The present invention relates to radio communication systems and, more particularly, to base station antennas (BSAs) utilized in cellular and other communication systems.
Multi-port directional radio frequency (RF) hybrid couplers may be used to fulfill a variety of different roles within base station antenna (BSA) systems, as disclosed in commonly assigned Chinese Patent No. ZL201810242591.1, entitled “Cellular Communication Systems Having Antenna Arrays Therein with Enhanced Half Power Beam Width (HPBW) Control,” and in commonly assigned Chinese Patent Application No. 202211256676.8, entitled “Massive MIMO Base Station Antenna Systems Having Hybrid Couplers Therein,” the disclosures of which are hereby incorporated herein by reference. One example of such a BSA-compatible four-port hybrid coupler 100 includes a rectangular substrate 20 (e.g., printed circuit board (PCB)) having top and bottom surfaces thereon, as illustrated by
The first primary trace 10a includes a plurality of trace segments electrically connected in series between a first port (Port 1) and a second port (Port 2) of the coupler 100; whereas the second primary trace 10b includes a plurality of trace segments electrically connected in series between a fourth port (Port 4) and a third port (Port 3) of the coupler 100. The first coupled trace 12a includes a series combination of trace segments (and metal jumper 12c) that span the substrate 20 from adjacent Port 1 (and a first end of the first primary trace 10a) to adjacent Port 3 (and a second end of the second primary trace 10b); whereas the second coupled trace 12b includes a series combination of trace segments that span the substrate 20 from adjacent Port 4 (and a first end of the second primary trace 10b) to adjacent Port 2 (and second end of the first primary trace 10a). Moreover, based on the illustrated patterning of the primary and coupled traces, the first primary trace 10a is configured as a mirror-image of the second primary trace 10b relative to a first centerline CL1 extending along a longitudinal axis of the substrate 20, and the first coupled trace 12a is configured as a mirror-image of the second coupled trace 12b relative to the first centerline CL1 as well as a second centerline CL2 extending along a transverse axis of the substrate 20.
A BSA-compatible, compact, four-port radio-frequency (RF) hybrid coupler according to some embodiments of the invention includes a substrate, and first and second primary traces and first and second coupled traces on a first surface of the substrate. The first primary trace has first and second ends electrically coupled to first and second ports of the coupler, respectively, and the second primary trace has first and second ends electrically coupled to fourth and third ports of the coupler, respectively. The first coupled trace has: (i) a first end including a plurality of trace segments connected in series, which collectively provide a first degree of RF coupling to the first end of the first primary trace adjacent the first port when the coupler is active, and (ii) a second end including a plurality of trace segments connected in series, which collectively provide a third degree of RF coupling to the second end of the second primary trace adjacent the third port when the coupler is active; the first coupled trace is configured such that the third degree of RF coupling is unequal to the first degree of RF coupling. The second coupled trace has: (i) a first end including a plurality of trace segments connected in series, which collectively provide a fourth degree of RF coupling to the first end of the second primary trace adjacent the fourth port when the coupler is active, and (ii) a second end including a plurality of trace segments connected in series, which collectively provide a second degree of RF coupling to the second end of the first primary trace adjacent the second port when the coupler is active; the second coupled traces is configured such that the second degree of RF coupling is unequal to the fourth degree of RF coupling.
In some of these embodiments, the first and fourth ports extend adjacent a first side of the substrate, and the second and third ports extend adjacent a second side of the substrate, opposite the first side. Advantageously, the substrate may be a relatively small rectangular-shaped substrate having lateral dimensions of less than about 130 mm (length) by less than about 75 mm (width) to yield an area of less than about 10,000 mm2. In addition, the first end of the first coupled trace may be configured as a mirror-image of a first end of the second coupled trace, relative to a first centerline extending between the first and second primary traces, and the second end of the first coupled trace may be configured as a mirror-image of a second end of the second coupled trace, relative to the first centerline. However, to achieve the above-described asymmetric coupling characteristics between the first and third ports and between the second and fourth ports, the first end of the first coupled trace may not be a mirror-image of a second end of the second coupled trace, relative to a second centerline extending between the first and second ports of the coupler, and the first end of the second coupled trace may not be a mirror-image of a second end of the first coupled trace, relative to the second centerline.
According to another embodiment of the invention, the first coupled trace may be configured to include a first pair of serpentine-shaped trace segments, which are electrically coupled in series with each other. Likewise, the second coupled trace may be configured to include a second pair of serpentine-shaped trace segments, which are electrically coupled in series with each other. In some embodiments, either the first pair of serpentine-shaped trace segments may be electrically connected end-to-end by an electrically conductive jumper, which is spaced above the first surface of the substrate, or the second pair of serpentine-shaped trace segments may be electrically connected end-to-end by the electrically conductive jumper. In addition, the first pair of serpentine-shaped trace segments may extend in series and between the first and second ends of first coupled trace, and the second pair of serpentine-shaped trace segments may extend in series and between the first and second ends of second coupled trace.
According to further embodiments of the invention, the first end of the first primary trace may include first and second linear trace segments that are joined together by an elbow-shaped trace segment, and the first end of the first coupled trace may also include first and second linear trace segments that are joined together by an elbow-shaped trace segment. Moreover, the first and second linear trace segments within the first primary trace may extend parallel to the first and second linear trace segments within the first coupled trace, respectively.
According to additional embodiments of the invention, a ground plane may be provided on a second surface of the substrate, and this ground plane may include a “defected” ground structure (DGS) as an opening therein that improves coupling between an end of a primary trace and an end of a corresponding coupled trace. In some embodiments, this DGS may be configured as a polygonal-shaped opening within the ground plane, and in other embodiments the DGS may be configured as a rectangular-shaped, ladder-shaped or similar opening that extends opposite a parallel combination of the second linear trace segment within the first primary trace and the second linear trace segment within the first coupled trace. And, in other embodiments, a dielectric loading element, such as a rectangular-shaped loading element, may be provided that covers at least a portion of a parallel combination of the second linear trace segment within the first primary trace and the second linear trace segment within the first coupled trace. A first pair of phase delay lines may also be provided, which are electrically connected to spaced-apart locations on the first primary trace, and a second pair of phase delay lines may be provided, which are electrically connected to spaced-apart locations on the second primary trace. In addition, terminal ends of each of the first pair of phase delay lines and terminal ends of each of the second pair of phase delay lines may be electrically shorted through the substrate to the ground plane on the second surface of the substrate.
In still further embodiments of the invention, a four-port radio-frequency (RF) hybrid coupler may include a substrate, and first through fourth power dividers on the substrate, which have corresponding first through fourth input ports that correspond to first through fourth ports of the coupler, and corresponding first through fourth pairs of output ports. A first primary trace is provided on the substrate, which electrically connects a first output port of the first power divider to a first output port of the second power divider. A second primary trace is provided on the substrate, which electrically connects a first output port of the fourth power divider to a first output port of the third power divider. A first coupled trace is provided, which electrically connects a second output port of the first power divider to a second output port of the third power divider, and a second coupled trace is provided, which electrically connects a second output port of the fourth power divider to a second output port of the second power divider. In some embodiments, a layout of the first power divider is a mirror-image of a layout of the fourth power divider, relative to a first centerline of the substrate, which extends between the first and second power dividers on one side and the fourth and third power dividers on another side. In addition, a layout of the second power divider is a mirror-image of a layout of the third power divider, relative to the first centerline. The layout of the first power divider may also be a mirror-image of the layout of the second power divider, relative to a second centerline of the substrate, which extends between the first and fourth power dividers on one side and the second and third power dividers on another side. The layout of the fourth power divider may also be a mirror-image of the layout of the third power divider, relative to the second centerline.
According to additional embodiments of the invention, the first and second primary traces may be configured as mirror-images of each other relative to the first centerline, and the first and second coupled traces may be configured as mirror-images of each other relative to the first centerline. In addition, an electrically conductive jumper is provided, which enables the first coupled trace to jump over the second coupled trace, or vice versa. In some embodiments, the first through fourth power dividers may be configured as single-section Wilkinson power dividers or as multi-section Wilkinson power dividers, which may each include first section with trace segments having a first width and a second section with trace segments having a second width greater than the first width.
Still further embodiments of the invention may include a four-port radio-frequency (RF) hybrid coupler having a pair of primary traces, a pair of coupled traces and a pair of energy cancellation circuits therein. According to these embodiments, a first primary trace is provided on a first surface of the substrate, and has first and second ends electrically coupled to first and second ports of the RF hybrid coupler, respectively. Similarly, a second primary trace is provided on the first surface of the substrate, and has first and second ends electrically coupled to fourth and third ports of the RF hybrid coupler, respectively. A first coupled trace, which is provided on the first surface of the substrate, includes: (i) a first end configured to provide a first degree of RF coupling to the first end of the first primary trace adjacent the first port when the RF hybrid coupler is active, and (ii) a second end configured to provide a third degree of RF coupling to the second end of the second primary trace adjacent the third port when the RF hybrid coupler is active. A second coupled trace, which is provided on the first surface of the substrate, includes: (i) a first end configured to provide a fourth degree of RF coupling to the first end of the second primary trace adjacent the fourth port when the RF hybrid coupler is active, and (ii) a second end configured to provide a second degree of RF coupling to the second end of the first primary trace adjacent the second port when the RF hybrid coupler is active. Advantageously, a first energy cancellation circuit (ECC) is provided, which includes a first termination coupler having an input port electrically coupled to the second end of the second coupled trace; and a second ECC is provided, which includes a second termination coupler having an input port electrically coupled to the second end of the first coupled trace. In some of these embodiments, the first termination coupler is configured as a four-port coupler having through, coupling and isolation ports terminated by respective resistors. In some embodiments, the resistors terminating the through and coupling ports of the first termination coupler may be relatively high-power resistors, and the resistor terminating the isolation port may be a relatively low-power resistor. The first termination coupler may also be selected from a group consisting of: 3 dB branch-line couplers and 3 dB coupled-line couplers. According to further embodiments, the first and second termination couplers may have matching gain and phase characteristics.
The present invention now will be described more fully with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout.
It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present invention. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprising”, “including”, “having” and variants thereof, when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. In contrast, the term “consisting of” when used in this specification, specifies the stated features, steps, operations, elements, and/or components, and precludes additional features, steps, operations, elements and/or components.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Referring now to
Advantageously, these reduced dimensions may be achieved by locating a pair of ports on each side of the substrate 220 closer together and then using 90° and elbow-shaped trace segments within the first and second primary traces 210a, 210b and corresponding first and second coupled traces 212a, 212b to obtain a smaller overall trace layout “footprint” (while maintaining sufficient primary and coupled trace length), as described hereinbelow. The illustrated layout footprint may also be best suited for RF frequencies in a band from about 696 MHz to about 960 MHz, however, other frequency bands may also be used.
In addition, the first primary trace 210a has first and second ends electrically connected to first and second ports of the coupler 200, respectively, which are shown as Port 1 and Port 2, and the second primary trace 210b has first and second ends electrically connected to fourth and third ports of the coupler 200, respectively, which are shown as Port 4 and Port 3. The first coupled trace 212a has a first end that is RF coupled to the first end of the first primary trace 210a (adjacent Port 1) and a second end that is RF coupled to the second end of the second primary trace 210b (adjacent Port 3). Similarly, the second coupled trace 212b has a first end that is RF coupled to the first end of the second primary trace 210b (adjacent Port 4) and a second end that is RF coupled to the second end of the first primary trace 210a (adjacent Port 2). Moreover, as will be understood by those skilled in the art, each of the primary and coupled traces is configured as a corresponding plurality of metal trace segments of different shapes, lengths and widths, which are electrically connected in series between their respective ends, as shown.
Thus, in the illustrated embodiment, the first primary trace 210a is configured to include the following trace segments: a first port segment 2a, a first linear segment 2b, a first elbow-shaped segment 2c, a second linear segment 2d, a third linear segment 2e, a fourth linear segment 2f, a second elbow-shaped segment 2g, a fifth linear segment 2h, and a second port segment 2i. In addition, the first port segment 2a and the first linear segment 2b are joined by a 90° corner segment, the second linear segment 2d and third linear segment 2e are joined by a pair of 90° corner segments, the third linear segment 2e and fourth linear segment 2f are joined by a pair of 90° corner segments, and the fifth linear segment 2h and the second port segment 2i are joined by a 90° corner segment, as illustrated. Likewise, the second primary trace 210b, which is a mirror-image of the first primary trace 210a (about a first centerline CL1), is configured to include the following trace segments: a fourth port segment 4a, a first linear segment 4b, a first elbow-shaped segment 4c, a second linear segment 4d, a third linear segment 4e, a fourth linear segment 4f, a second elbow-shaped segment 4g, a fifth linear segment 4h, and a third port segment 4i. In addition, the fourth port segment 4a and the first linear segment 4b are joined by a 90° corner segment, the second linear segment 4d and third linear segment 4e are joined by a pair of 90° corner segments, the third linear segment 4e and fourth linear segment 4f are joined by a pair of 90° corner segments, and the fifth linear segment 4h and the third port segment 4i are joined by a 90° corner segment, as illustrated.
Referring still to
Likewise, the second coupled trace 212b has: (i) a first end including a plurality of trace segments connected in series, which collectively provide a fourth degree of RF coupling to the first end of the second primary trace 210b adjacent Port 4 when the coupler 200 is active, and (ii) a second end including a plurality of trace segments connected in series, which collectively provide a second degree of RF coupling to the second end of the first primary trace 210a adjacent Port 2 when the coupler 200 is active. In addition, the first and second ends of the second coupled trace 212b are configured differently/asymmetrically such that the fourth degree of RF coupling is preferably less than the second degree of RF coupling.
In particular, the first end of the first coupled trace 212a is configured to include the following trace segments: a first end termination 6a, a first linear segment 6b, which is connected to the first end termination 6a by a resistor R, a first elbow-shaped segment 6c, a second linear segment 6d, a second elbow-shaped segment 6e, and a first serpentine-shaped segment 6f. In contrast, the second end of the first coupled trace 212a is configured to include the following trace segments: a pair of end terminations 6p, 6p′, which are electrically coupled by resistors R and unequal length metal traces 60, 60′ to a relatively wide first linear segment 6n, a second linear segment 6m, which is electrically connected by a pair of 90° corner segments to the relatively wide first linear segment 6n, a third linear segment 6l, which is electrically connected by a pair of 90° corner segments to the second linear segment 6m, a first elbow-shaped segment 6k, a fourth linear segment 6j, a second elbow-shaped segment 6i, and a second serpentine-shaped segment 6h, which is electrically connected by a jumper segment 6g to the first serpentine-shaped segment 6f. Advantageously, these paired serpentine-shaped segments have a slow wave characteristic that provides for sufficient phase compensation.
Similarly, the first end of the second coupled trace 212b is configured to include the following trace segments: a first end termination 8a, a first linear segment 8b, which is connected to the first end termination 8a by a resistor R, a first elbow-shaped segment 8c, a second linear segment 8d, a second elbow-shaped segment 8e, and a first serpentine-shaped segment 8f. In contrast, the second end of the second coupled trace 212b is configured to include the following trace segments: a pair of end terminations 8p, 8p′, which are electrically coupled by resistors R and unequal length metal traces 8o, 8o′ to a relatively wide first linear segment 8n, a second linear segment 8m, which is electrically connected by a pair of 90° corner segments to the relatively wide first linear segment 8n, a third linear segment 8l, which is electrically connected by a pair of 90° corner segments to the second linear segment 8m, a first elbow-shaped segment 8k, a fourth linear segment 8j, a second elbow-shaped segment 8i, and a second serpentine-shaped segment 8h, which is electrically connected (without a jumper segment) to the first serpentine-shaped segment 8f; however, the placement of the jumper segment 6g may be reversed between the first and second coupled traces in an alternative embodiment.
Based on these illustrated configurations of the first and second coupled traces 212a, 212b a mirror-image equivalency is present between the first coupled trace 212a and the second coupled trace 212b relative to the first centerline CL1. Nonetheless, an asymmetry in the degree of coupling is present between the ends of the first and second coupled traces 212a, 212b relative to the corresponding ends of the first and second primary traces 210a, 210b (and corresponding ports) because a mirror-image equivalency is not present between the first coupled trace 212a and the second coupled trace 212b relative to a second centerline CL2, which is located equidistant from Port 1, Port 4 on one side of the substrate 220 and Port 2, Port 3 on an opposite side of the substrate 220.
Next, as shown by
Referring now to
Furthermore, as illustrated by
Referring now to
In particular, as shown by
In addition, a first primary trace 410a is provided, which electrically connects a first output port 402a of the first power divider 450a to a first output port 402b of the second power divider 450b, and a second primary trace 410b is provided, which electrically connects a first output port 402d of the fourth power divider 450d to a first output port 402c of the third power divider 450c. A first coupled trace 412a is provided, which electrically connects a second output port 402a′ of the first power divider 450a to a second output port 402c′ of the third power divider 450c (via a jumper segment 414), and a second coupled trace 412b is provided, which electrically connects a second output port 402d′ of the fourth power divider 450d to a second output port 402b′ of the second power divider 450b. As shown, the first and second primary traces 410a, 410b and the first and second coupled traces 412a, 412b are mirror images of each other about a first centerline CL1 of the substrate 420, as shown. And, the first and second coupled traces 412a, 412b are mirror images of each other about a second centerline CL2 of the substrate, as shown.
Referring now to
Referring now to
According to some embodiments of the invention, the first and second energy cancellation circuits ECC1, ECC2 are each configured as a corresponding 4-port “termination” coupler 502 with 3-port resistive termination provided by resistors R2, R3 and R4 at Ports 2, 3 and 4, respectively, as shown by
In particular, the 4-port “termination” coupler 502 may be configured such that: Port 1 is the input port IN, which is electrically connected to an end of the corresponding coupled trace 212a/312a, 212b/312b, Ports 2 and 3 are the through-port and coupling-port, respectively, which have −3 dB amplification and 90° phase shift and are connected to relatively high power resistors R2, R3 for termination, and Port 4 is the isolation port (ISO) associated with reduced energy, which only requires a relatively low power resistor R4 for termination.
Thus, as illustrated by
Referring now to
Referring now to
In the drawings and specification, there have been disclosed typical preferred embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being set forth in the following claims.
Number | Date | Country | Kind |
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202211623239.5 | Dec 2022 | CN | national |