2D phased array antenna panel with contoured edges

Abstract

A two-dimensional (2D) phased array antenna panel has contoured edges. When similar 2D phased array antenna panels are combined to form a 2D phased array antenna module, an antenna element positioned along each contoured edge of a given 2D antenna panel is separated by a first distance from a corresponding antenna element positioned along the contoured edge of an adjacent 2D antenna panel. This first distance is equal to the distance between adjacent antenna elements on the same 2D antenna panel.

Description

Technical Field

[0001] The present disclosure relates to a two-dimensional (2D) phased array radar. More specifically, the present disclosure relates, inter alia, to the shape and configuration of a 2D phased array antenna panel.

Background Art

[0002] Unlike mechanically operable parabolic radars, phased array radars use antenna modules that remain stationary. This module comprises a grid of fixed antenna elements, each of which is capable of transmitting and receiving signals. Also, unlike mechanically operable parabolic radars, phased array radars can generate multiple beams simultaneously and can electronically steer the beams much faster than mechanically operable parabolic radars. Therefore, phased array radars can more accurately control how, when, and where to direct a radar scan and can sense multiple objects simultaneously.

[0003] Phased array radars are often used to detect, identify, track, and catalog objects orbiting the Earth. It has been reported that there are over a million objects orbiting the Earth, some of which are classified as space debris. Many of these objects are less than 10 cm in diameter, if not most of them. In some cases, the cross-section of an object is as small as 1 - 2 cm. To detect, identify, track, and catalog orbiting objects that are smaller in size, the operating frequency of the phased array radar used for this purpose can be set to a relatively high frequency, such as a frequency in the S band (2 - 4 GHz).

[0004] Phased array radars used for the aforementioned purposes typically have a large grid of spaced-apart antenna elements on a 2D antenna substrate or panel, where multiple 2D antenna panels are arranged together to form a larger single 2D antenna module. Figures 1(a) and 1(b) illustrate a stereoscopic and top view, respectively, of a conventional 2D antenna module 100. In this example, the antenna module 100 comprises 48 2D antenna panels, such as 2D antenna panel 110.

[0005] Figures 1(a) and 1(b) show multiple antenna panels 110 constituting an antenna module 100, but these panels do not show the large number of antenna elements on each of the multiple antenna elements. However, Figure 2 illustrates several conventional adjacent antenna panels 210, which include an array of antenna elements 220 on top. As shown in the figure, the antenna elements can be arranged in a hexagonal configuration or pattern 230, which is also called a triangular grid, as opposed to a square grid. Among the essential importance for the function of a phased array radar is the distance between adjacent antenna elements.

[0006] The spacing between antenna elements affects gain as a secondary effect and the natural width of the primary beam at a distance from the radar. Within a certain range, decreasing the element spacing decreases array gain and increases the field of view without grating lobes. Increasing the element spacing increases array gain while decreasing the field of view without grating lobes. Grating lobes appear at an angle away from the primary beam and usually do not appear until a specific viewing angle is achieved. For example, a certain antenna element spacing D may not produce any grating lobes when the viewing angle is at target (e.g., 0°), but may produce grating lobes at useful or important viewing angles, such as viewing angles beyond 45° from target. Therefore, determining the antenna element spacing creates some trade-off between gain and field of view.

[0007] As an empirical rule, the field of view is maximized when the antenna element spacing is λ / 2, and this is a special case of the equation D = λ / (1 + sinθ), which gives the maximum antenna spacing to avoid grating lobes with a field of view of θ degrees. The symbol λ represents wavelength, and wavelength is inversely proportional to frequency. From this equation, it is clear that as frequency increases (i.e., wavelength decreases), D decreases. To capture smaller objects, the frequency can be higher, and therefore the distance D can be smaller. For a given wavelength, the smallest resolvable target is approximately λ / 5.

[0008] The distance between adjacent antenna elements decreases, but this is particularly relevant to the present disclosure if this distance is the same for all adjacent antenna elements across the entire 2D antenna module. This is true for adjacent antenna elements located on different but adjacent antenna panels, and therefore also for adjacent antenna elements located on the same antenna panel. However, in conventional phased array antenna module configurations, such as the phased array antenna module configuration illustrated in Figures 1 and 2, the flat edges of the antenna panels hinder this, especially when the number of antenna elements is large. More specifically, as illustrated in Figure 2, the distance d' between an antenna element located along the edge of one antenna panel and an antenna element located along the edge of an adjacent antenna panel is typically greater than the distance d between adjacent antenna elements located on the same antenna panel. This presents a problem.

[0009] As explained above, when the antenna element spacing d' is greater than the antenna element spacing d, the power level or gain associated with the main beam decreases, and the gain associated with the side lobes, such as the grating lobe, increases. The disadvantages are explained above. It is possible to mathematically compensate for the suboptimal side lobe structure using the "pattern synthesis" technique, which involves, among other things, applying weighting coefficients to these antenna elements. However, this process is complex, time-consuming, and can be expensive. [Overview of the project]

[0010] In light of the above description, a less complex and more effective solution is needed to address the problem associated with the distance d' between an antenna element located along the edge of one antenna panel and an antenna element located along the edge of an adjacent antenna panel, which is different from (for example, greater than) the distance d between adjacent antenna elements located on the same antenna panel.

[0011] As will be explained in more detail below, this disclosure addresses the aforementioned problem by providing a 2D antenna panel having contoured, i.e., nonlinear edges. For purposes of implementation and manufacturing, it will be understood that all edges of each antenna panel may be contoured, but in particular, contoured edges that border the edges of adjacent antenna panels. Contoured edges offer several advantages.

[0012] According to the exemplary embodiments described herein below, at least a first advantage associated with contoured edges is that an antenna element positioned along the edge of a given antenna panel is positioned relative to an antenna element positioned along the corresponding edge of an adjacent antenna panel, and as a result, the distance d' between each antenna element along the edge of a given antenna panel and the corresponding antenna element along the corresponding edge of an adjacent antenna panel is equal to the distance d between antenna elements located on the same antenna panel. This, in turn, mitigates the problems described above associated with distance d', which is a distance different from distance d.

[0013] According to the exemplary embodiments described herein, a second advantage is that the contoured edges provide sufficient space above the underside of the antenna panel and below each antenna element, particularly those located along the edges of the antenna panel, to accommodate the radio frequency (RF) circuitry associated with each antenna element. In conventional configurations, when the antenna element spacing d' is equal to the antenna element spacing d, the space above the underside of the antenna panel, more specifically the space below the antenna elements located along the edges of the antenna panel, is limited and therefore cannot accommodate all the necessary RF circuitry. Consequently, the RF circuitry may need to be located elsewhere and connected to the antenna elements on the antenna panel via cabling, which increases manufacturing costs and introduces noise, phase errors, and signal loss to the transmitted and received signals supplied to and received from the antenna elements. In contrast, according to the exemplary embodiments described herein, the RF circuitry associated with each antenna element on a given antenna panel may be located above the underside of the antenna panel, integrated within the underside of the antenna panel, and connected to the corresponding antenna element via a multilayer substrate design that does not require cabling. Thus, the exemplary embodiments described herein below also achieve higher performance by reducing manufacturing costs and minimizing the aforementioned noise and signal loss that occurs in conventional designs.

[0014] A first aspect of the present disclosure, according to exemplary and other embodiments, relates to a two-dimensional phased array radar module. The phased array radar module comprises a plurality of antenna panels. Each of the plurality of antenna panels comprises a plurality of antenna elements, wherein the first distance between each of the plurality of antenna elements on each of the plurality of antenna panels and all adjacent antenna elements on the same antenna panel is the same. Each of the plurality of antenna panels also comprises a contoured edge, which is configured to separate each antenna element along the first contoured edge of the plurality of antenna panels from the corresponding antenna element along the second adjacent edge of the plurality of antenna panels by a second distance, by positioning the first contoured edge of the plurality of antenna panels adjacent to a second contoured edge of the plurality of antenna panels, the second distance being equal to the first distance.

[0015] A second aspect of the present disclosure relates to a two-dimensional (2D) antenna panel configured, according to exemplary and other embodiments, to be combined with a plurality of similar 2D antenna panels to form a 2D phased array antenna module. The 2D antenna panel comprises a plurality of antenna elements, wherein the first distance between each of the plurality of antenna elements and all adjacent antenna elements is the same. The 2D antenna panel also comprises a plurality of contoured edges, which are configured to separate each antenna element along each of the plurality of contoured edges of the 2D antenna panel from a corresponding antenna element along another adjacent edge of the plurality of similar 2D antenna panels by a second distance, such that each of the plurality of contoured edges is positioned adjacent to another contoured edge of the plurality of similar 2D antenna panels, and the second distance is equal to the first distance. [Brief explanation of the drawing]

[0016] [Figure 1(a)]Figure 1(a) illustrates a three-dimensional and top view of an antenna module equipped with multiple conventional antenna panels. [Figure 1(b)] Figure 1(b) illustrates a three-dimensional and top view of an antenna module equipped with multiple conventional antenna panels.

[0017] [Figure 2] This illustrates the positioning of antenna elements on adjacent antenna panels in a conventional configuration.

[0018] [Figure 3(a)] Figure 3(a) illustrates stereoscopic, top, and enlarged views of an antenna module comprising a plurality of antenna panels and a plurality of antenna elements on each of the plurality of antenna panels, according to an exemplary embodiment described herein. [Figure 3(b)] Figure 3(b) illustrates stereoscopic, top, and enlarged views of an antenna module comprising a plurality of antenna panels and a plurality of antenna elements on each of the plurality of antenna panels, according to an exemplary embodiment described herein. [Figure 3(c)] Figure 3(c) illustrates stereoscopic, top, and enlarged views of an antenna module comprising a plurality of antenna panels and a plurality of antenna elements on each of the plurality of antenna panels, according to an exemplary embodiment described herein. [Figure 3(d)] Figure 3(d) illustrates stereoscopic, top, and enlarged views of an antenna module comprising a plurality of antenna panels and a plurality of antenna elements on each of the plurality of antenna panels, according to an exemplary embodiment described herein.

[0019] [Figure 4(a)] Figure 4(a) illustrates the positioning of antenna elements on adjacent antenna panels according to an exemplary embodiment described herein. [Figure 4(b)]FIG. 4(b) illustrates the positioning of antenna elements on adjacent antenna panels according to an exemplary embodiment described herein.

[0020] [Figure 5] An exemplary embodiment described herein schematically illustrates certain RF components located on the top and bottom surfaces of an antenna panel.

[0021] [Figure 6(a)] FIG. 6(a) illustrates a representative RF circuit integrated on the bottom surface of an antenna panel according to an exemplary embodiment described herein. [Figure 6(b)] FIG. 6(b) illustrates a representative RF circuit integrated on the bottom surface of an antenna panel according to an exemplary embodiment described herein.

[0022] [Figure 7] An exemplary embodiment described herein illustrates a representative multilayer substrate configuration for an antenna panel.

MODE FOR CARRYING OUT THE INVENTION

[0023] Generally, the present disclosure describes a two-dimensional (2D) phased array radar module, more specifically, a 2D antenna panel that constitutes the radar module. As will be understood by those skilled in the art of phased array radar, the configurations described herein are exemplary, other embodiments are possible, and within the intended scope of the present disclosure as described and claimed herein. Here, the present disclosure will be described in more detail with reference to the figures.

[0024] As used herein, various terms may mean direct or indirect, complete or partial, temporary or permanent acts or omissions. For example, when an element or component is referred to as "on," "connected to," or "coupled to" another element or component, that element or component may, with or without intervening elements or components, directly on, connected to, or coupled to other elements or components, including indirect or direct variations. In contrast, when an element or component is referred to as "directly connected" to another element or component, "directly coupled" to another element or component, or "directly connected" to another element or component, there are no intervening elements or components.

[0025] As used herein, various terms include various singular forms preceded by “a,” “an,” and “the,” which are intended to further include various plural forms unless the specific context explicitly indicates otherwise. Other terms such as “comprises,” “comprising,” “includes,” and “including,” and their variations, specify the presence of a particular feature, element, component, and the like, but do not exclude the presence or addition of one or more other features, elements, components, or the like.

[0026] When used herein, the term “or” is intended to mean inclusive “or” rather than exclusive “or.” That is, unless otherwise specified or evident from the context, “X uses A or B” is intended to mean any of the natural inclusive set of permutations. That is, when X uses A, when X uses B, or when X uses both A and B, “X uses A or B” is satisfied under any of the aforementioned cases.

[0027] Furthermore, relative terms such as “downward,” “lower,” “bottom,” “bottom,” “upward,” “up,” and “upper” may be used herein to describe the relationship of one element or component to another, particularly as presented in the accompanying set of illustrative drawings. However, such relative terms are intended to encompass different orientations and relative positions in addition to what is depicted and described. For example, if a component is described and illustrated as being on the “lower” surface of something such as an antenna panel, that component may also be described and illustrated as being on the “upper” surface when the antenna panel is turned upside down. Thus, as stated above, various relative terms, as well as others, may encompass different orientations and positions unless otherwise explicitly stated.

[0028] Terms such as “approximately” or “substantially” refer to possible variations from nominal values / terms as understood by those skilled in the art. Such variations are always included in any given value / term provided herein, regardless of whether such variations specifically refer to any given value / term.

[0029] Terms such as "first," "second," etc., may be used herein to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not necessarily be limited by such terms to, for example, a particular order or sequence. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, the first element, component, region, layer, or section considered below may be referred to as the second element, component, region, layer, or section without departing from the various teachings of this disclosure.

[0030] Features described in relation to a particular embodiment may be combined and sub-combined in various other embodiments and / or with various other embodiments. Furthermore, different aspects and / or elements of an embodiment may be further combined and sub-combined in a similar manner as disclosed herein. Moreover, some embodiments, individually and / or collectively, may constitute components of a larger system, and other procedures may override and / or modify their applications. In addition, many steps may be required before, after, and / or concurrently with an embodiment, as disclosed herein. It should be noted that any and / or all methods and / or processes may be carried out at least partially through at least one entity in any way, as disclosed herein.

[0031] Figures 3(a) and 3(b) illustrate stereoscopic and top views, respectively, of the upper side of the antenna module 300 and the upper side of the multiple antenna panels 310 comprising the antenna module 300, according to an exemplary embodiment described herein. As illustrated in this exemplary embodiment, the multiple antenna panels 310 comprising the antenna module 300 are configured as an 8x6 array of 48 antenna panels 310. However, those skilled in the art of phased array radar systems will understand that the subject matter of the invention described herein is not limited to antenna modules having this size or configuration.

[0032] Figure 3(c) is an illustrated upper view of several antenna panels 310. As shown in the figure, each of the antenna panels 310 comprises a plurality of antenna elements, for example, antenna elements 320. In this illustrative diagram, each antenna panel 310 comprises 64 antenna elements arranged in a hexagonal pattern, as shown by pattern 330 in Figure 3(b). The particular number of 64 antenna elements is illustrative, as is the hexagonal pattern, and the subject matter of the invention described herein is not limited to this particular number of antenna elements or this particular antenna element pattern on a given antenna panel.

[0033] As shown in Figures 3(a) to 3(d), each antenna element comprises a pair of feed points, for example, the antenna feed section 340 in Figure 3(d). In the exemplary embodiments described herein, the antenna elements are cross-polarized printed antenna elements, where one feed section may be identified as horizontally polarized and the other feed section may be identified as vertically polarized. The panels may also transmit in right-hand circular polarization or left-hand circular polarization. Furthermore, according to the exemplary embodiments described herein, each antenna element rotates such that the feed section pair of the antenna element has a different orientation compared to the feed sections of each adjacent antenna element. This is best illustrated in Figure 3(d), which shows seven antenna elements 320(a) to 320(g) arranged in the aforementioned hexagonal pattern. Using the x,y coordinate system illustrated in Figure 3(d), it can be seen that the feed section of antenna element 320(g), located at the center of the hexagonal pattern, is oriented in the -y direction. However, none of the feed points of the other antenna elements 320(a) to 320(h) are oriented in the -y direction; that is, the feed point of antenna element 320(a) is oriented in the +y direction, the feed point of antenna element 320(b) is oriented in the +x direction, the feed point of antenna element 320(c) is oriented in the -x direction, the feed point of antenna element 320(d) is oriented in the +y direction, the feed point of antenna element 320(e) is oriented in the +x direction, and the feed point of antenna element 320(f) is oriented in the -x direction. However, as stated, none of the feed points associated with antenna elements 320(a) to 320(f), like antenna element 320(g), are oriented in the -y direction. The specific orientations of the antenna elements relative to each other are illustrative, as in the example above, and the subject matter of the present invention described herein is not limited to this specific relative orientation of the antenna elements.

[0034] Of particular importance to the exemplary embodiments described herein are the contoured edges of the multiple antenna panels 310. These contoured edges are more readily visible in the enlarged illustrative view of Figure 3(c). For example, in Figure 3(c), antenna panel 310(n) has four contoured edges 350(a)–350(d). That is, the contoured edges 350(a)–350(d) are not linear compared to the edges of the multiple antenna panels 110 illustrated in Figures 1–2. In the exemplary embodiments of Figures 3(a)–3(d), the contoured edges have a "scalloped" appearance that is somewhat similar to a sinusoid. These nonlinear edges will not coincide precisely at the corners, and therefore embodiments can include variations in the contour at the corners to ensure a continuous ground plane. A continuous ground plane can be beneficial to individual antenna patterns, as it reduces the intensity of RF near sensitive electronic equipment below the antenna array in order to reflect it. Holes in the ground plane can create crosstalk or leakage between the antenna and electronic equipment, which will introduce noise into the signal. Therefore, it may be beneficial to minimize the size of any holes in the corners where panels are joined. Patch antennas also work better if there is a continuous ground sheet beneath them. Therefore, an additional benefit of some embodiments is to ensure a seamless connection between all panels by adjusting the corner configuration to ensure a continuous ground plane.

[0035] Other contours are conceivable and fall within the scope of several embodiments. That is, adding edges to any contoured antenna panel to achieve the intended benefits described in detail below would fall within the scope of several embodiments. Thus, contoured edges having a sawtooth or square-wavy appearance may fall within the scope of several embodiments. However, sinusoidal edges can make it easier to integrate electronic devices with the panel and to assemble the panel.

[0036] Contoured edges allow the edges around antenna elements to be arranged in a hexagonal or triangular pattern. This pattern is superior to a square grid pattern, for example, allowing for better performance of more accurate radar. Having contoured edges allows for panels that are roughly rectangular or square, whereas without contoured edges. Such arrangements simplify the manufacturing process and can allow for larger panels, which improves quality and reduces costs. Manufacturing panels in this shape is also simpler. A straight line bisecting the panel results in a suboptimal hexagonal or parallelogram shape configuration. A straight line can be drawn through the panel, but it results in a rhombic shape, which is not optimal. Therefore, contoured edges are important for maintaining a beneficial shape.

[0037] As summarized above, by contouring the edges as illustrated, antenna elements positioned along the edge of a given antenna panel, and antenna elements positioned along the corresponding edge of an adjacent antenna panel, can be positioned, for example, closer to each other, so that the distance d' between an antenna element on a given antenna panel and an antenna element on an adjacent antenna panel is equal to the distance d between adjacent antenna elements located on the same antenna panel. Figures 4(a) and 4(b) illustrate how this is achieved.

[0038] Figures 4(a) and 4(b) illustrate the positioning of antenna elements in adjacent antenna panels according to exemplary embodiments described herein. More specifically, Figure 4(a) illustrates four antenna panels 410(a), 410(b), 410(c), and 410(d). With respect to antenna panel 410(a), it comprises 64 antenna elements, including a plurality of antenna elements, for example, an antenna element 420(a) positioned along the contoured edge 450(a) of antenna panel 410(a). With respect to antenna panel 410(b), it comprises 64 antenna elements, including a plurality of antenna elements, for example, an antenna element 420(b) positioned along the contoured edge 450(b) of antenna panel 410(b). Referring to Figure 4(b), the contoured edges 450(a) of antenna panel 410(a) and 450(b) of antenna panel 410(b) are, for example, closer to each other, facilitating the positioning of antenna elements 420(a) and 420(b) relative to each other. As a result, the distance d' between an antenna element positioned along the edge 450(a) of antenna panel 410(a) and an antenna element positioned along the edge 450(b) of antenna panel 410(b) is equal to the distance d between adjacent antenna elements located on the same antenna panel. More specifically, the contoured edge 450(a) of antenna panel 410(a) and the contoured edge 450(b) of antenna panel 410(b) enable antenna element 420(a) to be positioned relative to antenna element 420(b), and as a result, the distance d' between antenna elements 420(a)1 and 420(b)1 is the same distance d between antenna element 420(a)1 and an adjacent antenna element on antenna panel 410(a), and also the same distance d between antenna element 420(b) and an adjacent antenna element on antenna panel 410(b).Similarly, the contoured edge 450(a) of antenna panel 410(a) and the contoured edge 450(b) of antenna panel 410(b) also allow antenna element 420(a)2 to be positioned relative to antenna element 420(b)2, and as a result the distance d' between antenna element 420(a)2 and 420(b)2 is such that antenna element 420(a)2 and antenna element 420(a) are on antenna panel 410(a). 2 It can be seen that the distance d' between each antenna element 420(a) and the corresponding one of the antenna elements 420(b) is the same distance d as the distance d between antenna element 420(b)2 and the antenna element adjacent to antenna element 420(b)2 on antenna panel 410(b). The same applies to the distance d' between each antenna element 420(a) and the corresponding one of the antenna elements 420(b) being the same distance d as the distance d between each antenna element 420(a) and the adjacent antenna element on antenna panel 410(a), and the distance d between each antenna element 420(b) and the adjacent antenna element on antenna panel 410(b).

[0039] The contoured edges described above offer several significant advantages over conventional configurations. The first advantage is that the distance d' between each antenna element along the edge of a given antenna panel and the corresponding antenna element along the edge of an adjacent antenna panel is directly related to the relative positioning of the antenna elements, such that the distance d' between each antenna element along the edge of an adjacent antenna panel is the same as the distance d between adjacent antenna elements on the same antenna panel. When distances d' and d are the same, as defined above, the received radar signal can be processed more quickly, more efficiently, and more accurately. In contrast, if distance d' is not equal to distance d, the power level or gain associated with the main beam and any side lobes will change. More specifically, if distance d' is greater than distance d, the power level or gain associated with the main beam will decrease, and the gain associated with any side lobes will increase. As a person skilled in the art will understand, reducing the power level or gain of the main beam can reduce the level of the received radar signal, making it more difficult to detect, identify, and track the intended object. Conversely, an increase in the power level of any generated side lobes can result in undesirable radar signals at certain desirable viewing angles. To correct the undesirable effects associated with d' and d, which are not at the same distance, it may be possible to compensate by using mathematically complex processing techniques, as mentioned above, which increases processing time, increases processing complexity, and leads to more inaccurate results. In other words, a consistent array shape results in better beamforming, and therefore a stronger received signal / higher SNR. Contoured edges, as described herein, eliminate or at least minimize the need to use such complex techniques.

[0040] The second advantage of the contoured edge described above concerns the ability to integrate the RF circuitry associated with each antenna element onto the underside of the multilayer antenna panel. As explained above, the need to detect, identify, and track smaller objects necessitates the use of radar signals with shorter wavelengths, which, based on the general formula D=λ / (1+sinθ), results in a decrease in the distance D between each antenna element on the antenna panel. As D decreases, i.e., as the distance between antenna elements decreases, and as more antenna elements are positioned on a given antenna panel, there is less available space on the antenna panel for the RF circuitry that needs to condition the transmit and receive signals. Naturally, moving some or all of the RF circuitry away from the antenna panel is one option, but this is not an ideal solution. Doing so would increase manufacturing costs and would inevitably result in signal strength loss and phase errors due to the fact that the transmit and receive signals must pass through the antenna elements via cable wiring. Therefore, the ability to accommodate the RF circuitry for all antenna elements on the antenna panel is a significant advantage.

[0041] Figure 5 illustrates, according to exemplary embodiments described herein, a representative antenna element among a plurality of antenna elements on a given antenna panel, an RF circuit associated with this antenna element, and a co-feeding network that distributes the transmitted signal and combines the received signals between each of the plurality of antenna elements, for example, 64 antenna elements. More specifically, Figure 5 shows the representative antenna element as a cross-polarized printed antenna element having an H (horizontal) feed section and a V (vertical) feed section. This representative antenna element, together with the other plurality of antenna elements, is understood to be located on the upper surface or above the antenna panel, with the antenna panel facing an upward orientation. Furthermore, as shown in Figure 5 and according to exemplary embodiments disclosed herein, the RF circuit associated with each antenna element includes, but is not limited to, an RF transmit (TX) circuit and an RF receive (RX) circuit. The RF TX and RX circuits are located below the antenna element, and the antenna element is integrated into the antenna panel, corresponding to the RF TX and RX circuits, and forming, for example, the lower surface or most of the lower layers of the antenna panel. The RF circuit also includes a 90-degree hybrid coupler, a power amplifier (PA) associated with the transmit signal phase shifter (TX phase shift), and a low-noise amplifier (LNA) associated with the receive signal phase shifter (RX phase shift).

[0042] In the example in Figure 5, the transmit signal input is represented as a single line from a software-defined radio (SDR). This SDR is a radio transceiver that enables full-duplex operation. It uses sampling techniques and analog-to-digital / digital-to-analog converters to digitize the analog RF signal and process it accordingly in the digital domain. In the exemplary embodiment, since there are 64 antenna elements on the antenna panel, the transmit input is fed to a 64-way transmit (TX) splitter to distribute the transmit signal to each of the 64 antenna elements. Similarly, the radar signals received from each of the 64 antenna elements are fed through a 64-way receive (RX) combiner, and the combined single output signal is then fed back to the SDR on a single line. The 64-way TX splitter and 64-way RX combiner in the exemplary embodiments described herein are also integrated into the antenna panel.

[0043] Figure 6(a) illustrates the underside of a given antenna panel 600 having an internally integrated RF circuit for each of 64 exemplary corresponding antenna elements (not shown). As described above and illustrated in Figure 6(b), the RF circuit includes a 90-degree hybrid coupler, e.g., a 90-degree hybrid coupler 610, an RF TX circuit, e.g., an RF TX circuit 620, and an RF RX circuit, e.g., an RF RX circuit 630. Each antenna element may optionally include a large earth coupler (not shown), e.g., a ring around the antenna element and the entire RF circuit for creating a substantial ground connection to improve signal quality. This ring around the element may include a substrate-penetrating fence via for shielding from one cell to the next, or from one cell to a shared power network.

[0044] It should be noted that the antenna panel 600 has a boundary 650. The purpose of the boundary is to create a continuous ground plane to shield the RF circuitry above the bottom surface of the antenna panel from RF radiation transmitted and received by antenna elements located on or above the top surface of the antenna panel. The boundary may include any material suitable for achieving this purpose. It may also be important for the operation of the antenna array that all ground planes have the same potential across the panels.

[0045] It may include a subframe for connecting various panels, and having panels machined into a roughly square or rectangular shape can simplify the subframe design and improve the ability to maintain a continuous earth plane. The subframe can allow the boundary 650 to be electrically coupled, thereby forming a continuous earth plane and shielding sensitive circuits.

[0046] It is important to reiterate that the contoured edges of the antenna panel allow for the integration of RF circuits for each antenna element and a shared-feed network into the antenna panel. This is especially true for RF circuits associated with antenna elements located along the edges of each antenna panel. As seen in Figures 6(a) and (b), the contoured edges provide the necessary space for the RF circuits, and as a result, the RF circuits in a preferred embodiment are integrated in a manner that aligns with the corresponding antenna elements on the antenna panel. In contrast, if the edges of antenna panel 600 are uncontoured, i.e., flat as illustrated by line L in Figure 6(a), and the edges of antenna panels adjacent to antenna panel 600 are uncontoured, it will be clear that the distance between each antenna element along the edge of one antenna panel and the corresponding one of the antenna elements along the edge of the adjacent antenna panel on line L is not equal to the distance between adjacent antenna elements on the same antenna panel. As explained above, these inequalities are undesirable.

[0047] Figure 7 illustrates a multilayer substrate configuration for mounting a plurality of antenna elements, RF circuits communicating with each of the plurality of antenna elements, and a co-feeding network to a single corresponding antenna panel, according to an exemplary embodiment described herein. More specifically, Figure 7 shows a multilayer printed circuit board assembly for integrating the antenna elements, associated RF circuits, and co-feeding network into a single integrated antenna panel. To the right of each layer in Figure 7 are examples of materials used to create the lamination. These include core materials and thicknesses, as well as bonding layers or prepreg layers. Combining electronic equipment on a single multilayer substrate can be useful in reducing cost and complexity of installation and repair. Other prior art methods involve separating the antenna from the electronic components, which can increase complexity and cost. Therefore, combining electronic equipment as illustrated in Figure 7 can reduce cost and complexity, which is an additional benefit over the prior art.

[0048] In the exemplary embodiment illustrated in Figure 7, there are a total of 11 layers. The first layer L11 in Figure 7 is the outer layer and incorporates antenna elements, which are identified in Figure 7 as patch antennas. According to this exemplary embodiment, the first layer L11 is a planar design using a low-loss and stable core material. The element pattern can be realized by etching copper. The remaining 10 layers are bonded to the antenna element layer L111. Inter-layer connections are achieved using plated via connections as needed. As described above, according to the exemplary embodiment described herein, no cabling is required between any antenna elements and the corresponding RF circuit. Again, as mentioned above, this reduces costs while reducing losses associated with antenna feeding connections.

[0049] As is clear from Figure 7, the ten layers bonded to the first layer or antenna element layer include the associated RF circuitry and co-feeding network. Thus, as shown in this exemplary embodiment, layer L5 includes an embedded stripline for the RX combiner. Layer L3 includes an embedded stripline for the TX splitter. Layer L1 includes RF circuitry such as a 90-degree hybrid coupler, a transmit amplifier and a receive amplifier, and phase rotation components, which have been illustrated and described above with reference to Figures 5, 6(a), and 6(b). Several ground (GND) layers exist between the aforementioned functional layers L2, L4, L6 and L10. There are also two layers L8 and L9 from which power is supplied to the substrate, i.e., the components on the antenna panel.

[0050] Layers L3 and L5 implement the shared power supply network. As described, these layers distribute the transmitted signal and combine the received signals with multiple antenna elements, i.e., all 64 antenna elements. This is achieved using impedance-matched stripline connections embedded between the alternating earth plane layers mentioned above. Integrating the shared power supply network in, within, and into the antenna panel provides substantial cost savings from a manufacturing standpoint. It also reduces design complexity compared to designs that combine antenna elements externally using separate 64-directional combiner / divider modules and associated coaxial cabling. Combining antenna elements using external cabling also threatens the phase stability of the system against temperature fluctuations and can therefore result in phase errors that affect beamforming and directing accuracy. External cabling can have other problems, including substantially increased costs, and PCB materials can suffer from phase problems with respect to temperature. While it is common to provide phase-matched cables, PCB tracking allows for length matching in contrast.

[0051] As stated, multilayer substrate designs for antenna panels are important for several reasons. They make the design feasible and keep the cost per element low enough to still achieve the best performance by eliminating the need for cabling from the antenna panel to functionally similar elements located outside the antenna panel. Furthermore, as wavelengths become smaller (i.e., frequencies become higher) and the distance between antenna elements becomes smaller, the design becomes more compact and enables configurations to λ / 2, as described above.

[0052] Any means or steps in the following various claims + various corresponding structures, materials, actions, and equivalents of functional elements are intended to include, in particular as claimed, any such structures, materials, actions for carrying out a function in combination with other claimed elements. Various embodiments have been selected and described so as to best illustrate the various principles of this disclosure and its various practical applications, and so that others skilled in the art can understand this disclosure for various embodiments with various modifications when suitable for a particular intended use.

[0053] The detailed explanation provided above, while presented for illustrative and explanatory purposes, is not intended to be exhaustive and / or limiting to the Disclosure in any of the various forms disclosed. Many modifications and variations in technique and structure will be apparent to those skilled in the art without departing from the scope and / or spirit of the Disclosure, as described in the various claims that follow. Such modifications and variations are therefore considered to be part of the Disclosure. The scope of the Disclosure is defined by the various claims, which include known and unpredictable equivalents at the time of filing of the Disclosure.

Claims

1. A two-dimensional (2D) phased array radar module having multiple antenna panels, wherein each of the multiple antenna panels is A plurality of antenna elements, wherein the first distance between each of the plurality of antenna elements on each of the plurality of antenna panels and all adjacent antenna elements on the same antenna panel is the same, A two-dimensional (2D) phased array radar module comprising: a contoured edge, wherein a first contoured edge of the plurality of antenna panels is adjacent to a second contoured edge of the plurality of antenna panels, such that each antenna element along the first contoured edge of the plurality of antenna panels is separated by a second distance from the corresponding antenna element along the second adjacent edge of the plurality of antenna panels, the second distance being equal to the first distance.

2. Each of the aforementioned plurality of antenna panels is The 2D module according to claim 1, further comprising a plurality of contoured edges, wherein each of the plurality of contoured edges of each of the plurality of antenna panels is adjacent to another contoured edge of the plurality of antenna panels, such that each antenna element along each of the plurality of contoured edges is separated by a third distance from a corresponding antenna element along the other adjacent contoured edge of the plurality of antenna panels, the third distance being equal to the first distance and the second distance.

3. The 2D module according to claim 1, wherein each of the contoured edges of the plurality of antenna panels is configured in the form of a sinusoidal wave.

4. Each of the aforementioned multiple antenna panels is configured as a multilayer printed circuit board. The 2D module according to claim 1, wherein the first outer layer of each of the plurality of antenna panels incorporates the plurality of antenna elements associated with the antenna panel.

5. The 2D module according to claim 4, wherein the radio frequency (RF) circuits associated with each of the plurality of antenna elements on each of the plurality of antenna panels are integrated within the multilayer substrate configuration of each antenna panel and are aligned with and communicate with the corresponding one of the plurality of antenna elements without any cable wiring between the radio frequency circuits.

6. The RF circuit includes a transmitting RF circuit, The 2D module according to claim 5, wherein the second layer of the multilayer substrate configuration of each of the plurality of antenna panels comprises the transmitting RF circuit.

7. The RF circuit includes a receiving RF circuit, The 2D module according to claim 6, wherein the third layer of the multilayer substrate configuration of each of the plurality of antenna panels comprises the receiving RF circuit.

8. The fourth layer of the multilayer substrate configuration of each of the plurality of antenna panels is equipped with a shared power supply network, and the shared power supply network of each of the plurality of antenna panels is configured to distribute an input signal to each of the plurality of antenna elements on the corresponding antenna panel via the transmitting RF circuit, and to receive a combined output signal from the plurality of antenna elements on the corresponding antenna panel via the receiving RF circuit. The 2D module according to claim 7, wherein the shared power supply network receives the input signal from a software-defined radio (SDR) and transmits the output signal to the software-defined radio.

9. The 2D module according to claim 1, wherein the plurality of antenna elements on each of the plurality of antenna panels are arranged in a hexagonal pattern.

10. A two-dimensional (2D) antenna panel configured to be combined with multiple similar 2D antenna panels to form a 2D phased array antenna module, A plurality of antenna elements, wherein the first distance between each of the plurality of antenna elements and all adjacent antenna elements is the same, A two-dimensional (2D) antenna panel comprising: a plurality of contoured edges, each of which is positioned adjacent to another contoured edge of the plurality of similar 2D antenna panels, such that each antenna element along each of the plurality of contoured edges of the 2D antenna panel is separated by a second distance from a corresponding antenna element along the other adjacent edge of the plurality of similar 2D antenna panels, wherein the second distance is equal to the first distance.

11. The 2D antenna panel according to claim 10, wherein the plurality of contoured edges of the 2D antenna panel are configured in the shape of a sinusoidal wave.

12. The aforementioned 2D antenna panel is configured as a multilayer printed circuit board. The 2D antenna panel according to claim 10, wherein the first outer layer of the 2D antenna panel incorporates the plurality of antenna elements inside.

13. The 2D antenna panel according to claim 12, wherein a radio frequency (RF) circuit associated with each of the plurality of antenna elements is integrated into the multilayer substrate configuration and is aligned with and communicates with a corresponding one of the plurality of antenna elements without any cable wiring between the radio frequency circuits.

14. The RF circuit for each of the plurality of antenna elements includes a transmitting circuit, The 2D module according to claim 13, wherein the second layer of the multilayer substrate configuration comprises the transmitting RF circuit.

15. The RF circuit for each of the plurality of antenna elements includes a receiving RF circuit, The 2D module according to claim 14, wherein the third layer of the multilayer substrate configuration of each of the plurality of antenna panels comprises the receiving RF circuit.

16. The fourth layer of the multilayer substrate configuration is equipped with a shared power supply network, which is configured to distribute an input signal to each of the plurality of antenna elements via the transmitting RF circuit and to receive a combined output signal from the plurality of antenna elements via the receiving RF circuit. The 2D module according to claim 15, wherein the shared power supply network receives the input signal from the software-defined radio (SDR) and transmits the output signal to the software-defined radio.

17. The 2D antenna panel according to claim 10, wherein the plurality of antenna elements are arranged in a hexagonal pattern.

18. A two-dimensional (2D) phased array antenna panel, A plurality of antenna elements, arranged in a grid that cannot be bisected by a straight line without passing through one or more of the plurality of antenna elements, A two-dimensional (2D) phased array antenna panel comprising one or more contoured edges, each contoured edge formed around an antenna element on the edge of the antenna panel and further configured to mate with one or more additional phased array antenna panels.

19. The antenna panel according to claim 18, wherein one or more contoured edges are configured to connect to earth and to the boundaries of adjacent panels.

20. The antenna panel according to claim 18, wherein the one or more contoured edges comprises one or more corners configured to minimize holes and form a continuous ground plane.

21. The antenna panel according to claim 18, further comprising a multilayer printed circuit board.

22. The multilayer printed circuit board, The antenna panel according to claim 21, comprising a 90° hybrid coupler, a phase rotation component, an RX combiner, and a TX splitter.

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