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The promises made by the Microwave Photonics (MWP) in the last 25 years are becoming reality in devices and systems that use the optical carrier in radar and EW applications. This article aims to define new architectures and approaches for the adoption of fiber optic functionalities and technologies to radar and EW, moreover it aims to review the results achieved in prototypes and actual products, both at subsystems and system level, also highlighting the findings in terms of limitations and needs for further development.

In this work we present the development of a Carbon Nanotubes based multifinger microtriodes. Such device represents a viable and optimized alternative to the standard Spindt-type microtriode. The main improvement of the multifinger geometry consists on the possibility to reduce the cathode-grid capacitance by reducing the overlap between the two electrodes using a parallel patterning of the metallic lines. This approach allows doubling the cut-off frequency of the devices with respect to the Spindt-type triode. The prototype multifinger triode has been realized and field emission properties have been measured.

In the framework of development of architectures and components for advanced modulation schemes a novel approach for Single Side Band modulation has been proposed and the device has been realized and tested. It provides numerous advantages with respect to already proposed approaches, in term of design complexity and reduced need for external components (phase shifters, beam splitter) for pre-processing of the RF signal to be fed to the modulator. Results of fabrication and preliminary characterization of the device are presented

This paper describes the status of the OPTHER (OPtically driven TeraHertz AmplifiERs) project and progress toward the THz amplifier realization. This project represents a considerable advancement in the field of high frequency amplification. The design and realization of a THz amplifier within this project is a consolidation of efforts at the international level from the leading scientific and industrial European organizations working with vacuum electronics.

THz applications require sources and amplifiers compact, lightweight and powerful. Vacuum electron devices are the candidate solution. Among others, the Corrugated Waveguide Slow-Wave Structure seems particularly suitable for Traveling Wave Tubes in the THz region. THz vacuum electron devices require high precision technological processes with high aspect ratio such as SU-8 process. However, fabrication tolerances could highly affect the overall performances. Therefore a statistical analysis is fundamental for a reliable design. In this summary it is proposed a method based on an analytical model of the corrugated waveguide together with the Pierce theory, to fastly compute the gain of corrugated waveguide vacuum traveling wave tubes. The method is validated by three-dimensional electromagnetic softwares, both for cold and hot parameters. The proved accuracy and fast computation time make the model suitable for performing the sensitivity analysis of the Corrugated waveguide Vacuum tube to be realized by SU-8 technology process.

The European project OPTHER - Optically Driven THz Amplifiers, is focused on the realization of a THz amplifier. This device aims to overcome the actual limitations of THz sources in terms of emitted power, opening the way to the use of THz in monitoring security systems. Two alternative schemes are under study for amplification. In the first one (THz drive signal amplifier) the continuous wave electron beam emitted by the CNT cathode is modulated by the electric field in the interaction structure driven by a THz signal (generated by QCL or laser mixing). In the second one (optically modulated beam THz amplifier), the CNT cathode emits bunches of electrons at the THz rate. Those bunches are transmitted to the interaction structure and generate the amplified output signal.

Active phased array antennas in state-of-the-art radars, adopt many high power amplifiers. High power transmit-receive modules are assembled in dense electronic environments and have to cope with severe environmental operative condition. Radar state-of-the-art systemic signal processing requires growing and enormous power calculation in order to obtain unprecedented hard real-time performances as well as implementing adaptive knowledge-based algorithms. Unfortunately, the present steady growth of the micro-processors performance are reaching a saturation point due to the approaching limit of miniaturizations. Present and future active phased array antennas and signal processors have large and increasing heat dissipation problems. Nanotechnologies are emerging as enabling technologies that will provide a revolution in the sectors of sensors and radar systems. These innovative technologies could enable new solutions and improve weight, size, speed, power consumption, efficiency, and so on. In addition, the nanotechnologies could solve the increasing heat dissipation problems by adopting Carbon NanoTubes CNT ropes or arrays for thermal management and interconnection.

Here we report the fabrication and the testing of a quartz crystal nanobalance (QCN ) microsensor assembled using single-wall carbon nanotubes dispersed in a polymer matrix. The sensor was used for NH3 detection. The good performances of this sensor, characterized by a detection limit of 1 ppm and by fast response times , are compared with those of a resistive sensor assembled using the same SWNTs The research is aimed at combining different sensing devices based on carbon nanotubes for manufacturing a lab-on-chip hybrid system.

A new challenging solution for an high power (75 W) module package (52mm times 52mm times 38mm) for radar application has been developed. The described module is integrated in a 3D package with an RF vertical interconnection and an embedded heat-pipe cooling system. This integrated solution will permit a lower junction temperature for the high power component compared with traditional ones

An original heterodyne modulation scheme is presented for generating tunable local oscillator signals. A dual-frequency laser has been cascaded with a frequency shifters to down or up convert RF signals in the range 0.2-32 GHz.

The authors investigate the design and performance of a nonisolated inverter. The inverter is designed to be powered from a bipolar photovoltaic array series-parallel combination. The array is configured so that its output is compatible with the input of the inverter. The load circuit return is common with the input power return. The inverter control circuit utilizes direct feedback pulse-width-modulated (PWM) control. A signal with a triangular carrier wave is compared to a reference sinusoidal modulating wave to determine the switching instants. This technique is easily implemented using analog circuits. The control and power processor circuits consists of several subcircuits. These subcircuits are described. >