Microwave

Microwave-assisted heating (MWH) has established itself as a transformative and energy-efficient paradigm for advanced materials processing. This review provides a comprehensive overview of the advances achieved at the CNR-SCITEC laboratories in Genoa. In this context, a customized microwave platform has been strategically employed for the synthesis, sintering, foaming, and melting of diverse inorganic, organic, and hybrid systems. The spectrum of materials investigated includes superconducting magnesium diboride (MgB₂), hydroxyapatite-based scaffolds, polyethylene components obtained via microwave-assisted rotational molding, cork-based sound-adsorbing composites, recycled expanded polystyrene (rEPS) panels, and polyvinylidene fluoride (PVDF) piezoelectric films. Across the case studies, MWH demonstrated a superior capacity for reducing energy consumption and processing times while maintaining—or even enhancing—the target functional properties. Furthermore, this work evaluates the technological maturity and emerging market opportunities of microwave-based processing, positioning it as a key and sustainable platform for next-generation materials development.

Continuous-wave magnetrons continue to offer the highest efficiency, lowest cost per watt, and greatest compactness among high-power microwave sources, making them attractive for industrial, scientific, and defense applications. Emerging missions, particularly space solar power systems, industrial microwave heating, and accelerators, demand significantly enhanced performance metrics, including high DC-to-RF efficiency, thermal stability, ultra-low phase noise, and precise phase controllability for coherent operation. To satisfy the critical requirement for high power, low-cost microwave sources with high spectral purity, extensive research has focused on injection-locking techniques, external phase/frequency modulation methods, and large-scale coherent power combining. This paper reviews the fundamental characteristics of CW magnetrons, recent advances in injection-locked magnetron transmitters, power-combining systems employing multiple injection-locked magnetrons, magnetron-based phased-array systems, and emerging applications. Finally, the challenges and promising development directions for next-generation CW magnetrons are discussed.

This work presents a fully integrated, two-stage, deep class-AB power amplifier (PA) operating at a center frequency of 60 GHz. High efficiency and suppression of third-order intermodulation products are targeted, achieving improved linearity compared to reported state-of-the-art designs. A current combining architecture is also employed to enhance the output power capability. The PA is designed in a 22 nm FD-SOI CMOS technology and is optimized through a complete schematic-to-layout design flow. Post-layout simulations indicate that the PA achieves a peak power-added efficiency (PAE) of 28%, a saturated output power ($P_{sat}$) of 20.2 dBm, and a maximum large-signal gain ($G_{max}$) of 19.6 dB at 60 GHz, evaluated at an operating temperature of 60 °C. The design maintains high linearity across the targeted output power range, exhibiting effective suppression of third-order intermodulation distortion (IMD3), which enhances its suitability for spectrally efficient modulation schemes.