HF & VHF propagation over an irregular interface with impedance discontinuities – PROPHETE

PROPHETE aims to develop and validate a prediction tool for radiation and propagation for HF and VHF antennas. These calculations are usually performed by different tools. In this project they will be merged into one single tool. PROPHETE will allow predicting the far field pattern of an antenna located over an irregular terrain in a complex environment. It will allow in particular estimating the transmitted field after propagation across an earth – sea path including terrain irregularities. This kind of development is of primary importance to qualify HF surface wave Radars. PROPHETE will help users assessing the radar performances considering the environment. Such a product does not exist today and its need has been clearly identified.

The new topics that will be addressed in this project are:

• To characterize the near field of HF and VHF antennas
• To characterize the radiated far field : sky wave and ground wave
• To quantify the sky and ground waves radiated powers
• To calculate the field propagated over an irregular terrain with impedance discontinuities (earth – sea) and roughness

Each one of these different points has been addressed previously. In some cases freeware tools are available. Solutions are usually restricted solutions. The novelty of this project is to build a global model for arbitrary antennas in a complex environment and with no restricting hypothesis. A more detailed analysis and the improvements that will be carried out with respect to existing solutions are presented at chapter 2.3

This study has several objectives

• To improve, develop and validate innovating calculation techniques
• To perform a global calculation and validate the results obtained
• To perform budget link calculations for antennas located in a complex environment both for sky wave and ground wave
• To investigate new trends for budget link improvement in one particular operating mode

This study is related to radar applications (over the horizon and surface wave radars) and telecommunications in this frequency band. Needs have been identified both for civil (coastguards, ships routing, …) and military applications (telecommunications and radar).

The project includes theoretical work, algorithms development and measurements. These lasts will be performed at several stages of the study and will allow to validate the obtained results for specific cases.

This work will benefit from previous work experience at L2E – UPMC (Luca Petrillo and Nicolas Payet thesis in collaboration with ONERA), at XLIM (propagation , GPR, and RCS software development) and at IEEA (antennas and propagation software development).

This project is dedicated to thematic axis N°3 : acoustic and radio electric waves under topic 2.3.1 : radiation generation and measurements, antenna and field measurements and topic 3.2 propagation, earth links, sky wave and ground wave, reflection diffusion over the terrestrial surface.