Design, fabrication, and application of precise SAW delay lines used in an FMCW radar system

Reindl, L.; Ruppel, C.C.W.; Berek, S.; Knauer, U.; Vossiek, Martin; Heide, P.; Oréans, L.

doi:10.1109/22.915465

Cited by 58 publications

(19 citation statements)

References 36 publications

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“…The extended frequency band, ranging up to B = 500 MHz around 2.25 GHz, yields significantly increased informative capacity, provinding the entropy needed to prevent collision and allow for tag identification. It will be experimentally shown in this paper that thanks to short compressed signals, 1/B 2 ns, hence including only a few RF signal periods, the phase ambiguity is avoided [10], allowing for precise measuring delay between 2 pulses. The narrow compressed pulse is compatible with an increased number of sensors operating simultaneously, and measurements in an environment with strong reflections and multipath propagation.…”

Section: Introductionmentioning

confidence: 99%

Ultra-wide-band SAW sensors and tags

Lamothe

Plessky²,

Ostertag³

et al. 2013

2013 Joint European Frequency and Time Forum &Amp; International Frequency Control Symposium (EFTF/IFC)

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SAW tags and sensors often operate in 2.45 GHz ISM band using relatively narrow frequency Band = 82.5 MHz available there. The characteristics of these devices can be improved using the ultra wide band (UWB) technology. We have developed prototype devices operating in 200 MHz-400 MHz and 2000 MHz -2500 MHz UWB frequency ranges. The UWB reader operating in continuous wave radar mode for 2 GHz range was developed and manufactured. The first remote measurements have shown that we get compressed RF pulses of about 2 ns duration, which include unique RF filing of a few sinusoids with amplitude modulation. The precise measurement of the pulse position is possible by correlation methods, avoiding the phase ambiguity problem.The temperature is measured with a precisions of about 0.1 • C degree Celsius. Only 2 reflectors are necessary for such a sensor. The correlation method works even in multi-path environment with strong reflections form metal objects. The short compressed pulses allow measuring a number of sensors simultaneously just separating them in time. For tag application, we measure and identify three different tags at the same time without collision problem, this number can easily be increased. For such limited number of tags there is no "collision" problem.

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Section: Introductionmentioning

confidence: 99%

Ultra-wide-band SAW sensors and tags

Lamothe

Plessky²,

Ostertag³

et al. 2013

2013 Joint European Frequency and Time Forum &Amp; International Frequency Control Symposium (EFTF/IFC)

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“…There exist two major approaches to implement the pulse compression which are: 1) Analog and 2) Digital approaches. The first approach comprised of delay line devices (DLD) [4] and surface acoustic wave (SAW) [5] devices which apply too much losses on the signal in duration of the pulse compression process. The digital approach consists of two main categories of linear (including stretch and correlation processing [3]) and non-linear methods [2].…”

Section: Introductionmentioning

confidence: 99%

A novel approach for implementing high speed pulse compression based on linear frequency modulation

Karami

Farahani

Sadeghzadeh

2012

2012 IEEE Asia-Pacific Conference on Applied Electromagnetics (APACE)

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In this paper, a novel approach based on digital linear frequency modulation (LFM) is proposed to implement high speed pulse compression. The main objective is to achieve high speed pulse compression for high range resolution in target detection using modified Fast Fourier Transformation (FFT) input/output (I/O) data flow algorithm. The digital processing cycle (DPC) factor of the proposed method is investigated in comparison with previous works. The results of both simulation and implementation show 99.8% improvement in the FFT calculation time and pulse compression ratio of 71% in the proposed method. This method eliminates the drawbacks of the methods proposed for pulse compression in previous works. In addition, the proposed method has the advantages of high signal to noise ratio (SNR), and good detection of low amplitude level signals.

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“…Different to the problem at hand, the system is built with discrete components, allowing for a wide range for the delay. In [11], [12] the delay is realized with surface acoustic wave (SAW) technology. However, since the SAW technology has a transit frequency in the low GHz range, an additional local oscillator is required to downconvert the actual radar transmit signal.…”

Section: Introductionmentioning

confidence: 99%

Short-Range Leakage Cancelation in FMCW Radar Transceivers Using an Artificial On-Chip Target

Melzer

Onic²,

Starzer³

et al. 2015

IEEE J. Sel. Top. Signal Process.

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A major drawback of frequency modulated continuous-wave (FMCW) radar systems is the permanent leakage from the transmit into the receive path. Besides leakage within the radar device itself, signal reflections from a fixed object in front of the antennas additionally introduce so-called short-range (SR) leakage. It causes a strong degradation of detection sensitivity due to the unpreventable phase noise of the transmit oscillator. In this work, we introduce an artificial on-chip target (OCT) to mitigate the SR leakage. The OCT consists of a delay line whose time delay is significantly smaller than the round-trip delay time of the SR leakage. This is motivated by the fact that in integrated circuits for automotive radar applications operating at 77 GHz delay lines in the range of only a few picoseconds can be realized with a reasonable amount of circuitry. Despite this constraint, we show that the proposed method achieves almost perfect cancelation of the SR leakage. The concept is based on the cross-correlation properties of the residual phase noise in the intermediate frequency (IF) domain. Further, the effectiveness of the proposed method is verified in an FMCW radar system simulation. It almost perfectly shows that a gain in sensitivity of approximately 6 dB is achieved, compensating for the performance degradation caused by the SR leakage. The novel leakage cancelation concept is carried out mainly in the digital domain enabling high flexibility and adaptivity.Index Terms-Digital signal processing, frequency modulated continuous-wave (FMCW) radar, leakage cancelation, phase noise, reflected power canceler.

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Design, fabrication, and application of precise SAW delay lines used in an FMCW radar system

Cited by 58 publications

References 36 publications

Ultra-wide-band SAW sensors and tags

Ultra-wide-band SAW sensors and tags

A novel approach for implementing high speed pulse compression based on linear frequency modulation

Short-Range Leakage Cancelation in FMCW Radar Transceivers Using an Artificial On-Chip Target

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