BROADBAND UNMANNED AERIAL VEHICLE (UAV) PATCH ANTENNA

Abstract

Embodiments of the present disclosure relate to a UAV comprising a fuselage, a rotor, and a patch antenna element. The patch antenna element, which is provided from a patch antenna stack-up, is conformally disposed on an outer surface of the UAV's fuselage. The patch antenna comprises a first substrate, patch conductor, intermediate substrate, bottom substrate, and ground plane. The patch conductor is disposed on a top surface of the first substrate. A first surface of the intermediate substrate, which is a magneto-dielectric material, is disposed on a bottom surface of the first substrate. A top surface of the bottom substrate is disposed on a second surface of the intermediate substrate. A ground plane conductor is disposed on a bottom surface of the bottom substrate.

Claims

1. An unmanned aerial vehicle (UAV) comprising: a fuselage having an inner surface and an outer surface; at least one rotor coupled to said fuselage; and a patch antenna element conformally disposed on the outer surface of said UAV fuselage, said patch antenna provided from a patch antenna stack-up comprising: a first substrate having top and bottom opposing surfaces; a patch conductor disposed on the top surface of said first substrate; an intermediate substrate having a first surface and a second opposing surfaces, with the first surface of said intermediate substrate disposed on the bottom surface of said first substrate, said intermediate substrate corresponding to a magneto-dielectric material; a bottom substrate having top and bottom opposing surfaces, with the top surface of said bottom substrate disposed on the second surface of said intermediate substrate, such that said intermediate magneto-dielectric substrate is provided as an inner layer in the patch antenna stack-up; and a ground plane conductor disposed on the bottom surface of said bottom substrate.

2. The UAV of claim 1 wherein the patch antenna element is positioned on the UAV at a location based on one or more of: a location of a control station, an intended UAV travel direction, locations of other antenna systems to prevent self-interference, location to reduce detection by enemy radar.

3. The UAV of claim 1 wherein the outer surface comprises a recess having dimensions configured to receive the patch antenna element such that the patch antenna element is conformally integrated with the outer surface.

4. The UAV of claim 1 wherein the first and bottom substrates comprise a polytetrafluoroethylene (PTFE) material.

5. The UAV of claim 1 wherein the intermediate substrate comprises a magneto-dielectric material.

6. The UAV of claim 1 wherein: the first substrate has a thickness of about 0.105 inches; the bottom substrate has a thickness of about 0.105 inches; the intermediate substrate has a thickness of about 0.040 inches; and the ground plane has a thickness of about 0.0014 inches.

7. The UAV of claim 1 wherein the patch conductor comprises an array of RF antenna elements.

8. The UAV of claim 1 wherein the patch conductor comprises a single RF antenna element.

9. The UAV of claim 1 further comprising a feed circuit coupled to the patch antennal element.

10. The UAV of claim 1 wherein the feed circuit is a coaxial cable.

11. The UAV of claim 1 further comprising an interface configured to conformally dispose the patch antenna element on the outer surface.

12. The UAV of claim 1 wherein the patch antenna element is configured to form a datalink with a control station.

13. The UAV of claim 1 wherein the control station is a ground-based vehicle or platform and/or an aerial vehicle or platform.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The foregoing and other objects, features and advantages will be apparent from the following more particular description of the embodiments, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the embodiments.

[0020] FIG. 1 is an isometric view of an unmanned aerial vehicle (UAV) having a conformal patch antenna with an intermediate magneto-dielectric substrate;

[0021] FIG. 2 illustrates a patch antenna having a patch stack-up which includes an intermediate magneto-dielectric substrate; and

[0022] FIG. 3 is an exploded view of a patch antenna intermediate which includes a magneto-dielectric substrate

DETAILED DESCRIPTION

[0023] Referring now to FIG. 1, an unmanned aerial vehicle (UAV) 100 includes a fuselage 105 to which a rotor 115 is coupled and on which a patch antenna 110 is conformally disposed. Although the rotor 115 is illustrated as being coupled to a nose of the UAV, a skilled artisan understands that a rotor can be positioned anywhere on the UAV to provide lift and that more than one rotor may be coupled to the fuselage 105. Furthermore, the UAV may include one or more rotors.

[0024] Patch antenna 110 includes at least one dielectric layer corresponding to a magneto-dielectric substrate disposed between a first dielectric having one or more antenna elements disposed on a surface thereof and a bottom dielectric having an antenna ground plane disposed on a surface thereof. Thus, the magneto-dielectric substrate corresponds to an intermediate layer in a patch antenna stack-up. An illustrative patch antenna which may be the same as or similar to patch antenna 110 will be described in detail in conjunction with FIGS. 2 and 3 below. Suffice it here to say that by utilizing a magneto-dielectric substrate patch antenna 110 is provided having bandwidth and gain characteristics which are improved relative to a conventional patch antenna having the same size, shape, thickness and number of antenna elements.

[0025] The fuselage 105 can include a recess (not shown) that has dimensions configured to receive the patch antenna element 110 such that the patch antenna element 110 is conformally integrated with the fuselage's outer surface. The patch antenna element 110 can be positioned anywhere on the outer surface of the fuselage 105. In some examples, the patch antenna element 110 is positioned on the UAV at a location based on a location of, e.g., a control station and/or an intended UAV travel direction. In further embodiments, the location is selected to prevent self-interference with other antenna systems, e.g., instance Telemetry, on the UAV. Additionally, the location can be selected to reduce detection by enemy radar (e.g., reduce radar cross section).

[0026] The patch antenna element 110 can be configured to form a datalink with a control station (not shown). For example, the patch antenna element can be coupled to a datalink receiver (not shown) disposed in the UAV to provide datalink communications in the ultrahigh frequency (UHF) range or very high frequency (VHF) range between the datalink receiver and the control station. The control station can be a ground-based vehicle or platform and/or an aerial vehicle or platform. The control station can include a controller that comprises circuitry to provide instructions to the UAV via the datalink. The instructions can be used to control the UAV.

[0027] In embodiments utilized for datalink communications, the patch antenna element 110 can achieve a frequency bandwidth that is about 12-13 MHz. In other embodiments, the patch antenna element 110 can have a 2:1 Voltage Standing Wave Ratio (VSWR) bandwidth, e.g., extending over frequency range of about 467 MHz to about 479 MHz. Additionally, the patch antenna element 110 can have a gain greater than 0 dB. Due to the higher gain, the patch antenna element 110 can form datalink communications with the control station at an increased range. Further, the patch antenna element 110 achieve a low VSWR over a broad frequency band.

[0028] The patch antenna element 110 can achieve geometries (e.g. shapes such as and regular or irregular shapes including but not limited to rectangular, square, oval or circular shapes) that enable the patch antenna to be conformally disposed on any airframe regardless of the airframe's form factor. Additionally, the patch antenna element 110 have a thickness size which is less than the thickness of conventional patch antennas having the same antenna characteristics.

[0029] Referring now to FIG. 2 is an isometric view of a patch antenna 210 which may be the same as or similar to patch antenna 110 described above in conjunction with FIG. 1. Patch antenna 210 is provided from a patch antenna stack-up comprising a top substrate 245, a patch conductor or patch element 211 (e.g., the patch conductor 311 of FIG. 3), an intermediate magneto-dielectric substrate 240, a bottom substrate 235, and a ground plane 230. The patch conductor is disposed on a first surface 246a of the top substrate 245. The intermediate magneto-dielectric substrate 240 is disposed on a second surface 246b of the top substrate 245 via a first intermediate substrate surface 241a. The bottom substrate 235 has a first bottom substrate surface 236a which is disposed on a second intermediate substrate surface 241b of the intermediate magneto-dielectric substrate 240. The ground plane 230 is disposed on a second bottom substrate surface 236b of the bottom substrate 235.

[0030] An adhesive 225 can be attached to the ground plane 230 to enable the patch antenna element 210 to be conformally disposed on a fuselage of a UAV (e.g., the fuselage 105 of FIG. 1). Although, in FIG. 2, the adhesive 225 is illustrated as a double-sided tape, a skilled artisan understands that any adhesive or mechanical fastener (e.g., screws, etc.) can be used to conformally dispose the antenna element onto a surface of a UAV.

[0031] A feed circuit 220 can be coupled to the patch antenna element 210. Although, in FIG. 2, the feed circuit is illustrated as a coaxial transmission line (e.g. a coaxial cable), one of ordinary skill in the art will appreciate that any known or yet to be known feed circuit for use with patch antennas can be used to couple RF signals to/from the patch antenna 210.

[0032] In embodiments for operation in the frequency range of about 467 MHz to about 479 MHz and having a bandwidth characteristic of about 12 MHz and a gain characteristic of about 0 dBi, patch antenna 210 can be provided having an overall thickness of or about 0.25 inches. The top substrate 245 can have a thickness of or about 0.105 inches. The intermediate magneto-dielectric substrate 240 can have a thickness of or about 0.040 inches. The bottom substrate 235 can have a thickness of or about 0.105 inches. The ground plane 230 can have a thickness of or about 0.0014 inches.

[0033] A skilled artisan understands from the teachings herein that a thickness of the antenna element 210 can be adjusted to achieve enhanced bandwidth while maintaining high gain.

[0034] The top substrate 245 can comprise a polytetrafluoroethylene (PTFE) material. The intermediate substrate 240 can comprise a magneto-dielectric material. The bottom substrate 235 can comprise a polytetrafluoroethylene (PTFE) material. The ground plane 230 can comprise one or more of a copper, gold plated, or similar material.

[0035] The antenna element 210 can have low weight characteristics and, thus flight performance of the UAV is not substantively affected by the antenna element 210. The weight of the antenna element 210 can be a quarter of conventional patch antenna elements.

[0036] Referring now FIG. 3, a patch antenna 310 which may be the same as or similar to patch antennas 110, 210 of FIGS. 1 and 2, is configured to be disposed on a UAV (e.g. UAV 100) so as to be conformal to an outer surface of an unmanned aerial vehicle (UAV). The patch antenna is provided from a patch antenna stack-up 313. The stack-up 313 comprises a first substrate 345, a patch conductor 310, an intermediate magneto-dielectric substrate 340, a second substrate 335, and a ground plane 330.

[0037] The patch conductor 311 is disposed on a top surface of the first substrate 345. The patch conductor 311 can comprise an array of RF antenna elements 312a-N. In other examples, the patch conductor 311 can comprise a single RF antenna element. The patch conductor 311 can have a thickness between about 0.0007 inches to about 0.0028 inches. The patch conductor may be provided from any material which is conductive to RF signals in a desired RF operating range of the patch antenna (e.g. an electrical conductor such as, but not limited to, copper may be used).

[0038] Comprise, include, and/or plural forms of each are open ended and include the listed parts and can include additional parts that are not listed. And/or is open ended and includes one or more of the listed parts and combinations of the listed parts.

[0039] One skilled in the art will realize that the concepts described herein may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting of the invention described herein. Scope of the invention is thus indicated by the appended claims, rather than by the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.