Invented by Giovanni Vannucci, Paul Shala Henry, Thomas M. Willis, III, AT&T Intellectual Property I LP
The AT&T Intellectual Property I LP invention works as followsAccording to one or more embodiments a MIMO Transceiver generates and transmits first electromagnetic waves in accordance with MIMO techniques. The MIMO transceiver generates first electromagnetic wave on a plurality transmission lines in response to the first signals. These first electromagnetic waves are guided along the plurality transmission lines by a plurality surfaces.
Background for Multi-input Multi-output Guided Wave System and Methods for Use Therewith
Smart phones and other mobile devices are becoming more ubiquitous and data usage is increasing, so macrocell base stations devices and the existing wireless infrastructure will need to have higher bandwidth capabilities in order to meet increased demand.” Small cell deployment is being explored to provide more mobile bandwidth. Picocells and microcells offer coverage in smaller areas than traditional macrocells.
In addition, most households and businesses have come to rely upon broadband data access for services like voice, video, and Internet browsing. Broadband access networks can be used for satellite, 4G, 5G wireless, powerline communication, fiber, cable and telephone networks.
One or more embodiments will now be described using reference to the drawings. Like reference numerals refer to like elements throughout all of the drawings. The following description will provide an explanation of each embodiment. However, it is clear that many embodiments can be used without these details and without applying to any particular standard or networked environment.
In one embodiment, a guided-wave communication system is shown for sending and receiving communication signals like data or any other signaling via guided electromagnetic wave. Guided electromagnetic waves can include surface waves and other electromagnetic waves, which are bound to or guided through a transmission medium, as described in this invention. You will see that guided wave communications can be used with a wide variety of transmission media without departing from the examples. You can use one or more of these transmission media, alone or in combination with others: wires, insulated or uninsulated, single-stranded, multi-stranded, wire bundles of Category 5e or other twisted pair cables, wires, wire bundles, cables; conductors of different shapes or configurations such as unshielded, twisted pair cables, single twisted pairs, Category 5,e or other twisted couple cable bundles; non-conductors, such as dielectric pipes or rods, rails or other dielectric material; or any combination of conductors or dielectric materials or other types; or other guided-wave transmission media.
Inducing guided electromagnetic waves along a transmission medium is possible without regard to any charge, current, or electrical potential that is injected into the medium or transmitted through it as part of an electric circuit. In the example of a wire transmission medium, it should be noted that although a small current may form in response to propagation of electromagnetic waves along the wire’s surface, this is due to the propagation and not to any electrical potential, charge, or current that is injected in to the wire. To propagate along the wire’s surface, the electromagnetic waves that travel along it do not require an electric circuit (e.g., ground or other electrical return path). Therefore, the wire is a single transmission line and is not part an electrical circuit. An example of electromagnetic waves that can travel along an open circuit wire is the one where it’s configured as an electric open circuit. In some embodiments, a wire may not be necessary. The electromagnetic waves can propagate along single-line transmission mediums that are not conductorless.
More generally, ‘guided electromagnetic waves?” Or?guided electromagnetic waves? The subject disclosure describes how the transmission medium is affected by the presence a physical object. This could be a bare wire or any conductor, a dielectric with a dielectric core and/or without an inner shield, a dielectric wire, an insulated or insulator wire bundle or another solid, liquid, or non-gaseous medium, which is at least partially bound or guided by the object, and that propagates along the path of that object. This physical object may be used as at least one part of a transmission media that guides through one or more interfaces of transmission medium (e.g. an outer, inner, or an interior portion between the outer, inner, surfaces, or any other boundary between elements in the transmission medium). A transmission medium can support multiple transmission paths across different surfaces. A stranded wire bundle or cable may be capable of supporting electromagnetic waves. These electromagnetic waves can be guided by the outer surface or bundle of the wire or stranded cables, or by inner cable surfaces that connect two, three, or more wires in the wire bundle or stranded wire. Interstitial areas, such as stranded cables, insulated twisted-pair wires or wire bundles, can allow electromagnetic waves to be guided. The subject disclosure describes how guided electromagnetic waves are launched from a transmitting device and propagate along a transmission medium to be received by at least one receiver device. The transmission of guided electromagnetic waves can carry data, energy and/or other signals from one device to another.
Conductor” as used in this article. Based on the definition of the term “conductor” From IEEE 100, The Authoritative Dictionary of IEEE Standards Terms 7th Edition 2000, it means any substance or body that allows electricity to flow continuously along it. The terms ‘insulator’,?conductorless? are interchangeable. ,?conductorless? Based on the definition of the term “insulator” An insulator is a device or material that prevents electrons or ions from moving easily. This definition comes from IEEE 100, The Authoritative Dictionary of IEEE Standards Terms (7th Edition, 2000). An insulator or conductorless or nonconductive materials can be mixed intentionally (e.g. doped) or unintentionally to create a substance that has a small amount a conductor. The resulting substance might be resistant to continuous electric currents. A conductorless member, such as a dielectric core or dielectric rod, does not have an inner conductor or a shield. The term “eddy current” is used in this document. Based on the definition of the term “conductor” Based on a definition of the term “conductor” in IEEE 100, The Authoritative Dictionary of IEEE Standards Terms (7th Edition, 2000), a current that circulates within a metallic material due to electromotive forces induced from a variation of magnet flux. It is possible for an insulator or conductorless material in the above embodiments to permit eddy currents to circulate within the doped conductor or intermixed conductor. However, such a continuous flow, if any, of an electric current along an insulator or conductorless material is much smaller than the flow of an electricity along a conductor. In the present disclosure, an insulator and a conductorless/nonconductor material are not considered conductors. What is the definition of “dielectric?” An insulator that is able to be polarized using an applied electric field. A dielectric placed in an electrical field does not allow electric charges to flow continuously through it like they would in a conductor. Instead, the average equilibrium positions of electric charges shift slightly, causing dielectricpolarization. What are the terms “conductorless transmission medium” and “non-conductor transmit medium?”? A transmission medium that is made up of any material or combination of materials, but does not have a conductor between the sending device and the receiving device along the conductorless transmit medium or non-conductor transmit medium.
Guided electromagnetic waves are not restricted to free space propagation, such as unguided or unbounded wireless signals. Their intensity decreases in proportion to the distance traveled. However, guided electromagnetic wave propagation can occur along a transmission medium with a lower loss of magnitude per unit distance than unguided electromagnetic radiation.
Guided electromagnetic waves, unlike electrical signals, can propagate between a sending device and a receiver device without the need for an additional electrical return path. Guided electromagnetic waves can travel from a sending device through a conductorless transmission medium that does not contain any conductive components, such as a rod, dielectric strip, or pipe, or via a transmission media with only one conductor (e.g. a single wire or insulated wire in an open circuit electrical circuit). Even if a transmission media contains one or more conductors, guided electromagnetic wave propagation along the medium can generate currents that flow in the direction of the guided waves. This allows for guided electromagnetic waves to propagate from a sending device into a receiving device along the transmission medium without the need for opposing currents (e.g., a single conductor or insulated wire configured in an open electrical circuit).
In an example, electrical systems transmit and receive electric signals between sending devices and receiving devices using conductive media. This is a non-limiting illustration. These systems rely on an electric forward path and an electronic return path. Consider a coaxial cable with a center conductor, ground shield and an insulator. In an electrical system, a first terminal can be connected with the center conductor. A second terminal can be connected with the ground shield or another second conductor. The sending device can inject an electrical signal into the center conductor through the first terminal. This will cause forward currents to flow along the conductor and return currents to the ground shield or second conductor. For a two-terminal receiving device, the same conditions apply.
Consider, however, a guided wave communications system, such as the one described in this disclosure, that can use different types of transmission mediums (including a coaxial cable among others) to transmit and receive guided electromagnetic waves without an electrical return path. One embodiment of the subject disclosure allows for guided electromagnetic waves to propagate along the outer surface of a coaxial cables. The guided electromagnetic wave can create forward currents on ground shield but the guided waves don’t require return currents, such as on the center conductor, to allow the guided magnetic waves to propagate along coaxial cable’s outer surface. This is true for all other transmission media that are used in a guided wave communication network to transmit and receive guided electromagnetic waves. Guided electromagnetic waves can be induced by the guided-wave communication system on a wire, an insulated, or dielectric transmission medium. They can propagate along the wire, the insulated, or dielectric transmission medium, without the need for return currents.
Electrical systems that require forward or return conductors for carrying the corresponding forward or reverse currents on conductors to allow the propagation electrical signals injected from a sending device are different from guided wave systems, which induce guided electromagnetic waves at an interface of a transmission media without requiring an electric return path to enable propagation of the guided waves along that interface.
It should be noted that guided electromagnetic wave described in the subject disclosure may have an electromagnetic field structure that lies substantially or primarily on the outer surface a transmission medium, so that it can be bound to or guided via the outer material of the transmission media and propagate non-trivial lengths along or on the outer surface. Other embodiments of guided electromagnetic waves may have an electromagnetic field structure that is primarily or substantially below the outer surface of a transmission media. This allows it to be bound or guided by the inner material (e.g., dielectric materials) and to propagate nontrivial distances within this inner material. Other embodiments allow guided electromagnetic waves to have an electromagnetic field structure which lies in a region that is both partially below and partially above the outer surface of a transmission media. This allows them to be bound or guided by the region of the transmission material and to propagate non-trivial lengths within this area. The desired electromagnetic field structure in an embodiment may vary based upon a variety of factors, including the desired transmission distance, the characteristics of the transmission medium itself, and environmental conditions/characteristics outside of the transmission medium (e.g., presence of rain, fog, atmospheric conditions, etc.).
Various embodiments of the present invention relate to coupling device that can be referred as ‘waveguide couplings devices’, ‘waveguide couplers. Or, more simply, as “couplers” or “coupling devices?” or ?launchers? For launching or receiving/extracting guided electronic waves from and to a transmission medium. The wavelength can be smaller than the dimensions of the coupling devices and/or transmission mediums such as the circumference or cross section of a wire. These electromagnetic waves may operate at millimeter-wave frequencies (30 to 300 GHz) or at lower microwave frequencies, such as 300MHz to 30GHz. A coupling device can induce electromagnetic waves to propagate on a transmission medium, including: a stripe, arc, or other length dielectric material, a millimeter-wave integrated circuit (MIMIC), an antenna, horn, rod, slot, or another antenna, or an array of multiple antennas. The coupling device receives electromagnetic waves from a transmission medium or transmitter. The electromagnetic field structure can be carried under the outer surface or substantially on the surface of a coupling device. When the coupling is close to a transmission media, at least part of the electromagnetic wave couples or is bound to it, and then continues to propagate along the medium as guided electromagnetic waves. A coupling device is able to receive or extract a portion (or all) of guided electromagnetic waves and transmit them from the transmission medium. The coupling device can launch and/or receive guided electromagnetic waves from a device that sends them to a device that receives them. This is done without the need for an electrical return path. The transmission medium in this case acts as a waveguide for the propagation from the sending device towards the receiving device.
A surface wave, according to an example embodiment, is a type or type of guided wave that’s guided by a surface. This could be an exterior or outer surface, an interior or inner surface, or even an interstitial surface. For example, the area between wires in multistranded cables, insulated twisted pairs wires or wire bundles. In an example embodiment, the surface of the transmission medium which guides a surface waves can be a transitional surface between different media types. In the case of uninsulated or bare wires, the wire’s surface can be either the exterior or interior conductive surface of uninsulated wires that are exposed to air or space. Another example is that of an insulated wire. The wire’s surface can be the conductive section of the wire that touches the inner surface of its insulator portion. The transmission medium’s surface can be either the inner surface of an insulator or conductive surface. Any material area of a transmission medium could also be a surface. The transmission medium’s surface can include the inner portion of an insulation that is disposed on the wire that contacts the insulator. The properties of the surface that guides an electromagnetic waves can be affected by the relative properties of the conductor, air and/or insulator. They also depend on the frequency and mode of propagation.
In an example embodiment, the term “about” refers to the term. a wire or other transmission medium used in conjunction with a guided wave can include fundamental guided wave propagation modes such as a guided waves having a circular or substantially circular field pattern/distribution, a symmetrical electromagnetic field pattern/distribution (e.g., electric field or magnetic field) or other fundamental mode pattern at least partially around a wire or other transmission medium. Zenneck waves propagate along one planar surface of a planar transmission media. However, guided electromagnetic waves according to the subject disclosure can be bound to a transmission media with electromagnetic field patterns that surround or circumscribe the non-planar transmission medium with electromagnetic energies in all directions or in all but a finite amount of azimuthal null directions. These field strengths are close to zero for infinitesimally small azimuthal Widths.
These non-circular field distributions may be unilateral or multilateral, with one or two axial lobes that have a relatively high field strength and/or one/more null directions of zero field strength/substantially zero-field strengths, or null regions that are characterized as relatively low-field strength/zero-field strength. According to one example embodiment, the field distribution may also vary depending on azimuthal orientation around a transmission media. This means that one or more angular areas around the transmission medium can have an electric field strength or magnetic field strength (or combination thereof), that is greater than one or two other regions of azimuthal alignment. As the guided waves travel along the wire, it will be apparent that the relative positions or orientations of higher order modes can change, especially if they are asymmetrical.
In addition, a guided wave propagates?about? A guided wave can propagate along a wire or any other type of transmission medium. This includes the fundamental wave propagation modes (e.g. zero order modes), as well as non-fundamental modes like higher-order guided waves modes (e.g. 1st or 2nd order modes). Higher-order modes can include symmetrical modes with a circular or substantially circular electric field distribution and/or an symmetrical electric field distribution. Asymmetrical modes, and/or other guided waves (e.g. surface), may also have non-circular or asymmetrical field distributions around wires or other transmission media. The subject disclosure’s guided electromagnetic waves can travel along a transmission medium, from the sending device to a receiving device, or along a coupling apparatus via one or more of the following modes: a fundamental transverse magnet (TM) TM00 (or Goubau) mode or fundamental hybrid mode (EH/HE)?EH00? mode or?HE00 Mode, a transverse electromagnetic?TEMnm? Mode, a transverse electromagnetic?TEMnm?
Guided wave mode” is the term used herein. Refers to a guided propagation mode of a transmission media, coupling devices, or other system components of a guided-wave communication system that propagates for nontrivial distances along its length.
The term’millimeter-wave’ as used herein refers to electromagnetic waves/signals that fall within the?millimeter wave frequency band. Can refer to electromagnetic waves/signals falling within the?millimeter wave frequency band? between 30 GHz and 300 GHz. Microwave is a term that refers to electromagnetic waves/signals. Microwaves can be used to refer to electromagnetic signals/signals falling within a “microwave frequency band”. From 300 MHz up to 300 GHz. The term “radio frequency” is used. The term?radio frequency? oder?RF? can be used to refer to electromagnetic waves/signals that fall within the?radio frequency band. The term?RF? can be used to refer to electromagnetic signals/waves that fall within the ‘radio frequency band? between 10 kHz and 1 THz. Wireless signals, electrical signals and guided electromagnetic waves, as described in this disclosure, can operate at any frequency, including frequencies within the millimeter-wave or microwave frequency bands. When a transmission medium or coupling device includes a conductor element, the frequency at which guided electromagnetic waves are propagated along the transmission medium and/or carried by it can be lower than the mean collision frequency for the electrons within the conductive elements. The frequency of the guided electromagnetic wave that is carried by the coupling devices and/or propagate through the transmission medium may be non-optical, e.g. a radio frequency that falls below the range of optical frequencies which begins at 1 THz.
It is also appreciated that a transmission media described in the subject disclosure may be configured to be opaque, or at least substantially reduce, propagation of electromagnetic wave operating at optical frequencies (e.g. greater than 1 THz).Click here to view the patent on Google Patents.