GB2523369A

GB2523369A - A transmission line and a method of manufacturing a transmission line

Info

Publication number: GB2523369A
Application number: GB1403151.2A
Authority: GB
Inventors: Tapani Von-Rauner; Esa-Sakari Maatta
Original assignee: Nokia Technologies Oy
Current assignee: Nokia Technologies Oy
Priority date: 2014-02-24
Filing date: 2014-02-24
Publication date: 2015-08-26
Also published as: GB201403151D0

Abstract

An apparatus comprising a support comprising a channel 20 and a transmission line 30 comprising a signal line 4, a first conductive portion 6, and a second conductive portion 8, wherein the signal line 4 is positioned between the first conductive portion 6 and the second conductive portion 8 and is electrically isolated from the first conductive portion and the second conductive portion; wherein the signal line 4 is aligned with the channel. Aspects of the invention include the module 40 comprising a dielectric substrate 42 that separates the first conductive portion and the signal line. The support 10 may be formed from a metal or metal alloy and the channel 20 is a channel formed in the metal which provides the second conductive portion 8. In other aspects, the support 10 comprises a chassis with a metal coating, where the metal coating provides the second conductive portion 8. The use of channel 20 in support 10 and the alignment of signal line 4 of the transmission line 30 with the channel 20 enables the transmission line 30 to have a low-profile.

Description

TITLE

A Transmission Line and a Method of Manufacturing a Transmission Line

TECHNOLOGICAL FIELD

Embodiments of the present invention relate to a transmission line and/or a method of manufacturing a transmission line. In particular, they relate to a transmission line comprising a signal line and a first conductive portion and a second conductive portion, wherein the signal line is positioned between the first conductive portion and the second conductive portion.

BACKGROUND

A transmission line is a waveguide designed for the transfer of electromagnetic waves.

A coaxial cable is one form of transmission line. It comprises a signal line and a surrounding conductor.

In contrast, a stripline transmission line comprises a signal line, a first conductive portion and a second conductive portion, wherein the signal line is positioned between the first conductive portion and the second conductive portion and is electrically isolated from the first conductive portion and the second conductive portion.

BRIEF SUMMARY

According to various, but not necessarily all, embodiments of the invention there is provided an apparatus comprising: a support comprising a channel; and a transmission line comprising a signal line, a first conductive portion, and a second conductive portion, wherein the signal line is positioned between the first conductive portion and the second conductive portion and is electrically isolated from the first conductive portion and the second conductive portion; wherein the signal line is aligned with the channel.

According to various, but not necessarily all, embodiments of the invention there is provided method comprising: interconnecting a module and a support to form a transmission line, wherein the module comprises a signal line and a first conductive portion, and wherein the support comprises a channel and a second conductive portion, and wherein the transmission line comprises the signal line, the first conductive portion and the second conductive portion, wherein the signal line is positioned between the first conductive portion and the second conductive portion and is electrically isolated from the first conductive portion and the second conductive portion, and wherein the signal line is aligned with the channel.

According to various, but not necessarily all, embodiments of the invention there is provided examples as claimed in the appended claims.

According to various, but not necessarily all, embodiments of the invention there is provided an apparatus comprising: support means comprising a channel; and transmission line means comprising a signal line, a first conductive portion, and a second conductive portion, wherein the signal line is positioned between the first conductive portion and the second conductive portion and is electrically isolated from the first conductive portion and the second conductive portion; wherein the signal line is aligned with the channel.

BRIEF DESCRIPTION

For a better understanding of various examples that are useful for understanding the brief description, reference will now be made by way of example only to the accompanying drawings in which: Figs. 1A and 13 illustrate an example of manufacturing an apparatus comprising a transmission line; Fig. 2 illustrates an example of an apparatus comprising a transmission line; Fig. 3 illustrates another example of an apparatus comprising a transmission line; Fig. 4 illustrates a further example of an apparatus comprising a transmission line; Fig. 5 illustrates a transmission line interconnecting signalling circuitry and interface circuitry; Fig. 6 illustrates a transmission line interconnecting radio frequency circuitry and an antenna; Figs. 7A, 7B and 7C illustrate an example where a support, comprising a channel, is an exterior housing of an electronic device; Fig. 8 illustrates an apparatus comprising a transmission line as illustrated in Fig. lB and a transmission line as illustrated in Fig. 4; Fig. 9 illustrates an apparatus comprising a transmission line comprising multiple signal lines; and Figs 1OA and lOB illustrate complementary signal lines including a positive signal line and a negative signal line respectively.

DETAILED DESCRIPTION

The following description describes examples of a low-profile transmission line 30 which can be integrated within an apparatus 2. The transmission line 30 provides good performance without occupying the volume of a co-axial cable.

The use of a channel 20 in a support 10 and the alignment of a signal line 4 of the transmission line 30 with the channel 20 enables the transmission line 30 to have a low-profile.

The following figures illustrate an apparatus 2 comprising: a support 10 comprising a channel 20; and a transmission line 30 comprising a signal line 4, a first conductive portion 6, and a second conductive portion 8, wherein the signal line 4 is positioned between the first conductive portion 6 and the second conductive portion 8 and is electrically isolated from the first conductive portion 6 and the second conductive portion 8; wherein the signal line 4 is aligned with the channel 20.

Figs. 1A and lB illustrate the manufacture of an apparatus 2. Fig. 1A illustrates a module 40 comprising a signal line 4 and a first conductive portion 6. The figure also illustrates a support 10 comprising a channel 20 and a second conductive portion 8.

The method comprises interconnecting the module 40 and the support 10 to form a transmission line 30. The transmission line 30, as illustrated in Fig. 1 B, comprises the signal line 4, the first conductive portion 6 and the second conductive portion 8.

The signal line 4 is positioned between the first conductive portion 6 and the second conductive portion 8, and is electrically isolated from the first conductive portion 6 and the second conductive portion 8. The signal line 4 is aligned with the channel 20.

As illustrated in Fig. 1A, the module 40 comprises a dielectric substrate 42 that separates the first conductive portion 6 and the signal line 4. In the manufactured transmission line 30, as illustrated in Fig. 1B, the signal line 4 depends from the dielectric substrate 42 and is closer to the channel 20 than the first conductive portion 6. In this example, the signal line 4 and the first conductive portion 6 occupy parallel planes that, in the completed transmission line 30, are parallel to the second conductive portion 8 at a base 24 of the channel 20.

It will be appreciated that the module 40, in this example, is configured as a microstrip module. The module 40 is a circuit module and may, for example, be a flexible printed circuit comprising a flexible dielectric substrate 42. In other examples, the module 40 may alternatively be part flexi & part solid, or just solid printed circuit board (PCB).

A co-ordinate system is defined for Figs. IA and I B using the vectors x, y and z. As is conventional, the vector cross-product of x and y equals z. The vector x is used to define a width, the vector y is used to define a height and the vector z is used to define a length.

It will be appreciated that the module 40 has a width that is greater than its height. It also has a length (not illustrated in the figure) that is greater than its width.

The support 10 has an upper surface 12 and the channel 20 is formed in the upper surface 12. The channel 20 has a width, a height (depth) and a length. In this example, but not necessarily all examples, the channel 20 has a rectangular cross-section. The channel 20 comprises side walls 22 which run parallel to the y direction and a base 24 that runs parallel to the x direction. However, it should be appreciated that other configurations of channels 20 with different cross-sections may be used. For example, in other examples the channel 20 (and transmission line 30) may have different widths and/or heights along its length. This might be useful to provide impedance transformations for example.

A volume 21 is formed within the channel 20. This volume 21 may, in some examples, be filled with an applied dielectric material that is similar or different to the material of the dielectric substrate 42. However, in other examples, the volume 21 may be a gap or void comprising gas such as, for example, air.

The second conductive portion 8, in this example, extends at least over the base 24 of the channel 20. In this example, but not necessarily all examples, the second conductive portion 8 not only extends over the base 24 of the channel 20 but it also extends over the side walls 22 of the channel 20 and onto the upper surface 12 of thesupportlO.

The channel 20 has a width, a length and a height. The width is greater than its height and its length (not shown) is greater than its width. The width of the channel is less than a width of the module 40 but greater than a width of the signal line 4.

The height of the channel 20 is greater than the height of the signal line 4, in this

example.

It will be appreciated that in the example illustrated in Fig. 1 B, that a combination of the module 40 and the support 10 forms a transmission line 30. In this example, the transmission line 30 is a stripline.

During operation of the transmission line 30, the first conductive portion 6 and the second conductive portion 8 are both connected to electrical ground to provide electromagnetic shielding to the signal line 4.

In the formed transmission line 30, the channel 20 and the module 40 both extend in parallel in the z direction. The dielectric substrate 42 of the module 40 completely encloses the channel 20 to form an enclosed elongate cavity that houses the signal line 4. The enclosed cavity comprises gas, such as air.

In some examples, but not necessarily all examples, the support lOis formed from a metal or metal alloy and the channel 20 is a channel formed in the metal which provides the second conductive portion 8. In other embodiments, the support 10 comprises a chassis with a metal coating, where the metal coating provides the second conductive portion 8.

The module 40 and the support 10 are interconnected, for example, using a conductive adhesive or conductive film 50. This interconnection may galvanically interconnect the first conductive portion 6 and the second conductive portion 8.

In the example of Fig. 2, the galvanic interconnection is achieved using rows of vias 54 which extend between the first conductive portion 6 and the second conductive portion 8 through the non-conductive dielectric layer 42, where the first and second conductive portions 6, 7 extend over the upper surface 12 of the support 10. The vias extend in the y direction and are filled with conductive material. The rows of vias 54 extend in the z direction, in parallel along the length of the module 40, and may have dielectric between each adjacent via 54.

Fig. 3 illustrates an example of a different apparatus 2 comprising a transmission line 30. The apparatus 2 illustrated is similar to the apparatus 2 illustrated in Fig. lB.

However, in this example, the signal line 4 does not depend from a lower surface of the dielectric 42. In this example, the signal line 4 is located within the dielectric 42.

Fig. 4 illustrates an alternative example of the apparatus 2. The apparatus 2 illustrated in Fig. 4 is the same as the apparatus 2 illustrated in Figs. 1B, 2 or 3 except that the channel 20 which is used to house the signal line 4 is positioned within an additional, wider channel 70 in the support 10. In this example, the channels 20, 70 are symmetrically stacked, with the channel 20 forming a central channel in the base of the additional, wider channel 70. The module 40 is positioned within the additional, wider channel 70 such that an upper surface 41 of the transmission line 30 is flush with an upper surface 12 of the support 10. The first conductive portion 6 is positioned within the additional, wider channel 70 such that it is flush with the upper surface 12 of the support 10.

The additional, wider channel 70 has a cross-section similar to the cross-section of the module 40. In this example, the cross-section is rectangular and the additional, wider channel 70 has parallel walls 72 extending in the y direction and a base 74 extending in the x direction. The second conductive portion S may extend over a portion of the base 74. In some examples, it may additionally extend over the side walls 72.

In each example of an apparatus 2 illustrated in Fig 1B, 2, 3 or 4, a signal line 4 is aligned with the channel 20. Alignment in this sense means that all the lateral edges of the signal line 4 (in the x direction) are within a projection in the y direction of the lateral edges of the channel 20 (in the x direction).

Although the signal line 4 is centrally positioned in the Figs, this may not be necessary.

Although a single signal line 4 is illustrated in the Figs, it should be appreciated that one signal line 4 may be replaced by signal lines 4. The multiple signal lines 4 may be co-planar, parallel signal lines 4 that are laterally separated but each of which is aligned with the channel 20, for example, as illustrated in Fig 9. Consequentially reference to a signal line or the signal line in the claims should not be interpreted as a single signal line unless it is referred to as a single signal line' or the single signal line' but should instead be interpreted as one or more signal lines.

Where two parallel signal lines 4 are used, as illustrated in Fig 9 for example, the two signal lines may be used for differential line signalling or multiple line signalling. In differential line signalling, the two signal lines 4 couple with each other electrically. In multiple line signalling, the two signal lines 4 carry independent signals which may, for example, be to/from different antennas.

A signal line 4 is defined in Fig 1B, 2, 3, 4, in a positive sense, as a presence of a conductor or high permittivity dielectric. This is illustrated explicitly in Fig iDA, where the microstrip module 40 has a signal line 4 formed from and coincident with a conductor 3. It will be appreciated by those skilled in the art that, in accordance with the extension of Babinet's Principle by Booker, an operationally equivalent signal line 4 may alternatively be defined in a negative (complementary) sense, as illustrated in Fig lOB, as an absence 5 within a layer 7 of conductor or high permittivity dielectric.

The use of the term signal line' should be considered to be an inclusive definition that encompasses both a signal line 4 defined positively (Fig 1OA) and a signal line defined negatively (Fig lOB).

The use of the term positive signal line' should be considered to be an exclusive definition that encompasses a signal line 4 defined positively (Fig 1OA) and excludes a signal line defined negatively.

The use of the term negative signal line' should be considered to be an exclusive definition that encompasses a signal line 4 defined negatively (Fig lOB) and excludes a signal line defined positively.

The use of terms such as microstrip' or stripline' are intended to cover the use of a positive signal line 4 and also the use of a negative signal line 4.

As illustrated in Figs. 7A, 7B and 7C, the support 10 may be a component 102 of an electronic device 100. The component 102 may, for example, be an internal component of the electronic device 100 or an external component of the electronic device 100.

In this example, but not necessarily all examples, the component 102 has a first surface 104 and a second surface 106. The channel 20 may be formed in the second surface 106 of the support 10. Thus a transmission line 30 may be formed within the component 102 and/or at the second surface 106 of the component 102 in a manner that gives it a low-profile as illustrated in Fig. 8.

In the illustrated example, the component 102 is an exterior housing or cover of the electronic device 100. The first surface 104 is an exterior surface of the electronic device 100 and the second surface 106 is an interior surface of the electronic device.

The transmission line 30 may therefore be formed within the housing 102 and/or at the interior surface 106 of the housing 102 in a manner that gives a low-profile as illustrated in Fig 8.

In other examples, the component 102 may be a structural component interior to the electronic device 100, for example, a mechanical support frame, a display frame, etc. Figs. 5 and 6 illustrate examples of an electronic device 100 that comprises, at least, signalling circuitry 82, interface circuitry 84 and one or more transmission lines 30.

The transmission line 30 is used to transfer electromagnetic signals 80. In this example, the transmission line 30 is used for bidirectional communication. In other examples, the transmission line 30 may be used for unidirectional communication at radio frequencies, for example in a receive only mode or a transmit only mode.

The electronic device 100 may be a fixed electronic device or a portable electronic device. An example of a portable electronic device 200 is a hand-portable electronic device which is an electronic device that is sized to be carried in the palm of a user and fit within a jacket pocket.

Examples of portable electronic devices 100 include, but are not limited to, mobile cellular telephone, a personal digital assistant, a laptop computer, a tablet computer, a personal media player etc. Examples of fixed electronic devices 100 include permanently fixed devices and physically interconnected devices that are not normally meant to be continually moved, like televisions, displays, computer monitors, desktop computers, base stations or network equipment, wireless routers and modems, etc. It should be appreciated that an electronic device 100 may comprise additional circuitry (not illustrated) such as, for example, one or more processors, one or more memories, an output interface comprising, for example a display and/or an audio output, an input interface comprising, for example, a touch panel or buttons.

Referring to Fig. 5, the signalling circuitry 82 is configured to generate or receive a signal 80 and interface circuitry 84 is configured to externally communicate the signal from an electronic device comprising the transmission line 30. The transmission line 30 interconnects the signalling circuitry 82 and the interface circuitry 84.

In some examples, as illustrated in Fig. 6, the interface circuitry 84 may be a radio frequency antenna 90 and the signalling circuitry 82 may be radio frequency circuitry 92. The radio frequency circuitry 92 may be a transmitter, a receiver or a transceiver. In other examples, the interface circuitry 84 may be, for example, a universal serial bus (USB) interface.

In some but not necessarily all examples there may be antenna matching circuitry.

As used in this application, the term circuitry' refers to all of the following: (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and (b) to combinations of circuits and software (and/or firmware), such as (as applicable): (i) to a combination of processor(s) or (ii) to portions of processor(s)/software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (c) to circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present.

This definition of circuitry' applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term "circuitry" would also cover an implementation of merely a processor (or multiple processors) or portion of a processor and its (or their) accompanying software and/or firmware.

The term "circuitry" would also cover, for example and if applicable to the particular claim element, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in a server, a cellular network device, or other network device.

The radio frequency circuitry and the antenna may be configured to operate in a plurality of operational resonant frequency bands. For example, the operational frequency bands may include (but are not limited to) Long Term Evolution (LTE) (US) (734 to 746 MHz and 869 to 894 MHz), Long Term Evolution (LTE) (rest of the world) (791 to 821 MHz and 925 to 960 MHz), amplitude modulation (AM) radio (0.535-1.705 MHz); frequency modulation (FM) radio (76-108 MHz); Bluetooth (2400-2483.5 MHz); wireless local area network (WLAN) (2400-2483.5 MHz); hiper local area network (HiperLAN) (51 50-5850 MHz); global positioning system (GPS) (1570.42-1 580.42 MHz); US -Global system for mobile communications (US-GSM) 850 (824-894 MHz) and 1900 (1850 -1990 MHz); European global system for mobile communications (EGSM) 900 (880-960 MHz) and 1800 (1710-1880 MHz); European wideband code division multiple access (EU-WCDMA) 900 (880-960 MHz); personal communications network (PCN/DCS) 1800 (1710-1880 MHz); US wideband code division multiple access (US-WCDMA) 1700 (transmit: 1710 to 1755 MHz, receive: 2110 to 2155 MHz) and 1900 (1850-1990 MHz); wideband code division multiple access (WCDMA) 2100 (transmit: 1920-1 980 MHz, receive: 2110- 2180 MHz); personal communications service (PCS) 1900 (1850-1990 MHz); time division synchronous code division multiple access (TD-SCDMA) (1900 MHzto 1920 MHz, 2010 MHz to 2025 MHz), ultra wideband (UWB) Lower (3100-4900 MHz); UWB Upper (6000-1 0600 MHz); digital video broadcasting -handheld (DVB-H) (470- 702 MHz); DVB-H US (1670-1675 MHz); digital radio mondiale (DRM) (0.15-30 MHz); worldwide interoperability for microwave access (WiMax) (2300-2400 MHz, 2305-2360 MHz, 2496-2690 MHz, 3300-3400 MHz, 3400-3800 MHz, 5250-5875 MHz); digital audio broadcasting (DAB) (174.928-239.2 MHz, 1452.96-1490.62 MHz); radio frequency identification low frequency (RFID [F) (0.125-0.134 MHz); radio frequency identification high frequency (RFID HF) (13.56-13.56 MHz); radio frequency identification ultra high frequency (REID UHF) (433 MHz, 865-956 MHz, 2450 MHz).

A frequency band over which an antenna can efficiently operate is a frequency range where the antenna's return loss is less than an operational threshold. For example, efficient operation may occur when the antenna's return loss is better than (that is, less than) -4dB or -6dB.

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.

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 brief 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 sub-class 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, although the channel 20 is illustrated in Fig. 7B as a rectilinear channel, in other examples, it may deviate from rectilinear, for example it might curve, bend or corner.

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.

I/we claim:

Claims

CLAIMS1. An apparatus comprising: a support comprising a channel; and a transmission line comprising a signal line, a first conductive portion, and a second conductive portion, wherein the signal line is positioned between the first conductive portion and the second conductive portion and is electrically isolated from the first conductive portion and the second conductive portion; wherein the signal line is aligned with the channel.
2. An apparatus as claimed in claim 1, wherein the first conductive portion and the signal line are separated by a dielectric, wherein the signal line, first conductive portion and the dielectric in combination form a microstrip module.
3. An apparatus as claimed in claim 1, wherein the first conductive portion and the signal line are separated by a dielectric, wherein the signal line, first conductive portion and the dielectric in combination form a circuit module.
4. An apparatus as claimed in claim 1, wherein the first conductive portion and the signal line are separated by a dielectric, wherein the signal line, first conductive portion and the dielectric in combination form a flexible printed circuit.
5. An apparatus as claimed in any of claims 2 to 4, wherein the second conductive portion is positioned within the channel.
6. An apparatus as claimed in any preceding claim wherein the first conductive portion, the signal line and the second conductive portion form, in combination, a stripline.
7. An apparatus as claimed in claim 6, wherein the first conductive portion and the second conductive portion are galvanically interconnected.
8. An apparatus as claimed in claim 7, wherein the first and second conductive portions are galvanically interconnected through vias in a dielectric.
9. An apparatus as claimed in any preceding claim, wherein the first conductive portion and the second conductive portion are galvanically interconnected to electrical ground.
10. An apparatus as claimed in any preceding claim, wherein the channel is an elongate channel comprising a base and opposing side walls, wherein at least the base is conductive and provides at least a portion of the second conductive portion.
11. An apparatus as claimed in claim 10, wherein the side walls are electrically conductive and provide at least a portion of the second conductive portion.
12. An apparatus as claimed in any preceding claim, wherein the support is metal and the channel is formed in the metal.
13. An apparatus as claimed in any one of claims 1 to 11, wherein the support comprises a metal coating that provides the second conductive portion.
14. An apparatus as claimed in any preceding claim, wherein the channel is completely enclosed by a dielectric layer supporting the signal line.
15. An apparatus as claimed in claim 14, wherein the enclosed channel comprises gas.
16. An apparatus as claimed in any preceding claim, wherein the channel is positioned within an additional, wider channel in the support.
17. An apparatus as claimed in claim 16, wherein the first conductive portion is positioned within the additional, wider channel.
18. An apparatus as claimed in any preceding claim, wherein an upper surface of the transmission line is flush with an upper surface of the support.
19. An apparatus as claimed in any preceding claim, wherein the channel is formed in an interior surface of the support.
20. An apparatus as claimed in claim 19, wherein the support is an exterior housing or cover of an electronic device.
21. An apparatus as claimed in any preceding claim, wherein the signal line is configured to provide at least one of unidirectional and bidirectional communication at high frequencies.
22. An apparatus as claimed in any preceding claim comprising signalling circuitry configured to generate or receive a signal and interface circuitry, wherein the transmission line interconnects the signalling circuitry and the interface circuitry.
23. An apparatus as claimed in claim 22, wherein the interface circuitry is configured to communicate externally from an electronic device comprising the apparatus.
24. An apparatus as claimed in any preceding claim comprising a transmission line comprising multiple signal lines, the first conductive portion, and the second conductive portion, wherein the signal lines are positioned between the first conductive portion and the second conductive portion and are electrically isolated from the first conductive portion and the second conductive portion; wherein the signal lines are aligned with the channel.
25. An apparatus as claimed in claim 24, wherein the multiple signal lines are configured for differential line signalling.
26. A portable electronic device comprising apparatus as claimed in any of the preceding claims.
27. A method comprising: interconnecting a module and a support to form a transmission line, wherein the module comprises a signal line and a first conductive portion, and wherein the support comprises a channel and a second conductive portion, and wherein the transmission line comprises the signal line, the first conductive portion and the second conductive portion, wherein the signal line is positioned between the first conductive portion and the second conductive portion and is electrically isolated from the first conductive portion and the second conductive portion, and wherein the signal line is aligned with the channel.
28. A system comprising means for performing the method of claim 27.