Abstract:
An electronic communications device includes a body of semiconductor material with an integrated electronic circuit, an inductive element, and a capacitive element. The capacitive element is formed by a first electrode and a second electrode positioned between the inductive element and the integrated electronic circuit. Tuning of the device circuitry is accomplished by energizing the inductive/capacitive elements, determining resonance frequency, and using a laser trimming operation to alter the structure of one or more of the first electrode, second electrode or inductive element and change the resonance frequency.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a divisional application from U.S. application for patent Ser. No. 13/032,854 filed Feb. 23, 2011, now U.S. Pat. No. 9,112,263, which claims priority to Italian Patent Application No. TO2010A000140, filed Feb. 25, 2010, which applications are incorporated herein by reference in their entireties. 
     
    
     TECHNICAL FIELD 
       [0002]    An embodiment relates to an electronic communications device with antenna and electromagnetic shield. 
       BACKGROUND 
       [0003]    As is known, numerous electronic communications devices are today available, which are able to communicate with other electronic devices by means of techniques of coupling of an inductive or electromagnetic type. In particular, these electronic communications devices are provided with a transmitter circuit and at least one antenna coupled to the transmitter circuit. The transmitter circuit is able to drive the antenna in such a way that it generates an electromagnetic field having at least one electrical characteristic (for example, the amplitude, frequency, or phase) modulated with information to be transmitted. Consequently, other electronic devices that receive this electromagnetic field may demodulate the information transmitted. 
         [0004]    Considering a generic electronic transmitter device, which generates a given electromagnetic field at least one operating frequency, and a generic electronic receiver device, which is set at a distance h from the transmitter device and receives the given electromagnetic field, between the electronic transmitter device and the electronic receiver device a communications channel is set up, which may also be obtained via a coupling of a magnetic type. In practice, in the case of magnetic or inductive coupling, the information is transmitted principally thanks to a magnetic field generated by the antenna of the electronic transmitter device, whereas, in the case of electromagnetic transmission, the information is transmitted through the propagation of electromagnetic waves generated by the antenna. Consequently, in the case of magnetic or inductive coupling, it is common to use a single or multiple loop antenna, and in this case the electrical behavior of the antenna is equivalent to that of an inductor. In greater detail, in the case of inductive coupling, the antenna can be equated, to a first approximation, to a reactive element, whereas in the case of electromagnetic transmission, the antenna can be equated, to a first approximation, to a resistive element. 
         [0005]    In the present document, reference is made to antennas in general, implying the possibility that, in given conditions (and hence, in given applications), these are equivalent, from a circuit standpoint and to a first approximation, to corresponding inductors. 
         [0006]    Once again with reference to electronic communications devices, the antennas considered herein may be of a different type, such as for example patch antennas or gain loop antennas, the latter being also known as “magnetic-dipole antennas” and finding particular use in the field of radio-frequency-identification (RFID) applications. For example, in the case of loop antennas, it may be possible for them to be arranged, within the respective electronic communications devices, in such a way that, in top plan view, they surround, or else are set on top of, the corresponding transmitter circuits. In general, it may in any case be possible that, given an electronic communications device, the respective antenna interferes, in use, with the respective transmitter circuit. In order to reduce the interference, there are known electronic communications devices of the type illustrated in  FIG. 1 . 
         [0007]    In detail, the electronic communications device shown in  FIG. 1 , which for convenience in what follows will be referred to as “device  1 ”, comprises: a body of semiconductor material  2 , which defines a first top surface  2   a  and in turn comprises a substrate of semiconductor material possibly set on top of which are one or more epitaxial layers (not shown); a top region  4 , which extends on the first top surface  2   a  of the body of semiconductor material  2 , and defines a second top surface  4   a;  a metal shield  6 , which extends on the second top surface  4   a;  a silicon-oxide layer  8 , which extends on the metal shield  6 ; a plurality of metal turns  10 , for example of a circular or polygonal shape, which are coplanar and concentric, extend above, and in contact with, the silicon-oxide layer  8  and form, as a whole, an antenna  12 ; and a possible protective layer  14 , which extends on the silicon-oxide layer  18 , and extending within which are the aforementioned metal turns  10 . 
         [0008]    Yet in greater detail, formed within the body of semiconductor material  2  is an electronic circuit. In addition, the top region  4  may comprise dielectric layers and conductive paths formed by metallizations and vias, which are generally coupled to the body of semiconductor material  2  so as to enable connection of the electronic circuit with the antenna  12 , as described below. In particular, in  FIG. 1  the metallizations are shown in a qualitative way and are designated by  16 . In addition, a first metallization and a second metallization, which are designated, respectively, by  16   a  and  16   b,  are coupled to the metal shield  6 , respectively, by means of a first vertical metal connection  18   a  and a second vertical metal connection  18   b.  In particular, as illustrated qualitatively in  FIG. 1 , the metal shield  6  may be of a planar type, but may have different shapes, such as, for example, shapes known as “cross-bar pattern”, “halo-ground contact”, “narrow-bar pattern”, “wide-bar pattern”, “solid-ground pattern”, “perforated-ground pattern”, and illustrated in  FIGS. 2   a - 2   f , respectively. 
         [0009]    Finally, as regards in particular the antenna  12 , the metal turns  10  that form it may have different widths, but are in any case in ohmic contact with one another, as shown by way of example in  FIG. 3 , in such a way that it is possible to define a start terminal  20   a  and an end terminal  20   b  of the antenna  12 . These start and end terminals  20   a,    20   b  are coupled, respectively, by means of a first metal via  22   a  and a second metal via  22   b,  to the metal shield  6 . In particular, the first and second metal vias  22   a,    22   b  contact the metal shield  6  at points corresponding, respectively, to the points in which the first and second vertical metal connections  18   a,    18   b  contact in turn the metal shield  6 . 
         [0010]    From a circuit standpoint, the metal shield  6  may be floating or else coupled to ground. In either case, its function is that of limiting any mutual interference between the antenna  12  and the electronic circuit formed in the body of semiconductor material  2 . In addition, the shape assumed by the metal shield  6  may be optimized for limiting, in use, onset of loop currents within the metal shield  6  itself, which in turn could interfere with the behavior of the antenna  12 . Further known variants envisage use, in lieu of the metal shield  6 , of a polysilicon shield in order to prevent undesirable reflections of the electromagnetic field generated by the antenna  12 . 
         [0011]    As regards, instead, the first and second metal vias  22   a,    22   b,  as well as the silicon-oxide layer  8  and the possible protective layer  14 , they may be designed so as to match the impedance of the antenna  12  with the impedance of the electronic circuit. 
         [0012]    In general, the antennas present in electronic communications devices of a known type may be, amongst other things, antennas of a so-called LC type, i.e., formed (from an equivalent-circuit standpoint) by an inductor coupled, either in series or in parallel, to a corresponding capacitor. In this way, the behavior of each antenna may be optimized, in particular as regards the conditions of inductive coupling (also known as resonance conditions), for a respective resonance frequency f, which depends upon the inductance associated with the inductor and the capacitance of the capacitor to which the inductor is coupled, according to the relation LCω2=1, where ω=2πf. 
         [0013]    In the present electronic communications devices, there hence arises the problem of obtaining these capacitors with sufficient precision and of connecting them to the respective antennas. In particular, electronic communications devices of the type shown in WO2007/086809, which is incorporated by reference, are known, in which the capacitors, and in particular the electrodes of the capacitors themselves, are arranged underneath the respective metal shields. In particular, these capacitors are integrated in the electronic communications devices, either within the respective bodies of semiconductor material or else within the respective top regions. In either case, this entails an increase of the overall dimensions of the electronic communications devices, and in particular of the area of the electronic communications devices. 
       SUMMARY 
       [0014]    An embodiment is an electronic communications device with antenna and electromagnetic shield, which will enable the drawbacks of the known art to be at least partially overcome. 
         [0015]    In an embodiment, a system for tuning a resonant circuit comprised of an inductive circuit portion and a capacitive circuit portion comprises: a transparent substrate; a test antenna supported by the transparent substrate; an automated test equipment circuit coupled to the test antenna and configured to apply a variable signal to said test antenna for communication to said resonant circuit to identify a resonant frequency of said resonant circuit; and a trimming laser configured to emitting a laser beam through said transparent substrate to effectuate a trimming of a structure of at least one of the inductive circuit portion and the capacitive circuit portion for adjusting the resonant frequency. 
         [0016]    In an embodiment, a method comprises: energizing a resonant circuit comprised of an inductive circuit portion and a capacitive circuit portion; identifying a resonant frequency of said resonant circuit from said energizing; and emitting a laser beam to effectuate a trimming of a structure of at least one of the inductive circuit portion and the capacitive circuit portion for adjusting the resonant frequency. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    One or more embodiments are now described, purely by way of non-limiting example and with reference to the attached drawings, wherein: 
           [0018]      FIG. 1  shows a cross section of an electronic communications device of a known type; 
           [0019]      FIGS. 2   a - 2   f  show top plan views of examples of electromagnetic shields of a known type; 
           [0020]      FIG. 3  shows a perspective view of the electronic communications device shown in  FIG. 1 ; 
           [0021]      FIGS. 4 and 8  show cross sections of embodiments of an electronic device; 
           [0022]      FIG. 5  shows a cross section of the embodiment shown in  FIG. 4 ; 
           [0023]      FIG. 6  shows a top plan view with portions removed of an embodiment of an electronic device; 
           [0024]      FIGS. 7   a  and  7   b  show equivalent circuit diagrams of embodiments of an electronic device; 
           [0025]      FIGS. 9 and 10  show cross sections of the embodiment shown in  FIG. 8 ; 
           [0026]      FIGS. 11 and 12  show cross sections of a different embodiment of an electronic device; 
           [0027]      FIGS. 13   a  and  13   b  show cross sections of a further embodiment of an electronic device; 
           [0028]      FIG. 13   c  shows an equivalent electrical circuit of the embodiment the cross sections of which are shown in  FIGS. 13   a  and  13   b;    
           [0029]      FIGS. 13   d  and  13   e  show cross sections of a further embodiment of an electronic device; 
           [0030]      FIG. 13   f  shows an equivalent electrical circuit of an embodiment of an electronic device; 
           [0031]      FIG. 14  is a perspective view of an embodiment of an electronic device and of an automatic measurement and calibration system; 
           [0032]      FIG. 15  is a perspective view with portions removed of a further embodiment of an electronic device; and 
           [0033]      FIG. 16  is a schematic illustration of a communications system comprising an embodiment of an electronic device. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]      FIG. 4  shows an embodiment of an electronic communications device, which is designated by  30  and which will be referred to in what follows, for reasons of simplicity, as “communications device  30 ”. In detail, the communications device  30  comprises: a body of semiconductor material  32 , which defines a first top surface  32   a  and comprises in turn a substrate of semiconductor material (not shown) possibly set on top of which are one or more epitaxial layers (not shown); a top region  34 , which extends on the first top surface  32   a  and defines a second top surface  34   a;  an electromagnetic shield  36 , which extends on the second top surface  34   a;  a dielectric layer  38  (for example, made of silicon oxide), which extends on the electromagnetic shield  36  and defines a third top surface  38   a;  a plurality of metal turns  40 , which may be, for example, of a circular or polygonal shape, and which are coplanar and concentric, extend above and in contact with the dielectric layer  38 , and form, as a whole, an antenna  42 ; and a possible protective layer  44 , which extends on the dielectric layer  38 , and extending within which are the aforementioned metal turns  40 . Alternatively, the metal turns  40  of the antenna  42  may be formed within the dielectric layer  38 , for example in contact with the top surface  38   a  (case not shown) in such a way that the protective layer  44  protects the antenna  42 . 
         [0035]    In still greater detail, formed within the body of semiconductor material  32  is at least one electronic circuit. In addition, the top region  34  may comprise dielectric layers and conductive paths formed by metallizations and vias, these conductive paths being generally coupled to the body of semiconductor material  32  so as to enable connection of the electronic circuit with the antenna  42 , as described hereinafter. 
         [0036]    In particular, set between the electronic circuit and the antenna  42  is hence the electromagnetic shield  36 , which, in the embodiment illustrated, comprises a first electrode  50  and a second electrode  52 , coplanar and comb-fingered to one another, hence not in ohmic contact, as shown in  FIG. 5 . In practice, the first and second electrodes  50 ,  52 , and hence the electromagnetic shield  36  itself, form a capacitor C. 
         [0037]    Both the first electrode  50  and the second electrode  52  are coupled to the electronic circuit present in the body of semiconductor material  32 , respectively, through at least one first metal connection  51  and a second metal connection  53 , which extend in the top region  34  and may comprise dielectric layers and metallizations. In particular, both the first metal connection  51  and the second metal connection  53  may comprise pads  51   a,    53   a,  in direct contact with the first electrode  50  and the second electrode  52 , respectively. 
         [0038]    Furthermore, both the first electrode  50  and the second electrode  52  are coupled to the antenna  42  by means of a first metal via  54  and a second metal via  56 , respectively, which extend through the dielectric layer  38 . In particular, the first metal via  54  is in ohmic contact with the first electrode  50  and with a first point of contact  60  of the antenna  42 , while the second metal via  56  is in ohmic contact with the second electrode  52  and a second point of contact  62  of the antenna  42 , for example, at a maximum distance from the first point of contact  60 , where this distance is measured along the metal turns  40  of the antenna  42  itself. In other words, in the example shown, the first and second points of contact  60 ,  62  coincide with the terminals of the antenna  42 . In addition, the capacitor C is set in parallel with respect to the antenna  42 . 
         [0039]    As shown in  FIG. 6 , the first and second electrodes  50 ,  52  may have shapes different from the ones previously shown. In particular, if we define a reference system x, y, z fixed with respect to the communications device  30 , and with the electromagnetic shield  36  lying parallel to the plane xy, the first and second electrodes  50 ,  52  may have comb-fingered shapes comprising, respectively, first and second elongated portions  41   a  and  41   b,  parallel to one another and inclined, for example by forty-five degrees, with respect to the plane xz or yz. Further and yet other geometrical shapes are in any case possible for the first and second electrodes  50 ,  52 . 
         [0040]    The capacitor C, and hence the first and second electrodes  50 ,  52 , are coupled to the electronic circuit formed within the body of semiconductor material  32 . As shown by way of example in  FIG. 7   a , this electronic circuit may comprise a number of sub-circuits, such as, for example, a transceiver circuit  70  and a converter circuit  72  of an AC/DC type. In this case, once again by way of example, the transceiver circuit  70  may be coupled to the first and second electrodes  50 ,  52 , respectively, through the first and second metal connections  51 ,  53 , as well as through the first and second pads  51   a,    53   a.  Likewise, the converter circuit  72  may be coupled to the first and second electrodes  50 ,  52 , respectively, through a third metal connection  74  and a fourth metal connection  76 , which may comprise, respectively, a third pad  74   a  and a fourth pad  76   a,  in direct contact with the first and second electrodes  50 ,  52 , respectively. 
         [0041]    Alternatively, as shown by way of example in  FIG. 7   b , the fourth metal connection  76  may share the second pad  53   a  with the second metal connection  53 . In either case, it may be possible, for example prior to forming the antenna  42  and the capacitor C, to contact the first, second, third, and possibly fourth pads  51   a,    53   a,    74   a,    76   a,  for example with the terminals of probes coupled to an automatic measurement system. By means of this automatic measurement system, it may hence be possible to test the electronic circuit easily; in particular, it may be possible to carry out independently the test on possible sub-circuits of the electronic circuit, such as, for example, the transceiver circuit  70  and the converter circuit  72 . 
         [0042]    According to another embodiment, illustrated in  FIGS. 8-10 , one between the first and second electrodes  50 ,  52  of the capacitor C extends beyond the electromagnetic shield  36 . In particular, in  FIG. 8 , the first electrode  50  is formed by a first portion  50   a  and a second portion  50   b.  As shown in  FIG. 9 , the first portion  50   a  is coplanar to the second electrode  52 , from which it is ohmically uncoupled, and forms with the second electrode  52  the electromagnetic shield  36 . Instead, as shown in  FIG. 10 , the second portion  50   b  may be set coplanar with respect to the antenna  42 , and may be set, for example, within an internal portion  43  defined by the metal turns  40 . For example, the second portion  50   b  may extend above the third top surface  38   a,  possibly within the protective layer  44 . 
         [0043]    In greater detail, the first and second portions  50   a,    50   b  are set in ohmic contact with one another in order to form the first electrode  50 . The ohmic contact may be provided by coupling the first and second portions  50   a,    50   b  by means of a third metal via  80 , which extends through the dielectric layer  38 . 
         [0044]    Purely by way of example, in the embodiment shown in  FIGS. 8-10 , the second electrode  52  has an elongated element  82 , departing from which, in a direction orthogonal to the elongated element  82  itself, are a first plurality and a second plurality of horizontal elements, which are designated, respectively, by  84   a  and  84   b  and are in ohmic contact with the elongated element  82 . The first and second horizontal elements  84   a,    84   b  extend, respectively, on opposite sides with respect to the elongated element  82  and in such a way that each first horizontal element  84   a  is in ohmic contact with, and is specular to, a corresponding second horizontal element  84   b,  with respect to the elongated element  82 . Between pairs of first contiguous horizontal elements  84   a  and pairs of second contiguous horizontal elements  84   b,  respective gaps are present. 
         [0045]    The first portion  50   a  of the first electrode  50  surrounds the second electrode  52  and has a complementary shape so as to be comb-fingered with the second electrode  52 . In particular, the first portion comprises a metal path  86 , for example of a rectangular shape (to a first approximation), which surrounds the second electrode  52  and departing from which are third horizontal elements  88 , ohmically coupled to the metal path  86  and arranged within the gaps defined by the second electrode  52 . The rectangular metal path  86  is open in order to prevent onset of parasitic currents in the turn that would be created if the rectangular metal path  86  were closed. 
         [0046]    As regards, instead, the second portion  50   b  of the first electrode  50 , it may have, for example, a shape similar to that of the second electrode  52 , except as regards the proportions. In particular, if we designate by  92 ,  94   a  and  94   b,  respectively, the elongated element and the first and second pluralities of horizontal elements of the second portion  50   b,  one between the horizontal elements  94   a  may present, at its own end not coupled to the elongated element  92 , a radiusing portion  96 , which departs from the end parallel to the elongated element  92  and contacts the third metal via  80 . 
         [0047]    In practice, in this embodiment, the second portion  50   b  contacts the first portion  50   a  through the third metal via  80 , and the first portion  50   a  contacts in turn the antenna  42  through the first metal via  54 . 
         [0048]    Likewise possible are embodiments (not shown) in which both the first electrode  50  and the second electrode  52  of the capacitor C extend beyond the electromagnetic shield  36  and comprise respective portions coplanar to the antenna  42 . These coplanar portions may be arranged within the internal portion  43  defined by the metal turns  40  and may moreover form a further comb-fingered capacitor. 
         [0049]    Likewise possible are embodiments of the type illustrated in  FIGS. 11 and 12 , in which the aforementioned third metal via  80  is not present. In particular, the second portion  50   b  is in direct contact with the antenna  42 , i.e., without interposition of any metal via. In detail, the second portion  50   b  is in direct contact with the innermost metal turn of the antenna  42 . In practice, in this embodiment, the second portion  50   b  is formed by a plurality of conductive elements  100 , each of which is ohmically coupled to a corresponding point of the aforementioned innermost metal turn. Given that it is in ohmic contact with the antenna  42 , and since the first metal via  54  is coupled, not only to the antenna  42 , but also to the first portion  50   a,  the first and second portions  50   a,    50   b  define once again the first electrode  50 . Again, the first portion  50   a  has a shape such as to prevent formation of closed loops, inside which parasitic currents may flow. 
         [0050]    As shown in  FIGS. 13   a - 13   b,  it is likewise possible for the electromagnetic shield  36  to comprise further electrodes, such as, for example, a third electrode  58 . As shown in  FIG. 13   a , the first, second, and third electrodes  50 ,  52 ,  58  may be coplanar and form a comb-fingered structure, in which the third electrode  58  is ohmically uncoupled from the first and second electrodes  50 ,  52 , and the first electrode  50  is surrounded at least in part by the second and third electrodes  52 ,  58 . 
         [0051]    In this case, the first, second, and third electrodes  50 ,  52 ,  58  may be coupled, respectively, to a reference potential GND, to a first potential V1, and to a second potential V2. In addition, the third electrode  58  may be coupled to the antenna  42 . In particular, the third electrode  58  may be ohmically coupled to the antenna  42  through a third-electrode via  55 . In this embodiment, the first metal via  54  contacts (in addition to the first electrode  50 ) the antenna  42  in a point comprised, for example, between the points of the antenna  42  of contact, respectively, with the second metal via  56  and with the third-electrode via  55 . 
         [0052]    As shown by way of example in  FIG. 13   b  (where in this embodiment the first electrode  50  is without the second portion  50   b ), these points of the antenna  42  of contact, respectively, with the second metal via  56  and with the third-electrode via  55  may coincide with the terminals of the antenna  42  itself, and the point in which the first metal via  54  contacts the antenna  42  may be equidistant with respect to the terminals of the antenna  42 , measuring the distances along the metal turns  40 . In these conditions, the equivalent electrical circuit of the antenna  42  and of the electromagnetic shield  36  is the one shown in  FIG. 13   c . It is, however, also possible that, in this embodiment, the first metal via  54  is absent. 
         [0053]    In practice, the antenna  42  of the embodiments shown in  FIGS. 13   a ,  13   b  is a differential antenna. Consequently, to optimize operation of the communications device  30 , it may be possible to create the antenna  42  in such a way that it has a shape having a high degree of symmetry, as shown for example in  FIG. 13   e , moreover providing the first, second, and third electrodes  50 ,  52 ,  58  in such a way that the electromagnetic shield  36  will also have a high degree of symmetry. In particular, as shown in  FIG. 13   e , the antenna  42  may be formed on two metallization levels, which may be coupled by metal vias, and hence a portion (not shown) of the antenna  42  may possibly be coplanar with the electromagnetic shield  36 , in particular as regards the cross-over points (also generally known as “under-pass points”), in which there occurs cross-over between two different metal turns of the antenna  42 . With reference to the antenna  42  shown in  FIG. 13   e , it may be likewise possible to provide within the internal portion  43  defined by the metal turns  40 , an additional electrode (not shown), for example having a shape that is the same as that of the aforementioned second portion  50   b  illustrated in  FIG. 10 , and to remove the first metal via  54 . The additional electrode is set in a way coplanar with respect to the antenna  42  and may be coupled in a way in itself known to a point of contact of the antenna  42 , the point of contact being set, for example, on the outermost metal turn  40  of the antenna  42 , in such a way that the antenna  42  is still of a differential type. In this way, an electrical circuit of the type shown in  FIG. 13   f  is obtained, i.e., provided, with respect to what is shown in  FIG. 13   c , with an additional capacitor Cx formed by the additional electrode and by the first electrode  50 . 
         [0054]    An embodiment of the communications device  30  may be tested and calibrated in a convenient way. In particular, as is known, the connection between the capacitor C and the antenna  42  means that the communications device  30  may be optimized for transmitting at a certain resonant frequency, which depends upon the inductance L associated with the antenna  42  and upon the capacitance of the capacitor C, i.e., upon the shape and arrangement of the first and second electrodes  50 ,  52 . The resonant frequency may be measured by means of automatic test equipment (ATE)  102  ( FIG. 14 ) coupled to a transmitter card  104 , which is provided with a support  105  and a respective test antenna  106  set on the support  105 . Operatively, it may be possible to transmit through the test antenna  106   a  querying signal at a test frequency, and receive a corresponding signal of response from the communications device  30 , for example once again by means of the test antenna  106 . By repeating the procedure for different values of the test frequency, and detecting, for example, the amplitudes of the corresponding response signals, it is possible to determine the resonant frequency, equal to the value of the test frequency to which, for example, the response signal with maximum amplitude corresponds. 
         [0055]    As has been mentioned, it may be likewise possible to vary the resonant frequency of the communications device  30 , as shown once again in  FIG. 14 , which illustrates an embodiment in which the second portion  50   b  of the first electrode  50  is coplanar to the antenna  42 . In fact, it may be possible to focus a laser beam W, for example, by means of a lens  108 , in such a way that it will cut the geometrical shape of the second portion  50   b  modifying the geometry (for example, disconnecting a portion), and hence modifying the geometry of the portion  50   b  of the first electrode  50 , with consequent variation of the capacitance of the capacitor C. In this way, also the resonant frequency of the communications device  30  may be varied. In addition, the cutting operation may be performed simultaneously with the aforementioned operations aimed at determining the resonant frequency, for example using a transparent support  105  for the laser beam W, and focusing the laser beam W in such a way that it will traverse the transmitter board  104  before impinging upon the communications device  30 . In this way, it may be possible to verify step by step the effect that operations of change of the shape of the second portion  50   b  have on the resonance frequency. Possibly, the support  105  may have an opening through which the laser beam W may pass. 
         [0056]    Purely by way of example, if we assume that the second portion  50   b  has the shape shown in  FIG. 12 , and hence is formed by the aforementioned plurality of conductive elements  100 , it may be possible to uncouple ohmically one or more of these conductive elements  100  from the turns  40  of the antenna  42 . 
         [0057]    In a way altogether similar, it may be possible to act on at least one element from among: the first and second portions  50   a,    50   b  of the first electrode  50 ; the second electrode  52 ; the third electrode  58 ; and the additional capacitor Cx. For this purpose, it is expedient for these elements to be electromagnetically accessible to the laser beam W. Consequently, the dielectric layer  38  may be at least in part transparent for the laser beam W. 
         [0058]    In order to vary the resonance frequency of the communications device  30 , it may likewise be possible to cause the laser beam W to impinge on the metal turns  40  of the antenna  42 , so as to vary the inductance thereof. 
         [0059]    By way of example,  FIG. 15  shows an embodiment, in which the outermost turn of the antenna  42 , designated by  40   x , has a side  40   k , departing from which are, in a direction orthogonal to the side  40   k  itself, a plurality of conductive segments (also known as “stubs”), each of which terminates coupled ohmically up to a corresponding additional via. By way of example, in  FIG. 15  a first stub, a second stub, a third stub, a fourth stub, and a fifth stub  110   a - 110   e  are shown, which depart from corresponding points of the turn  40   x,  have increasing distances from the innermost point of the metal turns  40  (which is designated by V and coupled to which is, by way of example, the second metal via  56 ), and are, respectively, coupled to a first additional via, a second additional via, a third additional via, and a fourth additional via  112   a - 112   d , and the first metal via  54 . As already described for the first metal via  54 , also the first, second, third, and fourth additional vias  112   a - 112   d  are ohmically coupled to the first electrode  50 , as shown schematically in  FIG. 15 . In the case where the first electrode  50  is formed by the first and second portions  50   a,    50   b  arranged in a non-coplanar way, the first, second, third, and fourth additional vias  112   a - 112   d  contact the first portion  50   a,  which, as has been said, forms the electromagnetic shield  36 . Given the communications device  30 , it may be possible to vary the inductance of the antenna  42  by cutting, with the laser beam W, one or more of the stubs  110   a - 110   d,  starting from the stub  110   a  up to the stub  110   d,  i.e., by ohmically uncoupling one or more from among the first, second, third, and fourth additional vias  112   a - 112   d . For example, in the case where the first, second, third, fourth, and fifth stubs  110   a - 110   e  are all coupled to the side  40   k,  the inductance L of the antenna  42  is proportional to the distance, measured along the metal turns  40 , between the point V and the first additional metal via  112   a.  Instead, if the first metal stub  110   a  is uncoupled from the side  40   k,  the inductance L of the antenna  42  increases in so far as it is proportional to the distance, measured along the metal turns  40 , between the point V and the second additional metal via  112   b,  and so forth. 
         [0060]    As illustrated in  FIG. 16 , an embodiment of the present electronic communications device may be integrated in a communications system  200  formed, not only by at least one single electronic communications device, here designated by  230 , but also by an electronic subsystem  210  (for example, an RFID reader) coupled to a querying antenna  220 , which may transmit and receive data to/from the antenna of the electronic communications device  230 . A communications system of this sort may find wide use, for example, in the field of RFID applications or of so-called Smart Cards. 
         [0061]    Advantages that one or more embodiments of the above-described communications device affords emerge clearly from the foregoing discussion. In practice, it enables reduction of the encumbrance, integrating at least part of the capacitor coupled to the antenna in the electromagnetic shield, without impairing the capacity of the electromagnetic shield to protect the antenna and the integrated circuit underlying the electromagnetic shield itself by mutual interference. 
         [0062]    In addition, one or more embodiments of the present communications device may be calibrated easily, in particular as regards the resonant frequency of the antenna, without any need to resort to probes that ohmically contact the communications device, and hence preventing the risk of damage to the communications device. 
         [0063]    Finally, it is clear that modifications and variations may be made to the communications device described and illustrated herein. 
         [0064]    In the first place, the first and second electrodes  50 ,  52  may couple up to the antenna  42  in such a way that the capacitor C is coupled to the antenna  42  not in parallel, but in series. 
         [0065]    As regards, instead, the shapes of the first and second electrodes  50 ,  52  of the capacitor C, the shapes of possible other electrodes, and possibly the shapes of the first and second portions  50   a,    50   b  of the first electrode  50 , they may differ from what has been described and illustrated so far. In addition, one between the first and second electrodes  50 ,  52  may be coupled to ground. 
         [0066]    Again, the first and second electrodes  50 ,  52 , as likewise the antenna  42 , may be made either totally or in part of polysilicon or other conductive materials (for example metal), materials having ferromagnetic characteristics, such as for example nickel and corresponding alloys, or cobalt and corresponding alloys. For example, the first electrode  50  and/or the second electrode  52 , as well as possible other electrodes, may be formed either totally or in part by a layer of conductive material coated with a layer of ferromagnetic material, or else again they may be made either totally or in part of polysilicon. 
         [0067]    In addition, instead of the first and second metal vias  54 ,  56 , it may be possible to resort to vias of any conductive material, not necessarily metal. 
         [0068]    As regards, in particular, the antenna  42 , it may have a shape different from the ones described. For example, it may comprise two or more ohmically uncoupled conductive elements. Again, it may lie in a number of planes. It is likewise evident that the antenna  42  may be used both for transmitting and for receiving signals. 
         [0069]    Finally, the antenna  42  and the electromagnetic shield  36  of one or more embodiments of the present communications device  30  may be provided, in a non-integrated form, on a support/substrate, such as, for example, a printed-circuit board, and be coupled, for example, through conductive bumps to an integrated electronic device set on the support/substrate. 
         [0070]    It may likewise be possible for the support/substrate to be coupled to an additional antenna (not shown), for example set specular to the antenna  42  with respect to the electromagnetic shield  36 , and hence underneath the electromagnetic shield  36 , to which the additional antenna is coupled in a way similar to what has been described as regards the antenna  42 . 
         [0071]    From the foregoing it will be appreciated that, although specific embodiments have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the disclosure. Furthermore, where an alternative is disclosed for a particular embodiment, this alternative may also apply to other embodiments even if not specifically stated.