Reduction of ripples in element patterns of geodesic antennas

Abstract

The device for mitigating ripple in an element pattern includes an inner cone (110), an outer cone (105), at least one drive element (115), and at least one director (205). The outer cone is coupled to the inner cone. The at least one drive element is coupled to the outer cone and configured to generate at least one primary beam (155). The at least one director is coupled to the outer cone and configured to direct the at least one primary beam. The inner cone and the outer cone may be concentric. The at least one drive element may include multiple drive elements (115). The at least one director may include multiple directors (205). The number of directors is equal to the number of drive elements.

Description

[Technical field]

[0001]

[0001] This disclosure is directed generally to geodesic antennas. More specifically, this disclosure is directed to mitigating ripples in the element patterns of geodesic antennas. [Background technology]

[0002]

[0002] A geodesic antenna is an antenna in which the antenna elements contribute to the beam pattern at all angles in azimuth. However, one problem faced by geodesic antennas is the phase ripple resulting from energy circulating around the geodesic antenna cone, which causes non-constructive interference with the beam pattern. Summary of the Invention

[0003]

[0003] The present disclosure provides mitigation of ripples in the element patterns of geodesic antennas.

[0004] In a first embodiment, an apparatus for mitigating ripple includes an inner core, an outer core, at least one drive element, and at least one director. The outer cone is coupled to the inner cone. The at least one drive element is coupled to the outer cone and configured to produce at least one primary ray. The at least one director is coupled to the outer cone and configured to direct the at least one primary ray.

[0005]

[0005] In a second embodiment, an apparatus for mitigating ripple includes an inner core, a first outer core, a second outer core, at least one driving element, and at least one director. The first outer cone is coupled to the inner cone, and the second outer cone is coupled to the first inner cone. The at least one driving element is coupled to the second outer cone and configured to produce at least one primary light. The at least one director is coupled to the second outer cone and configured to direct the at least one primary light.

[0006]

[0006] In a third embodiment, the device for mitigating ripple includes an inner core, a first outer core, at least one first driving element, at least one first director, a second outer core, at least one second driving element, and at least one second director. The first outer cone is coupled to the inner cone. The at least one first driving element is coupled to the first outer cone and configured to produce at least one first primary ray. The at least one first director is coupled to the first outer cone and configured to direct the at least one first primary ray. The second outer cone is coupled to the first outer cone. The at least one second driving element is coupled to the second outer cone and configured to produce at least one second primary ray. The at least one second director is coupled to the second outer cone and configured to direct the at least one second primary ray.

[0007]

[0007] Other technical features will become readily apparent to those skilled in the art from the following drawings, description, and claims. [Brief description of the drawings]

[0008]

[0008] For a more complete understanding of the present disclosure and its features, reference is made to the following descriptions taken in conjunction with the accompanying drawings, in which: [Figure 1]

[0009] FIG. 1 illustrates an exemplary geodesic antenna according to the present disclosure. [Diagram 2]

[0010] FIG. 2 illustrates an exemplary outer cone of a geodesic antenna according to the present disclosure with a director to mitigate ripple. [Diagram 3]

[0011] FIG. 3 illustrates an exemplary cross-sectional view of the geodesic antenna of FIG. 1 according to the present disclosure. [Figure 4]

[0012] FIG. 4 illustrates an exemplary unwrapped outer cone according to the present disclosure of the geodesic antenna of FIG. 2 displayed in two dimensions. [Figure 5A]

[0013] 5A-5D show example beam and element patterns for geodesic antennas with and without a director according to the present disclosure. [Figure 5B] 5A-5D show exemplary beam and element patterns of geodesic antennas with and without a director according to the present disclosure. [Figure 5C] 5A-5D show exemplary beam and element patterns of geodesic antennas with and without a director according to the present disclosure. [Figure 5D] 5A-5D show exemplary beam and element patterns of geodesic antennas with and without a director according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009]

[0014] 1-5D described below, and the various embodiments used to illustrate the principles of the present invention in this patent application, are merely exemplary and should not be construed as limiting the scope of the invention. Those skilled in the art will understand that the principles of the present invention may be implemented in any type of suitably arranged device or system.

[0010]

[0015] Figures 1-4 illustrate an exemplary geodesic antenna 100 in accordance with the present disclosure. In particular, Figure 1 illustrates a side view of geodesic antenna 100, Figure 2 illustrates an isolated portion of geodesic antenna 100, Figure 3 illustrates a cross-sectional view of geodesic antenna 100 of Figure 1, and Figure 4 illustrates an unwrapped outer cone of geodesic antenna 100 of Figure 2. The embodiment of geodesic antenna 100 in Figures 1-4 is for illustrative purposes only, and geodesic antenna 100 may have any other suitable element pattern.

[0011]

[0016] As shown in FIGS. 1-4, the geodesic antenna 100 is formed using nested geodesic lens antennas (GLAs), referred to as "cones." In the exemplary embodiment of FIGS. 1-4, the geodesic antenna 100 includes an outer cone 105 and an inner cone 110. The outer cone 105 and the inner cone 110 are concentric and function as a parallel plate waveguide. Although more than two cones can be used in the geodesic antenna 100, the relationship between the outer cone 105 and the inner cone 110 is described for simplicity, and the relationship between the outer cone 105 and the inner cone 110 can be extended to more than two cones. For example, an additional outer cone can be concentric with the inner cone 110 and the outer cone 105 to function as a parallel plate waveguide.

[0012]

[0017] The outer cone 105 represents the base of the geodesic antenna 100. The outer cone 105 may be formed from any suitable conductive material, such as one or more metals. Additionally, the outer cone 105 may be formed by any suitable method, such as casting or injection molding. Additionally, the outer cone 105 may have any suitable size, shape, and dimensions. In this example, the outer cone 105 is formed as a hollow cylinder that is covered on one side, forming a base of the outer cone 105. On the outer periphery of the cylinder opposite the base is a flare portion 135 that projects radially from the central axis of the outer cone 105. The surface of the flare portion 135 is at a reflex angle (greater than 180°) from the inner surface 125 of the outer cone 105.

[0013]

[0018] The inner cone 110 is inserted into and bonded to the outer cone 105. The inner cone 110 may be formed from any suitable conductive material, such as one or more metals. The conductive material of the inner cone 110 may be the same or different than the conductive material of the outer cone 105. The inner cone 110 may be formed in any suitable manner, such as by casting or injection molding. The inner cone 110 may have any suitable size, shape, and dimensions. In this example, the inner cone 110 is formed as a hollow cylinder, in which the outer base of the inner cone 110 is bonded to the inner base of the outer cone 105, such that the inner cone 110 extends from the interior of the outer cone 105. It is noted that although the inner cone 110 and the outer cone 105 are both described as having the same shape (hollow cylinder), the shapes of the outer cone 105 and the inner cone 110 may differ.

[0014]

[0019] Depending on the implementation, the inner cone 110 may share a base with the outer cone 105, or the inner cone 110 may be covered on one side to form the base of the inner cone 110 (in which case the base of the inner cone 110 is directly or indirectly bonded to the base of the outer cone 105). When the inner cone 110 is bonded to the outer cone 105, an annulus is formed between the inner surface 125 of the outer cone 105 and the outer surface 130 of the inner cone 110. The length of the inner cone 110 may extend beyond the top edge of the outer cone 105. The outer circumference of the inner cone 110 opposite the base of the inner cone 110 has a flared portion 145 that projects radially from the central axis of the inner cone 110. The surface of the flared portion 145 is at an acute or obtuse angle 150 from the outer surface 130 of the inner cone 110.

[0015]

[0020] The outer cone 105 and the inner cone 110 form a geodesic parallel plate waveguide as a pair of conformal structures, such as a pair of conical sections. The inner cone 110 is joined within the outer cone 105 to form a parallel waveguide, which is formed between the inner surface 125 of the outer cone 105 and the outer surface 130 of the inner cone 110. The inner surface 125 of the outer cone 105 and the outer surface 130 of the inner cone 110 represent the opposing plates of the waveguide.

[0016]

[0021] The outer cone 105 includes a flare portion 135 that can extend at an obtuse angle 140 from the top of the inner surface 125 of the outer cone 105. The inner cone 110 includes a flare portion 145 that can extend at an acute or obtuse angle 150 from the top of the outer surface 130 of the inner cone 110. The flare portion 135 of the outer cone 105 and the flare portion 145 of the inner cone 110 can focus the resulting waveguide radiating element pattern. The configuration of the flare portions 135 and 145 allows for an omni-directional waveguide radiating element pattern.

[0017]

[0022] Each of the multiple driven elements 115 is connected to a transmitter or receiver, for example, by using a transmission line. When the driven element 115 is implemented in a transmitting geodesic antenna 100, the driven element 115 is driven by a radio frequency (RF) signal from the transmitter. When the driven element 115 is implemented in a receiving geodesic antenna 100, the driven element 115 converts the collected RF waves into a current that is fed to the receiver. Each of the driven elements 150 may represent a quarter wavelength feed probe or other feed probe.

[0018]

[0023] At least one driven element 115 can be configured to generate a primary ray 155. The primary ray 155 from the driven element 115 is roughly focused from the outer cone 105, but secondary rays 160 can be generated as a by-product of the primary ray 155 interacting with the outer surface 130 of the inner cone 110 and the inner surface 125 of the outer cone 105, and can also be generated based on the general dispersion of the beam. At least one driven element 115 can also function as a monopole and generate electromagnetic rays in the opposite direction towards the reflector 120.

[0019]

[0024] The reflector 120 reflects the electromagnetic radiation from the driven element 115, which increases the gain of the primary beam 155. The reflector 120 is located at the base of the interior of the outer cone 105, a quarter wavelength away from the driven element. The reflector 120 is electromagnetically coupled to the driven element 115. As shown in FIG. 4, the primary beam 155 from each driven element 115 contributes a pointing angle within the scan angle 165. The primary beams 155 generate an element pattern that is appropriate for a particular application of the geodesic antenna 100.

[0020]

[0025] If no type of correction is applied, secondary rays 160 (or geodesic electromagnetic rays) can wrap between the inner cone 130 and the outer cone 125 and interfere with both the primary rays 155 and other secondary rays 160, causing ripples in the element pattern. This ripple can cause ambiguity in the phase response of the antenna 100 and affect (among other things) beam steering or other operations. This ripple effect causes higher order side lobes when forming beams. It may be necessary or desirable to minimize secondary rays 160 because they wrap around the inner 130 and outer 125 cones and destructively interfere with the primary rays 155.

[0021]

[0026] The inner cone 130 and outer cone 125 can be designed with a scan angle 165 that affects the gain and size of the antenna 100. A smaller scan angle 165 provides more gain but may require a taller antenna. A larger scan angle 165 provides less gain but allows for a smaller, more compact antenna.

[0022]

[0027] 2 and 3, the geodesic antenna 100 includes multiple driven elements 115, multiple directors 205, and a reflector 120. The use of directors 205 in the geodesic antenna 100 reduces the secondary rays 160, which cause a ripple effect as previously described. Although a single outer cone 105 is shown here, the geodesic antenna 100 can include any number of outer cones 105, and each additional outer cone 105 can include additional driven elements 115, additional directors 205, and additional reflectors 120.

[0023]

[0028] The director 205 acts as a resonator to direct the primary 155 out of the geodesic antenna 100 and reduce the generation of the secondary 160. In steering the primary 155, the director 205 increases the gain of the beam and makes the beam sharper. The director 205 is a passive element that is not connected to the transmitter or receiver. The director 205 is also a parasitic element that is electromagnetically coupled to the corresponding driven element 115.

[0024]

[0029] In some embodiments, each director 205 may be a Yagi director element that reduces ripples in the gain and phase pattern of a single element. Each director 205 forms a natural element taper that reduces side lobes when forming a beam. Each director 205 may be formed from any suitable conductive material, such as one or more metals. Each director 205 may be formed in any suitable manner. Each director 205 may have any suitable size, shape, and dimensions. In some embodiments, each director 205 is formed in a rod shape. Each director 205 may typically be shorter in length than the corresponding driven element 115.

[0025]

[0030] The director 205 can be matched with the driven elements 115 to properly focus the primary rays 155 and reduce the secondary rays 160. The geodesic antenna 100 can be designed with a single director 205 for each driven element 115, or with multiple directors 205 for each driven element 115. When multiple directors 205 are used for each driven element 115 of the geodesic antenna 100, the spacing between the directors 205 can be different, such as between 1 / 10 and 4 / 10 of the wavelength of the beam. The gain increase due to the director 205 can be added for each additional director 205. The gain of the beam increases with each additional director 205, while the bandwidth of the beam narrows.

[0026]

[0031] Although Figures 1-4 illustrate an example geodesic antenna 100, various modifications may be made to Figures 1-4. For example, geodesic antenna 100 may have multiple outer cones 105, each with a driven element 115 and a director 205, and may be used in combination with any suitable number and types of components and systems.

[0027]

[0032] 5A-5D show exemplary beam patterns and element patterns for a geodesic antenna with and without a director according to the present disclosure. In particular, FIG. 5A shows a typical beam pattern 300 for a geodesic antenna, FIG. 5B shows a directional beam pattern 305 for a geodesic antenna 100, FIG. 5C shows element gain patterns 320 and 325, and FIG. 5D shows element cumulative phase patterns 335 and 340. The beam pattern embodiments of FIG. 5A-5D are for illustrative purposes only, and geodesic antenna 100 is capable of generating any suitable beam pattern.

[0028]

[0033] As shown in Figure 5A, a typical beam pattern 300 is generated from a geodesic antenna without any director 205. The typical beam pattern 300 includes a peak 310 and multiple side lobes 315. The peak 310 is the desired effect of a beam formed from the primary 155. The side lobes 315 are a sign of ripple or interference of the primary 160 with the secondary 160.

[0029]

[0034] As shown in FIG. 5B, a directional beam pattern 305 is generated from the geodesic antenna 100 of FIGS. 1-4. The directional beam pattern 305 includes a similar peak 310, but the side lobes 315 are much less prominent. The use of the director 205 significantly reduces the amplitude of the side lobes 315, as evidenced by the amplitude of the side lobes 315 being 0.73 dB for the normal beam pattern 300 and -1.6 dB for the directional beam pattern 305 in this example.

[0030]

[0035] As shown in Figure 5C, element gain patterns 320 and 325 are generated from a geodesic antenna. The directional element gain pattern 320 is generated from the geodesic antenna 100 of Figures 1-4. The directional element gain pattern 320 includes a flat gain 330 and a natural taper compared to a normal gain pattern. The flat gain 330 results in a more predictable response.

[0031]

[0036] As shown in FIG 5D, element accumulated phase patterns 335 and 340 are generated from a geodesic antenna. Directional element accumulated phase pattern 335 is generated from geodesic antenna 100 of FIGS 1-4. Directional element accumulated phase pattern 335 has a smoother phase response than regular element accumulated phase pattern 340, which results in a more predictable response. Regular element accumulated phase pattern 340 also includes flat regions 345 that create phase ambiguity, which results in a less predictable response.

[0032]

[0037] Although Figures 5A-5D show example beam patterns 300 and 305 and element patterns 320, 325, 335, and 340 for a geodesic antenna with and without a director 205, various modifications to Figures 5A-5D may be made. For example, the beam patterns 300 and 305 of Figures 5A and 5B may vary based on the design of the geodesic antenna.

[0033]

[0038] It may be helpful to provide definitions of certain words and phrases used throughout this patent application. The terms "including" and "comprising" and their derivatives mean inclusion without limitation. The term "or" is inclusive and means "and / or." The term "related to" and its derivatives can mean including, contained within, interconnected with, containing, contained within, connected to or with, coupled to or with, communicable with, cooperating with, interleaving, juxtaposing, adjacent to, bound to, having the nature of, having a relationship with, and the like. When used with a list of items, the phrase "at least one of" means that one or more different combinations of the listed items may be used and only one item in the list may be required. For example, "at least one of A, B, and C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, A and B and C.

[0034]

[0039] The description in this application should not be construed to imply that any particular element, step, or function is an essential or critical element that must be included in the scope of the claims. The scope of patented subject matter is defined solely by the allowed claims. Moreover, no claim will invoke 35 U.S.C. §112(f) for any of the appended claims or claim elements unless the precise words "means for" or "step for" are expressly used in a particular claim and are followed by a specific phrase identifying the function. Use of terms such as "mechanism," "module," "device," "unit," "component," "element," "member," "apparatus," "machine," "system," "processor," or "controller" in the claims is understood and intended to refer to structures known to those skilled in the art as further modified or improved by the features of the claims themselves, and is not intended to invoke 35 U.S.C. §112(f).

[0035]

[0040] While this disclosure describes certain embodiments and generally associated methods, modifications and permutations of these embodiments and methods will be apparent to those skilled in the art. Thus, the above description of exemplary embodiments does not define or constrain this disclosure. Other modifications, substitutions, and alterations are possible without departing from the spirit and scope of this disclosure, as defined by the following claims.

Claims

1. Inner Cone; an outer cone coupled to the inner cone, the inner cone being nested inside the outer cone; at least one driving element coupled to the outer cone and disposed inside the outer cone between the inner cone and the outer cone, the at least one driving element configured to generate at least one primary line; and at least one director coupled to the outer cone and disposed inside the outer cone between the inner cone and the outer cone, the at least one director configured to direct the at least one primary beam; An apparatus comprising:

2. 10. The apparatus of claim 1, wherein the inner cone and the outer cone are concentric.

3. 10. The apparatus of claim 1, wherein the at least one drive element comprises a plurality of drive elements.

4. 10. The apparatus of claim 1, wherein the at least one director comprises a plurality of directors.

5. 10. The apparatus of claim 1, wherein the number of directors is equal to the number of drive elements.

6. 10. The apparatus of claim 1, wherein one of the at least one director is configured to direct a primary beam for each of the at least one driven element.

7. 10. The apparatus of claim 1, wherein a plurality of directors are configured to direct a primary beam for each of the at least one driven element.

8. Inner Cone; a first outer cone coupled to the inner cone; a second outer cone coupled to the first outer cone, the inner cone nested inside the first outer cone and inside the second outer cone; at least one driving element coupled to the second outer cone and disposed inside the second outer cone between the first outer cone and the second outer cone, the at least one driving element configured to generate at least one primary line; and at least one director coupled to the second outer cone and disposed inside the second outer cone between the first outer cone and the second outer cone, the at least one director configured to direct the at least one primary light; An apparatus comprising:

9. 9. The apparatus of claim 8, wherein the first outer cone and the second outer cone are concentric.

10. 9. The apparatus of claim 8, wherein the at least one drive element comprises a plurality of drive elements.

11. 10. The apparatus of claim 8, wherein the at least one director comprises a plurality of directors.

12. 9. The apparatus of claim 8, wherein the number of directors is equal to the number of drive elements.

13. 9. The apparatus of claim 8, wherein one of the at least one director is configured to direct a primary beam for each of the at least one driven element.

14. 9. The apparatus of claim 8, wherein a plurality of directors are configured to direct a primary beam for each of the at least one driven element.

15. Inner Cone; a first outer cone coupled to the inner cone; at least one first driving element coupled to the first outer cone and disposed inside the first outer cone between the inner cone and the first outer cone, the at least one first driving element configured to generate at least one first primary line; at least one first director coupled to the first outer cone and disposed inside the first outer cone between the inner cone and the first outer cone, the at least one first director configured to direct the at least one first primary light; a second outer cone coupled to the first outer cone, the inner cone nested inside the first outer cone and inside the second outer cone; at least one second driving element coupled to the second outer cone and disposed inside the second outer cone between the first outer cone and the second outer cone, the at least one second driving element configured to generate at least one second primary line; and at least one second director coupled to the second outer cone and disposed inside the second outer cone between the first outer cone and the second outer cone, the at least one second director configured to direct the at least one second primary light; An apparatus comprising:

16. 16. The apparatus of claim 15, wherein the inner cone, the first outer cone, and the second outer cone are concentric.

17. 16. The device according to claim 15, the at least one first drive element includes a plurality of first drive elements; and The at least one second drive element includes a plurality of second drive elements.

18. 16. The device according to claim 15, the at least one first director includes a plurality of first directors; and The at least one second director comprises a plurality of second directors.

19. 16. The device according to claim 15, the number of first directors is equal to the number of first drive elements; and The number of second directors is equal to the number of second drive elements.

20. 16. The device according to claim 15, one of the at least one first director configured to direct a primary beam for each of the at least one first drive element; and wherein one of the at least one second director is configured to direct a primary beam for each of the at least one second drive element.

21. 16. The device according to claim 15, a plurality of first directors configured to direct a primary beam for each of the at least one first drive element; and A plurality of second directors are configured to direct a primary beam for each of the at least one second drive element.

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