Investigation on convenient measuring method of oblique incident characteristics for absorbing panel in low frequency range (lower than 1 GHz)

The ferrite absorbing panel used for suppressing TV ghost images caused by TV wave reflection from tall buildings and the RF absorber used for an anechoic chamber have been realized for many years. The convenient and accurate measuring method of the reflectivity characteristics of RF absorbers against the oblique incidence in the low frequency range (lower than 1 GHz) is investigated by using a new time domain reflectometer method. The direct wave vector from the transmitting antenna to the receiving antenna and the undesired reflection vector can be eliminated by means of a mathematical treatment or by subtraction of the receiving signal without the target from that signal with the target in advance of time gating in the desired response. By using these new methods, a convenient and efficient evaluation method for an RF absorbing panel and absorber could be realized.