Non-contact interface for MM wave near-field communication

Abstract

To provide a method to interface removable system modules without using physical / ohmic contacts.SOLUTION: In a system 100, a first waveguide 110 has a first NFC (near field communication) resonator 112 coupled to an end of the first waveguide 110. A second waveguide 111 has a second NFC resonator 113 coupled to the second waveguide 111. The first NFC resonator 112 is spaced apart from the second NFC resonator 113 by a distance of a certain gap 104. Transmission of a signal 203 propagated by the first waveguide 110 across the gap 104 to the second waveguide 111 is enhanced by a confined near field mode magnetic field 205 produced by the first NFC resonator 112 in response to a propagating wave that is coupled to the second NFC resonator 113.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure generally relates to Near Field Communication (NFC) as an alternative to physical / ohmic contacts for communication between system modules.

Background Art

[0002] In electromagnetic and communication engineering, the term waveguide can refer to any linear structure that conveys electromagnetic waves between endpoints. The original and most common means is a hollow metal pipe used to carry radio waves. This type of waveguide is used as a transmission medium for the purpose of connecting microwave transmitters and receivers to their antennas in devices such as microwave ovens, radar sets, satellite communications, and microwave wireless links.

[0003] Dielectric waveguides use a solid dielectric core instead of a hollow pipe. A dielectric is an electrical insulator that can be polarized by an applied electric field. When a dielectric is placed in an electric field, charges within the material do not flow like they do in a conductor but only shift slightly from their average equilibrium positions, thereby creating dielectric polarization. Due to dielectric polarization, positive charges are displaced towards the electric field and negative charges shift in the opposite direction. This creates an internal electric field that reduces the overall field within the dielectric itself. When the dielectric is composed of weakly bonded molecules, these molecules polarize and reorient so that their symmetry axes align with the electric field. The term "insulator" implies weak electrical conduction, while "dielectric" typically refers to highly polarizable materials, and polarization is represented by a number called the dielectric constant (εk) and / or a number called the relative permittivity (εr). The term "insulator" generally indicates electrical interference, while the term "dielectric" indicates the material's energy storage capacity due to polarization.

[0004] Electromagnetic waves in a metal pipe waveguide can be imagined to propagate along a zigzag path, repeatedly reflected between the walls on either side of the waveguide. In the specific case of a rectangular waveguide, a rigorous analysis can be based on this view. A similar view is used for propagation in dielectric waveguides, but the waves are confined within the dielectric by total internal reflection at the dielectric walls.

[0005] Near-field communication (NFC) is a wireless technology that enables two devices to communicate at close range, approximately 10 cm or less. Various protocols using NFC have been internationally standardized within NFC Forum specifications, defined, for example, in ISO / IEC 18092, ECMA-340, and ISO 14443. NFC allows mobile devices to interact with the subscriber's immediate environment. This proximity contactless technology allows mobile devices to be used as credit cards for accessing public transport, accessing secure locations, and many other applications. Contactless systems are commonly used as payment systems for access control IDs (e.g., employee badges) and public transport. Recently, credit cards have begun to incorporate NFC capabilities. [Overview of the project]

[0006] In the example illustrating the system, a first waveguide has a first resonator coupled to the end of the first waveguide. A second waveguide has a second resonator coupled to the second waveguide. The first resonator is spaced apart from the second resonator by a certain gap distance. The transmission of a signal propagated across the gap to the second waveguide by the first waveguide is amplified by a confinement near-field mode magnetic field generated by the first resonator in response to the propagating wave coupled to the second resonator. [Brief explanation of the drawing]

[0007] [Figure 1] This is a side view of a system illustrating near-field coupling across the gap between two waveguides using a resonator. [Figure 2]This is a side view of a system illustrating near-field coupling across the gap between two waveguides using a resonator.

[0008] [Figure 3A] An example coupler and resonator placed in the waveguide of Figure 1 or Figure 2 are shown in more detail. [Figure 3B] An example coupler and resonator placed in the waveguide of Figure 1 or Figure 2 are shown in more detail. [Figure 3C] An example coupler and resonator placed in the waveguide of Figure 1 or Figure 2 are shown in more detail. [Figure 4] An example coupler and resonator placed in the waveguide of Figure 1 or Figure 2 are shown in more detail.

[0009] [Figure 5] This is a graph illustrating the simulated operation of the system shown in Figure 1 or Figure 2. [Figure 6] This is a graph illustrating the simulated operation of the system shown in Figure 1 or Figure 2. [Figure 7] This is a graph illustrating the simulated operation of the system shown in Figure 1 or Figure 2.

[0010] [Figure 8] This is a block diagram of an exemplary system using a waveguide with a resonator for NFC communication between modules.

[0011] [Figure 9] Figure 8 provides a more detailed example of the modules for the system shown.

[0012] [Figure 10] Figure 8 is a diagram illustrating the example system.

[0013] [Figure 11] This is a flowchart illustrating the operation of near-field communication (NFC) between neighboring modules.

[0014] [Figure 12] FIG. 2 is a cross-sectional view of another embodiment of a system using near-field coupling across a gap.

[0015] [Figure 13] FIG. 8 illustrates another embodiment of a system using a resonator to improve the coupling efficiency of NFC across a gap between waveguides. [Figure 14] FIG. 11 illustrates another embodiment of a system using a resonator to improve the coupling efficiency of NFC across a gap between waveguides. [Figure 15] FIG. 14 illustrates another embodiment of a system using a resonator to improve the coupling efficiency of NFC across a gap between waveguides. DETAILED DESCRIPTION

[0016] In the drawings, for the sake of consistency, like elements are denoted by like reference numerals.

[0017] As the frequency in electronic components and systems increases, the wavelength correspondingly decreases. For example, many computer processors now operate in the gigahertz range. As the operating frequency increases up to the sub-terahertz range, the wavelength becomes short enough that a signal line longer than a certain short distance can act as an antenna and signal radiation can occur. For example, in a low dielectric constant material with a dielectric constant of 3, such as a printed circuit board, a 100 GHz signal can have a wavelength of about 1.7 mm. Therefore, a signal line only 1.7 mm long can act as a full-wave antenna and radiate a significant portion of the signal energy in the signal line material.

[0018] Waves in free space propagate omnidirectionally as spherical waves. Thus, in a far-field situation, the wave loses its power in proportion to the square of the distance. That is, at a distance R from the wave source, the power is 1 / R of the power at the wave source.

[0016] In such random wave propagation, interference with other nearby systems may occur and may violate the emission limits set by standardization bodies such as the FCC and IEC.

[0019] Waveguides are useful for carrying high-frequency signals over relatively long distances. Waveguides confine waves to one-dimensional propagation, and therefore, under ideal conditions, waves do not lose power during propagation. Electromagnetic wave propagation along the axis of a waveguide is described by the wave equation. The wave equation is derived from Maxwell's equations, and the wavelength depends on the structure of the waveguide and the materials within it (air, plastic, vacuum, etc.), as well as the frequency of the wave. There are only a few categories of waveguides commonly used. The most common type of waveguide has a rectangular cross-section, which is usually not a square cross-section. The longer side of this cross-section is usually about twice the length of the shorter side. These waveguides are useful for carrying electromagnetic waves that are polarized horizontally or vertically.

[0020] For the extremely short wavelengths encountered in subterahertz radio frequency (RF) signals, dielectric waveguides perform well and are far cheaper to manufacture than hollow metal waveguides. Furthermore, metal waveguides have a frequency cutoff determined by the waveguide size; propagation (of the electromagnetic field) does not occur below the cutoff frequency. Dielectric waveguides have no fixed cutoff point and a wider operating range.

[0021] Using NFC coupled with waveguides to distribute signals between various modules can provide a low-cost interconnection solution. Embodiments may provide a method for interfaced detachable system modules without using physical / ohmic contacts.

[0022] Figures 1 and 2 are partial side views of an exemplary system 100 illustrating near-field communication (NFC) across a gap 104 between two waveguides 110 and 111 using resonators 112 and 113. In this example, the substrate 101 may include, or be coupled to, a high-frequency circuit element configured to generate a radio frequency (RF) signal. In some embodiments, the RF signal may have a fundamental frequency in an exemplary range of about 10 to 200 GHz. The substrate 101 may be a printed circuit board (PCB) realized using any commonly used or future-developed material used in electronic systems and packages, such as fiberglass, plastic, silicon, ceramic, or plex glass.

[0023] Waveguide 110 may be positioned close to the substrate 101 and may extend over a distance D1 from the substrate 101. As described above, waveguide 110 may be a metal waveguide, a dielectric waveguide, a dielectric-filled metal waveguide, or other known or future-developed transmission medium for RF signal propagation. Coupler 114 may be fabricated on the substrate 101 to emit RF signals into waveguide 110. For example, coupler 114 may be a short-circuit loop of microstrips connected to a circuit element that generates RF signals. In another embodiment, coupler 114 may be a differential loop in which microstrips on each side are fed differentially. In yet another embodiment, other known or future-developed structures may be used to emit RF signals into waveguide 110.

[0024] Similarly, another substrate 102 may include, or be coupled to, a high-frequency circuit element configured to receive an RF signal. In some embodiments, the RF signal may have a fundamental frequency in an exemplary range of about 10 to 200 GHz. The substrate 102 may be a PCB realized using any commonly used or future-developed material used in electronic systems and packages. This material may be fiberglass, plastic, silicon, ceramic, plex glass, etc.

[0025] Waveguide 111 may be positioned close to the substrate 102 and may extend from the substrate 102 over a distance D2. As described above, waveguide 111 may be a metal waveguide, a dielectric waveguide, a dielectric-filled metal waveguide, or other known or future-developed transmission medium for RF signal propagation. Coupler 115 may be fabricated on the substrate 102 to receive RF signals from waveguide 110. For example, coupler 115 may be a short-circuit loop of microstrips connected to a circuit element that receives RF signals. In another embodiment, coupler 115 may be a differential loop in which microstrips on each side are fed differentially. In yet another embodiment, other known or future-developed structures may be used to receive RF signals from waveguide 111.

[0026] The resonator 112 may be manufactured at the end of the waveguide 110 opposite to the coupler 114, as will be described later. Similarly, the resonator 113 may be manufactured at the end of the waveguide 111 opposite to the coupler 115. In this example, the end of the waveguide 110 containing the resonator 112 is spaced 104 apart from the end of the waveguide 111 containing the resonator 113. For example, this gap may simply be the space between the two ends and may be filled with air. In some embodiments, a solid material 103 may fill all or part of the gap 104. The solid material 103 may be a dielectric or insulating material, such as plastic, glass, fiberglass, ceramic, or plex glass.

[0027] Distances D1 and D2 can be relatively short in applications where the substrates are packaged within a system module located in close proximity. Such applications will be described later. In other applications, D1 and / or D2 can be longer if substrate 101 is located at a greater distance from substrate 102. For example, substrate 101 may be several inches or feet away from substrate 102, or even several hundred feet or more. Waveguides 110 and 111 enable low-loss signal confinement and propagation over long distances.

[0028] Figure 2 illustrates the operation of NFC in system 100. For example, the emission structure 114 can be a short-circuit or differential loop of microstrips that create a magnetic field 202 in waveguide 110 to match the TE01 mode H field of waveguide 110. This enables a transition from microstrip propagation mode to waveguide propagation mode. The H field 202 then induces a propagated E field 203 according to the waveguide propagation principle. When the propagated E field 203 interacts with the resonator 112, a current is generated that produces a confined near-field mode magnetic field 205. The confined near-field mode magnetic field 205 is essentially a non-radiated evanescent field that magnetically couples with the resonator 113 across the gap 104, generating an induced current in the resonator 113. The induced current in the resonator 113 then creates a magnetic field 206 that induces a propagated E field 207 in waveguide 111. When field E 207 reaches coupler 114, magnetic field 208 generates an RF signal, which can be routed to receiver circuit elements on substrate 102.

[0029] In this way, RF signals can be transmitted across the gap 104 from circuit elements on substrate 101 to circuit elements on substrate 102 via waveguides 110 and 111. In this process, losses or radiation to neighboring systems / components due to confined near-field mode magnetic fields generated by resonators at the ends of each waveguide in the vicinity of the gap are minimized.

[0030] Figures 3A-3C and 4 illustrate in more detail exemplary couplers and resonators placed in the waveguide of Figure 1 or Figure 2. Figure 3B is an end view looking into the waveguide 310 through the substrate 301. The description herein may apply to both waveguides 110 and 111 of Figure 1 or Figure 2. Figure 3A shows an exemplary IC 320 which may include RF circuit elements connected to the waveguide coupler 314. The IC 320 may include a receiver circuit element for processing RF signals received by the coupler 314 via the waveguide 310, or a transmitter circuit element for generating RF signals transmitted into the waveguide 310 by the coupler 314. For example, in some embodiments, the IC 320 may include both transmitter and receiver circuit elements.

[0031] Alternatively, for example, the coupler 314 may be a discrete loop soldered to the substrate 310. As shown in Figure 3B, the coupler 314 may be a differential loop having microstrips 321 on each side that differentially feed the coupler 314. In Figure 3A, the copper traces 321 are configured as microstrips on a ground surface 322. Figure 3C shows another implementation where one side of the loop 314 may be short-circuited to ground (323) for single-ended feed.

[0032] Referring to Figure 3B, the resonator 312 is essentially an open-loop structure configured to interact with the propagating waves in the waveguide on which the resonator 312 is mounted. For example, the resonator 312 may be manufactured on a single-layer substrate and mounted to the end of the waveguide 310 using known or future-developed techniques, such as using adhesive or by soldering mounting pads on the substrate to the metal waveguide. In some embodiments, the waveguide 310 may have a dielectric core. In this case, the resonator 312 may be formed on the end of the dielectric core using an additional process, such as inkjet printing with conductive ink. In another embodiment, the resonator 312 may be mounted on a dielectric such as dielectric 103 (refer again to Figure 1) near the end of the waveguide 310.

[0033] Figure 4 is an isometric view of couplers 112 and 113, illustrating how these couplers can be oriented toward each other and separated by the gap 104.

[0034] Figure 5 is a graph of electric field strength illustrating the simulated operation of the system in Figure 1 or Figure 2. In this example, the E-field 203 propagates through the waveguide 110 in the direction indicated by vector 502. When the E-field 203 strikes the resonator 112, it generates a strong confinement near-field mode magnetic field that magnetically couples to the resonator 113 across the gap 104 without significant loss or radiation to nearby systems / components. The confinement field acts as a non-radiating evanescent field.

[0035] Figure 6 is a graph illustrating the coupling efficiency as a function of the gap distance, where the gap distance is measured at the wavelength of the propagated signal. Line 602 in the graph illustrates the system without a resonator, and line 604 in the graph illustrates the operation of a system with resonators placed at the ends of the waveguides on both sides of the gap. With the use of a resonator, an efficiency improvement of approximately 1 dB can be observed for the example gap of 0.35 wavelengths. As mentioned above, at a frequency of 100 GHz, the wavelength is approximately 1.7 mm in a material with a dielectric constant of 3.

[0036] Figure 7 is a graph illustrating the coupling efficiency with respect to frequency. Line 702 in the graph illustrates the system without a resonator, and line 704 in the graph illustrates the operation of a system with resonators placed at the ends of the waveguide on both sides of the gap. In this example, the waveguide is configured to have propagation mode 1 starting at 100 GHz and propagation mode 2 starting at 200 GHz. In this case, the coupled resonators inserted into the gap are designed to have a limited bandwidth and can increase the coupling efficiency over a selected frequency band.

[0037] In another embodiment, several resonators tuned for different frequency ranges may be inserted to broaden the bandwidth. In yet another embodiment, a broadband resonator may be used to broaden the bandwidth.

[0038] Figure 8 is a block diagram of an exemplary system using a waveguide with a resonator for NFC communication between modules. System 800 is an exemplary programmable logic controller using inductive NFC communication between modules. A programmable logic controller (PLC) or programmable controller is a digital computer used for automating typical industrial electromechanical processes, such as controlling machinery in factory assembly lines, amusement rides, and light sockets. PLCs are used in many machines in many industries. PLCs are designed for multiple arrangements of digital and analog inputs and outputs, extended temperature ranges, resistance to electrical noise, and resistance to vibration and shock. Programs for controlling machine operation are typically stored in battery-backed or non-volatile memory. PLCs are an example of a “demanding” real-time system because they must produce output results in response to input conditions within a limited time; otherwise, unintended operation may occur. PLC systems are well known and will not be described in detail herein (see, for example, the Wikipedia article “Programmable Logic Controller” dated December 1, 2015, which is incorporated herein by reference).

[0039] In this example, some modules are referred to as "line cards." Various types of line cards can be installed on a chassis or rack and can be configured for various purposes. These purposes include controlling manufacturing processes, temperature control within buildings, and control of medical equipment. Therefore, electrical isolation is often required or desirable to prevent grounding loops or other interactions between various controlled devices. Various types of isolation devices, such as optical isolators and transformers, have been used to date.

[0040] This example includes a power line card 802, a data communication line card 810, and several processing line cards 820, 840, and 841. Figure 8 shows five line card modules, but the illustrative chassis may accommodate 10 or more modules. Although systems using line cards are illustrated herein, embodiments are not limited to line cards. Various types of modules may use the communication techniques described herein to provide reliable communication between removable modules.

[0041] In this example, the power line card 802 may generate one or more voltages that can be coupled to the power supply and distributed via the bus 804. The bus 804 may be coupled to each line card via a connector such as connector 805. Typically, the voltage bus 804 may be included in a backplane that provides support for connector 805.

[0042] For example, the data communication line card 810 may be configured to transmit and receive data to and from a remote host or another rack or chassis via a communication channel. Various types of communication line cards 810 may accommodate wireless or wired interfaces. Also, for example, internet connectivity to a local or wide area network may be provided by the line card 810. Alternatively, wireless connectivity to a WiFi network or cellular network may be provided by the line card 810.

[0043] For example, the processing line card 820 may include front-end interface logic 830, processing logic 831, and aggregator logic 832. The front-end interface logic 830 may be of various types to provide interconnection to the controlled equipment. For example, input and output signals, RS232 / 422 / 485 compatible signals, digital signals, analog signals, etc. Various types of logic may be provided, such as analog-to-digital converters (ADCs), digital-to-analog converters (DACs), relays, contacts, etc. The processing logic 831 may include programmable logic embedded in various types of hardware, such as microcontrollers, microprocessors, and memory. Line cards 840, 841, etc., may be identical or similar to line card 820 and may include various types and combinations of processing and interface logic as required for a given control task.

[0044] In this example, each line card is configured to communicate with the nearest line card on either side. For example, line card 810 may transmit to line card 820, which has a receiver 824, via transmitter 811. Similarly, line card 820 may transmit to the receiver 815 of line card 810 via transmitter 823. At the same time, line card 820 may transmit to a neighboring line card 840 via transmitter 822 and receive from the neighboring line card 840 via receiver 821.

[0045] Similarly, each line card in system 800 can communicate with other line cards in a daisy-chain configuration. Each line card includes an aggregator / de-aggregator logic function, such as 832 on online card 820. This function allows each line card to recognize the daisy-chain communication intended for that card. The aggregator / de-aggregator function also allows the line card to send communication packets. These communication packets are provided to the daisy-chain and then propagated through neighboring line cards to their final destination on the target line card. In this embodiment, the daisy-chain operates similarly to an Internet network protocol, with each aggregator 832 functioning as an Internet interface. In another embodiment, different types of known or future-developed peer-to-peer protocols may be used.

[0046] As described above, NFC can be used as a carrier medium for communication between neighboring line cards. Waveguide segments (such as waveguides 815, 825, and 816, 826) can be used to guide NFC between neighboring line card modules to minimize signal spreading and to interface with other systems and devices, as will be explained later.

[0047] Figure 9 is a more detailed diagram of the modules for the system of Figure 8. Figure 9 illustrates two exemplary line card modules 921 and 922, which are typical examples of various modules 810, 820, 840, etc., of system 800. Module 921 may include a substrate 901 on which various circuit components are mounted, such as an integrated circuit (IC) 951 containing transmitters and receivers, such as transmitter 832 and receiver 824 and / or transmitter 822 and receiver 821 of line card 820. In some embodiments, there may be a separate IC for each transmitter and receiver. For example, in another embodiment, one or more receivers and transmitters may be formed in a single IC. Similarly, module 922 may include a substrate 902 on which various circuit components are mounted, such as an integrated circuit (IC) 952 containing transmitters and receivers.

[0048] The integrated circuits 951 and 952 may also include aggregation logic, processing logic, and front-end logic. Alternatively, additional ICs including aggregation logic, processing logic, and front-end logic may be mounted on substrates 901 and 902. For example, substrate 901 may be a single-layer or multi-layer printed circuit board. IC 951 and other ICs may be mounted on substrate 901 using surface mount technology with through-holes, solder bumps, or bonding, or other known or future-developed packaging technology, depending on the operating frequency. Substrates 901 and 902 may be any commonly used or future-developed material used in electronic systems and packages, such as fiberglass, plastic, silicon, ceramic, or plex glass.

[0049] The substrates 901 and 902 may also include waveguide (WG) couplers 914, which are connected to the receiver and / or transmitter included in IC 951. WG couplers 915 may also be coupled to the receiver and / or transmitter included in IC 951 and 952. WG couplers 914 and 915 may be similar to coupler 314, referring again to Figures 3A and 3B. These couplers may be separate structures mounted on substrate 901 or embedded within substrate 901.

[0050] Waveguide 910 can be mounted approximately in the center on WG coupler 914. Similarly, waveguide 911 can be mounted approximately in the center on WG coupler 915. In this way, most of the electromagnetic energy emitted by WG coupler 914 is captured and confined by waveguide 910, thereby minimizing external radiation and signal loss of electromagnetic energy directed towards neighboring modules.

[0051] As described above, resonators may be attached to the ends of waveguides 910, 911 to convert the propagating waves in each waveguide into or from a confined near-field mode evanescent magnetic field around a resonator, thereby enabling NFC across the gap distance 904. Embodiments operate in near-field mode where isolation between neighboring modules is a fraction of the wavelength of the frequency transmitted by the IC951 transmitter. For example, a transmission frequency in the range of 100 GHz to 200 GHz may be used. However, in some embodiments, higher or lower frequencies may be used. A 100 GHz signal may have a wavelength of about 3 mm in air.

[0052] A shield 963 may be provided between the left WG coupler 915 and the right WG coupler 914 to minimize the "backscattering" of the field generated by each WG coupler. For example, the shield 963 may be a conductive layer connected to a ground reference for this module. The shield 963 is spaced at a distance greater than λ / 10 from each coupler 914, 915, where λ is the wavelength of the signal emitted by the coupler, to avoid capacitance effects that could narrow the bandwidth of the couplers. For example, the wavelength of a 30 GHz signal in a dielectric with εR of 1 is approximately 10.0 mm. In this example, the substrate 901 is a typical PWB material with εR of approximately 1.0. Therefore, as long as the shield is spaced at a distance of at least 1 mm (973) from each coupler, the capacitance effect should be minimized in a system operating at 30 GHz. Operation at lower frequencies may require larger spacing.

[0053] Near-field modes can generate an evanescent field that couples two neighboring resonators 912 and 913. Evanescent fields inherently exhibit exponential attenuation with increasing distance from the wave source. The close proximity of resonator 912 in module 921 to another resonator 913 in neighboring module 922, located only a few millimeters apart, allows for moderate TX-RX signal coupling using the near-field evanescent field, while mitigating the radiation limitations / concerns outlined in FCC Chapter 15.

[0054] The most similar example is a transformer. Strong self-coupling between coils reduces leakage to the outside. Furthermore, any leakage can be considered accidental. The requirements for accidental emission under the FCC are significantly more relaxed compared to those for intentional emission.

[0055] Module 921 may be enclosed in a housing generally shown as 961, 961. One side of the housing is shown as panel 961, and the other side of the housing is shown as panel 962 (e.g., metal or plastic). Typically, the thickness of the housing is several millimeters.

[0056] Furthermore, for example, waveguide 910 can be a dielectric block. Electromagnetic wave propagation through the dielectric block can be described by a wave equation. The wave equation is derived from Maxwell's equations, where the wavelength depends on the structure of the dielectric block, the material within it (air, plastic, vacuum, etc.), and the frequency of the wave. Waveguides 910 and 911 can confine the field emitted by the WG coupler 914 by having a dielectric constant and / or permeability significantly higher than that of the surrounding material and / or air, which can significantly reduce the wavelength of the electromagnetic field emitted by the WG coupler 914. Similarly, waveguides 910 and 911 can confine the field emitted by the WG coupler 914 by having a dielectric constant and / or permeability significantly lower than that of the surrounding material and / or air, which can significantly increase the wavelength of the electromagnetic field emitted by the WG coupler 914. Alternatively, waveguides 910 and 911 can be constructed from metamaterials that significantly reduce or increase the wavelength of the electromagnetic field emitted by the WG coupler 914.

[0057] For example, waveguides 910 and 911 may be dielectric blocks having a relative permittivity greater than approximately 2.0. Similarly, waveguides 910 and 911 may be dielectric blocks having a relative permittivity less than approximately 2.0.

[0058] In another embodiment, the dielectric waveguide 910 may have a conductive layer around its periphery to further confine and direct the electromagnetic field radiated by the WG coupler 914. This conductive layer may form sidewalls around the waveguides 910, 911 using metallic or non-metallic conductive materials such as metals like copper, silver, and gold, conductive polymers formed by ion doping, carbon and graphite-based compounds, and conductive oxides.

[0059] Depending on the material and thickness of the module wall 961, the waveguide 910 may be mounted simply in close proximity to the inner surface of the module wall 961 so that the radiated signal passes through the module wall 961. In some embodiments, a window may be provided in the module wall 961 so that the outer surface of the waveguide 910 may be flush with the outer surface of the module wall 961, slightly recessed from the outer surface of the module wall 961, or slightly protruding from the outer surface of the module wall 961. The approximate location on the surface of the housing where the waveguide is placed is referred to herein as a “port”.

[0060] Figure 9 shows a portion of a second module 922 that may be positioned adjacent to module 921. Module 922 may have a housing that includes a panel 962 which may be referred to as the "left" panel. Module 921 may have a panel 961 which may be referred to as the "right" panel. Module 922 may include a substrate 902 that holds a receiver and a transmitter, as well as various ICs such as IC 952 which may include WG couplers 914 and 915. Module 922 may also include a waveguide 911, which is positioned adjacent to the left panel 962 and aligned with WG 910 in module 921.

[0061] When modules 921 and 922 are installed in the chassis, the right panel 961 is adjacent to the left panel 962, as shown in 904. The waveguide 910 of module 921 and the waveguide 911 of module 922 are configured to be substantially aligned with each other. In this way, the signal generated by the transmitter in IC 951 can be supplied to the coupler 914, radiated into waveguide 910, thereby directed to the resonator 912, then received by the resonator 913 of module 922, emitted into waveguide 911, received by the coupler 914 on substrate 902, and thereby supplied to the receiver in IC 952.

[0062] Modules 921 and 922 can be easily removed from or inserted into the chassis without the contact wear previously required for signal communication between modules. Furthermore, the NFC using resonators 912 and 913 provides complete electrical isolation between module 921 and module 922. No additional isolation mechanism is required.

[0063] Figure 10 is an illustrative illustration of system 1000, which is another view of system 800 in Figure 8. The backplane 1006 provides a set of connectors 1005 for supplying power to each line card, as described with respect to connector 105 in Figure 1. As shown, each line card module is removable from the backplane 1006 by simply pulling the module out and disconnecting it from the connectors 1005. Typically, a rack or chassis is provided with the backplane 1006 to support the line cards when they are inserted into the connectors 1005.

[0064] Each line card module is enclosed in a housing which may be made of plastic or other suitable material. As described above, each line card may have a WG coupler, waveguide, and resonator arranged to form a contactless communication port on each side of the module. For example, module 1010 may have port 1055 on the right side of the module, and module 1020 may have port 1056 on the left side of the module which aligns with port 1055 when both modules are plugged into backplane 1006.

[0065] Similarly, module 1020 may have another port (not shown) on its right side, and module 1040 may have a port (not shown) on its left side that aligns when both modules are plugged into backplane 1006. As described above, all modules may have similar pairs of ports on both sides of each module so that daisy-chain communication is possible between all modules.

[0066] Figure 11 is a flowchart illustrating the operation of near-field communication between modules as described above. As also mentioned above, these modules can be part of a programmable logic control system used in industrial, commercial, and residential applications. A typical system may include a rack or chassis on which the set of modules is installed. Each module can communicate with nearby neighboring modules using near-field communication. In this near-field communication, an RF signal generated in one module can be EM-coupled to a receiver in a neighboring module using radiative coupling, near-field coupling, evanescent coupling, or any combination of these modes.

[0067] For example, a radio frequency (RF) signal may be generated in the first module (1102). In the examples shown in Figures 1 to 10, the RF signal may have a frequency in the range of 100 to 200 GHz. However, other systems may use higher or lower frequency RF signals by adjusting the physical size of the field-coupled and field-confinement components described herein.

[0068] An RF electromagnetic field may be generated in response to an RF signal from the first waveguide coupler of the first module (1104). For example, the RF electromagnetic field may be the result of moving waves formed in the microstrip loop, as described in relation to Figures 3A and 3B.

[0069] The resulting RF electromagnetic field is confined by the waveguide of the first module and directed towards a resonator at the end of the waveguide (1106). In response to the electromagnetic field propagating in the waveguide, a confined near-field mode magnetic evanescent field can be generated by the resonator.

[0070] The evanescent field can be inductively coupled to a similar resonator located at the end of the waveguide of a neighboring second module (1108). As described above, these two resonators are placed in close proximity when the modules are installed in the system, thereby minimizing the loss of generated energy into the surroundings. As described above, this coupling is made by EM coupling and can utilize the near-field of the electromagnetic field generated from the resonators. This coupling can also utilize the evanescent field formed by the first WG coupler. Some portion of the propagating field (from the waveguide of the first module) can be radiated across the gap between modules. Depending on the spacing between neighboring modules, one or both of these coupled modes or a combination thereof may occur. For example, this may simplify the process of complying with FCC emission requirements.

[0071] The resulting RF electromagnetic field propagates to the second WG coupler of the second module (1110).

[0072] The resulting RF signal can then be supplied to the RF receiver of the second module (1112). As described above, multiple modules in the system can communicate in a daisy-chain configuration so that any module can communicate with any other module in the system.

[0073] Known standard communication protocols (such as the Internet Protocol) can be used, and daisy-chained NFC physical media are treated as Ethernet. The Internet Protocol (IP) is the primary communication protocol in the set of Internet protocols for relaying datagrams across network boundaries. IP has the task of transporting packets from a source host to a destination host based solely on the IP address in the packet header. For this purpose, IP defines a packet structure that encapsulates the data to be transported. IP also defines an addressing method used to label datagrams with source and destination information. The first major version of IP, namely Internet Protocol version 4 (IPv4), is the dominant protocol on the Internet. Its successor protocol is Internet Protocol version 6 (IPv6).

[0074] Another embodiment may use another known or future-developed communication protocol for communication using daisy-chained NFC physical media as described herein.

[0075] In this way, embodiments can provide high-throughput communication between removable modules of a system using near-field communication techniques. The techniques described herein may be less expensive than alternative techniques such as optical couplers. NFC enables contactless communication between modules, thereby providing additional features in systems where isolation between modules may be required. Eliminate the need for isolation.

[0076] Figure 12 is a cross-sectional view of another embodiment of a system 1200 that uses near-field coupling across a gap 1204. In this example, the substrate 1201 has a waveguide 1210 formed within the substrate. The substrate 1201 may be a printed circuit board (PCB) mounted using any commonly used or future-developed material used in electronic systems and packages, such as fiberglass, plastic, silicon, ceramic, or plex glass. An integrated circuit 1220 may be mounted on the substrate 1201 and coupled to the waveguide 1210 using a coupler similar to the coupler 314 in Figure 3A. Another example of a waveguide formed on a substrate and coupled to an IC is described in U.S. Patent No. US9,306,263, title "Interface between an integrated circuit and a dielectric waveguide using a bipolar antenna and reflector," by Juan Herbsommer et al., which is incorporated herein by reference. [Patent Document 1] U.S. Patent No. US9,306,263

[0077] A second waveguide 1211 may be configured to interface with waveguide 1210. As described above, a resonator 1212 located at the end of waveguide 1211 and a neighboring resonator located at the end of waveguide 1210 may improve the coupling efficiency across the gap 1204. In this example, an isolation or dielectric layer 1202 may be formed over part or all of the substrate 1201. Layer 1202 may be formed from a variety of materials such as silicon dioxide, glass, quartz, ceramic, or plastic.

[0078] Figure 13 illustrates a portion of system 1300, which includes multiple resonators used for larger gaps. In this example, waveguides 1310 and 1311 are separated by a larger gap 1304. As mentioned above, resonators 1312 and 1313 may be placed at the ends of waveguides 1310 and 1311 to improve coupling efficiency across gap 1304. However, referring again to Figure 6, coupling efficiency decreases as the gap widens. Beyond nearly half a wavelength gap, the efficiency may be too low to obtain good results.

[0079] For example, by installing one or more resonators 1314 spaced apart across the gap, the effective length of the gap between each pair of resonators can be maintained at less than approximately 0.5 wavelengths.

[0080] Figure 14 illustrates a portion of system 1400 in which resonators are mounted on dielectrics near the ends of waveguides 1410, 1411. As described above, resonators 1412, 1413 can improve coupling efficiency across gap 1404. In this example, resonators 1412, 1423 can be applied to the surfaces of dielectrics 1461, 1462 that form all or part of the gap. For example, referring again to Figure 9, dielectric 1461 may represent the right panel 961 of the module, and dielectric 1462 may represent the left panel 962 of the module. In this way, waveguides 1410, 1411 can be simple waveguides positioned close to resonators 1312, 1413 when each module is assembled.

[0081] Figure 15 illustrates a portion of system 1500 in which waveguides 1510 and 1511 form a "T" crossing with a gap 1504 between them. In this example, resonators 1512 and 1513 may be installed in the waveguides to improve the coupling efficiency across the gap 1504. In other embodiments, other crossing configurations, such as 90-degree bend crossings and 45-degree bend crossings, may also be improved by resonators.

[0082] Various other embodiments are possible. For example, although a programmable logic controller system has been described herein, other types of modular systems may embody aspects of the exemplary embodiments to improve reliability.

[0083] While a module in which the inductive NFC port is located on the side of the module has been described herein, in another embodiment, the port may be located on the edge of the module, and the opposing port may be located on the backplane or on another surface near the edge of the module.

[0084] While a daisy-chained communication configuration has been described herein, other topologies may be formed in other embodiments. For example, a tree topology may be formed by providing ports on a backplane that correspond to the edge-mounted ports in each module.

[0085] While a simple dielectric block has been described herein, another embodiment may use metallic or nonmetallic conductive materials, such as ion-doped conductive polymers, carbon and graphite-based compounds, or conductive oxides, to form the sidewalls of the waveguide field confinement.

[0086] For example, dielectric or metamaterial waveguide field confinement devices can be manufactured on the surface of a substrate or module panel using an inkjet printing process or other 3D printing process.

[0087] Although dielectric waveguide field confinement devices with polymer dielectric cores have been described herein, other embodiments may use other materials such as ceramics or glass for the dielectric core.

[0088] Although waveguides having a rectangular cross-section have been described herein, other embodiments can also be readily implemented. For example, waveguides may have cross-sections that are square, trapezoidal, cylindrical, elliptical, or many other selected geometric shapes.

[0089] For example, the dielectric core of a conductive waveguide can be selected from a range of approximately 2.4 to 12. These values ​​are for commonly available polymer dielectric materials. Dielectric materials with higher or lower values ​​may be used when they become available.

[0090] Although subterahertz signals in the 100-200 GHz range have been described herein, waveguides and systems equipped with WG couplers and resonators for distributing higher or lower frequency signals can be implemented using the principles described herein by appropriately adjusting the physical size of the waveguides and resonators.

[0091] Components in a digital system may be referred to by different names and / or combined in ways not shown herein without deviating from the functionality described. In this description, the term “coupling” and its derivatives mean indirect, direct, optical, and / or wireless electrical connections. Therefore, when a first device is coupled to a second device, this connection may be via a direct electrical connection, an indirect electrical connection via other devices and connections, an optical electrical connection, and / or a wireless electrical connection.

[0092] In this specification, method steps may be presented and described sequentially, but one or more of the steps shown and described above may be omitted, repeated, performed simultaneously, and / or performed in an order different from the order illustrated and / or described herein. Therefore, the exemplary embodiments are not limited to any particular order of steps illustrated and / or described herein.

[0093] Modifications to the described embodiments are possible within the scope of the claims, and other embodiments are possible.

Claims

1. It is a system, The first module, A first substrate having a first surface and a second surface opposite to the first surface, The first integrated circuit on the first substrate, A first waveguide coupler on the first surface of the first substrate, which is coupled to the first integrated circuit, A second waveguide coupler on the second surface of the first substrate, which is coupled to the first integrated circuit, A first housing surrounding the first substrate, having a first side, a second side opposite the first side, a first port region on the first side, and a second port region on the second side, A first resonator adjacent to the first port region, A second resonator adjacent to the second port region, The first waveguide between the first resonator and the first waveguide coupler, The second waveguide between the second resonator and the second waveguide coupler, The first module, including A system that includes this.

2. The system according to claim 1, A system in which the first substrate includes a shield between the first waveguide coupler and the second waveguide coupler.

3. The system according to claim 1, The second module, A second substrate having a third surface and a fourth surface opposite to the third surface, The second integrated circuit on the second substrate, A third waveguide coupler on the third surface of the second substrate, which is coupled to the second integrated circuit, A second housing surrounding the second substrate, having a third side, a fourth side opposite the third side, and a third port region on the third side, A third resonator adjacent to the third port region, The third waveguide between the third resonator and the third waveguide coupler, The second module includes, The third module, A third substrate having a fifth surface and a sixth surface opposite to the fifth surface, The third integrated circuit on the substrate described above, The fourth waveguide coupler on the sixth surface of the third substrate, A third housing surrounding the third substrate, the third housing having a fifth side, a sixth side opposite the fifth side, and a fourth port region on the sixth side, A fourth resonator adjacent to the fourth port region, The fourth waveguide between the fourth resonator and the fourth waveguide coupler, The third module includes, It further includes, A system in which the third port area faces the second port area, and the fourth port area faces the first port area.

4. The system according to claim 3, A system further comprising a backplane including a first power connector coupled to the first module, a second power connector coupled to the second module, and a third power connector coupled to the third module.

5. The system according to claim 3, A system in which each of the first, second, and third modules is a line card.

6. The system according to claim 1, A system in which the first integrated circuit includes programmable logic circuit elements.

7. The system according to claim 1, A system in which the first resonator is a near-field communication (NFC) resonator.

8. The system according to claim 1, A system in which the first substrate is a printed circuit board (PCB).

9. The system according to claim 1, A system in which the waveguide coupler is located near the first end of the first waveguide, and the first resonator is located near the second end of the first waveguide opposite to the first end.

10. The system according to claim 1, The waveguide coupler is part of a system including a loop.

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