First results of the JUNO/Waves antenna investigations

Waves is the radio and plasma wave instrument onboard NASA´s spacecraft JUNO. The instrument utilizes an electrically short dipole antenna for the measurement of electromagnetic field parameters. The instrument is devised for frequencies from 50 Hz up to 40 MHz. Waves antenna system properties are distorted because the highly conducting spacecraft body is in close vicinity of the antennas. In addition the antenna system is not tri-axial and goniopolarimetry techniques like polarization analysis and direction finding depend crucially on the true antenna properties. In the case of the Waves instrument, mentioned techniques have to rely on a rotating dipole method for detection of parameters like the wave incident direction. In this contribution we outline the first step to acquire the true antenna properties of the Waves antennas. We present the first results of our numerical investigations, the antenna monopole effective length vectors and antenna transfer matrices for the quasi static regime.