Design of Multi-Antenna System for UMTS Clamshell Mobile Phones with Ground Plane Effects Considerations

In this paper, the influence of the ground plane dimensions on the port-to-port isolation of two closely-spaced Universal Mobile Telecommunications System (UMTS) Planar Inverted-F Antennas (PIFAs) with and without neutralization line is first presented. Parametric studies show the existence of an optimal size of the ground plane allowing optimizing the isolation and the efficiency of the considered antenna-system. The results obtained with this study are used in the second part to develop an efficient neutralized multi-antenna system for clamshell-type mobile phones. The obtained results, in terms of isolation, matching and diversity for the two possible configurations of the clamshell system in use namely the open and the closed states, show that good performance are obtained in the open state and preserved in the closed state. Prototypes of these two configurations are realized and measurement results are in good agreement with the simulations

Recovering handset diversity and MIMO capacity with polarization-agile antennas

Journal ArticleDesign guidance is provided for multiple-input-multiple- output (MIMO) antenna systems on handsets-a strong prospect for next generation wireless devices. Handheld wireless devices are likely to be rotated out of their optimal polarization, thereby experiencing significant power losses. An existing polarization-agile antenna design and a novel four-spoke extension recover significant fractions of the rotation-induced losses both in switched-antenna diversity and capacity calculations-all but 1 dB of diversity gains at a 99% system reliability, half of the CΕ losses or 80% of the Cο,1 losses. These gains benefit four- and ten-element arrays and remain significant in the presence of 6 dB cross coupling and in volume-restricted arrays. Diversity order investigations also demonstrate a new, non-Rayleigh locus of curves describing patch antennas subject to rotation

Closed-form design equations for decoupling networks of small arrays

Small element spacing in compact arrays results in strong mutual coupling between the array elements. A decoupling network consisting of reactive cross-coupling elements can alleviate problems associated with the coupling. Closed-form design equations for the decoupling networks of symmetrical arrays with two or three elements are presented

Threshold Receiver Model for Throughput of Wireless Devices with MIMO and Frequency Diversity Measured in Reverberation Chamber

We present a simple theoretical model for the throughput data rate of a wireless LTE device including the improvements of data rate due to diversity in frequency (OFDM) and spatial domains (MIMO) under frequency selective fading. The model is based on defining an ideal threshold receiver for the line-of-sight (LOS) case, corresponding to reception with advanced error-correcting codes. The theoretical throughput model is in agreement with measurements in a reverberation chamber of a commercial LTE device for the 1 x 2 SIMO case, both regarding diversity and MIMO array gains, and it can therefore be used to complement measured results in evaluation of performance of LTE devices

A Millimeter Wave MIMO Testbed for 5G Communications

This paper presents a 2 x 2 millimeter wave (mm-wave) multiple-input-multiple-output (MIMO) testbed that operates at around 30 GHz. The link assessment of the system operating at 26.25 GHz was carried out on a test bench, with a short communication distance between the transmitting and receiving antennas. A user-programmable, reconfigurable and real-time signal processing field-programmable gate arrays (FPGAs)-based software defined radio (SDR) system was employed as part of the testbed to validate the system-level performance for a downlink time division long-term evolution (TD-LTE) duplex scheme. Constellation diagram for quadrature phase shift keying (QPSK) digital modulation were acquired while the testbed was operating at 30 GHz. The testbed could be employed for the development of signal test, communication algorithm and measurement metrology for 5G communications.Comment: 89th ARFTG Microwave Measurement Conference (ARFTG 2017

Effect of user presence on receive diversity and MIMO capacity for rayleigh-fading channels

The effects of the presence of the user on multipleinput– multiple-output (MIMO) performance for wireless communications systems is investigated through measurements in a reverberation chamber. Measured results have demonstrated that despite a decrement on the envelope correlation coefficient, a degradation of both diversity gain and MIMO capacity are expected when the user is present. While the validity of the correlation coefficients for predicting MIMO performance is limited in the presence of the user, the effects have also been found to be strongly dependent upon frequency, antenna topology, and user characteristics.This work was supported in part by the Fundación Séneca, the R&D coordinating unit of the Autonomous Region of Murcia (Spain) under Projects 2I05SU0033 and TIC-TEC 06/01-0003

The influence of efficiency on receive diversity and MIMO capacity for rayleigh-fading channels

A previously published guideline for MIMO antenna arrays is refuted. The influence of radiation efficiency on diversity gain and MIMO capacity of wireless communications systems is investigated through simulations and measurements using a reverberation chamber. Integrated antennas on a portable device have efficiencies low enough to disallow typical inter-element correlation assumptions. Both diversity gain and MIMO capacity depend on the number of antennas, SNR and efficiency in a complex way. When the efficiency of antennas is considered, certain system capacity losses are predicted and measured. These losses may be recovered through using more receive elements than commonly recommended or through the addition of a smaller number of more efficient antennas.This work was supported in part by the Fundación Séneca, the R&D unit of the Autonomous Region of Murcia (Spain) under project references TIC-TEC 06/01-0003, 07/02-0005 and 05746/PI/07, and in part by the Spanish National R&D Programme through TEC2007/63470/TCM

Active textile antennas in professional garments for sensing, localisation and communication

New wireless wearable monitoring systems integrated in professional garments require a high degree of reliability and autonomy. Active textile antenna systems may serve as platforms for body-centric sensing, localization and wireless communication systems, in the meanwhile being comfortable and invisible to the wearer. New design strategies combined with dedicated signal processing techniques greatly enhance the robustness of these systems. On the one hand, the large amount of real estate available in public regulated services' garments may be exploited to deploy multiple textile antennas. On the other hand, the size of each radiator may be designed large enough to ensure high radiation efficiency when deployed on the body. This antenna area is then reused by placing active electronics directly underneath and energy harvesters directly on top of the antenna patch. We illustrate this design paradigm by means recent textile antenna prototypes integrated in professional garments, providing sensing, positioning and communication capabilities

On-body wearable repeater as a data link relay for in-body wireless implants

Wireless medical devices implanted at different locations in the human body have a wide application range. Yet, high-data-rate communication in the 2.4-GHz Industrial, Scientific, and Medical band suffers from high in-body attenuation loss. Link improvement cannot be obtained by simply increasing transmit power, as battery life is limited and in-body absorption has to remain low. To overcome these problems, a flexible on-body textile patch antenna, robustly matched directly to the human body, is designed and developed as part of a wearable repeater, enhancing communication with implanted wireless devices. This receive antenna, which can cope with different morphologies and patient movements, enables reliable high data rate and low-power communication links with an implant. A data link measurement is performed for the on-body repeater system placed on the human torso, relaying the signals to nearby medical equipment, without wired connection to the patient. The performance of the data link is experimentally assessed in different measurement scenarios. For a repeater system relying on simple analog amplification, which is low-cost, energy-efficient, and can be fully integrated into clothing, excellent results are obtained, with an average measured signal-to-noise ratio of 33 dB for tissue depths up to 85 mm