Abstract:
The Energy Selective Surfaces (ESSs) are periodic structures that loaded with nonlinear devices or materials to obtain high power protection functions. The proposed structure is realized by periodic split resonance rings (SRR) loaded with diodes or lumped capacitors. Specifically, there are two different SRRs in each unit and they are loaded with a diode and lumped capacitor, respectively. With a good design of the geometry parameters and lumped elements, a passband at S band (2. 6 - 2. 8 GHz) is generated by the SRR loaded with a lumped capacitor and a passband at C band (5. 5- 6 GHz) is generated by the SRR loaded with a diode. By the coupling effects between two SRRs, the two passbands are modulated simultaneously by only one diode. The physical mechanism is demonstrated with the distribution of surface currents density and electric field and some important parameters are also discussed in detail. It proves that the transmission characteristics of the passbands are determined by different parameters, respectively, and they can be modulated independently. Then a prototype of the proposed structure is fabricated and measured under low-power signals and high-power signals, respectively. The results of simulations and experiments agree well, showing that the proposed dual-band ESS poses an insertion loss lower than 1 dB during the two operating frequency band for low-power signals. And for high-power signals, the dual-band ESS provides more than 15 dB and 25 dB shielding in the operating frequency band in S and C band, respectively. The excellent nonlinear transmission characteristic and dual operating band make the proposed ESS practical for high power microwave protection.