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A 94 GHZ IMAGING ARRAY USING SLOT LINE RADIATORS
A planar endfire slotted-line antenna structure has been experimentally investigated. It was found that the H-plane beamwidths are basically dependent upon the substrate properties, whereas the E-plane beamwidths are more strongly a function of the slot's shape and size. It is shown that these antennas produce symmetrical E- and H-plane beamwidths while following Zucker's standard traveling-wave antenna beamwidth curves over some range of antenna normalized length. An empirically derived design formula for effective substrate thickness is shown to predict this range for linearly tapered slotted-line antennas.^ These antennas were subsequently arrayed and mutual impedance data measured with a vector network analyzer and infered from their measured single element and arrayed radiation patterns. It was found that the antennas could be spaced up to 1.5 wavelengths before mutual impedance could be measured using the vector network analyzer and up to 2.5 wavelengths before any change in the radiation patterns were found.^ Arrays of these LTSA antennas were constructed for operation at 94 GHz with inter-element spacings of 1.5 and 2.5 wavelengths and evaluated with a Cassegrain reflector antenna. The experimental imaging properties of these arrays were presented and imaging theory was discussed. It was shown that a minimum spacing of elements is necessary for exact reconstruction of a sampled image in a diffraction limited system. Because these LTSA elements employ the traveling-wave mechanism of radiation, they can be spaced two times closer than a conical feed horn of comparable beamwidth. An LTSA array with 2.0 wavelength inter-element spacing would be capable of exact image reconstruction when used in a complex E-field sampling system. ^
Engineering, Electronics and Electrical
KORZENIOWSKI, THOMAS LEO, "A 94 GHZ IMAGING ARRAY USING SLOT LINE RADIATORS" (1985). Doctoral Dissertations Available from Proquest. AAI8602654.