Reverberation chambers show transient behaviour when excited with a pulsed signal. The field intensities can in this case be significantly higher than in steady state, which implies that a transient field can exceed predefined limits and render test results uncertain. Effects of excessive field intensities of short duration may get covered and not be observable in a statistical analysis of the field characteristics. In order to ensure that the signal reaches steady state, the duration of the pulse used to excite the chamber needs to be longer than the time constant of the chamber. Initial computations have shown that the pulse width should be about twice as long as the time constant of the chamber to ensure that steady state is reached. The signal is sampled in the time domain with a sampling frequency according to the Nyquist theorem. The bandwidth of the input signal is determined using spectral analysis. For a fixed stirrer position, the reverberation chamber, wires, connectors, and antennas can jointly be considered as a linear time-invariant system. In this article, a procedure will be presented to extract characteristic signal properties such as rise-time, transient overshoot and the mean value in steady state from the system response. The signal properties are determined by first computing the envelope of the sampled data using a Hilbert transform. Subsequent noise reduction is achieved applying a Savitzky–Golay filter. The point where steady state is reached is then computed from the slope of the envelope by utilising a cumulative histogram. The spectral analysis is not suitable to examine the transient behaviour and determine the time constants of the system. These constants are computed applying the method of Prony, which is based on the estimation of a number of parameters in a sum of exponential functions. An alternative to the Prony Method is the Time-Domain Vector-Fit method. In contrast to the first mentioned variant, it is now also possible to determine the transfer function of the overall RC system. Differences and advantages of the methods will be discussed.
{"title":"Approximation and analysis of transient responses of a reverberation chamber by pulsed excitation","authors":"Konstantin Pasche, Fabian Ossevorth, R. Jacobs","doi":"10.5194/ars-18-53-2020","DOIUrl":"https://doi.org/10.5194/ars-18-53-2020","url":null,"abstract":"Reverberation chambers show transient behaviour when excited with a pulsed signal. The field intensities can in this case be significantly higher than in steady state, which implies that a transient field can exceed predefined limits and render test results uncertain. Effects of excessive field intensities of short duration may get covered and not be observable in a statistical analysis of the field characteristics. In order to ensure that the signal reaches steady state, the duration of the pulse used to excite the chamber needs to be longer than the time constant of the chamber. Initial computations have shown that the pulse width should be about twice as long as the time constant of the chamber to ensure that steady state is reached. The signal is sampled in the time domain with a sampling frequency according to the Nyquist theorem. The bandwidth of the input signal is determined using spectral analysis. For a fixed stirrer position, the reverberation chamber, wires, connectors, and antennas can jointly be considered as a linear time-invariant system. In this article, a procedure will be presented to extract characteristic signal properties such as rise-time, transient overshoot and the mean value in steady state from the system response. The signal properties are determined by first computing the envelope of the sampled data using a Hilbert transform. Subsequent noise reduction is achieved applying a Savitzky–Golay filter. The point where steady state is reached is then computed from the slope of the envelope by utilising a cumulative histogram. The spectral analysis is not suitable to examine the transient behaviour and determine the time constants of the system. These constants are computed applying the method of Prony, which is based on the estimation of a number of parameters in a sum of exponential functions. An alternative to the Prony Method is the Time-Domain Vector-Fit method. In contrast to the first mentioned variant, it is now also possible to determine the transfer function of the overall RC system. Differences and advantages of the methods will be discussed.","PeriodicalId":45093,"journal":{"name":"Advances in Radio Science","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42586468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Boudjada, A. Abou El-fadl, P. Galopeau, E. Al-Haddad, H. Lammer
Abstract. In this study, we report on the occurrence of solar Type III radio bursts recorded by radio and plasma wave experiment (RPWS) experiment onboard Cassini spacecraft. This instrument is designed to investigate the Saturn's plasma environment and sub-auroral radio missions. RPWS/Cassini experiment allows to measure electric field over a frequency range from 1 Hz to 16 MHz (Gurnett et al., 2004). The essential observed emission is associated to the Saturnian Kilometric Radiation (SKR) which is generated in the sub-auroral regions of the magnetosphere. The capability of this experiment leads to detect Solar Type III radio bursts recorded during the increase phase of the solar activity, i.e. January 2008 to December 2014. Hence we have found more than 300 Type III solar bursts when the distance of Cassini to the Sun was about 10 AU. Observational parameters like the time occurrence, the emission frequency and the relative intensity are considered in this analysis. Those features lead us to characterize the detection conditions and to estimate the occurrence variabilities of Type III bursts.
{"title":"Observations of Solar Type III radio bursts by Cassini/RPWS experiment","authors":"M. Boudjada, A. Abou El-fadl, P. Galopeau, E. Al-Haddad, H. Lammer","doi":"10.5194/ars-18-83-2020","DOIUrl":"https://doi.org/10.5194/ars-18-83-2020","url":null,"abstract":"Abstract. In this study, we report on the occurrence of solar Type III radio bursts recorded by radio and plasma wave experiment (RPWS) experiment onboard Cassini spacecraft. This instrument is designed to investigate the Saturn's plasma environment and sub-auroral radio missions. RPWS/Cassini experiment allows to measure electric field over a frequency range from 1 Hz to 16 MHz (Gurnett et al., 2004). The essential observed emission is associated to the Saturnian Kilometric Radiation (SKR) which is generated in the sub-auroral regions of the magnetosphere. The capability of this experiment leads to detect Solar Type III radio bursts recorded during the increase phase of the solar activity, i.e. January 2008 to December 2014. Hence we have found more than 300 Type III solar bursts when the distance of Cassini to the Sun was about 10 AU. Observational parameters like the time occurrence, the emission frequency and the relative intensity are considered in this analysis. Those features lead us to characterize the detection conditions and to estimate the occurrence variabilities of Type III bursts.\u0000","PeriodicalId":45093,"journal":{"name":"Advances in Radio Science","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46629100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. The authors present a microwave-based vital sign monitoring system to detect the breathing rate of premature infants in a baby incubator. The sensor is a four channel I/Q-radar system with adapted antennas to cover the predefined region of interest on the patient surface of the incubator. In order to prove the correct illumination of the reclining area an electromotive actuator and a pneumatic dummy is used. With a periodic and repeatable breathing simulation the reflected signal in the sensor system is measured and evaluated. In the publication the radar system in the baby incubator, the electromotive actuator and the infant dummy are presented.
{"title":"Verification and first test measurement of a microwave-based vital sign monitor","authors":"Daniel Schmiech, Aly Marnach, A. Diewald","doi":"10.5194/ars-17-249-2019","DOIUrl":"https://doi.org/10.5194/ars-17-249-2019","url":null,"abstract":"Abstract. The authors present a microwave-based vital sign monitoring system to detect the breathing rate of premature infants in a baby incubator. The sensor is a four channel I/Q-radar system with adapted antennas to cover the predefined region of interest on the patient surface of the incubator. In order to prove the correct illumination of the reclining area an electromotive actuator and a pneumatic dummy is used.\u0000With a periodic and repeatable breathing simulation the reflected signal in the sensor system is measured and evaluated. In the publication the radar system in the baby incubator, the electromotive actuator and the infant dummy are presented.\u0000","PeriodicalId":45093,"journal":{"name":"Advances in Radio Science","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2019-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45081701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Hirsch, M. Strobel, W. Klingler, Jan Dirk Schulze Spuntrup, Zili Yu, J. Burghartz
Abstract. Conventional CMOS image sensors with a linear transfer characteristic only have a limited dynamic range (DR) of about 60–70 dB. To extend the dynamic range considerably, the already successfully demonstrated concept of a linear self-reset pixel was employed in this work. With the self-reset concept the limit of the maximum analyzable photo generated charge (Qmax) during the exposure time is extended to a multiple of the saturation charge of the photo diode (Qsat) by asynchronous self-resets of the photo diode. Additionally, the remaining charge at the end of the exposure time is evaluated to increase the resolution of the opto-electronic conversion. Thus we achieved pixels with a DR of more than 120 dB combined with an improved low light sensitivity using a pinned photodiode. This paper focuses on two topics: One is the realization and opto-electronic characterization of further self-reset pixel cells for an experimental optimization of the functionality with respect to linearity and high signal-to-noise ratio. The second one is the assembly and digital readout of a cluster structure composed of 16 × 16 pixel matrix on a CMOS test chip. One constraint for later usage of the pixel cells in a high resolution (> VGA) image sensor is the required layout area of the individual circuit blocks. For the cluster structure a size of 20 × 20 µm2 for the analog part of the pixel containing the photo diode and the other analog circuit blocks, the comparator and the signal shaping, was desired. The circuit design and layout work included several variants of the pinned photo diode with floating diffusion (FD) readout node, which is also used for analog voltage storage, and different control transistors. Further for the comparator a telescopic differential amplifier with high gain was implemented as well as peripheral 10 bit counter/shift register as static and dynamic versions. Test chips have been fabricated in an advanced 0.18 µm CMOS technology for optical sensors with low leakage currents. The sensor chips have been evaluated with a specifically developed test setup which gives the flexibility to arbitrarily generate the digital and analog control signals in terms of timing and voltage levels. Based on this, the number of asynchronous self-resets could be read out from the counters of the pixel cells as coarse values. The remaining charge at the end of the integration time was digitized using a ramp analog to digital conversion and could be read out as fine values. An opto-electronic characterization with adjustable illumination from 0 lx to 13 klx was done to measure and analyze the opto-electronic conversion function (OECF) and the noise of six different self-reset pixel cells having the high-gain differential amplifier as comparator. Finally the coarse values of two implemented 16 × 16 pixel clusters could be read out as a mini camera using a lens for optical image formation.
{"title":"Realization and opto-electronic Characterization of linear Self-Reset Pixel Cells for a high dynamic CMOS Image Sensor","authors":"S. Hirsch, M. Strobel, W. Klingler, Jan Dirk Schulze Spuntrup, Zili Yu, J. Burghartz","doi":"10.5194/ars-17-239-2019","DOIUrl":"https://doi.org/10.5194/ars-17-239-2019","url":null,"abstract":"Abstract. Conventional CMOS image sensors with a linear transfer\u0000characteristic only have a limited dynamic range (DR) of about 60–70 dB. To\u0000extend the dynamic range considerably, the already successfully demonstrated\u0000concept of a linear self-reset pixel was employed in this work. With the\u0000self-reset concept the limit of the maximum analyzable photo generated\u0000charge (Qmax) during the exposure time is extended to a multiple of the\u0000saturation charge of the photo diode (Qsat) by asynchronous self-resets of\u0000the photo diode. Additionally, the remaining charge at the end of the\u0000exposure time is evaluated to increase the resolution of the opto-electronic\u0000conversion. Thus we achieved pixels with a DR of more than 120 dB combined\u0000with an improved low light sensitivity using a pinned photodiode. This paper focuses on two topics: One is the realization and opto-electronic\u0000characterization of further self-reset pixel cells for an experimental\u0000optimization of the functionality with respect to linearity and high\u0000signal-to-noise ratio. The second one is the assembly and digital readout of\u0000a cluster structure composed of 16 × 16 pixel matrix on a CMOS test chip.\u0000One constraint for later usage of the pixel cells in a high resolution\u0000(> VGA) image sensor is the required layout area of the\u0000individual circuit blocks. For the cluster structure a size of 20 × 20 µm2 for the analog part of the pixel containing the photo diode\u0000and the other analog circuit blocks, the comparator and the signal shaping,\u0000was desired. The circuit design and layout work included several variants of\u0000the pinned photo diode with floating diffusion (FD) readout node, which is\u0000also used for analog voltage storage, and different control transistors.\u0000Further for the comparator a telescopic differential amplifier with high\u0000gain was implemented as well as peripheral 10 bit counter/shift register as\u0000static and dynamic versions. Test chips have been fabricated in an advanced\u00000.18 µm CMOS technology for optical sensors with low leakage\u0000currents. The sensor chips have been evaluated with a specifically developed test\u0000setup which gives the flexibility to arbitrarily generate the digital and\u0000analog control signals in terms of timing and voltage levels. Based on this,\u0000the number of asynchronous self-resets could be read out from the counters\u0000of the pixel cells as coarse values. The remaining charge at the end of the\u0000integration time was digitized using a ramp analog to digital conversion and\u0000could be read out as fine values. An opto-electronic characterization with\u0000adjustable illumination from 0 lx to 13 klx was done to measure and analyze\u0000the opto-electronic conversion function (OECF) and the noise of six\u0000different self-reset pixel cells having the high-gain differential amplifier\u0000as comparator. Finally the coarse values of two implemented 16 × 16 pixel\u0000clusters could be read out as a mini camera using a lens for optical image\u0000formation.\u0000","PeriodicalId":45093,"journal":{"name":"Advances in Radio Science","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2019-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44845672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Using dielectrics instead of conventional metallic structures, this article investigates the properties of the proposed dielectric corner reflectors for use in a number of millimeter wave (mmWave) applications. Material characterizations of different typical plastics using transmission measurements are presented, as well as an analysis of their respective radar cross section (RCS) when used as corner reflectors. They exhibit similar behavior as conventional metallic ones, while intrinsic dielectric losses reduce the overall RCS. Additionally, two use cases are presented. One shows the potential capabilities by combining a dielectric with a metallic corner reflector to increase its opening angle. The other gives rise to the possibility of using several single dielectric reflectors in array configurations to further increase the overall RCS, while introducing grating lobes.
{"title":"Dielectric corner reflectors for mmWave applications","authors":"C. Buchberger, F. Pfeiffer, E. Biebl","doi":"10.5194/ars-17-197-2019","DOIUrl":"https://doi.org/10.5194/ars-17-197-2019","url":null,"abstract":"Abstract. Using dielectrics instead of conventional metallic structures, this article investigates the properties of the proposed dielectric corner reflectors for use in a number of millimeter wave (mmWave) applications. Material characterizations of different typical plastics using transmission measurements are presented, as well as an analysis of their respective radar cross section (RCS) when used as corner reflectors. They exhibit similar behavior as conventional metallic ones, while intrinsic dielectric losses reduce the overall RCS. Additionally, two use cases are presented. One shows the potential capabilities by combining a dielectric with a metallic corner reflector to increase its opening angle. The other gives rise to the possibility of using several single dielectric reflectors in array configurations to further increase the overall RCS, while introducing grating lobes.\u0000","PeriodicalId":45093,"journal":{"name":"Advances in Radio Science","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2019-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48880331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. This paper presents a 10-bit tracking ADC using a multi-bit quantiser and a segmented current-steering DAC. The quantiser allows a dynamical adjustment of the step size dependent on the input signal waveform. This mitigates the limited slew rate of delta encoded ADCs. Energy consumption induced by 1 LSB ripple is removed by the quantiser. The segmented current-steering DAC allows simple control, good monotonicity and improved transient response when compared to previous design as well as potential power reduction.
{"title":"10-bit tracking ADC with a multi-bit quantizer, variable step size and segmented current-steering DAC","authors":"Stefan Bramburger, D. Killat","doi":"10.5194/ars-17-161-2019","DOIUrl":"https://doi.org/10.5194/ars-17-161-2019","url":null,"abstract":"Abstract. This paper presents a 10-bit tracking ADC using a multi-bit quantiser and a segmented current-steering DAC. The quantiser allows a dynamical adjustment of the step size dependent on the input signal waveform. This mitigates the limited slew rate of delta encoded ADCs. Energy consumption induced by 1 LSB ripple is removed by the quantiser. The segmented current-steering DAC allows simple control, good monotonicity and improved transient response when compared to previous design as well as potential power reduction.\u0000","PeriodicalId":45093,"journal":{"name":"Advances in Radio Science","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2019-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48580998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Wireless energy transfer is often used in industrial applications to power actors or sensors, for example in rotating applications as replacement for mechanical slip rings. In addition to the energy transfer, we have developed inductively coupled data transfer systems to expand the range of possible applications. The data transfer is accomplished by using loosely coupled coils on both sides of the power transfer system. In pure energy transfer systems, resonant coupling is used, meaning that the power transfer coils are both tuned to a common frequency to compensate the relatively small coupling factor between power transmitter and receiver and to achieve an impedance matching between both sides by compensating the inductive component of the transfer coils. In this case, capacitors can be connected in series or in parallel to the coils, leading to a sharp, narrow band resonance peak in the transfer function. In inductively coupled data transfer systems, this approach is often not useful because not just a pure sine wave has to be transferred but more likely a signal of a certain bandwidth. In one of our applications, a 100 Mbit s−1 Ethernet stream is transferred with an occupied bandwidth of 62.5 MHz. The coil structures used so far in our data transfer applications were intrinsically unmatched to the data transfer systems. Additionally, due to the small coupling factor between the data transfer coils, transfer losses in the range of up to 15 dB or worth had to be accepted. This is especially critical regarding the high noise level in vicinity of the energy transfer system and the cross coupling between the two transfer channels. For passive, lossless circuits, Foster's theorem states that the reactance increases monotonically with frequency. Subsequently, the inductive part of a circuit can just be exactly compensated with a capacitance for one single frequency. In contrast, active circuits like a negative impedance converter (NIC) can be used to achieve a non-Foster behaviour, for example a negative inductance can be realized. In theory, an inductance in series or parallel to a negative inductance of the same magnitude would be cancelled out for every frequency applied. For low power level applications like active receiving antennas, this approach has already been successfully used in the past to achieve improved matching of simple antenna structures over a comparably large bandwidth. We make use of non-Foster circuits, namely negative impedance converters, to compensate the inductive part of two loosely coupled inductors to achieve smaller transfer losses and better impedance matching, which should lead to a decreased transfer signal loss and higher signal to noise ratio. The results of this paper serve as a basis for this development. So far, we achieved almost complete cancellation of the reactive part introduced by the loosely coupled data transfer inductors. Unfortunately, the circuits active device used to form the negative impe
{"title":"Optimization of loosely coupled inductive data transfer systems by non-Foster impedance matching","authors":"C. Schmidt, M. Buchholz, M. Chandra","doi":"10.5194/ars-17-151-2019","DOIUrl":"https://doi.org/10.5194/ars-17-151-2019","url":null,"abstract":"Abstract. Wireless energy transfer is often used in industrial applications to power actors or sensors, for example in rotating applications as replacement for mechanical slip rings. In addition to the energy transfer, we have developed inductively coupled data transfer systems to expand the range of possible applications. The data transfer is accomplished by using loosely coupled coils on both sides of the power transfer system. In pure energy transfer systems, resonant coupling is used, meaning that the power transfer coils are both tuned to a common frequency to compensate the relatively small coupling factor between power transmitter and receiver and to achieve an impedance matching between both sides by compensating the inductive component of the transfer coils. In this case, capacitors can be connected in series or in parallel to the coils, leading to a sharp, narrow band resonance peak in the transfer function. In inductively coupled data transfer systems, this approach is often not useful because not just a pure sine wave has to be transferred but more likely a signal of a certain bandwidth. In one of our applications, a 100 Mbit s−1 Ethernet stream is transferred with an occupied bandwidth of 62.5 MHz. The coil structures used so far in our data transfer applications were intrinsically unmatched to the data transfer systems. Additionally, due to the small coupling factor between the data transfer coils, transfer losses in the range of up to 15 dB or worth had to be accepted. This is especially critical regarding the high noise level in vicinity of the energy transfer system and the cross coupling between the two transfer channels. For passive, lossless circuits, Foster's theorem states that the reactance increases monotonically with frequency. Subsequently, the inductive part of a circuit can just be exactly compensated with a capacitance for one single frequency. In contrast, active circuits like a negative impedance converter (NIC) can be used to achieve a non-Foster behaviour, for example a negative inductance can be realized. In theory, an inductance in series or parallel to a negative inductance of the same magnitude would be cancelled out for every frequency applied. For low power level applications like active receiving antennas, this approach has already been successfully used in the past to achieve improved matching of simple antenna structures over a comparably large bandwidth. We make use of non-Foster circuits, namely negative impedance converters, to compensate the inductive part of two loosely coupled inductors to achieve smaller transfer losses and better impedance matching, which should lead to a decreased transfer signal loss and higher signal to noise ratio. The results of this paper serve as a basis for this development. So far, we achieved almost complete cancellation of the reactive part introduced by the loosely coupled data transfer inductors. Unfortunately, the circuits active device used to form the negative impe","PeriodicalId":45093,"journal":{"name":"Advances in Radio Science","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2019-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49624131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Matthias G. Ehrnsperger, U. Siart, Michael Moosbühler, Emil Daporta, T. Eibert
Abstract. This paper focusses on a transmission line (TL) based model which allows to investigate the impact of multilayered obstructions in the propagating path of a radar signal at different distances and in combination with disturbances. Those disturbances can be water, snow, ice, and foliage at different densities, temperatures, positions, with a given thickness and layer combination. For the evaluation of the detectability of objects, the impulse response of the system can be obtained. Investigations employing state-of-the-art radar hardware confirm the consistency of theoretical and experimental results for 24 and 77 GHz. The analysis in this paper supports testing the specifications for radar systems, before carrier frequency and antenna layout are finally decided. Thereby, the radar system parameters can be adjusted toward employed carrier frequency, bandwidth, required sensitivity, antenna and amplifier gain. Since automotive standards define operational environmental conditions such as temperature, rain rate, and layer thickness, these parameters can be included and adapted. A novel optimisation methodology for radomes is presented which allows to boost the dynamic range by almost 6 dB with presence of a worst-case cover layer of water. The findings can be utilised to properly design radar systems for automotive applications in autonomous driving, in which other vulnerable road users have to be protected under all circumstances.
{"title":"Signal degradation through sediments on safety-critical radar sensors","authors":"Matthias G. Ehrnsperger, U. Siart, Michael Moosbühler, Emil Daporta, T. Eibert","doi":"10.5194/ars-17-91-2019","DOIUrl":"https://doi.org/10.5194/ars-17-91-2019","url":null,"abstract":"Abstract. This paper focusses on a transmission line (TL) based model which allows to\u0000investigate the impact of multilayered obstructions in the propagating path\u0000of a radar signal at different distances and in combination with\u0000disturbances. Those disturbances can be water, snow, ice, and foliage at\u0000different densities, temperatures, positions, with a given thickness and\u0000layer combination. For the evaluation of the detectability of objects, the\u0000impulse response of the system can be obtained. Investigations employing\u0000state-of-the-art radar hardware confirm the consistency of theoretical and\u0000experimental results for 24 and 77 GHz. The analysis in this paper supports\u0000testing the specifications for radar systems, before carrier frequency and\u0000antenna layout are finally decided. Thereby, the radar system parameters can\u0000be adjusted toward employed carrier frequency, bandwidth, required\u0000sensitivity, antenna and amplifier gain. Since automotive standards define\u0000operational environmental conditions such as temperature, rain rate, and\u0000layer thickness, these parameters can be included and adapted. A novel\u0000optimisation methodology for radomes is presented which allows to boost the\u0000dynamic range by almost 6 dB with presence of a worst-case cover layer of\u0000water. The findings can be utilised to properly design radar systems for\u0000automotive applications in autonomous driving, in which other vulnerable road\u0000users have to be protected under all circumstances.\u0000","PeriodicalId":45093,"journal":{"name":"Advances in Radio Science","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2019-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42560331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cornelia Reschka, Sebastian Koj, S. Fisahn, H. Garbe
Abstract. During the assessment of the electromagnetic emissions of wind turbines (WTs), the aspects of measurement uncertainty must be taken into account. Therefore, this work focuses on the measurement uncertainty which arises through distance errors of the measuring positions around a WT. The measurement distance given by the corresponding standard is 30 m with respect to the WT tower. However, this determined distance will always differ e.g. due to unevenness of the surrounding ground, leading to measurement uncertainties. These uncertainties can be estimated with the knowledge of the electromagnetic field distribution. It is assumed in standard measurements, that the electromagnetic field present is a pure transversal electromagnetic field (far field). Simulations of a simplified WT model with a hub height of 100 m shows that this assumption is not effective for the whole frequency range from 150 kHz to 1 GHz. For frequencies below 3 MHz the field distribution is monotonically decreasing with the distance from the WT since it behaves like an electrical small radiator. Whereas for frequencies above 3 MHz, where the investigated model forms an electrical large radiator, the field distribution becomes more complex and the measurement uncertainty of the field strength at the observation point increases. Therefore, this work focuses on investigations where the near field becomes a far field. Based on the simulation results, a method for minimizing the uncertainty contribution caused by distance errors is presented. Therefore, advanced measurement uncertainty during in situ test of WTs can be reduced.
{"title":"Measurement uncertainty caused by distance errors during in situ tests of wind turbines","authors":"Cornelia Reschka, Sebastian Koj, S. Fisahn, H. Garbe","doi":"10.5194/ars-17-19-2019","DOIUrl":"https://doi.org/10.5194/ars-17-19-2019","url":null,"abstract":"Abstract. During the assessment of the electromagnetic emissions of wind turbines\u0000(WTs), the aspects of measurement uncertainty must be taken into account.\u0000Therefore, this work focuses on the measurement uncertainty which arises\u0000through distance errors of the measuring positions around a WT. The measurement distance given by the corresponding standard is 30 m with\u0000respect to the WT tower. However, this determined distance will always\u0000differ e.g. due to unevenness of the surrounding ground, leading to\u0000measurement uncertainties. These uncertainties can be estimated with the\u0000knowledge of the electromagnetic field distribution. It is assumed in\u0000standard measurements, that the electromagnetic field present is a pure\u0000transversal electromagnetic field (far field). Simulations of a simplified\u0000WT model with a hub height of 100 m shows that this assumption is not\u0000effective for the whole frequency range from 150 kHz to 1 GHz. For\u0000frequencies below 3 MHz the field distribution is monotonically decreasing\u0000with the distance from the WT since it behaves like an electrical small\u0000radiator. Whereas for frequencies above 3 MHz, where the investigated model\u0000forms an electrical large radiator, the field distribution becomes more\u0000complex and the measurement uncertainty of the field strength at the\u0000observation point increases. Therefore, this work focuses on investigations\u0000where the near field becomes a far field. Based on the simulation results, a\u0000method for minimizing the uncertainty contribution caused by distance errors\u0000is presented. Therefore, advanced measurement uncertainty during in situ\u0000test of WTs can be reduced.\u0000","PeriodicalId":45093,"journal":{"name":"Advances in Radio Science","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2019-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46566156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. The increasing availability of off-the-shelf high-frequency components makes radar measurement become popular in mainstream industrial applications. We present a cooperative FM radar for strongly reflective environments, being devised for a range of up to approx. 120 m. The target is designed with an unambiguous signature method and satisfies coherence. A prototype is built with commercial semiconductor components that operates in the 24 GHz industrial, scientific and medical band. First experimental results taken in sewage pipes are presented, using the target prototype and a standard FMCW radio station. An overview on four data acquisition procedures is given.
{"title":"Cooperative radar with signature method for unambiguity","authors":"Simon Müller, A. Diewald","doi":"10.5194/ars-17-27-2019","DOIUrl":"https://doi.org/10.5194/ars-17-27-2019","url":null,"abstract":"Abstract. The increasing availability of off-the-shelf high-frequency components makes radar measurement become popular in mainstream industrial applications. We present a cooperative FM radar for strongly reflective environments, being devised for a range of up to approx. 120 m. The target is designed with an unambiguous signature method and satisfies coherence. A prototype is built with commercial semiconductor components that operates in the 24 GHz industrial, scientific and medical band. First experimental results taken in sewage pipes are presented, using the target prototype and a standard FMCW radio station. An overview on four data acquisition procedures is given.\u0000","PeriodicalId":45093,"journal":{"name":"Advances in Radio Science","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2019-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49547972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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