Based on the existing mathematical formalisms of radar polarimetry, it is necessary to perform accurate and diversified polarimetric measurements in the real world to thoroughly investigate signature definition, identification, and classification of radar targets. For this study the Delft Atmospheric Research Radar (DARR) is used. This ground-based polarimetric FM-CW radar operates in the S-ban...

We report here a broadband reflector based on a two cross-stacked grating structure. This type of broadband reflector is polarization-independent, with ~100% reflectance over a designed spectral range of 1.4 to 1.6 μm. The reflection phase differences between TE and TM polarizations remain almost a constant value of 1.2π over the same high reflection spectral range. The reflector performance to...

A new and compact fluorescence biosensor is constructed. The distinguished feature of this setup is the use of an ellipsoidal reflector as an optical collector of the fluorescence light. A traditional collecting lens with numerical aperture of 0.5 can only collect a few percent of the available signal, while the incorporation of the ellipsoidal reflector enables the apparatus to provide a signa...

We propose an elastic scalar imaging condition that corrects for the polarity change; however, this imaging condition requires additional prior information which may not be known accurately, or may suffer from interference of waves propagating from opposite sides of a reflector. Using incorrect Pand S-mode velocities causes reflectors in migrated PP, PS, and SP images to be shifted from their t...

With the recent advent on communication and satellite industry, there is a great need for efficient Reflector antennas systems, therefore more powerful techniques are requested for analysis and design of new reflector antennas in a quick and accurate manner. This work aim first to introduce wavelet-based moment method in 3D, as a recent and powerful numerical technique, which can be applied on ...

The development history of Umkehrwalze Dora (UKWD), Enigma's pluggable reflector, is presented from the first ideas in the mid-1920s to the last development plans and its actual usage in 1945. An Enigma message in three parts, enciphered with UKWD and intercepted by the British on 11 March 1945, is shown. The successful recovery of the key of this message is described. Modern computer-based cry...

Studies conducted by the Cambridge Radio Observatory Committee during the past two years show that a large steerable telescope can be constructed at lower cost and with higher precision if the antenna is protected from the environment by a radome. These studies also indicate that the extremely high pointing precision (10 arc-sec) needed to make effective use of a large aperture at wavelengths a...