A novel ultrawideband energy selective surface (ESS) in S-band is presented for adaptive high-power microwave (HPM) protection. Periodic metallic textures are designed and loaded with PIN diodes to obtain the nonlinear response that is dependent on the power intensity of incident wave. After the equivalent circuit analysis and full wave simulation, a prototype is fabricated and experiments are conducted under different power levels, which has a good coincident. The insertion loss is less than 1 dB for low-power signals in operating band, while the shielding effectiveness is more than 20 dB when exposed to HPM. Both the measurement results of frequency and time domain have verified the nonlinear transmission characteristics, which demonstrated the HPM protection abilities of the proposed ESS.

This paper presents a detailed circuit analysis of Energy Selective Surface (ESS), which adaptively protects electronic equipments from high-power microwave (HPM) thanks to its self-actuated response and nonlinear transmission feature. With the help of equivalent circuit model (ECM), four types of ESS schemes are individuated and two of them are analyzed in detail to explore the influence of ECM parameters on the performance of ESS. Then, a high performance ESS is designed through the proposed method. The proposed structure is realized by metal periodic structures loaded with diodes and lumped capacitors. A prototype is fabricated and measured. The results of simulations and experiments agree well, showing that the proposed ESS provides more than 30 dB shielding for high power signals and an insertion loss lower than 1 dB for low-power signals. The excellent nonlinear transmission characteristic makes the proposed ESS practical for HPM protection.

The current research on the global navigation satellite system (GNSS) has shifted to focus on providing secure and reliable services, rather than high-precision positioning services. Deception jamming has emerged as a major threat to GNSS security applications due to its advantages such as concealment. For security signals not publicly available in the spread spectrum code sequence, simple deception methods do not suffice to implement effective deception. In response, the security code estimation and replay (SCER) attack was proposed. However, the impact of the spread spectrum code estimation error on the receiver and SCER attack effect is still unclear. This paper is based on the SCER attack and deception signal receiving model, constructs a receiver tracking loop analysis model and carrier to noise ratio (CNR) estimation model based on spread spectrum code error, and analyzes the impact of spread spectrum code error on the receiver tracking loop and CNR. Based on the experimental results and discussion, some conclusions have been drawn. Firstly, spread spectrum code error will cause correlation peak distortion and a decrease in CNR. Secondly, to achieve effective deception, the spread spectrum code error cannot be increased indefinitely and an upper bound exists, which ranges from about 41%, depending on the deceived receiver acquisition strategy. Thirdly, when the spread spectrum code error rate is less than the upper bound, the mean square error of the code phase measurement is less than 0.02 chip, which is on the same order of magnitude as caused by thermal noise. As such, it can be approximately assumed that the code tracking deviation caused by spread spectrum code error has minimal impact on the SCER attack. Although reducing the receiving terminal gain of the SCER attack will lead to an increase in the spread spectrum code estimation error, it is possible to increase the transmitting terminal gain of the SCER attack to maintain the same CNR of the deception signal and deception effect, greatly reducing the cost of the deception.

This paper presents a gain reconfigurable reflector antenna that could adaptively focus or defocus to adjust gain, thereby preventing the high-intensity radiation fields (HIRF). The reflector’s surface is partially covered by the field-induced artificial magnetic conductor (F-AMC). According to the status of diodes loaded in F-AMC, the reflection characteristics could be switched between electric and magnetic conductors. When field intensity is low, the diodes are OFF-state, and the reflection phase is about 180°, performing as an electric conductor; once the diodes are triggered into ON-state by the high-intensity field, the reflection phase would switch to nearly 0° and perform as a magnetic conductor. Through non-periodically arranging and optimizing the number of F-AMC unit cells on the reflector surface, the phase distribution of the wavefront would remain uniform in a low-intensity environment and be messed under HIRF. The messed phase of the wavefront could defocus the radiation beam and reduce the gain to prevent the high-intensity fields from being received. After simulation and measurement, the proposed reflector antenna was demonstrated to decrease its gain by more than 20 dB under HIRF. The gain difference from loading the F-AMC was less than 1 dB in the band from 8.4 GHz to 9.8 GHz in the low-intensity environment.

In this article, a wideband energy selective surface (ESS) with quasi-elliptic response and high shielding effectiveness is proposed for providing out-of-band rejection and high-power microwave protection at the same time for wideband systems. By cascading three layers of structures and loading diodes, wideband quasi-elliptic response and nonlinear transmission property are realized. The ESS has a wide pass-band and high out-of-band rejection simultaneously with turned off diodes under a low-power incidence. On the contrary, under a high-power incident wave, diodes are turned on adaptively, leading to a high shielding in wideband. An equivalent circuit model is first designed in which a three-order Chebyshev filter with a serial LC and diodes is schemed. ESS structure is then constructed based on the circuit model. Field-circuit cosimulation is employed to analyze the power-dependent transmission property. In addition, two prototypes are designed and measured in rectangular waveguides, where it can be seen that the simulation and measurement findings agree well. The proposed ESS has a wide pass-band of 6–10 GHz and great out-of-band rejection with one transmission zero at 11.6 GHz under a low-power incidence, whereas high shielding in wideband is observed for high-power incidence.

An ultrawideband energy selective surface (ESS) for adaptive prevention of high-intensity radiation fields (HIRF) is proposed in this paper. With a triple-layer structure loaded with PIN diodes, the ultrawideband transmission property from C- to X-band was achieved in both the OFF- and ON-state of the diode. Without active biasing, the state of the loaded diodes was directly controlled by the intensity of the incident waves. Unlike the low insertion loss (IL) realized in OFF-state, the shielding effectiveness (SE) in ON-state was high to prevent the incident waves. Therefore, the proposed ESS could adaptively respond to the HIRF’s illumination and simultaneously switch its transmission property. After full-wave simulations and waveguide measurements, the bandwidth of IL below 1 dB and SE over 20 dB were achieved from 6.30 GHz to 12.20 GHz, demonstrating a 64% fractional bandwidth for HIRF prevention.