Orthogonal Beams Research Articles

Comparison of Orthogonal Kilovolt X-Ray Plain Film and Cone Beam CT Matching Results in Setup Error Assessment and Correction for EB-PBI During Free Breathing

Comparison of Orthogonal Kilovolt X-Ray Plain Film and Cone Beam CT Matching Results in Setup Error Assessment and Correction for EB-PBI During Free Breathing

Single Field Spot-Scanning (SFSS) Is Dosimetrically Superior to 2-Field Intensity Modulated Proton Therapy (IMPT) for Proton Postmastectomy Radiation Therapy (PMRT)

Single Field Spot-Scanning (SFSS) Is Dosimetrically Superior to 2-Field Intensity Modulated Proton Therapy (IMPT) for Proton Postmastectomy Radiation Therapy (PMRT)

Design of fused-silica transmission gratings for orthogonal polarizing beam combiners

Deep-etched rectangular fused-silica transmission gratings used as orthogonal polarizing beam combiners at the wavelength of 532nm are designed based on the modal method. The fabrication tolerances and the properties of the orthogonal polarizing beam combiners are analyzed by rigorous coupled-wave analysis. It is shown that these gratings have large fabrication tolerances and good properties when the diffraction efficiencies are greater than 90%. The optimal grating is highly efficient (>95%) over broad incidence condition and also has large fabrication tolerances.

Experimental observation and analysis of all-fiber plasmonic double Airy beams.

The propagation dynamics of all-fiber plasmonic double parallel and orthogonal Airy beams are experimentally demonstrated. Two slits and groove arrays were fabricated by focused ion beam (FIB) milling on the gold coated end facet of an optical fiber to generate two Airy beams simultaneously. Sub-wavelength self-focusing of double parallel Airy beams in free space is experimentally verified. Effects of geometrical parameters on the intensity profiles of the focal spot are analyzed in detail. The characteristics at the junction of the two main lobes can be adjusted by controlling the initial phase difference of the two Airy beams. The propagation of two orthogonal Airy beams is also experimentally investigated. Multi-Airy beams are of importance to realize all-fiber optical trapping, fiber integrated devices, and laser shaping.

Fiber-coupled polarization independent liquid crystal Fabry–Perot tunable filter

A polarization independent Fabry–Perot liquid crystal tunable filter coupled to an optical fiber is demonstrated using polarization diversity. Using a Wollaston prism, the beam splits into two orthogonal beams, while the polarization of one of the beams is rotated by 90 deg using a variable half wave plate. The two beams are then combined into an optical fiber. Tuning of unpolarized light over the range 720 to 800 nm is demonstrated.

On the Forming of Orthogonal Beams by Planar Array Antennas

A general approach to determination of geometrical parameters of planar array antennas designed for forming of orthogonal beams steered in the nodes of a Cartesian periodic lattice specified in the space of direction cosines is proposed. The proof of orthogonality of the complex amplitude distributions and appropriate array factors for the arrays constructed according to the proposed approach is given. The role of the array element patterns in providing the beam pattern orthogonality is underlined. The issue of the number of the array elements necessary for forming of the specified number of beams is discussed. A few demonstrative examples of the beam clusters and appropriate configurations of the arrays where the number of the elements is equal to the specified number of the beams are considered.

FPGA Implementation of Mimo E-SDM for future communications wireless networks

Multiple-input multiple-output (MIMO) systems applying the Eigenbeam-Space Division Multiplexing (E-SDM) technique can be considered as optimal MIMO systems because of providing the highest channel capacity and good communications reliability. In the systems, orthogonal transmission beams are formed between transmit and receive sides; and also optimal transmit input data are adaptively allocated. In addition, a simple detection can be used at receiver to totally eliminate sub-stream interference. Therefore, MIMO E-SDM systems have been considered as a good potential technology for future high speed data transmission networks. Although there have been a lot of technical papers evaluated the systems based on theory analyses and/or computer-based simulation, just few ones have been considered the MIMO E-SDM systems based on hardware design. The main contribution of this paper is to present our own design and implementation of 2x2 and 2x3 MIMO E-SDM systems on FPGA Altera Stratix DSP Development KIT using Verilog HDL, an important step before going to make integrated circuits. The bit-error rate performance the consumption for our design of these systems have shown that our design is successful.

Quantitative Photoswitching in Bis(dithiazole)ethene Enables Modulation of Light for Encoding Optical Signals

AbstractUsing one ray of light to encode another ray of light is highly desirable because information in optical format can be directly transferred from one beam to another without converting back to the electronic format. One key medium to accomplish such an amazing task is photoswitchable molecules. Using bis(dithiazole)ethene that can be photoswitched between its ring‐open and ring‐closed states quantitatively with excellent fatigue resistance and high thermal stability, it is shown that quantitative photoreversibility allowed the photoswitching light to control other light travelling through the photoswitchable medium, a phenomenon of transferring information encoded in one light ray to others, thus imparting photo‐optical modulation on the orthogonal light beam.

Quantitative Photoswitching in Bis(dithiazole)ethene Enables Modulation of Light for Encoding Optical Signals

Using one ray of light to encode another ray of light is highly desirable because information in optical format can be directly transferred from one beam to another without converting back to the electronic format. One key medium to accomplish such an amazing task is photoswitchable molecules. Using bis(dithiazole)ethene that can be photoswitched between its ring-open and ring-closed states quantitatively with excellent fatigue resistance and high thermal stability, it is shown that quantitative photoreversibility allowed the photoswitching light to control other light travelling through the photoswitchable medium, a phenomenon of transferring information encoded in one light ray to others, thus imparting photo-optical modulation on the orthogonal light beam.

Orthogonal and fine lithographic structures attained from the next generation proton beam writing facility

A second generation proton beam writing (PBW) system has been built at the Centre for Ion Beam Applications at the National University of Singapore for fabrication of high aspect ratio 3D nano lithographic structures. System improvements and a few lithographic structures obtained with this facility are presented in this paper. Through accurate alignment of the magnetic quadrupole lenses and the electrostatic scanning system, orthogonal beam scanning has been achieved. The earlier constrain of limited beam scan area has been overcome by adopting a combination of beam and stage scanning as well as stitching. With these improvements smallest ever Ni structure of 65 nm in width has been fabricated using nickel electroplating on a proton beam written PMMA sample in the second generation PBW facility. Using this improved PBW facility, we have also demonstrated the fabrication of fine lithographic patterns with 19 nm line width and 60 nm spacing in 100 nm thick negative high resolution hydrogen silsesquioxane resist. Future possible system improvements leading to finer resolution will be discussed briefly.

DESIGN AND IMPLEMENTATION OF A 3 X 3 ORTHOGONAL BEAM-FORMING NETWORK FOR PATTERN-DIVERSITY APPLICATIONS

An orthogonal beam-forming network (BFN) is proposed for 4G pattern-diversity applications. Different from the traditional Butler beam-forming networks with 2 N orthogonal beams, the orthogonal BFN, composed of three 180 ◦ hybrids and a 90 ◦ phase shifter, provides three orthogonal beams. Design procedure of the orthogonal BFN based on the factorization of its transmission matrix is derived. Moreover, in order to implement the proposed orthogonal BFN with low insertion loss, a rat- race has been used to realize unequal power distribution between its two output ports. The measured scattering parameters of the orthogonal BFN are compared with the analytical and the simulated scattering parameters, validating the expected behavior. In addition, by varying the output power ratio of the non-equi-amplitude 180 ◦ hybrid, the performance of the orthogonal BFN is improved when the proposed orthogonal BFN is used in an antenna array.

强非局域正交偏振双厄米高斯光束的传输特性

强非局域正交偏振双厄米高斯光束的传输特性

Elevation finding algorithm in beam domain under multi‐path environments for VHF radar

A novel elevation finding algorithm in the beam domain is proposed for very high frequency (VHF) radar under multi-path environments. Three orthogonal beams (upper, middle and lower beams) are formed using fast Fourier transform. The orthogonal vector of the covariance matrix in beam domain is analytically derived to form the angle spectrum, the peak of which corresponds to the estimation of the elevation of the target. In addition, the complex reflection coefficient (CRC) is also available when the elevation is estimated. The validity and veracity of the proposed scheme is verified with simulations. The relationships between the estimation performance, the signal-to-noise-ratio, elevation and CRC are also investigated, respectively. Furthermore, field data sets are used for validation. It is found that when the elevation is <;1/5 of the beamwidth, which poses great difficulty for elevation estimation. The estimation precision is still <;1/35 of the beamwidth. The proposed algorithm is particularly suitable for VHF band radars and ship-borne radars, where the multi-path effect is serious.

Free Vibrations of Beam System Structures with Elastic Boundary Conditions and an Internal Elastic Hinge

The study of the dynamic properties of beam structures is extremely important for proper structural design. This present paper deals with the free in-plane vibrations of a system of two orthogonal beam members with an internal elastic hinge. The system is clamped at one end and is elastically connected at the other. Vibrations are analyzed for different boundary conditions at the elastically connected end, including classical conditions such as clamped, simply supported, and free. The beam system is assumed to behave according to the Bernoulli-Euler theory. The governing equations of motion of the structural system in free bending vibration are derived using Hamilton's principle. The exact expression for natural frequencies is obtained using the calculus of variations technique and the method of separation of variables. In the frequency analysis, special attention is paid to the influence of the flexibility and location of the elastic hinge. Results are very similar with those obtained using the finite element method, with values of particular cases of the model available in the literature, and with measurements in an experimental device.

Performance of Dualbeam MIMO for Millimeter Wave Indoor Communication Systems

Millimeter wave (MMW) communication provides high data rates for the personal area networks with the availability of 57---64 GHz unlicensed spectrum, in indoor environment. Multipath fading being pre-dominant in indoor, multi input multi output (MIMO) technology is considered to be the ideal choice compared with the existing systems. As spatial diversity in both transmit and receive enhances the diversity gain, the performance of the system is further enhanced by introducing transmit beamforming based antenna beam diversity. In classical $$2\times 2$$ 2 × 2 MIMO, a diversity gain of 4 is achieved, whereas in this work, space time block code matrix of code rate 1/2 and dualbeam $$2\times 2$$ 2 × 2 MIMO with diversity gain 8 is considered. Dualbeam is generated by antenna array with four elements per array with out of phase feed configuration. The weight vector of the beamforming network is out of phase as to reduce the interference between the beams. The dualbeam transmitter is designed with unknown channel state information. Training symbols are transmitted to train and track the channel statistics at the receiver. The proposed work is carried out for MMW indoor system. The indoor channel is modeled using Triple Saleh–Valenzuela (TSV) model that takes into account both time of arrival and the angle of arrival information of the rays. Channel estimation is done for classical MIMO and the above proposed model in both Rayleigh and TSV channel. The orthogonal beams facilitate linear processing in the receiver. Hence maximum ratio combiner with maximum likelihood decoder is used in the receiver to decode the transmitted data. Classical MIMO and dualbeam MIMO are evaluated with respect to bit error rate and channel models. An improved diversity order is achieved with dualbeam MIMO compared to classical MIMO, with a power gain of 1.6 dB. The dualbeam MIMO using TSV is found to perform better compared to dualbeam MIMO using Rayleigh in the low Energy per bit to Noise level $$(\hbox {E}_{\mathrm{b}}/\hbox {N}_{0})$$ ( E b / N 0 ) with a power gain of 2 dB.

The estimation of the degree of coherence of mutually orthogonal beams: New approaches

A theoretical model for calculating the motion dynamics of the particles of different light-scattering mechanisms in the energy inhomogeneous optical field is suggested. The direct relationship between the motion velocity of the tested particles in the created field and the degree of coherence of mutually orthogonal linearly polarized plane waves is demonstrated.

Design and Implementation of a Quasi-Orthogonal Switching Beam-Former for Triangular Arrays of Three Radiating Elements

An innovative switching multi-beam network for triangular arrays of three radiating elements is proposed. This novel network provides three orthogonal beams in a desired elevation angle and a fourth one in the broadside steering direction. The network is composed of four-port 3-dB quadrature hybrid power couplers and fixed phase shifters. In this paper, a relation between network components, radiating element distance and beam steering directions is shown. Application of the proposed dissipative network to the triangular cell of three double stacked patches of 1.7 GHz and 60 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> beamwidth that integrates the intelligent antenna GEODA with an array distance of 0.56 λ is exhibited. Measured scattering parameters of the network are compared with both, theoretical and simulated scattering matrices, validating the expected behavior. Besides, by combining two complementary single proposed networks, a matrix that supplies six orthogonal beams in a given elevation angle and a seventh one in the broadside steering direction has been built. Moreover, the whole system, dissipative network with GEODA cell array, has been measured in the anechoic chamber of the Radiation Group at Technical University of Madrid, demonstrating a successful performance.

Analysis of Influence of Slab’s Reinforcement on Seismic Bearing Capacity of Beam’s Cross-Section in Cast-&lt;i&gt;In Situ&lt;/i&gt; Frame Structure

“strong beam and weak column”is the main failure states of reinforced concrete frame structure in the earthquake．This paper studies the influence on the virtual cross-section bearing capacity on extremity of frame beam in reinforced concrete in experiment through the project example and analysis of finite element method,such as slab’s reinforcement，the rigidity of frame beam, the rigidity of orthogonal beam and so on．Exploring the mechanism of slab and frame work together to determine the width of effective flange，which provides references for structural design and engineering application．

Experimental Study on the Influence of Slab’s Reinforcement on Seismic Bearing Capacity of Beam’s Cross-Section in Cast-&lt;i&gt;In Situ&lt;/i&gt; Frame Structure

“strong beam and weak column”is the main failure states of reinforced concrete frame structure in the earthquake．This paper is the experimental study of the influence on the virtual cross-section bearing capacity on extremity of frame beam in reinforced concrete，which is affected by some element，such as slab reinforcement，the rigidity of orthogonal beam and so on．Exploring the mechanism of slab and frame work together to determine the width of effective flange，which provides references for structural design and engineering application．

The Use of New Approaches to Estimating the Coherence Properties of Mutually Orthogonal Beams

theoretical model for calculating the motion dynamics of the particles of different light-scattering mecha- nisms in the energy inhomogeneous optical field is suggested. The direct relationship between the motion velocity of the tested particles in the created field and the degree of coherence of mutually orthogonal linearly polarized plane waves is demonstrated. The possibilities of using the normalized value of the averaged velocity for particles of the !100 sizes to define the degree of coherence of mutually orthogonal linearly polarized fields are shown.