Circularly polarized antenna element with sequential rotational feeding

Abstract

Aspects of the present disclosure relate to a sequentially rotationally fed circularly polarized antenna element including a circularly polarized antenna element and a feed network coupled to the circularly polarized antenna element. The feed network may sequentially rotate the radio frequency signal. The feed network includes a first delay line and a second delay line, wherein the first delay line and the second delay line are located in different layers stacked on each other.

Description

Technical Field

[0001] The disclosed technology relates to circularly polarized antennas. Background Art

[0002] An antenna can transmit and / or receive radio frequency (RF) signals that propagate through space as electromagnetic waves. A radio transmitter can supply a signal to the antenna, and the antenna can radiate energy from the signal in the form of radio waves. An antenna can receive RF signals. The received RF signals can be processed by a radio receiver. Antennas can be used in various wireless communication applications. Some antennas can be circularly polarized and radiate an electric field that rotates over time and space. Summary of the Invention

[0003] The innovations described in the claims have several aspects, none of which are solely responsible for their desirable attributes. Without limiting the scope of the claims, some of the prominent features of the present disclosure will now be briefly described.

[0004] One aspect of the present invention is an antenna device comprising a circularly polarized antenna element and a feed network configured to sequentially rotate a radio frequency signal. The circularly polarized antenna element includes a first pair of ports and a second pair of ports. The feed network includes a first delay line, a second delay line connected to the first pair of ports, and a third delay line connected to the second pair of ports. The second delay line and the first delay line, and the second delay line are located in different layers stacked on top of each other. An antenna ground is located between the first delay line and the second delay line and provides shielding therebetween. The first delay line is coupled between the second delay line and the third delay line.

[0005] The impedances of the first delay line, the second delay line, and the third delay line can provide unequal power distribution to compensate for losses in the branches of the feed network.

[0006] The circularly polarized antenna element can include a patch. The circularly polarized antenna element and the feed network can be monolithically integrated.

[0007] Another aspect of the present invention is an antenna device comprising a circularly polarized antenna element and a feed network. The circularly polarized antenna unit includes four ports. The feed network is coupled to the four ports and is configured to sequentially rotate a radio frequency signal. The feed network includes a first delay line and a second delay line. The first delay line and the second delay line are located in different layers stacked on top of each other.

[0008] The antenna device can include an antenna ground in a layer located between the first delay line and the second delay line. The antenna ground can provide shielding between the first delay line and the second delay line. The first delay line can include a stripline. The second delay line can include a buried microstrip.

[0009] At least a portion of the first delay line and at least a majority of the second delay line may be located within the coverage area of the circularly polarized antenna element.

[0010] The combined coverage area of the circularly polarized antenna element and the feed network may be no greater than 0.5λ by 0.5λ, where λ is the wavelength at the operating frequency of the circularly polarized antenna element.

[0011] The antenna device may include a third delay line. The first delay line may be coupled between the second delay line and the third delay line. The second delay line may be connected to a first pair of ports of four ports, and the third delay line may be connected to a second pair of ports of four ports. The second delay line and the third delay line may be in the same layer. The first delay line may provide a 180° delay, the second delay line may provide a 90° delay, and the third delay line may provide a 90° delay. The impedances of the first delay line, the second delay line, and the third delay line may provide unequal power distribution to compensate for losses in the feed network branches. The impedance range of the first delay line is from 20Ω to 40Ω, the impedance range of the second delay line is from 30Ω to 50Ω, and the impedance range of the third delay line is from 30Ω to 50Ω.

[0012] The circularly polarized antenna element and the feed network may be monolithically integrated.

[0013] The circularly polarized antenna element may include a patch. The circularly polarized antenna element may include a second patch stacked and spaced apart from the patch.

[0014] Another aspect of the present disclosure is a method of radio frequency signal transmission. The method includes sequentially rotating a radio frequency input signal with a feed network to provide a rotated version of the radio frequency input signal to four ports of a circularly polarized antenna element, the feed network including delay lines in stacked layers; and transmitting a circularly polarized radio frequency signal using the circularly polarized antenna element.

[0015] The sequential rotation may include unevenly dividing the power of the input radio frequency signal to compensate for losses in the feed network branches.

[0016] Each of the four ports may receive a rotated version of the radio frequency input signal that is rotated 90° from the corresponding rotated versions of the radio frequency input received at two adjacent ports of the four ports.

[0017] The circularly polarized antenna element may have an axial ratio of less than 4 during transmission, and the circularly polarized antenna element may have a return loss of less than -10 dB during transmission.

[0018] To summarize the present disclosure, certain aspects, advantages, and novel features of the innovation are described herein. It should be understood that not all of these advantages may be achieved in accordance with any particular embodiment. Thus, the innovation may be embodied or implemented in a manner that realizes or optimizes one or a group of the advantages taught herein, without necessarily realizing other advantages taught or suggested herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Embodiments of the present disclosure will be described by way of non-limiting examples with reference to the accompanying drawings.

[0020] Figure 1 is a schematic circuit diagram of a feed network and a circularly polarized antenna element according to an embodiment.

[0021] Figure 2 is a schematic diagram of a feed network layer and a circularly polarized antenna element stacked perpendicular to each other according to an embodiment.

[0022] Figure 3 is a schematic diagram of different layers including an example layout of a circularly polarized antenna element and a feed network according to an embodiment.

[0023] Figure 4 is an example three-dimensional schematic diagram of an antenna element and a feed network according to an embodiment.

[0024] A block diagram of a multi-turn magnetic sensing system according to an embodiment further including angle sensing.

[0025] Figure 5 includes a matching and axial ratio diagram of a circularly polarized antenna element and a feed network according to an embodiment.

[0026] Figure 6 is a schematic block diagram of a packaged module having a circularly polarized antenna element according to an embodiment. DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0027] The following detailed description of certain embodiments presents various descriptions of specific embodiments. However, the innovation described herein may be embodied in many different ways, for example, as defined and covered by the claims. In this specification, reference is made to the accompanying drawings, in which like reference numerals may represent the same or functionally similar elements. It should be understood that the elements shown in the drawings are not necessarily drawn to scale. Additionally, it should be understood that some embodiments may include more elements and / or a subset of the elements shown in the drawings. Further, some embodiments may combine any suitable combination of features from two or more of the drawings.

[0028] Aspects of the present disclosure relate to a compact single - element circularly polarized antenna and a corresponding feeding network. The circularly polarized antenna element may include four ports connected to the delay lines of the feeding network. Through the circular polarization of the antenna element, link integrity can be maintained regardless of the direction and / or relative rotation. The feeding network can be implemented by a multi - layer stack. The delay lines of the feeding network can be stacked on top of each other in different layers. Thus, the feeding network can be implemented in a compact coverage area. The delay lines of the feeding network can be used to account for the losses of the host dielectric material. A monolithic process can be used to fabricate the circularly polarized antenna element and the feeding network. The circularly polarized antenna and the feeding network according to the embodiments disclosed herein can be implemented on a single printed circuit board.

[0029] In certain applications, the circularly polarized antennas disclosed herein can be used for relatively short - range wireless links at millimeter - wave frequencies. For example, the circularly polarized antennas disclosed herein can be used for wireless links with frequencies in the range of 50 gigahertz (GHz) to 100 GHz. The circularly polarized antenna elements disclosed herein can be used for wireless communication between a master module and a slave module. Such wireless communication can be full - duplex communication.

[0030] The antennas disclosed herein can be used for wireless communication in various applications, including but not limited to communication with a robot or its parts (such as a robot arm), communication with a rotating camera, other industrial applications, communication between train carriages, communication between a vehicle and a trailer, communication between a vehicle and a rotating camera, other vehicle and / or automotive applications, etc.

[0031] For circular polarization, the radiated electric field rotates with time and space. Both the x and y transverse components of the radiated electric field can exist. The radiated electric field ε can be represented by Equation 1:

[0032]

[0033] In Equation 1, k0 represents the wave number. For right - hand circular polarization (RHCP), the y - component of the electric field lags behind the x - component. For left - hand circular polarization (LHCP), the x - component of the electric field lags behind the y - component. Regardless of how the electric field rotates, the antenna can still receive a good signal.

[0034] For circular polarization, the axial ratio AR can be represented by Equation 2, where a is the major radius of the elliptical envelope of the radiated electric field, and b is the minor radius.

[0035]

[0036] The axial ratio can represent the quality of circular polarization. The smaller the axial ratio AR, the more circular the polarization of the wave. An axial ratio AR of 0 can represent the best circular polarization.

[0037] For a circularly polarized antenna, two transverse components of an electromagnetic wave (EM) are typically excited with a 90° phase shift. A broadband design can involve exciting the two transverse components of the EM wave to produce the desired circular polarization. However, a dual-fed antenna that meets broadband specifications (e.g., 0°, -90° excitation with a T-shaped splitter and delay line) can produce radiation that is typically tilted from the broadside direction. Additionally, radiation characteristics such as the beam peak direction and axial ratio can be affected by the surrounding environment, such as the ground plane size.

[0038] Full-sequence rotational feeding with 0°, -90°, -180°, -270° four-point excitation can be applied to a circularly polarized antenna. This can make the circularly polarized antenna less sensitive to the surrounding environment than a dual-fed circularly polarized antenna. Conventional sequential rotational feeding circuits can be relatively large and occupy a relatively large footprint. Such a large-sized feeding circuit may not be ideal for a compact design. In the feeding network of an antenna, when a delay line is used to generate the desired phase, the use of a lossy substrate material and / or other losses in the feeding network can introduce asymmetry in the four-point excitation scheme. Special processing can be applied to improve the circular polarization performance in such lossy states.

[0039] The present invention provides a feeding network and a circularly polarized antenna element having a transverse dimension between 0.3λ and 0.5λ and an axial ratio bandwidth of about 10%, where λ is the wavelength at the operating frequency of the antenna. The operating frequency of the antenna can be the frequency at which the antenna transmits and / or receives RF waves. The multi-layer feeding network of the present disclosure can be advantageously implemented in a monolithic manufacturing process. Embodiments of the present disclosure include a monolithically integrated circularly polarized antenna element and a feeding network.

[0040] The feeding network disclosed herein can provide sequential rotation and can be divided into parts and stacked on different layers. In one embodiment, a 180° delay line with impedance Z2 can be implemented as a stripline under the antenna ground plane, while a 90° delay line with impedance Z1 can be implemented as a buried microstrip line above the antenna ground plane. The impedances Z1 and Z2 can provide unequal power distribution to compensate for losses in different branches of the feeding network.

[0041] Figure 1FIG. 0 is a schematic circuit diagram of an antenna device 10 including a feed network 12 and a circularly polarized antenna element 14 according to an embodiment. The feed network 12 can provide a sequential rotation of RF signals. To transmit an RF signal, the feed network 12 can provide four rotated versions of an RF input signal, including two pairs of signals that are 90° out of phase with each other, where each pair of signals is 180° out of phase with the other pair of signals. Thus, the feed network 12 can provide four RF signals having the following phases: 0°, -90°, -180°, and -270°. These four RF signals can be provided to four ports of the circularly polarized antenna element 14. The circularly polarized antenna element 14 can transmit a circularly polarized RF signal based on the signals provided at the four ports. These four parts can be symmetrically positioned around the circularly polarized antenna element 14. The feed network 12 can also delay the received circularly polarized signals provided by the four ports of the circularly polarized antenna element 14 with delay lines. Then, the received RF signals can be provided to a receiving circuit.

[0042] As Figure 1 shown, the feed network 12 can include a matching delay line 15, a first delay line 16, a second delay line 17, and a third delay line 18. The matching delay line 15 can have an impedance Zm and delay the input RF signal by 90°. The matching delay line 15 can provide impedance matching. The first delay line 16, the second delay line 17, and the third delay line 18 can together provide a sequential rotation of RF signals. The first delay line 16 can have an impedance Z 2 and provide a 180° delay. The second delay line 17 is connected to one end of the first delay line 16, and the third delay line 18 is connected to the other end of the first extension line 16. Thus, the second delay line 17 can receive an RF signal that is 180° out of phase with the RF signal received by the third delay line 18. The second delay line 17 can have a Z 1 impedance and provide a 90° delay. A first pair of ports of the antenna element 14 connected to opposite ends of the second delay line 17 can receive a pair of RF signals that are 90° out of phase with each other. The third delay line 18 can have a Z 1 impedance and provide a 90° delay. A second pair of ports of the antenna element 14 connected to opposite ends of the third delay line 18 can receive a pair of RF signals that are 90° out of phase with each other. The first pair of ports of the antenna element 14 and the second pair of ports of the antenna element 14 can receive signals that are 180° out of phase with each other due to the first delay line 16.

[0043] The impedance Z 1 and Z 2 can form a power divider. The impedance Z 1 and Z 2 can provide unequal power division to compensate for power losses associated with the paths to the respective antenna ports of the circularly polarized antenna element 14. Z is provided below1 and Z 2 Example impedance.

[0044] Figure 2 is a schematic diagram of layers of the feed network 22 and the circularly polarized antenna element 24 stacked perpendicular to each other according to an embodiment. Figure 2 Also shown is a metal stack including a plurality of metal layers and a plurality of vias, in which the elements of the feed network 22 and the circularly polarized antenna element 24 are implemented. The combination of the feed network 22 and the circularly polarized antenna element 24 occupies a compact area, where the delay line of the feed network 22 is located below the coverage area of the circularly polarized antenna unit 24 and at least partially within its coverage area. This utilizes the area below the circularly polarized antenna element 24 as the delay line of the feed network 22. In certain embodiments, the combined coverage area of the feed network 22 and the circularly polarized antenna element 24 is no greater than 0.5λ by 0.5λ. In some embodiments, the combined coverage area is in the range of 0.3λ by 0.3λ to 0.5λ by 0.5λ.

[0045] The feed network 22 is Figure 1 an example of the feed network 12. The feed network 22 includes a matching delay line 25, a first delay line 26, a second delay line 27, and a third delay line 28. These delay lines can be referred to as feed lines. In certain embodiments, one or more of the delay lines 25, 26, 27, and 28 may include one or more bends.

[0046] As Figure 2 shown, the matching delay line 25 and the first delay line 26 are located in a layer above the partial ground plane 29. The partial ground plane 29 can be implemented in the bottom layer of the Figure 2 metal stack. The matching delay line 25 and the first delay line 26 can be located in layer 7 of the Figure 2 metal stack. The matching delay line 25 may have an impedance Zm and delay the RF signal by 90°. The first delay line 26 has an impedance Z 2 and provides a 180° delay. In certain applications, the first delay line 26 may provide a delay in the range of 170° to 190°, such as in the range of 175° to 185°. The first delay line 26 can be a stripline. The first delay line 26 is a conductive transmission line.

[0047] The antenna ground 30 can be located in the layer between the first delay line 26 and the second delay line 27. The antenna ground 30 can be located in layer 6 of the Figure 2 metal stack. The antenna ground 30 can provide shielding between the first delay line 26 and the second delay line 27. The antenna ground 30 can also provide shielding between the first delay line 26 and the third delay line 28. The antenna ground 30 can provide ground connections to the first, second, and third delay lines 26, 27, and 28, respectively.

[0048] The second delay line 27 is connected to one end of the first delay line 26 through a via 31 that extends through the antenna ground 30. The third delay line 28 is connected to the other end of the first delay line 26 through a via 32 that extends through the antenna ground 30. The second delay line 27 and the third delay line 28 can be in Figure 2 layer 5 of the metal stack of 1 and provide a 90° delay. Each of the second delay line 27 and the third delay line 28 can provide half or approximately half of the delay provided by the first delay line 26. In some applications, the second delay line 27 and / or the third delay line 28 can provide a delay in the range of 80° to 100°, for example, in the range of 85° to 90°.

[0049] The ends of the second delay line 27 are connected to the first pair of ports Port 2 and Port 3 of the circularly polarized antenna element 24 through vias 33 and 34. The ends of the third delay line 28 are connected to the second pair of ports Port 1 and Port 4 of the circularly polarized antenna element 24 through vias 35 and 36. The ports Port 1, Port 2, Port 3, and Port 4 of the circularly polarized antenna element 24 receive RF signals that are fully sequentially rotated. The signals received by each port are 90° out of phase with the signals of two adjacent ports. The ports Port 1, Port 2, Port 3, and Port 4 can be symmetrically positioned around the circularly polarized antenna element 24, for example, as shown in the figure.

[0050] The circularly polarized antenna element 24 includes a bottom patch 37 and a top patch 38. To obtain a larger bandwidth, a larger spacing may be required between the bottom patch 37 and the second and third delay lines 27 and 28. As Figure 2 shown, the bottom patch 37 and the second and third delay lines 27 and 28 are located in non - adjacent layers, with one layer in between. This can increase the bandwidth with respect to the bottom patch 37 located in the layer adjacent to the second and third delay lines 27 and 28. The bottom patch 37 can be in Figure 2 layer 3 of the metal stack of Figure 2 The top patch 38 can be located in

[0051] layer 1 or the top layer of the metal stack. As shown in the figure, layer 1 can be the top layer of the metal stack. The area of the bottom patch 37 can be approximately the same as the area of the top patch 38.

[0052] AlthoughFigure 2 The circularly polarized antenna element 24 including a bottom patch 37 and a top patch 38 is shown, but in some embodiments, the circularly polarized antenna unit may include a single patch. The patch antenna element with the feeding network 22 can be implemented in a monolithic process. Thus, the feeding network 22 and the circularly polarized antenna element 24 can be monolithically integrated. Any other suitable antenna element can be implemented with the feeding network disclosed herein.

[0053] If the losses can be ignored, the impedance of the second delay line 27 and the third delay line 38 1 can be 50 Ω, and the impedance Z of the first delay line 26 2 can be 25 Ω to achieve equal power distribution. The impedance Z 1 a and the impedance Z 2 can be different from these values to compensate for the losses. By changing the impedance Z 1 from 50 Ω and / or changing the impedance Z 2 from 25 Ω, more power can be provided to the branches of the feeding network 22 with larger losses. In some cases, the impedance Z 1 and the impedance Z 2 can be determined by numerical optimization based on electromagnetic simulation. To compensate for the losses in the feeding network 22, the impedance Z 1 can be in the range of 30 Ω to 50 Ω, and the impedance Z 2 can be in the range of 20 Ω to 40 Ω. The impedance Zm can also be selected to compensate for the losses associated with the feeding network 12. The impedance Zm can be in the range of 20 Ω to 40 Ω.

[0054] Figure 3 Schematic diagrams of different layers 41 to 47 including an example layout of the circularly polarized antenna element 24 and the feeding network 22 according to an embodiment. Figure 2 The layout has a coverage area of 0.4λ x 0.4λ, where the dielectric constant is in the range of 2.5 to 4. Figure 3 The layout has a coverage area of 0.4λ x 0.4λ, where the dielectric constant is in the range of 2.5 to 4.

[0055] Referring to Figure 3, the top patch 38 is included in the first layer 41. The top patch 38 can be separated from the bottom path 37 by the dielectric material of the second layer 42. The bottom patch 37 can be included in the third layer 43. The first pair of ports of the bottom patch 37 can be connected to the second delay line 27 through vias 33 and 34 extending from the third layer 43 through the fourth layer 44 to the fifth layer 45. The second pair of ports of the bottom patch 37 can be connected to the third delay line 28 through vias 35 and 36 extending from the third layer 43 through the fourth layer 44 to the fifth layer 45. The fifth layer 45 includes the second delay line 27 and the third delay line 28. The sixth layer 46 includes the antenna ground 30, and vias 31 and 32 pass through it. The matching delay line 25 and the first delay line 26 are implemented in Figure 3 the seventh layer 47 in. The vias 31 and 32 connecting the first delay line 26 to the second delay line 27 and the third delay line 28 extend from the seventh layer 47 to the fifth layer 45.

[0056] Figure 4 is according to an embodiment Figure 2 example three-dimensional schematic diagram of the antenna element 24 and the feeding network 22. Figure 4 Includes a scale, showing the dimensions of the example antenna element 24 and the feeding network 22. As shown, at least a part of the first delay line 26 and at least most of the second delay line 27 can be located within the coverage area of the circularly polarized antenna element 24.

[0057] Figure 5 Includes according to an embodiment Figure 2 matching and axial ratio diagrams of the circularly polarized antenna element and the feeding network. For some applications, an axial ratio less than 4 may be required. For some of these applications, an axial ratio less than 3 may be required. The axial ratio values are plotted against frequency in the Figure 5 bottom chart. The points with an axial ratio of 4 and an axial ratio of 3 are shown on this graph. Figure 5 The top chart in is for matching and plots the return loss against frequency. For some applications, a return loss less than -10 decibels (dB) may be required. Figure 5 Shows the ideal performance of the antenna device including the circularly polarized antenna element 24 and the feeding network 22 in the frequency range from about 58.6 GHz to about 64 GHz, where the axial ratio is less than 4 and the return loss is less than -10 dB.

[0058] Figure 6 is a schematic block diagram of a packaged module 60 having a circularly polarized antenna element 24 according to an embodiment. The packaged module 60 can be a packaged radio frequency module. As Figure 6As shown, some packaging modules 60 may include a single circularly polarized antenna element 24. A feed network according to any suitable principles and advantages disclosed herein may be implemented under the circularly polarized antenna element 24. The module 60 may include integrated circuits 62 and 64. The integrated circuits 62 and 64 are co-packaged with the circularly polarized antenna element 24 in the packaging module 60. The integrated circuits 62 and 64 may provide any suitable circuit functions. For example, the integrated circuit 62 may include radio frequency front-end circuitry that communicates with the circularly polarized antenna element 24. As another example, the integrated circuit 64 may include baseband processing circuitry. The packaging module 60 may include any other suitable circuitry for a particular application. For example, in some applications, the packaging module 60 may include a test antenna (not shown) that is inactive during typical operation.

[0059] Although the packaging module 60 is shown as having a single circularly polarized antenna element 24, an array of circularly polarized antenna elements according to any suitable principles and advantages disclosed herein may be implemented in certain applications. As an example, in some applications, a 4 by 4 array of circularly polarized antenna elements may be implemented.

[0060] The antenna devices disclosed herein may be implemented in any suitable application that benefits from circularly polarized antennas. Any suitable principles and advantages disclosed herein may be implemented in systems, devices, and methods that include circularly polarized antennas. The principles and advantages described herein may be implemented in a variety of devices. Examples of such devices may include, but are not limited to, consumer electronics products, components of consumer electronics products, electronic test equipment, in-vehicle electronics, industrial electronics, communication infrastructure (such as wireless communication infrastructure), etc. The electronics products may include, but are not limited to, wireless communication devices, mobile phones (such as smart phones), handheld computers, tablet computers, laptop computers, wearable computing devices, in-vehicle electronic systems, radios, wearable health monitoring devices, base stations such as cellular base stations, access points, repeaters, etc. In addition, the devices may include unfinished products.

[0061] Unless the context clearly requires otherwise, throughout the specification and claims, words such as "comprising", "including", "containing", etc. shall be construed in an inclusive sense rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to", the term "coupled" or "connected" as commonly used herein refers to two or more elements that can be directly connected or connected through one or more intermediate elements. Thus, although the various schematic diagrams shown in the figures depict exemplary arrangements of elements and components, there may be additional intervening elements, devices, features or components in the actual embodiments (assuming that the functions of the depicted circuits are not adversely affected). Additionally, the terms "herein", "above", "below" and words of similar import used in this application shall refer to the entire application rather than any particular part of this application. Where the context permits, words in the detailed description using the singular or plural may also respectively include the plural or singular. When referring to a list of two or more items, the word "or" is intended to cover all of the following interpretations of that word: any item in the list, all items in the list, and any combination of items in the list. All numerical values provided herein are intended to include similar values within the measurement error.

[0062] Furthermore, unless specifically stated otherwise or understood in the context in which it is used, conditional language used herein, such as "can", "may", "could", "for example", "such as", etc., generally intends to convey that certain embodiments include, while other embodiments do not include certain features, elements and / or states.

[0063] The teachings of the embodiments provided herein can be applied to other systems, not necessarily the systems described above. The elements and actions of the various embodiments above can be combined to provide further embodiments. The actions of any method discussed herein can be appropriately performed in any order. Additionally, the actions of any method discussed herein can be performed serially or in parallel as needed.

[0064] While certain embodiments of the invention have been described, these embodiments have been presented by way of example only and are not intended to limit the scope of the disclosure. In fact, the novel circuits, methods, and systems described herein may be embodied in a variety of other forms. Additionally, various omissions, substitutions, and changes may be made to the forms of the circuits, methods, devices, and systems described herein without departing from the spirit of the disclosure. For example, while the disclosed embodiments are presented in a given arrangement, alternative embodiments may perform similar functions using different components and / or circuit topologies, and some elements may be deleted, moved, added, subdivided, combined, and / or modified. Each of these elements may be implemented in a variety of different ways. Any suitable combination of the elements and acts of the various embodiments described above may be combined to provide further embodiments. The appended claims and their equivalents are intended to cover forms or modifications that fall within the scope and spirit of the disclosure. Accordingly, the scope of the invention is defined by reference to the claims.

[0065] Although the claims presented here are filed with the United States Patent and Trademark Office in a single dependent format, it should be understood that any claim may depend on any prior claim of the same type, unless this is clearly technically infeasible.

Claims

1. An antenna device, comprising: A circularly polarized antenna element, comprising a first pair of ports and a second pair of ports; as well as A feeding network is configured to sequentially rotate the radio frequency signal, the feeding network comprising: first delay line; a second delay line connected to the first pair of ports, wherein the second delay line and the first delay line and the second delay line are located in different layers stacked with each other, and wherein the antenna ground is located between the first delay line and the second delay line and provides shielding therebetween; and A third delay line is connected to the second pair of ports, wherein the first delay line is coupled between the second delay line and the third delay line. 2 . The antenna device of claim 1 , wherein the impedances of the first delay line, the second delay line, and the third delay line provide unequal power distribution to compensate for losses in feed network branches.

3. The antenna device of claim 1, wherein the circularly polarized antenna element comprises a patch, and wherein the circularly polarized antenna element and the feed network are monolithically integrated.

4. An antenna device, comprising: A circularly polarized antenna element including four ports; as well as A feeding network is coupled to the four ports and configured to sequentially rotate the radio frequency signal, the feeding network comprising a first delay line and a second delay line, the first delay line and the second delay line being located in different layers stacked with each other. 5 . The antenna device of claim 4 , further comprising an antenna ground located in a layer between the first delay line and the second delay line, the antenna ground providing shielding between the first delay line and the second delay line. 6 . The antenna device of claim 5 , wherein the first delay line comprises a stripline and the second delay line comprises a buried microstrip.

7. The antenna device of claim 4, wherein at least a portion of the first delay line and at least a majority of the second delay line are located within a coverage area of ​​the circularly polarized antenna element.

8. The antenna device of claim 4, wherein the combined coverage area of ​​the circularly polarized antenna element and the feed network is no greater than 0.5λ by 0.5λ, where λ is the wavelength at the operating frequency of the circularly polarized antenna element.

9. The antenna device according to claim 4, further comprising a third delay line, wherein the first delay line is coupled between the second delay line and the third delay line, wherein the second delay line is connected to a first pair of ports of the four ports, and wherein the third delay line is connected to a second pair of ports of the four ports. 10 . The antenna device according to claim 9 , wherein the second delay line and the third delay line are located in the same layer.

11. The antenna device of claim 9, wherein the first delay line provides a 180° delay, the second delay line provides a 90° delay, and the third delay line provides a 90° delay.

12. The antenna device of claim 9, wherein the impedances of the first delay line, the second delay line, and the third delay line provide unequal power distribution to compensate for losses in feed network branches. 13 . The antenna device according to claim 12 , wherein an impedance of the first delay line is in a range of 20Ω to 40Ω, an impedance of the second delay line is in a range of 30Ω to 50Ω, and an impedance of the third delay line is in a range of 30Ω to 50Ω.

14. The antenna device of claim 4, wherein the circularly polarized antenna element and the feed network are monolithically integrated.

15. The antenna device of claim 4, wherein the circularly polarized antenna element comprises a patch. 16 . The antenna device of claim 15 , wherein the circularly polarized antenna element comprises a second patch stacked and spaced apart from the patch.

17. A method for transmitting a radio frequency signal, the method comprising: sequentially rotating the RF input signal with a feed network to provide rotated versions of the RF input signal to four ports of the circularly polarized antenna element, the feed network comprising delay lines in a stacked layer; and The circularly polarized antenna element is used to transmit a circularly polarized radio frequency signal.

18. The method of claim 17, wherein the sequential rotation includes dividing the power of the input RF signal unevenly to compensate for losses in feed network branches.

19. The method of claim 17, wherein each of the four ports receives a rotated version of the RF input signal that is rotated 90° from a corresponding rotated version of the RF input received at two adjacent ports of the four ports.

20. The method of claim 17, wherein the circular antenna element has an axial ratio of less than 4 when transmitting, and the circularly polarized antenna element has a return loss of less than -10 dB when transmitting.

Images