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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.

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Millimetre-wave imaging is a powerful non-destructive inspection technique which has become widely used in areas such as through-the-wall imaging or concealed weapon detection. Nevertheless, current systems are usually limited to either a single view point providing a limited 3D millimeter-wave model or a multiview relying on the accurate movement of a robot arm through precise positions resulting in very bulky systems. In this paper, we present a set of techniques to achieve a multiview millimetre-wave scanner. The aperture of the scanner is kept below 16 cm so it can be portable and, consequently, multiview can be achieved by simple hand movements. In addition, optical images are also acquired with a two-fold purpose: i) building a complementary 3D-model by employing Structure from Movement (SfM) techniques; ii) estimating the scanner position and poses. The proposed technology is illustrated for people screening, proving the capacity of the system to detect hidden weapons.