A reconfigurable antenna (RA) capable of steering its beam into the hemisphere corresponding to <inline-formula> <tex-math notation="LaTeX">\theta \in </tex-math></inline-formula> {−40°, 0°, 40°}, ...<inline-formula> <tex-math notation="LaTeX">\phi \in </tex-math></inline-formula> {0°, 45°, 90°, −45°}, and of changing 3 dB beamwidth, where <inline-formula> <tex-math notation="LaTeX">\theta _{3\,\text {dB}} \in </tex-math></inline-formula>(40°, 100°), <inline-formula> <tex-math notation="LaTeX">\phi \in </tex-math></inline-formula> {45°, 90°, −45°} for broadside direction is presented. The RA operating in 5 GHz band consists of a driven patch antenna with a parasitic layer placed above it. The upper surface of the parasitic layer has two pixelated metallic strips, where each strip has four pixels. The pixels connected via p-i-n diode switches enable to change the current distribution on the antenna providing the desired modes of operation. A prototype RA was characterized indicating an average gain of 8 dB. Measured and simulated impedance and radiation patterns agreed well. The proposed RA offers an efficient solution by using less number of switches compared to other RAs. The system level simulations for a 5G orthogonal frequency division multiple access system show that the RA improves capacity/coverage tradeoff significantly, where the RA modes and users are jointly determined to create proper beamwidth and directivity at the access point antennas. For a hotspot scenario, the presented RA provided 29% coverage and 16% capacity gain concurrently.
Space-shift-keying (SSK) and spatial modulation (SM) enable multiple antenna transmission systems to convey information on antenna indices. While SSK/SM helps reduce the number of radio frequency ...(RF) chains, large numbers of antennas and low spatial correlations are required to achieve high data rates. This work investigates the use and design of multifunctional reconfigurable antennas (MRAs) for SSK/SM based transmission where a single-element MRA generates large numbers of modes. To enhance legacy SSK/SM performance while reducing RF hardware complexity, we propose single- and multi-carrier antenna mode-shift keying (MoSK) and mode modulation (MoM) schemes facilitated by MRAs. Based on an error probability analysis, we determine criteria for MRA design and mode set selection suitable for MoSK/MoM. We also develop two MRA designs and investigate their performances over Rayleigh fading channels. We argue that by creating MRA modes with low pattern correlations, channel correlations can be reduced to improve the detection performance. Extensive simulations demonstrate that MoSK/MoM performance exceeds that of SSK/SM along with significant complexity reduction. For instance, a single-carrier MoSK/MoM using a single MRA with 8 modes achieves about 2 dB gain compared to legacy SSK/SM requiring 8 antennas, and by multi-carrier MoSK/MoM using 4 subcarriers, an MRA with 32 modes can attain an error rate performance comparable to this single-carrier system.
In this letter, a reconfigurable dual-polarized broadband antenna with beam-steering capabilities using a parasitic layer is proposed for 5G new radio (NR) frequency range 1 (FR-1) applications. The ...antenna is a dual-port aperture-stacked patch structure with symmetrical orthogonal (horizontal and vertical) currents. The beam-steering is achieved by a pair of reconfigurable cross-shaped parasitic strips, which bestow the antenna three main beam directions <inline-formula><tex-math notation="LaTeX">\theta =\lbrace {\sim} {-}25^{\circ },0^{\circ }, {\sim} 25^{\circ }\rbrace, \phi =\lbrace 0^{\circ }\rbrace</tex-math></inline-formula> with pointing and gain (<inline-formula><tex-math notation="LaTeX"> 7</tex-math></inline-formula> dB) stability across a <inline-formula><tex-math notation="LaTeX">30 \%</tex-math></inline-formula> impedance bandwidth (<inline-formula><tex-math notation="LaTeX">S_{11}, S_{22} < -10</tex-math></inline-formula> dB) from <inline-formula><tex-math notation="LaTeX">3.2 - 4.3</tex-math></inline-formula> GHz for both ports/polarizations. A prototype of the antenna is manufactured and measured demonstrating results in accordance with simulation expectations.
This letter presents the error vector magnitude (EVM), intermodulation (IM), and radiation performances of a reconfigurable antenna capable of varying its bandwidth between 3.4-3.6 and 3.1-3.9 GHz ...bands, and steering its main beam into three directions pertaining to <inline-formula><tex-math notation="LaTeX">\theta \in \lbrace -30^{\circ },0^{\circ },30^{\circ }\rbrace</tex-math></inline-formula> and <inline-formula><tex-math notation="LaTeX">\phi \in \lbrace 0^{\circ }\rbrace</tex-math></inline-formula> for each band. Two parasitically coupled reconfigurable layers located on top of a driven antenna used in conjunction with a reconfigurable feed layer employing p-i-n diode switches enable a concurrent configuration of an impedance bandwidth and a radiation pattern. The maximum realized gain of <inline-formula><tex-math notation="LaTeX">\sim</tex-math></inline-formula>9 dB has been achieved for all modes of operation as shown by measurements and simulations. Measurements indicated less than <inline-formula><tex-math notation="LaTeX">-</tex-math></inline-formula>25 dB (<inline-formula><tex-math notation="LaTeX">5.6\%</tex-math></inline-formula>) EVM for input powers up to 30 dBm and revealed that the combined effects of loose solder joints and large nonlinear response of p-i-n diodes are the main factors resulting in passive IM products.
The ability to utilize resources to meet the need of growing diversity in services and user behavior marks the future of cognitive wireless communication systems. Cognitive wireless technologies for ...vehicular communications, in combination with Orbital Angular Momentum (OAM) modes aim at extending direct Non-Line-Of-Sight (NLOS) short-distance communications for smart mobility. In this regard, OAM antennas need to be developed to support these technologies. To this end, here we de-scribe a compact antenna supporting the first OAM modes. Also, the antenna properties are discussed and are numerically and experimentally validated for OAM modes of l=\pm 1 . Particularly, for the considered OAM modes, the antenna achieves more than 500 MHz operation bandwidth at the frequency of operation of 3.5 GHz. Also, for l=\pm 1 OAM modes, the null beamwidth aligns precisely with the anticipated dimensions theoretically computed.
A broadband and high gain antenna, which operates at (3.2-4.2) GHz band and achieves maximum ~12.3 dB realized gain, has been presented. The antenna architecture consists of a driven aperture coupled ...stacked patch antenna on top of which parasitic radiators are placed. A prototype antenna has been fabricated and characterized. The main advantage of the presented antenna is its high gain which is maintained over a wide bandwidth. This property is very important to improve the signal to noise ratio (SNR) of point to point communication systems.
Radiation Pattern Reconfigurable Horn Antenna Tanagardi, Mehmet; Towfiq, Md Asaduzzaman; Cetiner, Bedri A.
2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting,
2019-July
Conference Proceeding
A radiation pattern reconfigurable horn antenna (RHA) capable of steering its main beam in three directions in the semi-sphere space corresponding to θ ∈ {-25°, 0°, 25°}, is presented. The RHA ...consists of a driven X-band (10 GHz-11.5 GHz) horn antenna, a reconfigurable parasitic layer and a dielectric loaded truncated pyramid (DLTP). The surface of the parasitic layer has two metallic strips and a grid of 4x4 square metallic pixels, which are interconnected by PIN diode switches, thereby enable configuring the surface geometry. The simulated results indicate that from 10 GHz to 11.5 GHz realized gain of ~ 14 dB is achieved in all modes of operation.
This paper presents a new class of multifunctional reconfigurable antenna (MRA) technology that provides continuous beam steering capability at individual antenna level with low power consumption. A ...prototype MRA operating in the 28 GHz band that uses varactor diodes as interconnecting switches between its parasitic elements was designed by full-wave electromagnetic (EM) simulations. Simulated results demonstrate the continuous beam steering capability of the designed MRA. This new MRA technology has a simple architecture and consumes low power, thus it holds the potential to satisfy the antenna array performance requirements of fifth generation (5G) and beyond wireless systems with low cost and low power.
This work presents a novel design approach on optimizing the complex feeding coefficients of an antenna array to achieve a desired beam pattern. The approach uses a convolutional neural network which ...takes an image representation of a desired radiation pattern and generates the corresponding phase gradient over the array aperture. To demonstrate the performance of the approach, an 8×8 planar array has been used. The results show the potential for machine learning to optimize antenna parameters in more complicated antenna systems, where an efficient way of developing antenna pattern codebooks by using a trained neural network is used.
The complexity of voltage collapse problem has increased with increasing interconnections between independent power systems. When a bulk power transmission network (generation and transmission ...system) is operated close to the voltage stability limit, it becomes difficult to control the reactive power demand for that system. As a result, the system voltage stability is affected, which if undetected may lead to voltage collapse. Voltage collapse is generally caused by either of the two types of system disturbances: load variations and contingencies. In respect to voltage collapse phenomenon, information based on loading capability is highly important for the secure operation of the power system. In this paper, the most probable voltage collapse points of the Bangladesh Power System Network (BPSN) have been predicted using continuation power flow method. Voltage stability of BPSN is improved by placing static VAR compensator (SVC). A load flow analysis based technique is used to determine the amount of reactive power support needed. Results show good improvements.
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