Differential segmented aperture

Abstract

To provide a suitable differential segmented aperture.SOLUTION: A radio frequency (RF) aperture includes an interface printed circuit board. An array of electrically conductive tapered projections has bases that are disposed on a front side of the interface printed circuit board and extend away from the front side of the interface printed circuit board. Chip baluns are mounted on the back side of the interface printed circuit board. Each chip balun has a balanced port electrically connected with (two) neighboring electrically conductive tapered projections via electrical feedthroughs passing through the interface printed circuit board. Each chip balun further has an unbalanced port, and RF circuitry disposed at the back side of the interface printed circuit board is electrically connected with the unbalanced ports of the chip baluns. The electrically conductive tapered projections include dielectric tapered projections and an electrically conductive layer disposed on inner or outer surfaces of the dielectric tapered projections.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This application claims the benefit of U.S. Provisional Application No. 62 / 839,121, filed Apr. 26, 2019, entitled "DIFFERENTIAL SEGMENTED APERTURE". U.S. Provisional Application No. 62 / 839,121, filed Apr. 26, 2019, is hereby incorporated by reference in its entirety.

[0002] (Background) The following relates to the field of radio frequency (RF) technology, RF transmitter technology, RF receiver technology, RF transceiver technology, broadband RF transmitter, receiver, and / or transceiver technology, RF communication technology, and related technologies.

[0003] Steinbrecher's U.S. Patent No. 7,420,522, entitled "Electromagnetic Radiation Interface System and Method", discloses a broadband RF aperture as follows. "An electromagnetic radiation interface suitable for use in combination with radio frequencies is provided. The surface comprises a plurality of metallic conical bristles. A corresponding plurality of termination segments are provided such that each bristle is terminated with a termination segment. The termination segments may capture substantially all of the electromagnetic wave energy received by each individual bristle and thereby have an electrical resistance to prevent reflection from the surface of the interface. Each termination segment may also include an analog / digital converter for converting the energy from each bristle into a digital word. The bristles may be mounted on a ground plane having a plurality of holes therethrough. A plurality of coaxial transmission lines may extend through the ground plane to interconnect the plurality of bristles to the plurality of termination segments."

[0004] Some improvements are disclosed herein.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Means for Solving the Problems

[0006] (Brief Summary) According to some exemplary embodiments, a radio frequency (RF) aperture is disclosed. An interface printed circuit board has a front side and a back side. An array of conductive tapered protrusions has a base disposed on the front side of the interface printed circuit board and extends away from the front side of the interface printed circuit board. Chip baluns are mounted on the back side of the interface printed circuit board. Each chip balun has a balanced port that is electrically connected to two adjacent conductive tapered protrusions of the array of conductive tapered protrusions via an electrical feedthrough passing through the interface printed circuit board. Each chip balun further has an unbalanced port. An RF circuitry is disposed on the back side of the interface printed circuit board and is electrically connected to the unbalanced port of the chip balun.

[0007] According to some exemplary embodiments disclosed herein, a method of manufacturing a radio frequency (RF) aperture includes coating a surface of a dielectric tapered protrusion with a conductive layer to form a conductive tapered protrusion, mounting the conductive tapered protrusion on the front side of an interface printed circuit board, mounting an RF circuitry on the interface printed circuit board and / or on a second printed circuit board mounted in parallel with the interface printed circuit board, and electrically connecting the RF circuitry to the conductive tapered protrusion.

[0008] According to some exemplary embodiments disclosed herein, an RF aperture comprises an interface printed circuit board having a front side and a back side, an array of conductive tapered protrusions, and an RF circuit network. The conductive tapered protrusions have a base disposed on the front side of the interface printed circuit board and extend away from the front side of the interface printed circuit board. The conductive tapered protrusions comprise a dielectric tapered protrusion and a conductive layer disposed on the surface of the dielectric tapered protrusion. The RF circuit network is disposed on the back side of the interface printed circuit board and is electrically connected to the array of conductive tapered protrusions via an electrical feedthrough passing through the interface printed circuit board. In some embodiments, the RF circuit network further includes a balun with balanced ports that connect pairs of adjacent conductive tapered protrusions within the array of conductive tapered protrusions via electrical feedthroughs passing through the interface printed circuit board. This specification also provides, for example, the following items. (Item 1) A radio frequency (RF) aperture, comprising: an interface printed circuit board having a front side and a back side; an array of conductive tapered protrusions having a base disposed on the front side of the interface printed circuit board and extending away from the front side of the interface printed circuit board; a balun mounted on the back side of the interface printed circuit board, each balun having balanced ports electrically connected to two adjacent conductive tapered protrusions of the array of conductive tapered protrusions via an electrical feedthrough passing through the interface printed circuit board, and each balun further having an unbalanced port; an RF circuit network disposed on the back side of the interface printed circuit board and electrically connected to the unbalanced port of the balun; and an RF aperture comprising the same. (Item 2) The balun includes a chip balun, and the RF circuit network includes electronic components mounted on the back side of the interface printed circuit board, the RF aperture according to item 1. (Item 3) The RF aperture further includes a second printed circuit board arranged parallel to the interface printed circuit board and facing the back side of the interface printed circuit board. The RF circuit network includes electronic components mounted on the second printed circuit board, the RF aperture according to any one of items 1-2. (Item 4) The RF circuit network includes an RF power splitter / combiner that connects one or more combinations of the unbalanced ports of the balun to one or more RF connectors, the RF aperture according to any one of items 1-3. (Item 5) The RF power splitter / combiner is interconnected as a plurality of RF sub-assemblies, and each RF sub-assembly connects four or more subsets of the unbalanced ports of the balun to a single RF connector, the RF aperture according to item 4. (Item 6) The RF circuit network further includes a plurality of analog / digital (A / D) converters. The RF power splitter / combiner is interconnected as a plurality of RF sub-assemblies, and each RF sub-assembly connects four or more subsets of the unbalanced ports of the balun to a single analog / digital (A / D) converter, the RF aperture according to item 4. (Item 7) The RF circuit network includes a signal conditioning circuit connected to each unbalanced port of the balun, and the signal conditioning circuit connected to each unbalanced port includes an RF transmission amplifier, an RF reception amplifier, an RF switching circuit network configured to switch between a transmission mode in which the RF transmission amplifier is operably connected to the unbalanced port and a reception mode in which the RF reception amplifier is operably connected to the unbalanced port and includes the RF aperture according to any one of items 1-6. (Item 8) The RF circuit network includes a beam steering circuit network configured to operate the RF aperture as a phased array directive RF transmitter and / or a phased array directive RF receiver, the RF aperture according to any one of items 1-7. (Item 9) The array of conductive tapered protrusions includes dielectric tapered protrusions, and a conductive layer disposed on the surface of the dielectric tapered protrusions, the RF aperture according to any one of items 1-8. (Item 10) The RF aperture according to item 9, comprising a dielectric plate including the dielectric tapered protrusions. (Item 11) The dielectric tapered protrusions are hollow, and the conductive layer is disposed on the outer surface or the inner surface of the hollow dielectric tapered protrusions, the RF aperture according to any one of items 9-10. (Item 12) A method of manufacturing a radio frequency (RF) aperture, comprising: coating the surface of the dielectric tapered protrusions with a conductive layer to form conductive tapered protrusions; mounting the conductive tapered protrusions on the front side of an interface printed circuit board; mounting an RF circuit network on the interface printed circuit board and / or on a second printed circuit board mounted in parallel with the interface printed circuit; electrically connecting the RF circuit network to the conductive tapered protrusions; the method. (Item 13) The dielectric tapered protrusions are integral with the surface of a dielectric plate and extend away from the surface of the dielectric plate, and the coating includes coating the dielectric plate including at least the integral dielectric tapered protrusions, and the method further includes After said coating, etching the coating away from the plate between the conductive tapered protrusions to insulate the conductive tapered protrusions from each other DC, or Before said coating, depositing a mask material on the plate between the conductive tapered protrusions such that the coating does not coat the plate between the conductive tapered protrusions, whereby the conductive tapered protrusions are insulated from each other DC The method according to item 12, including one of the above. (Item 14) Mounting the RF network includes mounting a balun on the back side of the interface printed circuit board, Said electrically connecting includes electrically connecting each balanced port of the balun to two of the conductive tapered protrusions via an electrical feed-through passing through the interface printed circuit board. The method according to any one of items 12-13. (Item 15) A radio frequency (RF) aperture, An interface printed circuit board having a front side and a back side, An array of conductive tapered protrusions having a base disposed on the front side of the interface printed circuit board and extending away from the front side of the interface printed circuit board, the conductive tapered protrusions comprising a dielectric tapered protrusion and a conductive layer disposed on the surface of the dielectric tapered protrusion, the array of conductive tapered protrusions, An RF network disposed on the back side of the interface printed circuit board and electrically connected to the array of conductive tapered protrusions via an electrical feed-through passing through the interface printed circuit board Comprising an RF aperture. (Item 16) An RF aperture according to item 15, comprising a dielectric plate including the dielectric tapered protrusions, wherein the conductive layer does not coat the part of the plate between the dielectric tapered protrusions such that the dielectric tapered protrusions are DC-insulated from each other. (Item 17) An RF aperture according to any one of items 15 - 16, wherein the dielectric tapered protrusions are hollow. (Item 18) An RF aperture according to any one of items 15 - 17, comprising electronic components mounted on the back side of the interface printed circuit board. (Item 19) Further comprising a second printed circuit board arranged parallel to the interface printed circuit board and facing the back side of the interface printed circuit board, An RF aperture according to any one of items 15 - 18, comprising electronic components mounted on the second printed circuit board. (Item 20) An RF aperture according to any one of items 15 - 19, wherein the RF circuit network includes a balun with balanced ports that connects pairs of adjacent conductive tapered protrusions within the array of conductive tapered protrusions via the electrical feed-through passing through the interface printed circuit board. (Item 21) An RF aperture according to item 20, wherein the RF circuit network further includes a first-level RF power divider / combiner that connects the unbalanced ports of two baluns respectively. (Item 22) An RF aperture according to item 21, wherein the RF circuit network further includes a second-level RF power divider / combiner that connects two first-level RF power dividers / combiners respectively. (Item 23) The RF circuit network further includes a signal conditioning circuit connected to the unbalanced ports of each balun, and the signal conditioning circuit includes an RF transmission amplifier, and an RF reception amplifier, An RF switching circuit network configured to switch between a transmission mode in which the RF transmission amplifier is operably connected to the unbalanced port and a reception mode in which an RF reception amplifier is operably connected to the unbalanced port The RF aperture according to any one of items 20 - 22, including (Item 24) The RF aperture according to any one of items 15 - 23, wherein the RF circuit network includes a beam steering circuit network configured to operate the RF aperture as a phased array directional RF transmitter and / or a phased array directional RF receiver

Brief Description of the Drawings

[0009] Any quantitative dimensions shown in the drawings are to be understood as non - limiting illustrative examples. Unless otherwise indicated, the drawings are not to scale, and any side of the drawing is shown as being to scale, and the scales shown are to be understood as non - limiting illustrative examples

[0010]

Figure 1

Figure 2

[0011]

Figure 3

[0012]

Figure 4

[0013]

Figure 5

[0014]

Figure 6

[0015]

Figure 7

Figure 8

Figure 9

Figure 10

DETAILED DESCRIPTION OF THE INVENTION

[0016] (Detailed Description) Referring to FIGS. 1 and 2, respectively, there is shown a front cross-sectional view and a side cross-sectional view of an exemplary radio frequency (RF) aperture including an interface printed circuit board (i-PCB) 10 having a front side 12 and a back side 14, and an array of conductive tapered protrusions 20 having a base 22 disposed on the front side 12 of the i-PCB 10 and extending away from the front side 12 of the i-PCB 10. The exemplary i-PCB 10 is shown in FIG. 1 as having dimensions of 5 inches × 5 inches, which is merely a non-limiting exemplary embodiment of a small RF aperture. FIG. 1 shows a front view of the RF aperture with an inset in the upper left showing a perspective view of one of the conductive tapered protrusions 20. This exemplary embodiment of the conductive tapered protrusion 20 has a square cross-section with a larger square base 22 and a vertex that does not extend to a complete tip but rather terminates at a flat vertex 24 (in other words, the conductive tapered protrusion 20 in the inset has a frustum of a cone shape). This is merely an exemplary embodiment, and more generally, the conductive tapered protrusion 20 can have any type of cross-section (e.g., square as in the inset, or circular, or hexagonal, or octagonal, etc.). The vertex 24 can be flat as in the embodiment of the inset, or can reach a sharp point, or be rounded, or have some other vertex geometry. The rate of tapering as a function of height (i.e., the distance "above" the base 22 in the state where the vertex 24 is at the maximum "height") can be constant as in the embodiment of the inset, or the rate of tapering can be variable with height, for example, the rate of tapering can increase with increasing height to form a protrusion with a rounded top, or can decrease with increasing height to form a protrusion with a more pointed tip. Similarly, as most detailed in FIG. 1, the exemplary array of conductive tapered protrusions 20 is a linear array with regular rows and orthogonal regular columns, however, the array may have other symmetries, such as hexagonal symmetry, octagonal symmetry, etc.In an illustrative embodiment of the insertion figure, the square base 22 and the square apex 24 lead to a conductive tapered protrusion 20 having four flat, inclined sidewalls 26. However, other sidewall shapes are also conceivable. For example, if the base as well as the apex is circular (or the base is circular and the apex reaches a point), the sidewalls will be inclined or tapered cylinders, and for a hexagonal base and a hexagonal apex or a pointed apex, there will be six inclined sidewalls, etc.

[0017] Continuing to refer to FIGS. 1 and 2 and further referring to FIG. 3, the RF aperture further includes, in an illustrative embodiment, a chip balun 30 mounted on the back side 14 of the i-PCB 10, and comprises an RF circuit network. Each chip balun 30 is electrically connected to two adjacent conductive tapered protrusions of the array of conductive tapered protrusions via an electrical feed-through 32 passing through the i-PCB 10, and has a balanced port P B (see FIGS. 3 and 6). Each chip balun 30 further has an unbalanced port P U for connection to the remainder of the RF circuit network (see FIGS. 3 and 6). The illustrative RF circuit network further includes an RF power splitter / combiner 40 for combining the outputs from the unbalanced ports P U of the chip baluns 30. As seen in FIG. 3, the illustrative electrical configuration of the RF circuit network employs a first-level 1×2 RF power splitter / combiner 401 for combining a pair of unbalanced ports P U and a second-level 1×2 RF power splitter / combiner 402 for combining the outputs of the pair of first-level RF power splitters / combiners 401. This is only an illustrative approach, and other configurations using, for example, 1×3 (combining three lines), 1×4 (combining four lines), or higher combining RF power splitters / combiners, or various combinations thereof, etc., are also conceivable. The illustrative RF circuit network further includes, for each unbalanced port P UIt includes a signal conditioning circuit 42 that is inserted between the non-balanced port and the first-level 1×2 power splitter 401. The signal conditioning circuit 42 connected to each non-balanced port includes an RF transmission amplifier T, an RF reception amplifier R, and an RF switching circuit network including a switch RFS configured to switch between a transmission mode that operably connects the RF transmission amplifier T and the non-balanced port and a reception mode that operably connects the RF reception amplifier R and the non-balanced port.

[0018] Continuing to refer to FIGS. 1-3 and further referring to FIGS. 4 and 5, a compact design (e.g., 3-inch depth in the non-limiting illustrative embodiment of FIG. 3) is achieved by employing one or more printed circuit boards (PCBs) that include at least the i-PCB 10, in part. In the illustrative embodiment shown in FIG. 3, the chip balun 30 is mounted on the back side 14 of the i-PCB 10. Optionally, other electronic components may also be mounted on the back side of the i-PCB 10 where an array of conductive tapered protrusions 20 is disposed on its front side 12. However, there may be insufficient footprint on the i-PCB 10 to mount all of the electronics of the RF circuitry. In the illustrative embodiment, this is addressed by providing a second printed circuit board 50 that is disposed in parallel with the i-PCB 10 and faces the back side 14 of the i-PCB 10. In other words, the second printed circuit board 50 is disposed on the (back) side 14 of the i-PCB 10 opposite the (front) side 12 of the i-PCB 10 where the conductive tapered protrusions 20 are disposed. The RF circuitry comprises electronic components that are mounted on a second printed circuit board 50, which may also be referred to herein as a signal conditioning PCB or SC-PCB 50, and additionally or alternatively, comprises electronic components that are mounted on the i-PCB 10 (typically on the back side 14 of the i-PCB, although it is also contemplated to mount components of the RF circuitry on the front side of the i-PCB within the field space between the conductive tapered protrusions 20 (not shown)). When the SC-PCB 50 is provided, as shown in FIG. 2, it is properly secured parallel to the i-PCB 10 by standoffs 54 and a single-ended feedthrough 52 is provided to electrically interconnect the i-PCB 10 and the SC-PCB 50 (see FIG. 3). If the RF circuitry cannot fit within the footprint of the two PCBs 10, 50, a third (and optionally a fourth, and additional) PCB may be added to accommodate the components of the RF circuitry (not shown).

[0019] Figure 4 shows a front view of the i-PCB 10, including vias and mounting holes, and schematically shows the locations of the baluns 30 and register pads as shown within the legend shown in Figure 4. (The register is used to terminate the unused side of the pyramid to help reduce the radar cross-section.)

[0020] Referring to FIG. 2 and further to FIG. 5, an exemplary RF aperture has an enclosure 58 that, in the exemplary embodiment, is affixed around the periphery of the i-PCB 10 in a state where the periphery of the i-PCB 10 encloses an RF circuit network. This is merely one exemplary arrangement and other designs are conceivable. For example, both PCBs 10, 50 may be disposed inside the enclosure (provided that such an enclosure should not have an RF shield extending forward to block the area of the RF aperture). FIG. 5 schematically shows an RF connector (or port) 60 (also shown or depicted in FIGS. 2 and 3), control electronics 62 (e.g., an exemplary phased array beam steering electronics 63 shown as a non-limiting figure, and these electronics 62, 63 may be mounted outside the enclosure 58 and / or disposed inside the enclosure 58 to provide a beneficial RF shield), and a power connector 64 for providing power (e.g., operating power for an active RF transmission amplifier T, an active RF reception amplifier R, and a switch RFS) to operate the active components of the RF circuit network. A rear view of the enclosure 58 of the RF aperture is schematically illustrated showing the various components 60, 62, 63, 64 over the area on the back side of the enclosure. The specific arrangement of the various components 60, 62, 63, 64 over the area on the back side of the enclosure can vary widely from that shown in FIG. 5, and these components may be located elsewhere. For example, the RF connector 60 may alternatively be located at the edge of the RF aperture and so on. It should also be understood that the RF aperture may be integrally constructed with some other component or system. For example, when the RF aperture is used as an RF transmission element and / or a reception element of a mobile base station, marine radio, unmanned aerial vehicle (UAV), etc., the enclosure 58 can be replaced by having an RF aperture built into the housing of a mobile base station, marine radio, UAV airframe, etc. In such a case, the RF connector 60 can also be replaced by a wired connection to a mobile base station, marine radio, UAV electronics, etc.

[0021] Referring specifically to FIG. 3, an illustrative electrical configuration for an illustrative RF circuitry is shown. In this non-limiting illustrative example, it is assumed that the array of conductive tapered protrusions 20 is a 5×5 array of conductive tapered protrusions 20, as shown in FIGS. 1 and 4. The balanced port P of the chip balun 30 B(in the receiving mode or, alternatively, in the transmitting mode so as to apply a differential RF signal between two adjacent conductive tapered protrusions 20), connect adjacent (i.e., neighboring) pairs of the conductive tapered protrusions 20 of the array so as to receive a differential RF signal between the two adjacent conductive tapered protrusions 20. As detailed in Steinbrecher U.S. Patent No. 7,420,522, which is hereby incorporated by reference in its entirety, the tapering of the conductive tapered protrusions 20 presents a separation between two conductive tapered protrusions 20 that varies with the "height", i.e., with the distance "above" the base 22 of the conductive tapered protrusion 20. Since a range of RF wavelengths corresponding to the range of separation introduced by the tapering between adjacent conductive tapered protrusions 20 can be captured, this provides broadband RF capture. The RF aperture is thus a differential segmentation aperture (DSA) and has differential RF receiving (or RF transmitting) elements corresponding to adjacent pairs of the conductive tapered protrusions 20. These differential RF receiving (or transmitting) elements are referred to herein as aperture pixels. For an exemplary linear 5×5 array of adjacent conductive tapered protrusions 20, this means that there are four aperture pixels along each row (or column) of the five conductive tapered protrusions 20. More generally, for a linear array of protrusions having a row (or column) of N conductive tapered protrusions 20, there will be a corresponding N - 1 pixels along the row (or column). FIG. 3 shows a QUAD subassembly that is an interconnection of a row (or column) of four pixels. Since there are four rows and four columns, this leads to 4×4 or 16 such QUAD subassemblies. Register pads are used as terminations for the unused edges of the surrounding pyramids to prevent unwanted reflections. Without the registers mounted via the register pads, their surfaces would remain floating and re-radiate the incident RF energy, causing an enhanced radar cross-section.

[0022] In the illustrative embodiment shown in FIG. 3, the second-level 1×2 RF power divider / combiner 402 of each QUAD subassembly is connected to the RF connector 60 on the back side of the enclosure 58. Thus, as seen in FIG. 5, there are eight RF connectors for the eight QUAD subassemblies shown in FIGS. 4 and 5, such as row QUAD subassemblies N1, N2, N3, N4 and column QUAD subassemblies M1, M2, M3, M4. The Gnd(N) row and Gnd(M) column are circuit grounds to enable a common path for current flow from the captured RF energy along the perimeter side of the pyramid. The use of QUAD subassemblies allows a high level of flexibility in RF coupling to the RF aperture. For example, an exemplary phased array beam steering electronics 63 has appropriate phase offsets for the row QUAD subassemblies N1, N2, N3, N4

Number

Number

[0023] The described electronic device that employs the PCBs 10, 50, the chip balun 30, and the active signal conditioning components (e.g., the active transmission amplifier T and the reception amplifier R) advantageously enables the RF aperture to be made small and lightweight. As will be described next, the embodiment of the conductive tapered protrusion 20 further facilitates providing a small and lightweight broadband RF aperture.

[0024] FIG. 6 shows a side cross-sectional view of one illustrative embodiment in which each conductive tapered protrusion 20 is processed as a dielectric tapered protrusion 70 with a conductive layer 72 disposed on the surface of the dielectric tapered protrusion 70. The dielectric tapered protrusion may be made of an electrically insulating plastic or ceramic material such as acrylonitrile butadiene styrene (ABS), polycarbonate, etc., and may be manufactured by injection molding, three-dimensional (3D) printing, or other suitable techniques. The conductive layer 72 may be any suitable conductive material such as copper, copper alloy, silver, silver alloy, gold, gold alloy, aluminum, aluminum alloy, etc., or may include a layered stack of different conductive materials, and may be coated on the dielectric tapered protrusion 70 by vacuum evaporation, RF sputtering, or any other vacuum deposition technique. FIG. 6 shows an example in which solder points 74 are used to electrically connect the conductive layer 72 of each dielectric tapered protrusion 20 to its corresponding electrical feed-through 32 passing through the i-PCB 10. FIG. 6 also shows an exemplary connection of one chip balun 30 between two adjacent conductive tapered protrusions 20 via a solder point 76 at the equilibrium port P B of FIG.

[0025] Figures 7 and 8 respectively show an exploded side cross-sectional view and a perspective view of an embodiment in which a dielectric tapered protrusion 70 is integrally included in a dielectric plate 80. A conductive layer 72 coats each dielectric tapered protrusion 70, but has an insulating gap 82 that provides galvanic insulation between adjacent dielectric tapered protrusions 20. The insulating gap 82 can be formed after coating the conductive layer 72 by etching the coating away from the plate 80 between the conductive tapered protrusions 20 to insulate the conductive tapered protrusions from each other DC-wise. Alternatively, the insulating gap 82 can be defined prior to coating by depositing a mask material (not shown) on the plate 80 between the conductive tapered protrusions 20 such that the coating does not coat the plate within the insulating gap 82 between the conductive tapered protrusions, thereby insulating the conductive tapered protrusions from each other DC-wise. As seen in the perspective view of FIG. 8, as a result, the dielectric plate 80 covers (and thus closes) the surface of the i-PCB 10 with the conductive tapered protrusions 20 extending away from the dielectric plate 80.

[0026] Referring particularly to FIG. 7, in one approach for electrical interconnection, through holes 82 pass through the exemplary plate 80 and underlying i-PCB 10, and rivets, screws, or other conductive fasteners 32' pass through the through holes 82 (note that FIG. 7 is an exploded view), and thus, when disposed, form electrical feed-throughs 32' that pass through the i-PCB 10. (Note that the perspective view of FIG. 8 is simplified and does not depict the fasteners 32'.) The use of the dielectric plate 80 with the integral dielectric tapered protrusions 70 and the combined fastener / feed-through 32' advantageously allows the conductive tapered protrusions 20 to be disposed without soldering using precise positioning.

[0027] In the embodiment of FIGS. 6 - 8, the conductive coating 72 is disposed on the outer surface of the dielectric tapered protrusion 70. In this case, the dielectric tapered protrusion 70 may be either hollow or solid.

[0028] Referring to FIGS. 9 and 10, since the dielectric material is substantially transparent to RF radiation, the conductive coating 72 may instead be coated on the inner surface of the (hollow) dielectric tapered protrusion 70. FIG. 9 shows a side cross - sectional view of such an embodiment, while FIG. 10 shows a perspective view. The embodiments of FIGS. 9 and 10 again employ a dielectric plate 80 including a dielectric tapered protrusion 70. As seen in FIG. 10, by coating the inner surface of the hollow dielectric tapered protrusion 70 with the conductive coating 72, this protects the conductive coating 72 from external contact by the dielectric plate 80 including the integral dielectric tapered protrusion 70. This may be useful in environments where weather can be a problem.

[0029] It should be understood that the various disclosed aspects are illustrative examples, and that the disclosed features may, in specific embodiments, be variously combined or omitted. For example, one or variants of the illustrative examples of the conductive tapered protrusion 20 may be employed without the QUAD sub - assembly circuit network configuration of FIGS. 2 - 5. Conversely, the QUAD sub - assembly circuit network configuration of FIGS. 2 - 5 or their variants may be employed without the dielectric / coating configuration for the conductive tapered protrusion 20. Similarly, the chip balun 30 may or may not be used in specific embodiments and the like.

[0030] Preferred embodiments have been illustrated and described. Obviously, modifications and variations will occur to those skilled in the art upon reading and understanding the foregoing detailed description. It is intended that the invention be construed to include all such modifications and variations as fall within the scope of the appended claims or their equivalents.

Claims

**Claim 1** A radio frequency (RF) aperture, comprising: an interface printed circuit board having a front side and a back side; a linear array of conductive tapered protrusions, each conductive tapered protrusion having a base disposed on the front side of the interface printed circuit board and extending from the front side of the interface printed circuit board to a vertex; a balun mounted on the back side of the interface printed circuit board, each balun having an equilibrium port electrically connected to two adjacent conductive tapered protrusions through an electrical feed-through passing through the interface printed circuit board so as to receive or apply a differential RF signal between the two adjacent conductive tapered protrusions, and each balun further having a non-equilibrium port; an RF circuit network disposed on the back side of the interface printed circuit board and electrically connected to the non-equilibrium port of the balun The RF aperture. **Claim 2** The RF aperture according to claim 1, wherein the balun comprises a chip balun, and the RF circuit network comprises electronic components mounted on the back side of the interface printed circuit board. **Claim 3** The RF aperture according to any one of claims 1-2, further comprising a second printed circuit board disposed parallel to the interface printed circuit board and facing the back side of the interface printed circuit board; wherein the RF circuit network comprises electronic components mounted on the second printed circuit board. **Claim 4** The RF aperture according to any one of claims 1-3, wherein the RF circuit network comprises an RF power splitter / combiner connecting one or more combinations of the non-equilibrium ports of the balun to one or more RF connectors. **Claim 5** The RF aperture according to claim 4, wherein the RF power splitter / combiner is interconnected as a plurality of RF sub-assemblies, each RF sub-assembly connecting a subset of four or more of the non-equilibrium ports of the balun to a single RF connector. **Claim 6** The RF circuit network further comprises a plurality of analog / digital (A / D) converters. The RF power splitter / combiner is interconnected as a plurality of RF sub-assemblies, and each RF sub-assembly connects four or more subsets of the unbalanced ports of the balun to a single analog / digital (A / D) converter. The RF aperture according to claim 4.

7. The RF circuit network includes a signal conditioning circuit connected to each unbalanced port of the balun, and the signal conditioning circuit connected to each unbalanced port is an RF transmission amplifier, an RF reception amplifier, and an RF switching circuit network configured to switch between a transmission mode that operably connects the RF transmission amplifier to the unbalanced port and a reception mode that operably connects the RF reception amplifier to the unbalanced port. The RF aperture according to any one of claims 1-6.

8. The linear array of the conductive tapered protrusions is a dielectric tapered protrusion, and a conductive layer disposed on the surface of the dielectric tapered protrusion. The RF aperture according to any one of claims 1-7.

9. The RF aperture according to claim 8, comprising a dielectric plate including the dielectric tapered protrusion.

10. The dielectric tapered protrusion is hollow, and the conductive layer is disposed on an outer surface or an inner surface of the hollow dielectric tapered protrusion. The RF aperture according to any one of claims 8-9.

11. A method of manufacturing a radio frequency (RF) aperture, comprising: coating the surface of a dielectric tapered protrusion with a conductive layer to form a conductive tapered protrusion; mounting the conductive tapered protrusion on the front side of an interface printed circuit board, each conductive tapered protrusion having a base disposed on the front side of the interface printed circuit board and extending from the front side of the interface printed circuit board to a vertex; mounting an RF circuit network on the interface printed circuit board and / or a second printed circuit board mounted in parallel with the interface printed circuit board; electrically connecting the RF circuit network to the conductive tapered protrusion so as to receive or apply a differential RF signal between adjacent pairs of the conductive tapered protrusions. A method.

12. The dielectric tapered protrusion is integral with the surface of the dielectric plate and extends away from the surface of the dielectric plate. The coating includes coating the dielectric plate including at least the integral dielectric tapered protrusion. The method further includes after the coating, etching the coating away from the dielectric plate between the conductive tapered protrusions to electrically insulate the conductive tapered protrusions from each other, or before the coating, depositing a mask material on the dielectric plate between the conductive tapered protrusions such that the coating does not coat the dielectric plate between the conductive tapered protrusions, thereby electrically insulating the conductive tapered protrusions from each other The method according to claim 11, including one of the above.

13. Mounting the RF circuit network includes mounting a balun on the back side of the interface printed circuit board, The electrically connecting includes electrically connecting each balanced port of the balun to two of the conductive tapered protrusions via an electrical feed-through passing through the interface printed circuit board. The method according to any one of claims 11-12.

14. A radio frequency (RF) aperture, An interface printed circuit board having a front side and a back side, A linear array of conductive tapered protrusions, each conductive tapered protrusion having a base disposed on the front side of the interface printed circuit board and extending from the front side of the interface printed circuit board to a vertex. The conductive tapered protrusion includes a dielectric tapered protrusion and a conductive layer disposed on the surface of the dielectric tapered protrusion. A linear array of conductive tapered protrusions, An RF circuit network disposed on the back side of the interface printed circuit board and electrically connected to the linear array of conductive tapered protrusions via an electrical feed-through passing through the interface printed circuit board to receive or apply a differential RF signal between adjacent pairs of the conductive tapered protrusions An RF aperture comprising.

15. An RF aperture according to claim 14, comprising a dielectric plate including the dielectric tapered protrusions, wherein the conductive layer is not a portion of the dielectric plate that coats between the dielectric tapered protrusions such that the dielectric tapered protrusions are DC-insulated from each other.

16. The RF aperture according to any one of claims 14-15, wherein the dielectric tapered protrusions are hollow.

17. The RF aperture according to any one of claims 14-16, wherein the RF circuit network comprises electronic components mounted on the back side of the interface printed circuit board.

18. Further comprising a second printed circuit board arranged in parallel with the interface printed circuit board and facing the back side of the interface printed circuit board, The RF aperture according to any one of claims 14-17, wherein the RF circuit network comprises electronic components mounted on the second printed circuit board.

19. The RF aperture according to any one of claims 14-18, wherein the RF circuit network includes a balun with a balanced port that connects pairs of adjacent conductive tapered protrusions within a linear array of the conductive tapered protrusions via the electrical feed-through passing through the interface printed circuit board.

20. The RF aperture according to claim 19, wherein the RF circuit network further includes a first-level RF power divider / combiner that connects the unbalanced ports of two baluns respectively.

21. The RF aperture according to claim 20, wherein the RF circuit network further includes a second-level RF power divider / combiner that connects two first-level RF power dividers / combiners respectively.

22. The RF circuit network further includes a signal conditioning circuit connected to the unbalanced port of each balun, and the signal conditioning circuit includes an RF transmission amplifier, an RF reception amplifier, and an RF switching circuit network configured to switch between a transmission mode in which the RF transmission amplifier is operably connected to the unbalanced port and a reception mode in which the RF reception amplifier is operably connected to the unbalanced port The RF aperture according to any one of claims 19-21.

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