Design and Performance Study of a Dual-Element Multiband Printed Monopole Antenna Array for MIMO Terminals

This letter presents a study on linearly polarized compact multiband multiple-input-multiple-output (MIMO) antenna system for small mobile terminals. The MIMO antenna system consists of two symmetric printed monopole antennas with edge-to-edge separation of 0.097 λ 0 at 900 MHz. Each antenna element has a capacitive feed and is composed of two twisted lines, a parasitic loop, and a shorting trip that generate five resonant modes around 900, 1800, 2100, 3500, and 5400 MHz, covering GSM850/900, DCS, PCS, UMTS, WLAN, and WiMAX frequency bands. Two inverted-L shaped branches and a rectangular slot with one circular end, etched on the ground plane, were introduced to improve the isolation between antenna elements. The isolation achieved is higher than 15 dB in the lower band and 20 dB in the upper bands, leading to an envelope correlation coefficient of less than 0.025. The simulated performance of the designed antenna system has been verified in the experiment

Impulse Radio-Ultra Wideband Communications for Localisation and Tracking of Human Body and Limbs Movement for Healthcare Applications

Accurate and precise motion tracking of limbs and human subjects has technological importance in various healthcare applications. The use of Impulse Radio Ultra Wideband (UWB) technology due its inherent properties is of recent interest for high accuracy localisation. This paper presents experimental investigations and analysis of indoor human body localisation and tracking of limb movements in 3D based on IR-UWB technology using compact and cost-effective body worn antennas. The body–centric wireless channel characterisation has been analysed in detail using parameters such as path loss magnitude, number of multipath components, RMS delay spread, signal amplitude and Kurtosis with the main focus to differentiate between line-of-sight (LOS) and non-line-of-sight (NLOS) situations. Fidelity of the received signal is also calculated for different activities and antenna positions to study the pulse preserving nature of the UWB antenna when it is placed on the human body. The results reported in this paper have high localisation accuracy with 90 % in the range of 0.5 to 2.5 cm using simple and cost-effective techniques which is comparable to the results obtained by the standard optical motion capture system

UWB Channel Characterization for Compact L-Shape Configurations for Body-Centric Positioning Applications

This paper presents an analysis on the body-centric channel parameters classification for various compact 3 base station L-Shape configurations utilizing only a 2D-plane for installation. Four different L-Shape configurations (x-z/y-z plane) are studied (facing-front/side/back) by varying the position of the base stations in an indoor environment. Results and analyses highlight the variation of the channel parameters with respect to the orientation of the base station configurations and presence of the human subject. Channel parameters values (peak power delay profile (PDP)/rms delay spread sigma/Kurtosis) are reported for (line of sight (LOS): -65 to -50 dB/0.5-5 nsec/40-60) and (non-line of sight (NLOS): -80 to -65 dB/ 10-25 nsec/ 5-25). The 3D localisation accuracy obtained is highest (1-3 cm) for the x-z plane L-Shape configuration facing-front which has maximum number of LOS links (70%).The accuracy decreases by 1-2 cm for the x-z plane L-Shape configuration facing-back due to increase in NLOS links (70%) between the wearable antennas and the base stations

Design of a compact multiband circularly polarized antenna for global navigation satellite systems and 5G/B5G applications

Design of a multiband circularly polarized antenna is proposed in this article. The antenna has a simple and compact form factor by employing single‐feed stacked patch structure. It exhibits good performance at the global navigation satellite system (GNSS) frequency bands of L1, L2, and L5 and cellular communications frequency band of 2.3 GHz. The antenna has a 3‐dB axial ratio bandwidth of 1.1%, 1.0%, 4.1%, and 1.5% at the four operating bands of L1 (1.575 GHz), L2 (1.227 GHz), L5 (1.176 GHz), and 2.3 GHz. The antenna also achieves a gain of more than 2.2 dBiC and efficiency of more than 70% at the four frequencies. A detailed parametric study is carried out to investigate the importance of different structural elements on the antenna performance. Results are verified through close agreement of simulations and experimental measurements of the fabricated prototype. Good impedance matching, axial ratio bandwidth, and radiation characteristics at the four operating bands along with small profile and mechanically stable structure make this antenna a good candidate for current and future GNSS devices, mobile terminals, and small satellites for 5G/Beyond 5G (5G/B5G) applications

Localization of Wearable Ultra Wideband Antennas for Motion Capture Applications

This paper presents a study of human body localisation using Ultra Wideband (UWB) technology. Various base station configurations, time of arrival and first peak detection algorithms are used to estimate the position of body-worn antennas. Localisation error as small as 1-2 cm has been achieved using 8 base stations which is comparable to the measurement accuracy obtained by complex optical motion capture system to determine the absolute displacement error. The localisation error obtained is better by a third in comparison to common commercial system based on UWB technology. The results demonstrate that Cuboid-shape configuration with 4 base stations gives slightly low average percentage error (2 to 3%) in comparison to Y-shape (4%). However, the Y-shape configuration is more compact and provides setting up simplicity, which makes it convenient for various applications ranging from healthcare monitoring to entertainment technologies either laboratory based or in-home

Analysis of ring and rectangular slot FSS using a new equivalent circuit method

A new method which uses the spatial modal decomposition of the single FSS element has been applied for the analysis of a thin frequency selective structure (FSS) composed of rectangular slot elements. The method is based on the equivalent circuit approach and has exhibited more accurate results compared with conventional equivalent circuit approaches. In addition the method performs much faster compared to rigorous solutions. A good agreement in comparison with other methods and measurements has been revealed for several kinds of thin FSS