Magnetoelectric (ME) antenna has proven to be an effective solution for antenna miniaturization. In recent years, the ME antennas adopted for communication in atmospheric and water environment has been verified. The ocean accounts for about 71% of the Earth’s surface area, which can be used for environmental monitoring, weather forecasting, earthquake forewarning, and marine biological research. The exploration and development of ocean resources depend on underwater communication, so it is promising to study the communication of low-frequency (LF) ME antennas in seawater environments with lossy media. In this work, a laminated sandwich-structured Terfenol-D/lead zirconate titanate (PZT)/Terfenol-D based on an acoustically actuated compact LF ME antenna with 91.8 kHz frequency is proposed to realize bidirectional communication in saline environment with the conductivity of 5 S/m. Experimental results show that the proposed ME antenna achieves the best performance under the action of a 300 Oe dc-biased magnetic field, and the near-field radiation characteristics in the yo z plane and the xo z plane are equivalent to those of the magnetic dipole antenna. In a saltwater environment, the proposed ME antenna is capable of transmitting and receiving electromagnetic (EM) waves, and an effective communication distance of 30 cm is realized by amplitude shift keying (ASK) modulation. This research shed light on the miniaturized LF ME antenna that can realize bidirectional wireless communication in lossy media (such as seawater environment), which is expected to provide technological support of communication for ocean exploration.

In recent decades, gallium nitride (GaN) high-electron-mobility transistor (HEMT) has become increasingly popular for microwave applications due to its wide bandgap and high saturated electron velocity. However, self-heating inhibits the improvement of its electrical characteristics and reduces device reliability. In this study, a thermoelectric analysis based on embedded microfluidic cooling is performed. By embedding the microchannel into the silicon carbide (SiC) substrate, the coolant can be introduced directly to realize active near junction cooling. According to the thermal resistance model, embedded cooling shortens the thermal path and enhances the capacity of heat convection, and the improvement in the HEMT output characteristics is also verified experimentally. The saturation current increases by 19.5%, and the heat flux of the gates reaches 6349.2 W/mm2 at 70 mL/min, which is 1172% higher than that of traditional remote cooling. The maximum temperature is only 67.4 °C. Therefore, the embedded microfluidic cooling scheme can markedly suppress the self-heating effect and further explore the electrical potential of GaN-based devices.

When flight vehicles (e.g., aerospace vehicles, Low Earth Orbit (LEO) satellites, near-space aircrafts, Unmanned Aerial Vehicles (UAVs) and drones) fly at high speed, their surfaces suffer the micro-pressure from high-altitude thin air. The long-term effect of this pressure causes the surface components of flight vehicle to deform or fall off, which can lead to a serious accident. To solve this problem, this paper proposes a sensitivity-compensated micro-pressure flexible sensor based on hyper-elastic plastic material and plate parallel capacitance. The sensor is able to measure a range of 0–6 kPa micro-pressure suffered by the flight vehicle’s surface with high sensitivity and flexible devices. In this paper, we propose the principle, structure design and fabrication of the sensitivity-compensated micro-pressure flexible sensor. We carried out experiments to obtain the static characteristic curve between micro-pressure and the output capacitance of the sensor devices, and investigated the relationship between sensitivity and geometric parameters. We also compared the performance of the flexible sensor before and after sensitivity compensation. The result shows that the sensor can measure a range of 0–2 kPa and 2–6 kPa with a sensitivity of 0.27 kPa⁻¹ and 0.021 kPa⁻¹, which are 80% and 141.38% higher than the sensor before compensation; a linearity of 1.39% and 2.88%, which are 51.7% and 13.1% higher than the sensor before compensation; and a hysteresis and repeatability of 4.95% and 2.38%, respectively. The sensor has potential applications in flight vehicles to measure the micro-pressure with high sensitivity and flexibility.

This paper summarizes the current issues and challenges of aerospace control techniques, and generalizes the basic problems and key technologies of launch vehicles and aerospace flights in the next generation. And it analyzes the research progresses of aerospace control at present stage. Moreover, it proposes some suggestions of development of aerospace control in the future.

In this paper, high performance InGaN double channel (DC) high electron mobility transistors (HEMTs) are proposed and systematically investigated. Due to the coordination of double InGaN channels, a large maximum drain current density and a distinct double-hump feature of the transconductance and frequency performance are achieved. More importantly, it is revealed that the coupling effect between the two InGaN channels is much stronger than that of the conventional GaN DC HEMTs. This characteristic leads to a remarkable enhancement in the gate voltage swing, indicating the excellent linearity of the InGaN DC HEMTs at both dc and rf conditions. Benefiting from the enhanced electron confinement in InGaN channels, the fabricated HEMTs show a low off state drain leakage current of 0.26 μA/mm and a high on/off current ratio (I_on/I_off) of 5.1 × 10⁶. In addition, the desirable current collapse and breakdown characteristics are also obtained. This work convincingly demonstrates the great potential and practicality of the InGaN DC HEMTs for high power and high bandwidth applications.

This paper develops a fuzzy disturbance observer-based fixed-time control technique to solve the attitude-tracking problems for hypersonic morphing vehicles (HMVs). According to the dynamic model of HMVs, the control-oriented model is established to simplify the design procedure. Fuzzy fixed-time disturbance observers are proposed for high-precision and fast disturbance estimation. The attitude controller is developed based on multivariable sliding mode control and fixed-time stability technique. Compared to the conventional fixed-time control methods, this paper adopts variable exponent coefficients to achieve fixed-time stability. The controller will be obtained without lengthy inner and outer loop design procedures. The closed-loop stability is proved via Lyapunov synthesis. Finally, several scenarios are designed to assess performance.