Analysis and evaluation of Project Evergreen data

Abstract

Project Evergreen was an experiment conducted to evaluate antenna responses to nanosecond pulses and the capability of broadband equipment to capture them. The two antennas tested were a log periodic antenna modified by Lawrence Livermore National Laboratories and a TEM horn antenna. Analysis of the data collected by the Naval Postgraduate School test site personnel indicated the following: (1) The antenna output response characteristic is different for the log periodic antenna and the TEM horn antenna. (2) The received polarization is a function of the transmitted polarization and the orientation of the receiving site relative to the transmitting site. (3) Signal strength and capture are a function of the polarization alignment of the transmitting and receiving antenna. (4) Pulses on the order of 1 to 10 nanoseconds require bandwidth exceeding 1 Gigahertz (GHz) in the transmitting and receiving equipment. (5) Broadband equipment with minimum bandwidths of 1 GHz are required to adequately capture and process extremely short time duration signals