Ibra Dioum

Bio: Ibra Dioum is an academic researcher from Cheikh Anta Diop University. The author has contributed to research in topics: MIMO & Antenna (radio). The author has an hindex of 5, co-authored 32 publications receiving 147 citations. Previous affiliations of Ibra Dioum include École Normale Supérieure.

A Novel Compact Dual-Band LTE Antenna-System for MIMO Operation

Abstract: In this communication, we present a novel compact dual-band antenna-system for LTE multi-input and multi-output (MIMO) mobile handsets. The radiators consist of 3D Inverted-F- Antennas (IFAs) folded on the non-metalized part of the Printed Circuit Board (PCB) and operating in the LTE 700 MHz band. A parasitic radiating element is also attached to the IFAs to operate in the LTE 2.5-2.7 GHz band. Two antennas are placed on a realistic PCB (100 × 40 mm2) for MIMO operation. Various antenna configurations are tested when moving their position on the PCB. Based on the highest port-to-port isolation criterion, two configurations are adopted and their performances are compared. Both simulated and measured results are shown to illustrate the MIMO capabilities of the proposed structures.

Compact dual-band monopole antenna for LTE mobile phones

Abstract: In this paper, we present a dual-band antenna for Long Term Evolution (LTE) handsets. The proposed antenna is composed of a meandered monopole operating in the 700 MHz band and a parasitic element which radiates in the 2.5–2.7 GHz band. Two identical antennas are then closely positioned on the same 120×50 mm2 ground plane (Printed Circuit Board) which represents a modern-size PDA-mobile phone. To enhance the port-to-port isolation of the antennas, a neutralization technique is implemented between them. Scattering parameters, radiations patterns and total efficiencies are presented to illustrate the performance of the antenna-system.

Dual-band monopole MIMO antennas for LTE mobile phones

Abstract: In this paper, we present the design of a dual-band antenna for Long Term Evolution (LTE) handsets. The proposed antenna is composed of a meandered monopole operating in the 700 MHz band and a connected parasitic radiating in the 2.5 – 2.7 GHz band. Two antennas of the same kind are then closely positioned on the same 120×50 mm2 Printed Circuit Board (PCB) which represents a modern PDA-mobile phone. To enhance their port-to-port isolation, a neutralization technique is implemented between the two antennas. Scattering parameters, radiations patterns and efficiencies are presented to prove the usefulness of the method.

Miniature MIMO Antennas for 5G Mobile Terminals

Abstract: In this paper, we present the design and the measurement of a miniature MIMO dual-band (2.6/3.6 GHz) antenna array for future 5G handsets. The antenna element has a compact area with size of 10.5×14.5 mm2. The proposed antenna array elements are symmetrically placed along the long edges of the smartphone, and they are composed of four same antenna types. Two antennas of the same kind are then closely positioned on the same 120×50 mm2 Printed Circuit Board (PCB). The initial proposed handset-system is composed of U-Shape structure and a connected meandered monopole. Both simulated and measured results are shown to illustrate the MIMO capabilities of the proposed structures. These results show that the presented structure operate in dual-band at 2.5–2.7 GHz and 3.4–3.8 GHz, which has a bandwidth of 200 MHz and 400 MHz respectively for reflection coefficient less than −6dB. The port isolation is more than 11.5 dB across the whole band of interest without using any decoupling network for two antenna structures. The antenna is fabricated using FR4 substrate with relative permittivity of 4.4 and pert tangent of 0.02.

Comparison of Random Forest and Extreme Gradient Boosting Fingerprints to Enhance an indoor Wifi Localization System

Abstract: Machine Learning framework adds a new dimension to the localization estimation problem. It tries to find the most likely position using processed features in a radio map. This paper compares the performance of two machine learning tools, Random Forest (RF) and Extreme Gradient Boosting (XGBoost), in exploiting the multipath information for Indoor localization problem. The investigation was carried out in a noisy indoor scenario, where Non-Line-Of-Sight (NLOS) between target and sensors may affect the location of Wi-Fi Access point strongly. It is possible to improve the position system performance by using fingerprints techniques that employ multipath information in a Machine Learning framework, which operates a dataset generated by real time. Usually, real measurements produce the fingerprints localization features, and there is mismatching with the simulated data. Another drawback of NLOS features extraction is the noise level that occurs in position processing. Random Forest algorithm uses fully grown decision trees to classify possible emitter position, trying to achieve error mitigation by reducing variance. On the other hand, XGBoost approach uses weak learners, defined by high bias and low variance. The results of the simulation show that XGBoost reaches a Mean Square Error (MSE) of 1.77m while RF has 1.83m, as shown in Fig. (4). In real time analysis, 40 points were used for testing. RF has an MSE 1.85m and XGBoost has 1.82m. The results are compared to the state of the art and recently published papers.

Antennas in Cellular Phones for Mobile Communications

Abstract: The mobile industry has experienced a dramatic growth; it evolves from analog to digital 2G (GSM), then to high date rate cellular wireless communication such as 3G (WCDMA), and further to packet optimized 3.5G (HSPA) and 4G (LTE and LTE advanced) systems. Today, the main design challenges of mobile phone antenna are the requirements of small size, built-in structure, and multisystems in multibands, including all cellular 2G, 3G, 4G, and other noncellular radio-frequency (RF) bands, and moreover the need for a nice appearance and meeting all standards and requirements such as specific absorption rates (SARs), hearing aid compatibility (HAC), and over the air (OTA). This paper gives an overview of some important antenna designs and progress in mobile phones in the last 15 years, and presents the recent development on new antenna technology for LTE and compact multiple-input-multiple-output (MIMO) terminals.

Dual-Helicity Decoupled Coding Metasurface for Independent Spin-to-Orbital Angular Momentum Conversion

Abstract: Controlling the conversion of light's spin angular momentum to orbital angular momentum (OAM) is crucial for applications, including optical systems and wireless communication. In this regard, metasurfaces are often limited by the difficulty of producing independent spin-to-OAM conversions. This study uses a reflective, dual-helicity decoupled coding metasurface to realize completely independent control of OAM vortices for two orthogonal helicities, achieving a free combination of distinctive OAM topological charges, arbitrary helicity, anomalous scattering, and complex spatial beam editing. These results could help to integrate versatile functionalities for advanced compact systems.

Multiband MIMO Antenna for GSM, DCS, and LTE Indoor Applications

Abstract: A novel and compact planar multiband multiple-input-multiple-output (MIMO) antenna is presented. The proposed antenna is composed of two symmetrical radiating elements connected by neutralizing line to cancel the reactive coupling. The radiating element is designed for different frequencies operating in GSM 900 MHz, DCS 1800 MHz, LTE-E 2300 MHz, and LTE-D 2600 MHz, which consists of a folded monopole and a beveled rectangular metal patch. The presented antenna is fed by using 50-Ω coplanar waveguide (CPW) transmission lines. Four slits are etched into the ground plane for reducing the mutual coupling. The measured results show that the proposed antenna has good impedance matching, isolation, peak gain, and radiation patterns. The radiation efficiency and diversity gain (DG) in the servicing frequencies are pretty well. In the Ericsson indoor experiment, three kinds of antenna feed systems are discussed. The proposed antenna shows good performance in Long Term Evolution (LTE) reference signal receiving power (RSRP), download speed, and upload speed.

Dual-Band Printed Fractal Monopole Antenna for LTE Applications

Abstract: In this letter, a dual-band fractal monopole antenna suitable for Long Term Evolution (LTE) standard is proposed. The antenna geometry is based on a perturbed planar Sierpinski fractal shape, whose geometrical descriptors are determined by means of a particle swarm optimization (PSO). The optimized antenna exhibits a good impedance matching within the LTE bands at 700 and 2600 MHz as well as a 24% size reduction with respect to a standard quarter-wave resonant monopole. The efficiency of the proposed antenna is assessed by means of both simulations and measurements.

A Transmission-Line-Based Decoupling Method for MIMO Antenna Arrays

Abstract: A transmission-line-based decoupling technique for dual-polarized multiple-input and multiple-output (MIMO) antenna arrays is presented and analyzed. The proposed scheme enables well-canceled coupling for the adjacent elements under co-polarization, without degrading the isolation of the cross-polarized ports. First, a decoupling network based on the presented method for a $2 \times 2$ MIMO array is provided, along with a comprehensive design procedure. Calculations and simulations are operated to verify decoupling performance. For further verification, a $2 \times 2$ dual-polarized patch array with the proposed decoupling method is developed. The decoupling network characterizes low profile, compact size, and low insertion loss, which is realized in a single layer. Measurements denote that the isolations between the co-polarized elements are improved from 16 to 20 dB to over 30 dB after decoupling at the center frequency of 2.45 GHz. Subsequently, based on the proposed $2 \times 2$ decoupling method, a decoupling network for large-scale dual-polarized MIMO arrays is presented. A design example of a $4 \times 4$ dual-polarized patch antenna array is established. Full-wave simulations indicate that the isolations are enhanced to better than 30 dB with a small insertion loss of less than 0.45 dB and can widely be used for phased array and massive MIMO array systems.