The analysis, design, and realization of a modified bow-tie antenna optimized for impulse ground penetrating radar (GPR) applications is described. The proposed antenna shows improved properties important for GPR, which include its compact size (in comparison with a conventional bow-tie antenna) and ability to radiate UWB pulses with increased amplitude and very small late-time ringing. A substantial increase in the amplitude of the transmitted pulse is achieved by utilizing radiation from discontinuities introduced by the resistive loading employed in the antenna to suppress late-time ringing. By choosing an optimal distance between the antenna's feed point and the location of the resistive loading, radiations that occur from the antenna's feed point and the mentioned discontinuities at the resistive loading will combine constructively in the boreside direction of the antenna. As a result, one will observe a substantial increase of the amplitude of the transmitted pulse in the boreside direction. Furthermore, an analytical expression describing approximate time-harmonic current distribution is derived to indicate an optimal resistive loading profile for the proposed antenna. Additionally, the traveling-wave current distribution of the antenna is theoretically analyzed to examine the applicability of the obtained time-harmonic expression for pulse excitation. It has been found that when the antenna is resistively loaded both the time-harmonic and traveling-wave currents decay to approach nearly the same value at the end section of the antenna. As the amount of current at the antenna ends corresponds to the level of reflection which occurs there, the derived expression is found to be useful to indicate an optimal loading profile for the proposed antenna. A theoretical model of the proposed antenna has been developed to perform numerical analysis using a modified NEC-2 code. In addition, an experimental verification has been carried out and both the simulation and experiment confirmed the improved properties of the proposed antenna.
Abstract:The tracking Mean Square Error (MSE) of the least squares (LS) Multiple Input Multiple Output (MIMO) channel estimation in rician flat fading channel is derived in closed-form, which is then verified by Monte Carlo simulation. The channel accomodates applications where the elevation angle between the transmitter and the receiver dictates the doppler shift of the Line of Sight (LOS) component, as encountered in communications from satellite or High Altitude Platform (HAP) to a moving mobile. A higher tracking loss is revealed as the mobile travels to a lower elevation angle.
This study analyzes the strategy of determining economic development planning on SME improvement in Indonesia. A qualitative approach was conducted through interview questionnaires with twenty respondents, including sixteen Regional Apparatus Work Unit, Fisheries and Marine Office lecturers, subdistrict heads, and development observers. The method used is Analytical Hierarchy Process (AHP). AHP prioritizes criteria and sub-criteria to increase economic growth, reduce poverty, and increase community participation, while indicating the sub-criteria to optimize resource potential, strengthen micro-economy, develop tourism potential, utilize fishery potential and cultivation, and improve institutional performance. The AHP weighting results based on competitiveness and regional development of Bantaeng Regency is the priority in policy-making for a solution. The research shows that the government strategy, based on the perception of the stakeholders, is: optimizing resources strategy with priority to maximize the resource-carrying capacity that includes agriculture and farm, tourism development potential strategy, self-reliance of community groups and coaching and management. Strategies to strengthen micro economy include: industrial control, SMEs, community cooperatives and infrastructure improvements, strategies to improve institutional performance work capacity and work ethic, and strategies to utilize fisheries and cultivation potential technological development, provision of processed industries of fishery products, and improvement of the quality of the environment.
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