Low-profile Steerable Antennas for User Terminals

We present an innovative solution for a low- profile antenna with mechanical beam steering capability in a wide angular range, within a large bandwidth. The device has been conceived for next generation SATCOM communication in the Ka-band from user terminals on board moving platforms. It consists of a fixed primary feed and two rotatable metalens deflectors, which exploit the Pancharatnam-Berry phase effect to steer the beam. Experimental results performed on a fabricated prototype showed how the proposed design is able to effectively scan the beam with low grating lobes across the full field of view, with a scan loss in line with other flat solutions.

I. Introduction

The demand for high data rate mobile communications has continuously increased in the last years and a massive expansion of mobile satellite terminal market into new domains is expected in the future. The beam steering antenna is the main cost item of a mobile satellite terminal. However, the established beam steering antenna architectures cannot meet all the requirements of many new civil markets, such as low cost, low power consumption, and low profile. This latter requirement is very important to reduce drag and fuel costs for vehicles. As a matter of fact, antennas based on an electronic scanning can be very low profile, but they are still too complex and expensive, power hungry and subject to thermal issues. On the other hand, conventional mechanically scanning reflectors are too heavy, bulky and fragile for this application. Multi-panel antennas represent a hybrid solution that alleviates the problem of losses and allows for an important thickness reduction, but they might suffer from panel shadowing and/or pattern degradation for low elevation angles. Therefore, various efforts have been recently carried out to conceive different approaches for beam scanning.