An Efficient Multi-Beam Array Architecture for L-Band Secondary Surveillance Radars

In this paper, the design and fabrication of a large array antenna with three required, Sum, Difference and Control beams for a monopulse Secondary Surveillance Radar (SSR) is presented. A special array element, which is a high gain dual dipole structure, is designed and tested. This element has 9.6 dB gain in 1060 MHz and does not need any balun. The main challenge of extracting three beams out of one beam feeding networks (BFN) has been resolved efficiently by maximum integration of all three in one network, reducing the number of required modules to one half. The complete 33-element array, working in 1030 MHz and 1090 MHz is designed based on the Taylor array factor. The complex feed network of this 6-meter long array has successfully been synthesized as modular as possible. Sum pattern was designed for 2.7o azimuth beam width and -20 dB side lobe level and Diff pattern with a deep null in the boresight of the Sum pattern. The Ctrl beam was also designed in order to cover the Sum beam except in the direction of the main lobe

Understanding the role of the hydrogen bond donor of the deep eutectic solvents in the formation of the aqueous biphasic systems

Deep eutectic solvents (DES) have been proposed as phase-forming compounds of aqueous biphasic systems (ABS). However, due to DES nature and the high water content of the ABS, their nature and behavior remains controversial. To foster the understanding of DES-based ABS, the present work uses the relative hydrophilicity of the hydrogen bond donor (HBD) as a descriptor to clarify its role on ABS for- mation and phase properties. Dipotassium phosphate (K2HPO4)-based ABS phase diagrams composed of cholinium chloride ([N111(2OH)]Cl), as hydrogen bond acceptor (HBA), and several HBD (alcohols and sugars) were compared in molality units and the saturation solubility point for each binodal curve determined. The results here reported establish the HBD role as function of its relative hydrophilicity: very hydrophilic HBD act only as an adjuvant in the formation of ABS; HBD of intermediate hydrophilicity influence the ABS formation; while the most hydrophobic HBD tend to form organic-aqueous two-phase systems, where the HBA acts as an adjuvant to the system.publishe