Inductively coupled RF telemetry is an optimal method for both power supply and data transmission in long
term artificial implants due to small size, high reliability, and extended life span of the device. In this research,
we propose the use of the same technique for secure remote interrogation and powering of a human implantable,
Surface Acoustic Wave (SAW) correlation based, passive microvalve. This is carried out by interrogating the
microvalve with a Barker sequence encoded BPSK signal. In this paper we present the development of a FEM
model for the derivation of the induced voltage on a miniature (2.5×2.5×1 mm), inductively coupled, biocompatible
spiral antenna/coil, interrogated by a 7.5×7.5×0.2 cm spiral antenna/coil in the near field. The
amount of power transferred at a 30-160 MHz range was derived using the S21 coupling response when the two
antennas are separated by a human body simulant of 5 cm depth. Furthermore, the effect of varying magnetic
coupling on the induced voltage, due to the misorientation of coils/antennas is analysed.
KEYWORDS: Field programmable gate arrays, Digital signal processing, Telecommunications, Signal processing, Software development, System integration, Analog electronics, Wireless communications, Internet, Operating systems
In this paper we present an introduction to Cognitive RFID Integrated System Platform (CRISP), a framework for development and implementation of RFID communication protocols. The framework enables advanced research in the area of RFID wireless communication protocols and algorithms by interfacing a large class of experimental medium access control (MAC) with custom physical layer (PHY) implementations. As such, CRISP provides a flexible, scalable, configurable and high performance RFID research tool. The low level protocol handling routines are written in VHDL and higher level functions are programmed in C and targeted to embedded Microblaze soft-core processor within the Xilinx Virtex 5 class of FPGAs. Furthermore, the online open-access repository from The University of Adelaide is available to document and share different architecture and designs with other researchers in the field.
As wireless devices proliferate, more of these devices have to share a finite and increasingly limited amount of available radio spectrum. Currently, spectrum bands are used for a particular purpose that they are licensed for. However, these spectrums are not always used by their licensees or primary users, and as such are unused and are idle most of the time. These swath of unused frequency spectrum can be used by unlicensed users, when available, to mitigate the spectrum scarcity. In this article we study different methods of spectrum sensing in cognitive radio paradigm and compare them in terms of their potential interference with primary users.
Low power sensor nodes distributed over a large geographical area provide an economical way to collect environmental
information. The sensors can utilize backscatter signals to communicate with a central node without
significant power consumption. Each sensor can modulate its reflected backscatter signal by switching a load on
the sensor antenna. This allows design of low power sensor nodes with longer lasting battery life. The nodes can
be built to reradiate a harmonic of the received signal. This helps to avoid interference at the central node from
reflection from unwanted objects.
A passive harmonic reradiator is designed in this project to receive a 915 MHz electromagnetic wave and
reradiate at 1.83 GHz. The design consists of receiver antenna, transmitter antenna, a Schottky diode, and
matching network. Simulation and measurement results are provided. The results show promising characteristics
for the use of the device to track animals in wild life.
KEYWORDS: Field programmable gate arrays, Digital signal processing, Signal processing, Amplifiers, Software development, Modulation, UHF band, Oscillators, Operating systems, Manufacturing
The past few years have seen a significant shift in passive RFID tags performance and advancement. RFID standards have evolved, as users of technology proliferated across several industries. Innovation in the readers, however, has been very slow. But all that can change
by using software defined RFID readers. Being software based means that radios, terminals and networks are becoming reconfigurable and programmable. Research in software and cognitive radios is bringing rapid development. Even though these concepts are under active research, many challenges remain in making this vision a reality. In this work we study several aspects of a cognitive software based RFID reader, implementing a practical standards-compliant RFID reader using FPGA and off-the-shelf RF components. In this paper experimentation, implementation and theoretical work is described.
In this paper, we present and analyze the most fundamental constraint of RFID systems, power rectification. This issue plays an important role in development of long-range RFID systems. Rectifiers are the key components in power rectifications and efficiency of an RFID system. Therefore this paper is concentrated in investigating this major issue. To tackle this problem a novel Schottky Barrier Diode (SBD) has been proposed. The proposed SBD provides good power conversion rate and switching properties.
Passive radio frequency identification (RFID) systems deployment efforts are revolutionizing supply chain logistics by providing unprecedented supply chain visibility. The widely used bandwidth of operation in modern systems is the UHF ISM (industrial, scientific, and medical) band. The performance of UHF RFID systems are largely reliant on low power CMOS circuits, efficient power rectification and the ability of RFID label antennas to match to the input impedance of the RFID label IC. This paper examines a new rectifying structure and considers it for its merits in RFID applications while analysing contribution of the rectifying structure to the input impedance of RFID chips as this is an important consideration in impedance matching to an external antenna.
The evolution of RFID Systems has lead to the development of a class hierarchy in which the battery powered labels are a set of higher class labels referred to as active labels. The battery powering active transponders must last for an acceptable time, so the electronics of the label must have very low current consumption in order to prolong the life of the battery. However due to circuit complexity or the desired operating range the electronics may drain the battery more rapidly than desired but use of a turn-on circuit allows the battery to be connected only when communication is needed, thus lengthening the life of the battery.
Two solutions available for the development of a turn on circuit use resonance in a label rectification circuit to provide a high sensitivity result. This paper presents the results of experiments conducted to evaluate resonance in a label rectification circuit and the designs of fully integrable turn-on circuits. We have also presented test results showing a successful practical implementation of one of the turn on circuit designs.
While pseudo random number generators based on computational complexity are widely used for most of cryptographic applications and probabilistic simulations, the generation of true random numbers based on physical randomness is required to guarantee the advanced security of cryptographic systems. In this paper we present a method to exploit manufacturing variations, metastablity, and thermal noise in integrated circuits to generate random numbers. This metastability based physical random number generator provides a compact and low-power solution which can be fabricated using standard IC manufacturing processes. Test-chips were fabricated in TSMC 0.18um process and experimental results show that the generated random bits pass standard randomness tests successfully. The operation of
the proposed scheme is robust against environmental changes since it can be re-calibrated to new environmental conditions such as temperature and power supply voltage.
A hardware random number generator is different from a pseudo-random number generator; a pseudo-random number generator approximates the assumed behavior of a real hardware random number generator. Simple pseudo random number generators suffices for most applications, however for demanding situations such as the generation of cryptographic keys, requires an efficient and a cost effective source of random numbers. Arbiter-based Physical Unclonable Functions (PUFs) proposed for physical authentication of ICs exploits statistical delay variation of wires and transistors across integrated circuits, as a result of process variations, to build a secret key unique to each IC. Experimental results and theoretical studies show that a sufficient amount of variation exits across IC’s. This variation enables each IC to be identified securely.
It is possible to exploit the unreliability of these PUF responses to build a physical random number generator. There exists measurement noise, which comes from the instability of an arbiter when it is in a racing condition. There exist challenges whose responses are unpredictable. Without environmental variations, the responses of these challenges are random in repeated measurements.
Compared to other physical random number generators, the PUF-based random number generators can be a compact and a low-power solution since the generator need only be turned on when required. A 64-stage PUF circuit costs less than 1000 gates and the circuit can be implemented using a standard IC manufacturing processes. In this paper we have presented a fast and an efficient random number generator, and analysed the quality of random numbers produced using an array of tests used by the National Institute of Standards and Technology to evaluate the randomness of random number generators designed for cryptographic applications.
In this paper, we present and analyze the most fundamental constraint of RFID systems, power rectification. This issue plays an important role in development of long-range RFID systems. Rectifiers are the key components in power rectifications and efficiency of an RFID system. Therefore this paper is concentrated in investigating this major issue. To tackle this problem a novel Schottky Barrier Diode (SBD) has been proposed. The proposed SBD provides good power conversion rate and switching properties.
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