Giuseppe Musacchio Adorisio

This work presents the design and fabrication of a modular stripline series-fed patch antenna (SSFPA) for Ku-band GEO communication in mobility applications. The proposed architecture adopts a modular and scalable approach, in which two 8×16-element tiles are mirrored and combined to form a 256-element array that can be readily reconfigured or expanded to satisfy different system requirements. The feed network, based on a carefully optimized stripline series-fed configuration, enables electronic beam steering in elevation. The present work focuses on the design and experimental validation of the elevation-steering performance, while mechanical integration for azimuthal scanning is left for future development. A prototype of the antenna was fabricated and thoroughly characterized. The measured results show an elevation steering range from 0° to 55°, while stable radiation characteristics are maintained across the full operating band and scanning range. This performance is enabled by the mirrored architecture, which provides improved compensation of beam squint. At the central design frequency of 11.7 GHz, the proposed phased-array antenna achieves a measured gain of 23 dBi, with a maximum gain reduction of approximately 4 dB over the considered steering range at this frequency.

We describe an antenna measurement system that uses a cable-suspended system to move the probe antenna around the antenna to be characterized. Radio frequency data and pose data are acquired during the flight and processed later to derive the antenna radiation pattern. The post-processing leverages equivalent currents to deal with scattered data in an efficient way. We give details on the implementation of the measurement system and present results when reference antennas at 6 GHz and at around 1.25 GHz are measured, to show the system performance.

Oncological microwave hyperthermia is a clinically proven sensitizer of radio- and chemo-therapies; it acts by selectively increasing the temperature of tumor cells by means of antenna applicators. Its current limitations mostly come from the inability to reliably predict, and hence control, temperature inside the patient during treatment, especially for deep-seated tumors. Simulations are employed in treatment planning, but due to related uncertainties invasive thermometry is necessary, usually via catheters. Being invasive, their use must be minimized and provides very limited spatial information. Here, we demonstrate an approach to obtain 3D temperature information in real time from few measurement points via massive use of high-performance simulations carried out prior to treatment. The proposed technique is tested both in a fully anthropomorphic in-silico scenario, and in an experimental controlled setting. The obtained results demonstrate the potential of the proposed method as a low-cost real-time temperature monitoring technique in cancer hyperthermia. Use with intra-luminal, minimally-invasive catheters is supported by the positive outcome experimentally obtained using data points directly acquired in the trachea-mimicking phantom structure.

Objective: Microwave hyperthermia is a clinically proven cancer treatment used in combination with conventional therapies to enhance the overall treatment outcome. It consists in selectively increasing the temperature of tumor cells to 40–44 °C by means of electromagnetic fields that are externally generated and coupled to the patient body via antenna applicators. The primary goal is to shape the power deposition (specific absorption rate, SAR) with focusing on the tumor region, and minimizing the risk of hotspots in the surrounding healthy tissues. Methods: For non-superficial tumors, phased-array antennas are used to focus the energy on the tumor. Finding patient-specific optimal antenna feeding coefficients represents an essential step to ensure an effective and safe administration of the heating. In this article, we present a way to optimize the array power transfer effectiveness (impedance matching) that does not deteriorate the spatial power deposition performance. A global optimization approach is adopted, using a cost function properly tailored to incorporate the active reflection coefficients of the array and the Hotspot-to-Target SAR Quotient (HTQ)—the latter being the standard in hyperthermia applications. Results: The effectiveness of the technique is demonstrated in a scenario relevant to the treatment of tumors in the neck region. The results show that our method significantly improves antenna matching without compromising the HTQ, achieving values within the recommended limits. The performance of the proposed approach is also experimentally tested with full heating in a corresponding phantom. Conclusions: This study introduces an optimization approach that enhances phased-array antenna performance for hyperthermia treatments without affecting spatial power deposition.