In this paper, we propose the design of a reconfigurable metasurface filter incorporating phase change materials (PCMs). This filter is part of a novel spaceborne spectrometer concept for atmospheric monitoring. The metasurface filter consists of PCMs pillars embedded in a diamond matrix. The combination of shape and material properties results in resonances that give rise to specific spectral filtering functions. The optical properties of PCMs, and hence the transmission function, change when stimulated with a pulsed laser. In combination with a compressive sensing (CS) algorithm, a limited number of measurements with a single metasurface results in precise reconstructions of the Earth's atmospheric spectrum. ... Read more

In this paper, we present the characterization of a Ku-band connected-dipole array for mobile Satcom application. The prototype array consists of 2×256 dipole radiators arranged in a square grid, to form 16×16 dual-polarized cells. It has been designed to operate over a wideband ranging from 10.7 to 14.5 GHz (30%), accommodating in a single antenna both the transmit (14.0 to 14.5 GHz) and the receive (10.70 to 12.75 GHz) bands for the application. The array has been characterized in terms of active reflection (AR) and radiation patterns. Dedicated test support equipment (TSE) has been developed and used to test the array radiation characteristics. Over the frequency range of operation, the array maintains good matching (ensuring system gain to noise temperature better than 8 dB/K) and good radiation performance while scanning as far as 60 degrees in all the azimuth planes. The cross-polarization suppression is better than 15 dB within most of the scan range and reaches 10 dB for the extreme scan angles in the diagonal plane. ... Read more

This work reports on the development and performance of a doubly-polarized array of connected dipoles for in-flight entertainment. The array is designed to simultaneously operate in the uplink and the downlink bands, with an overall bandwidth of about 30%, from 10.7 to 14.5 GHz. The array prototype comprises 16×16 elements in each polarization for a total of 512 elements. The use of a loop-shaped transformer in the feed lines and a wide angle impedance matching (WAIM) sheet allows to achieve low cross-polarization and sufficiently good matching for scanning up to ±60° in elevation for every azimuth plane. ... Read more

In this work we describe an effective strategy for the avoidance of common-mode resonances excited in a printed array of loaded dipoles with inherent filtering properties (filtenna). Previous works demonstrated that, for E-plane scanning, such resonances occur due to the unbalanced excitation of the dipoles. The present approach is based on the use of an X-band hybrid-ring connected to the filtenna structure. A design with operational bandwidth spanning from 8.5 to 10.5 GHz is presented and validated with simulations. ... Read more