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A simple radio frequency (RF) testing system that can be conveniently built and used for measuring radio propagation in tunnels is introduced. With the proposed testing system, RF power attenuation with distance in a train tunnel was measured at four frequencies (455, 915, 2450, and 5800 MHz) for both horizontal and vertical polarizations. Two analytical modeling methods—the ray tracing and modal...
This paper presents RF power density measurements carried out at an automobile manufacturing plant in the UK. This measurement campaign was carried out in order to quantify the amount of ambient RF power available within the plant. Due to the location of the plant, low power density measurements were recorded in the base-station downlink. The dominant frequencies at the plant were GSM-1800 and 3G...
In this paper, the results of outdoor RF spectral survey carried out in an urban area in Southern China are presented. The motivation of this work has been an attempt to record the dataset of ambient RF power radiated by the mobile base stations and Wi-Fi hotspots in the urban environment so as to select the frequency bands most suitable for the future ambient energy harvesting prototype design. RF...
As mandated by the 2006 Mine Improvement and New Emergency Response (MINER) Act, many underground coal mines have installed UHF radio systems to provide communications between personnel on the surface and underground. In an effort to better understand UHF signal propagation in tunnel environments, we made radio signal attenuation measurements in concrete tunnels at frequencies of 455 MHz, 915 MHz,...
An efficient and successful multi-channel rectifier for ambient RF energy harvesting has been designed and evaluated at GSM-1800 and UTMS-2100 bands. This design could sufficiently enhance the RF-to-DC power conversion efficiency (PCE) in weak signal reception environment. The validity of the proposed design is verified by detailed experimental results, which indicate that a maximum PEC of 38.8% and...
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