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Most of IoT applications include large number of distributed sensors which are interesting in specific geographical area. A large number of IoT entities have multiple relations and dynamic connections with each other. And there are many group communication requirements. Flexible multicast mechanism will be essential in such environments but it is difficult to satisfy verious requirements by means...
Backscatter communication enables a device to transmit or receive data using only the energy harvested from ambient RF signals. It can be realized via employing energy-efficient modulation and demodulation mechanisms. Specifically, a threshold-based demodulation method integrated with signal smoothing has generally been employed for backscatter communications. However, previous proposals considering...
As a step toward sustainable wireless sensing, we present a proof of concept system that uses a Plant Microbial Fuel Cells (PMFC) as a power source. To match the very low power production capabilities of the PMFC, we couple it with an ultra-low power wake-up receiver used as a trigger for sampling and transmission of the sensed value. We demonstrate that this combination, with a new, receiver initiated...
We describe an AlN-based resonant switch (resoswitch) for use in a Near-Zero (NZero) RF Wake-up receiver. A folded beam structure compensates for the curvature caused by the stress gradient in sputtered AlN and ensures that the free end of center actuation beam is level with the side anchor beams. A 80.13 kHz resoswitch with Q over 4000 and an actuation gap of approximately 600 nm turns on when a...
In multiple receivers wireless power transfer (WPT) systems, it is preferable to retune the resonant frequency of every receiver to the transmitter operating frequency in front of frequency mismatches. This paper discusses a proposal for electronic tuning for WPT receivers by means of a variable active switch-mode inductance. The proposed method benefits from the gyrator concept to emulate a variable...
This paper presents a time-interleaved pipelined-SAR converter targeting a multi-band mobile communication receiver. The input buffer is based on a super-source follower and linearized by selecting a specific bias current and drain bias resistor. Time interleaved sampling time mismatch is resolved by using a common sample and hold circuit, and gain mismatch is corrected by fine tuning respective subADC...
Reflection radio principles, used in RFID systems, have been recently exploited in wireless sensor networking, due to their inherent low-power requirements. This work offers a complete batteryless analog sensor design, implemented and tested in real-world conditions, able to backscatter its sensed information, without any type of analog-to-digital converter (ADC), digital logic or dedicated illuminator,...
Capacitive micromachined ultrasonic transducers (CMUTs) are prone to having low transmit sensitivity. According to large signal CMUT models, this shortcoming can be overcome with higher pulse voltages and optimized bipolar pulse drives [1]. Therefore, a supply-inverted bipolar pulser and a Tx/Rx switch are proposed to drive CMUTs in medical ultrasound imaging applications. These circuits are particularly...
This paper investigates a high power factor switch-based wireless power transfer front-end circuit for heterogeneous systems. This circuit uses an integrated switching rectifier, implemented in 0.18um 1.8V/5V CMOS process. An integrated pair of phase synchronizers is used to align the waveshape of a wirelessly-coupled sinusoidal voltage source in the receiving coil to the corresponding conducting...
This paper presents an off-body radio channel measurements in a ferry passenger cabin at 2.45 GHz band, for static sleeping scenarios with different body orientation and on-body antennas placements, and also for upper and lower sleeping berths. The measurements have been performed with two types of on-body wearable receiving antennas: FlexPIFA (flexible planar inverted F antenna), and FlexNotch (flexible...
This paper describes improvements in the Farrow structured variable fractional delay (FD) Lagrange interpolation. The main idea is to replace the first sub-filter of the Farrow structure by a sinc-interpolation filter of half a sample period to achieve a superior FD approximation in the vicinity of half a sample period. Its primary advantages over classical Farrow structured FD Lagrange interpolators...
The limitations of single-frequency wireless power transfer provide a strong incentive to use spread spectrum techniques. While techniques for transmitting power using spread spectrum modulation already exist, this paper introduces different receiver topologies and algorithms for receiving power spread across a wideband of frequencies. The power output and the efficiency of receivers is constrained...
The electromagnetic susceptibility of Radio-Frequency (RF) Front-Ends is studied. A RF receiver has nonlinear properties induced by its first stages (Switch, Low-Noise Amplifier and Power Amplifier). Two tones are injected in the RF system, with interference signal power ranging from low to high level. It creates inband intermodulation products (IM), which are partly reflected at the input and become...
This paper deals with the effects of an electromagnetic interference (EMI) from an out-of-band signal impinging on a 2.4 GHz RF receiver operating in the linear regime. The injection signal is radiated in the near-field above the circuit package at a frequency of 60 GHz. Due to the nonlinear behavior of active devices, we observed a gain quenching leading to a complete inhibition of the receiver that...
To meet yet higher speed and capacity demands, 5G will turn to mm-waves for more bandwidth. In this paper some receiver design issues occurring when moving from current 4G bands to mm-wave frequencies are discussed. The local oscillator phase noise increases by 6dB/octave with frequency and will ultimately limit spectrum efficiency. To analyze this, a phase noise model, based on a test chip designed...
In this paper, we consider optimal transceiver design and relay selection for simultaneous transfer of data and energy in a cooperative network consisting of amplify-and-forward (AF) relays. In this context, we address two different problems and propose optimal relay selection and transceiver processing. Furthermore, the problems are formulated for both time switching (TS) and power splitting (PS)...
An IEEE 802.11ah-compliant RF transceiver with a direct-conversion receiver and a fully-digital polar transmitter is presented. For the receiver, a current-mode RF front-end covers the mandatory modes worldwide from 755MHz to 928MHz. The digitally-assisted analog baseband achieves variable gains and bandwidths with an automatic gain/DC-offset calibration. Implemented in 40nm CMOS with 1V supply, this...
Wireless-powered chips are used in a wide range of applications, including biomedical implants. However, the resonant frequency of the power receiving circuit can be affected not only by process variations, but also by the changing environment. In order to optimize the power transfer and allow the chip to work despite these variations, a fully integrated tuning system is proposed. After having assessed...
A 4-bit 4Msps successive approximation (SAR) phase-domain analog-to-digital converter (Ph-ADC) for zero intermediate frequency (IF) Bluetooth low energy (BLE) receivers is proposed. With the SAR operation, the Ph-ADC requires only 52 current elements and 1 comparator, in contrast to the conventional design which needs 260 current elements and 8 comparators. Simulation results show that the digital...
The bandwidth of the RF amplifier severely limits the use of gain-boosted N-path receivers at high frequencies. Apart from limitation on the achievable impedance matching, the noise figure degradation severely handicaps the performance of the receiver. This paper describes a linear periodically time-variant (LPTV) analysis of the gain-boosted N-path receiver taking the amplifier bandwidth into consideration...
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