The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
A high gain 5.8 GHz multiple input multiple output (MIMO) 2×2 Array antenna with dimension of 58 × 110 mm2 is proposed in this paper. The proposed design is composed of two sets of four elements antenna array. Each element is constructed from four truncated arrays radiating elements which capable to achieve circular polarized capability. The antenna is fed by two coaxial feeds with full ground plane...
We derive capacity upper and lower bounds for a multi-user multiple-input multiple-output (MU-MIMO) system in a two dimensional line-of-sight environment where the central node is equipped with a uniform circular array and the remote nodes are distributed from the central node at an equal distance and equal angular separation. We first show that this channel can be represented by a circulant matrix...
In light of the emerging fifth generation (5G) mobile communications, large-scale antenna systems (LSAS, also known as large-scale MIMO, massive MIMO, etc.) present a highly promising solution to meet the demanding requirements of even higher network capacity, throughput, spectrum- and energy-efficiency than 4G systems. Channel measurements show that unlike conventional MIMO, quite a few new channel...
In this paper, the asymptotic favorable propagation (FP) condition is thoroughly analyzed under the assumption that user terminals (UTs) are gathered in a size-limited circular area. Uniform distribution is assumed for UTs. Assumptions that are accordant with realistic propagation environment are used, which mathematically bring in close-form approximations for mean and variance of FP. Based on these...
Compact structure of the large-scale antenna array and low power angular spread (PAS) in vertical dimension improve the fading correlation of wireless channel dramatically in full-dimension multiple input multiple output (FD-MIMO) systems. Whereby beamforming (BF) can fully exploit the quasi-static spatial correlation to reduce dependence on the instantaneous channel state information at the transmitter...
In a short-range multiple-input and multiple-output (SR-MIMO) transmission system that relies on line-of-sight (LOS) propagation, the channel matrix is determined by the antenna geometry, hence radio frequency (RF) signal processing by using an analog matrix circuit is a valid means of separating spatially-multiplexed multiple signal streams. To date several simple decoding methods utilizing this...
The performance of wireless communication systems in difficult radio conditions needs to be enhanced. More and more systems use indeed advanced antenna techniques to do so. Especially one type of advanced antenna technique, beamforming, is found more and more often and presented as the promising overall answer to increase performance. The theory of beamforming is quite well known since a while, but...
MIMO radar and Khatri-Rao (KR) product virtual array are the methods for increasing angular resolution of the array radar. The KR product is not suited to radar because KR product needs data property of uncorrelated wave incidence. However, when we extract responses of moving targets having different Doppler frequencies by Doppler filtering, the KR product array works almost properly because their...
This paper presents an automatic impedance-matching algorithm that can sequentially realize a simultaneous conjugate-matching state for all the elements in an N-element array antenna. The analytical results show that the converged solution obtained from the proposed algorithm agrees well with the solution calculated by the analytical deterministic equation, confirming the validity of the proposed...
In INDIA, fourth generation mobile networks were already deployed in defined locations. In many developed countries, 4G is playing a prominent role. Even though 4G networks generates excellent data rates (more than 500mbps), there are few challenges still to be addressed. The major problems include optimum allocation of spectrum and huge consumption of energy. The emerging wireless applications were...
This paper proposes a novel reflectarray which can reflect two frequency radio waves within the same polarization. To achieve this, this paper adopts combination of mushroom-like structure and dipole array. The analysis results using HFSS shows that proposed reflectarray structure can be designed using gap size between mushroom patches to determine reflection phase at higher frequency and dipole length...
A dual polarization of patch antenna array for IEEE 802.11b/g/n MIMO applications are proposed and experimentally studied in this paper. The four by one patch antenna array printed on 300mm by 100mm by 0.8 mm FR4 substrate. The FR4 substrate is 2.5 mm above the metal ground plane. The patch array has two input ports for the orthogonal polarizations MIMO application. The measured efficiency and gain...
This paper proposes an analog-digital hybrid eigenmode transmission technique for massive short-range MIMO, which utilizes both analog and digital beamformings. In this method, first, a channel matrix in a plane-symmetrically configured MIMO array is block-diagonalized by analog beamforming with hybrid couplers. Then, eigenmode transmission is virtually realized by digital beamforming toward each...
In massive MIMO transmission, implicit beam forming was studied to eliminate channel state information (CSI) feedback. However, it is essential to introduce the calibration circuit which compensates the difference of complex amplitudes between the transmitters and receivers. This paper presents the effectiveness of calibration circuit for massive MIMO transmission by the testbed which implements the...
This paper investigates the mutual interactions between MIMO antenna radiation and multipath characteristics to obtain useful knowledge that can be employed in the design of a three-dimensional OTA system. In investigating factors that may affect the MIMO channel capacity, we focus on two key parameters, the incident wave power distribution in the elevation direction and the radiation pattern of terminal...
Large scale MIMO is a new field for wireless communication. Theoretical analysis was usually done with independent distributed complex Gaussian channels and unlimited antennas. In this work, we exhibit the performance of linear precoding under the three dimension (3D) channel model calibrated by 3GPP in the 3D-UMÌ scenario. Considering the multi-cell multiuser MIMO (MU-MIMO), we assume that the base...
For massive MIMO systems, it is very challenging to have the large-scale antennas for a compact base station. This paper presents a 36 sub-sectors for a compact millimeter-wave base station. The antenna array for each sub-sector is comprised of 16 planar high-gain dielectric-loaded antipodal linearly tapered slot antenna (ALTSA) elements arranged in a 4×4 configuration. Down to 36 feed ports are required...
An iterative learning control (ILC) approach is developed for electrode array based functional electrical stim-ulation. Building on the ‘phase-lead ILC’ form that has proved clinically effective with single electrodes, the first principled extension to multivariable systems is undertaken, resulting in a set of update laws which require minimal plant information that can be identified in a short initial...
A compressed footprint high gain beam steering parasitic antenna array is introduced for 5 GHz WLAN application in portable wireless devices. The collinear dipole array (consisting of a number of driven and parasitic dipoles) beam can be steered in 0, 60, and −60 degrees in the azimuth plane with the help RF switches. The peak gain of the array ranges from 11.7 to 12.2 dBi.
This paper presents a MIMO cross array with azimuth-elevation combined beamforming. Compared to an M×N rectangular array with one-way and two-way beamforming, the number of required array elements could be reduced from M×N to M+N+4 so as to drastically reduce the system cost while maintain higher angular resolution performance. Compared to an M+N cross array with one-way and two-way azimuth-elevation...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.