Signal model and linearization for nonlinear chirps in FMCW Radar SAW-ID tag request

Scheiblhofer, Stefan; Schuster, Stefan; Stelzer, Andreas

doi:10.1109/tmtt.2006.871361

Cited by 47 publications

(20 citation statements)

References 7 publications

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“…We correct for this using the efficient technique presented in [18]. The linearization re-samples the beat spectrum and corrects for first-order non-linearity in the chirp, the idea starts by equating the measured beat with a constant frequency sine wave…”

Section: A) Fmcw Linearity Correctionmentioning

confidence: 99%

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Bitstream radar waveforms for generic single-chip radar

Bjorndal

Hamran

Lande

2017

Int. J. Microw. Wireless Technol.

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Bitstreams, square wave digital signals, enable flexible radar implementations in modern digital technology. By using bitstreams in place of analog sinusoidal waveforms, we can realize continuous-wave (CW), stepped-frequency CW, frequencymodulated CW, or even pseudo random noise-sequence and pulsed radars, all with a single bit of amplitude resolution. The building blocks are a programable waveform generator, a sweep threshold quantizer, digital delay, and a digital XOR gate as a mixer. This gives us a novel, almost fully digital (requiring only a comparator) system, as previously proposed and which is extended here. The flexibility of the transmitter allows for easy switching between waveforms and the bitstream signal can be processed with single-bit digital gates. Single-bit signals allows for exploration of novel continuous time non-clocked digital implementations to maximize speed and energy efficiency. Mixing frequencies with a digital XOR gate creates harmonics, which are explored for multiple solutions utilizing digital delay. Analytical as well as simulation results are presented. Initial measurements from a 90 nm CMOS chip is provided for the transmitter and the full system, proving the feasibility of a digital future in radar.Keywords: Radar architecture and systems, Si-based devices and IC technologies I . I N T R O D U C T I O NModern digital technology bring miniaturization, low-power consumption, substantial computational power, and integration of complex processing on a small piece of silicon (system-on-chip). For modern radar systems, the full advantage of modern technology has been difficult to utilize in spite of faster devices and higher computational speed. As indicated in [1] modern radar systems are still fairly large modules with substantial size and power consumption.The basic principles of radar have been known for more than a century, over the years several radar architectures have been explored; each with its own tradeoff in application and hardware complexity. Radar architectures differ mainly by the utilized waveform, example architectures contains, continuous-wave (CW) radar for velocity determination, pulsed ranging radar, frequency-modulated continuous-wave (FMCW) radar, stepped-frequency continuous-wave (SFCW) radar, and noise radar. The frequency-modulated architectures need a frequency source and a mixer, but require only a modest sampling rate of the mixer difference. The pulsed and noise radars are more amendable to digital implementation, but require a receiver that samples the entire transmitted bandwidth.Several integrated radar systems have appeared in the literature, some with commercial interest. The first single-chip complementary metal-oxide-semiconductor (CMOS) radar was published by Hjortland et al. [2] in 2006, featuring a pulsed radar system now commercially available from Novelda [3]. Later an integrated SFCW radar was reported in 65 nm CMOS by Caruso [4] for breast cancer detection. Sachs [5] has written extensively on a M-sequence radar using SiGe BiCMOS techn...

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Section: A) Fmcw Linearity Correctionmentioning

confidence: 99%

“…where a 2 is the unwanted first-order non-linearity term, we can solve (18) to obtain our new sampling locations…”

Section: A) Fmcw Linearity Correctionmentioning

confidence: 99%

Bitstream radar waveforms for generic single-chip radar

Bjorndal

Hamran

Lande

2017

Int. J. Microw. Wireless Technol.

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“…The analytical discrete signal model s IF [n] for a single point target or a single reflector [29], [30] is stated as…”

Section: B Signal Modelmentioning

confidence: 99%

Model-Based Identification Method for Pulse Position Coded Surface Acoustic Wave Identification Tags

Klaffenböck

Schuster

Scheiblhofer³

et al. 2014

IEEE Trans. Instrum. Meas.

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In this paper, a novel code identification algorithm based on a least squares reflector grid estimation technique for single delay-line-based surface acoustic wave (SAW) sensor identification tags using pulse position coding is derived. The least squares estimation procedure considers all round-trip delay time information encoded on a single tag. Hence, the pulse position coding grid can be estimated with higher accuracy compared with the standard grid estimation technique, which uses only framing reflectors for grid calculation. The need for framing reflectors is completely eliminated, and thus additional space for data on the tag is obtained. With a more accurate grid, the probability of correct identification increases. Ensuring a large data capacity on the SAW tag, the newly derived estimator also works well with fine pulse position coding grids, for which common grid estimators fail, in particular, in low signal-to-noise ratio scenarios.Index Terms-Parameter estimation, signal processing, surface acoustic wave delay lines, surface acoustic wave signal processing, surface acoustic waves.

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“…The FMCW radar is equipped with a fast direct digital synthesis (DDS) based frequency synthesizer that provides fast frequency sweeps of 100 µs duration (Figure 3). The DDS works with a frequency predistortion to combat non-linear frequency chirps as reported in (Scheiblhofer, 2006). The Tx and Rx paths have separate antennas to achieve better signal isolation.…”

Section: Reader Systems For Saw Transpondermentioning

confidence: 99%