A. A. Serra

A Focused Planar Microstrip Array for 2.4 GHz RFID Readers

The specific problems encountered in the design of near-field focused planar microstrip arrays for RFID (Radio Frequency IDentification) readers are described. In particular, the paper analyzes the case of a prototype operating at 2.4 GHz, which has been designed and characterized. Improvements with respect to conventional far-field focused arrays (equal phase arrays) are discussed and quantified.

Multiband PIFA for WLAN mobile terminals

A novel compact planar inverted-F antenna (PIFA) to be mounted on laptop computers is presented. The proposed multiband single-feed PIFA simultaneously operates in the IEEE 802.11a, IEEE 802.11b/g, and HIPERLAN2 frequency bands. The multiband behavior is obtained by combining a trapezoidal feed plate with two different resonance paths in the radiating structure. The overall size of the antenna renders it suitable to be installed at the border of the display of a notebook. Simulation results are compared with measurements performed on an antenna prototype.

A Wide-Band Dual-Polarized Stacked Patch Antenna

A wideband dual-polarized slot-coupled stacked patch antenna operating in the UMTS (1920-2170 MHz), WLAN (2.4-2.484 GHz), and UMTS II (2500-2690 MHz) frequency bands is described. Measurements on a prototype of the proposed patch antenna confirm good performance in terms of both impedance matching and isolation

Diversity Measurements for On-Body Communication Systems

In this letter, preliminary measurements for the analysis of diversity techniques for on-body communication systems have been carried out, when both the transmitter and the receiver are placed on the body. A monopole antenna on a square ground plane has been used as a transmitting element and two monopoles on a common ground plane as a two-branch receiver. Measurements have been carried out in an anechoic chamber in order to verify the scattering and fading effects of the body itself on the radio communication channel. The acquired data have been postprocessed by resorting to different signal combining techniques, in order to evaluate the diversity performance. Measurement results in terms of diversity gain are shown for a number of typical on-body radio links, when different body postures are considered.

Detection and classification of human arm movements for physical rehabilitation

In the latest years, the detection of body posture and activity received a significant interest in the field of the physical rehabilitation aimed at providing advanced medical therapies to patients who have suffered a stroke, joint replacements/reconstructions, amputation, or some motor function disability resulting from Parkinsons disease [1,2]. Rehabilitation is a dynamic process and the restoration of patients functional capability to normal requires every day functional activities that need to be monitored and controlled by specialized medical operators. An effective approach is represented by motion capturing systems where some video cameras follow the movements of a number of markers placed on the human body to reconstruct its activity. However, such systems are complex, expensive and require a large number of constitutive elements (cameras and markers) [3].

A square ring slot feeding technique for dual-polarized patch antennas

A novel slot fed dual-polarized patch antenna using a square ring slot and a single layer laminate for the feeding network has been presented. Numerical results have shown that the symmetry properties of the slot-patch pair allow us to obtain good performance in terms of isolation and amplitude of the cross-polar components. Measurements on prototypes will be shown at the conference.

Channel model for on body communication along and around the human torso at 2.4GHz and 5.8GHz

A new trend in developing wireless sensors consists in using wearable wireless sensors to monitor human vital parameters, activities and movements. Characterizing the radio channel is an important issue to design a suitable communication system, especially when the propagating medium is the human body. To address this problem, on body measurements along and around the torso were performed. Two path loss models were analyzed considering the propagation channel characterization between two wearable devices placed on a human body, and operating at 2.4GHz and 5.8GHz. Wearable wireless low-cost commercial modules and low profile annular ring slot antennas were used as transceivers Measurement results were compared with CST Microwave Studio simulations using simplified body models like spherical and ellipsoidal geometries.

Experimental investigation of diversity techniques for on-body communication systems

In this work, an experimental investigation of the application of a diversity scheme in on-body high-rate communication systems is presented. In these days, diversity is widely applied at base station receivers of mobile cellular systems and recent studies have been conducted on portable devices. At the best of the authors knowledge, no experimental or simulated analysis for diversity on on-body systems is available in the scientific literature. Diversity scheme performances are evaluated in terms of the diversity gain and all measurements have been carried out at 2.45 GHz (ISM frequency band).

A dual-band antenna for wireless communication terminals

The paper presents a relatively new dual band small size F-shaped antenna (Wong, K.L., Planar Antennas for Wireless Communications, John Wiley & Sons Inc., 2003; Yeh, S.H. and Wong, K.L., IEEE Antennas and Prop. Soc. Int. Symp., vol.1, p.72-5, 2002), and analyzes its installation on a side of the monitor of a portable computer. This implies that is necessary to design an antenna less than 15 mm wide. The antenna operates at the IEEE 802.11a (5.15-5.35 GHz) and the IEEE 802.11b (2.4-2.48 GHz) frequency bands. Samples of numerical results are shown, which have been calculated by resorting to a numerical code based on a method of moments (MoM).

A wearable multi antenna system on a life jacket for Cospas Sarsat rescue applications

In this paper, a multi antenna system mounted on a life jacket for human rescue Cospas Sarsat applications is described. The latter is intended to provide a earth to satellite SOS communication in case of shipwrecks or similar crashes and it is currently implemented in emergency devices like buoys. In the proposed work, two dipoles have been attached on different floating elements of a life jacket, in order to form a wearable emergency system that could be worn by any survivor. The two antennas are folded meandered dipoles operating at 406 MHz, center frequency of the Cospas sarsat system. A metallic sheet is used to shield the antennas from the human body and it is placed on the opposite side of the floating element with respect to each antenna. Antennas are linearly polarized with good impedance matching also when they are worn by the user, a wide radiation pattern beam and a high gain. Moreover they are orthogonal in order to form a diversity pattern transmitting system. Prototypes have been realized and a measurement campaign has been carried out showing good performance.