Systems and methods for efficient coupling to low-loss eigenmodes of a spherical waveguide bounded by the Earth's surface and its ionosphere are disclosed. One or more eigenmodes of the Earth-ionosphere waveguide may be computed based on a mathematical model incorporating electrical properties of the terrestrial surface and plasma physics of the ionospheric layer. An array of electrically-connected waveguide-coupling elements may be configured for coupling to the one or more eigenmodes. By adjusting relative phases and/or amplitudes of the waveguide-coupler elements, as well as frequencies, the electrical size of the array may be made much larger than its physical size, and substantial electromagnetic energy may be targeted to preferentially excite the one or more eigenmodes. The adjustments may also account or compensate for non-homogeneous propagation properties of the ionosphere, and help reduce ohmic losses in the ionosphere.

A contactless datalink for transmission of data between a rotatable part and a stationary part, including a dielectric waveguide split into two sections. A first dielectric waveguide section is at the rotatable part and a second dielectric waveguide section is at the stationary part. The first dielectric waveguide section is coupled to a transmitter and the second dielectric waveguide section is coupled to a receiver.

In accordance with one or more embodiments, a dielectric coupler includes a neck portion configured to receive a first electromagnetic wave from a hollow waveguide. A flared portion is configured to generate, responsive to the first electromagnetic wave, a second electromagnetic wave along a surface of a transmission medium, wherein the flared portion at least partially surrounds the transmission medium, wherein the second electromagnetic wave propagates along the surface of the transmission medium without requiring an electrical return path. A tapered portion is configured to interface the neck portion to the flared portion.

In accordance with one or more embodiments, a dielectric coupler includes a neck portion configured to receive a first electromagnetic wave from a hollow waveguide. A flared portion is configured to generate, responsive to the first electromagnetic wave, a second electromagnetic wave along a surface of a transmission medium, wherein the flared portion at least partially surrounds the transmission medium, wherein the second electromagnetic wave propagates along the surface of the transmission medium without requiring an electrical return path. A tapered portion is configured to interface the neck portion to the flared portion.

Systems and methods for efficient coupling to low-loss eigenmodes of a spherical waveguide bounded by the Earth's surface and its ionosphere are disclosed. One or more eigenmodes of the Earth-ionosphere waveguide may be computed based on a mathematical model incorporating electrical properties of the terrestrial surface and plasma physics of the ionospheric layer. An array of electrically-connected waveguide-coupling elements may be configured for coupling to the one or more eigenmodes. By adjusting relative phases and/or amplitudes of the waveguide-coupler elements, as well as frequencies, the electrical size of the array may be made much larger than its physical size, and substantial electromagnetic energy may be targeted to preferentially excite the one or more eigenmodes. The adjustments may also account or compensate for non-homogeneous propagation properties of the ionosphere, and help reduce ohmic losses in the ionosphere.

A device is provided that includes a first waveguide configured to guide propagation of RF waves inside the first waveguide. A first side of the first waveguide is configured to emit an evanescent field associated with the propagation of the RF waves inside the first waveguide. The device also includes a second waveguide having a second side positioned within a predetermined distance to the first side of the first waveguide. The second waveguide is configured to guide propagation, inside the second waveguide, of induced RF waves associated with the evanescent field from the first waveguide. The device also includes a first probe coupled to the first waveguide and configured to emit the RF waves for propagation inside the first waveguide. The device also includes a second probe coupled to the second waveguide and configured to receive induced RF waves propagating inside the second waveguide.

This antenna includes a first part, a second part rotatably mounted about a first axis, and a rotary joint arranged between the first and second parts, the second part including a radiating source and a reflection assembly having a reflector defining a reflector top, a focus, and a second axis passing through the reflector top and the focus, the rotary joint being able to transmit electromagnetic signals between the first and second parts via at least one transmission channel, and the first and second parts being so arranged that in any position of the second part and the reflection unit, the first axis is perpendicular to the second axis.

A rotary joint including a stator intended to be fastened on a first part of the antenna and defining a transmission surface, and a rotor intended to be fastened on a second part of the antenna and defining a transmission surface, wherein one of the transmission surfaces includes primary means for delimiting electromagnetic signals and the other includes complementary means for delimiting electromagnetic signals; the rotor being mounted rotating relative to the stator such that at least part of the transmission surface of the rotor is positioned across from at least part of the transmission surface of the stator, the facing parts forming at least one transmission path between them for the electromagnetic signals delimited by the primary and complementary delimiting means.

A system and method are disclosed for providing a bi-directional data communication link within a LIDAR assembly that has a stationary portion attached to an autonomous vehicle and a second portion rotatably connected to the stationary portion. The second portion may include one or more emitting/receiving devices (e.g., lasers) for detecting objects surrounding the autonomous vehicle. A first printed circuit board assembly (PCBA) having a first optical transceiver may be located within the stationary portion. A second PCBA having a second optical transceiver may be located within the second portion. A hollow shaft may be positioned so as to extend between the stationary portion and the second portion.

In accordance with one or more embodiments, a dielectric coupler includes a neck portion configured to receive a first electromagnetic wave from a hollow waveguide. A flared portion is configured to generate, responsive to the first electromagnetic wave, a second electromagnetic wave along a surface of a transmission medium, wherein the flared portion at least partially surrounds the transmission medium, wherein the second electromagnetic wave propagates along the surface of the transmission medium without requiring an electrical return path. A tapered portion is configured to interface the neck portion to the flared portion.