22,001 research outputs found
On-dimensional off-chip beam steering and shaping using optical phased arrays on silicon-on-insulator
Optical beam steering can find applications in several domains such as laser scanning, LiDAR (Light Detection And Ranging), wireless data transfer and optical switches and interconnects. As present beam steering approaches use mechanical motion such as moving mirrors or MEMS (Micro Electro Mechanical Systems) or molecular movement using liquid crystals, they are usually limited in speed and/or performance. Therefore we have studied the possibilities of the integrated silicon photonics platform in beam steering applications. In this paper, we have investigated a 16 element one-dimensional optical phased array on silicon-on-insulator with a field-of-view of 23. Using thermo-optic phase tuners, we have shown beam steering over the complete field-of-view. By programming the phase tuners as a lens, we have also shown the focusing capabilities of this one-dimensional optical phased array. The field-of-view can easily be increased by decreasing the width of the waveguides. This clearly shows the potential of silicon photonics in beam steering and scanning applications
A novel green antenna phase-shift system with data acquisition boards
A novel green phase shifter system is proposed in this research. The system is developed by a combination of reconfigurable beam steering antennas and data acquisition (DAQ) boards. A combination of two reconfigurable beam steering antennas, located side-by-side, forms a spatial configuration structure with a fabricated ‘green’ element plank of rice husk placed in between. The concept of a spatial configuration technique has been ‘mutated’ by shifting the structure of spiral feed line and aperture slots of first beam steering antenna by as much as 45 ◦ . The PIN diode switches connected to the DAQ boards enable the intelligent capability of the spatial antennas. The activation of certain degree radiation patterns of either the first beam steering antenna or the second beam steering antenna depends on the memory of the DAQ boards — Beam Manager. When an intruder comes from the cardinal angles of 0◦/ 360◦, 90◦, 180◦, or 270◦, its range and angles’ location will be automatically detected by the first antenna through the output ports of the 1st DAQ: P1.0, P1.1, P1.2, and P1.3. The second antenna is then activated by the output ports of the 2nd DAQ: P2.0 up to P2.3, to adaptively maneuver the beam towards four different ordinal directions of 45◦, 135◦, 225◦, and 315◦
Beam steering system
A simple technique for steering the beam of a multimodule phased array MST (mesosphere, stratosphere, troposphere) radar antenna is described. It is desirable to be able to point the antenna in multiple directions, so as to derive all components of the horizontal velocity. This was done on an experimental basis by adding parallel wire line to the feed and achieving a southward tilt of the antenna. It is proved possible to steer the beam through most of the available range without adversely affecting the VSWR seen from the transmitter. Calibrating the antenna direction can be accomplished by observing radio sources, though there are an inadequate number to cover all directions. For various assumed values of the aspect sensitivity in dB/deg, and the calculated antenna pattern, it is possible to calculate the effective pointing angle of the antenna, defined as that angle which would give an identical location for the centroid of the power spectrum if aspect sensitivity were absent. Using averaged apparent steering directions, eastward and northward winds were calculated for special radar runs simultaneous with 14 balloon launches at Peoria and results are presented
Demonstration of all-optical beam steering in modulated photonic lattices
We demonstrate experimentally all-optical beam steering in modulated photonic
lattices induced optically by three beam interference in a biased
photorefractive crystal. We identify and characterize the key physical
parameters governing the beam steering, and show that the spatial resolution
can be enhanced by the additional effect of nonlinear beam self-localization.Comment: 3 pages, 3 figure
The NOAA TOGA antenna array
The Aeronomy Laboratory recently installed a 100 x 100 meter array antenna with limited beam steering on Christmas Island as a part of the TOGA (Tropical Ocean and Global Atmosphere) program. The array and the associated beam steering and indicating hardware are described
Experimental Demonstration of >230{\deg} Phase Modulation in Gate-Tunable Graphene-Gold Reconfigurable Mid-Infrared Metasurfaces
Metasurfaces offer significant potential to control far-field light
propagation through the engineering of amplitude, polarization, and phase at an
interface. We report here phase modulation of an electronically reconfigurable
metasurface and demonstrate its utility for mid-infrared beam steering. Using a
gate-tunable graphene-gold resonator geometry, we demonstrate highly tunable
reflected phase at multiple wavelengths and show up to 237{\deg} phase
modulation range at an operating wavelength of 8.50 {\mu}m. We observe a smooth
monotonic modulation of phase with applied voltage from 0{\deg} to 206{\deg} at
a wavelength of 8.70 {\mu}m. Based on these experimental data, we demonstrate
with antenna array calculations an average beam steering efficiency of 50% for
reflected light for angles up to 30{\deg}, relative to an ideal metasurface,
confirming the suitability of this geometry for reconfigurable mid-infrared
beam steering devices
Two Dimensional Array Imaging with Beam Steered Data
This paper discusses different approaches used for millimeter wave imaging of
two-dimensional objects. Imaging of a two dimensional object requires reflected
wave data to be collected across two distinct dimensions. In this paper, we
propose a reconstruction method that uses narrowband waveforms along with two
dimensional beam steering. The beam is steered in azimuthal and elevation
direction, which forms the two distinct dimensions required for the
reconstruction. The Reconstruction technique uses inverse Fourier transform
along with amplitude and phase correction factors. In addition, this
reconstruction technique does not require interpolation of the data in either
wavenumber or spatial domain. Use of the two dimensional beam steering offers
better performance in the presence of noise compared with the existing methods,
such as switched array imaging system. Effects of RF impairments such as
quantization of the phase of beam steering weights and timing jitter which add
to phase noise, are analyzed
Design of controlled RF switch for beam steering antenna array
YesA printed dipole antenna integrated with a duplex RF switch used for mobile base
station antenna beam steering is presented. A coplanar waveguide to coplanar strip transition was adopted to feed the printed dipole. A novel RF switch circuit, used to control the RF signal fed to the dipole antenna and placed directly before the dipole, was proposed. Simulated and
measured data for the CWP-to-CPS balun as well as the measured performance of the RF switch are shown. It has demonstrated the switch capability to control the beam in the design of beam steering antenna array for mobile base station applications
Beam steering with dielectric metalattices
We study optical wave manipulations through high-index dielectric
metalattices in both diffractionless metasurface and diffractive metagrating
regimes. It is shown that the collective lattice couplings can be employed to
tune the excitation efficiencies of all electric and magnetic multipoles of
various orders supported by each particle within the metalattice. The
interferences of those adjusted multipoles lead to highly asymmetric angular
scattering patterns that are totally different from those of isolated
particles, which subsequently enables flexible beam manipulations, including
perfect reflection, perfect transmission and efficient large-angle beam
steering. The revealed functioning mechanism of manipulated interplays between
lattice couplings and multipolar interferences can shed a new light on both
photonic branches of metasurfaces and metagratings, which can potentially
inspire many advanced applications related to optical beam controls.Comment: 29 pages, 7 figures and comments welcome
Grid-Oscillator Beam-Steering Array
Recently Liao and York (see IEEE Trans. Microwave Theory Tech., vol.41, no.10, p.1810, 1993) showed that beam-steering can be achieved by detuning the end elements of a coupled-oscillator array. The advantage of this approach is that no phase shifters are required. Liao and York used a single line array of patch antennas. Here we report the results for a pair of 1×4 HEMT line-grid oscillators at 11 GHz. This array can scan from -6.5° to +5° by changing the bia
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