The escalating power density in Active Phased Array Radar has made the thermal management of Transmitter and Receiver (T/R) modules a critical bottleneck for radar performance. To address the thermal resistance of traditional cold plates, this study investigates an innovative embedded cooling strategy utilizing micro-pyramid arrays and advanced nanofluids. Thermal performance was evaluated using maximum temperature, maximum temperature difference and surface temperature standard deviation (ST). Higher pyramid density markedly enhances temperature uniformity, an effect that scales positively with the power load. Under a 100 W condition, the 8-circle micro-pyramids configuration (the densest structure with roughness Ra = 1.3) achieved a 22.58 K reduction in maximum temperature and a 22.5% improvement in temperature uniformity compared to the 2-circle structure, and outperformed the 4-circle structure by 16.98 K and 17.9%, respectively. Furthermore, a comparative analysis of nanofluids (Al2O3, CuO, graphene, and h-BN) is conducted and it is found that graphene nanofluid exhibits the best overall heat transfer enhancement because of its high thermal conductivity and moderate reduction in specific heat capacity. The thermal performance of the nanofluid is evaluated by comparing the maximum temperatures of the heat source at the 8-circle structure. The synergistic coupling of graphene nanofluid with the 8-circle array yields a remarkable 35.38% enhancement in temperature uniformity at 100 W. The enhancement mechanisms are mainly attributed to intrinsic thermophysical properties of the nanoparticles and convection caused by denser pyramid array. The aforementioned findings provide important guidance for the thermal management design of antenna and other high-density integrated electronic systems with embedded cold plate design demand.

Electrolytic double-layer gate insulation transistors (EDLGITs) have gained significant attention recently due to their features for achieving high-density charge accumulation and low operating voltage. This is primarily attributed to the large capacitance of the electrolyte insulation in these devices. This article proposes a physical model for the capacitance of the electrolytic double-layer gate insulation (EDLGI) and the drain current of amorphous InGaZnO (a-IGZO) EDLGITs based on the channel surface potential. It is demonstrated that the EDLGI capacitance, which comprises the compact-layer and diffuse-layer capacitances, is not only influenced by the characteristics of the electrolyte but also by the gate voltage. Furthermore, the frequency-dependent equivalent capacitance of the electrolyte insulation (C-seq) under ac gate voltage in a-IGZO EDLGITs is analyzed. The drain current and C-seq calculated using our model show good consistency with the reported experimental data.

Early warning unmanned aerial vehicles (UAVs) possess the capability for long-range flight and operations at medium-to-low altitudes, enabling large-scale deployment within distant naval fleets for extended patrol missions. Operating in harsh environments characterized by aerodynamic forces, vibrations, impacts, and high temperatures, the conformal load-bearing antenna structures on these UAVs may undergo minor or permanent deformations, causing positional deviations of antenna elements and resulting in degraded electrical performance. Therefore, precise sensing of antenna structural deformations is essential for real-time compensation of performance losses. This study introduces the Radial Basis Function (RBF) interpolation method, utilizing a limited number of strain sensors to accurately reconstruct strain values at unsensed locations. A high-precision inverse finite element deformation sensing method based on RBF-iQS4 theory is proposed for conformal load-bearing antennas on UAV wings. The method is validated using a Global Hawk UAV model, demonstrating its effectiveness in deformation sensing and structural monitoring.

The missile - borne phased array antenna plays a crucial role in modern military applications. The radome, an important component for protecting the antenna from harsh environments, can cause changes in the physical properties of the antenna's interior and exterior due to high - temperature ablation during missile flight. These changes significantly affect the antenna's radiation performance. Thus, it is necessary to adjust the amplitude and phase of the excitation current of the array elements. To solve this problem, this study proposes a hybrid model based on MTL-CNN-LSTM to predict the adjustment values of the amplitude and phase of the antenna excitation current. Firstly, by collecting the missile's flight parameters and the antenna's physical parameters, and after pre-processing, a multi - task spatio-temporal fusion prediction model is constructed to predict the adjustment values of the amplitude and phase simultaneously. Then, the far - field pattern of the antenna obtained through simulation is used for verification. The results show that the hybrid model is significantly superior to traditional methods in terms of prediction accuracy and stability.

In this paper, we first analyse the challenges and requirements in the assembly process of missile-borne phased array antenna seeker. These challenges include assembly complexity, assembly accuracy requirements, assembly sequence and so on. Secondly, we introduce the overall layout and key technologies of the design system, including assembly structure tree, assembly sequence planning, assembly constraint analysis and so on. According to these requirements, we specifically designed an automatic assembly system for missile-borne phased array antenna seeker based on Creo secondary development. Using the Pro/Toolkit secondary development toolkit contained in Creo, and using Microsoft Visual Studio as a compilation tool, the radome, array element, mounting plate, array element, T/R and bottom plate of the seeker are assembled and designed. The constraint relationship, assembly position and assembly sequence of the parts are determined, and the design of the automatic assembly system is completed. By using this system, we can easily complete the assembly process after optimization and modification in the subsequent rapid design configuration.

Embedded microchannels cooling technology significantly reduces thermal resistance by enabling direct contact between the coolant and the heat-generating chip, exhibiting an incomparable cooling effect compared to traditional methods. However, direct contact between the coolant and the heat source results in more significant temperature fluctuations on chip and increased pressure sensitivity in the microchannel. These factors have become key factors restricting further improvement of the system's energy efficiency. This paper proposes an embedded chip cooling system that is easy to implant with great thermal performance. An embedded microchannels with secondary channels of airfoil cavity pin-fin spoiler structure (EMAT-SC), designed to further enhance the heat transfer capabilities of embedded microchannels cooling while ensuring the stability of the embedded cooling system. Through numerical simulation methods, it is determined that EMAT-SC can obtain the best heat dissipation performance when the relative width of secondary channel (alpha) is about 0.47 and the relative size of spoiler structure (beta) is in the range of 0.28-0.56. Based on these findings, we further compared the cooling performance of the EMAT-SC with that of the embedded microchannels with rectangular structure (EMRR), the embedded microchannels with triangular rib groove structure (EMTR), and the embedded microchannels with conventional secondary channels structure (EMSC). The results confirm that EMAT-SC can not only maintain a Delta p comparable to that of EMTR, but also exhibits superior heat transfer performance. The performance evaluation criterion (PEC) of EMAT-SC reaches 1.50 at Re = 783, which shows the best comprehensive thermal performance compared with the optimization schemes of the same size in recent years. This study offers valuable insights and serves as a reference for embedded cooling system solutions aimed at high heat flux density electronic equipment, particularly in synergistic thermo-hydraulic optimization of embedded microchannels.

In this paper, the possibility to improve target detection performance in passive bistatic radar by jointly exploiting multiple signals at different carrier frequencies emitted by the same illuminator is investigated, namely multi-frequency passive bistatic radar (MFPBR) coherent integration. Since the carrier frequency of each signal is agile, the MFPBR coherent integration suffers from the problems of range phase incoherence and Doppler broadening. In order to tackle these challenges, a multi-frequency coherent integration target detection algorithm for passive bistatic radar is proposed. Specifically, this scheme corrects the Doppler broadening effect via TSP. Then, low sidelobe filtering based on convex optimization is carried out to remove the range phase incoherence and obtain the MF of the target's energy. Meanwhile, the high-range-resolution profiles (HRRP) of target can be generated. The advantage of the proposed algorithm is that it can obtain superior coherent integration and detection performance for both the single and multiple targets scenarios compared to existing methods. Finally, a series of measured and simulation results are presented to demonstrate the effectiveness of the proposed algorithm.

Reflector antenna has been widely used in deep space exploration, radar warning, and other fields, all of which requires high pointing accuracy. The antenna elevation bearings are the key component that guarantees its pointing accuracy, while any degradation or fault can seriously affect the antenna’s performance, leading to deviations in antenna pointing and instability during operation. However, the relationship between the antenna elevation bearing fault and its pointing accuracy remains unclear because there is insufficient experimental faulty transmission data and pointing error collected from the test-rig simultaneously. Therefore, this paper aims to establish a deep learning model-based relationship to reveal the underlying relationship between the antenna transmission faults and its pointing accuracy. By linking the two, transmission faults in key components can serve as a substitute for pointing accuracy as one of the criteria for antenna maintenance decisions, vibration signals, serving as a basis for fault diagnosis, can be collected and processed in real-time without the need for equipment shutdowns, undoubtedly bringing convenience to antenna maintenance providing a theoretical basis for the development of antenna maintenance strategies. In order to overcome the problem of insufficient data, this paper has established an antenna elevation system dynamic simulation model containing pre-defined transmission faults. Furthermore, to link antenna fault diagnosis with antenna pointing errors, a mathematical model for antenna axis error analysis has been established. Finally, labeled fault data and antenna pointing errors have been put into the deep neural network model for training to obtain the prediction model for predicting antenna axis error. The results showed that faults in the key transmission components have a significant impact on antenna pointing errors and the proposed deep neural network learning model exhibits a high predictive accuracy.

To address the complexity of full-array antenna simulation models and reduce computational demands, this study introduces an innovative design and simulation method for phased array antennas based on metasurfaces with composite periodic structures. This approach harnesses the arithmetic phase differences between array elements to engineer a phased array capable of beam scanning, thereby simplifying the complex initial model into a streamlined basic unit cell model with periodic boundary conditions, which significantly enhances the efficiency and speed of full-array antenna design and analysis. In this research, we constructed two types of phased arrays using microstrip patch antennas with composite periodic structures: a comprehensive full-array model and a periodic model. Finite element simulation results have confirmed a high level of consistency in antenna gain between these two models. The simulation and analysis method presented in this paper not only effectively reduces the complexity of the simulation model but also conserves computational resources without sacrificing the accuracy of the results, providing an effective computational strategy for the design and simulation analysis of complex full-array antennas.

With the continuous breakthroughs in modern construction technology, large-span spatial structures hold promise for urban construction. However, the great responsibility borne by such buildings makes their structural health crucial. Therefore, it is necessary to carry out the structural health condition monitoring of large-span spatial structures. First, this study proposes a structural response reconstruction technique for reconstructing key response information using a small amount of measurement information. Considering the model and measurement errors, the structural response reconstruction technique is investigated, and a reconstruction measurement theory with multiple types of sensors is proposed for practical engineering to meet the requirements of deformation monitoring. Through several simulation experiments, the results show that the reconstruction method proposed in this study achieves a better result in reconstruction accuracy than the traditional reconstruction method. In addition, the optimal layout of sensors is also a key issue for health monitoring, and this article proposes optimizing the layout of strain sensors and accelerometers using an improved genetic algorithm. The results of simulation experiments show that the number of strain sensors and accelerometers is reduced by half by this optimization method, which greatly reduces the cost and has a certain guiding significance for practical engineering.

Antenna design and optimization must ensure robust electrical performance, making its analysis a crucial step in all antenna design processes. Traditionally, this analysis involves setting up various cases after establishing the calculation model, comparing the performance of each case, and summarizing the impact of relevant factors to guide design and optimization. However, this method is time-consuming and inefficient. This paper proposes a sensitivity-based approach for analyzing antenna electrical performance, using a radome-covered array antenna as an example. First, we derive the formulas for calculating the antenna’s electrical performance and its sensitivity to the current amplitude, array element position, and radome thickness. We then design comparative experiments to analyze the antenna’s performance using the sensitivity-based method and the traditional case enumeration method. Comparing the conclusions of both methods, we find that they yield the same results regarding antenna performance. The proposed sensitivity-based method offers a quantitative evaluation of various influencing factors and provides a more scientific and systematic approach to analyzing antenna electrical performance.

The use of cold plates is often considered a preferred cooling strategy to quickly remove detained heat from inside the system, which is widely used in engineering applications such as battery thermal management systems (BTMSs). Structural designs are essential to cold plate designs and serve as the foundation for other subsequent designs. This study introduces a free-shape modeling method for the structural design of cold plates with tree-like channels. The geometric characteristics include tree-like features (branching angles, lengths, numbers, and levels), passage patterns, elliptical cross-section sizes and shapes, and channel twists. They can all be freely revised by adjusting the related control parameters. A case of Cold Plates with Tree-like and Straight Channels (CPTSC), which is frequently found in BTMSs, is designed to verify the universality and effectiveness of the proposed free-shape modeling method. After that, the optimization technology based on the NSGA-II evolutionary algorithm is used to minimize the average temperature (overall thermal performance) and root mean square temperature (temperature uniformity) of top and bottom surfaces. The generalized minimum residual (GMRES) method is utilized for the numerical analyzes, and the numerical results indicate that the resulting designs can reduce the average temperature and root mean square temperature by up to 5.91 K (1.75%) and 2.06 K (23.54%), respectively, for Re=1000 and a total power of 600 W. The numerical and experimental results show that the structure of the best compromised solution reduces both thermal indicators by 5.79 K (1.72%) and 1.88 K (21.49%), respectively. This work provides a guideline for the design of tree-like structures that can be used not only in flat-panel cold plates but also in disk-shaped cold plates, heat sink with fins, and heat sink filled with phase change materials.

Active phased array antenna (APAA) is a representative of complex electronic equipment, and it plays significant roles in scenarios such as battlefield situation perception, aviation guidance, and communication. It has become the core equipment in land, navigation, and aeronautical applications. With the continuous improvement of technical changes and military requirements, the working frequency band, pointing accuracy, gain, and low sidelobe level of APAA increase, and the multi-disciplinary design contradiction between antenna electrical performance and structure and temperature becomes increasingly prominent. As a result, the electrical performance of APAA in service is prone to be affected by the external complex environments. The structural-electromagnetic-thermal (SET) coupling problem has become a key problem restricting the development of APAA. This paper has summarized the structural features and environmental loads of advanced APAA on different platforms and provided design basis and principle for antenna designer. And then the SET coupling theory of APAA has been introduced, which can be applied in both the design and manufacturing stage, as well as the performance control technology in service environment of APAA. This theory helps to analyze the impact of environmental factors, such as antenna structure deformation, radome high-temperature ablation, and feed errors, on the antenna's performance. For 128 × 768 spaceborne array antenna, in the range of 25∼85°C, the gain of antenna decreases with the increase of operating temperature and decreases by 0.015 dB with each increase of 1°C. The key design parameters in the fields of antenna manufacturing accuracy, efficient heat dissipation, and lightweight design are also analysed; for 32 × 32 rectangular planar phased array antenna, the gain of antenna decreases by 2.715 dB when the random error of installation position in x, y, and z direction reaches 1/10 of the wavelength. In addition, condition monitoring, displacement field reconstruction, and electrical performance compensation of APAA have also been touched to help engineers maintain and guarantee the antenna performance throughout its life cycle. Finally, the future research direction of SET technology of APAA has been discussed, and SET technology is extended to more fields such as antenna parameter uncertainty, high-frequency circuit electronics manufacturing, and electronic equipment performance guarantee.

有源相控阵天线广泛应用于地面防空、机载火控、弹载制导、空间通信、电子侦察、气象导航等领域,是未来雷达技术发展的主流.天线在服役过程中不可避免地会受到复杂环境载荷作用,使阵面产生难以预知的结构变形与馈电误差,导致阵元位置偏移、指向偏转、阵元间互耦改变等,最终严重恶化天线的电性能.为此,文中归纳了陆、海、空、天不同服役场景下的环境载荷因素,厘清了稳态载荷、瞬态载荷对天线性能的影响机理,总结了天线阵面形变与馈电系统误差监测方法,进一步从结构补偿、电子补偿两方面给出了天线性能调控关键技术,并探讨了有源相控阵天线服役性能调控未来的研究方向与挑战.

The next-generation communication base station antennas represented by phased array antennas are towards high frequency, high gain, high density, and high pointing accuracy. The influence of mechanical structure factors on communication system channel quality is obviously increasing, and the electromechanical coupling problem is becoming more prominent. To effectively guarantee the realization of 5G/6G communication in complex working environments and accelerate the commercial process of future communication systems, an electromechanical coupling channel capacity model is established in comprehensive consideration of the positional shift, attitude deflection, and temperature change of the communication base station phased array antennas. It can be used to rapidly evaluate the communication index degradation of RF devices within the heating environment. Moreover, a sensitivity model of the electric field strength and array antenna channel capacity to the random position error of each element is constructed. The influence of the random positioning error of each element on the communication indicators is analyzed and compared under different working conditions. The simulation results show that the proposed model can effectively provide a theoretical basis and guiding role for the design and manufacture of high-frequency array base station antennas.

Thermal load causes the structural deformation of the spaceborne active phased array antenna (APAA), which could degrade electromagnetic performance of antenna. The phase com-pensation method and the amplitude-phase compensation method based on the least square method are applied to compensate the electrical performance of the deformed antenna under obtaining the excitation adjustment of antenna elements. Taking the $24 \times 32$ element microstrip array antennas designed in this paper as an example, the compensation effects of the two methods on different observation areas of the antenna are analyzed, which provides a theoretical direction for ensuring the electrical performance of spaceborne APAAs.

The application of intelligent algorithm in reconfigurable antenna design can break the inefficiency of traditional antenna design based on engineering experience and electromagnetic simulation software and can significantly improve the intelligent level of antenna design. However, the convergence rate, global search ability, and optimization accuracy of the intelligent algorithm seriously restrict the accuracy and automation efficiency of antenna design and have become the bottleneck of reconfigurable antenna rapid intelligent design. Therefore, an adaptive immune annealing algorithm (AIAA) for rapid design of reconfigurable antenna is proposed in this article. AIAA introduces the idea of adaptive crossover and mutation into the basic immune algorithm (IA), which improves its population update strategy and improves the convergence rate of the algorithm; moreover, simulated annealing (SA) operator is added to the improved IA, which enhances the global search ability of the algorithm. The standard function test results show that compared with the basic IA, AIAA improves the convergence rate, global search ability, optimization accuracy, and robustness. Finally, based on AIAA, a design scheme of frequency and pattern reconfigurable antenna is proposed. Frequency reconfigurable antennas with resonant frequencies of 8.58 GHz ( $X$ -band) and 15.83 GHz (Ku-band) and pattern reconfigurable antennas with maximum radiation directions of +39° and −39° in the xoz plane are designed based on this design method, and experimental tests are carried out. The accuracy and effectiveness of the AIAA in the design of reconfigurable microstrip antenna are verified.

In this article, the efficiency of the robust design methods for large array antennas with the simultaneous presence of interval amplitude, phase excitation errors, and antenna position errors is addressed. The CPU time for a single iteration of the robust optimization method is greatly reduced by the proposed prior knowledge-based algorithm (PKA). Mathematically, the array factor bounds of array antennas with interval uncertainties can be taken as the bounds of the modulus of the sum of the complex intervals with both the modulus and argument errors (CIMAS). The PKA for the modulus of CIMAS consists of three theorems: 1) the necessary conditions for each complex interval for the upper modulus bound of CIMAS; 2) the method for judging whether the lower modulus bound of CIMAS equals zero; and 3) the necessary conditions for each complex interval for the nonzero lower modulus bound of CIMAS. The efficiency and accuracy of PKA are demonstrated by comparisons with two popular methods. Based on genetic algorithm (GA) and PKA, the robust designs of array antennas under multiple constraints are also presented.

Secondary shape optimization for topological boundary is proposed to further improve heat dissipation performance of cold plates. Firstly, the topological boundaries obtained with topology optimization are fitted parametrically by Bezier curves. Here, considering the numerical complexity caused by Bezier curves characters, a simple process is introduced. Thereafter, three algorithms are proposed to formulate secondary shape optimization. The proposed algorithms can further qualitatively handle explicit geometry boundary through optimizing the coefficients of the established distance function or the control points of Bezier curves. The effectiveness of the proposed algorithms is subsequently verified by analyzing the 2D and 3D models given after topology optimization and the obtained results show that these approaches further provide well-performing cold plates design. These approaches provide a theoretical basis for engineering application and they are easy to be processed and implemented. The proposed approaches can be applied not only to the problem of conjugate heat transfer but also to the problems of pure heat conduction, continuum structure, even other more complicated engineering structures.

MEMS phase shifter has many advantages as the steering wheel' of phased array antenna beam steering. The deformation of mechanical structures of MEMS phase shifter influenced by the complex environmental factors, which became the biggest obstacle to further enhance the performance of phased array antennas. The electromechanical coupling model between the bridge height and phase shift of the distributed MEMS phase shifter is developed. The coupling model could be used to predict the phase error and determine the bridge height tolerance for the deformed MEMS phase shifter. The simulation results of four-bit distributed MEMS phase shifter with 15 bridges illustrate the validity of coupling model and demonstrate the application potential for engineering design and test.