The state mobile parks are very heterogeneous (cars, trucks, buses, tractors, equipment, etc.) with a wide variety of brands. This makes maintenance and drain management more complicated and costly. An adequate solution is proposed in this article not only to facilitate maintenance management but also to optimize its cost. It is based on a passive sensor that evaluates the condition of the lubricant, detects its degradation, and indicates the optimal timing for replacement. This information is displayed directly on the vehicle’s interface. Moreover, it is sent wirelessly through an RFID network to the maintenance team responsible for the fleet. This team ensures real-time supervision and quality assurance of the lubricants across multiple vehicles simultaneously. Tracking the condition of the lubricant for each vehicle in the fleet provides accurate drainage intervals. This extends the durability of the lubricant and filters, resulting in significant savings in resources, labor, and operational costs. Additionally, it greatly simplifies the coordination of maintenance schedules. The development of this device is straightforward and cost-effective. It comprises a bifilar line, symmetrical and open at one extremity. It operates in the UHF frequency range. Measuring its input impedance while submerged in the lubricant allows for the direct calculation of the lubricant’s dielectric constant, which changes as it deteriorates.

Abstract-In this work, we present an innovative, simple, and accessible approach to capturing radio waves from the galactic continuum-ubiquitous on Earth-within a laboratory setting. The proposed solution allows students, educators, and enthusiasts-who may not have access to traditional radio telescopes-to engage with radio astronomy through a hands-on, cost-effective method. Unlike previous systems that require complex SDR programming or custom-built receivers, our design employs a basic λ/4 wire antenna connected to a reconfigurable spectrum analyzer-equipment commonly available in many teaching laboratories. This makes the setup immediately applicable for practical instruction.Our main contribution is to demonstrate that such a simplified configuration can reliably detect known signals from the galactic radio continuum. Measurements were conducted across several frequencies and compared with data from the literature, showing strong consistency and validating the system’s performance. The device functions as both a scientific instrument and an educational platform, helping democratize access to radio astronomy and fostering scientific curiosity in academic settings.By integrating all components into a unified laboratory environment (Radio Telescope-Lab), this work offers a reproducible and scalable solution that bridges the gap between advanced research instruments and accessible educational tools.

This work presents the design of a novel hybrid controller topology for the biasing and protection of GaN HEMT transistors in radio frequency (RF) power amplifiers. These high-electron-mobility transistors require dual power supplies with opposite polarities, making their management and protection challenging, particularly when relying on manual sequential biasing. The proposed controller, built on the STM32 platform, optimizes the regulation of transistor temperature, drain-source voltage Vds, and drain current Id. It ensures precise biasing control and proper sequencing during the power-on and power-off cycles of the RF power amplifier. At startup, an integrated dichotomy algorithm dynamically adjusts the gate-source voltage Vgs, enhancing operational stability and efficiency. By improving transistor control and reliability, this approach mitigates rapid degradation, thereby reducing manufacturing costs and accelerating the commercial adoption of GaN HEMT power amplifiers.

In this work, we have presented a new and very simple original approach to capture, in the laboratory, the radio waves coming from space and which exist everywhere on Earth (radio waves emitted by celestial bodies). This approach will certainly attract new researchers, students and amateurs, interested in radio astronomy and who do not have a radio telescope. Therefore, it allows them to deepen their knowledge in this rather vast and delicate field and participates in future advances in radio astronomy. For them, we have presented here this new approach which is very easy to implement compared to current radio telescopes, whose construction requires a lot of money, time and special skills. It can also be used as an educational tool for universities and colleges aiming at teaching astronomy. The measuring instrument developed in this work is based on a simple wire antenna of length λ/4 and a spectrum analyzer, which is a very sensitive and reconfigurable superheterodyne receiver. The measured results were compared with those of the literature and we concluded that they are in good agreement, which validates this original approach where the antenna and the receiver (Radio telescope) are found together inside the measurement laboratory (Radio Telescope-Lab).

This manuscript presents the design of a low noise amplifier (LNA). It's used to improve the performance of a new original approach, allowing to characterize, in the laboratory, the radio waves emitted by 21cm neutral hydrogen atoms. these last coming from our galaxy, to the earth, with a very low power. The new measurement approach used is original since it consists of a spectrum analyzer, two low-noise amplifiers placed in cascade and a simple antenna of length λ/4. This measuring instrument is easy to implement compared to current radio telescopes, the construction of which requires a lot of money, time and special skills. This approach can also be used as an educational tool for teaching astronomy at university. The measured results were compared with those of the literature and are in good agreement, which validates the new measurement approach used.