Band Pulse Research Articles

A Novel UWB RFID Tag Using Active Frequency Selective Surface

This work describes an actively controlled frequency selective surface (FSS) to implement ultrawideband radio identification (RFID) tags. The tag exploits the change in the radar cross section (RCS) of the FSS, which is loaded with switching PIN diodes to modulate the backscattered time-domain response of the tag to an input ultra-wide band pulse. The basic operation theory of the system is explained. An experimental setup based on a ultrawideband radar working as a reader is proposed to measure the modulated radar cross section of the tags. As a proof of concept, a battery-assisted or semipassive tag has been developed.

Pulse Switching: Toward a Packet-Less Protocol Paradigm for Event Sensing

This paper presents a novel pulse switching protocol framework for ultra light-weight wireless network applications. The key idea is to abstract a single Ultra Wide Band (UWB) pulse as the information switching granularity. Pulse switching is shown to be sufficient for on-off style event monitoring applications for which a monitored parameter can be modeled using a binary variable. Monitoring such events with conventional packet transport can be prohibitively energy-inefficient due to the communication, processing, and buffering overheads of the large number of bits within a packet's data, header, and preambles for synchronization. The paper presents a joint MAC-routing protocol architecture for pulse switching with a novel hop-angular event localization strategy. Through analytical modeling and simulation-based experiments it is shown that pulse switching can be an effective means for event networking, which can potentially replace the traditional packet transport when the information to be transported is binary in nature.

Optical characterization of inidividual liposome-loaded microbubbles

Newly developed liposome-loaded (LPS) microbubbles [1] were characterized by comparing their oscillating response with standard phospholipid-shelled (BARE) microbubbles using the ultra-high speed imaging camera (Brandaris 128). 73 LPS bubbles and 41 BARE bubbles of diameters ranging from 3 μm to 10 μm were insonified by narrow band pulses with a driving frequency ranging from 0.5 MHz to 4 MHz and an acoustic pressure from 5 kPa to 100 kPa. Shell elasticity of LPS bubbles (0.17±0.1 N/m) was nearly the same as that of BARE bubbles (0.19±0.1 N/m) for all investigated bubble sizes. Clear difference of shell viscosity was found for bubbles larger than 6 μm. Averaged viscosity of LPS bubbles (2.5×10-8 kg/s) was almost twice of that of BARE bubbles (1.4×10-8 kg/s). A second finding for LPS bubbles was the dominant “expansion-only” behavior (70% of LPS bubbles), while this was only 13% for BARE bubbles. Results from this study will facilitate future preclinical studies and clinical applications of LPS bubbles for ultrasound triggered drug delivery system. Reference 1. Geers, B., et al., J Control Release, 2011. 152(2): p. 249-56.

High voltage ultrawide band pulse generator using Blumlein pulse forming line

A high voltage ultrawide band pulse generation system has been developed to radiate intense and ultrawide band electric fields for the examination of effects of the electric fields on the operation of electronic devices. As major components of the system, a helical strip∕wire type of air-cored pulse transformer and a triaxial type of Blumlein pulse forming line have been designed and fabricated to amplify and shape the output pulse, respectively. For the construction of a compact system, the pulse transformer and the Blumlein line are installed in a single cylindrical container. An ultrawide band TEM horn antenna has been fabricated to radiate the Blumlein output pulses to electronic devices. A number of experimental results demonstrate that the system is capable of providing an output pulse whose voltage is greater than 300 kV, pulse duration is ~5 ns, and rise time is ~500 ps with repetition rate of 10 Hz. The peak-to-peak value of electric field intensity of a radiated pulse is also measured to be approximately 42 kV/m at a distance of 10 m away from the antenna.

Numerical simulation of the amplification of picosecond laser pulses in tapered semiconductor amplifiers and comparison with experimental results

We apply a traveling wave model to the simulation of the amplification of laser pulses generated by Q-switched or mode-locked distributed-Bragg reflector lasers. The power amplifier monolithically integrates a ridge-waveguide section acting as pre-amplifier and a flared gain-region amplifier. The diffraction limited and spectral-narrow band pulses injected in to the pre-amplifier have durations between 10ps and 100ps and a peak power of typical 1W. After the amplifier, the pulses reach a peak power of several tens of Watts preserving the spatial, spectral and temporal properties of the input pulse. We report results obtained by a numerical solution of the traveling-wave equations and compare them with experimental investigations. The peak powers obtained experimentally are in good agreement with the theoretical predictions. The performance of the power amplifier is evaluated by considering the dependence of the pulse energy as a function of different device and material parameters.

Experimental Results on UWB Pulse Propagation in Low-Voltage Power Cables With Different Cross Sections

The paper presents some experimental results on unusual propagation of an ultrawide band (UWB) pulse in low-voltage three-conductor power cables. For cables of flat cross section, the results confirm the possibility of modal decomposition of the pulse into two low level pulses. However, this phenomenon does not occur in cables of circular cross section.

Upconversion of Gain-Switched Laser Pulses for Optical Generation of UWB Signals

We propose and experimentally demonstrate a simple, low-cost optical ultra-wide band (UWB) pulse generation method. A gain-switched laser pulse is dispersed by optical fiber propagation and upconverted to the center of the US Federal Communications Commission (FCC) mask using an optical intensity modulator. The generated UWB pulses comply with the FCC mask with relatively high power efficiencies. We also show that the optical fiber can be replaced with a fiber Bragg grating filter to make the transmitter compact. Wireless propagation of the UWB impulses is investigated by offline signal processing. A linear receiver and an energy detector are implemented. The linear filter shows a better BER performance, particularly in worse channel conditions. We reach the FEC limit of 10-3 after 3.5 m of wireless propagation at 856 Mb/s.

Acoustic Thickness Measurements Using Gas As A Coupling Medium

An acoustic apparatus adapted to operate in a gas filled space for making a non-contact thickness measurement of an object to be measured or for making a non-contact characterisation of a medium located on the opposite side of the object. The apparatus comprises an electro acoustic transceiver to output an acoustic signal towards the object to be measured and receive an acoustic response signal, and a signal processor to process the response signal and to determine the thickness of the object. The transducer has a transducer-to-gas acoustic interface, and is adapted to emit an acoustic broad band pulse towards the object and to receive an acoustic resonance response signal. The signal processor determines the thickness of the object to be measured or makes a characterisation of a medium located on the opposite side of the object using a fast Fourier transformation (FFT) of the resonance response signal above a predetermined signal to noise level.

Nonlinear shear wave interaction at a frictional interface: Energy dissipation and generation of harmonics

Analytical and numerical modeling of the nonlinear interaction of shear wave with a frictional interface is presented. The system studied is composed of two homogeneous and isotropic elastic solids, brought into frictional contact by remote normal compression. A shear wave, either time harmonic or a narrow band pulse, is incident normal to the interface and propagates through the contact. Two friction laws are considered and the influence on interface behavior is investigated: Coulomb’s law with a constant friction coefficient and a slip-weakening friction law which involves static and dynamic friction coefficients. The relationship between the nonlinear harmonics and the dissipated energy, and the dependence on the contact dynamics (friction law, sliding, and tangential stress) and on the normal contact stress are examined in detail. The analytical and numerical results indicate universal type laws for the amplitude of the higher harmonics and for the dissipated energy, properly non-dimensionalized in terms of the pre-stress, the friction coefficient and the incident amplitude. The results suggest that measurements of higher harmonics can be used to quantify friction and dissipation effects of a sliding interface.

Demonstration of negative signal delay with short-duration transient pulse

This paper introduces theoretic and experimental analyses of short-duration pulse propagation through a negative group delay (NGD) circuit. The basic analysis method of this electronic circuit operating in baseband and microwave frequencies is investigated. Then, its electrical fundamental characteristics vis-a-vis transient signals are developed. To validate the theoretic concept, planar hybrid devices with one- and two-stage NGD cells were designed, simulated, fabricated and tested. Transient analyses with ultra-wide band (UWB) pulse signals with different widths are realized. Then, experimental results in good agreement with the theoretical predictions were observed. Consequently, group delay going down under −2.5 ns is evidenced in baseband frequency up to 63 MHz with one-stage NGD cell. In time-domain, a Gaussian pulse in advance of about t 0 = −1.5 ns or 20% of its half-height time-width was measured. This corresponds to a negative group velocity of about v g = L / t 0 = −0.13 c ( L is the physical length of the tested device and c is light speed in the vacuum). More significant NGD value over 100-MHz bandwidth is stated with two-stage NGD cells. This results in a Gaussian pulse peak advance of about −5 ns (raising a group velocity of about v g = −0.12 c ) or 31% of its half-height time-width. Finally, some potential applications based on the NGD function are discussed.

Contrast imaging by non-overlapping dual frequency band transmit pulse complexes

SURF contrast imaging, as described previously in the literature, is a contrast agent detection technique achieved by processing of the received signals from transmitted dual frequency band pulse complexes with overlapping high-frequency (HF) and low-frequency (LF) pulses. The transmitted HF pulses are used for image reconstruction, whereas the transmitted LF pulses are used to manipulate the scattering properties of the contrast agent. As with harmonic contrast agent detection techniques, nonlinear wave propagation will, in most situations, also limit the specificity with the SURF contrast technique when transmitting overlapping HF and LF pulses. The present paper proposes an alternative SURF contrast imaging technique using transmit dual frequency band pulse complexes with non-overlapping HF and LF pulses. If the frequency of the LF manipulation pulse is close to the bubble resonance frequency, numerical simulations indicate a significant ring-down effect of the LF bubble radius response. Utilizing this bubble ring-down effect and transmitting the HF pulse just after the LF pulse, a contrast agent specificity approaching infinity accompanied by a contrast agent sensitivity only for contrast bubbles having resonance frequencies within a narrow frequency range may be obtained.

Nonlinear propagation delay and pulse distortion resulting from dual frequency band transmit pulse complexes

A method of acoustic imaging is discussed that potentially can improve the diagnostic capabilities of medical ultrasound. The method, given the name second order ultrasound field imaging, is achieved by the processing of the received signals from transmitted dual frequency band pulse complexes with at least partly overlapping high frequency (HF) and low frequency (LF) pulses. The transmitted HF pulses are used for image reconstruction whereas the transmitted LF pulses are used to manipulate the elastic properties of the medium observed by the HF imaging pulses. In the present paper, nonlinear propagation effects observed by a HF imaging pulse due to the presence of a LF manipulation pulse is discussed. When using dual frequency band transmit pulse complexes with a large separation in center frequency (e.g., 1:10), these nonlinear propagation effects are manifested as a nonlinear HF propagation delay and a HF pulse distortion different from conventional harmonic distortion. In addition, with different transmit foci for the HF and LF pulses, nonlinear aberration will occur.

Model identification of EMP electromagnetic coupling using Volterra kernel

Electromagnetic pulses (EMP) are capable of causing effects like malfunctions, performance degradation, interferences, and destructions in electronic and electrical systems. The EMP effect simulation is one of key points from home and abroad. Furthermore, EMP coupling is the promise and foundation of effect evolution and protection. In this paper, a new method, based on the combination of system identification theory and Volterra series algorithm, was proposed for the analysis of the EMP electromagnetic coupling phenomena from an external field to an inner electric system. In particular, we focused on the ultra wide band (UWB) pulses, which were able to cause malfunctions or even destructions of complex electronic systems and the coupling effect has not yet been sufficiently analysed. Based on experience data, we designed a new method using Volterra series to identify EMP electromagnetic coupling model. We firstly analysed the theory foundation of non-parameters model evolution. And then, to verify the validity of this method, we designed UWB pulses electromagnetic coupling table and gained radiation coupling data. Finally, model testing results showed that the increased model accuracy and smaller computation will improve EMP effect evolution, also which can apply this method to EMP electromagnetic coupling model identification.

Multi-Static UWB Radar Approach Based on Aperture Synthesis of Double Scattered Waves for Shadow Region Imaging

SUMMARY The applicability in harsh optical environments, such as dark smog, or strong backlight of ultra-wide band (UWB) pulse radar has a definite advantage over optical ranging techniques. We have already proposed the extended Synthetic Aperture Radar (SAR) algorithm employing double scattered waves, which aimed at enhancing the reconstructible region of the target boundary including shadow region. However, it still suffers from the shadow area for the target that has a sharp inclination or deep concave boundary, because it assumes a mono-static model, whose real aperture size is, in general, small. To resolve this issue, this study proposes an extension algorithm of the double scattered SAR based on a multi-static configuration. While this extension is quite simple, the effectiveness of the proposed method is nontrivial with regard to the expansion of the imaging range. The results from numerical simulations verify that our method significantly enhances the visible range of the target surfaces without ap riori knowledge of the target shapes or any preliminary observation of its surroundings.

Acceleration for Shadow Region Imaging Algorithm with Multiple Scattered Waves for UWB Radars

Ultra-wide band (UWB) pulse radar has high range resolution, and is thus applicable to imaging sensors for a household robot. To enhance the imaging region of UWB radar, especially for multiple objects with complex shapes, an imaging algorithm based on aperture synthesis for multiple scattered waves has been proposed. However, this algorithm has difficulty realizing in real-time processing because its computation time is long. To overcome this difficulty, this letter proposes a fast accurate algorithm for shadow region imaging by incorporating the Range Points Migration (RPM) algorithm. The results of the numerical simulation show that, while the proposed algorithm affects the performance of the shadow region imaging slightly, it does not cause significant accuracy degradation and significantly decreases the computation time by a factor of 100 compared to the conventional algorithm.

一种用于低重复频率窄脉冲的脉冲稳偏技术

一种用于低重复频率窄脉冲的脉冲稳偏技术

Micropower Impulse Radar: A Novel Technology for Rapid, Real-Time Detection of Pneumothorax

Pneumothorax detection in emergency situations must be rapid and at the point of care. Current standards for detection of a pneumothorax are supine chest X-rays, ultrasound, and CT scans. Unfortunately these tools and the personnel necessary for their facile utilization may not be readily available in acute circumstances, particularly those which occur in the pre-hospital setting. The decision to treat therefore, is often made without adequate information. In this report, we describe a novel hand-held device that utilizes Micropower Impulse Radar to reliably detect the presence of a pneumothorax. The technology employs ultra wide band pulses over a frequency range of 500 MHz to 6 GHz and a proprietary algorithm analyzes return echoes to determine if a pneumothorax is present with no user interpretation required. The device has been evaluated in both trauma and surgical environments with sensitivity of 93% and specificity of 85%. It is has the CE Mark and is available for sale in Europe. Post market studies are planned starting in May of 2011. Clinical studies to support the FDA submission will be completed in the first quarter of 2012.

一种用于低重复频率窄脉冲的脉冲稳偏技术

一种用于低重复频率窄脉冲的脉冲稳偏技术

一种用于低重复频率窄脉冲的脉冲稳偏技术

一种用于低重复频率窄脉冲的脉冲稳偏技术

Application of transient pulses on power supply cables by using commercial of the shelf components

Abstract. This paper deals with the development of ultra wide band pulse devices using merchantable hardware. The major goal is to create wide band transients and pulses with simple electronic equipment and to achieve high voltages and low pulse rise times. The propagation of these signals on common power lines are examined to analyse and forecast the effects on attached devices.