The influence of complex environments such as high temperature and high humidity on the performance of microwave functional components splitter is multi-dimensional, involving multiple levels such as material properties, structural stability, and electrical parameters. The interaction of these factors may lead to the attenuation or even failure of the equipment function. Therefore, it is necessary to deeply analyze the impact path from the perspective of physical mechanism and engineering design.
The direct impact of high temperature environment on microwave functional components splitter is first reflected in the thermal expansion effect of materials. The interior of microwave functional components splitter usually contains a variety of materials such as metal conductors, dielectric substrates, and semiconductor devices. There are differences in the thermal expansion coefficients of different materials, which may cause stress deformation between components under high temperature. For example, gaps appear between the metal cavity and the dielectric substrate due to the mismatch of expansion coefficients, which will change the characteristic impedance of the transmission line, cause the signal reflection to intensify, and the standing wave ratio to deteriorate. At the same time, high temperature will accelerate the aging of semiconductor devices (such as isolation resistors in power dividers), causing their resistance values to drift, destroying the balance of power distribution, and even causing a decrease in isolation and signal crosstalk between adjacent ports. In addition, high temperature will soften the solder at the welding point, which may cause the components to fall off or poor contact, affecting the continuous transmission of microwave signals.
The challenge of high humidity environment mainly comes from the degradation of electrical performance caused by water vapor penetration. When the ambient humidity is high, water vapor may enter the distributor through the packaging gap, adsorb on the surface of the dielectric substrate or penetrate into the porous material. After the dielectric material absorbs moisture, the dielectric constant and loss tangent value will increase significantly, resulting in increased transmission loss of microwave signals, especially in the high frequency band, this effect is more obvious. For distributors with microstrip line structure, the thin water film formed by water vapor on the surface of the conductor will change the effective dielectric constant of the transmission line, causing the characteristic impedance to deviate from the design value, causing signal reflection and uneven power distribution. In addition, long-term humidity may cause corrosion of metal parts, especially contact parts such as joints and reeds. Rust will increase contact resistance, cause signal attenuation or instability, and in severe cases may cause physical disconnection, making the distributor unable to work properly.
The synergistic effect of high temperature and high humidity will further aggravate the performance deterioration. In an alternating hot and humid environment, the internal materials of the distributor undergo repeated thermal expansion and contraction and moisture absorption and dehumidification processes, which may cause fatigue damage. For example, microcracks appear at the junction of the dielectric substrate and the metal shell due to repeated stress of thermal expansion and contraction, providing a channel for water vapor penetration, forming a vicious cycle of "moisture absorption-expansion-cracking-re-moisture absorption". At the same time, the hot and humid environment provides conditions for the growth of microorganisms. The organic acids secreted by molds may corrode metal and dielectric materials, destroy the insulation performance, and cause the leakage current to increase or the breakdown voltage to decrease. This multi-factor coupling effect will cause the performance indicators of the microwave functional components splitter (such as insertion loss, isolation, and standing wave ratio) to deteriorate nonlinearly over time, seriously affecting the reliability and service life of the equipment.
Different types of microwave functional components splitters are affected to different degrees by complex environments. For example, the thermal stability of the resistor and the thermal conductivity of the dielectric block at high temperature become key influencing factors due to the internal integration of isolation resistors and dielectric blocks in the Wilkinson power divider; while the T-type power divider has a relatively simple structure, but the contact reliability at the joint is more susceptible to influence in a hot and humid environment. For integrated multi-layer planar power dividers, the moisture absorption characteristics of the interlayer dielectric and the corrosion resistance of the metallized vias are design difficulties. The thermal stress of multi-layer materials at high temperatures may cause interlayer peeling and damage the signal transmission path. Therefore, in engineering applications, it is necessary to optimize the material selection and structural design according to the type of distributor and the use environment.
In order to cope with the influence of complex environments, multiple protection measures are usually adopted in engineering practice. In terms of material selection, high temperature resistant and low moisture absorption dielectric materials (such as polytetrafluoroethylene glass cloth boards) and corrosion-resistant metals (such as gold-plated or nickel-plated copper alloys) are preferred, and surface coating technology (such as parylene coating) is used to improve the moisture and corrosion resistance of the component surface. In terms of structural design, a fully sealed metal cavity package is used, combined with an epoxy resin potting process to block the water vapor intrusion path, while optimizing the heat dissipation path, and heat is exported through thermal pads or heat pipes to reduce the internal operating temperature. At the circuit design level, a temperature compensation network is introduced to offset the impact of temperature changes on electrical parameters through adjustable components or automatic adjustment mechanisms, while humidity redundancy is reserved to ensure that performance indicators can still be met in high humidity environments.
Long-term reliability verification is an important part of evaluating the impact of complex environments. The actual use environment is simulated by high temperature aging tests and damp heat cycle tests (such as high temperature and high humidity tests conducted in accordance with GJB 150 standards), and the insertion loss, standing wave ratio and other parameter changes of the distributor are monitored in real time using equipment such as vector network analyzers. Test data show that after a distributor without protection design continues to work for a certain period of time in a high temperature and high humidity environment, the insertion loss may increase by several decibels and the standing wave ratio may increase by more than 50%, while the performance fluctuation of the distributor with optimized design can be controlled within a smaller range. These test results provide data support for improved design and promote the stable application of microwave functional components splitter in harsh environments such as aerospace and communication base stations.
In short, the impact of complex environments such as high temperature and high humidity on the performance of microwave functional components splitter is the result of the combined action of physical and chemical effects, involving multiple disciplines such as material science, thermal design, and electromagnetic compatibility. Through the comprehensive application of material innovation, structural optimization and protection technology, combined with strict environmental adaptability testing, the reliability of the distributor in complex environments can be effectively improved, enabling it to maintain stable power distribution performance in scenarios such as communications, radar, and electronic countermeasures, laying the foundation for the overall performance of the microwave system.
