sensors-logo

Journal Browser

Journal Browser

Millimeter Wave and THz Integrated Systems and Radar Sensors

A special issue of Sensors (ISSN 1424-8220). This special issue belongs to the section "Physical Sensors".

Deadline for manuscript submissions: closed (31 May 2019) | Viewed by 29451

Special Issue Editor

Institute of Radio Frequency Engineering and Electronics (IHE), Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
Interests: radio wave propagation; radio channel modeling and measurement techniques; microwave techniques; wireless communications; antennas and antenna systems; radar technology (radar architectures, signal processing, automotive and industrial applications)

Special Issue Information

Dear Colleagues,

Semiconductor technologies have made tremendous progress in the last 20 years, advancing towards THz frequencies and regarding integration. This enables novel solutions for millimeter wave and THz integrated systems for a large variety of applications, from all kinds of sensors to gigabit communication radios. This call for a Special Issue of Sensors invites contributions from scientists and engineers from all disciplines involved with innovations regarding the realization of such novel devices and systems. This includes integrated circuits, packaging solutions, completely integrated systems, as well as application-related research.

Prof. Dr. Thomas Zwick
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Sensors is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Integrated Millimeter Wave and THz Transceivers
  • Highly Integrated Radar Sensors
  • Millimeter Wave System on Chip (SoC)
  • Millimeter Wave System in Package (SiP)
  • Miniaturized Millimeter Wave Systems

Published Papers (5 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

16 pages, 5960 KiB  
Article
The Role of Millimeter-Waves in the Distance Measurement Accuracy of an FMCW Radar Sensor
by Akanksha Bhutani, Sören Marahrens, Michael Gehringer, Benjamin Göttel, Mario Pauli and Thomas Zwick
Sensors 2019, 19(18), 3938; https://doi.org/10.3390/s19183938 - 12 Sep 2019
Cited by 20 | Viewed by 6478
Abstract
High-accuracy, short-range distance measurement is required in a variety of industrial applications e.g., positioning of robots in a fully automated production process, level measurement of liquids in small containers. An FMCW radar sensor is suitable for this purpose, since many of these applications [...] Read more.
High-accuracy, short-range distance measurement is required in a variety of industrial applications e.g., positioning of robots in a fully automated production process, level measurement of liquids in small containers. An FMCW radar sensor is suitable for this purpose, since many of these applications involve harsh environments. Due to the progress in the field of semiconductor technology, FMCW radar sensors operating in different millimeter-wave frequency bands are available today. An important question in this context, which has not been investigated so far is how does a millimeter-wave frequency band influence the sensor accuracy, when thousands of distance measurements are performed with a sensor. This topic has been dealt with for the first time in this paper. The method used for analyzing the FMCW radar signal combines a frequency- and phase-estimation algorithm. The frequency-estimation algorithm based on the fast Fourier transform and the chirp-z transform provides a coarse estimate of the target distance. Subsequently, the phase-estimation algorithm based on a cross-correlation function provides a fine estimate of the target distance. The novel aspects of this paper are as follows. First, the estimation theory concept of Cramér-Rao lower bound (CRLB) has been used to compare the accuracy of two millimeter-wave FMCW radars operating at 60 GHz and 122 GHz. In this comparison, the measurement parameters (e.g., bandwidth, signal-to-noise ratio) as well as the signal-processing algorithm used for both the radars are the same, thus ensuring an unbiased comparison of the FMCW radars, solely based on the choice of millimeter-wave frequency band. Second, the improvement in distance measurement accuracy obtained after each step of the combined frequency- and phase-estimation algorithm has been experimentally demonstrated for both the radars. A total of 5100 short-range distance measurements are made using the 60 GHz and 122 GHz FMCW radar. The measurement results are analyzed at various stages of the frequency- and phase-estimation algorithm and the measurement error is calculated using a nanometer-precision linear motor. At every stage, the mean error values measured with the 60 GHz and 122 GHz FMCW radars are compared. The final accuracy achieved using both radars is of the order of a few micrometers. The measured standard deviation values of the 60 GHz and 122 GHz FMCW radar have been compared against the CRLB. As predicted by the CRLB, this paper experimentally validates for the first time that the 122 GHz FMCW radar provides a higher repeatability of micrometer-accuracy distance measurements than the 60 GHz FMCW radar. Full article
(This article belongs to the Special Issue Millimeter Wave and THz Integrated Systems and Radar Sensors)
Show Figures

Figure 1

16 pages, 2023 KiB  
Article
Accuracy Bounds and Measurements of a Contactless Permittivity Sensor for Gases Using Synchronized Low-Cost mm-Wave Frequency Modulated Continuous Wave Radar Transceivers
by Andreas Och, Jochen O. Schrattenecker, Stefan Schuster, Patrick A. Hölzl, Philipp F. Freidl, Stefan Scheiblhofer, Dominik Zankl and Robert Weigel
Sensors 2019, 19(15), 3351; https://doi.org/10.3390/s19153351 - 31 Jul 2019
Cited by 5 | Viewed by 3512
Abstract
A primary concern in a multitude of industrial processes is the precise monitoring of gaseous substances to ensure proper operating conditions. However, many traditional technologies are not suitable for operation under harsh environmental conditions. Radar-based time-of-flight permittivity measurements have been proposed as alternative [...] Read more.
A primary concern in a multitude of industrial processes is the precise monitoring of gaseous substances to ensure proper operating conditions. However, many traditional technologies are not suitable for operation under harsh environmental conditions. Radar-based time-of-flight permittivity measurements have been proposed as alternative but suffer from high cost and limited accuracy in highly cluttered industrial plants. This paper examines the performance limits of low-cost frequency-modulated continuous-wave (FMCW) radar sensors for permittivity measurements. First, the accuracy limits are investigated theoretically and the Cramér-Rao lower bounds for time-of-flight based permittivity and concentration measurements are derived. In addition, Monte-Carlo simulations are carried out to validate the analytical solutions. The capabilities of the measurement concept are then demonstrated with different binary gas mixtures of Helium and Carbon Dioxide in air. A low-cost time-of-flight sensor based on two synchronized fully-integrated millimeter-wave (MMW) radar transceivers is developed and evaluated. A method to compensate systematic deviations caused by the measurement setup is proposed and implemented. The theoretical discussion underlines the necessity of exploiting the information contained in the signal phase to achieve the desired accuracy. Results of various permittivity and gas concentration measurements are in good accordance to reference sensors and measurements with a commercial vector network analyzer (VNA). In conclusion, the proposed radar-based low-cost sensor solution shows promising performance for the intended use in demanding industrial applications. Full article
(This article belongs to the Special Issue Millimeter Wave and THz Integrated Systems and Radar Sensors)
Show Figures

Figure 1

18 pages, 4067 KiB  
Article
Assessment of Bandaged Burn Wounds Using Porcine Skin and Millimetric Radiometry
by Amani Yousef Owda, Neil Salmon, Sergiy Shylo and Majdi Owda
Sensors 2019, 19(13), 2950; https://doi.org/10.3390/s19132950 - 04 Jul 2019
Cited by 19 | Viewed by 6412
Abstract
This paper describes the experimental setup and measurements of the emissivity of porcine skin samples over the band of 80–100 GHz. Measurements were conducted on samples with and without dressing materials and before and after the application of localized heat treatments. Experimental measurements [...] Read more.
This paper describes the experimental setup and measurements of the emissivity of porcine skin samples over the band of 80–100 GHz. Measurements were conducted on samples with and without dressing materials and before and after the application of localized heat treatments. Experimental measurements indicate that the differences in the mean emissivity values between unburned skin and burned damaged skin was up to ~0.28, with an experimental measurement uncertainty of ±0.005. Measured differences in the mean emissivity values between unburned and burn damaged skin increases with the depth of the burn, indicating a possible non-contact technique for assessing the degree of a burn. The mean emissivity of the dressed burned skin was found to be slightly higher than the undressed burned skin, typically ~0.01 to ~0.02 higher. This indicates that the signature of the burn caused by the application of localized heat treatments is observable through dressing materials. These findings reveal that radiometry, as a non-contact method, is capable of distinguishing between normal and burn-damaged skin under dressing materials without their often-painful removal. This indicates the potential of using millimeter wave (MMW) radiometry as a new type of medical diagnostic to monitor burn wounds. Full article
(This article belongs to the Special Issue Millimeter Wave and THz Integrated Systems and Radar Sensors)
Show Figures

Figure 1

12 pages, 9492 KiB  
Article
A Wideband Dielectric Waveguide-Based 160-GHz Radar Target Generator
by Martin Geiger, Christian Wegner, Winfried Mayer and Christian Waldschmidt
Sensors 2019, 19(12), 2801; https://doi.org/10.3390/s19122801 - 22 Jun 2019
Cited by 2 | Viewed by 3683
Abstract
The increasing number of radar sensors in commercial and industrial products leads to a growing demand for system functionality tests. Conventional test procedures require expensive anechoic chambers to provide a defined test environment for radar sensors. In this paper, a compact and low [...] Read more.
The increasing number of radar sensors in commercial and industrial products leads to a growing demand for system functionality tests. Conventional test procedures require expensive anechoic chambers to provide a defined test environment for radar sensors. In this paper, a compact and low cost dielectric waveguide radar target generator for level probing radars is presented. The radar target generator principle is based on a long dielectric waveguide as a one-target scenery. By manipulating the field distribution of the waveguide, a specific reflection of a radar target is generated. Two realistic scenarios for a tank level probing radar are investigated and suitable targets are designed with full wave simulations. Target distances from 13 cm to at least 9 m are realized with an extruded dielectric waveguide with dielectric losses of 2 dB/m at 160 GHz. Low loss (0.5 dB) and low reflection holders are used to fix the waveguide. Due to the dispersion of the dielectric waveguide, a detailed analysis of its impact on frequency-modulated continuous wave (FMCW) radars is given and compared to free-space propagation. The functionality of the radar target generator is verified with a 160-GHz FMCW radar prototype. Full article
(This article belongs to the Special Issue Millimeter Wave and THz Integrated Systems and Radar Sensors)
Show Figures

Figure 1

Review

Jump to: Research

32 pages, 3243 KiB  
Review
Emerging Transistor Technologies Capable of Terahertz Amplification: A Way to Re-Engineer Terahertz Radar Sensors
by Mladen Božanić and Saurabh Sinha
Sensors 2019, 19(11), 2454; https://doi.org/10.3390/s19112454 - 29 May 2019
Cited by 42 | Viewed by 8668
Abstract
This paper reviews the state of emerging transistor technologies capable of terahertz amplification, as well as the state of transistor modeling as required in terahertz electronic circuit research. Commercial terahertz radar sensors of today are being built using bulky and expensive technologies such [...] Read more.
This paper reviews the state of emerging transistor technologies capable of terahertz amplification, as well as the state of transistor modeling as required in terahertz electronic circuit research. Commercial terahertz radar sensors of today are being built using bulky and expensive technologies such as Schottky diode detectors and lasers, as well as using some emerging detection methods. Meanwhile, a considerable amount of research effort has recently been invested in process development and modeling of transistor technologies capable of amplifying in the terahertz band. Indium phosphide (InP) transistors have been able to reach maximum oscillation frequency (fmax) values of over 1 THz for around a decade already, while silicon-germanium bipolar complementary metal-oxide semiconductor (BiCMOS) compatible heterojunction bipolar transistors have only recently crossed the fmax = 0.7 THz mark. While it seems that the InP technology could be the ultimate terahertz technology, according to the fmax and related metrics, the BiCMOS technology has the added advantage of lower cost and supporting a wider set of integrated component types. BiCMOS can thus be seen as an enabling factor for re-engineering of complete terahertz radar systems, for the first time fabricated as miniaturized monolithic integrated circuits. Rapid commercial deployment of monolithic terahertz radar chips, furthermore, depends on the accuracy of transistor modeling at these frequencies. Considerations such as fabrication and modeling of passives and antennas, as well as packaging of complete systems, are closely related to the two main contributions of this paper and are also reviewed here. Finally, this paper probes active terahertz circuits that have already been reported and that have the potential to be deployed in a re-engineered terahertz radar sensor system and attempts to predict future directions in re-engineering of monolithic radar sensors. Full article
(This article belongs to the Special Issue Millimeter Wave and THz Integrated Systems and Radar Sensors)
Show Figures

Figure 1

Back to TopTop