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Many radio transceivers provide an instantaneous measure of radio-frequency (RF) energy through their received signal strength indicator (RSSI) output. Applications of this measurement include media access control (MAC), e.g., implemented as listen-before-talk (LBT), and location estimation. Factors both internal and external to wireless devices may significantly impact these measurements, and much...
We report the results of several field experiments to characterize broadband UHF radiofrequency propagation through mountainous terrain and into deep shadow zones. Utilizing an existing digital broadcast television station (center frequency 497 MHz with a standard 6 MHz bandwidth) as our signal source, we performed spectrum analyzer surveys to determine both spatial and spectral characteristics of...
A concurrent multi-band RF system to detect and analyze the human vital signs for search and rescue of human life during natural calamities is reported in this paper. The proposed system simultaneously operates at 2.44-/5.25-GHz and is comprehended with indigenously developed dual-band subsystems and commercial laboratory equipments. The human vital signs are captured at a distance of 0.5m from the...
The paper entitled Low-Cost FPGA Based Antenna Pattern Measurement System describes a cost-effective antenna pattern measurement system for educational purposes. Operating the system does not require any additional computer support as it is designed to be a standalone device. The system is built upon Field Programmable Gate Array (FPGA) platform and contains 4 main blocks; namely, RF source, logarithmic...
An UWB low power active transmitter operating in the European UWB band (6–8.5 GHz) is presented, which may find applications in RFID transponders with asymmetric downlink and uplink communication, as well as in others communication devices. It is based on a 7.25 GHz oscillator driven by a base-band pulse generator, and connected to a small size UWB antenna. The oscillator is turned on and off by the...
This paper presents the first 16-element wafer-scale phased array transmitter with scanning in both the E-and H-planes. The chip integrates a 108–112 GHz source, together with a 1∶16 distribution network, amplifiers, 2-bit phase shifters on each cell, and an on-chip high efficiency differential dipole antenna. Measured patterns show scanning to +/−30° in both planes, and agree well with simulations...
This paper presents, for the first time, a low cost, 60 GHz, RF front-end Tx/Rx integrated with a Yagi-Uda antenna array on organic Liquid Crystal Polymer substrate. The Tx/Rx module consists of a GaAs LNA, PA and a Single Pole Double Throw (SPDT) switch wirebonded on a single, multilayer substrate. The array was designed for operation at 60.6 GHz with a gain of 12.1 dBi. The radiation pattern measurements...
LINC (Linear amplification with Nonlinear Components) is a power amplifier linearization technique which can provide good linearity and amplification efficiency but low system efficiency due to the power combiner. In this article, we propose to remove the power combiner and to study the performance of the modified architecture system. Measurement results show an efficiency improvement by 400% compared...
The goal of the work is to investigate the Radio Frequency (RF) propagation of ZigBee devices operating within a hospital environment to analyze their real indoor behaviour to design healthcare systems. Different Received Signal Strength Inidcation (RSSI) measurement campaigns have been carried out to characterize the main propagation features. On the basis of the experimental results it has been...
This paper describes configurable, 3.6 to 7.5 GHz pulse UWB transmitter IC targeted for neurological implants with high data rate requirements. Each cycle of the RF pulse is digitally programmable in amplitude and duration, enabling a very flexible shaping of the transmitted PSD signal, without the use of an output filter. The transmitter achieves a maximum of 34% of energy efficiency when drawing...
A 60-GHz band phased array transmitter is developed based on 90-nm CMOS process featuring compact baseband phase shifters with ideally zero power consumption. The phase shifter changes an RF signal phase every pi/2 by switching baseband signal paths. The transmitter has 6 RF front-ends and 6 phase shifters to implement beam steering function for a 1 times 6 array antenna system. Each of the RF front-ends...
Most existing work on dynamic spectrum access deals with creating a spectral and temporal map of spectrum white space, and then filling it. The spectrum can be better utilized by increasing the spatial awareness of secondary users to include knowledge of the locations of all primary and secondary users, as well as the orientations and parameters of their directional or omni-directional antennas. This...
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