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A new strategy to obtaining polarization-agile array antennas was discussed. It makes use of the interleaving of sparse (complementary) sub-arrays characterized by mutually orthogonal, linear polarizations. The validity of this approach was demonstrated by examining two examples of arrays designed for obtaining adjustable linearly-polarized waves. The(More)
The design aspects concerning the sparse array antennas are discussed. Commonly, the beamwidth, the side-lobes level and the gain are the relevant features in antenna design procedures. These parameters are evaluated for different sparse topologies and generalised design relations are provided. The capabilities of sparse architectures are evaluated by(More)
A consistent strategy for the design of finite array antennas consisting of differently sized radiating elements is discussed. In view of increasing the total bandwidth of the antenna system, while maintaining a low mutual coupling between the elementary radiators, sparse subarrays, operating at adjacent frequency ranges, are interleaved on a common(More)
An effective method for estimating the mutual coupling in finite, arbitrary arrays of rectangular waveguide apertures is discussed. It relies on evaluating the admittance matrix relating rectangular waveguide modes, its entries being computed by means of an interpolation strategy with demonstrated accuracy. The method's strength is demonstrated by means of(More)
For accurate estimation of AOA of multiple sources an antenna array can be used. In this paper a comparison between the directions finding capability of three array geometries circular array, uniform- and non-uniform Y-shaped array are presented. The center frequency is 2.25 GHz with a bandwidth of 100 MHz. The antenna element is the skirt monopole. The(More)
A new family of structures launching the fundamental mode in rectangular waveguides is proposed. Individual or stacked cavity-backed patch antennas radiate into a rectangular waveguide, providing a good matching with a coaxial input over a wide frequency range. The configuration results in a very compact, colinear transition from a standard coaxial(More)
A design technique for sparse array configurations consisting of dielectric-filled, open-ended waveguide antennas is discussed. The position of the elements in the thinned array are determined by applying a genetic algorithm that searches for configurations with the lowest side-lobe level. By employing as design parameter the relative inter-element spacing,(More)
A solution to designing multifunction array antennas is discussed. Distinct system functions performed at separate frequency ranges are associated to sparse sub-arrays that are interleaved in a shared aperture configuration. The sparse architectures are designed using a combinatorial method that ensures an acceptable behavior in the side-lobes region in(More)
The design of a matching circuit, consisting of an air gap in the transmission line that feeds a dielectric-filled, open-ended waveguide antenna is discussed. The Mode Matching Method is employed for assembling the Generalized Admittance Matrix of a matching circuit (this matrix yielding, in turn, an equivalent, ll lumped elements circuit) and for(More)
A novel structure for launching the fundamental mode in rectangular waveguides is proposed. The geometry consists of a cavity–backed circluar patch radiating into a rectangular waveguide. The matching properties of the proposed component are comparable with the ones of the classically used L–shaped loop end–launcher. The structure results in a very compact,(More)