Flexline wrap antenna for projectile
A projectile circuitry assembly for use in projectiles comprising a chassis defining a generally cylindrical a main body portion and further defining an interior cavity for containing one or more projectile components and further defining an antenna aperture through the body portion to expose the interior cavity. In various embodiments the projectile circuitry assembly comprises a plurality of circuit boards and a wrap antenna, the plurality of circuit boards and wrap antenna interconnected via an integrated flex-line to define a single unitary device without the use of a connector, the wrap antenna comprising one or more antenna elements defined on a flexible antenna substrate layer, wherein the plurality of circuit boards are positioned in the interior cavity and the wrap antenna is threaded through the antenna aperture and wrapped circumferentially about an exterior of the cylindrical wall of the body portion.
1. A projectile having a nose portion with a forward tip, a body portion, a tail portion, and a central axis, the projectile comprising:
a chassis extending from the tail portion to the nose portion, the chassis defining a generally cylindrical wall of the body portion and further defining an interior cavity within the projectile and further defining an antenna aperture through the cylindrical wall of the body portion;
a projectile circuitry assembly comprising one or more circuit boards and a wrap antenna, the one or more circuit boards and the wrap antenna interconnected via an integrated flex-line, the wrap antenna comprising one or more antenna elements that are defined on a flexible antenna substrate layer, wherein the one or more circuit boards are positioned in the interior cavity and at least a portion of the wrap antenna projects through the antenna aperture and is wrapped circumferentially about an exterior of the cylindrical wall of the body portion; and
a sealing material sealing the antenna aperture.
2. The projectile of claim 1 , wherein the projectile circuitry assembly comprises: a board ground layer, a board substrate layer, a first transition layer, a first flex-line substrate layer, a flex-line signal layer, a second flex-line substrate layer, a second transition layer, an antenna substrate layer, and an antenna signal layer.
3. The projectile of claim 2 , wherein the projectile circuitry assembly is a flex-line board comprising: a circuit board portion, a flex-line portion, and an antenna portion, the circuit board portion defined by the board ground layer, the board substrate layer, and the first transition layer, the flex-line portion defined by the first transition layer, the first and second substrate layers, the flex-line signal layer, and the second transition layer, and the antenna portion defined by the second transition layer, the antenna substrate layer, and the antenna signal layer.
4. The projectile of claim 1 , wherein the projectile circuitry assembly is a flex-line board comprising: a board ground layer, a board substrate layer, a first transition layer, a first substrate layer, a second substrate layer, a signal layer, and a ground layer.
5. The projectile of claim 4 , wherein the projectile circuitry assembly comprises a circuit board portion and a signal portion, the circuit board portion defined by at least a board ground layer, a board substrate layer, and the first transition layer, and the signal portion defined by the first substrate layer, second substrate layer, the signal layer, the ground layer, and the first transition layer.
6. The projectile of claim 5 , wherein the signal portion, is configurable to function as either a flex-line or an antenna.
7. The projectile of claim 1 , wherein the generally cylindrical wall of the body portion defines an antenna recess in the main body portion; and
wherein the antenna portion is mounted within the antenna recess such that the antenna portion partially fills the recess and leaves an unfilled portion between an exterior of the antenna recess and an exterior of the cylindrical wall.
8. The projectile of claim 1 , wherein the wrap antenna further comprises a protective cover.
9. The projectile of claim 1 , wherein the one or more circuit boards define an antenna circuitry portion, wherein the antenna circuitry portion includes one or more projectile control circuitry comprising sensing components, processing components, baseband processing components, and fuzing.
10. The projectile of claim 1 , wherein the sealing material comprises an epoxy.
11. The projectile of claim 1 , wherein the sealing material comprises a solder bead.
12. The projectile of claim 11 , wherein the solder bead encloses the one or more circuit boards in the projectile interior and isolates the one or more circuit boards from exterior electromagnetic fields.
13. A method of assembling a projectile and a projectile circuitry assembly, the projectile comprising a chassis extending from a tail portion to a nose portion, the chassis defining a generally cylindrical wall of a main body portion and further defining an interior cavity within the projectile for containing one or more projectile components and further defining an antenna aperture slot extending axially through the cylindrical wall of the body portion exposing the interior cavity, and the projectile circuitry assembly comprising one or more circuit boards and a wrap antenna, the one or more circuit boards and the wrap antenna interconnected via an integrated flex-line to define a unitary device, the wrap antenna comprising one or more antenna elements that are defined on a flexible antenna substrate layer, wherein the method comprises:
configuring the projectile circuitry assembly into a compact state such that the plurality of circuit boards are insertable into the interior cavity;
disposing the antenna to extend through the antenna aperture slot;
wrapping the antenna of the projectile circuitry assembly about the exterior of the chassis; and
sealing the antenna aperture slot with a sealing material.
14. The method of claim 13 , wherein in the compact state the integrated flex-line is folded to arrange the one or more circuit boards together in a stack with the antenna portion wrapped around the one or more circuit boards.
15. The method of claim 13 , wherein the generally cylindrical wall of the body portion defines an antenna recess in the main body portion; and
wherein the antenna is wrapped within the antenna recess such that the antenna portion partially fills the recess and leaves an unfilled portion between an exterior of the antenna recess and an exterior of the cylindrical wall.
16. The method of claim 13 , wherein the sealing material comprises an epoxy.
17. The method of claim 13 , wherein the sealing material comprises a solder bead.
18. The method of claim 17 , wherein the solder bead encloses the one or more circuit boards in the projectile interior and isolates the one or more circuit boards from exterior electromagnetic fields.
19. The method of claim 13 , wherein the antenna aperture slot defines a forward opening at the opening into the interior cavity.
20. The method of claim 19 , wherein the wrap antenna is inserted at the forward opening of the antenna aperture slot.