Resistor-Loaded Wideband Polarization Independent Absorber Using Tightly Coupled Dipole Structure

This article presents a resistor-loaded wideband absorber using a tightly coupled dipole structure. The conversional inherit wide bandwidth tightly coupled dipole which was used as an antenna is adopted as a unit cell. The port of the dipole is loaded with resistors to dissipate the microwave energy. The design principles of the absorber are given. An equivalent circuit model composed of an RLC resonant circuit is proposed to analyze the performance of the absorber. To demonstrate, a 288 mm × 288 mm absorber ranging from 1.96 to 8.08 GHz is fabricated and measured. The measured results agree well with the simulated ones which show that the absorber can work from 2 to 8.18 GHz with an absorption rate of more than 90%. Moreover, the proposed absorber is also insensitive to the polarization angle of the incident wave. When the incident angle changes from 0° to 45°, the absorption rate is nearly unchanged over the operating band.