Session
Technical Session 8: Advanced Technologies II
Location
Utah State University, Logan, UT
Abstract
Electronically steerable antennas, that are compact, thin, light and contain no mechanical parts, are being more and more used for satcom applications on the ground, notably owing to the fast development of mega constellations; yet their use is still very limited on board. Indeed, all designs up to date rely on the same old concept, phased arrays, namely, a large number of sources that are phased matched to point in various directions. These can be passive, in the sense that a common feed is used to radiate through many radiators, or active in which case each tiny emitter contains its own source of waves. While the former are relatively simpler and less energy greedy, they are very dissipative and hence of poor efficiency. The latter, on the contrary, often offer good performances, yet they are extremely costly and require huge amounts of electrical power to operate, the vast majority of which is dissipated into heat. In a nutshell, both active and passive phased arrays have tremendous problems when it comes to space applications.
Here we introduce the concept of the reconfigurable leaky cavity antenna, that stems on a radically different approach to beamforming. It uses a thin leaky cavity that, when excited by one or several feeds, can establish any desired wavefield corresponding to any desired radiation pattern. To achieve this, the cavity is reconfigured in real time by an electronically reconfigurable intelligent surface (metasurface). The latter controls the reflections of the waves inside the cavity, acting as a software-controlled set of boundary conditions. Being based on discrete components, the antenna maintains the cost-efficiency, robustness and power sobriety of the simplest passive phased arrays, with a power needed for beamforming as low as a few tens of watts at Ku or Ka. In the meantime, since the control is solely based on electronics, it achieves the performances of active phased arrays at the same time, for instance in terms of gain or switching speeds. With its high performances and low complexity, our concept paves the way to the deployment of electronically steerable antennas on board.
Further, since the beamforming does not result from the synchronization of many elementary sources, but rather on the shaping of a wavefield inside a cavity, our concept is standard or protocol agnostic. Moreover, it is able to support multiple frequency bands, and to emit multiple beams, at different frequencies and with different polarization.
A Wave Physics Approach to Electronically Steerable Antennas
Utah State University, Logan, UT
Electronically steerable antennas, that are compact, thin, light and contain no mechanical parts, are being more and more used for satcom applications on the ground, notably owing to the fast development of mega constellations; yet their use is still very limited on board. Indeed, all designs up to date rely on the same old concept, phased arrays, namely, a large number of sources that are phased matched to point in various directions. These can be passive, in the sense that a common feed is used to radiate through many radiators, or active in which case each tiny emitter contains its own source of waves. While the former are relatively simpler and less energy greedy, they are very dissipative and hence of poor efficiency. The latter, on the contrary, often offer good performances, yet they are extremely costly and require huge amounts of electrical power to operate, the vast majority of which is dissipated into heat. In a nutshell, both active and passive phased arrays have tremendous problems when it comes to space applications.
Here we introduce the concept of the reconfigurable leaky cavity antenna, that stems on a radically different approach to beamforming. It uses a thin leaky cavity that, when excited by one or several feeds, can establish any desired wavefield corresponding to any desired radiation pattern. To achieve this, the cavity is reconfigured in real time by an electronically reconfigurable intelligent surface (metasurface). The latter controls the reflections of the waves inside the cavity, acting as a software-controlled set of boundary conditions. Being based on discrete components, the antenna maintains the cost-efficiency, robustness and power sobriety of the simplest passive phased arrays, with a power needed for beamforming as low as a few tens of watts at Ku or Ka. In the meantime, since the control is solely based on electronics, it achieves the performances of active phased arrays at the same time, for instance in terms of gain or switching speeds. With its high performances and low complexity, our concept paves the way to the deployment of electronically steerable antennas on board.
Further, since the beamforming does not result from the synchronization of many elementary sources, but rather on the shaping of a wavefield inside a cavity, our concept is standard or protocol agnostic. Moreover, it is able to support multiple frequency bands, and to emit multiple beams, at different frequencies and with different polarization.
