This paper focuses on the measurement of antenna radiation patterns when fully anechoic conditions are not available and, as consequence, some undesirable echoes are initially present in the measure. Two techniques are analyzed and compared, which -starting from data measured in the frequency domain -allow the echo contributions to be identified and the antenna radiation pattern to be retrieved...

We deal with the problem of the linearized and isotropic elastic inverse scattering by interfaces. We prove that the scattered P -parts or S-parts of the far field pattern, corresponding to all the incident plane waves of pressure or shear types, uniquely determine the obstacles for both the penetrable and impenetrable obstacles. In the analysis, we assume only the Lipschitz regularity of the i...

In this paper a novel biconical antenna geometry has been proposed that has directive radiation pattern, higher gain and enhanced front to back ratio. Wide band performance is another characteristic of this new antenna.

Consider the exterior boundary value problem (V* + k’) u = 0, in R, k > 0. u lr. = k where T is a smooth closed connected surface in Ip’, u exp(ik 1x1) Ixl-‘f(k, n) as Ix/ + co, n =x lx]-‘, f is called the radiation pattern. We prove that when h runs through any dense set in L’(r) the corresponding radiation pattern f(k, n) runs through a dense set in L*(S’) for any k > 0, where S* is the unit ...

This work examines the ability of a special type smart antenna array known as Switched Active Parasitic Antenna (SASPA) to produce directive and electronically steerable radiation pattern. The SASPA consists elements that are switchable between active parasitic states by using P-Intrinsic-N (PIN) diodes. element is supplied radio frequency while short-circuiting terminals an in results element....