Experimental Determination of the Static Properties of a Towable VHF-UHF Horizontal Electrode Antenna.

摘要

The static properties of impedance, radiation resistance, spatial pattern, power gain, and frequency response have been investigated for an experimental horizontal electrode antenna in the frequency range of 150 to 400 MHz. This antenna was designed to receive low data rate satellite communications with optimum performance near 250 MHz when towed near the surface of the ocean. The observed power gain and frequency response are compared to those of an experimental slot antenna borrowed from the Massachusetts Institute of Technology, Lincoln Laboratories. It was found that the electrode antenna had at resonance (250 MHz) an impedance of 170 ohms, a radiation resistance of 0.37 ohms, a power gain of -18 dBi into a 50 ohm load (-16.5 dBi into a 170 ohm load), and a 3 dB passband of about 140 MHz compared to the slot antenna's properties of -9.7 dBi static gain and 11.5 MHz passband. At incidence angles close to vertical the frequency response of the electrode antenna is described well by the expressions developed in the text. Reference material is cited to support the contention that the dynamical performance of the electrode antenna (while in tow) cannot be accurately predicted on the basis of static measurements alone. Nevertheless, because of the 7 dB advantage in static gain that the slot antenna exhibits over the electrode antenna, it is unlikely that the electrode antenna will offer an advantage except when bandwidths much greater than 10 MHz are required. (Author)