Low-power frequency-conversion based temperature sensor for long-range passive RFID sensor applications.

A low-power frequency-conversion based temperature sensor interface optimized for passive UHF RFID applications have been designed and implemented. The interface is based on a reference capacitor that is charged by a temperature dependent current and discharged by a hysteresis loop. The circuit has been implemented in a standard CMOS 180nm process. The post-layout simulations show that the presented architecture is able to compensate for variations on the bandgap reference and cover a wide temperature range (140oC) with minimum active area (0:019mm2), reduced power consumption (-= 6:5gammaW), and reduced effect of PVT variations, accomplishing the design objectives

A 5.8-GHz-Direction of an arrival localization radio system with a reconfigurable monopole antenna array.

This article presents the design of a complete radio system receiver to detect, in real time, the direction of arrival (DOA) of an incoming industrial, scientific, and medical (ISM)-band signal at 5.8 GHz. When a transmitter continuously sends a binary phase-shift keying (BPSK), modulated pseudo-noise (PN) code, the receiver estimates the DOA based on the received signal strength (RSS) and performs the channel sounding. The device that we describe includes a pattern-reconfigurable monopole antenna array, a front end, and a systemon-module (SOM). The SOM controls the antenna's main lobe direction by positive-intrinsic-negative (p-i-n) diode switching, configures the front-end modules, completes the data acquisition, and performs the digital signal processing (DSP) for the DOA estimation. The system has an average DOA resolution of 90° in the horizontal plane, with a success rate higher than 90%. It is presented as an educational platform for electrical engineering undergraduate and M.S. degree students