A Method of Synthesis for Multi-Frequency Smart Antenna Arrays for Coastal Monitoring

Thanks to their versatility, smart antenna arrays are used in a wide variety of contexts, including, in particular, coastal monitoring. Within this framework, operating in multi-frequency modality might reveal a fundamental requirement. So, in this paper the problem of synthesis of multi-frequency antenna arrays is addressed. Precisely, a fixed grid array is considered, having an arbitrary but known geometry. The excitation vectors are optimized in such a way that the radiation patterns belong to a prescribed mask at certain assigned frequencies. Moreover, in order to have a simpler, cheaper and more efficient antenna, the phase-only synthesis is performed. In fact, thanks to this requirement, variable attenuators are not necessary and only phase-shifters are used in the feeding network. Numerical examples are provided, which validate the effectiveness of the method.

I. Introduction

The metrology of the sea involves social, economic and environmental aspects of our everyday lives. Thus, the research in the field of metrology for marine environment attracts the interest of national and international institutions, both from industries and governments, as well as from academia. Within this framework, real-time monitoring of the sea and in particular of the coasts is of great importance in many applications, ranging from the protection of coastal environment, to home-land security, from the monitoring of fishery to the detection of oil spills, just to name a few. This is why nowadays, the importance of coastal monitoring is universally recognized, so that many research programs have been proposed and funded worldwide during the last decades to achieve the so-called ‘marine awareness’ [1]–[6].