Extension of Fresnel Near-Field Region by Single-Cycle Sinusoidal Pulses
NAVAL RESEARCH LAB WASHINGTON DC
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A circular conducting disk antenna is excited by three uniform current waveforms namely, a very high frequency CW sin , a single-cycle sinwO1, and a single-cycle coswOt. The energy per cycle associated with each of these waveform is taken to be the uM. From the behavior of the radiated energy densities along the axis of the disk, it is found that if the CW waveform extends the near field to unit distance, then the corresponding distances are 1. 375 and 3.75 for the single-cycle sinwOt and the single-cycle coswOt respectively. These results show that the method of energy transfer to a large distance along the axis of an aperture or disk becomes more efficient when a short pulse, instead of a CW source, is applied. This will have applications wherever a transmission of high intensity beam of energy far away from a radiating device is needed.
- Electrical and Electronic Equipment
- Radiofrequency Wave Propagation