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This brief presents a pulse phase modulation scheme for simultaneous wireless power and downlink data transfer system through the same inductive link. It is proved that the impact of data transfer on power transfer can be minimized when using the proposed pulse phase modulation. A prototype is built up with 1-MHz resonant frequency for power transfer. It shows that the data can be successfully transferred while achieving a data rate of 125 kb/s, which is 1/8 of carrier frequency, and a bit error rate (BER) of $4.5\boldsymbol {\times } 10^{\boldsymbol {-6}}$. Furthermore, compared with the case without data transfer, the input powers and the output powers are almost unchanged, respectively. [ABSTRACT FROM AUTHOR]

This paper presents a novel maximum efficiency point (MEP) tracking method for wireless power transfer (WPT) systems. It is proved that at the MEP for a typical system containing a boost converter on the receiving end, the derivative dD/dV{\text{in}} ( V{\text{in}} being the inverter's dc input and D being the duty cycle of the converter) is equal to or smaller than a constant \beta that is determined by system parameters. By tuning V\textin and comparing dD/dV\textin with \beta , the MEP can be tracked without a power or current sensor, hence reducing the tracking cost. A WPT system is demonstrated experimentally to verify the method. When the diameters of and the vertical distance between the transmitting and receiving coils are 4.3 and 2.35 cm, respectively, without horizontal misalignment, high efficiency is maintained even when the load ranges from 5 to 100 Ω, and the efficiency improvement reaches 41.2% when compared to the measured efficiencies without the proposed method. The differences between the maximum efficiencies tracked by the proposed method and the manually searched maximum values are at most 1.8%. Extension of the proposed method to WPT systems employing other popular forms of inverter, dc/dc converter, and coil topology is also presented. [ABSTRACT FROM AUTHOR]

A dominant-pole substitution (DPS) technique for low-dropout regulator (LDO) is proposed in this paper. The DPS technique involves signal-current feedforward and amplification such that an ultralow-frequency zero is generated to cancel the dominant pole of LDO, while a higher frequency pole substitutes in and becomes the new dominant pole. With DPS, the loop bandwidth of the proposed LDO can be significantly extended, while a standard value and large output capacitor for transient purpose can still be used. The resultant LDO benefits from both the fast response time due to the wide loop bandwidth and the large charge reservoir from the output capacitor to achieve the significant enhancement in the dynamic performances. Implemented with a commercial 0.18-μm CMOS technology, the proposed LDO with DPS is validated to be capable of delivering 100 mA at 1.0-V output from a 1.2-V supply, with current efficiency of 99.86%. Experimental results also show that the error voltage at the output undergoing 100 mA of load transient in 10-ns edge time is about 25 mV. Line transient responses reveal that no more than 20-mV instantaneous changes at the output when the supply voltage swings between 1.2 and 1.8 V in 100 ns. The power-supply rejection ratio at 3 MHz is −47 dB. [ABSTRACT FROM AUTHOR]

Intrabody communication has been of great research interest in recent years. This paper proposes a novel, compact but accurate body transmission channel model based on RC distribution networks and transmission line theory. The comparison between simulation and measurement results indicates that the proposed approach accurately models the body channel characteristics. In addition, the impedance-matching networks at the transmitter output and the receiver input further maximize the power transferred to the receiver, relax the receiver complexity, and increase the transmission performance. Based on the simulation results, the power gain can be increased by up to 16 dB after matching. A binary phase-shift keying modulation scheme is also used to evaluate the bit-error-rate improvement. [ABSTRACT FROM AUTHOR]

Efficiently answering XML keyword queries has attracted much research effort in the last decade. The key factors resulting in the inefficiency of existing methods are the common-ancestor-repetition (CAR) and visiting-useless-nodes (VUN) problems. To address the CAR problem, we propose a generic top-down processing strategy to answer a given keyword query w.r.t. LCA/SLCA/ELCA semantics. By “top-down”, we mean that we visit all common ancestor (CA) nodes in a depth-first, left-to-right order; by “generic”, we mean that our method is independent of the query semantics. To address the VUN problem, we propose to use child nodes, rather than descendant nodes to test the satisfiability of a node $v$ w.r.t. the given semantics. We propose two algorithms that are based on either traditional inverted lists or our newly proposed LLists to improve the overall performance. We further propose several algorithms that are based on hash search to simplify the operation of finding CA nodes from all involved LLists. The experimental results verify the benefits of our methods according to various evaluation metrics. [ABSTRACT FROM PUBLISHER]

This paper presents a low power, long-transmission distance, high data rate intrabody communication (IBC) analog receiver front end (RFE). First, to optimize the transmission performance, conventional transmission line analysis scheme is creatively adopted to the IBC design to characterize the body channel. Second, switched-capacitor filters based on sampling rate boosting technique are adopted for higher accuracy and lower power consumption. Third, a novel RFE topology is proposed to further enhance the IBC performance. The new RFE is designed and fabricated in a standard 180-nm CMOS process. Measurement results show that the RFE can successfully transmit data spanning the whole human body, around 180 cm, which is one of the longest transmission distances reported in related literatures. Furthermore, it reaches a maximum data rate of 2.5 Mb/s with a bit error rate less than 1e-7 and consumes 5.4 mW from a 1.8 V supply. The proposed RFE compares favorably to similar reported works. [ABSTRACT FROM AUTHOR]