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1. Experimental Results of a Compressive Reflector Antenna Producing Spatial Coding

   https://doi.org/10.1109/APUSNCURSINRSM.2018.8608304  

   Molaei, Ali; Graham, Katherine; Tirado, Luis; Ghanbarzadeh, Ashkan; Bisulco, Anthony; Heredia-Juesas, Juan; Liu, Chang; Von Holten, Joseph; Martinez-Lorenzo, Jose A. (July 2018, 2018 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting)

   This paper presents the design and fabrication of a Compressive Reflector Antenna (CRA) for high-sensing-capacity millimeter-wave imaging applications. The CRA is fabricated using additive manufacturing or 3D printing and metalized by applying silver conductive coating spray on its surface. The near-fields of the CRA are measured when it is fed by a conical horn antenna, a compressive horn antenna, and a perturbed cavity.The singular value distribution and sensing capacity of the CRA fed by the aforementioned antennas are calculated and compared. 

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2. Interferometric Sounding Using a Metamaterial-based Compressive Reflector Antenna

   https://doi.org/10.1109/TAP.2018.2809488  

   Molaei, Ali; Juesas, Juan Heredia; Blackwell, William; Lorenzo, Jose A. (January 2018, IEEE Transactions on Antennas and Propagation)

   This paper describes a new coded interferometric system for sensing the physical temperature radiated from the Earth’s surface. The proposed system consists of a Compressive Reflector Antenna (CRA) coated with Metamaterial Absorbers (MMA). The CRA and the MMA are used to code the received electromagnetic field in space and in frequency, at the focal plane array. The MMA is modeled by an equivalent magneto-dielectric medium having a definite thickness. A high frequency method based on Physical Optics is used to build the sensing matrix of the system, and the inverse problem is solved using a Nesterov-based Compressive Sensing methodology. Numerical examples are carried out in order to reconstruct the physical temperature of the Earth’s surface. The performance of the proposed system is compared to that of the conventional interferometric system GeoSTAR. Preliminary results show that the metamaterial-based CRA provides comparable performance to the GeoSTAR configuration with only half of the feeding elements, while keeping the same physical aperture size for the two configurations. 

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3. Field-based design of a resonant dielectric antenna for coherent spin-photon interfaces

   https://doi.org/10.1364/OE.419773  

   Li, Linsen; Choi, Hyeongrak; Heuck, Mikkel; Englund, Dirk (January 2021, Optics Express)

   We propose a field-based design for dielectric antennas to interface diamond color centers in dielectric membranes with a Gaussian propagating far field. This antenna design enables an efficient spin-photon interface with a Purcell factor exceeding 400 and a 93% mode overlap to a 0.4 numerical aperture far-field Gaussian mode. The antenna design with the back reflector is robust to fabrication imperfections, such as variations in the dimensions of the dielectric perturbations and the emitter dipole location. The field-based dielectric antenna design provides an efficient free-space interface for closely packed arrays of quantum memories for multiplexed quantum repeaters, arrayed quantum sensors, and modular quantum computers. 

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4. Cra: A Generic Compression Ratio Adapter for End-To-End Data-Driven Image Compressive Sensing Reconstruction Frameworks

   https://doi.org/10.1109/ICASSP40776.2020.9052998  

   Zhang, Zhikang; Xu, Kai; Ren, Fengbo (May 2020, IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP))

   End-to-end data-driven image compressive sensing reconstruction (EDCSR) frameworks achieve state-of-the-art reconstruction performance in terms of reconstruction speed and accuracy. However, due to their end-to-end nature, existing EDCSR frameworks can not adapt to a variable compression ratio (CR). For applications that desire a variable CR, existing EDCSR frameworks must be trained from scratch at each CR, which is computationally costly and time-consuming. This paper presents a generic compression ratio adapter (CRA) framework that addresses the variable compression ratio (CR) problem for existing EDCSR frameworks with no modification to given reconstruction models nor enormous rounds of training needed. CRA exploits an initial reconstruction network to generate an initial estimate of reconstruction results based on a small portion of the acquired measurements. Subsequently, CRA approximates full measurements for the main reconstruction network by complementing the sensed measurements with resensed initial estimate. Our experiments based on two public image datasets (CIFAR10 and Set5) show that CRA provides an average of 13.02 dB and 5.38 dB PSNR improvement across the CRs from 5 to 30 over a naive zero-padding approach and the AdaptiveNN approach(a prior work), respectively. CRA addresses the fixed-CR limitation of existing EDCSR frameworks and makes them suitable for resource-constrained compressive sensing applications. 

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5. Tunable broadband terahertz metamaterial absorber using V3O5

   https://doi.org/10.1063/5.0334797  

   Verbel, C; George, D M; Rodríguez-Solís, R A (July 2026, AIP Advances)

   The necessity for new materials capable of adapting to emerging technologies has become a significant challenge. This involves not only the synthesis of such materials but also their functional performance within the little-studied terahertz spectrum. In this paper, we propose a three-part unit cell metamaterial structure. The first layer consists of four L-shaped V3O5 resonators positioned at the corners, with two symmetric meander-line branches situated in the center. These elements serve to facilitate inductive or capacitive tuning, depending on the material state. The second is a SiO2 dielectric layer, and the third is an Au ground reflector. In the conductive state, the structure exhibited more than 90% absorption across two different frequency bands: from 1.60 to 3.02 THz and from 7.63 to 9.09 THz. By modulating the V3O5 conductivity, the proposed metamaterial design can function either as a reflector or an absorber. We analyze the influence of the thickness of the V3O5 and SiO2 layers, revealing their significant impact on the absorption spectra. The absorption phenomena are explored by analyzing the electric field distribution and applying impedance matching theory. In addition, the absorption spectra under different polarization angles show that the structure is insensitive to the direction of the electric field. This proposed absorber represents a new alternative for a wide range of promising applications in terahertz imaging, sensing, and detection. 

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