Practical method for the frequency domain reconstruction of stratified dielectric media

2000 ◽  
Author(s):  
Valeri A. Mikhnev ◽  
Pertti Vainikainen
Keyword(s):  
Frequency Domain ◽  
Practical Method ◽  
Dielectric Media ◽  
Frequency Domain Reconstruction

FREQUENCY DOMAIN RECONSTRUCTION FOR PHOTO- AND THERMOACOUSTIC TOMOGRAPHY WITH LINE DETECTORS

2009 ◽  
Vol 19 (02) ◽  
pp. 283-306 ◽  
Author(s):  
MARKUS HALTMEIER
Keyword(s):  
Wave Equation ◽  
Frequency Domain ◽  
Boundary Data ◽  
Three Dimensional ◽  
Photoacoustic Tomography ◽  
Two Dimensional ◽  
Reconstruction Problem ◽  
Acoustic Data ◽  
Dimensional Wave ◽  
Frequency Domain Reconstruction

This paper is concerned with a version of photoacoustic tomography, that uses line shaped detectors (instead of point-like ones) for the recording of acoustic data. The three-dimensional image reconstruction problem is reduced to a series of two-dimensional ones. First, the initial data of the two-dimensional wave equation is recovered from boundary data, and second, the classical two-dimensional Radon transform is inverted. We discuss uniqueness and stability of reconstruction, and compare frequency domain reconstruction formulas for various geometries.

scholarly journals Reception of OAM Radio Waves Using Pseudo-Doppler Interpolation Techniques: A Frequency-Domain Approach

2019 ◽  
Vol 9 (6) ◽  
pp. 1082 ◽  
Author(s):  
Marek Klemes
Keyword(s):  
Frequency Domain ◽  
Doppler Frequency ◽  
Practical Method ◽  
Far Field ◽  
Radio Waves ◽  
Antenna Structure ◽  
Transmitting Antenna ◽  
Doppler Frequency Shifts ◽  
Weighting Coefficients ◽  
Frequency Domain Approach

This paper presents a practical method of receiving waves having orbital angular momentum (OAM) in the far field of an antenna transmitting multiple OAM modes, each carrying a separate data stream at the same radio frequency (RF). The OAM modes are made to overlap by design of the transmitting antenna structure. They are simultaneously received at a known far-field distance using a minimum of two antennas separated by a short distance tangential to the OAM conical beams’ maxima and endowed with different pseudo-Doppler frequency shifts by a modulating arrangement that dynamically interpolates their phases between the two receiving antennas. Subsequently down-converted harmonics of the pseudo-Doppler shifted spectra are linearly combined by sets of weighting coefficients which effectively separate each OAM mode in the frequency domain, resulting in a higher signal-to-noise ratios (SNR) than possible using spatial-domain OAM reception techniques. Moreover, no more than two receiving antennas are necessary to separate any number of OAM modes in principle, unlike conventional MIMO (Multi-Input, Multi-Output) which requires at least K antennas to resolve K spatial modes.

On the use of frequency-domain reconstruction algorithms for photoacoustic imaging

2011 ◽  
Vol 16 (8) ◽  
pp. 086002 ◽  
Author(s):  
Rainer Schulze ◽  
Gerhard Zangerl ◽  
Markus Holotta ◽  
Dirk Meyer ◽  
Florian Handle ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Photoacoustic Imaging ◽  
Reconstruction Algorithms ◽  
Frequency Domain Reconstruction
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