Design and analysis of a frequency selective radome (FSR) with wideband absorbing properties

A novel frequency selective radome (FSR), which is “transparent” within the operating band of the antenna while absorbing out-of-band incoming waves in a very wide band, is presented in this article. In order to absorb undesired signals out of the band, square loops loaded with lumped resistors are used. The pass-band property is realized by employing meandering square slots with a smaller period to enhance the stability under large incident angles. The equivalent circuit method is introduced to explain the working principles of the FSR and verify the full-wave simulation results based on the FEM codes. The structure's performances under oblique incidences are also investigated.