) as claimed in claim 8 or 9, wherein the said centre of the far-field antenna (16) is aligned with the said centre of the near-field communication antenna (14) in a plane of the E-field of the far-field antenna (16).
A multi-frequency antenna module (10) as claimed in any one of the preceding claims, wherein a terminal (30) of the far-field antenna (16) is positioned adjacent to a terminal (24) of the near-field communication antenna (14) on the module substrate (12).
A multi-frequency antenna module (10) as claimed in any one of the preceding claims, wherein the module substrate (12) is formed from a flexible material.
A smart card reader (50) comprising:
a smart card reader body (52) having a user interface (54) and/or display (56) thereon;

a smart card reader circuit arranged to read a smart card in communication with the smart card reader; and

a multi-frequency antenna module (10) as claimed in any one of the preceding claims, the multi-frequency antenna module (10) being in communication with the smart card reader circuit to enable communication with an external source via at least one of near-field communication means (14) and far-field communication means (16).
A smart card reader (50) as claimed in claim 13, wherein at least one of the far-field antenna (16) and near-field communication antenna (14) are positioned on a side of the module substrate (12) which is distal to the user interface (54) and/or display (56) of the smart card reader (50).
A method of reducing the size of a smart card reader antenna module (10) for a smart card reader (50) having multi-frequency communication means, the method comprising the steps of: providing a module substrate (12) having a near-field communication antenna (14) affixed thereon which defines an inner area (22) of the module substrate (12); and affixing a far-field antenna (16) within the said inner area (22).