Preliminary Analysis of the Effects of the Ground Plane on the Element Patterns of SKA1-Low

Each station of the SKA1-Low radio telescope is composed by 256 dual-polarized log-periodic antennas deployed over a metallic ground plane with 42 m diameter. This station is usually modelled in EM simulators by considering an infinite ground plane, which drastically reduces the computational time. This contribution shows that a finite ground plane can bring to quite significant differences in some embedded element patterns with respect to the infinite ground plane case. Furthermore, we show the impact on the antenna pattern of different dielectric media surrounding the finite ground plane. For instance, at 50 MHz the maximum of the antenna gain decreases by 5% for the terrain with 10% moisture level

Electromagnetic modelling of the SKA-LOW AAVS2 prototype

The computational electromagnetic modelling of a large radio telescope prototype array for the Square Kilometer Array is described. The numerical models, using the Method of Moments, are characterised by a very large number of unknowns, requiring the use of fast solution methods and high performance computing platforms. Good agreement has been obtained between results obtained on two different commercial codes. Results for both embedded element patterns and the station beam are shown. The use of the computed embedded element patterns for array calibration is briefly addressed

Efficient electromagnetic characterization and optimization of a 1D reconfigurable periodic configuration in microstrip technology

Application of the Synthetic Function eXpansion (SFX) algorithm to the analysis of active, reconfigurable 1D structures is presented. The reference structure consists of a passive configuration of parallel patches periodically loading a microstrip line. The active counterpart is obtained by inserting a pair of 2 switches to the two ends of each patch. The matching and radiation characteristics of a 24-element arrays for different lateral shifts of the patches demonstrates possibility of controlling the aforementioned parameters

Efficient numerical investigation of an active reconfigurable periodicstructure

Application of an advanced numerical scheme, namely the Synthetic Function eXpansion (SFX) algorithm, to the analysis of an active 1D structure is presented. A passive periodic configuration consisting of parallel patches loading a microstrip line is turned into an active structure by inserting a pair of 2 switches to the two ends of each patch; the states of the pair of switches are changed contemporaneously. Variation of the states of the switches modifies the current distribution on the structure. The characterization of the large number of possible configurations requires a huge numerical effort which is alleviate by the use of the proposed method. Examples of the numerical investigations in a case of a 120 element array controlled by different periodic patterns are considered and discusse