S. Fisahn, Christian Siebauer, J. Ringkamp, K. Dehning, S. Zimmermann, J. Langejürgen
Measuring respiratory parameters like the breathing frequency or the tidal volume is essential in intensive care to ensure an optimal and lung protecting ventilation. A common practice in artificial ventilation of sensitive patients like infants or neonates is the use of uncuffed endotracheal tubes in combination with continuous positive airway pressure (CPAP). This comes with the disadvantage of an unknown leakage making it difficult to detect spontaneous breathing or to measure the tidal volume reliable. A novel non-obstructive method to determine respiratory parameters as well as dynamic changes of thoracic parameters has recently been presented and uses a pair of coupled UHF (ultra high frequency) antennae. In this paper, a respective setup is investigated numerically using finite difference time domain method and experimentally using an artificial lung phantom. Both approaches show that the investigated method seems capable of allowing a contactless triggering to synchronize natural and artificial breathing. The results are compared to derive a better understanding of influencing factors and opportunities for an optimisation.
{"title":"Respiration parameter determination with non-obstructive methods","authors":"S. Fisahn, Christian Siebauer, J. Ringkamp, K. Dehning, S. Zimmermann, J. Langejürgen","doi":"10.5194/ars-18-89-2020","DOIUrl":"https://doi.org/10.5194/ars-18-89-2020","url":null,"abstract":"Measuring respiratory parameters like the breathing frequency or the tidal volume is essential in intensive care to ensure an optimal and lung protecting ventilation. A common practice in artificial ventilation of sensitive patients like infants or neonates is the use of uncuffed endotracheal tubes in combination with continuous positive airway pressure (CPAP). This comes with the disadvantage of an unknown leakage making it difficult to detect spontaneous breathing or to measure the tidal volume reliable. A novel non-obstructive method to determine respiratory parameters as well as dynamic changes of thoracic parameters has recently been presented and uses a pair of coupled UHF (ultra high frequency) antennae. In this paper, a respective setup is investigated numerically using finite difference time domain method and experimentally using an artificial lung phantom. Both approaches show that the investigated method seems capable of allowing a contactless triggering to synchronize natural and artificial breathing. The results are compared to derive a better understanding of influencing factors and opportunities for an optimisation.","PeriodicalId":45093,"journal":{"name":"Advances in Radio Science","volume":"18 1","pages":"89-95"},"PeriodicalIF":0.4,"publicationDate":"2020-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48126865","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":"1 1","pages":""},"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":" ","pages":""},"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":" ","pages":""},"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}
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":" ","pages":""},"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}
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":" ","pages":""},"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. 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":" ","pages":""},"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}
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":" ","pages":""},"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. 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":" ","pages":""},"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}
Abstract. A substrate integrated waveguide (SIW) with transverse slots on the top plane can be used to design an effective leaky-wave antenna with good frequency beam-scanning and platform integration capability. For a main beam near end-fire, the phase constant of the radiating wave must be near to the free space wavenumber or slightly larger. In this context, the modified Hansen-Woodyard condition gives an optimum phase constant to maximize the directivity at end-fire. For the analysis of the wave propagation we have implemented a modal analysis for rectangular waveguides with transverse slots. Near end-fire, three types of modal solutions exists, a leaky improper mode, a surface wave mode and a proper waveguide mode. The leaky mode can reach phase constants larger than the free space wavenumber to fulfill the Hansen-Woodyard condition, but loses strongly its physical significance in this slow wave region, thus the excitation of the leaky-wave becomes negligible there, whereas the proper waveguide mode is dominant but exhibits only a negligible radiation loss leading to a strong drop of the antenna efficiency. Therefore, the optimum efficiency of 86 % for maximizing the gain as proposed in the literature cannot be reached with this kind of leaky wave antenna. But it will be shown in this contribution by analyzing antenna structures with finite aperture lengths, that the efficiency can reach nearly 100 % if the phase constant of the leaky-wave meets exactly the free space wavenumber (ordinary end-fire condition) and the aperture length is adjusted with regard to the attenuation constant of the leaky-wave from the modal analysis. For a given aperture length, a procedure is outlined to adjust the attenuation constant in several steps at the desired ordinary end-fire frequency to reach maximum gain and efficiency.
{"title":"Design of leaky-wave antennas with transverse slots for end-fire radiation with optimized radiation efficiency","authors":"T. Vaupel, Claudius Löcker","doi":"10.5194/ars-17-71-2019","DOIUrl":"https://doi.org/10.5194/ars-17-71-2019","url":null,"abstract":"Abstract. A substrate integrated waveguide (SIW) with transverse\u0000slots on the top plane can be used to design an effective leaky-wave antenna\u0000with good frequency beam-scanning and platform integration capability. For a\u0000main beam near end-fire, the phase constant of the radiating wave must be\u0000near to the free space wavenumber or slightly larger. In this context, the\u0000modified Hansen-Woodyard condition gives an optimum phase constant to\u0000maximize the directivity at end-fire. For the analysis of the wave\u0000propagation we have implemented a modal analysis for rectangular waveguides\u0000with transverse slots. Near end-fire, three types of modal solutions exists,\u0000a leaky improper mode, a surface wave mode and a proper waveguide mode. The\u0000leaky mode can reach phase constants larger than the free space wavenumber\u0000to fulfill the Hansen-Woodyard condition, but loses strongly its physical\u0000significance in this slow wave region, thus the excitation of the leaky-wave\u0000becomes negligible there, whereas the proper waveguide mode is dominant but\u0000exhibits only a negligible radiation loss leading to a strong drop of the\u0000antenna efficiency. Therefore, the optimum efficiency of 86 % for\u0000maximizing the gain as proposed in the literature cannot be reached with\u0000this kind of leaky wave antenna. But it will be shown in this contribution by analyzing antenna structures\u0000with finite aperture lengths, that the efficiency can reach nearly 100 %\u0000if the phase constant of the leaky-wave meets exactly the free space\u0000wavenumber (ordinary end-fire condition) and the aperture length is adjusted\u0000with regard to the attenuation constant of the leaky-wave from the modal\u0000analysis. For a given aperture length, a procedure is outlined to adjust the\u0000attenuation constant in several steps at the desired ordinary end-fire\u0000frequency to reach maximum gain and efficiency.\u0000","PeriodicalId":45093,"journal":{"name":"Advances in Radio Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44272536","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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