Abstract-In this paper, a miniaturized dipole antenna operating at 100 MHz frequency for Ground Penetrating Radar (GPR) application is presented. A conventional dipole antenna length is half of its lowest operating frequency wavelength. As low frequency GPR system is vital for high depth penetration, the size of the antenna used reduces its easy handling and portability. Therefore, the technique of miniaturizing a dipole antenna by adding extra radiating arms is presented here. The antenna design and analysis is carried out using Advanced Design System (ADS) and FEKO simulation software, and a network analyser is used to validate the prototype antenna performance. The antenna of 66.5 × 22 cm dimension, fabricated on an FR4 substrate exhibits a frequency resonance at 104 MHz with 8 MHz of −10 dB bandwidth. The proposed antenna radiates in omnidirectional pattern and features 55% reduction in length compared to a conventional dipole antenna of same frequency operation.

Decommissioning of nuclear structures requires cost effective remotely operated automated cutting techniques. Cutting with solid-state lasers employing optical fibre delivery of laser power in the multi-kilowatt range and with high focus ability of the beam offers the capability of a single laser source to address more than one type of process application. The high value asset, which is the laser itself, can be situated and maintained in a safe clean area, remote from the cutting, thus allowing the system to be reused for several other decommissioning applications. The problem then is to deploy the cutting head on the remote structure. This paper describes a 5kW laser cutting system deployed by a permanent magnet adhesion wall climbing robot developed to carry the payload comprising of the laser cutting head weighing 19 kg, optical fibre cables supplying power and control signals. Steel plates up to 40 mm thickness can be cut at speeds of 50 mm/min while 10 mm thick plates can be cut at greater speeds of 800 mm/min.

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