In general, Micropower Impulse Radar (MIR) depends on Ultra-Wideband (UWB) transmission systems. UWB technology can supply innovative new systems and products that have an obvious value for radar and communications uses. Important applications include bridge-deck inspection systems, ground penetrating radar, mine detection, and precise distance resolution for such things as liquid level measurement. Most of these UWB inspection and measurement methods have some unique qualities, which need to be pursued. Therefore, in considering changes to Part 15 the FCC needs to take into account the unique features of UWB technology. MIR is applicable to two general types of UWB systems: radar systems and communications systems. Currently LLNL and its licensees are focusing on radar or radar type systems. LLNL is evaluating MIR for specialized communication systems. MIR is a relatively low power technology. Therefore, MIR systems seem to have a low potential for causing harmful interference to other users of the spectrum since the transmitted signal is spread over a wide bandwidth, which results in a relatively low spectral power density.

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Response to FCC 98-208 notice of inquiry in the matter of revision of part 15 of the commission's rules regarding ultra-wideband transmission systems

Reactive matching is extended to wide bandwidths using the impedance property of LC-ladder filters. In this paper, we present a systematic method to design wideband low-noise amplifiers. An SiGe amplifier with on-chip matching network spanning 3-10 GHz delivers 21-dB peak gain, 2.5-dB noise figure, and -1-dBm input IP3 at 5 GHz, with a 10-mA bias current.

A 3-10-Ghz low-noise amplifier with wideband LC-ladder matching network

Condition assessment of the buried utility service infrastructure

The use of large-size antenna arrays to implement pencil-beam forming techniques is becoming a key asset to cope with the very high throughput density requirements and high path-loss of future millimeter-wave (mm-wave) gigabit-wireless applications. Suboptimal beamforming (BF) strategies based on search over discrete set of beams (steering vectors) are proposed and implemented in present standards and applications. The potential of fully adaptive advanced BF strategies that will become possible in the future, thanks to the availability of accurate localization and powerful distributed computing, is evaluated in this paper through system simulation. After validation and calibration against mm-wave directional indoor channel measurements, a 3-D ray tracing model is used as a propagation-prediction engine to evaluate performance in a number of simple, reference cases. Ray tracing itself, however, is proposed and evaluated as a real-time prediction tool to assist future BF techniques.

Ray-Tracing-Based mm-Wave Beamforming Assessment

Electrical measurement is a simple innocuous tool for material characterization. Unlike for instance milk or dairy products, the majority of naturally grown food is composed of cells. The cells of meat or vegetables are surrounded by an insulating membrane, while the cytosol and the extracellular fluids are electrolytes. Despite the high permittivity of water, electrolytes behave like ohmic resistors up to hundreds of MHz. In contrast, membranes form capacitive elements due to their high resistance. The typical time constant for charging cell membranes is of the order of a microsecond. Thus, cells influence the impedance in a frequency range up to several MHz. At higher frequencies, the cytosolic content, i.e., macromolecules, gives rise to characteristic relaxation processes. Using the impedance in the microwave range where water dipoles show a distinct dispersion, humidity of dried matter can be addressed. Moreover, with sensitive measurement setup and proper models, one can determine the dry content in mashes and slurries as well. Several quality standards correlate well with the permeability of the membranes or the total water content. Because of the comparatively simple measurement of the electrical impedance together with advanced mathematical modeling, it is often a good approach in quality assessment of agricultural products. The change in conductivity of a culture medium contains information about the metabolism of incubated cells. Using specific culture media and time-lapse conductivity monitoring allows a high sensitivity and selectivity in microbial detection. Because the electrical impedance is very sensitive to the permeability of cell membranes, it is a great choice for the assessment of changes due to high voltage application. Today, many attempts to use impedance measurement in food technology show fast success in research but fail in practice. The reason is often an overestimation especially of the selectivity while underestimating the uncertainties in a harsh environment of a food-processing plant. Established, however, is the use of robust process measurement systems and the limitation of impedance measurement to applications with highly significant outcome or as supplemental measurement in a multiparameter approach. This review introduces the basics of bioimpedance measurement, points to sources of uncertainty, and presents successful applications in food industry.

Bioimpedance: A Review for Food Processing

The vitality of a human being is closely connected to temporal variations of its body geometry. This is quite obvious in the case of walking. But also when resting, the motion of inner organs such as lung or heart causes geometric alterations which may be registered by high-resolution ultra-wideband radar. Since the radio waves radiated by such radars are absolutely harmless, they may be deployed for monitoring of resident activities helping to ensure health, safety, and well-being of aged or needy people. These waves may also penetrate most of building materials and snow which makes them useful to detect earthquake and avalanche survivors, too. The most challenging task is the registration of respiration activity of an unconscious person. The principle of breathing motion detection by radar is explained and the major handicaps as well as appropriate counter measures are discussed. The possible structure of a survivor and residential injury detection radar system is considered and some results from field trials are summarized.

Remote vital sign detection for rescue, security, and medical care by ultra-wideband pseudo-noise radar

Ultra-wideband (UWB) sensing is an upcoming technique to gather data from complex scenarios such as nature, industrial facilities, public or private environments, for medical applications, non-destructive testing and many more. Currently it is hard to estimate the full spread of future applications. The measurement approach traditionally used is based on stimulation of the test objects by either short sub-nanosecond impulses or sine waves which are stepped/swept over a wide spectral band. This paper deals with an alternative approach, which uses very wideband pseudo-noise binary signals such as M-sequences for example. Such devices have a very high time stability, enable high measurement speed and do not burden the test objects with high voltage peaks. Furthermore, the device concept promotes monolithic circuit integration in a low cost semi-conductor technology. In what follows, the basic device concept and some extensions will be considered as well as some selected applications will be discussed.

Recent Advances and Applications of M-Sequence based Ultra-Wideband Sensors

The use of ultra-wideband signals for moisture sensing by electromagnetic wave interaction provides more information on the material under test compared to single tone or narrowband approaches, regarding spatial and frequency dependent phenomena. Current activities to regulate the emission of electromagnetic waves in the spectral band up to 10 GHz for sensor applications open new perspectives for microwave moisture sensing. Therefore, improved and cost effective ultra-wideband measurement principles will become more and more interesting. The use of short pulses or swept sine waves are classic approaches to cover a large spectral band. However, this paper deals with some variants of an alternative method, which applies pseudo-random codes, namely M-sequences, to stimulate the test objects. The method permits monolithic integration of the RF-electronics in SiGe technology. The signal generation and data capturing are referred to a common stable single tone clock and they are controlled by steep trigger signals. This provides for very stable operation, which allows for measurements in both time and frequency domain. Two versions of an M-sequence approach will be considered and their functioning will be demonstrated by means of simple measurement examples.

Liquid and moisture sensing by ultra-wideband pseudo-noise sequence signals

Ultra wideband sounding has been found to be suitable for a large number of applications in various areas. This results in a variety of different requirements concerning the measurement electronics. The article describes a conception of a measurement system, which provides for high flexibility in adapting performance to the actual need.

Ultra wideband radar assembly kit

This paper introduces an ultrawideband (UWB) channel sounding system. Its novel architecture allows real-time measurements of multiple time-variant radio propagation channels in different ultrawide frequency bands. Its architecture allows emulation of multiuser systems, sensor networks, localization systems, and distributed MIMO radar systems. The sounder uses a maximum length binary sequence (MLBS) excitation signal and correlation processing in the receiver. Its synchronous multichannel operation is supported by excellent timing stability and low power consumption of miniature size modules based upon custom integrated SiGe circuits. The paper describes the architecture, design, calibration, basic parameters, and application examples of the sounding system.

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Martin Kmec

Papers

Remote vital sign detection for rescue, security, and medical care by ultra-wideband pseudo-noise radar

Recent Advances and Applications of M-Sequence based Ultra-Wideband Sensors

Liquid and moisture sensing by ultra-wideband pseudo-noise sequence signals

Ultra wideband radar assembly kit

Real-Time MIMO Channel Sounder for Emulation of Distributed Ultrawideband Systems