System and method for a multiband concentric helical antenna

Abstract

To provide a system and method that allows more antennas to be present on a spacecraft while minimizing the platform volume used for antennas. [Solution] The multiband concentric helical antenna system 100 includes bases 115, 125, a first helical antenna 110, and at least a second helical antenna 120, wherein the second helical antenna is located within the first helical antenna, the first helical antenna has a first frequency band, and the second helical antenna has a second frequency band that is not the same as the first frequency band, and the first and second helical antennas are connected to the base and located within an opening in the base. The multiband helical antenna system may further include N additional antennas, which can be used as a single radiating element or in an array of radiating elements.

Description

Technical Field

[0001] The following generally relates to systems and methods for combining antennas, and more specifically helical antennas, within the same aperture.

Background Art

[0002] In the space industry, antennas are common components on spacecraft and are used for long - distance communication. Different antennas can have different frequency bands depending on their role. However, the available volume on a spacecraft platform to accommodate all the necessary antennas may be limited.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Therefore, there is a need for systems and methods that allow more antennas to be present on a spacecraft while minimizing the platform volume used for the antennas.

Means for Solving the Problems

[0004] A multi - band concentric helical antenna system is provided herein that includes a base, a first helical antenna, and at least a second helical antenna. The second helical antenna is within the first helical antenna. The first helical antenna has a first frequency band and the second helical antenna has a second frequency band that is different from the first frequency band. The first helical antenna and the second helical antenna are connected to the base and are disposed within the aperture of the base.

[0005] The antenna system can be on a spacecraft.

[0006] The first helical antenna and the second helical antenna can be used for navigation.

[0007] The first helical antenna and the second helical antenna can be radiating elements that together form a multiband radiating element.

[0008] The base may include a first cup, in which a first helical antenna is placed, and the first cup includes a first wall.

[0009] The base may include a second cup, the second helical antenna being placed inside the second cup, and the second cup including a second wall.

[0010] The first or second cup may contain chalk, and the outer wall surrounds the first wall.

[0011] The first helical antenna and the second helical antenna can be concentric.

[0012] The antenna system may further include N additional antennas, each of which is connected to a base and positioned within an opening in the base, and each of the N additional antennas having a distinct frequency band.

[0013] The first helical antenna and the second helical antenna can have the same spiral winding pattern.

[0014] The first helical antenna and the second helical antenna may have opposite spiral windings.

[0015] At least one of the first helical antenna and the second helical antenna can be tapered.

[0016] A multiband radiating element is provided herein, comprising a first helical antenna and at least a second helical antenna, wherein the second helical antenna is located within the first helical antenna, the first helical antenna has a first frequency band, the second helical antenna has a second frequency band which is not the same as the first frequency band, and the first and second helical antennas are connected to a base. An antenna array comprising a plurality of such radiating elements is also provided herein. The array may include at least one single-frequency radiating element.

[0017] A method for constructing a multiband helical antenna system is provided herein, the method comprising: connecting a first helical antenna having a first frequency band to a base having an aperture, the aperture being a region of the base below the antenna; and connecting a second helical antenna having a second frequency band different from the first frequency band to the base, the second antenna being within the aperture of the base and the first antenna being within the second antenna.

[0018] This method may further include the step of connecting N additional antennas, each of which is positioned within an opening in the base, and each of the N additional antennas having a distinct frequency band.

[0019] The multiband helical system may further include a first cup comprising enclosed walls which are substantially perpendicular to the base and substantially parallel to the direction of the transmitted or received signal, and this method may further include the first helical antenna being positioned within the opening of the first cup.

[0020] The multiband helical system may further include a second cup comprising enclosed walls that are substantially perpendicular to the base and substantially parallel to the direction of the transmitted or received signal, and this method may further include a second helical antenna being positioned within the opening of the second cup.

[0021] Upon consideration of the following description of some exemplary embodiments, other aspects and features will become apparent to those skilled in the art.

[0022] The drawings included herein are for the purpose of illustrating various examples of the articles, methods, and apparatuses of this specification.

Brief Description of the Drawings

[0023] [Figure 1A] FIG. 1A is a side perspective view of a multi-band helical antenna system including a first antenna and a second antenna concentrically attached to the same base according to one embodiment. [Figure 1B] FIG. 1B is an elevation perspective view of the multi-band helical antenna system of FIG. 1A according to one embodiment. [Figure 2] FIG. 1C is a photograph of a cup and a choke for use with a helical antenna according to one embodiment. [Figure 3] FIG. 2 is a flow diagram of a method of constructing a multi-band antenna system according to one embodiment.

Best Mode for Carrying Out the Invention

[0024] Various devices or processes are described below to provide an example of each claimed embodiment. None of the embodiments described below limit the claimed embodiments, and each claimed embodiment can cover a process or device different from those described below. The claimed embodiments are not limited to a device or process having all of the features of any one of the devices or processes described below, nor are they limited to features common to a plurality or all of the devices described below.

[0025] Furthermore, process steps, method steps, algorithms, etc. may be described in sequential order (in the description and / or in the claims), but such processes, methods, and algorithms can be configured to function in an alternative order. In other words, any order or sequence of steps that can be described does not necessarily indicate that the steps should be performed in that order. The process steps described herein can be executed in any practical order. Furthermore, some steps can be executed simultaneously.

[0026] When describing a single device or article herein, it will be readily appreciated that more than one device / article (regardless of whether they cooperate) can be used in place of the single device / article. Similarly, when describing more than one device or article herein (regardless of whether they cooperate), it will be readily appreciated that a single device / article can be used in place of the more than one device or article.

[0027] The following generally relates to antennas, and more specifically to systems and methods for combining multiple helical antennas within the same aperture.

[0028] As described above, antennas are almost a universal element on spacecraft such as artificial satellites. However, the platforms used for artificial satellites have become smaller, and the area of artificial satellites on which antennas can be mounted has decreased. Therefore, reducing the size of antennas is increasingly desired or required.

[0029] The multi-band antenna system of the present disclosure reduces the area of the spacecraft platform used by the antenna by concentrically arranging at least two helical antennas of different sizes within a single aperture and operating each antenna within a different frequency band.

[0030] Since the frequency is determined by the diameter of the antenna's helix, combining at least two helical antennas of different sizes and frequency bands within the same aperture makes it possible to create a smaller antenna than a single antenna covering a larger frequency band.

[0031] Helix antennas are often used on spacecraft for GPS / navigation functions, but they can also be used as radiating elements.

[0032] Referring now to Figures 1A and 1B, a multiband helical antenna system 100 according to one embodiment is shown herein. System 100 includes a first antenna 110 and a second antenna 120, which are concentrically mounted on the same base or ground. Each pair of the first and second antennas can be used as a single radiating element or as an array of radiating elements (i.e., multiple instances of a multiband concentric helical antenna corresponding to array elements in the array). System 100 can be used as a phased array antenna. The array of elements resides on a single spacecraft, but each instance of the radiating element can be mounted on the same base or ground, or each instance (or subset) of the radiating element can be mounted on different bases or grounds.

[0033] The multiband helical antenna system 100 includes a first antenna 110, a second antenna 120, a first antenna cup 115, and a second antenna cup 125. The cups 115 and 125 may be the same height or of different heights. Since the system 100 covers two frequency bands, a first frequency band by the first antenna 110 and a second frequency band by the second antenna 120, the antenna system 100 can also be called a dual-band helical antenna system.

[0034] In other embodiments, system 100 may include more than two antennas. Each additional antenna may have its own cup. Each additional antenna may have a different frequency band. In other words, each antenna in system 100 covers a different frequency band. Therefore, a larger number of antennas in system 100 allows the antenna system 100 to cover a larger overall frequency band.

[0035] The first antenna 110 is a tapered helical antenna, where the diameter of the helix decreases in the Z direction.

[0036] The second antenna 120 is a tapered helical antenna, where the diameter of the spiral decreases in the Z direction.

[0037] The tapering of the helix increases the frequency bandwidth of the antenna. Therefore, using a tapered helix increases the frequency bandwidth of the antenna system 100. In other embodiments, one or both of the first antenna or the second antenna may not be tapered.

[0038] The first antenna 110 is located within the second antenna 120. The helices of the first antenna 110 and the second antenna 120 are concentric. In other embodiments, the antennas can be slightly deviated from concentricity, but the performance of the antenna system will decrease as the distance from concentricity increases.

[0039] In one embodiment of an antenna system 100 having more than two helical antennas, each additional antenna is positioned among the other antennas such that all of the helical antennas are concentric (or very close to concentric).

[0040] The first antenna 110 and the second antenna 120 are located within the same aperture. The aperture is a larger area at the "bottom" of antennas 110 and 120 (i.e., at the widest part of the antennas).

[0041] Cup 115 is located inside the opening, and cup 125 is located outside the opening. Cup 115 is associated with the first antenna, and cup 125 is associated with the second antenna. Cups 115 and 125 enable the separation of the two antennas 110 and 120. This separation improves the helical return loss and reduces the background radiation of the antenna system 100. In other embodiments, the antenna system 100 may not include either cup.

[0042] The bases of the first antenna 110 and the second antenna 120 (i.e., the vertical parts of the antennas at the "bottoms") can be in any relative positions. For example, they may be placed close together as shown in Figures 1A and 1B, or on opposite sides of the antenna system 100. Opposite placement of the connections can optimize antenna isolation.

[0043] The helices of the first antenna 110 and the second antenna 120 are wound in the same direction (i.e., they have the same winding pattern). In other embodiments, the helices can be wound in different directions. Helices wound in opposite directions can support opposite polarization, which is not possible with a single helix antenna.

[0044] In some embodiments, system 100 may include a helical support for the helix. The support may include a support thread and a central support mounted on a base. The support thread is connected to the helix and to the central support mounted on the base. The helical support restricts the movement of the helix away from its nominal position.

[0045] In various embodiments, the helical shape, cup dimensions, and input position of the helix can be optimized based on the specific frequency of the helical antenna to increase performance.

[0046] Next, referring to Figure 2, a photograph is shown of a cup 230 equipped with a choke 235 for use in a helical antenna, according to one embodiment.

[0047] Figures 1A and 1B show an antenna system 100 with a base including two cups 115, 125, one cup associated with a first antenna 110 and the other cup associated with a second antenna 120. Figure 2 is a photograph of a nearly circular cup 230 (only a portion of the cup is shown) including a closed wall, and a second wall 235 around the cup 230. The second wall prevents current from flowing outside the choke. In one embodiment of the antenna system 100, a helical antenna is positioned within the opening of the cup 230. In a dual-band helical antenna system or a multi-band (more than two) helical antenna system like system 100, there is another cup inside the cup 230, which may or may not include a second choke. That is, the cup 230 and choke 235 shown in Figure 2 provide an example of a cup that can also be used with a helical antenna, but not a configuration that would be used in a dual-band helical antenna system as described herein. The two cups shown in Figures 1A and 1B represent the cup system that should be used in a dual-band antenna system.

[0048] The cup 230 and choke 235 in Figure 2 are not solid and have multiple (i.e., many) openings. The cup 230 and choke 235 can therefore be considered weight-reduced (by the openings that provide weight reduction). The openings allow the cup 230 and choke 235 to have less weight than if they were solid. Reducing weight by including holes in the cup / choke can be particularly beneficial for larger antennas where mass reduction is important. Generally, the weight-reducing holes are small enough that some wavelengths cannot pass through.

[0049] The cup 230 and choke 235 in Figure 2 are also not perfectly circular, with the panels meeting at an angle. In various embodiments of cups (or chokes as well) for a multiband antenna system such as System 100, the shape of the cup 230 (or choke 235 as well) can be circular, hexagonal, etc. The inner and outer walls can have the same or different shapes.

[0050] In other embodiments, the cup / choke system may include three W-shaped walls.

[0051] Referring now to Figure 3, a method 300 for constructing a multiband antenna system according to one embodiment is shown herein. The multiband antenna system includes two helical antennas. Using method 300, the system 100 shown in Figures 1A and 1B can be constructed.

[0052] In 302, a first antenna having a first frequency band is connected to a base having an aperture, the aperture being a region of the base below the antenna that is substantially perpendicular to the direction of the transmitting or receiving antenna signal.

[0053] In 304, a second antenna having a second frequency band different from the first frequency band is connected to the base, such that the second antenna is inside the opening of the base and the first antenna is inside the second antenna.

[0054] Due to the physical requirement that the diameter of the first antenna be smaller than the diameter of the second antenna, the first antenna has a higher frequency band than the second antenna.

[0055] The first antenna and the second antenna are preferably concentric.

[0056] The first antenna and the second antenna may have the same or opposite spiral winding patterns.

[0057] Either or both of the first and second antennas can be tapered.

[0058] In some embodiments, the first antenna is located within an opening in a first cup, which includes enclosed walls that are substantially perpendicular to the base and substantially parallel to the direction of the transmitted or received signal. The second antenna is located within an opening in a second cup, which also includes enclosed walls that are substantially perpendicular to the base and substantially parallel to the direction of the transmitted or received signal. In other embodiments, only one of the first and second antennas may be associated with the cup.

[0059] In other embodiments, the cup may further include an outer enclosed wall that allows the cup to function as chalk.

[0060] In another embodiment, method 300 further includes the step of adding N additional helical antennas to the antenna system, each helical antenna being connected to a base and each helical antenna having a separate frequency band.

[0061] While the above description provides examples of one or more devices, methods, or systems, it will be understood that other devices, methods, or systems may fall within the scope of the claims as interpreted by those skilled in the art. [Explanation of Symbols]

[0062] 100 Multiband Helical Antenna System 110 First antenna 115 First Antenna Cup 120 Second Antenna 125 Second Antenna Cup 230 cups 235 Chalk, the second wall

Claims

1. A multiband concentric helical antenna system, Bass and, A first helical antenna and at least a second helical antenna, A multiband concentric helical antenna system comprising: the second helical antenna being located within the first helical antenna; the first helical antenna having a first frequency band; the second helical antenna having a second frequency band not the same as the first frequency band; and the first and second helical antennas being connected to the base and positioned within an opening in the base.

2. The multiband concentric helical antenna system according to claim 1, wherein the multiband concentric helical antenna system is located on a spacecraft.

3. The multiband concentric helical antenna system according to claim 2, wherein the first helical antenna and the second helical antenna are used for navigation.

4. The multiband concentric helical antenna system according to claim 1, wherein the first helical antenna and the second helical antenna are radiating elements and together form a multiband radiating element.

5. The multiband concentric helical antenna system according to claim 1, wherein the base includes a first cup, the first helical antenna is disposed within the first cup, and the first cup includes a first wall.

6. The multiband concentric helical antenna system according to claim 1, wherein the base includes a second cup, the second helical antenna is disposed within the second cup, and the second cup includes a second wall.

7. The multiband concentric helical antenna system according to claim 5, wherein the cup includes a choke and the outer wall surrounds the first wall.

8. The multiband concentric helical antenna system according to claim 1, wherein the first helical antenna and the second helical antenna are concentric.

9. The multiband concentric helical antenna system according to claim 1, further comprising N additional antennas, each of which is connected to the base and positioned within the opening of the base, and each of which has a distinct frequency band.

10. The multiband concentric helical antenna system according to claim 1, wherein the first helical antenna and the second helical antenna have the same spiral winding pattern.

11. The multiband concentric helical antenna system according to claim 1, wherein the first helical antenna and the second helical antenna have opposite spiral winding directions.

12. The multiband concentric helical antenna system according to claim 1, wherein at least one of the first helical antenna and the second helical antenna is tapered.

13. A multiband radiating element comprising a first helical antenna and at least a second helical antenna, A multiband radiating element in which the second helical antenna is located within the first helical antenna, the first helical antenna has a first frequency band, the second helical antenna has a second frequency band which is not the same as the first frequency band, and the first and second helical antennas are connected to a base.

14. An antenna array comprising a plurality of multiband radiating elements as described in claim 13.

15. The antenna array according to claim 14, further comprising at least one single-frequency radiating element.

16. A method for constructing a multiband helical antenna system, A step of connecting a first helical antenna having a first frequency band to a base having an opening, wherein the opening is a region of the base below the first helical antenna, A step of connecting a second helical antenna having a second frequency band different from the first frequency band to the base, wherein the second helical antenna is located within the opening of the base and the first helical antenna is located within the second helical antenna, Methods that include...

17. The method according to claim 16, wherein the multiband helical antenna system further comprises N additional antennas, each of the N additional antennas being located within the opening of the base, and each of the N additional antennas having a distinct frequency band.

18. The multiband helical antenna system further includes a first cup comprising enclosed walls substantially perpendicular to the base and substantially parallel to the direction of the transmitted or received signal, wherein the first helical antenna is positioned within the opening of the first cup, according to claim 16.

19. The method according to claim 18, wherein the multiband helical antenna system further includes a second cup having enclosed walls substantially perpendicular to the base and substantially parallel to the direction of the transmitted or received signal, and the second helical antenna is positioned within the opening of the second cup.

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