Hong Kong Randnter for Logistics and Supply Chain Management Enabling Technologies

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Xi J.,Hong Kong Randnter for Logistics and Supply Chain Management Enabling Technologies
APCAP 2016 - 2016 IEEE 5th Asia-Pacific Conference on Antennas and Propagation, Conference Proceedings | Year: 2016

When RFID tags are embedded directly inside the package, the antenna can utilize the full dimension of the package and exploit greater design freedom to achieve better performance than traditional halfwave dipole. This paper proposes a low-cost high-directivity tag antenna, which takes the form of dipole longer than one wavelength and adopts a modified T-match network. Measurement and simulation results demonstrate that the proposed tag achieves a directivity about 5.0 dBi. © 2016 IEEE.


Liu S.,Peking University | Wang X.,Peking University | Shen J.,Peking University | Wang B.,Peking University | And 2 more authors.
Science China Information Sciences | Year: 2012

A novel direct conversion receiver with low cost and low power is implemented in a 0. 18 μm 1P6M standard CMOS process for a Mobile UHF RFID reader. A highly linear active mixer with low flicker noise and low noise active load is proposed. An efficient and low cost on-chip DC offset voltage canceling scheme is adopted with a high-input-impedance four-input OPAMP to buffer the output of the DC offset canceller (DCOC) block. The receiver has a measured input 1 dB compression point of -2 dBm and a sensitivity of -72 dBm in the presence of the large leakage signal from the transmitter. Only occupying a silicon area of 2. 5 mm 2 and consuming 21 mA from a 1. 8 V supply, the receiver makes the mobile UHF RFID reader to communicate with a transponder in a distance of 1 m conveniently. © 2012 Science China Press and Springer-Verlag Berlin Heidelberg.


Liu S.,Peking University | Wang B.,Peking University | Shen J.,Peking University | Wang X.,Peking University | And 2 more authors.
IET Conference Publications | Year: 2012

For a Mobile UHF RFID reader a fully integrated transceiver, which satisfies the protocols of EPC Class-1 Gen-2, is implemented in a 0.18um 1P6M standard CMOS process. In the receiver, to deal with the large leakage signal, a mixer utilizing BJT paralleling with NMOS as input stage and vertical NPN BJT as switching stage is proposed to achieve high linearity(-2dBm P1dB) and low 1/f noise. Furthermore, an efficient low cost on-chip DC offset canceller (DCOC) with a high-input-impedance four-input OPAMP is utilized. In transmitter, a sigma-delta DAC with a novel single to differential (S2D) is used to reduce the noise of the transmitter. Besides a linear up-conversion mixer and a power amplifier driver are proposed. The transmitter achieves an ACPR1 of -27dBc and ACPR2 of -51.8dBc. Supporting FM0, Miller2/4/8 demodulation and DSB-ASK modulation, occupying an area of 10.24mm2 and consuming 130mA from a 1.8V supply, the transceiver can communicate with a transponder in a distance of 1m.


Liu S.,Peking University | Wang X.A.,Peking University | Shen J.P.,Peking University | Wang B.,Peking University | And 2 more authors.
Science China Information Sciences | Year: 2014

A novel CMOS transmitter with low TX noise and high linearity is implemented in a 0.18 μm 1P6M standard CMOS process for Mobile UHF RFID reader. Adopting double-sideband amplitude-shift-keying (DSB-ASK) as the only modulation is supported, this transmitter has very low power consumption. A novel analog baseband circuit is proposed to reduce the transmitter noise. With a G″m-cancellation technology, a highly linear up-conversion active mixer and a power amplifier driver are designed. The transmitter has a measured output 1 dB compression point of 13.4 dBm. Occupying a silicon area of about 1 mm2 and consuming 144 mW from a 1.8 V voltage supply, the transmitter makes the Mobile UHF RFID reader communicate with a transponder in a distance of 1 m conveniently. © 2014 Science China Press and Springer-Verlag Berlin Heidelberg.


Ma Z.L.,University of Hong Kong | Jiang L.J.,University of Hong Kong | Xi J.,Hong Kong Randnter for Logistics and Supply Chain Management Enabling Technologies | Ye T.T.,Hong Kong Randnter for Logistics and Supply Chain Management Enabling Technologies
IEEE Antennas and Wireless Propagation Letters | Year: 2012

This letter presents a novel dual-band (HF and UHF) radio frequency identification (RFID) tag antenna. Two key challenges are faced: the compact dimension and the impaired bandwidth due to the couplings between two band structures. To enable the implementation of whole design on a credit-card-size single-layer support, a spiral coil along the edges of the card is designed to handle the HF (13.56 MHz) near-field coupling, and the UHF antenna is placed inside the coil instead of outside. Meanwhile, a diagonal symmetric design consisting of two meander lines inside the spiral coil is adopted for UHF band. This structure supports multiple resonance modes around 915 MHz to broaden the working bandwidth under the large inductive circumstance from the HF coil. The proposed antenna is easy for adjustment with ways of handling both coarse tuning and fine-tuning. Its overall dimension is of a credit card size on a single-layer thin substrate. The design methodology and antenna measurement results are both presented and discussed in the letter. © 2002-2011 IEEE.


Yang P.H.,University of Electronic Science and Technology of China | Li Y.,University of Hong Kong | Jiang L.,University of Hong Kong | Chew W.C.,University of Hong Kong | Ye T.T.,Hong Kong Randnter for Logistics and Supply Chain Management Enabling Technologies
IEEE Transactions on Antennas and Propagation | Year: 2011

Several compact, low profile and metal-attachable RFID tag antennas with a loop-fed method are proposed for UHF RFID systems. The structure of the proposed antennas comprise of two parts: (1) The radiator part consists of two shorted patches, which can be treated as two quarter-wave patch antennas or a cavity. (2) A small loop printed on the paper serves as the feeding structure. The small loop provides the needed inductance for the tag and is connected to the RFID chip. The input impedance of the antenna can be easily adjusted by changing loop dimensions. The antenna has the compact size of 80 mm × 25 mm × 3.5 mm, and the realized gain about -3.6 dB. The measured results show that these antennas have good performance when attached onto metallic surfaces. © 2011 IEEE.


Li Y.,University of Electronic Science and Technology of China | Li Y.,University of Hong Kong | Sun S.,University of Hong Kong | Jiang L.,University of Hong Kong | Ye T.T.,Hong Kong Randnter for Logistics and Supply Chain Management Enabling Technologies
IEEE Antennas and Propagation Society, AP-S International Symposium (Digest) | Year: 2012

In this paper, a compact hybrid-integrated microstrip rectangular ring antenna with circular polarization is proposed for RFID reader. By integrating a cross-slotted patch hybrid with a rectangular ring antenna in the same plane, the proposed antenna has the features of circular polarization, compact size, low cost, light weight and unique flexibility for RFID applications. A prototype operating at 915 MHz is designed and fabricated. The measured results agree well with the simulated results. © 2012 IEEE.


Mak C.-L.,Hong Kong Randnter for Logistics and Supply Chain Management Enabling Technologies | Hon M.A.,Hong Kong Applied Science and Technology Research Institute | Lau W.-M.,Hong Kong Applied Science and Technology Research Institute | Cheung W.-M.,Hong Kong Randnter for Logistics and Supply Chain Management Enabling Technologies
IPIN 2014 - 2014 International Conference on Indoor Positioning and Indoor Navigation | Year: 2014

In this paper, we introduce a novel method of using a single Wi-Fi fingerprinting technique to provide coarse position estimation and finer proximity location identification simultaneously without employing any additional tags and beacons. This method requires a special designed antenna together with a subtractive location referencing software algorithm. The method uniquely applies antenna null characteristics to replace the traditional tags-beacons approach for proximity identification. The fine proximity location identified by this method operates in a seamless manner from the user end, and it requires no additional hardware besides the smart device. This method of fine proximity location identification can be deployed in indoor or outdoor environment to work with the required infrastructure. A US and China patents of such novel technique have been filed in March 2014. © 2014 IEEE.


Xi J.,Hong Kong Randnter for Logistics and Supply Chain Management Enabling Technologies | Zhu H.,Hong Kong Randnter for Logistics and Supply Chain Management Enabling Technologies
2015 IEEE International Conference on RFID, RFID 2015 | Year: 2015

Impedance matching is a constant topic in the RFID community. However, it still heavily depends on the trial-and-error approach, even for the popular T-match. In this paper, the dynamics behind the impedance matching of T-match-dipole tags are studied systematically. Based on the inductance-based model stemmed from the transmission line model, the bandwidth characteristics of diverse matching scenarios are discussed. Closed-form expressions of the maximum bandwidths and the relevant conditions are provided. In particular, a special doubletuning scenario called the degenerated double-tuning is explored for the first time. Guided by the conditions of the maximum bandwidths, efficient design approaches are proposed for the embedded T-match dipole. Results of multiple design examples demonstrate the usefulness of the impedance matching theory and the design approaches presented. © 2015 IEEE.


Mak C.-L.,Hong Kong Randnter for Logistics and Supply Chain Management Enabling Technologies | Xi J.,Hong Kong Randnter for Logistics and Supply Chain Management Enabling Technologies
2016 IEEE International Conference on RFID, RFID 2016 | Year: 2016

The paper describes a novel passive tag design for RFID applications. The passive tag antenna has two separable parts, which are the feeding loop and the radiating element implemented at two different layers. Energy is efficiently coupled between these two parts when they overlap within designated positions. For demonstration purpose, the overall tag design is realized on a card (credit card size), and a card-holder, with the feeding loop embedded in the card and with the radiating element embedded in the card-holder. The key features of the tag design are i) the intended short read range of millimeter-to centimeter-level when the card is stand alone, and ii) the regular long read range of meter-level when the card is coupled with the card holder. With this distinctive characteristic, a card with a unique tag ID can be issued to a single person, on a one-to-one basis, for different read range access requirements in different situations, e.g. office gate access vs car park gate access of a single person to go in and out of a premises using the same access card, nearfield payment vs road toll payment using the same payment card. Therefore, unnecessary false-read can be minimized and no multiple cards (different tag IDs), with different read ranges, are needed for the same person. A PCT patent of such design has been filed in Sept 2015 for licensing. A few hundred of proof-of-concept prototypes have been fabricated recently for field trials. © 2016 IEEE.

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