Peter Rauschenbach

Ultra wideband radar assembly kit

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.

High resolution non-destructive testing in civil engineering by ultra-wideband pseudo-noise approaches

Ultra-wideband sensing provides new and interesting options for testing and inspection in many different fields. The article will deal with some applications for civil engineering. The advantage of UWB-sensing is the good penetration of the sounding waves through the material under test and its high spatial resolution. A flexible UWB-sensor conception will be discussed. Its working principle is based on pseudo-random sounding waves. The examples considered shall indicate the device performance for quite different sensor tasks.

Trapped victim detection by pseudo-noise radar

Radar based detection of earthquake survivors exploits the modulation of the backscattered signal by body motions of the victim. The most challenging task is the detection 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 detection radar system is considered and some results from field trials are summarized.

Integrated ultra-wideband hardware for MIMO sensing using pn-sequence approach

The article deals with SiGe based hardware for new, flexible ultra-wideband MIMO sensing purposes using pn-sequence approach. Introduced hardware serves as future platform for scientific investigations in the complex field of ultrawideband (UWB) applications. We discuss the design aspects and prototype evaluation of the single chip M-sequence based sensor head as well as realization particularities of the transmit- and receive-front-ends for applications with direct contact measurements. The front-ends are small antenna units with active customized baluns.

M-Sequence-Based Single-Chip UWB-Radar Sensor

The article deals with a fully monolithically integrated single-chip M-sequence-based UWB-radar sensor, its architecture, selected design aspects and first measurement results performed on wafer and with packaged IC modules. The discussed chip is equipped with one transmitter and two receivers. The IC was designed and manufactured in commercially available high-performance 0.25 μm SiGe BiCMOS technology (f t = 110 GHz). Due to the combination of fast digital and broadband analogue system blocks in one chip, special emphasis has been placed on the electrical isolation of these functional structures. The manufactured IC is enclosed in a low-cost QFN (quad flat-pack no-leads) package and mounted on a PCB permitting the creation of MIMO-sensor arrays by cascading a number of modules. In spite of its relatively high complexity, the sensor head features a compact design (chip size of 2 × 1 mm2, QFN package size 5 × 5 mm2) and moderate power consumption (below 1 W at −3 V supply). The assembled transceiver chip can handle signals in the frequency range from near DC up to 18 GHz. This leads to an impulse response (IRF) of FWHD ≈ 50 ps (full width at half duration).

INTEGRATED DIGITAL UWB-RADAR

Ultra wideband (UWB) radar and impedance spectroscopy are of great interest for a vast number of applications such as surface penetrating radar, surveillance and emergency radar, medical instrumentation, non-destructive testing in civil engineering and the food industry, industrial sensors and microwave imaging and many others. The fractional bandwidth of the sounding waves for such types of applications should be as close as possible to 200 % resulting in a high spatial resolution and good penetration in materials. An UWB radar is able to detect hidden objects and a high bandwidth not only results in good spatial resolution but also in improved capabilities for object recognition. Concerning the impedance spectroscopy, a large bandwidth covers different relaxation phenomenon of matter so that more information is available for the substance characterisation. This article will be concentrated on UWB radar rather than on problems of impedance spectroscopy even if both measurement tasks are closely related. The UWB radar measures the time variant impulse response function (IRF) of the scenario of investigation which is determined by the arrangement and movement of scatterer and the illumination of the scene by the antennas. The classical methods of determining a systems impulse response function is based on pulse excitation methods as the function’s name implies. Other methods deal with the determination of the frequency response function (FRF) – a Fourier transformed version of the IRF - over a very large bandwidth. These methods typically use sine-waves which are stepped or swept through the band of interest or a Multi-Sine concept is applied. However all these methods are burdened by critical disadvantages concerning their technical parameters or/and the price (or/and size) of the equipment. In the opinion of the authors, this is the main explanation for the gap between

Experimental active antenna measurement setup for UWB breast cancer detection

Imaging by microwave UWB radar represents a promising technique for early-stage breast cancer detection. We present an experimental measurement setup for breast phantom trials based on M-sequence radar technology and active small antennas (interfacial dipoles). This approach combines short impulse responses, sufficient fidelity and very small antenna dimensions and allows for array construction with an adequate number of antennas around the breast. The presented imaging results illustrate the performance of the method.

Short interfacial antennas for medical microwave imaging

Practical as well as theoretical aspects of medical microwave imaging require short antennas with short impulse response function for transmission and reception of the sounding fields. Since usually antenna design goals are targeted to good feed point matching, one runs into unsolvable problems in case of wideband measurements. The paper will introduce a radar channel model based on electrically short antennas and it will discuss how to circumvent the mismatch problems.