Launch of circularly polarized dielectric waveguides

Abstract

To provide a high frequency data system that uses dielectric waveguides to communicate electromagnetic waves carrying data signals.SOLUTION: A wave communication system includes an integrated circuit (102) and a multi-layer substrate (104). The multi-layer substrate (104) is electrically coupled to the integrated circuit (102). The multi-layer substrate (104) includes antenna structures (120TX1A, 120TX1B, 120TX2A, 120TX2B) configured to transmit circularly polarized waves in response to signals from the integrated circuit (102).SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] This application generally relates to high-frequency data systems, and more particularly to high-frequency data systems that use dielectric waveguides to communicate electromagnetic waves capable of carrying data signals.

Background Art

[0002] In many high-frequency data systems, two alternative media, namely copper wiring and optical cables, are used to communicate high-speed data. However, each of these approaches can have several drawbacks. For copper wiring, one drawback is the skin effect that occurs as the frequency increases. The skin effect is the tendency for alternating current signal current to be distributed only near the outer periphery (or skin) of the wiring, which increases the wiring impedance and causes significant signal loss at high frequencies. Optical cables are effective for long-distance spans as long as the signal is within the optical cable, but connections to intermediate or end devices cause losses and can have problems such as debris or vibration that can severely limit or disrupt optical cable communication efficiency in certain environments. Also, optical cables can be relatively expensive to implement and can also be expensive in terms of the power consumption of the associated communication circuit elements / systems.

[0003] Dielectric waveguides (DWGs) are high-frequency alternatives to copper wiring and optical cables. A waveguide is a structure that guides waves, including electromagnetic waves capable of carrying data. The following patents are incorporated herein by reference. (a) U.S. Patent No. 9,761,950, issued September 12, 2017, titled "Dielectric Waveguide with Embedded Antenna"; (b) U.S. Patent No. 9,705,174, issued July 11, 2017, titled "Dielectric Waveguide Having a Core and Cladding Formed on a Flexible Multilayer Substrate"; and (c) U.S. Patent No. 9,647,329, issued May 9, 2017, titled "Embedded Antenna with Embedded Dielectric for High Data Rate Communication Using Dielectric Waveguide".

Patent Document 1

[0004] The wave communication system includes an integrated circuit and a multilayer substrate. The multilayer substrate is electrically coupled to the integrated circuit. The multilayer substrate includes an antenna structure configured to transmit circularly polarized waves in response to signals from the integrated circuit. [Brief explanation of the drawing]

[0005] [Figure 1A] This is an exploded view of a dielectric waveguide system.

[0006] [Figure 1B] This is a plan view of a multilayer substrate and an integrated circuit (IC) die.

[0007] [Figure 1C] Figure 1B shows a partial cross-sectional view taken along line 1C-1C.

[0008] [Figure 2] This is a perspective view of a branch line coupler.

[0009] [Figure 3] This is a schematic diagram of the signal path from the IC die to the four transmitting antennas via two branching couplers.

[0010] [Figure 4] This is a perspective view of a circuit board component for a certain wave transmission / reception signal path.

[0011] [Figure 5] Figure 4, a perspective view, shows that a waveguide and isolation structure have been added.

[0012] [Figure 6] This is a plan view of an example of an alternative structure for a transmission or reception area, with modified shapes for the antenna, branch line coupler, and signal block structure. [Modes for carrying out the invention]

[0013] Figure 1A is an exploded view of a dielectric waveguide (DWG) communication system 100. The system 100 includes an integrated circuit (IC) die 102, a multilayer substrate 104, and transmit (TX) and receive (RX) DWG cable assemblies 106-1 and 106-2, respectively, which provide physical mounting and electrical coupling between these devices. The IC die 102 is physically mounted to a first side (e.g., the bottom) of the multilayer substrate 104 by a die-mounting technique or the like. Both the TX and RX cable assemblies 106-1 and 106-2 are physically mounted to the opposite side (e.g., the top) of the multilayer substrate 104 from the IC die 102 by mechanisms such as screws, clips, or mounts. The TX cable assembly 106-1 is axially aligned with the transmit region 108TX on the substrate 104, and the RX cable assembly 106-2 is axially aligned with the receive region 108RX on the substrate 104. Such matching and further mounting of the substrate 104 to the IC die 102 allows millimeter electromagnetic waves to communicate with such waves, which are communicated to and from the IC die 102, and between cable assemblies 106-1 and 106-2, by both antennas (and their respective feed structures) and waveguides constructed within the multilayer substrate 104.

[0014] The IC die 102 may have the attributes and dimensions of integrated circuit technology, such as being a 3mm x 3mm square. The IC die 102 includes a transceiver, generally shown as transceiver 102TXRX (connections not shown individually), configured to transmit and receive signals. The operating frequency and bandwidth of the transceiver signal may be selected according to the application, such as for communication along a DWG medium in the millimeter wave range (e.g., 110-140 GHz). Although not shown individually, the transceiver 102TXRX may include one or more processors (e.g., digital signal processors) that may support multiple transmit and receive channels, radio configurations, control, calibration, and programming of model changes to enable a wide variety of implementations. The IC die 102 includes a number of conductive components, such as die pads, generally shown in groups 110-G1 and 110-G2. The conductive areas 110-G1 and 110-G2 (e.g., die pads) are physically positioned to align with the conductive areas (e.g., lower pads) of the transmit and receive regions 108TX and 108RX, respectively, so that conductors (e.g., copper pillars or other bump structures) can electrically exist between opposing areas of such regions. Thus, when the IC die 102 is physically mounted to the multilayer substrate 104, it is also electrically coupled to the electrical path of the substrate 104, including the trace 104TR, for electrical connections between the IC die 102 and regions 108TX and 108RX. Through this electrical coupling, millimeter-wave signals can be communicated between the IC die 102 and an antenna constructed within the multilayer substrate 104, as will be described later.

[0015] Cable assemblies 106-1 and 106-2 each include dielectric cables 112-1 and 112-2, for example, a cylindrical outer cladding concentrically surrounding their respective cylindrical inner cores 113-1 and 113-2, although other cable configurations including dielectrics are also possible. The outer cladding has a dielectric constant ε(OC), and the inner core has a dielectric constant ε(IC). The diameter of the outer cladding may be in the range of 3 to 6 mm, and the diameter of the inner core may be in the range of 1.5 to 2 mm. Preferably, the inner core dielectric constant ε(IC) is sufficiently large compared to the outer cladding constant ε(OC) so that millimeter waves are coupled to the cable and their energy is concentrated in the inner core. In this way, even if the cable material is an intrinsic dielectric, which is often inherently insulating, the dielectric allows energy to move along it, while the insulator does not allow charge to pass through. Accordingly, the exemplary embodiment enables the use of relatively inexpensive dielectric materials for the cable core, such as polyethylene, and in relation to system 100, allows for efficient transmission of millimeter-wave signals from transceiver 102TXRX to cable 112-1, and thereby to a device (not shown) at the end of the cable. In this regard, each of the cable assemblies 106-1 and 106-2 also includes their respective metal waveguide couplers 114-1 and 114-2. In one exemplary embodiment, each waveguide coupler 114-x has a cylindrical shape with a height such as 1.5 mm and a central axis aligned with the central axis of core 113-x, and these axes are aligned with regions 108TX and 108RX, respectively. The outer diameter of cable 113-x may vary and may exceed the outer diameter of the corresponding waveguide coupler 114-x as shown in the illustrated example, while the outer diameter of core 113-x is smaller than the inner diameter of the corresponding waveguide coupler 114-x. With these dimensions and axial alignment, the inner diameter of each waveguide coupler 114-x is physically aligned with the respective transmit or receive regions 108TX and 108RX, and the cylindrical shape provides a circular cross-section for both physical and wave coupling to the transmit and receive regions 108TX and 108RX.Furthermore, in the exemplary embodiment, the wave communication within system 100 is circularly polarized, and therefore the metallic circular cross-section of each waveguide coupler 114-x helps guide the circular polarization between the dielectric cable internal core 113-x and the multilayer substrate 104.

[0016] Figure 1B is a plan view of the multilayer substrate 104, where the IC die 102 is shown as a dashed rectangle and is located beneath the substrate 104 in the figure. In this plan view, the transmitting region 108TX and the receiving region 108RX of the substrate 104 are further illustrated, illustrating exemplary features of the top metal layer of the substrate 104. For example, in the transmitting region 108TX, numerous via waveguide tops 118TX are located just inside the periphery of region 108TX. Similarly, in the receiving region 108RX, numerous via waveguide tops 118RX are located just inside the diameter of region 108RX. Each via waveguide top 118 is a metal pad of the same shape (e.g., circular) in the top metal layer of the substrate 104. The via waveguide tops 118 are also arranged equally and circumferentially spaced, and the number of tops 118 may be selected according to a particular implementation. The illustrated example has a total of 24 such via waveguide vertices 118, each equally spaced 15 degrees apart from adjacent vertices (360 degrees / 24 vertices = 15-degree spacing). The spacing is applied to the central part of each vertex 118, so that in alternative embodiments, with a higher density and / or larger vertices, each vertex may be in contact with an adjacent vertex. As described below, the entire group of via waveguide vertices in either region 108TX or 108RX collectively provides a tapered waveguide between the region and cable assemblies 106-1 and 106-2, respectively.

[0017] Four antennas are arranged within a circle represented by equally spaced via tops 118TX or 118RX. For example, the transmitting region 108TX has four transmitting antennas 120TX1A, 120TX1B, 120TX2A, and 120TX2B, each having equivalent, generally rectangular (with rounded ends) members that are physically positioned and preferably aligned 90 degrees apart from each other. Similarly, the receiving region 108RX has four receiving antennas 120RX1A, 120RX1B, 120RX2A, and 120RX2B, each preferably positioned 90 degrees apart from each other. As described below, for a set of antennas (either transmitting or receiving), a coupler (e.g., a branch line or other right-angle phase, as in the substrate 104) couples the differential signal between the IC die 102 and an additional feed structure to these antennas, so that a circularly polarized signal is transmitted by or received from the antennas. The signal is further guided by a waveguide including waveguide via tops 118, and therefore the signal is transmitted or received in a generally perpendicular direction from the plane illustrated in Figure 1B (outside the page). Thus, the signal energy is efficiently coupled between the substrate 104 and each cable assembly 106-x.

[0018] Figure 1C is a cross-sectional view of a portion of system 100 taken along line 1C-1C, spanning region 108TX from Figure 1B. A similar view may be presented if taken across region 108RX. Generally, Figure 1C shows a substrate 104 that is physically and electrically connected to a circuit board 122, such as a printed circuit board (PCB). For example, this electrical connection can be achieved using ball grid array (BGA) balls 124 connected to pads 126 on the PCB 122. As described above, the IC die 102 is electrically and physically connected beneath the substrate 104. This electrical connection can be electrically achieved by die bumps, such as copper pillars 128, between the IC conductive area 110 and the contacts (see Figure 1A) along the bottom of the substrate 104, and by physical contact through various die bonding techniques such as thermal compression. An underfill 104UF is also placed between the die 102 and the substrate 104. The vertical dashed lines on the left and right sides of the top of Figure 1C indicate desired positions for the metal waveguide coupler 114-1, which can be mounted relative to the upper surface of the substrate 104, surrounding the transmitting area 108TX, in direct contact with the substrate 104 (and, as described later, with the antenna therein), or with a small air gap (e.g., 0.1 mm) between these two structures.

[0019] The multilayer substrate 104 has a cross-sectional profile that is generally consistent with the evolving technology for substrate packaging. In the illustrated example, the substrate 104 includes six metal layers, referred to in ascending order from the bottom of the substrate 104 as layers L1 through L6. Also, for example, although the metal layer thicknesses can vary, each of the metal layers L1 - L6 can have the same thickness (such as 15 μm), but preferably (for thermal expansion matching), each layer having the same thickness with respect to layers at the same distance from the center core 104C (layers L3 and L4 have the same thickness, layers L2 and L5 have the same thickness, and layers L1 and L6 have the same thickness). There is non-conductive material between consecutive metal layers, which are not referred to as layers in this specification but are (structurally) layered in the same way as between the metal layers. For example, the center core 104C is present between metal layers L3 and L4, which is thicker than the non-conductive material between the other metal layers. Also, for example, the center core 104C can be 200 μm thick, and the non-conductive material between the other metal layers (commonly referred to as build-up 104BU) can be 30 μm thick. The build-up 104BU is preferably a low-loss material, and each layer of such a material has the same or similar dielectric constant. The solder mask 104SM1 is below the metal layer L1, and the solder mask 104SM2 is above the metal layer L6.

[0020] Figure 1C also illustrates an additional structure (within the substrate 104) that forms part of the via waveguide top 118TX in Figure 1B. Specifically, vias 130 are formed via a core 104C, for example, to form a cylindrical void through the central core 104C, which is then filled or plated with a conductive material (e.g., metal), where the void may have a cross-sectional diameter of 90 μm. Vias 130 also provide electrical contact to the metal in layer L3. Above vias 130, the metal layer L4 is patterned to form a pad 132, for example, having a circular circumference and a diameter of 130 μm. A build-up 104BU is formed on the pad 132 (and on other parts of the metal layer L4), and vias 134 are formed within the build-up (for example, by forming a cylindrical void via a build-up on layer L4 and filling or plated with a conductive material). Vias 134 may have a cross-sectional diameter of 60 μm and provide electrical contact to the pad 132. Similarly, above via 134, the metal layer L5 is patterned to form a pad 136 with a smaller diameter (e.g., equal to 100 μm) than pad 132, but with a similar shape. A build-up 104BU is formed on pad 136 (and on other parts of the metal layer L5), and via 138 is formed within its build-up 104BU in the same manner and with the same diameter as via 134. The metal layer L6 is also patterned to form a waveguide crest 118TX, physically and electrically in contact with via 138. Thus, the waveguide crest 118TX is part of a physical structure and an electrical path that includes various items and paths, at least from the metal layer L6 through L3. Furthermore, these structures and paths taper outwards radially from their center as they move upward, with the shape / path beginning to approach the center 108CTR of region 108TX near the bottom of the substrate 104. Referring again to Figure 1B, this same structure is repeated for each waveguide top 118TX. This example has a total of 24 waveguide tops 118TX in the transmitting region 108TX, which are on the inside but close to the periphery, thereby collectively forming a waveguide around the substrate-integrated communication region (either transmitting or receiving).Specifically, each waveguide apex 118TX corresponds to the structure shown in Figure 1C, tapering downwards from the apex and towards the center of the transmitting region. All combinations of such structures across all (e.g., 24) surrounding waveguides generally provide a funnel-shaped physical profile, which is widest at the top of the substrate 104 (e.g., at layer L6) and tapering inwards towards the bottom of the substrate 104 (e.g., at layer L2). Additionally, a roughly circular (or piecewise linear approaching a circle) outer boundary can be defined along the outermost tangent of the circular shape of each waveguide apex 118TX. This outer boundary generally aligns with or coincides with the interior of the surrounding metal waveguide coupler 114-1. Therefore, when a signal is transmitted by antenna 120TX, the funnel-shaped structure provides a waveguide around the region, generally guiding the signal wave vertically from the upper surface of substrate 104 into the interior of metal waveguide coupler 114-1, as shown in Figures 1A and 1C. Such a tapered waveguide can reduce losses when the signal passes between mismatched impedance materials. Such waveguide structures and functionality have been described above with respect to transmitting region 108TX, but receiving region 108RX (in one exemplary embodiment) has the same structure. Thus, when a signal wave is received from metal waveguide coupler 114-2, the signal is guided downward through substrate 104, by the inward tapering of the funnel-shaped waveguide within it, and to IC die 102.

[0021] Figure 1C also illustrates additional feed structures within the substrate 104 that feed the illustrated transmitting antennas 120TX1A and 120TX1B (similarly applicable to antennas 120TX2A and 120TX2B, which are not visible in cross-section). Specifically, vias 140 are formed via a central core 104C, and vias 140 may be formed simultaneously with vias 130, having the same dimensions and material as vias 130 described above in relation to the via waveguide top 118TX. Vias 140 also provide electrical contact to the metal in layer L3 by forming an annular opening in the metal layer L3, so that a metal pad 142 is formed in layer L3, and the metal pad 142 remains in the center of the annular portion, and an open area 142A in the metal layer L3 (which will eventually be filled with buildup) is provided concentrically around the metal pad 142. In this way, the antenna-related structures are isolated from other connections to layer L3 in other circumstances, enabling signal path connections by signal couplers, as described below. In this regard, the metal pad 142 is connected to the conductor portion 144 of the metal layer L2 via via 146. The conductor portion 144 is part of a signal coupler, which communicates with the IC die 102 via additional via 147V and metal layer L1 pad 147P. Returning to via 140, the metal layer L4 is patterned on it to form pad 148, and the metal layer L5 is patterned to form pad 150, and the respective layer L4-L5 and L5-L6 vias 152 and 154 are formed via build-up 104BU, all of which can be formed equivalently and simultaneously to the formation of each metal layer (and build-up) in the horizontally coplanar structure described above in relation to the via waveguide top 118TX. Thus, via 154 provides an electrical contact for transmitting antenna 120TX1A, completing the structure and electrical path for the antenna on the substrate 104. Therefore, below the transmitting antenna 120TX1A on the substrate 104, the overall physical antenna feed structure provides an electrical path through various items and includes at least metal layers L5-L2. Preferably, this structure has a total vertical height λ / 4 from the top of metal layer L2 to the bottom of metal layer L6. Hereinafter, λ is the wavelength of the signal transmitted and received by the coupler 200.Also in this regard, in application examples at even higher frequencies, λ is proportionally reduced such that the antenna height can be reduced and constructed so that the space inside the substrate 104 is reduced. In such examples, rather than being physically attached to the outer surface of the substrate 104 (e.g., the bottom), the extra space of the substrate can be utilized to embed the IC die 102 within the substrate 104. Also, the antenna structure includes a portion closer to the bottom surface of the substrate (pads 142 and vias 140), closer to the center 108CTR of the region 108TX than other portions extending towards the upper surface of the substrate. Such a structure can reduce losses from signal communication and can avoid or minimize the impact of impedance mismatches occurring in the transmission (or reception) signal path. However, since the structure and signal path are considered to be vertically above the substrate 104, the final signal transmission (or reception in the case of the region 108RX) portion of the transmission antenna 120TX1A is at a preferred distance from the transmission antenna 120TX1B (and the other two transmission antennas 120TX2A and 120TX2B), thereby reducing possible crosstalk between the transmission (or reception) signals. Such antenna structures and functionality have been described above with respect to the transmission region 108TX, but (in one exemplary embodiment) the reception region 108RX has the same structure.

[0022] FIG. 1C also illustrates, preferably, additional structures in the substrate 104 that form a signal block structure connecting a metal layer L1, which is normally electrically grounded, to the metal layer L3. Specifically, such a structure includes a metal pad 156 in the layer L1, a via 158 from the metal pad 156 to the layer L2 metal pad 160, and a via 162 from the metal pad 160 to the general plane of the layer L3. Further, as illustrated and described later, this structure is repeated and arranged at a number of selected positions between the four signal antennas.

[0023] Figure 2 is a perspective view of a branch line coupler 200 formed in layer L2 of substrate 104 in one exemplary embodiment. Thus, the coupler 200 structure is formed, for example, by patterning the metal in layer L2 into a desired strip wire, and comprising a build-up 104BU surrounding the L2 structure. As described above in relation to Figure 1B and further described later, the coupler couples the differential signal from IC die 102 to antenna 102TX (and from antenna 102RX to IC die 102 as well), and the branch line coupler 200 is an example of such a coupler. More specifically, the coupler 200 has an input port 202 and an isolation port 204, and two input ports 206 and 208. Input port 202 is connected to output port 206 via a first path member 210, and isolation port 204 is connected to output port 208 via a second path member 212, in this example members 210 and 212 are shown as linear strip wires. A first crossing path member 214 is connected between input port 202 and isolation port 204, and a second crossing path member 216 is connected between output ports 206 and 208. In this example, members 214 and 216 are also shown as linear strip wires. Each of the first path member 210, the second path member 212, the first crossing path member 210, and the second path member 212 has a length LM of λ / 4, where λ is the wavelength of the signal transmitted / received by the coupler 200. Each of the first and second crossing path members 214 and 216 is formed to have the same impedance Z(CM), and each of the first and second path members 210 and 212 is formed to have the same impedance Z(PM), where Z(PM) = Z(CM) / √2. For example, such impedance can be achieved by shaping the first and second path members 210 and 212 to have a width W(PM) that is wider than the matching width W(CM) of the first and second crossing members 214 and 216, respectively.

[0024] Figure 3 is a schematic diagram of the signal path from IC die 102 to the four transmitting antennas 120TX1A, 120TX1B, 120TX2A, and 120TX2B in region 108TX (Figure 1B) via two branch couplers 200-1 and 200-2 (e.g., Figure 2). For reference, the same numbers are reused from Figure 2 to Figure 3, with either a hyphenated 1 or 2 to distinguish the connection to either coupler 200-1 or 200-2. Transceiver 102TXRX (Figure 1A) includes various circuit elements for transmitting and receiving millimeter-wave signals, such as from differential amplifier 102A. Differential amplifier 102A provides differential outputs 102A-1 and 102A-2, which are shown in Figure 3 with their respective (+) and (-) designations, indicating the differential dynamic nature of the outputs and showing that the output signals are out of phase by 180 degrees. Output 102A-1 is connected to input 202-1 of coupler 200-1, and output 102A-2 is connected to input 202-2 of coupler 200-2. The isolated ports 204-1 and 204-2 of couplers 200-1 and 200-2, respectively, are connected to ground via a matched termination impedance (e.g., Z(PM)). Output 206-1 of coupler 200-1 is connected to antenna 120TX2A, and output 208-1 of coupler 200-1 is connected to antenna 120TX1A. Antenna 120TX1A is physically oriented and electrically coupled to provide a signal 90 degrees away from the simultaneous signal from antenna 120TX2A. Output 206-2 of coupler 200-2 is connected to antenna 120TX2B, and output 208-2 of coupler 200-2 is connected to antenna 120TX1B, which is physically and electrically coupled to provide a signal 90 degrees away from the simultaneous signal from antenna 120TX2B.

[0025] The following describes the schematic of the operation shown in Figure 3. Within the IC die 102, the transmitter circuit element generates a millimeter-wave signal WS that is output to the differential amplifier 102A. In response, the amplifier 102A outputs a 180-degree separated version of the input signal (which may be filtered and / or amplified) at its differential outputs 102A-1 and 102A-2. Each of the branch couplers 202-1 and 202-2 receives one input and operates to generate a corresponding 90-degree phase-separated output. With respect to branch coupler 202-1, its two outputs are indicated as 0°(+) and 90°(+), indicating a correspondence to the (+) signal of output 102A-1 and being 90 degrees apart from each other. Thus, output 0°(+) may be perceived as a first unit-length vector located at 0 degrees in the positive direction (usually to the right of the origin in polar coordinates), and output 90°(+) may be perceived as a second unit-length vector located at +90 degrees relative to the first vector. Similarly, with respect to the branch line coupler 200-2, its two outputs are indicated as 0°(-) and 90°(-), corresponding to the (-) signal of output 102A-2, and are 90 degrees apart from each other. Thus, output 0°(-) can be perceived as a third unit length vector located at 0 degrees in the negative direction (usually to the left of the origin in polar coordinates), and output 90°(-) can be perceived as a fourth unit length vector located at either -90 degrees relative to the first vector or +90 degrees relative to the third vector. Thus, in total, Figure 3 encodes the input signal into four waveform vectors equally spaced at a distance of 90 degrees from each other, so that each of the four different 90-degree positions is occupied by its respective waveform vector. Therefore, the four antennas in Figure 3 collectively produce a circularly polarized output, and as the input millimeter-wave signal WS to amplifier 102A fluctuates, each of the four resulting vectors has a constant magnitude, but rotates over time in a plane perpendicular to the plane in which the tops of the transmitting antennas 120TX1A, 120TX1B, 120TX2A, and 120TX2B are aligned. Thus, referring to Figure 1C, the circularly polarized signal rotates vertically upward from the substrate 104 and into the waveguide coupler 114-1. The rotation can be either counterclockwise or clockwise polarization.Similarly, but in the opposite direction, the receiving antennas 120RX1A, 120RX1B, 120RX2A, and 120RX2B are configured to receive four signal components (one per antenna) of a circularly polarized signal from the waveguide coupler 114-1, and these signal components are connected in the reverse direction to components equivalent to those in Figure 3, so as to decode the corresponding output signals representing the received millimeter-wave signal from the signal components.

[0026] Circular polarization achieved by the physical and electrical structures described for one exemplary embodiment offers several advantages. In contrast, for proper signal communication, linear polarization requires fairly precise planar linear matching between the signal and its receiver. Conversely, the provision of the exemplary embodiment of circular polarization eliminates the need for such planar matching. For example, with respect to Figure 1, since the DWG cable assembly 106-x is positioned relative to the substrate 104, the circular cross-section of the cable does not need to be rotationally matched to a specific position relative to the substrate 104 for signal communication. Thus, rotational independence with respect to the axis of each cable is achieved with respect to the transmit / receive structure on the substrate 104. As another example, circularly polarized signals suffer less signal loss in certain environments, such as those with vibration, turns, or gaps in connections.

[0027] Figure 4 is a perspective view of a certain wave transmit / receive signal path component of substrate 104, showing in more detail either the transmit region 108TX or region 108RX of Figure 1B. From Figure 4, and as described above, region 108TX (or 108RX) includes two branch line couplers 200-1 and 200-2 which may be formed in the metal layer L2 (see Figure 1C). Each of the branch line couplers 200-1 and 200-2 is connected to the respective transmit line pairs 400-1A and 400-1B, or 402-1A and 402-1B. Each transmit line pair preferably has first and second portions with a certain angle (e.g., 90 degrees) between these portions. Furthermore, each end of such a pair provides two signals, separated by 90 degrees, to each pair of conductive paths formed by vias and pads (see Figure 1C), thereby providing electrical signal path communication between branch line couplers 200-1 to antennas 120TX2A and 120TX1A, and between branch line couplers 200-2 to antennas 120TX2B and 120TX1B. The perspective view in Figure 4 illustrates that the L6 layer of each antenna has a uniform width except for the rounded ends located above the L4-L5 vias.

[0028] Figure 5 is a perspective view of Figure 4 with additional structures. One of the additions in Figure 5 is a structure that forms a region (either transmit or receive) surrounding waveguide 500, which is generally shown in Figure 5 by concentric dashed ovals. Many via waveguide apex 118TX are located between these ovals, and radially inward tapering vias and pads are connected to each such apex, as shown in Figure 1C. According to this view, the collective funnel-shaped waveguide 500 is based on such structures. Another addition in Figure 5 is a perspective view of multiple signal block structures 502, which include multiple instances of metal layer L2 to L3 connecting structures 156, 158, 160, and 162, as shown in Figure 1C. In the exemplary embodiment, the signal block structures 502 are arranged in a facing Y-pattern between each pair of antennas connected to their respective branch line couplers, and also have fewer (e.g., four) additional structures 502 that bisect the inverted Y-pattern. The grounding structure 502 provides further signal isolation in signal communication between each branch line coupler and the two antennas to which it is connected. Furthermore, structure 502 may be located in an alternative position, and / or other alternatives may be used, such as forms of signal isolation including electromagnetic bandgap (EBG) or high impedance surface (HIS) structures.

[0029] Figure 6 is a plan view of an alternative example of a structure for forming region 108 (either transmit 108TX or receive 108RX), in which the shape of the antenna, branch line coupler, and signal block structure is modified. Thus, alternative exemplary embodiments can be provided by modifying one or more of such structures. For example, alternative branch line couplers 200A1 and 200A-2 are shown having arc-shaped segments (the linear strip lines described above are replaced with rounded signal paths). This is because, in one embodiment of such an example, avoiding bends or other discontinuities in shape can reduce signal loss. In another example, transmit line pairs 400-1A and 400-1B, or 402-1A and 402-1B, are replaced with rounded transmit line pairs 400A-1A and 400A-1B, or 402A-1A and 402A-1B. As another example, the bifurcated inverted Y-shaped pattern of the signal block structure 502 between each pair of antennas connected to each branch line coupler is replaced by the bifurcated H-shaped pattern of the signal block structure 502A. As yet another example, the uniform width of the antennas (except for the rounding above the L6-L5 vias) is replaced by the increasing width (referred to as conical) set of antennas 120ATX1A, 120ATX1B, 120ATX2A, and 120ATX2B.

[0030] From the above, many exemplary embodiments provide millimeter-wave high-speed data communication systems, offering various advantages. For example, different embodiments of the system may include an integrated circuit transceiver with a coupler and antenna embedded in a substrate, where the signal is coupled via one or more couplers that couple the signal to the antenna, and may have various configurations. The embedded substrate device provides a waveguide launch configured to radiate the electromagnetic signal in a relatively narrowly controlled direction away from the substrate, such as away from its surface, and to couple to one or more DWG cable assemblies. The cable assemblies may include dielectric material and may provide dielectric waveguides at the ends of the cable assemblies for further communication of the electromagnetic signal to and from the device. The electromagnetic signal may also be communicated as a circularly polarized signal, given the advantages of the described structure and such signals, such as reduced signal loss and reduced need for precise matching at the termination of the cable carrying the signal. Furthermore, the exemplary embodiment can reduce group delay, which is a measure of the delay of each different frequency component of a signal as the signal passes through the device or system, where ideally these delays are equal or nearly equal, providing a relatively flat group delay response curve. However, dielectric waveguide cables may have a non-flat group delay response, but the exemplary embodiment provides an offset non-flat group delay response, and therefore, a combination of substrate 104 having such cables provides a flatter overall system group delay over a desired millimeter-wave bandwidth. Further modifications of the described embodiment are possible within the claims, and other embodiments are possible.

Claims

1. It is a wave communication system, Integrated circuits and A multilayer substrate electrically coupled to the aforementioned integrated circuit, An antenna structure configured to transmit circularly polarized waves in response to a signal from the integrated circuit, comprising a first, second, third, and fourth antenna, each antenna oriented at the same angle with respect to an adjacent antenna, Antenna vias coupled to the first, second, third, and fourth antennas, A waveguide configured to guide the circularly polarized waves away from a certain region, comprising a plurality of waveguide members spaced circumferentially around the first, second, third, and fourth antennas, wherein each of the plurality of waveguide members comprises its respective waveguide via and its respective waveguide top, The multilayer substrate includes the above, The multilayer substrate further includes an additional feed structure, and this additional feed structure is A first level metal layer including a first region for connecting the integrated circuit, A second level metal layer including a first region for connecting waveguide vias at the end of the waveguide member and a second region for connecting antenna vias, A wave communication system comprising a third level metal layer formed between the first level metal layer and the second level metal layer, wherein the third level metal layer includes a coupling structure configured to provide circular polarization to the antenna structure.

2. The system according to Claim 1, A system wherein the waveguide member further includes first and second waveguide vias, the first waveguide via being located a first distance from the center of the region, the second waveguide via being located a second distance from the center of the region, the first waveguide via being located a third distance from the top surface of the multilayer substrate, the second waveguide via being located a fourth distance from the top surface of the multilayer substrate, the first distance being less than the second distance, and the fourth distance being less than the third distance.

3. The system according to claim 1, A system further comprising a waveguide member having a structure that tapers from the center of the region as it approaches the upper surface of the multilayer substrate.

4. The system according to claim 1, The first antenna is electrically coupled to a feed portion at a first distance from the bottom surface of the multilayer substrate and to an additional feed portion at a second distance from the bottom surface of the multilayer substrate. The feed portion is at a third distance from the center of the region, and the additional feed portion is at a fourth distance from the center of the region. A system in which the second distance is smaller than the first distance and the third distance is smaller than the fourth distance.

5. The system according to claim 1, A system in which the first antenna includes a member that is oriented 90 degrees away from the member of the second antenna.

6. The system according to claim 1, The multilayer substrate further includes a signal block structure disposed between adjacent antennas, wherein the signal block structure electrically connects a first region of the second level metal layer with a second region of the first level metal layer spaced apart from the first region.

7. The system according to claim 1, A system wherein the third-level metal layer of the bonding structure is electrically connected via vias to the second region of the second-level metal layer and to the first region of the first-level metal layer.

8. The system according to claim 7, The coupling structure includes a first branch line coupler coupled to the first and second antennas, and a second branch line coupler coupled to the third and fourth antennas.

9. The system according to claim 8, A system comprising the first branch line coupler and the second branch line coupler, each including a linear strip wire.

10. The system according to claim 8, A system in which the first branch line coupler and the second branch line coupler each include an arc-shaped strip wire.

11. The system according to claim 8, A system in which the signal from the integrated circuit includes a differential signal having a first signal on a first line and a second signal on a second line, the first line being coupled to the first branch line coupler and the second line being coupled to the second branch line coupler.

12. The system according to claim 1, A system in which the multilayer substrate is configured to be coupled to a cable assembly including a dielectric cable and a waveguide coupler.

13. The system according to claim 1, The antenna structure is further configured to transmit the circularly polarized waves away from the upper surface of the multilayer substrate, A system in which the integrated circuit is physically mounted on the bottom surface of the multilayer substrate, and the bottom surface faces the top surface.

14. It is a wave communication system, Integrated circuits and A multilayer substrate electrically coupled to the aforementioned integrated circuit and configured to communicate circularly polarized waves between the integrated circuit and the cable, A plurality of antennas, wherein each of the plurality of antennas is oriented at the same angle with respect to an adjacent antenna, A waveguide having a plurality of waveguide members spaced circumferentially around the plurality of antennas, wherein each of the plurality of waveguide members includes its respective waveguide via and its respective waveguide top, The multilayer substrate including, A waveguide coupler on the multilayer substrate and on the waveguide and the plurality of antennas, the waveguide coupler being adapted to be coupled to a cable, The multilayer substrate further includes an additional feed structure, and this additional feed structure is A first level metal layer including a first region for connecting the integrated circuit, A second level metal layer including a first region for connecting waveguide vias at the end of the waveguide member and a second region for connecting antenna vias coupled to the antenna, A wave communication system comprising a third level metal layer formed between the first level metal layer and the second level metal layer, wherein the third level metal layer includes a coupling structure configured to provide circular polarization to the antenna structure.

15. The system according to claim 14, A system comprising a multilayer substrate configured to communicate circularly polarized waves, wherein the structure comprises a feed structure and a plurality of antennas, the plurality of antennas being electrically coupled to each of the feed structures.

16. The system according to claim 14, A system wherein the waveguide is further configured to communicate the circularly polarized waves through the multilayer substrate.

17. The system according to claim 14, The multilayer substrate further includes a structure configured to communicate the circularly polarized waves, the structure includes a feed structure and a plurality of antennas, the plurality of antennas being electrically coupled to each of the feed structures. A system in which the waveguide is configured to communicate the circularly polarized waves via the multilayer substrate.

18. The system according to claim 17, A system in which the feed structure has a tapered shape between the bottom surface of the multilayer substrate adjacent to the integrated circuit and the top surface of the multilayer substrate away from the bottom surface.

19. It is a wave communication system, Integrated circuits and Multilayer substrate, The antenna feed structure coupled to the aforementioned integrated circuit, A plurality of antenna elements coupled to each of the antenna feed structures, wherein each of the plurality of antenna elements is oriented at the same angle with respect to an adjacent antenna element, A waveguide configured to guide waves away from a certain region, having a plurality of waveguide members spaced circumferentially around a plurality of antenna elements, each of the plurality of waveguide members including its respective waveguide via and its respective waveguide top, The multilayer substrate includes the above, The multilayer substrate further includes an additional feed structure, and this additional feed structure is A first level metal layer including a first region for connecting the integrated circuit, A second level metal layer including a first region for connecting waveguide vias at the end of the waveguide member and a second region for connecting antenna vias coupled to the antenna, The antenna structure includes a third level metal layer formed between the first level metal layer and the second level metal layer, wherein the third level metal layer includes a coupling structure configured to provide circular polarization to the antenna structure. A wave communication system in which the third level metal layer is electrically connected via vias to the second region of the second level metal layer and to the first region of the first level metal layer.

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