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We present RFexpress! the first-ever system to recognize emotion from body movements and gestures via Device-Free Activity Recognition (DFAR). We focus on the distinction between neutral and agitated states in realistic environments. In particular, the system is able to detect risky driving behaviour in a vehicular setting as well as spotting angry conversations in an indoor environment. In case studies...
Flight inspection of radio-based terrestrial navigation systems is crucial for sufficient accuracy. Especially in proximity of wind turbines (WT), which have arisen in recent years due to government subsidies for renewable energies, flight inspections must be carried out. This causes problems that hinder the usage of conventional aircraft: Even rotorcraft (e.g. helicopters) require a certain amount...
This paper proposes a reconfigurable scheme of wireless power transmission in fully-enclosed box. The proposed scheme includes one transmitting element and multiple parasitic elements. Field distribution inside the box is reconfigured by switching the parasitic elements' termination between open and short, with the aim of delivering wireless power efficiently to a receiver whose location is not fixed...
This paper discusses the influence of non-idealities in the analog transmit and receive frontend of an MMIC-based 300 GHz wireless link on the receive signal quality. The degradation of EVM due to limited bandwidth and gain imbalance in the quadrature up- and down-converters is considered and compared to experimentally achieved data. Using adaptive equalization and quadrature error correction in the...
A new direct conversion and high speed uni-mode (QPSK) receiver designed with MMICs is proposed for 5.8 GHz ISM-band communications. The receiver architecture consists of one MMIC module for receiver front-end to include a six-port based circuit with matched RF detectors and low noise amplifiers (LNAs). A second module of receiver is designed with hybrid integrated circuits (HIC) and it performs all...
An antenna pattern measurement system has been developed which operates over the frequency range 1 to 12.4 GHz. The system makes pattern measurements and tests gain, beamwidths, and sidelobe levels under far-field conditions. Measurements using a Hewlett-Packard 8410A vector network analyzer as the receiver are managed by an in-house-developed software package for use on an IBM PC-AT microcomputer.
In today's world the most common wireless technology uses radio frequency(RF), Microwave, infrared(IR) for data communication. But ultrasonic can be a promising alternative method as unlike RF it does not have any biological effect that results in heating of human tissue. The development of aeronautical single channel and multichannel ultrasonic data communication system is discussed in this paper...
This work presents a bandpass sampling receiver architecture, which takes the advantages of low IF approach while implementing downconversion and image rejection with-out mixer or frequency varying oscillators. The RF signal is downcoverted to a low-IF by means of a quadrature bandpass sampling. A fixed and reduced sampling frequency is applied. The second quadrature downconversion to baseband is...
This paper presents at high speed and wideband direct receiver based on delta-sigma architecture. The effects of inter-symbol inference are discussed in this paper. In addition, a robust technique using a Decision Feedback Equalizer for multi-level (three bits) non-return-to-zero feedback Digital-to-Analog Converter in the receiver is also studied. This technique is proposed to reduce the dynamic...
Wake-up receivers (WuRXs) are low-power radios that continuously monitor the RF environment to wake up a higher-power radio upon detection of a predetermined RF signature. Prior-art WuRXs have 100s of kHz of bandwidth [1] with low signature-to-wake-up-signal latency to help synchronize communication amongst nominally asynchronous wireless devices. However, applications such as unattended ground sensors...
Digital receiver (RX) arrays featuring ADCs at each element enable massive multi-in-multi-out (MIMO) applications, but since spatial interference rejection is absent in the RF/analog domain, RF/analog/ADC dynamic range is challenged in an environment where strong and weak spatially distinct in-band signals co-exist. Recent MIMO RX array works [1,2] attempt to mitigate this problem with (single) spatial...
For true mobility, wearable electronics should be self-powered by the environment. On-body thermoelectric (∼50µW/cm2) is a maturing energy source but delivers a deeply low and inconstant output voltage (0.05 to 0.3V) hindering its utility. With the limited power efficiency of ultra-low-voltage (ULV) boost converters (64% in [1]), there is a rising interest in developing ULV radios that can operate...
LTE-advanced wireless receivers require high-linearity up-front filtering to prevent corruption of the in-band signals by strong out-of-band (OOB) signals and self-interference from the transmitter. SAW duplexer filters are generally used for this purpose, but supporting the plethora of existing and new bands becomes troublesome with separate filters for each band. In this paper we explore the possibility...
Ultra-narrow-band (UNB) signaling is an enabling technology for low-power wide-area (LPWA) networks for the “Internet-of-Things”. Indeed, UNB signaling, based on spectrally efficient modulations such as DBPSK, simultaneously optimizes network capacity while maximizing the communication link budget. However, UNB signaling poses many technical challenges. In the receiver, carrier frequency offsets (CFO)...
Magnetic Resonance Imaging (MRI) is a widely used medical imaging technique. It employs a strong static magnetic field (1.5 to 10.5T for human imaging) to split the spin states of the 1H nuclei in the body, and RF excitation to induce transitions and coherence among them. Gradient fields are superimposed to modulate the 1H resonance frequency, which enables spatially distinguishable signals to be...
A radar sensor for high speed moving objects is implemented using single chip CMOS UWB IC. To reduce the measuring and processing time for the fast moving target, the reliable and low power consumed envelope detection architecture is used at the expense of high resolution. The equivalent time sampling technique is adopted for UWB transceiver, employing delay locked loop and digitally synthesized impulse...
A combination 95 GHz radar and 270/560 GHz spectrometer is being built as a space instrument prototype for probing plumes and jet phenomena in the solar system. Dubbed GAISR (Gas And Ice Spectrometer/Radar), the instrument's radar will make simultaneous range/Doppler measurements of 0.1–10 mm sized ice and dust particles out to a few km in range, while its tunable spectrometer will detect the abundance...
Today's electronic warfare (EW) systems require fast electronic intelligence (ELINT) to measure frequency parameters of radars and to scan predefined frequency bands for possible target radar emissions. Target radar signals are usually strictly time limited events and ELINT systems should be able to catch these emissions and categorize the source radar according to its threat library in a very short...
Design and implementation of acquisition system using radio frequency (ASK) module with personal computer (PC) and microcontrollers (PIC) is proposed in this work. The paper includes hardware and software design. The first part of the system is composed of measurement instruments such as sensors, electric furnaces, pneumatic process and wireless transmitter (TX). The second part consists of radio...
This paper designs a Low Noise Amplifier (LNA) used in RF front end receiver system for wireless sensor network applications. The proposed LNA adopt post distortion technique. This Low Noise Amplifier provides a low noise figure of 2.14 dB with a forward gain of 16.6dB. The LNA circuit consumes a power of 11.6mW for 1.8V supply. The circuit is implemented using 180nm CMOS technology.
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