DUAL PULSES ANTENNA FOR GROUND PENETRATING RADAR (GPR) WITH LINEAR RESISTIVE LOADING

• Main Author: WAHYU (NIM : 33204304) Tim Pembimbing : Dr. Ir. Adit Kurniawan; Dr. Ir. Sugihartono; Prof. Ada, YUYU
• Format: Dissertations
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/17706
• Institution: Institut Teknologi Bandung

In a GPR survey to find objects of unknown depth require more than one type of pulse duration means using a number of antennas with different length. Modification of the profile method of Wu-King resistive loading with linear <br /> <br /> resistive loading been developed. Modifications of this method to produce two pulse antenna on a dipole shaped impulse GPR system and flare angle, linear resistive loading profile, and sorter optimum dimensions so that the resulting main pulse is transmitted over the Wu-King profile and ringing level lower than or equal to the Wu- King. GPR antenna prototypes for two of the most optimum <br /> <br /> pulse is proposed dipole antenna consists of two pairs of antennas, each of the main antenna (short-length) of the feed point to bending (discontinuity) is equal to 3 cm and 6.5 cm for the main antenna (long-length ). Each has a loading arm with a length of 26 cm to 22.5 cm for short and long. Flare angle between the main antenna of 70 degrees. The gradient of resistive loading is 31.25 ohms per <br /> <br /> centimeter. Model analysis for the coupling between the arms of the antenna mutual impedance analysis using two dipole orientation angle. Flare angle of 70 degree angles show mutual impedance lowest. This is consistent with FDTD <br /> <br /> simulation results that the lowest coupling occurs at an angle of 70 degree flares. Model analysis for linear-shaped resistive loading on arm of the antenna and length of antenna using the analysis of resistive cylindrical dipole antenna on time-harmonic. In this analysis model on the antenna circuit with gradient changes, changes in the resistive loading and changes in antenna length. This <br /> <br /> analysis model has limitations in the value of the gradient, above the 156.25 ohm cm loading is still effective to work but to a smaller gradient of 156.25 ohm / m no longer effective as an assignment so that the more dominant is his timeharmonic. For that as a solution using the analysis time-domain or FDTD. FDTD simulation results for two-pulse GPR antenna, among others, decreasing linear <br /> <br /> gradient, could increase the level of the main pulse and an increase in the level of late-time ringing. Decrease in long-arm antenna, could increase the level of the main pulse and an increase in late-time ringing. Results of measurement and the implementation of two-pulse antenna for GPR work in accordance with its function.