In this work, we introduce a novel chipless RFID tag with high encoding capacity, which uses sub-band frequency shift coding (SB-FSC) to increase the number of bits encoded by each resonator. The tag consists of an array of N variable-length microstrip line resonators, each with up to M = 9 notches (corresponding to digits 0-9) to encode N × log 2 M bits/tag. In addition, a pair of microstrip resonators serves as a frequency reference. A 60 × 80 mm 2 proof-of-concept tag is demonstrated with 13 + 2 resonant microstrip elements (for GTIN-13 code) to provide 43 bits/tag. The tag operates in the frequency range from 1.4 to 4.2 GHz with a coding density 36.7 bits/λ 2 /GHz at the center frequency. The presented design thus enables the integration of chipless RFID technology with the GS1 standard systems and Internet of Things (IoT) paradigm.
This In this paper we briefly describe QUBIC, the Q & U Bolometric Interferometer for Cosmology, a novel ground-based instrument designed to measure the extremely faint polarization anisotropy of the cosmic microwave background at intermediate angular scales. In particular we will describe simulations of the optical combiner and feedhorn array used to generate synthesized beam patterns for each detector on our focal plane. A QUBIC technical demonstrator has been built and is being installed in the observing site at Alto Chorrillos, Argentina with first light expected in 2022.
Space-time-coding digital metasurfaces are emerging as a powerful and versatile platform for advanced field manipulations in the joint space-frequency-polarization space and for overcoming some fundamental limitations in linear and time-invariant electromagnetic systems. Here, we provide a compact overview of results from recent and ongoing research in this field, ranging from harmonic beam-steering/shaping to non-reciprocal effects.
Remote sensing of marine plastic is a relatively new field and research into the capabilities of radar for detecting and monitoring marine plastic pollution is lacking, with several interactions and mechanisms being largely unknown. Here, we exploit the use of a C- and X-band radar to understand the capabilities of radar for detecting and monitoring marine plastics. Our results show that backscattering differences in C- and X-band between ‘clean’ water and test water filled with plastics can be detected in some conditions (based on statistical analysis). With C- and X- band detecting statistical differences in 20 / 67 and 48 / 68 cases respectively. We also find that the difference in backscattering is dependent on the size and shape of the plastic object, as well as the wave conditions in which the plastic is moving. This work provides key information on the capabilities of radar for detecting marine plastic litter and provides details which can be used for future planning in regard to tackling remote sensing of marine plastic pollution.
One of the most challenging shoulder injuries is rotator cuff tear that increases with aging and particularly happens among athletes. These tears cause pain and highly affect the functionality of the shoulder. The motivation of this work is detecting these tears by microwave tomographic imaging. This imaging method requires the solution of an inverse problem based on a minimization algorithm, with successive solutions of a direct problem. We make use of parallel computation from the domain decomposition method and domain-specific language with the open-source FreeFEM solver. Results demonstrate the possibility to detect tendon tear in a simplified shoulder model.
