Simone Montori

A Transportable Reflectarray Antenna for Satellite Ku-band Emergency Communications

The design of a Ku-band reconfigurable reflectarray antenna for emergency satellite communications is presented. Bidirectional high data rate satellite links are needed in emergency conditions where other telecommunication infrastructures are not available. In order to operate in this type of scenario, an antenna should be deployable, transportable, and easily repointable. The need of an automatic and fast satellite location and pointing system leads to a completely electronic reconfigurable antenna. The operative bandwidth is from 10.7 to 12.5 GHz for reception and from 14 up to 14.5 GHz for transmission (30% of relative bandwidth). The selected antenna architecture is based on a dual reflectarray system comprising a passive subreflectarray and an active main reflectarray made of reconfigurable 1-bit elementary cells based on PIN diodes.

Accurate FMCW radar-based indoor localization system

An accurate ranging system based on FMCW (Frequency Modulated Continuous Wave) Radar is presented. The system ensures a centimetre precision even in environments with high multipath, such as warehouses packed with metallic objects or extremely dusty sites where conventional RF, laser, ultrasonic or video technologies present severe limitations. The proposed solution has been experimentally applied in Automatic Guided Vehicle for warehouses. The architecture of the system and the obtained results are presented in detail.

A 77 GHz Near-Field Probe with Integrated Illuminating Waveguide used for Reflectarray Characterization

Abstract In this paper, a near-field probe with integrated illuminating waveguide for frequencies around 77 GHz is introduced. For such high frequencies, alignment of transmitter and receiver probes in the near-field measurement setup are difficult. So the purpose of this work is to integrate both devices into one setup for an easy and reproducible measurement procedure. The measurement probe is used to characterize individual patches on the surface of reflectarray antennas, placing the device a few millimeters above the antenna surface. This requires a high spatial resolution and a insignificant influence of the probe on the examined structure. The ability of the developed probe has been investigated in simulations and verified in near-field measurements at reflectarray structures for 77 GHz. In this extended paper version, the setup is used to investigate a test-array with polarization twisting elementary cells and the lower reflector of a folded antenna, whose characteristics are based on a bifocal design process.

1-bit RF-MEMS-reconfigurable elementary cell for very large reflectarray

This paper presents a reconfigurable MEMS based radiating element for the realization of a beam steering reflectarray. The elementary cell consists of a square patch slotcoupled to a phase shifting circuit with 1-bit phase resolution (0°/180°), operating at 76.5GHz. Reconfigurability is obtained with RF MEMS switches integrated in the elementary cell. The problem of reconfigurability of reflectarray antennas based on RF MEMS technology is addressed within the European FP7 project called ARASCOM. Since thousands of reconfigurable elementary cells are employed, reducing the number of tuneable components is of fundamental importance for the practical realization of the reflectarray. A dramatic reduction of the number of tuneable devices is shown to be achievable without performance degradation by a proper architecture based on 1-bit digital phase shifting. In this paper the elementary cell design and the reflectarray fabrication technology are illustrated in some details showing the feasibility of the proposed approach.

RF MEMS-reconfigurable architectures for very large reflectarray antennas

The problem of very large reconfigurable reflectarray (RA) antennas based on RF MEMS technology is addressed in connection with a 77 GHz RA for imaging application being developed within the European FP7 project called ARASCOM. Since thousands of reconfigurable elementary cells are employed, reducing the number of tuneable components is of paramount importance for the practical realization of the reflectarray. A dramatic reduction of the number of tuneable devices is shown to be achievable without performance degradation by a proper architecture based on 1-bit digital phase shifting and on the separable illumination of the RA. The elementary cell design, the fabrication technology and the control network architecture are illustrated in some detail showing the feasibility of the approach proposed.

MEMS and combined MEMS/LC technology for mm-wave electronic scanning

This paper proposes two innovative solutions for the exploitation of MEMS and Liquid Crystal (LC) technology in mm-wave electronic scanning reflectarrays: a MEMS-only approach, where the switches are used to obtain reconfigurable elementary cells with 1-bit of phase resolution and a LC/MEMS combined solution, able to provide a continuous phase-shift up to 180°.