Abstract: The disclosed invention mounts transmitting and receiving electrical coils (52, 54) within channels or chambers (48, 50) formed by the notched ends of magnets (24, 28) closest to the metallic structure under test (40) where said magnets (24, 28) are arranged to form annular arrays (20, 22) of an electromagnetic acoustic transducer (EMAT) pair applicable in non-destructive testing. The detection of one or more electromagnetically-induced resonant frequencies at shifted locations indicates the presence of one or more flaws (58, 60) in the metallic structure under test (40). The novel recessed mounting of the coils provided by the channels or chambers (48, 50) substantially reduces the observed electrical cross-talk between coils (52, 54) over the prior art and reduces the likelihood of the coils (52, 54) making contact with the subject metallic structure under test (40) as it is in longitudinal motion relative to the coils (52, 54).

Abstract: Data compression method, system, and program code for compressing antenna pattern data generated by measuring the complex voltage derived from the interaction of a RF waveform and a sensing element are disclosed. The antenna pattern data are modeled with a plurality of infinitesimal antenna elements, each element defined in terms of a distinct position, orientation, and polarization. An analytical expression for the interaction between the plurality of infinitesimal antenna elements and an impinging waveform yields a plurality of expressions for a theoretical voltage. The plurality of infinitesimal antenna elements constitute a mathematical basis set from which a weighted linear combination is constructed. The value of the weights are determined by equating the complex voltage representing the antenna pattern data with the theoretical voltage representing the plurality of weighted infinitesimal antenna elements.

Abstract: The present invention provides processes and apparatus for selectively dissolving and removing unwanted solid and semi-solid materials and the like, within a highly localized region utilizing ultra-high energy acoustical waves having a frequency in the range above 50 MHz, for example from about 50 MHz to about 100 GHz. The invention apparatus includes a piezoelectric transducer that is modified to increase the amplitude of acoustical waves of a given frequency without increase in power to the system. The invention and apparatus have important applications in surgical procedures for the treatment of atherosclerotic plaque, prostate disorders, cancers, orthopedic and cosmetic surgery, various types of orthopedic surgery, including atheroscopic surgery, and the like. The present invention is also useful in a wide variety of non-surgical applications, including industrial processes, wherein materials are desired to be selectively removed in a very localized region.

Abstract: A carrier structure apparatus for mounting conformal antenna elements to a non-planar mounting surface as part of an antenna array of an airborne vehicle or ground-based system also comprising a seeker section, fairing and guidance processing system. The carrier structure is a rigid and conductive apparatus that is made to conform to the geometric configuration of both the antenna element as well as the mounting surface. The conformal antenna is rigidly mounted to the carrier structure, which is in turn removably affixed to the non-planar mounting surface. With the carrier structure, each antenna element of the array may be individually tested and replaced prior to and after installation in array.

Abstract: A timing and control method and apparatus (111) for performing precise range rate aiding includes a range gate delay means (114) for generating an estimate of the range gate delay (135) each pulse repetition interval as a function of the initial range (134) and velocity (133) provided by a processor (104). The range gate delay (135) is converted into a coarse delay (138) defining the integral number of clock cycles preceding the range gate, and a fine delay (139) for positioning a range gate to within a fraction of a clock cycle. Fine temporal control is achieved using programmable delay lines (117) and (118), which retard various control signals, including the system clock signal (131), in accordance with the fine delay (139). A modified signal (126) then drives a counter means (119) which outputs a signal (128) that defines an analog-to-digital sampling window beginning at the elapse of the range gate delay (135).