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In this work, we demonstrate a flexible frequency-selective rasorber (FSR) with great angular stability and conformal superiority using metal-graphene hybrid metamaterial. The metamaterial is fabricated by filling the designed metal patterns with graphene-based ink. It can replace the traditional resistors to introduce loss for the absorption purpose. Therefore, the FSR does not need any lumped components soldered onto its surface, enabling a high flexibility and conformal capability. The metal-graphene FSR is fabricated and measured on flexible substrates that have a 60° angular stability and a 128° conformal angle. The simulations and experiments confirmed that the proposed metal-graphene FSR exhibits excellent angular stability and considerable flexibility, making it ideal for stealth systems.

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A dual-band independently beam steering THz antenna is presented, which is composed of a broadband omnidirectional monopole source antenna surrounded by six hexagonal active frequency selective surface (AFSS) screens with switchable filtering response in two bands. By controlling the chemical potential from 0 eV to 0.5 eV, the AFSS screen can achieve the conversion between high transmission (ON state) and almost total reflection (OFF state) at two frequency ranges independently. Therefore, the radiation beams of the THz antenna in two bands can be steered from 360° large angle scanning and omnidirectional radiation with flexible combinations.

In this paper, the shock train in the isolator is taken as the research object, and the method of detecting the leading edge position of the shock train during self-excited oscillation and forced oscillation is studied by conducting the wind tunnel test. A steady-state throttling system and a fluctuating throttling system are designed to apply the required steady-state and fluctuating back pressure downstream of the isolator. Then, the four methods of pressure ratio method, pressure difference method, standard deviation method, and Fast Fourier Transform (FFT) analysis method are used to detect and study the position of the shock train leading edge under steady and fluctuating back pressure to verify their applicability. The results show that under the condition of steady-state back pressure, the four methods can get effective results, and the results are consistent. Under the condition of fluctuating back pressure, the pressure difference method could not give effective results, but the other three methods could give effective and consistent results. And the results of the standard deviation method and the Fast Fourier Transform analysis method are similar in image and principle.