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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(More)
Positioning algorithms in cellular networks has become increasingly important as a means of supporting emerging services that require a sufficiently precise estimation of the position of the mobile terminal (MT) associated with a given base station (BS). Currently, even the most sophisticated positioning algorithms require at least three BSs to achieve(More)
A detailed performance analysis of near-field-focused planar arrays is addressed. Design curves and performance data are shown for planar square arrays as a function of the array size, the inter-element distance, and the focal distance. The performance curves are compared with results presented in earlier studies relevant to continuous-aperture antennas, as(More)
Body-centric communications is an important part of fourth-generation personal communications systems. Like the mobile cellular communication channel, on-body communication channels are affected by fading. In this paper, the effect of diversity for on-body communication channels is investigated. Measurements were taken in both an anechoic and typical indoor(More)
A new phase-based technique for localization and tracking of items moving along a conveyor belt and equipped with ultrahigh frequency-radio frequency identification (UHF-RFID) tags is described and validated here. The technique is based on a synthetic-array approach that takes advantage of the fact that the tagged items move along a conveyor belt whose(More)
The design of a reflectarray antenna is presented when the radiated field is focused in the near-zone of the array aperture. In particular, the reflectarray antenna is implemented for RFID reader applications at 2.4 GHz. Numerical investigations on the radiation characteristics of this reflectarray, as well as an experimental validation, are presented to(More)
A compact, low-profile, two-port dual-band circularly polarized (CP) antenna for portable RFID readers is presented. The radiating element for the UHF-RFID band (902-928 MHz) has been realized through a circular array of four inverted-F meandered monopoles, where the array elements are excited with a 90 <sup>&#x00B0;</sup> phase offset (sequential rotation(More)
Circularly polarized antennas are used in 2.4 GHz ZigBee radio modules to evaluate performance improvement of RSSI (Received Signal Strength Indicator) based location techniques, with respect to conventional linearly polarized antennas. Experimental RSSI measurements in an indoor environment clearly show that multipath fading is significantly reduced when(More)
We examine the indoor single-room localisation problem while using multiple fixed transmitters (anchors) and multiple mobile receivers placed on the user (mobiles). Anchors transmit a periodic beacon that the mobiles receive and of which they measure the received power level value (RSSI). Using this information only, which requires no specialised hardware,(More)
In this letter, a technique to measure heartbeat and respiration rates through a single on-body antenna is addressed. The main idea is to extract the cardiopulmonary information induced on the reflection coefficient of a single antenna placed in proximity of the human thorax. As a preliminary step, phase samples of the antenna reflection coefficient have(More)