Abstract-This paper proposes an approximate space-time-frequency field representation for directive Ultra-wideband antennas useful to be introduced into a system-level evaluation tool. Based on the observation that the very near field collected on a plane close to the antenna exhibits a compact support, such a field is processed in the time domain by the two-dimensional Hermite transform. This approach permits to simultaneously express the antenna impulse response and the transfer function by semi-analytical formulas. The theory is demonstrated by numerical examples which highlights that good representations of complex antennas can be achieved by a small set of associate Hermite functions.
We introduce a new class of reflectarrays, namely, the aperiodic conformal reflectarrays, aimed at exploiting, as much as possible, the available degrees of freedom of the radiating structure, such as positions, orientations and characteristics of the radiating elements and the shape of the reflecting surface. A synthesis technique is outlined, properly dealing with key aspects such as the complexity of the employed radiative model, the algorithms exploited to achieve the final solution, the hardware adopted to run the synthesis code, and the constraints dictated by physical and manufacturing requirements. The potentialities of aperiodic conformal reflectarrays are discussed, also with the aid of a numerical example
A synthesis technique for reflectarray antennas is here proposed, aimed to allow a multi-frequency design of an antenna whose degrees of freedom are, apart from the standard ones, also the element positions and the reflecting surface shape. The approach is based on a proper multi-frequency formulation that allows to optimize the antenna behavior over a certain bandwidth
The results obtained in the frame of the ESA activity “Advanced Antenna Concepts For Aircraft In Flight Entertainment” are presented. The aim of the activity consists in designing an active antenna able to guarantee the Ku band link between an aircraft and a geostationary satellite in order to provide in flight entertainment services. The transmit-receive antenna generates a single narrow beam to be steered electronically in a half sphere remaining compliant with respect to stringent requirements in terms of pattern shape, polarization alignment, EIRP, G/T, and using customized electronic devices. At the same time, the proposed solution should be competitive in terms of cost and complexity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.