Leonid Mats

Powering autonomous cubic-millimeter devices

The reported results are concerned with powering miniature autonomous devices using radio-frequency (RF) energy, not requiring batteries or wires. The century-old concept of transmitting energy using RF is now practical for numerous applications. The method of evaluating the receiving area of miniature antennas is presented, and implemented using a particular antenna profile with inherent electrical inductance and capacitance properties. The research demonstrates the ability to obtain the theoretical antenna effective area. The results facilitate the economical fabrication of an antenna as an integral part of a printed circuit board or complementary metal-oxide-semiconductor (CMOS) device

The In-Situ Technique for Measuring Input Impedance and Connection Effects of RFID Tag Antenna

In this paper, an indirect noninvasive method for measuring input impedance and the variations in the assembly of the interconnect and packaging between antenna and the integrated circuit (IC) effects of passive radio frequency identification (RFID) transponder (tags) antennas is presented. The analysis of different RFID tags is presented together with the experimental data.

Radio frequency identification prototyping

While RFID is starting to become a ubiquitious technology, the variation between different RFID systems still remains high. This paper presents several prototyping environments for different components of radio frequency identification (RFID) tags to demonstrate how many of these components can be standardized for many different purposes. We include two active tag prototypes, one based on a microprocessor and the second based on custom hardware. To program these devices we present a design automation flow that allows RFID transactions to be described in terms of primitives with behavior written in ANSI C code. To save power with active RFID devices we describe a passive transceiver switch called the “burst switch” and demonstrate how this can be used in a system with a microprocessor or custom hardware controller. Finally, we present a full RFID system prototyping environment based on real-time spectrum analysis technology currently deployed at the University of Pittsburgh RFID Center of Excellence. Using our prototyping techniques we show how transactions from multiple standards can be combined and targeted to several microprocessors include the Microchip PIC, Intel StrongARM and XScale, and AD Chips EISC as well as several hardware targets including the Altera Apex, Actel Fusion, Xilinx Coolrunner II, Spartan 3 and Virtex 2, and cell-based ASICs.

Exploring RFID Prototyping in the Virtual Laboratory

This paper describes several RFID technology related course topics dealing with antenna design, protocol design, and implementation strategies accessed from a centralized system for students to access. By utilizing the central system, students from multiple universities can share a single piece of equipment and still learn about the underlying RFID technology. Additionally, by creating this interface system, the necessary features for RFID development can be made available to students and instructors need not learn every single detail of complicated equipment to effectively teach students to work with RFID technology

A design automation and power estimation flow for RFID systems

While RFID has become a ubiquitous technology, there is still a need for RFID systems with different capabilities, protocols, and features depending on the application. This article describes a design automation flow and power estimation technique for fast implementation and design feedback of new RFID systems. Physical layer features are described using waveform features, which are used to automatically generate physical layer encoding and decoding hardware blocks. RFID primitives to be supported by the tag are enumerated with RFID macros and the behavior of each primitive is specified using ANSI-C within the template to automatically generate the tag controller. Case studies implementing widely used standards such as ISO 18000 Part 7 and ISO 18000 Part 6C using this automation technique are presented. The power macromodeling flow demonstrated here is shown to be within 5% to 10% accuracy, while providing results 100 times faster than traditional methods. When eliminating the need for certain features of ISO 18000 Part 6C, the design flow shows that the power required by the implementation is reduced by nearly 50%.

Statistical Analysis of Transponder Packaging in UHF RFID Systems

Packaging of RFID transponders that operate at ultrahigh frequencies (UHF) requires nontraditional materials and innovative methods in order to make a functional, reliable, and inexpensive RFID transponders. Presented is a statistical analysis along with the model as the way to evaluate measured results and provide the quality and process control for the electrical and mechanical performance of the packaging of RFID tags with respect to different manufacturing processes. The power analysis is presented in support of the statistical analysis and the sample size selection.

Analysis and Synthesis of RFID Equivalent Circuits through Backscatter and ARS

RFID tags are assumed to function when being read and not to function when the reader does not see the tag. In actuality, the antenna/front end combination is an analog circuit that represents the result of both design and manufacturing. This circuit is a determinant in the minimum power to operate the manufactured tag. Other wireless devices such as passive sensor platforms require similar designs. This paper presents a method of analysis and considerations for design of passive devices that share similar front end structures with a focus on passive RFID tags.

In-Situ characterization of passive rfid tag performance at absolute minimum power levels

This paper presents a novel alternative approach for non-invasive characterization and evaluation of the passive RFID tag performance. This method will provide a reader-independent measure of tags performance using a vector network analyzer (VNA), which is a fundamental commercial RF measuring instrument that can be accurately calibrated.