相关论文: Atmospheric Phase Correction Using Total Power Rad…

Atmospheric turbulence and aero-optic effects cause phase aberrations in propagating light waves, thereby reducing effectiveness in transmitting and receiving coherent light from an aircraft. Existing optical sensors can measure the…

This paper presents a non-classic approach to narrow field astrometry that offers a significant improvement over conventional techniques due to enhanced reduction of atmospheric image motion. The method is based on two key elements:…

This paper explores the use of reverberation chambers for TRP measurements of beamformed radiation by phased arrays at mmWave frequencies. First, the received power was verified by the one-sample K-S GoF test to follow the exponential…

A fully digital beam position and phase measurement (BPPM) system was designed for the linear accelerator (LINAC) in Accelerator Driven Sub-critical System (ADS) in China. Phase information is obtained from the summed signals from four…

Further analysis has been made on the millimeter and submillimeter-wave (100-1600 GHz or 3 mm - 188 micron) atmospheric opacity data taken with the Fourier Transform Spectrometer (FTS) at Pampa la Bola, 4800 m above sea level in northern…

Precision antenna calibration is required for mitigating the impact of foreground contamination in 21 cm cosmological radio surveys. One widely studied source of error is the effect of missing point sources in the calibration sky model;…

We report the first upper limits on the power spectrum of 21-cm fluctuations during the Epoch of Reionization and Cosmic Dawn from Phase II of the Hydrogen Epoch of Reionization Array (HERA) experiment. HERA Phase II constitutes several…

We develop a system for measurements of power spectra of transmitted light intensity fluctuations, in which the extraneous noise, including shot noise, is reduced. In essence, we just apply light, measure the power of the transmitted light…

We present 0.15" resolution observations of the 227 GHz continuum emission from the circumstellar disk around the FU-Orionis star PP 13S*. The data were obtained with the Combined Array for Research in Millimeter-wave Astronomy (CARMA)…

We consider an error model for phased array with gain errors and phase errors, with errors dependent on the phase applied and the antenna index. Under this model, we propose an algorithm for measuring the errors by selectively turning on…

Calibration of radio interferometric observations becomes increasingly difficult towards lower frequencies. Below ~300 MHz, spatially variant refractions and propagation delays of radio waves traveling through the ionosphere cause phase…

We have developed a modified Michelson interferometer type Raman laser system to manipulate cold 87 Rb atoms to interfere. A frequency modulated continuous wave technique was introduced to determine the optical path difference, thus…

Characterization of the millimeter wave wireless channel is needed to facilitate fully connected vehicular communication in the future. To study the multipath-rich, rapidly varying nature of the vehicular propagation environment, fast…

One major problem of phase-referencing VLBI observations are phase errors due to the unknown tropospheric zenith delay at each antenna. These errors degrade the quality of the phase-referenced image and limit the achievable astrometric…

This article investigates the noise performance of a two-element phased array and interferometer containing a recently introduced self-interference canceler, which in the context of this work acts as a mutual-coupling canceler. To this end,…

Ultra-high energy cosmic rays impinging onto the atmosphere induce huge cascades of secondary particles. The measurement of the energy radiated by these air showers in form of radio waves enables an accurate measurement of the cosmic-ray…

Interferometry can measure the shape or the material density of a system that could not be measured otherwise by recording the difference between the phase change of a signal and a reference phase. This difference is always between $-\pi$…

The 21 cm radiation of neutral hydrogen provides crucial information for studying the early universe and its evolution. To advance this research, countries have made significant investments in constructing large low-frequency radio…

Detecting cosmological signals from the Epoch of Reionization (EoR) requires high-precision calibration to isolate the cosmological signals from foreground emission. In radio interferometery, perturbed primary beams of antenna elements can…

Communication systems at millimeter-wave (mmW) and sub-terahertz frequencies are of increasing interest for future high-data rate networks. One critical challenge faced by phased array systems at these high frequencies is the efficiency of…