Full scale low-cost ultra wide band antenna for SKA low frequency array

[摘要] ENGLISH ABSTRACT: This thesis is about the design, simulation and measuring of ultra wide band antennasfor use in the Square Kilometre Array (SKA).The SKA is a radio astronomy project with one of the aims of detecting hydrogen particlesin deep space. Several thousand antennas over a wide band of frequencies are neededto receive the radiation from these particles. This motivates the need for a low-cost ultrawide band antenna with the focus on the low frequency part of the SKA.In this thesis we present two design strategies:The first design strategy is for a printed LPDA on a substrate and design curves aregenerated. A scale model was built and measurements did not correlate with simulationresults. This is due to manufacturing tolerances and assembly of the pyramidal structure.The second design strategy is for a full scale zig-zag antenna and design curves were alsogenerated. The aim here is to produce a low-cost prototype by using brazing rods forthe wire structure and mount it on a wooden frame. A full scale model was built andmeasurements on the roof produced much interference for the radiation pattern, but thereflection coefficient was good. We suggest doing measurements in an interference freeenvironment in order to achieve the needed results.To conclude we suggest using the zig-zag antenna for the SKA. Some issues do howeverneed more attention as the transformer has some losses, the cross polarisation is probablynot good enough and the beamwidth does not reach the specification. We demonstrateda low cost prototype and there is the possibility of low-cost large scale manufacturing but this needs to be addressed. This has however not been analysed as many factors for largescale manufacturing are very difficult to predict beforehand and lies outside the scope ofthis thesis.

[发布机构] Stellenbosch University