Sector backward

There is considerable debate within the organic sector as to the rightness of selling to supermarkets. Most organic farmers would like their products to be sold in their local towns and not transported backwards and forwards across the country. They are also apprehensive about the power and ruthlessness of the supermarket buyers, who are not seen as being user-friendly. That said, the major multiples... 

A comparative analysis of the interwar scientific and technological institutions related to the chemical industry also confirms the pessimistic diagnosis of contemporary observers. The two modest initiatives, the Institute Quimico de Sarria and the Institut de Quimica Aplicada, reveal the backwardness of Spanish institutions. One cannot make the private sector alone responsible for Spain s low level. It seems much more as if the merely adaptive attitude of the companies was a rational response to the absence of a scientific and technological policy. There was not in Spain any institute like the Milano Politecnico, and there were no outstanding personalities. Looking at this key aspect of industrial progress, it is hard to believe that, had the Civil War not taken place, and had Spain entered World War II, the Spanish chemical industry would have emulated that of Italy. The scientific and technical deficit of Spain remains one of the more puzzling questions of Spanish economic history. 

Most readers will say no. They typically base their answer on well-documented facts about the most commonly used antennas such as a single dipole or monopole, the horn, the flat spiral, the corner reflector, the polyrod, the patch, the log periodic, the helical with a groundplane, and many more. These are all lacking in their ability to produce a low RCS over a broad frequency range when properly matched. Thus, we shall in this chapter instead concentrate on one of the few concepts that can truly produce invisibility in the backward sector, namely the large flat aperture in the form of an array backed by a groundplane and with uniform aperture illumination. The tapered case will also be discussed and it will be shown that also in that case, invisibility is conceptually compatible with 100% efficiency. 

Let us first examine the backward sector. If we assume that the load impedance Zl is conjugate-matched to the antenna impedance Z, all the energy incident upon this array with a groundplane will (as shown in Section 2.6.2) basically be absorbed. Thus, for this load condition the scattering pattern will simply be given by a number of low-level sidelobes due to the finiteness of the array. For an actual calculated example of what happened when Zl Z, see Section 5.3. 

The power scattered in the backward sector as a result of the tapered distribution can be absorbed if we work with arrays (see Section 2.13). However, most antennas with tapered aperture distribution are bad candidates for low RCS antennas. Homs, for example, always have a tapered aperture distribution because... 

The message is one of the increasing technical complexity of regulation, of proliferation of standards in the major purchasing sector of Defence, and of the relatively backward nature of other sectors. 

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