Microwave RFID Research Articles

Design of Compact Balanced-to-Balanced Diplexer Using Dual-Mode CRLH Resonator for RFID and 5G Applications

A compact balanced-to-balanced diplexer based on composite right/left-handed (CRLH) resonator is presented in this paper. The proposed compact CRLH resonator is used to design two balanced channels, which are connected by T-junction to construct the balanced-to-balanced diplexer. Under differential-mode (DM) operation, the proposed CRLH resonator can provide two adjacent DM resonant modes to produce one passband of the balanced-to-balanced diplexer. Under common-mode (CM) operation, the CRLH resonator also generate two CM resonant modes, whose locations are far away from DM resonant modes, resulting in a perfect CM suppression level. To verify the design methodology, a compact balanced-to-balanced diplexer operated at 2.45 GHz and 3.47 GHz is designed and fabricated for multi-service system integrated with microwave RFID and 5G applications. The proposed balanced-to-balanced diplexer shows high CM suppression level and channel-to-channel isolation performance. The measured results are agree well with the simulated ones.

RFID 리더의 주파수 조정을 통한 태그 위치 센싱

UHF and microwave RFID systems are widely applied in various fields because they can read a plurality of tag information within a radius of several meters ahead of the RFID reader. However, they cannot detect the position of the tag in applications that recognize only a tag at a specific position. In this study, we propose a new RFID system that can interrogate the tag of a specific location selectively by using the position information of the tag. This can be done by only adjusting the reader’s operating frequency. To verify the feasibility of the proposed system, we implemented a 2.4 GHz RFID reader whose frequency can be varied by using a phase-locked loop circuit and a backscattered tag. Experimental results confirm that the tag position can be sensed exactly.

A Compact Key-Shaped Antenna Design for Microwave Rfid Applications

A Compact Key-Shaped Antenna Design for Microwave Rfid Applications

Design and Simlation of a Dual-Band Microstrip Patch Antenna for microwave RFID Applications

Design and Simlation of a Dual-Band Microstrip Patch Antenna for microwave RFID Applications

Design of C-Band Microstrip Patch Antenna for Radar Applications Using IE3D

In the recent years the development in communication systems requires the development of low cost, minimal weight and low profile antennas that are capable of maintaining high performance over a wide spectrum of frequencies. This technological trend has focused much effort into the design of a microstrip patch antenna. The objective of this paper is to design an microstrip line fed rectangular microstrip patch antenna which operates in C-band at 5GHz. Therefore, method of moments based IE3D software is used to design a Microstrip Patch Antenna with enhanced gain and bandwidth. IE3D is an integrated full-wave electromagnetic simulation and optimization package for the analysis and design of 3D and planar microwave circuits, MMIC, RFIC, RFID, antennas, digital circuits and high speed Printed Circuit Board (PCB). The IE3D has become the most versatile, easy to use, efficient and accurate electromagnetic simulation tool. The length of the antenna is nearly half wavelength in the dielectric it is a very critical parameter, which governs the resonant frequency of the antenna. In view of design, selection of the patch width and length are the major parameters along with the feed line dimensions. Desired patch antenna design was simulated by IE3D simulator program. The entire project is being carried out at National Atmospheric Research Laboratory (NARL), ISRO.

Multitransmitter Wireless Power Transfer Optimization for Backscatter RFID Transponders

We present an efficient method for enhancing far-field wireless power transfer (WPT) to highly power-constrained mobile devices such as UHF and microwave RFID transponders using a multiple-input-multiple-output (MIMO) base station system. Existing techniques for channel estimation are prohibitively complex and consume too much power to be integrated into milliwatt- or microwatt-class wirelessly powered devices. We show that power transfer can be optimized using a transponder's backscatter signal alone, without requiring channel estimation and power measurement circuitry on the transponder. A measurement-based proof of concept is presented, illustrating that for any linear backscatter transponder, power optimization based on the backscattered signal is equivalent to local measurement at the mobile device itself. Using an 8 × 8 MIMO transceiver array to optimize power delivery across 100 randomly chosen locations in our office environment, we observe an average WPT enhancement of 8.1 dB relative to an unoptimized transmitter configuration. Transponders with nonlinear power harvesters can easily be supported with the addition of a single RF switching transistor.

Adaptive Array Antenna Using On-Off and CMA Algorithms for Microwave RFID Readers

This paper proposes an adaptive antenna using a combination of on-off and CMA algorithms. With the proposed technique, the on-off algorithm is first employed to search for a desired signal direction in which maximum received power is achieved. Then, interference is suppressed by performing CMA. Simulations are conducted according to the potential application of the proposed adaptive antenna. The simulation results show the SINR improvement implying that the proposed adaptive antenna can be applied to microwave RFID systems in order to resolve reader collision. Furthermore, the proposed adaptive antenna is implemented and then experimented. The experimental results verify that the proposed adaptive antenna can reduce interference resulting in the collision problem.

Slot Loaded Circular Microstrip Antenna with Meandered Slits

A novel compact dual-frequency microstrip antenna is achieved by embedding two parallel slots to the radiating edges and insetting slits at the non-radiating edges. The proposed antenna exhibits dual-frequency band behavior operating at 867 MHz and 2.45 GHz suitable for UHF and microwave RFID application. The slot loading effect has been studied and evaluated. The two desired frequencies are tunable with frequency ratio of 2.66 to 2.95 by varying the meandered slit length. A good agreement is obtained between the simulated results and experimental results.

A CMOS Bridge Rectifier for HF and Microwave RFID Systems

In this paper, a CMOS bridge rectifier for HF and microwave RFID systems is presented. The proposed RFID CMOS bridge rectifier is designed with two NMOSs and two PMOSs whose gates are connected to the antenna, and it is operated as a full wave bridge rectifier. The simulation results obtained with SPICE show the well rectified and high enough DC output voltages for the operating frequencies of 13.56 MHz, 915 MHz, and 2.45 GHz which are used in various RFID systems. The obtained DC output voltages are sufficiently high for driving the low power microchip in RFID transponder for the frequency range of HF and microwave.