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The sparse layouts of radio interferometers result in an incomplete sampling of the sky in Fourier space which leads to artifacts in the reconstructed images. Cleaning these systematic effects is essential for the scientific use of…
Ultrasonic backscatter measurements are widely used for microstructural characterisation. However, in materials containing strong anisotropy and spatial heterogeneity, the interpretation of backscatter signals becomes challenging because…
Antenna array calibration is necessary to maintain the high fidelity of beam patterns across a wide range of advanced antenna systems and to ensure channel reciprocity in time division duplexing schemes. Despite the continuous development…
We propose a new interferometer technique for high precision phase measurements such as those in gravitational wave detection. The technique utilizes a pair of optically coupled resonators that provides identical resonance conditions for…
This paper presents a non-zoned discrete dielectric lens comprising two or three matching layers to reduce the 50-110 GHz frequency range reflections. Based on Chebyshev and binomial multi-section transformers, the designed models use…
Evaluation of residual elastic strain within the bulk of engineering components or natural objects is a challenging task, since in general it requires mapping a six-component tensor quantity in three dimensions. A further challenge concerns…
In this research, the design and optimization of a novel leaf-shaped antenna inspired by natural leaf structures for radio frequency energy transfer is presented. The objectives of this study are to develop a bio-inspired antenna, optimize…
The operation of a wide field-of-view (WFOV) Cherenkov telescope is described. The detection of extensive air showers (EAS) of cosmic rays (CR) is based upon the coincidence with signals from the Yakutsk array. The data acquisition system…
The concepts of many optical devices are based on the fundamental physical phenomena such as resonances. One of the commonly used devices is an electromagnetic antenna that converts localized energy into freely propagating radiation and…
A method is proposed and experimentally explored for in-situ calibration of complex transmission data for superconducting microwave resonators. This cryogenic calibration method accounts for the instrumental transmission response between…
In this paper, reconfigurable high gain split ring resonator microstrip patch antenna is designed and analysed. The aim to design such type antenna is to achieve multiband application which is the demand of current technology in frequency…
Reconfigurable antennas (RAs) utilize the electromagnetic (EM) domain to provide dynamic control over antenna radiation patterns, which offers an effective way to enhance power efficiency in wireless links. Unlike conventional arrays with…
We propose a new approach for the accurate reconstruction of cosmic microwave background distributions from observations containing in addition to the primary fluctuations the radiation from unresolved extragalactic point sources and pixel…
In the present paper we investigate the transmission and reflection band behavior for a plane electromagnetic wave falling obliquely on an ideal layered structure. The dependence of this behavior on the problem parameters and wave incident…
In this work, we present a new, high performance algorithm for background rejection in imaging atmospheric Cherenkov telescopes. We build on the already popular machine-learning techniques used in gamma-ray astronomy by the application of…
Radio interferometry enables high-resolution imaging of astronomical radio sources by synthesizing a large effective aperture from an array of antennas and solving a deconvolution problem to reconstruct the image. Deep learning has emerged…
Hyperbolic metamaterials were initially proposed in optics to boost radiation efficiencies of quantum emitters. Adopting this concept for antenna design can allow approaching long-standing challenges in radio physics. For example, impedance…
In this letter, we present a fast and well-conditioned spectral method based on the Chebyshev polynomials for computing the continuous part of the nonlinear Fourier spectrum. The algorithm achieves a complexity of $O(N_{\text{iter.}}N\log…
We consider the problem of mapping with ultra-high angular resolution using a space-ground radio interferometer with a space antenna in a high orbit,whose apogee height exceeds the radius of the Earth by a factor of ten. In this case, a…
The Low Frequency Instrument on board the ESA Planck satellite is coupled to the Planck 1.5 meter off-axis dual reflector telescope by an array of 27 corrugated feed horns operating at 30, 44, 70, and 100 GHz. We briefly present here a…