Akanksha Bhutani

An Efficient Frequency and Phase Estimation Algorithm With CRB Performance for FMCW Radar Applications

In this paper, a chirp z-transform (CZT)-based algorithm for frequency-modulated continuous wave (FMCW) radar applications is presented. The proposed algorithm is optimized for real-time implementation in field-programmable gate arrays. To achieve a very high accuracy, the FMCW radar uses an additional phase evaluation. Therefore, a phase calculation based on the CZT algorithm is derived and compared with a correlation based algorithm. For a better classification of the algorithm, the respective Cramér-Rao bounds are calculated. The performance of the algorithm is shown by the evaluation of different radar measurements with a K-band radar. In the measurements, an accuracy of 5 μm with a mean standard deviation of 774 nm is achieved, which nearly matches the theoretically predicted mean standard deviation of 160 nm.

Impact of Frequency Ramp Nonlinearity, Phase Noise, and SNR on FMCW Radar Accuracy

One of the main disturbances in a frequency-modulated continuous wave radar system for range measurement is nonlinearity in the frequency ramp. The intermediate frequency (IF) signal and consequently the target range accuracy are dependent on the type of the nonlinearity present in the frequency ramp. Moreover, the type of frequency ramp nonlinearity cannot be directly specified, which makes the problem even more challenging. In this paper, the frequency ramp nonlinearity is investigated with the modified short-time Fourier transform method by using the short-time Chirp-Z transform method with high accuracy. The random and periodic nonlinearities are characterized and their sources are identified as phase noise and spurious. These types of frequency deviations are intentionally increased, and their influence on the linearity and the IF-signal is investigated. The dependence of target range estimation accuracy on the frequency ramp nonlinearity, phase noise, spurious, and signal-to-noise ratio in the IF-signal are described analytically and are verified on the basis of measurements.

Miniaturized Millimeter-Wave Radar Sensor for High-Accuracy Applications

A highly miniaturized and commercially available millimeter wave (mmw) radar sensor working in the frequency range between 121 and 127 GHz is presented in this paper. It can be used for distance measurements with an accuracy in the single-digit micrometer range. The sensor is based on the frequency modulated continuous wave (CW) radar principle; however, CW measurements are also possible due to its versatile design. An overview of the existing mmw radar sensors is given and the integrated radar sensor is shown in detail. The radio frequency part of the radar, which is implemented in SiGe technology, is described followed by the packaging concept. The radar circuitry on chip as well as the external antennas is completely integrated into an 8 mm

Ultra broadband multiple feed antenna for efficient on-chip power combining

\times \,\, 8

Packaging Solution for a Millimeter-Wave System-on-Chip Radar

mm quad flat no leads package that is mounted on a low-cost baseband board. The packaging concept and the complete baseband hardware are explained in detail. A two-step approach is used for the radar signal evaluation: a coarse determination of the target position by the evaluation of the beat frequency combined with an additional determination of the phase of the signal. This leads to an accuracy within a single-digit micrometer range. The measurement results prove that an accuracy of better than

Millimeter-Wave Radar Sensor for Snow Height Measurements

\pm 6~\mu \text{m}

Radar Sensor for Waveguide Based Distance Measurements in Machine Tool Components

can be achieved with the sensor over a measurement distance of 35 mm.

Bandwidth Optimization Method for Reflective-Type Phase Shifters

A multiple feed on-chip antenna is realized in a SiGe seven metal layer backend process. The principle of an integrated lens antenna (ILA) is used and this work presents the proof-of-concept for a power-combining antenna since it can be directly connected to differential amplifiers. For measurements an adequate feeding network has to be designed which should provide the same broadband characteristic as the antenna itself. The measured antenna reaches a return loss better than -10 dB in a frequency range of 210 to 320 GHz and a realized gain of 17.5 to 23 dBi, including a power-splitter. The simulated efficiency of the on-chip antenna element, excluding the feeding network, exceeds 75%.

Influence of Radar Targets on the Accuracy of FMCW Radar Distance Measurements

In this paper, a packaging solution for millimeter-wave system-on-chip (SoC) radio transceivers is presented. The on-chip antennas are realized as primary radiators of an integrated lens antenna which offer high bandwidth and high efficiency. The package concept includes a high permittivity silicon lens which serves additionally as heat sink and a quad flat no-lead package which is mountable on a standard printed circuit board (PCB). The electrical and thermal properties of the package are investigated through simulations and calibrated measurements. The concept is verified by realizing a complete radar sensor. The manufactured SoC radar frontend is soldered on a standard PCB which includes the baseband circuitry for a frequency-modulated continuous wave radar and finally, measurements are performed to compare the superposed radiation patterns of the transmit and receive antennas with simulations.

Pea-Sized mmW Transceivers: QFN-?Based Packaging Concepts for Millimeter-Wave Transceivers

A small and lightweight frequency-modulated continuous-wave (FMCW) radar system is used for the determination of snow height by measuring the distance to the snow surface from a platform. The measurements have been performed at the Centre des Études de la Neige (Col de Porte), which is located near Grenoble in the French Alps. It is shown that the FMCW radar at millimeter-wave frequencies is an extremely promising approach for distance measurements to snow surfaces, e.g., in the mountains or in an Arctic environment. The characteristics of the radar sensor are described in detail. The relevant accuracy to measure the distance to a snow layer is shown at different heights and over an extended time duration. A dedicated laser snow telemeter is used as reference. In addition, the reflection from different types of snow is shown.