Hybrid Jauman absorber for the mm-wavebands


  • Ousbäck Jan-Olof
  • Larsson Fritz

Publish date: 2003-01-01

Report number: FOI-R--0812--SE

Pages: 36

Written in: Swedish


The report presents a work to realise a formerly presented radar absorber namely a load carrying hybrid Jauman absorber optimised for the Ka- and W-bands. The absorber consists of a thin resistive sheet enclosed by two dielectric layers. As resistive sheet a conductive polymer treated fabric has been used and as dielectric layers glass fibre reinforced plastics. Perturbation analysis has been performed under the assumption that the resistive sheet has negligible thickness in order to get tolerances of design parameters. Two absorbing panels manufactured under strict control worked in the Ka- but did not work in the W-band, probably depending on the fact that the resistive sheet in this case cannot be considered as having negligible thickness. Deeper perturbation analysis including both thickness and dielectric constant of the resistive sheet has been performed in order to get knowledge about the influence of them. The hybrid Jauman absorber that was manufactured after that the analysis was done had a resistive sheet with a thickness half that of the two previous panels. Even this absorber worked only in the Ka-band. It seems that the dielectric characterisation of the resistive sheet is not correct. However during the time FOI has worked with this matter a successful result has been reported on a panel with the same resistive sheet we first used. This result may be questionable from the thorough analysis performed at FOI. The conductivity of the resistive sheet decreases with time due to ageing. The effect of ageing is described as a function of selected environmental parameters.