Abstract. We describe the equipment, observational method and reduction procedure of an absolutely calibrated radio continuum survey of the South Celestial Hemisphere at a frequency of 1420 MHz. These observations cover the area 0 h ≤ RA ≤ 24 h for declinations less than −10• . The sensitivity is about 50 mK TB (full beam brightness) and the angular resolution (HP BW ) is 35. 4, which matches the existing northern sky survey at the same frequency.

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This paper describes the design and construction of a crossed slot antenna array to be applied to an Incoherent Scatter Radar for measuring parameters of the Ionosphere. The slot antenna was designed and optimized with electromagnetic simulation software. An analysis of the characteristic modes of the elementary antenna of the array is performed, in order to obtain a physical understanding of the radiating behavior. A prototype of a linear crossed-slot antenna array has been constructed and measured, as an intermediate step for the development of a two-dimensional array.

In this paper, a modal analysis of a slot inserted in a finite ground plane is presented, giving physical understanding of its radiation behavior and the interaction effects between the slot and the plane. The Theory of Characteristic Modes (TCM) reveals that for the case of slotted planar antennas the modes of the slot do not appear as independent modes. This paper also shows that the slot resonance fixes the upper frequency of the excited modes in the combined structure formed by the slot and the finite plate. Moreover, the modal analysis demonstrates that the radiation pattern stability and the radiation bandwidth of the slot antenna are directly related with the size of the finite ground plane. The conclusions reached with the application of TCM can be employed to optimize the geometry and the size of the finite plate in order to prevent the excitation of non-desired modes.