WO2014198998A1

WO2014198998A1 - A shielding apparatus and method of providing a shielding apparatus

Info

Publication number: WO2014198998A1
Application number: PCT/FI2013/050629
Authority: WO
Inventors: Juha Backman; Tuomas TALJA
Original assignee: Nokia Corporation
Priority date: 2013-06-10
Filing date: 2013-06-10
Publication date: 2014-12-18

Abstract

A shielding apparatus, method for providing a shielding apparatus and electronic device comprising a shielding apparatus where the shielding apparatus comprises: a shield layer (3) comprising one or more discontinuities; and one or more covering portions (5, 7) where the one or more covering portions (5, 7) are provided over the discontinuities; wherein the one or more covering portions (5,7) are capacitively coupled to the shield layer (3).

Description

TITLE

A Shielding Apparatus and Method of Providing a Shielding Apparatus TECHNOLOGICAL FIELD

Embodiments of the present invention relate to a shielding apparatus and method of providing a shielding apparatus. In particular, they relate to a shielding apparatus and method of providing a shielding apparatus for shielding electronic components from electromagnetic fields.

BACKGROUND

Apparatus such as shielding apparatus may prevent leakage of electromagnetic fields between electronic components. The shielding apparatus may comprise a metal layer. The fluctuating electromagnetic fields may induce eddy currents in the metal layer which may cause heating of the shielding apparatus.

The heating of the metal layer may be undesirable. Therefore it would be desirable to provide an improved shielding apparatus.

BRIEF SUMMARY

According to various, but not necessarily all, examples of the disclosure there may be provided a shielding apparatus comprising: a shield layer comprising one or more discontinuities; and one or more covering portions where the one or more covering portions are provided over the discontinuities; wherein the one or more covering layers are capacitively coupled to the shield layer.

In some examples the discontinuities may be configured to divide the shield layer into small areas to inhibit induced current in the shield layer.

In some examples the discontinuities may comprise gaps in the shield layer. The gaps may be air filled. In some examples the discontinuities may comprise a portion of a non-conductive substrate which is not covered with a conductive material.

In some examples a plurality of discontinuities may be provided.

In some examples the discontinuities may be configured to divide the shield layer into a plurality of spatially separated portions.

In some examples the shield layer may comprise a conductive metal.

In some examples the covering portions may be configured to completely cover the discontinuities. The covering portions may also be configured to cover a portion of the shield layer. The covering portions may extend over a portion of the shield layer to enable capacitive coupling between the covering portion and the shield layer.

In some examples the covering portion may comprise a metal layer.

In some examples the shielding apparatus may comprise a radio frequency shielding apparatus.

According to various, but not necessarily all, examples of the disclosure there may be provided a module comprising a shielding apparatus as described above.

According to various, but not necessarily all, examples of the disclosure there may be provided an electronic communications device comprising a shielding apparatus as described above.

According to various, but not necessarily all, examples of the disclosure there may be provided a method for providing a shielding apparatus comprising: providing a shield layer comprising one or more discontinuities; and providing one or more covering portions where the one or more covering portions are provided over the discontinuities; wherein the one or more covering portions are capacitively coupled to the shield layer. In some examples the discontinuities may be configured to divide the shield layer into small areas to inhibit induced current in the shield layer.

In some examples the discontinuities may comprise gaps in the shield layer.

In some examples the gaps may be air filled.

In some examples the discontinuities may comprise a portion of a non-conductive substrate which is not covered with a conductive material.

In some examples a plurality of discontinuities may be provided.

In some examples the shield layer may comprise a conductive metal.

In some examples the covering portions may be configured to completely cover the discontinuities. The covering portions may also be configured to cover a portion of the shield layer.

In some examples the covering portions may cover a portion of the shield layer to enable capacitive coupling between the covering portion and the shield layer. In some examples the covering portion may comprise a metal layer.

In some examples the shielding apparatus may comprise a radio frequency shielding apparatus. The apparatus may be for shielding electronic components disposed within the apparatus from electromagnetic fields which are generated external to the apparatus. In addition or alternatively, the apparatus may be for preventing radiated emissions of electromagnetic fields, generated by one or more component within the apparatus, from being radiated external to the apparatus. The apparatus may be provided within an electronic device. The electronic device may be for wireless communication.

BRIEF DESCRIPTION

For a better understanding of various examples that are useful for understanding the detailed description, reference will now be made by way of example only to the accompanying drawings in which:

Fig. 1 illustrates a shielding apparatus;

Figs. 2A to 2E illustrate shield layers;

Figs. 3A to 3D illustrate a plan view of a shielding apparatus;

Figs. 4A to 4C illustrate a cross section through a shielding apparatus;

Figs. 5A to 5C illustrate a shielding apparatus;

Fig. 6 is a plot of radiated power for the shielding apparatus of Figs. 5A to 5C;

Figs. 7A and 7B are plots of temperature of shielding apparatus;

Fig. 8 is a flow diagram for a method of providing a shielding apparatus.

DETAILED DESCRIPTION The Figures illustrate a shielding apparatus 1 comprising: a shield layer 3 comprising one or more discontinuities 23; and one or more covering portions 5 where the one or more covering portions 5 are provided over the discontinuities 23; wherein the one or more covering portions 5 are capacitively coupled to the shield layer 3. Fig. 1 schematically illustrates a shielding apparatus 1 according to an example of the disclosure.

The shielding apparatus 1 may be provided within an electronic device 10. The electronic device 10 may be a device such as a portable electronic communications device. The electronic device 10 may comprise components which may generate electromagnetic fields. For example a portable communication device may comprise components such as inductive charging components, antennas, audio components and vibra components which comprise coils or other conductive structures which generate electromagnetic fields. The shielding apparatus 1 may be provided adjacent to such components to protect other components within the electronic device 10 from the generated electromagnetic fields. In some examples the shielding apparatus 1 may surround the components which generate the electromagnetic fields. Some components or some of the other components may be electronic, mechanical, electromagnetic or electro-mechanical components. Some mechanical components may radiate or re-radiate electromagnetic fields unintentionally.

In the example of Fig. 1 the shielding apparatus 1 is provided on a circuit board 1 1 . The circuit board 1 1 may be a printed circuit board (PCB). The components (not illustrated in Figure 1 ) of the electronic device 10 may be mounted on and/or coupled to the circuit board 1 1 . In some examples the circuit board 1 1 may act as a ground plane for components of the electronic device 10. In some examples, the components may be one or more electronic component, and not limited to any of the following types of electronic component : audio frequency, baseband frequency or radio frequency (RF) components comprising one or more of an inductor, capacitor, resistor, transmission line (microstrip/stripline/co-planar waveguide), integrated circuit (IC), transistor, diode, connector, switch, filter, duplexer, diplexer, memory, processor, and logic gate.

In the example of Fig. 1 the shielding apparatus 1 comprises a shield layer 3, a plurality of covering portions 5 and an insulating layer 7.

The shield layer 3 may be configured to provide a shield for electromagnetic fields for electronic components on the circuit board 1 1 . The shield layer 1 1 may be configured to act as a barrier to prevent leakage of electromagnetic fields. The shield layer 3 may comprise a highly conductive material. The shield layer 3 may comprise a conductive metal such as copper or any other suitable material. The shield layer 3 may comprise a thin layer. The shield layer 3 may comprise a thin metal layer. The shield layer 3 may be thin such that the thickness of the shield layer 3 is much less than other dimensions, such as the length, of the shield layer 3. In some examples the shield layer 3 may be thin such that the thickness of the shield layer 3 is several orders of magnitude less than other dimensions, such as the length, of the shield layer 3. The shield layer 3 may comprise a thin layer in the order of between 0.1 and 1 mm thickness, but other thicknesses are also possible.

In the example of Fig. 1 a plurality of covering portions 5 are provided overlaying the shield layer 3. The covering portions 5 may be arranged so that they cover, in other words overlie, discontinuities in the shield layer 3. The discontinuities are not shown in Fig. 1 but examples are described below.

The covering portions 5 may also comprise a highly conductive material such as copper or any other suitable material. The covering portions 5 may also comprise a thin layer. The covering portions 5 may be thin such that the thickness of the covering portions 5 is much less than other dimensions, such as the length, of the covering portions 5. In some examples the covering portions 5 may be thin such that the thickness of the covering portions 5 is several orders of magnitude less than other dimensions, such as the length, of the covering portions 5.

In the example of Fig. 1 an insulating layer 7 is provided between the covering portions 5 and the shield layer 3. The insulating layer 7 may comprise any suitable material such as air, an adhesive and/or dielectric material. The insulating layer 7 may be configured to enable capacitive coupling between the shield layer 3 and the covering portions 5. The insulating layer 7 may comprise two or more separate spacing members forming a non-homogeneous layer, where the spacing members may comprise an adhesive and/or dielectric material and the spacing members are surrounded by air so that the spacing members do not contact each other.

Although in the example embodiments a separate shielding component or module is illustrated it should be appreciated that in other example embodiments that the one or more sub-parts of a shielding component described in the example embodiments may be adjoining or abutting another component of the electronic device 10. Alternatively, one or more sub-parts of a shielding component described in the example embodiments may be provided by another part or component of the electronic device 10, for example, and not limited to, at least a portion of a layer of a printed circuit board, at least a portion of a conductive structure (for example, a conductive housing of the electronic device 10), and at least a portion of a conductive component (for example, a conductive portion of a touch display).

Figs. 2A to 2E illustrate plan views of shield layers 3 and illustrate examples of discontinuities 23 which may be covered by the covering portions 5. The example shield layers 3 of Figs. 2A to 2E may be the same size as each other. It is to be appreciated that the size of the shield layers 3 used may depend on factors such as the space available on the circuit board 1 1 .

In Fig. 2A the shield layer 3 comprises a solid sheet. The shield layer 3 does not comprise any discontinuities. The shield layer 3 comprises a square. In other examples other shapes of shield layer 3 may be provided. For example, the shield layer 3 may be a rectangle, circle, oval or any other suitable regular or irregular shape.

The arrow 21 indicates the eddy currents which may be generated in the shield layer 3 by a fluctuating electromagnetic field. As the shield layer 3 of Fig. 2A comprises a solid sheet a large surface area is available for the paths of the eddy currents and so a large eddy current may be generated.

In the example of Fig. 2B the shield layer 3 is also substantially square however, two discontinuities 23 are provided in the shield layer 3. The discontinuities 23 may comprise gaps in the shield layer 3. The gaps may be filled with air. In some examples the gaps may be filled with other materials. In some examples the gaps may be filled with both air and one or more other material. The materials filling the gaps may be insulating materials so that no eddy currents are induced in the gap.

In the example of Fig. 2B two discontinuities 23 are provided. The discontinuities 23 are provided as cut out portions in the side of the shield layer 3. The cut out portions extend at least one third of the way into the width of the shield layer 3. The two discontinuities 23 divide the surface of the shield layer 3 into two lobes 25. In the example of Fig. 2B the lobes 25 are of equal or approximately equal size. In Fig. 2B the arrows 21 indicate the eddy currents which may be generated in the shield layer 3 by a fluctuating electromagnetic field. As the shield layer 3 of Fig. 2B has been divided into two lobes 25 by the discontinuities 23 this reduces the area available for the generation of the eddy currents. The eddy currents generated in the shield layer 3 of Fig. 2B are smaller than the eddy currents generated in the shield layer 3 of Fig. 2A.

In the example of Fig. 2C the shield layer 3 is also substantially square however, four discontinuities 23 are provided in the shield layer 3. The discontinuities 23 in the example of Fig. 2C may be the same as the discontinuities in the example of Fig. 2B. The discontinuities 23 may comprise gaps in the shield layer 3. The gaps may be filled with air. In some examples the gaps may be filled with other materials. The materials filling the gaps may be insulating materials so that no eddy currents are induced in the gap.

In Fig. 2C four discontinuities 23 are provided. In Fig. 2C a discontinuity 23 is provided in each side of the shield layer 3. The discontinuities 23 are provided as cut out portions in the sides of the shield layer 3. The cut out portions extend at least one third of the way into the width of the shield layer 3. In the example of Fig. 2C the four discontinuities 23 divide the surface of the shield layer 23 into four lobes 25. In the example of Fig. 2C each of the lobes 25 are of equal or approximately equal size.

In Fig. 2C the arrows 21 indicate the eddy currents which may be generated in the shield layer 3 by a fluctuating electromagnetic field. As the shield layer 3 of Fig. 2C has been divided into four lobes 25 by the discontinuities 23 this further reduces the area available for the generation of the eddy currents. The eddy currents generated in the shield layer 3 of Fig. 2C are smaller than the eddy currents generated in the shield layer 3 of Figs. 2B and 2A.

The shield layers 3 and the discontinuities 23 of Figs. 2A to 2C are not drawn to scale. In some examples the shield layer 3 may have side lengths of 2-3 cm. In such examples the discontinuities 23 may have a width of approximately 1 mm. The discontinuities 23 may extend at least one third of the way into the side of the shield layer 3. That is, for a shield layer 3 having side lengths of 3 cm the discontinuities may extend at least 1 cm into the shield layer 3. It is to be appreciated that shield layers 3 of any suitable size may be used and the size and shape of the discontinuities 23 may be changed accordingly. It is to be appreciated that lobes 25 may also be of any suitable size and shape and may not be the same size or shape as one another when disposed in one or more shield layer 3.

In the example of Figs. 2D and 2E the shield layer 3 may comprise a conductive coating provided on a non-conductive substrate. The conductive coating may comprise any suitable material such as a foil layer or evaporated layers. In such examples the discontinuities 23 may comprise a portion of the non-conductive substrate which is not covered with the conductive coating. This may allow the conductive portions of the shield layer 3 to be spatially separated from each other. In the example of Fig. 2D the shield layer 3 is also substantially square. A single discontinuity 23 is provided in the shield layer 3. In Fig. 2D the discontinuity 23 extends from one side of the shield layer 3 to an opposite side of the shield layer 3. The single discontinuity 23 divides the conductive portion of the shield layer 3 into two spatially separated portions 31 .

In the example of Fig. 2D the discontinuity 23 is provided at the midpoint or approximately at the midpoint of the side of the shield layer 3 so that the spatially separated portions 31 are the same size or substantially the same size as each other.

In Fig. 2D the arrows 21 indicate the eddy currents which may be generated in the shield layer 3 by a fluctuating electromagnetic field. As the shield layer 3 of Fig. 2D comprises two spatially separated conductive portions 31 this reduces the area available for the generation of the eddy currents. The eddy currents 21 generated in the shield layer 3 of Fig. 2D are smaller than the eddy currents 21 generated in the shield layer 3 of Fig. 2A. As the conductive portions 31 of the shield layer 3 are spatially separated from each other there may be smaller eddy currents in the shield layer 3 of Fig. 2D than the shield layer of Fig. 2B. In the example of Fig. 2E the shield layer 3 is also substantially square. In the example of Fig. 2E a single discontinuity 23 is provided. In Fig. 2E the discontinuity 23 is cross shaped and divides the shield layer 3 into four spatially separated conductive portions 31 .

In Fig. 2E the cross shaped discontinuity 23 extends from each side of the shield layer 3 to the opposite side of the shield layer 3. In the example of Fig. 2E the discontinuity 23 is provided at the midpoint or approximately at the midpoint of the side of the shield layer 3. The spatially separated portions 31 of the shield layer 3 are the same size or substantially the same size as each other.

In Fig. 2E the arrows 21 indicate the eddy currents which may be generated in the shield layer 3 by a fluctuating electromagnetic field. As the shield layer 3 of Fig. 2E comprises four spatially separated portions 31 this reduces the area available for the generation of the eddy currents. The eddy currents 21 generated in the shield layer 3 of Fig. 2E are smaller than the eddy currents 21 generated in the shield layer 3 of Fig. 2A and Fig. 2D. As the conductive portions of the shield layer 3 are spatially separated from each other there may be smaller eddy currents in the shield layer 3 of Fig. 2E than the shield layer of Fig. 2C.

Figs. 3A to 3D are plan views of shield apparatus 1 according to examples of the disclosure. The shield apparatus 1 comprises a shield layer 3 comprising one or more discontinuities 23 and covering portions 5. In Figs. 3A to 3D the dotted lines indicate the discontinuities 23 in the shield layer 3 and the dashed lines indicate the covering portions 5.

An insulating layer 7 may be provided between the covering portions 5 and the shield layer 3, as described above in relation to Fig. 1 . The insulating layer 7 is provided underneath the covering portions 5 and so is not visible in the views of Figs. 3A to 3D.

In each of Figs. 3A to 3D the shield layer 3 is square or substantially square. The discontinuities 23 are configured, as described below, to divide the shield layer 3 into small areas to inhibit induced current in the shield layer 3. In Fig. 3A two discontinuities 23 are provided. In the example of Fig. 3A the discontinuities 23 are provided as cut out portions in the side of the shield layer 3. The cut out portions extend at least one third of the way into the width of the shield layer 3. The two discontinuities 23 divide the surface of the shield layer 3 into two lobes 25. In the example of Fig. 3A the lobes 25 are of equal or approximately equal size.

Two covering portions 5 are provided. The covering portions 5 extend over the discontinuities 23. Each of the covering portions 5 extend over one of the discontinuities 23. In the example of Fig. 3A the covering portions 5 completely cover the discontinuities 23. This may reduce leakage of electromagnetic field through the discontinuity 23 in the shield layer 3.

In the example of Fig. 3A the covering portion 5 also extends over a portion of the shield layer 3. The covering portion 5 may extend over enough of the shield layer 3 to enable capacitive coupling between the shield layer 3 and the covering portion 5. In some examples the covering portion 5 may extend over 2-3 mm of the shield layer 3 around the edges of the discontinuity 23.

In the example of Fig. 3A the two covering portions 5 are physically separate from each other. The covering portions 5 may be configured so that there is no direct current path between the two covering portions 5. The covering portions 5 may be configured so that no direct current can flow directly between the two covering portions 5. This may reduce the amount of eddy currents induced in the covering portions 5.

In Fig. 3B four discontinuities 23 are provided. The discontinuities 23 are provided as cut out portions in the side of the shield layer 3 which extend at least one third of the way into the width of the shield layer 3. The four discontinuities 23 divide the surface of the shield layer 3 into four lobes 25. In the example of Fig. 3B the lobes 25 are of equal or approximately equal size. The shield layers 3 and the discontinuities 23 in Figs. 3A and 3B are similar to those of Figs. 2B and 2C. It is to be appreciated that the eddy currents induced in the shield layers would also be similar. In Fig. 3B four covering portions 5 are provided. The covering portions 5 extend over the discontinuities 23. Each of the covering portions 5 extend over one of the discontinuities 23. In the example of Fig. 3B the covering portions 5 completely cover the discontinuities 23. This may reduce leakage of electromagnetic field through the discontinuity 23 in the shield layer 3.

The covering portions 5 also extend over a portion of the shield layer 3. The covering portions 5 may extend over enough of the shield layer 3 to enable capacitive coupling between the shield layer 3 and the covering portion 5. In some examples the covering portions 5 may extend over 2-3 mm of the shield layer 3 around the edges of the discontinuity 23.

In the example of Fig. 3B the two covering portions 5 are physically separate from each other. The covering portions 5 may be configured so that there is no direct current path between the covering portions 5. The covering portions 5 may be configured so that no direct current can flow directly between the covering portions 5. This may reduce the amount of eddy currents induced in the covering portions 5.

In Fig. 3C a single discontinuity 23 is provided in the shield layer 3. The discontinuity 23 may comprise a section of a non-conductive substrate which is not covered by a conductive material. In Fig. 3C the discontinuity 23 extends from one side of the shield layer 3 to an opposite side of the shield layer 3. The single discontinuity 23 divides the shield layer 3 into spatially separated portions 31 .

In Fig. 3C the portions 31 of the shield 3 are spatially separated from each other. The discontinuity 23 may be such that there is no direct current path between the spatially separated portions 31 of the shield layer 3. The spatially separated portions 31 of the shield layer 3 may be configured so that no direct current flows between the spatially separated portions 31 . In the example of Fig. 3C the discontinuity 23 is provided at the midpoint or approximately at the midpoint of the side of the shield layer 3. The spatially separated portions 31 are the same size or substantially the same size as each other.

In Fig. 3C a single covering portion 5 extends over the discontinuity 23. As described above the the covering portion 5 may completely cover the discontinuity 23 to reduce leakage of electromagnetic field through the discontinuity 23. The covering portion 5 may also extend over a portion of the shield layer 3 to enable capacitive coupling between the shield layer 3 and the covering portion 5.

Fig. 3D illustrates another example in which a single discontinuity 23 is provided. In the example of Fig. 3D the discontinuity 23 is cross shaped and divides the shield layer 3 into four spatially separated portions 31 . The discontinuity 23 may be such that there is no direct current path between the spatially separated portions 31 of the shield layer 3. The spatially separated portions 31 of the shield layer 3 may be configured so that no direct current flows between the spatially separated portions 31 . In Fig. 3D the cross shaped discontinuity 23 extends from each side of the shield layer 3 to the opposite side of the shield layer 3. In the example of Fig. 3D the discontinuity 23 is provided at the midpoint or approximately at the midpoint of the side of the shield layer 3. The spatially separated portions 31 are the same size or substantially the same size as each other.

In Fig. 3D three covering portions 5 extend over the discontinuity 23. As described above the covering portions 5 may completely cover the discontinuity 23 to reduce leakage of electromagnetic field through the discontinuity 23. The covering portions 5 may also extend over a portion of the shield layer 3 to enable capacitive coupling between the shield layer 3 and the covering portion 5. The covering portions 5 may be insulated from each other to prevent direct current flow between the covering portions 5.

Figs. 4A to 4C illustrate examples of the covering portion 5 which may be used. In Fig. 4A the covering portion 5 comprises a conductive plate 41 . The conductive plate 41 may comprise a single layer of conductive material such as metal. The conductive material may be any suitable material such as copper. Although the conductive plate 41 is illustrated as a flat conductive sheet it should be appreciated that in other examples the conductive plate 41 may take any two or three dimensional shape or form.

The conductive plate 41 may be separated from the shield layer 3 by an insulating layer 7. The insulating layer 7 may comprise a dielectric material. The dielectric layer 7 may be provided in a thin layer. The dielectric layer 7 may be thin such that the thickness of the dielectric layer 7 is significantly less than other dimensions of the dielectric layer 7.

The insulating layer 7 may be configured to enable capacitive coupling between the shield layer 3 and the covering portion 5. The insulating layer 7 may be configured to prevent direct current flow between the shield layer 3 and the covering portion 5.

In Fig. 4B the covering portion 5 comprises an array of capacitors 43 which extend over the discontinuity 23. The array of capacitors 43 may be surface mounted on the shield layer 3. A solder or conductive adhesive 45 may also be provided to secure the array of capacitors 43 to the shield layer 3.

In Fig. 4C the covering portion 5 may comprise a multilayer capacitor 47 which may extend over the discontinuity 23. The multilayer capacitor 47 may be surface mounted to the shield layer 3.

Figs. 5A to 5C illustrate different geometries of shield apparatus 1 . The results of tests using these geometries are provided in Figs. 6 and 7A to 7B. In Fig. 5A the shield layer 3 comprises a sheet of copper with no discontinuities 23 and no cover layer 5. The copper had thickness 0.2 mm, width 2 cm and length 2 cm. The height of the shield layer 3 was 2 mm. For the purpose of testing a short wire protruding above a perfectly conducting ground plane at the end of a terminated coaxial cable 24 was also provided. The short wire was modelled as an open circuit coaxial cable 24 by not terminating the inner conductor.

In Fig. 5B the shield layer 3 comprises a sheet of copper with four discontinuities 23 but no covering portions 5. As in Fig. 5A the copper had thickness 0.2 mm, width 2 cm and length 2 cm and the height of the shield layer 3 was 2 mm. The discontinuities 23 had a length of 7.5 mm and a width of 0.5 mm.

In Fig. 5C the shield layer 3 also comprises a sheet of copper with four discontinuities 23 however in Fig. 5C covering portions 5 are provided over each of the discontinuities 23. As in Figs. 5A and 5B the copper had thickness 0.2 mm, width 2 cm and length 2 cm and the height of the shield layer 3 was 2 mm and the discontinuities 23 had a length of 7.5 mm and a width of 0.5 mm. Four covering portions 5 were provided. Each of the covering portions 5 comprises a sheet of copper 0.2 mm thick and 4 mm wide. The covering portions 5 were arranged so that there was a 0.2 mm air gap between the shield layer 3 and the covering portion 5.

Fig. 6 illustrates a plot of radiated power over a frequency range from 10 kHz to 5 GHz for four different test configurations. The power radiated from the short wire was computed. The radiated power gives a measure of the shielding performance of the shielding apparatus 1 .

In the first configuration the coaxial cable 24 was uncovered (plot D). In the second configuration the coaxial cable 24 was covered with a solid sheet of copper as illustrated in Fig. 5A (plot A). In the third configuration the coaxial cable 24 was covered with a sheet of copper with discontinuities 23 as illustrated in Fig. 5B (plot B). In the fourth configuration the coaxial cable 24 was covered with a sheet of copper with discontinuities where the discontinuities where covered with covering portions 5 as illustrated in Fig. 6C (plot C).

The plot of Fig. 6 indicates that covering the discontinuities 23 with the covering portions 5 gives almost as good performance as an electromagnetic shield between the frequencies of 1 -10 MHz as the solid sheet. This may enable the shield apparatus of Fig. 5C, or other similar configurations, to be used as a radio frequency shielding apparatus.

Figs. 7A and 7B provide plots of the temperature increases for the respective shield layers. Plot 1 in Fig. 7A is the solid shield as illustrated in Fig. 5A and plot 2 in Fig. 7A is the shield with two discontinuities 23 this shows a small decrease in the temperature of the shield.

In Fig. 7B plot 1 is also the solid shield as illustrated in Fig. 5A while plot 2 is a shield with four discontinuities as illustrated in Fig. 5C. This shows a significant decrease in the temperature of the shield compared to the solid sheet example.

Fig. 8 illustrates a method according to examples of the disclosure. The method comprises, at block 81 , providing a shield layer 3 comprising one or more discontinuities 23. The shield layer 3 and the discontinuities 23 may be provided in the configurations as described above. The method also comprises, at block 83, providing one or more covering portions 5 where the one or more covering portions 5 are provided over the discontinuities 23. The covering portions 5 may be capacitively coupled to the shield layer 3. The covering portions 5 may be also be provided in the configurations described above.

The shield apparatus 1 as described above provide for reduced heating of the shield layer 3 due to the discontinuities provided. The covering portions 5 which are capacitively coupled to the shield layer 3 act to reduce the leakage of the electromagnetic field through the discontinuities 23 and so make the apparatus 1 effective as a barrier to electromagnetic fields. However as the covering portions 5 are capacitively coupled to the shield layer this does not cause any additional eddy currents. As used here 'module' refers to a unit or apparatus that excludes certain parts/components that would be added by an end manufacturer or a user.

In the description, the wording 'connect' and 'couple' and their derivatives mean operationally connected or coupled. It should be appreciated that any number or combination of intervening components can exist (including no intervening components). Additionally, it should be appreciated that the connection or coupling may be a physical galvanic connection and/or an electromagnetic connection. A galvanic connection may provide a direct current path and/or enable direct current flow. An electromagnetic connection may enable a current to be induced between physically separated components.

The blocks illustrated in Fig. 8 may represent steps in a method and/or sections of code in a computer program. The illustration of a particular order to the blocks does not necessarily imply that there is a required or preferred order for the blocks and the order and arrangement of the blocks may be varied. Furthermore, it may be possible for some blocks to be omitted.

The term "comprise" is used in this document with an inclusive not an exclusive meaning. That is any reference to X comprising Y indicates that X may comprise only one Y or may comprise more than one Y. If it is intended to use "comprise" with an exclusive meaning then it will be made clear in the context by referring to "comprising only one..." or by using "consisting". In this description, reference has been made to various examples. The description of features or functions in relation to an example indicates that those features or functions are present in that example. The use of the term "example" or "for example" or "may" in the text denotes, whether explicitly stated or not, that such features or functions are present in at least the described example, whether described as an example or not, and that they can be, but are not necessarily, present in some of or all other examples. Thus "example", "for example" or "may" refers to a particular instance in a class of examples. A property of the instance can be a property of only that instance or a property of the class or a property of a subclass of the class that includes some but not all of the instances in the class.

Although embodiments of the present invention have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the invention as claimed. For example, in the examples described above, up to four discontinuities 23 are provided in the shield layer 3. It is to be appreciated that the number and/or size and/or shape of the discontinuities 23 may depend on factors such as the material of the shield layer 3, the structural integrity of the shield layer 3 the size and shape of the shield layer 3 and other factors.

Features described in the preceding description may be used in combinations other than the combinations explicitly described.

Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not.

Although features have been described with reference to certain embodiments, those features may also be present in other embodiments whether described or not. Whilst endeavoring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon. l/we claim:

Claims

1 . A shielding apparatus comprising:

a shield layer comprising one or more discontinuities; and

one or more covering portions where the one or more covering portions are provided over the discontinuities; wherein

the one or more covering layers are capacitively coupled to the shield layer.

2. A shielding apparatus as claimed in claim 1 wherein the discontinuities are configured to divide the shield layer into small areas to inhibit induced current in the shield layer.

3. A shielding apparatus as claimed in any preceding claim wherein the discontinuities comprise gaps in the shield layer.

4. A shielding apparatus as claimed in claim 3 wherein the gaps are air filled.

5. A shielding apparatus as claimed in any of claims 1 to 2 wherein the discontinuities comprise a portion of a non-conductive substrate which is not covered with a conductive material.

6. A shielding apparatus as claimed in any preceding claim wherein a plurality of discontinuities are provided.

7. A shielding apparatus as claimed in any preceding claim wherein the discontinuities are configured to divide the shield layer into a plurality of spatially separated portions.

8. A shielding apparatus as claimed in any preceding claim wherein the shield layer comprises a conductive metal.

9. A shielding apparatus as claimed in any preceding claim wherein the covering portions are configured to completely cover the discontinuities.

10. A shielding apparatus as claimed in claim 9 wherein the covering portions are configured to also cover a portion of the shield layer.

1 1 . A shielding apparatus as claimed in claim 10 wherein the covering portions extend over a portion of the shield layer to enable capacitive coupling between the covering portion and the shield layer.

12. A shielding apparatus as claimed in any preceding claim wherein the covering portion comprises a metal layer.

13. A shielding apparatus as claimed in any preceding claim wherein the shielding apparatus comprises a radio frequency shielding apparatus.

14. A module comprising a shielding apparatus as claimed in any preceding claim.

15. An electronic communications device comprising a shielding apparatus as claimed in any of claims 1 to 13.

16. A method for providing a shielding apparatus comprising:

providing a shield layer comprising one or more discontinuities; and

providing one or more covering portions where the one or more covering portions are provided over the discontinuities; wherein

the one or more covering portions are capacitively coupled to the shield layer.

17. A method as claimed in claim 16 wherein the discontinuities are configured to divide the shield layer into small areas to inhibit induced current in the shield layer.

18. A method as claimed in any of claims 16 to 17 wherein the discontinuities comprise gaps in the shield layer.

A method as claimed in claim 18 wherein the gaps are air filled

20. A method as claimed in any of claims 16 to 17 wherein the discontinuities comprise a portion of a non-conductive substrate which is not covered with a conductive material.

21 . A method as claimed in any of claims 16 to 20 wherein a plurality of discontinuities are provided.

22. A method as claimed in any of claims 16 to 21 wherein the discontinuities are configured to divide the shield layer into a plurality of spatially separated portions.

23. A method as claimed in any of claims 16 to 22 wherein the shield layer comprises a conductive metal.

24. A method as claimed in any of claims 16 to 23 wherein the covering portions are configured to completely cover the discontinuities.

25. A method as claimed in claim 24 wherein the covering portions are configured to also cover a portion of the shield layer.

26. A method as claimed in claim 25 wherein the covering portions cover a portion of the shield layer to enable capacitive coupling between the covering portion and the shield layer.

27. A method as claimed in any of claims 16 to 26 wherein the covering portion comprises a metal layer.

28. A method as claimed in any of claims 16 to 27 wherein the shielding apparatus comprises a radio frequency shielding apparatus.