Novel Synthesis Design of Ultrawideband Microwave Absorbers Under Specific Oblique Incidence Operation

In this Letter, a novel synthesis method for the dual-polarized ultrawideband microwave absorber (MA) under specific oblique incidence operation is proposed, utilizing a polarization separation design. Each MA element is composed of slotline resonators and thin-film resistors. Accurate equivalent circuit models (ECMs) are then established to explain the absorption mechanism. The transfer function of the ECM is mapped to the desired real rational function to determine circuit parameters for specific design specifications. To verify the theoretical predictions, prototypes with the same and different specifications for dual polarizations are designed under various large incidence angles. Additionally, a more generalized prototype with different specifications is fabricated and measured. All simulated and experimental results validate the efficacy of the synthesis design method, which presents an accurate and efficient solution for designing dual-polarized ultrawideband MAs under specific oblique incidence operation.