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An optimisation framework for near field multifocusing on antenna arrays is proposed. Its aim is to obtain the feeding weights that must be applied to the elements of the array so that the antenna focuses on two or more targets simultaneously. The method is based on the definition of a proper cost function, which is minimised using an optimisation algorithm over an equivalent least squares problem. The success of the technique is noted in the fact that different array parameters can be obtained: magnitude and phase of the array elements or only phase synthesis. In order to show the efficiency of the method, several tests are carried out using different arrays and optimisation parameters. The simulation, manufacture and measurement of an 8 × 8 planar array able to focus on two different targets is also performed. Results show how the framework can be applied to general arrays and demanding requirements, so it may be easily extended to different synthesis problems besides multifocusing.

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Abstract-A new efficient method for broadband antenna characterization from phaseless acquisitions in the frequencydomain is presented. The phase-retrieval technique is based on an extrapolation of the off-axis indirect holography. In common with the conventional approach, the power of the interferometric field of the antenna under test and a reference antenna, whose field is known in advance, as well as the power of the antenna under test alone, is measured at the desired frequencies. Nevertheless, the phase retrieval is accomplished independently at each spatial point by filtering in the time-domain rather than in the k-space. Thus, the dependency of the phase retrieval on the position accuracy is reduced and it can be accomplished simultaneously at all frequencies without resorting to iterative schemes. Moreover, it yields a less dense sampling and a phase retrieval algorithm not dependent on the geometry of the acquisition. The method is illustrated with a numerical example in the W -band as well as with two near-field measurement examples in the Ka-and W -bands.

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In this paper, we propose a ball grid array (BGA) module with integrated 3D-printed plastic lens and dedicated 120 GHz OOK transceiver for 5G Backhaul/Fronthaul applications. The problem to be addressed is the following: 5G future networks will need backhaul/fronthaul 10Gbps wireless links and it's mandatory to design cost-effective and energy efficient solutions. The proposed solution is made of 3D-printed plastic lens antenna and cheap 7×7×0.362 mm 3 BGA module integrating a 2×2 array of aperture-coupled patch antennas as the source of the lens. The measurement results of the full system confirm the expected performance of the plastic lens: a-10dB matching and a 28 dBi realized gain from 114 to 140 GHz. The active measurements allows a Tx/Rx link >12Gbps data transmission with <10-6 BER at nearly 5m. This link is realized with an energy-efficiency better than 1.6 pJ/b/s which is at least 40 times better than state-ofthe-art high-speed existing TRx's. Those promising results pave the way for future cost-effective and low consumption backhaul/fronthaul systems for 5G communications. What is the novelty of your work over the existing work (100 words)? So far, several wireless links at 120 GHz have been deployed by various authors with very high Gbps speed but at the expense of high DC consumption and bulky material which is in turn correspond to weak integration of the full-system. The novelty of our work lies in the fact that every communicating block has been optimized in conjunction with all the other nearby elements, strongly taking into account cost and integration capability. Therefore a Tx/Rx link >12Gbps data transmission with <10-6 BER at nearly 5m. This link is realized with an energy-efficiency better than 1.6 pJ/b/s which is at least 40 times better than state-of-the-art high-speed existing TRx's. Provide up to three references, published or under review, (journal papers, conference papers, technical reports, etc.) done by the authors/coauthors that are closest to the present work. Upload them as supporting documents if they are under review or not available in the public domain. Enter "N.A." if it is not applicable. [1] A.

This paper presents a novel interrogation system that 7 combines multiple millimeter wave transmitters and receivers to 8 create real-time high-resolution radar images for personnel secu-9 rity screening. The main novelty of the presented system is that the 10 images can be created as the person being screened continuously 11 moves across a corridor where the transmitters and receivers, 12 working in a fully coherent architecture, are distributed. As the 13 person moves, the transmitters and receivers are sequentially acti-14 vated to collect data from different angles to inspect the whole 15 body. Multiple images, similar to video frames, are created and 16 examined to look for possible anomalies such as concealed threats. 17 Two-dimensional (2-D) and three-dimensional (3-D) setups have 18 been simulated to show the feasibility of the proposed system. The 19 simulation results in 2-D have been validated using measurements. 20

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