From 1 July 2024 to 4 July 2024 Prof. Ing. Owen Casha attended CODIT 2024, the 10TH INTERNATIONAL CONFERENCE ON CONTROL, DECISION AND INFORMATION TECHNOLOGIES, which was held at the University of Malta Valletta Campus. Prof. Ing. Owen Casha, from the Department of Microelectronics and Nanoelectronics, presented a paper titled “Design and Implementation of a SNMP RF Power Monitoring System for an ATC High Power AM Transmitter”. The work discussed in this paper was made in collaboration with the Communication Technical Services team within the Malta Air Traffic Services Ltd.

This paper presented the design and implementation of a Simple Network Management Protocol RF power monitoring system for a 1.5 kW Air Traffic Control high power amplitude modulation transmitter operating at 122.775 MHz (East Sector). The design is centered around an optimised four port microstrip directional coupler which enables the monitoring of the forward power and the reflected power in the transmitter RF chain. Optimisation was focused on its coupling, directivity and isolation.

The designed dual directional coupler features a measured coupling of -25 dB, a directivity of 41 dB, and an isolation between the forward and reverse coupling paths of around -70 dB, over the air band (118 MHz to 137 MHz). The forward and reflected power signals are converted to low voltage baseband signals via a logarithmic amplifier to enable further processing via a microcontroller platform. The implemented system provides parameters such as the modulation index, forward and reflected power, standing wave ratio and reflection coefficient, via a dedicated Simple Network Management Protocol over a local area network. The proposed system also provides an alarm in case an increase in the standing wave ratio above a certain threshold is detected.