789 research outputs found
Electromagnetic Transmit Array with Optical Control for Beamforming
This Proof-Of-Concept Paper Demonstrates the Feasibility of using a Slide Projector to Steer the Beam of a Transmit Array by Adding Solar Cells and Varactor Diodes to Each Unit Cell. by Irradiating Each Solar Cell with the Light of Different Intensities from a Slide Projector, the Measured Phase of the Wave Transmitted by the 4x4 Transmit Array Shifts within 92° at 4.26 GHz, While the Variation in Magnitude is Measured within 4 DB. Different Light Configurations Are Identified Via a Searching Algorithm to Achieve Peak/null Beamforming in a Particular Direction. the Beam of the Prototypical 4x4 Transmit Array Can Be Shifted by ±24° in Terms of the Peaks and -30° to 36° in Terms of the Nulls. the Concept of Adding Light Modulation to the Transmit Array with a Slide Projector Can Provide Update Rates of 10s of Milliseconds with Control of Brightness and Color Distributed over a Large Area of the Array
Reconfigurable Reflectarrays and Array Lenses for Dynamic Antenna Beam Control: A Review
Advances in reflectarrays and array lenses with electronic beam-forming
capabilities are enabling a host of new possibilities for these
high-performance, low-cost antenna architectures. This paper reviews enabling
technologies and topologies of reconfigurable reflectarray and array lens
designs, and surveys a range of experimental implementations and achievements
that have been made in this area in recent years. The paper describes the
fundamental design approaches employed in realizing reconfigurable designs, and
explores advanced capabilities of these nascent architectures, such as
multi-band operation, polarization manipulation, frequency agility, and
amplification. Finally, the paper concludes by discussing future challenges and
possibilities for these antennas.Comment: 16 pages, 12 figure
In-Band Co-Polarization Scattering Beam Scanning of Antenna Array Based on 1-Bit Reconfigurable Load Impedance
Controlling the in-band co-polarization scattering of the antenna while
maintaining its radiation performance is crucial for the low observable
platform. Thus, this paper studies the in-band co-polarization scattering beam
scanning of antenna arrays. Firstly, the regulation method of antenna
scattering is analyzed theoretically, concluding that the amplitude and phase
of the antenna's scattering field can be regulated by changing the load
impedance. Subsequently, PIN diodes are implemented to control the load
impedance of the antenna. Consequently, the scattering of the antenna, ensuring
that the antenna's scattering meets the condition of equal amplitude and a
phase difference of 180{\deg} when the PIN diode switches, thereby realizing
scattering beam scanning. Moreover, by introducing an additional pre-phase, the
inherent symmetric dual-beam issue observed in traditional 1-bit reconfigurable
structures is overcome, achieving single-beam scanning of the scattering.
Finally, a 1{\times}16 linear antenna array is designed and fabricated, which
operates at 6 GHz with radiation gain of 16.3 dBi. The scattering beams of the
designed array can point to arbitrary angles within 45{\deg}, significantly
reducing the in-band co-polarization backward radar cross section. The measured
results align well with the simulated ones
Advanced Radio Frequency Antennas for Modern Communication and Medical Systems
The main objective of this book is to present novel radio frequency (RF) antennas for 5G, IOT, and medical applications. The book is divided into four sections that present the main topics of radio frequency antennas. The rapid growth in development of cellular wireless communication systems over the last twenty years has resulted in most of world population owning smartphones, smart watches, I-pads, and other RF communication devices. Efficient compact wideband antennas are crucial in RF communication devices. This book presents information on planar antennas, cavity antennas, Vivaldi antennas, phased arrays, MIMO antennas, beamforming phased array reconfigurable Pabry-Perot cavity antennas, and time modulated linear array
Advanced space communications architecture study. Volume 2: Technical report
The technical feasibility and economic viability of satellite system architectures that are suitable for customer premise service (CPS) communications are investigated. System evaluation is performed at 30/20 GHz (Ka-band); however, the system architectures examined are equally applicable to 14/11 GHz (Ku-band). Emphasis is placed on systems that permit low-cost user terminals. Frequency division multiple access (FDMA) is used on the uplink, with typically 10,000 simultaneous accesses per satellite, each of 64 kbps. Bulk demodulators onboard the satellite, in combination with a baseband multiplexer, convert the many narrowband uplink signals into a small number of wideband data streams for downlink transmission. Single-hop network interconnectivity is accomplished via downlink scanning beams. Each satellite is estimated to weigh 5600 lb and consume 6850W of power; the corresponding payload totals are 1000 lb and 5000 W. Nonrecurring satellite cost is estimated at 113 million. In large quantities, the user terminal cost estimate is $25,000. For an assumed traffic profile, the required system revenue has been computed as a function of the internal rate of return (IRR) on invested capital. The equivalent user charge per-minute of 64-kbps channel service has also been determined
System integration and radiation pattern measurements of a phased array antenna employing an integrated photonic beamformer for radio astronomy applications
In this paper we describe the system integration and the experimental demonstration of a photonically beamformed four-element receiving array antenna for radio astronomy applications. To our knowledge, the work described here is the first demonstration of the squint-free, continuously tunable beamsteering capability offered by an integrated photonic beamformer based on optical ring resonator truetime-delay units, with measured radiation patterns. The integrated beamformer is realized in a low loss, complementary metal-oxide-semiconductor (CMOS) compatible optical waveguide technology. The measurements show a wideband, continuous beamsteering operation over a steering angle of 23.5 degrees and an instantaneous bandwidth of 500 MHz limited only by the measurement setup
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