Technical Field

[0001] This disclosure relates generally to the field of antennas, and more particularly to single feed circular polarization antennas with two or more stacked antenna elements.

Background

[0002] Typically a circular polarization antenna has two feeds. A typical circular polarization antenna comprises a 90 degree hybrid circuit for receiving a signal, from an amplifier, splitting the signal into vertical and horizontal components, and feeding each component to a separate antenna element. The 90 degree hybrid introduces signal losses, such as 1 -2 dB signal loss. Typical circular polarization antennas are also relatively narrow band width antennas. It is desirable to create a single feed circular polarization antenna that is relatively broad band while minimizing signal loss.

Summary

[0003] In accordance with an example embodiment, a single feed circular polarization stacked antenna element antenna is disclosed. The antenna may comprise: a single feed, wherein the single feed is the one and only feed to the antenna element antenna; a first antenna element coupled to the single feed, the first antenna element comprising a first feature configured to communicate a first electromagnetic wave having a particular circular polarization; a second antenna element coupled to the first antenna element, the second antenna element comprising a second feature configured to communicate a second electromagnetic wave having the particular circular polarization; and a first dielectric located between the first antenna element and the second antenna element, wherein the first antenna element is rotated relative to the second antenna element to account for a phase difference between the first and second electromagnetic waves due to the first dielectric, so that the first and second electromagnetic waves combine coherently.

[0004] In an example embodiment, a method of making a single feed circular polarization stacked antenna element antenna is disclosed. The method may comprise: coupling a first antenna element to a single feed, wherein the single feed is the one and only feed to the antenna element antenna, wherein the first antenna element comprises a first feature configured to communicate a first electromagnetic wave having a particular circular polarization; coupling a second antenna element to the first antenna element, the second antenna element comprising a second feature configured to communicate a second electromagnetic wave having the particular circular polarization; and locating a dielectric between the first antenna element and the second antenna element, wherein the first antenna element is rotated relative to the second antenna element to account for a phase difference between the first and second electromagnetic waves due to the dielectric, so that the first and second electromagnetic waves combine coherently.

Brief Description of the Drawings

[0005] The foregoing and other features of the present invention will become apparent to those skilled in the art to which the present invention relates upon reading the following description with reference to the accompanying drawings, in which:

[0006] FIG. 1 illustrates a side view of a single feed stacked antenna element circular polarization antenna, in accordance with example embodiments;

[0007] FIGS. 2A and 2B illustrate perspective views of a single feed stacked antenna element circular polarization antenna, in accordance with example embodiments;

[0008] FIG. 3 illustrates another perspective view of a single feed stacked antenna element circular polarization antenna, in accordance with example embodiments;

[0009] FIG. 4 illustrates side views of various example embodiments of a single feed stacked antenna element circular polarization antenna;

[0010] FIG. 5 is a top view of a planar array antenna, in accordance with example embodiments; and

[0011] FIG. 6 illustrates a method for making a single feed stacked antenna element circular polarization antenna, in accordance with example embodiments.

Detailed Description

[0012] While exemplary embodiments are described herein in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that logical electrical and mechanical changes may be made without departing from the spirit and scope of the invention. Thus, the following detailed description is presented for purposes of illustration only.

[0013] In accordance with an example embodiment, a single feed circular polarization stacked antenna element (e.g., patch) antenna is disclosed. In an example embodiment, the antenna comprises at least two antenna elements, stacked with a dielectric located therebetween, and the antenna comprises a single feed. In this example embodiment, the antenna elements are rotated relative to each other to account for a phase difference between the electromagnetic waves associated with each element that is due to the dielectric located between them, so that the electromagnetic waves combine coherently. [0014] With reference now to FIG. 1 , in an example embodiment, a single feed circular polarization stacked antenna element antenna 100 is disclosed. In an example embodiment, the antenna comprises: a single feed 105, a first antenna element 1 10 coupled to the single feed, a second antenna element 120 coupled to the first antenna element 1 10, and a dielectric 1 15 located between the first antenna element 110 and the second antenna element 120. In various example embodiments, the antenna 100 further comprises a ground plane 180 separated from the first antenna element 1 10 by at least a further dielectric 170. In this further example embodiment, the ground plane comprises an opening through which signal from the single feed 105 may be electrically coupled (e.g. through a via (shown in dashed lines) or capacitively coupled to first antenna element 1 10.

[0015] In an example embodiment, the single feed 105 is configured for transmitting and/or receiving of signals by antenna 100. Thus, the antenna 100 may be a transmitter, a receiver, or a transceiver. In an example embodiment, the single feed 105 is the only feed that is coupled to the first antenna element. Stated another way, one and only one feed is connected to the first antenna element. In yet another example embodiment, the antenna 100 does not comprise a 90 degree hybrid. In an example embodiment, the antenna 100 is 90 degree hybrid-less. Stated another way, the antenna 100 does not split/combine a signal communicated (transmit/receive) with the antenna.

[0016] In an example embodiment, the antenna 100 further comprises a single amplifier for amplifying a signal provided to the first antenna element 1 10.

[0017] In an example embodiment, the first and second antenna elements 110/120 are each planar antenna elements. In another example embodiment, each planar antenna element comprises a metallization layer disposed on a side of a dielectric. Moreover, in accordance with various example embodiments, the first and second antenna elements 1 10/120 are each patch antennas. In accordance with further example embodiments, each antenna element may comprise a metallization layer on a side of a dielectric. Although described herein in terms of “antenna elements,” it should be understood that the accompanying descriptions can be equally applicable to “planar antenna elements” and “patches,” as applicable. [0018] In an example embodiment, the dielectric 115 may comprise any suitable dielectric(s) located between the first antenna element 1 10 and the second antenna element 120. In one example embodiment, the dielectric comprises a single dielectric comprising a single dielectric material. For example, the dielectric may comprise an air gap, a vacuum, a glass, and/or any suitable dielectric material. In another example embodiment, the dielectric may comprise more than one dielectric, e.g., a first dielectric and a second dielectric. For example, the first dielectric may comprise a glass material and the second dielectric material may comprise an air gap. Moreover, any suitable number of dielectrics may be used to form the dielectric. The dielectric may further be formed in a dielectric layer (or dielectric layers) between the first antenna element 1 10 and the second antenna element 120.

[0019] In an example embodiment, the first antenna element 1 10 is coupled to the single feed 105. In this example embodiment, the first antenna element 110 may be coupled to the single feed 105 by a via from the single feed 105 that is electrically connected to the first antenna element 1 10. The coupling may be configured to send and/or receive signals between the first antenna element 110 and the single feed 105. In another example embodiment, the first antenna element 1 10 may be coupled to the single feed electromagnetically (i.e., the first antenna element may be capacitively coupled to the single feed 105).

[0020] In an example embodiment, the second antenna element 120 is coupled to the first antenna element 1 10. In this example embodiment, the first and second antenna elements 110/120 may be coupled to each other electrically by way of a via 1 16 between them and through the dielectric 1 15. It is noted that the via 1 16 may be configured to protect against electrostatic discharge, radiation, charging effects, and/or discharge. Moreover, although the coupling between the first and second antenna elements 1 10/120 may be electrical, it should be understood that there may also be some degree of electromagnetic coupling between the first and second antenna elements.

[0021] In another example embodiment, the first and second antenna elements 1 10/120 may be connected only electromagnetically, wherein the second antenna element functions as a passive device (e.g., a passive radiator/receiver).

[0022] With reference now to FIGS. 2A and 2B, in various example embodiments, an antenna 200 (similar to antenna 100 discussed in connection with FIG. 1 ) may comprise two or more antenna elements (including a first antenna element 210A and second antenna element 220A). In an example embodiment, the two of more antenna elements may each comprise a circular geometry. In other example embodiments, the two or more antenna elements may each comprise square geometry, square with beveled corners geometry, or any suitable geometry for electromagnetic communication. Moreover, in accordance with various example embodiments, the geometries of the two or more antenna elements may differ from one antenna element to the next.

[0023] Although the geometry between the two or more antenna elements may be similar, as illustrated in FIG. 2B, the size may differ between the two or more antenna elements. For example, the first antenna element 21 OB may be scaled to be larger than the second antenna element 220B. Any suitable scaling difference may be used between the two or more antenna elements. In other example embodiments, as illustrated in FIG. 2A, the size of the first antenna element 210A is the same as the size of the second antenna element 220A.

[0024] In an example embodiment, each antenna element (or each planar antenna element, each patch) of the two or more antenna elements is configured to communicate an electromagnetic wave (e.g. transmit, receive, or transceive an electromagnetic wave). In an example embodiment, each antenna element comprises a feature configured to communicate an electromagnetic wave having a particular circular polarization. Thus, in an example embodiment, the first antenna element 210A/B comprises a first feature 211 A/B configured to communicate a first electromagnetic wave having a particular circular polarization, and the second antenna element 220A/B comprises a second feature 221 A/B configured to communicate a second electromagnetic wave having the particular circular polarization.

[0025] As illustrated in both FIGs. 2A and 2B, the feature 21 1 A/221 A/21 1 B/221 B, in an example embodiment is a slot. In other example embodiments, the feature may have a triangular or trapezoidal shape, a curved shape, stepped shape, or the like. In further example embodiments, the ‘feature’ may comprise multiple attributes such as radially extending slots on both sides of the axis (e.g. Z axis) of the stacked antenna elements. Moreover, the feature 211 A/221 A/21 1 B/221 B may be any geometric feature in the antenna element that causes polarization in a particular direction. Although shown herein as an internal notch, the feature could also be an external tab or the like. In an example embodiment, the feature 21 1 A/B comprises the same shape as that of feature 221 A/B and/or the features of other antenna elements in the stack. However, the feature 21 1 A/B can have a different shape from that of feature 221 A/B. In an example embodiment, the first antenna element may comprise a first feature associated with a first phase in a first direction, and the second antenna element may comprise a second feature associated with a second phase in a second direction. As described further herein, the relative rotational orientation between the antenna elements facilitates coherence of the signals communicated with both of the first and second antenna elements.

[0026] Although the geometry between the two or more features may be similar, the size of the features for each antenna element may differ between the two or more antenna elements. For example, as illustrated in FIG. 2B, the first feature 21 1 B may be scaled to be larger than the first feature 221 B. Any suitable scaling difference may be used between the two or more features. In other example embodiments, as illustrated in FIG. 2A, the size of the first feature 21 1 A is the same as the size of the second feature 221 A.

[0027] In an example embodiment, the first antenna element 21 OA/B is rotated relative to the second antenna element 220A/B to account for a phase difference between the respective first and second electromagnetic waves due to the dielectric, so that the first and second electromagnetic waves combine coherently. In one example embodiment, this relative rotation may be represented by a rotation amount (e.g. measured in radians or degrees). In an example embodiment, a zero or 360 degree rotation represents alignment of the first and second features. In an example embodiment, the second antenna element is rotated relative to the first antenna element so that the second feature is out of alignment with the first feature. Stated another way, in an example embodiment, the first feature is not in alignment with the second feature.

[0028] In an example embodiment, the “due to the dielectric” limitation comprises any and all phase differences that may arise due to the second electromagnetic waves passing through the dielectric. In particular, the thickness of the dielectric material (e.g. wavelength between the first antenna element and second antenna element) may impact the amount of phase difference between the first and second electromagnetic waves. In an example embodiment, the dielectric layer has a dielectric layer thickness comprising the distance between the first surface of the dielectric and the second surface of the dielectric, opposite the first surface. Moreover, the material of the dielectric may impact the amount of phase differential between the first and second electromagnetic waves. Thus, the degree of differential rotation between two antenna elements may correspond to a phase propagation through the dielectric layer between them. Moreover, it is noted that the dielectric, in various embodiments, may comprise more than one type of dielectric layer, and/or more than one type of dielectric material (including air or a vacuum). Therefore, the amount of rotation may, in embodiments comprising a multilayer and/or multi-material dielectric, account for the sum of the phase differences due to each dielectric layer / material.

[0029] Multi-element antenna stacks

[0030] With reference now to FIG. 3, in accordance with various example embodiments, an antenna 300 may comprise more than two stacked antenna elements. For example, the antenna 300 may comprise N stacked antenna elements (where N is an integer greater than 2). In this example embodiment, the N antenna elements may be arranged in a stack in numerical order having the first antenna element 310 furthest from a radiating surface 301 of the antenna, and the Nth antenna element closest to the radiating surface 301. The second antenna element 320 may be the antenna element second furthest from the radiating surface 301 after the first antenna element 310. In an example embodiment, the antenna 100 has a bandwidth that is broader than a similar antenna having N-1 stacked antenna elements.

[0031] In this example embodiment, the N stacked antenna elements may be separated by a total of N-1 dielectrics. For example, the first and second antenna elements 310/320 may be separated by a first dielectric 31 1 , the second and (N-1 )th antenna elements may be separated by an (N-2)th dielectric, and the (N-1 )th and Nth antenna elements may be separated by an (N-1 )th dielectric. In an example embodiment, the antenna 300 may further comprise a ground plane 380 and a further dielectric 370 located between the ground plane 380 and the first antenna element 310.

[0032] Thus, in an example embodiment, the first and second antenna elements 310/320 may be located on opposite sides of a first dielectric 311 . For example, a first planar antenna element may comprise a first metallization layer on a first side of the first dielectric, and the second planar antenna element may comprise a second metallization layer on a second side of the first dielectric opposite the first side.

[0033] In this example embodiment, there may be a progression of rotation between adjacent antenna elements. As an example, the degrees of rotation X1 between the first antenna element 310 and the second antenna element 320 may be smaller than the degrees of rotation X2 between the first antenna element and the (N-1 )th antenna element, which is smaller than the degrees of rotation X3 between the first antenna element and the Nth antenna element. Stated another way, in an example embodiment, the rotation of each antenna element of a plurality of stacked antenna elements, relative to the first antenna element, is progressively greater for each antenna element in the direction from the interior of the antenna toward the radiating surface 301 of the antenna. In an example embodiment, where the degrees of rotation between the first and second antenna elements is the same as the degrees of rotation between the second and third antenna elements, one may expect that the dielectric material and thickness of the respective interposing dielectrics would be the same.

[0034] With reference now to FIG. 4, various example stacked antenna embodiments are illustrated. In an example embodiment, a single feed circular polarization stacked antenna element antenna 400A comprises: a first planar antenna element 410A comprising a first metallization layer 412A on a first side of a first dielectric 41 1 A; and a second planar antenna element 420A comprising a second metallization layer 422A on a first side of a second dielectric 421 A. The first and second planar antenna elements 410A/420A may be stacked, separated by solder balls 450A to form an air gap 460A therebetween.

[0035] In the various example embodiments of FIG. 4, the antennas 400A/400B/400C respectively further comprise respective ground planes 480A/480B/480C adjacent to the respective first dielectrics 411 A/41 1 B/41 1 C. In these example embodiments, the ground planes 480A/480B/480C respectively comprise a metal layer with an opening through which signal from the single feed 405A/405B/405C may be electrically coupled to the first metallization layer 412A/412B/412C (e.g. through a via through respective dielectrics 411 A/41 1 B/41 1 C), or may be capacitively coupled to the first metallization layer.

[0036] In accordance with another example embodiment, a single feed circular polarization stacked antenna element antenna 400B comprises: a first planar antenna element 410B comprising a first metallization layer 412B on a first side of a first dielectric 411 B; a second planar antenna element 420B comprising a second metallization layer 422B on a first side of a second dielectric 421 B; and a third planar antenna element 430B comprising a third metallization layer 432B on a second side of the second dielectric 421 B opposite the first side, the first side of the first dielectric 41 1 B being proximate the second dielectric 421 B. The first, second and third planar antenna elements 410B/420B/430B may be stacked with the first and third metallization layers 412B/432B separated by air gap 460B therebetween formed by solder balls 450B located between the first and second dielectrics 41 1 B/421 B. The first metallization layer 412B may be electromagnetically coupled to the second and third metallization layers 422B/432B.

[0037] In accordance with another example embodiment, a single feed circular polarization stacked antenna element antenna 4000 comprises: a first planar antenna element 4100 comprising a first metallization layer 4120 on a first side of a first dielectric 4110, and a second planar antenna element 4200 comprising a second metallization layer 4220 on a first side of a second dielectric 4210. The second planar antenna element 4200 may be stacked on the first planar antenna element 4100, such that the first metallization layer 4120 is adjacent to a second side of the second dielectric 4210 opposite the first side. In this example embodiment, there is in essence no air gap 4600 between the first and second dielectrics, as the first metallization layer 4120 is quite thin (FIG. 4 is not drawn to scale). The first and second planar antenna elements 4200/41 OC may be connected to each other, in an example embodiment, with an adhesive, or any other suitable method of connecting the two components. In other example embodiments, a solder ball may be placed between the first metallization layer 4120 and the second dielectric 4210 to form an air gap 4600. The first and second metallization layers 4120/4220 may be electrically coupled to each other by way of a via 4060 through the second dielectric 4210.

[0038] With reference now to FIG 5, in an example embodiment, a phased array antenna 590 may comprise a plurality of single feed circular polarization stacked antenna element antennas (e.g., 500A or 500B), wherein for each of the plurality of antennas the first antenna element is rotated relative to the second antenna element to account for a phase difference between the first and second electromagnetic waves of respective first and second antenna elements due to the dielectric, so that the first and second electromagnetic waves combine coherently. In one example embodiment, there may be a differential rotation between the first antenna element of antenna 500A and the first antenna element of antenna 500B. In another example embodiment, all of the antennas in a first group 591 may have their differential rotation between their stacked antenna elements be similar to that of the differential rotation in each of the antennas in a second group 592, but a “reference antenna element” (e.g., the first antenna element or bottom antenna element) in one group may be oriented rotated differently from that of another group. It should be noted that any of the antenna elements in the stack may be the reference antenna element, and rotation of other antenna elements may be measured from such reference antenna element. Nevertheless, regardless of which antenna element is the reference antenna element, in various example embodiments, the amount of rotation is configured to facilitate coherent signal communication with all of the stacked antenna elements by accounting for the phase shift due to the various dielectrics as disclosed herein. [0039] Stated another way, a single layer antenna array may be configured with a plurality of single feed circular polarization stacked antenna element antennas, where each antenna belongs to one of four (or any other suitable number) groups and within each group there is relative rotation between the various antenna elements of the stack as disclosed herein, but as between the four groups, the first antenna element (e.g. bottom antenna element) of each group is rotated 90 degrees from the other first antenna elements of the other groups. In this example embodiment, the other antenna elements of the respective stacks are rotated relative to the first antenna element.

[0040] In another example embodiment, the rotation schema of one or more of the of the plurality of antennas is an n*180 degree rotation.

[0041] For example, if an R degree rotation is desired between two stacked antenna elements, e.g., R=10 degrees, then the first antenna element of antenna 500A may start with a rotation of 10 degrees (10+0*180), with a rotation of 190 degrees (10+1 *180), with a rotation of 10 degrees (10+2*180=370=10), or with a rotation of -170 degrees (10+(- 1 )*180). The first antenna element of antenna 500B may have one of these rotations as well. In an example embodiment, the first antenna elements of antenna 500A differ in rotation from that of antenna 500B by 180 degrees.

[0042] In another example, first antenna element of antennas in a first group 591 may differ in rotation from that of the first antenna element of antennas in a second group 592. Thus, each antenna in the phased array has differential rotation for coherent combination of the stacked antenna elements therein, but some do so with a rotation that is 180 different from the others.

[0043] In an example embodiment, and with reference to FIG. 6, a method 600 of making a single feed circular polarization stacked antenna element antenna is disclosed. The method 600 may comprise: coupling 610 a first antenna element to a single feed, wherein the single feed is the one and only feed to the antenna element antenna, wherein the first antenna element comprises a first feature configured to communicate a first electromagnetic wave having a particular circular polarization; coupling 620 a second antenna element to the first antenna element, the second antenna element comprising a second feature configured to communicate a second electromagnetic wave having the particular circular polarization; and locating 630 a dielectric between the first antenna element and the second antenna element, wherein the first antenna element is rotated relative to the second antenna element to account for a phase difference between the first and second electromagnetic waves due to the dielectric, so that the first and second electromagnetic waves combine coherently.

[0044] In an example embodiment, a method of manufacturing the antenna may comprise creating the first dielectric layer 4110 with a via and metallization layer using any suitable manufacturing technique. Next, 3D printing may be used to print layers on top of the first dielectric and metallization layer. For example, a second dielectric layer 421 C with via 4060 may be printed on top of the first dielectric 41 1 C and first metallization layer 412C. In this example embodiment, the three dimensional printing may facilitate creating an air gap between the first metallization layer 412C and the second dielectric 4210. Other suitable 3D printing techniques may be used to manufacture the antenna disclosed herein.

[0045] Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of any or all the claims. As used herein, the terms “includes,” “including,” “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Further, no element described herein is required for the practice of the invention unless expressly described as “essential” or “critical.”