Pub Date : 2018-04-01DOI: 10.1109/WMCAS.2018.8400645
Avi Sulimarski, O. Avraham, J. Stein, D. Lipshitz
This paper presents a novel technique, based on digital signal processing, for nonlinear modeling and pre-distortion of multiple parallel power amplifiers in a beam-forming transmitter. By jointly estimating a mutual pre-distortion function that effectively compensates for the distortions experienced in the entire transmission system, the proposed method optimizes performance for a single digital pre-distortion system. This method exhibits superior performance of up to 5dB in EVM and PSD in transmitter KPI compared to the standard method, where the multiple PAs are pre-distorted using digital pre-distortion derived from a single arbitrary PA.
{"title":"Polynomial memory pre distortion for 5G wireless systems with multiple power amplifiers","authors":"Avi Sulimarski, O. Avraham, J. Stein, D. Lipshitz","doi":"10.1109/WMCAS.2018.8400645","DOIUrl":"https://doi.org/10.1109/WMCAS.2018.8400645","url":null,"abstract":"This paper presents a novel technique, based on digital signal processing, for nonlinear modeling and pre-distortion of multiple parallel power amplifiers in a beam-forming transmitter. By jointly estimating a mutual pre-distortion function that effectively compensates for the distortions experienced in the entire transmission system, the proposed method optimizes performance for a single digital pre-distortion system. This method exhibits superior performance of up to 5dB in EVM and PSD in transmitter KPI compared to the standard method, where the multiple PAs are pre-distorted using digital pre-distortion derived from a single arbitrary PA.","PeriodicalId":254840,"journal":{"name":"2018 Texas Symposium on Wireless and Microwave Circuits and Systems (WMCS)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132578917","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}
Pub Date : 2018-04-01DOI: 10.1109/WMCAS.2018.8400631
Amirreza Ghadimi Avval, S. El-Ghazaly
The recent upsurge in wireless communications demands devices working at higher frequencies with higher output densities. In general, wide-bandgap materials seem to be the reliable choice for these applications, specifically GaN HEMT that has shown great advantage over its previous counterparts. A holistic optimization technique is proposed to define the stages that a high frequency, high power device is designed. An issue with the thermal conductivity of the substrates for these devices is also addressed and a fabrication technique is proposed to solve it.
{"title":"Holistic optimization technique for solving low thermal conductivity of sapphire substrates in high frequency devices","authors":"Amirreza Ghadimi Avval, S. El-Ghazaly","doi":"10.1109/WMCAS.2018.8400631","DOIUrl":"https://doi.org/10.1109/WMCAS.2018.8400631","url":null,"abstract":"The recent upsurge in wireless communications demands devices working at higher frequencies with higher output densities. In general, wide-bandgap materials seem to be the reliable choice for these applications, specifically GaN HEMT that has shown great advantage over its previous counterparts. A holistic optimization technique is proposed to define the stages that a high frequency, high power device is designed. An issue with the thermal conductivity of the substrates for these devices is also addressed and a fabrication technique is proposed to solve it.","PeriodicalId":254840,"journal":{"name":"2018 Texas Symposium on Wireless and Microwave Circuits and Systems (WMCS)","volume":"169 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116317406","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}
Pub Date : 2018-04-01DOI: 10.1109/WMCAS.2018.8400646
Mitchell J. Grabner, Xinrong Li, Shengli Fu
Space-time block codes which follow the perfect coding principle are a new class of full-rate linear-dispersion codes which are also fully diverse. These codes are therefore optimal in terms of the diversity-multiplexing tradeoff put forward by Zheng and Tse. However, this condition is dependent on the decoding method also being optimal, hence some form of maximum-likelihood decoding should be employed. For large multiple-input multiple-output arrays where latency and throughput are the limiting factors it is more practical to use linear equalization based receivers. In this paper we explore the effects of linear minimum mean-square error (MMSE) based decoding with and without optimal ordering and symbol cancellation (BLAST) on various perfect space-time block codes up to 8 × 8 arrays both with and without channel coding for bits per channel-use up to 48. These results are compared to equivalent spatial multiplexing systems using the same linear de-multiplexing used in many state-of-the-art commercial systems.
{"title":"Performance of perfect space-time codes under linear MMSE equalization and BLAST based decoding for large data rates","authors":"Mitchell J. Grabner, Xinrong Li, Shengli Fu","doi":"10.1109/WMCAS.2018.8400646","DOIUrl":"https://doi.org/10.1109/WMCAS.2018.8400646","url":null,"abstract":"Space-time block codes which follow the perfect coding principle are a new class of full-rate linear-dispersion codes which are also fully diverse. These codes are therefore optimal in terms of the diversity-multiplexing tradeoff put forward by Zheng and Tse. However, this condition is dependent on the decoding method also being optimal, hence some form of maximum-likelihood decoding should be employed. For large multiple-input multiple-output arrays where latency and throughput are the limiting factors it is more practical to use linear equalization based receivers. In this paper we explore the effects of linear minimum mean-square error (MMSE) based decoding with and without optimal ordering and symbol cancellation (BLAST) on various perfect space-time block codes up to 8 × 8 arrays both with and without channel coding for bits per channel-use up to 48. These results are compared to equivalent spatial multiplexing systems using the same linear de-multiplexing used in many state-of-the-art commercial systems.","PeriodicalId":254840,"journal":{"name":"2018 Texas Symposium on Wireless and Microwave Circuits and Systems (WMCS)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116997001","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}
Pub Date : 2018-04-01DOI: 10.1109/WMCAS.2018.8400643
H. Madjar
The antenna limits imposed in America and Europe are compared with the patterns in an ITU-R Recommendation. As most of RF interference emanates from the sidelobes of the transmitting antennas and enters through those of the receiving antennas, the regulation and standardization of antenna patterns is essential to optimize RF spectrum reuse. Since there are no regional standards in Asia and Africa for directional point-to-point antennas, the reference envelopes defined by the ITU, the European-based ETSI and the USA-based FCC are adopted globally. Depicting these limits, next to measured antenna patterns from two different suppliers, reveals that the ETSI limits are more restrictive than those of the FCC. New theoretical evidence is provided for the 2018 revision of the ITU Recommendation. Proposals are provided to tighten FCC limits and to loosen those of ETSI.
{"title":"Regulating and standardizing directive antenna patterns to improve coexistence","authors":"H. Madjar","doi":"10.1109/WMCAS.2018.8400643","DOIUrl":"https://doi.org/10.1109/WMCAS.2018.8400643","url":null,"abstract":"The antenna limits imposed in America and Europe are compared with the patterns in an ITU-R Recommendation. As most of RF interference emanates from the sidelobes of the transmitting antennas and enters through those of the receiving antennas, the regulation and standardization of antenna patterns is essential to optimize RF spectrum reuse. Since there are no regional standards in Asia and Africa for directional point-to-point antennas, the reference envelopes defined by the ITU, the European-based ETSI and the USA-based FCC are adopted globally. Depicting these limits, next to measured antenna patterns from two different suppliers, reveals that the ETSI limits are more restrictive than those of the FCC. New theoretical evidence is provided for the 2018 revision of the ITU Recommendation. Proposals are provided to tighten FCC limits and to loosen those of ETSI.","PeriodicalId":254840,"journal":{"name":"2018 Texas Symposium on Wireless and Microwave Circuits and Systems (WMCS)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134337927","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}
Pub Date : 2018-04-01DOI: 10.1109/WMCAS.2018.8400629
Drew G. Bresnahan, Yang Li
Wireless Body Area Network (WBAN) technology holds great potential for many applications such as remote healthcare monitoring and personal activity tracking. A vector network analyzer can be used to measure on-body channel changes due to different activities, but they are much too costly and bulky for most WBAN applications. Small, wearable, affordable sensors must be developed for practical WBAN usage. This paper investigates two methods for replacing the network analyzer from an on-body wave propagation measurement setup.
{"title":"Measurement of around-body creeping waves using wearable sensor modules","authors":"Drew G. Bresnahan, Yang Li","doi":"10.1109/WMCAS.2018.8400629","DOIUrl":"https://doi.org/10.1109/WMCAS.2018.8400629","url":null,"abstract":"Wireless Body Area Network (WBAN) technology holds great potential for many applications such as remote healthcare monitoring and personal activity tracking. A vector network analyzer can be used to measure on-body channel changes due to different activities, but they are much too costly and bulky for most WBAN applications. Small, wearable, affordable sensors must be developed for practical WBAN usage. This paper investigates two methods for replacing the network analyzer from an on-body wave propagation measurement setup.","PeriodicalId":254840,"journal":{"name":"2018 Texas Symposium on Wireless and Microwave Circuits and Systems (WMCS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129461587","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}
Pub Date : 2018-04-01DOI: 10.1109/WMCAS.2018.8400639
Jeremy Hershberger, T. Pratt, Robert D. Kossler
A dual-polarized radar is capable of characterizing a time-varying target and extracting its vibrational spectrum. This work details the concepts of that process in the context of remotely observing the health of multiple electric pumps at a local industrial plant. The efficacy of the approach is demonstrated through a small-scale experiment sensing different vibration signatures of an electric motor with a dual-polarized radar system.
{"title":"Non-contact rotating machine health status via dual-polarized radar","authors":"Jeremy Hershberger, T. Pratt, Robert D. Kossler","doi":"10.1109/WMCAS.2018.8400639","DOIUrl":"https://doi.org/10.1109/WMCAS.2018.8400639","url":null,"abstract":"A dual-polarized radar is capable of characterizing a time-varying target and extracting its vibrational spectrum. This work details the concepts of that process in the context of remotely observing the health of multiple electric pumps at a local industrial plant. The efficacy of the approach is demonstrated through a small-scale experiment sensing different vibration signatures of an electric motor with a dual-polarized radar system.","PeriodicalId":254840,"journal":{"name":"2018 Texas Symposium on Wireless and Microwave Circuits and Systems (WMCS)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115877019","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}
Pub Date : 2018-04-01DOI: 10.1109/WMCAS.2018.8400637
V. Singh, R. Gharpurey
A frequency-folded analog-to-digital converter (FF-ADC) simultaneously channelizes and digitizes a broadband input signal, while using a single LO. The broadband signal is downconverted and aliased in polyphase signal paths. The aliased signals are band-limited and are individually digitized using low-frequency sub-band ADCs. Channelization is performed using harmonic rejection after digitization. In this work an FF-ADC architecture is described wherein the sub-bands can be individually attenuated before the ADCs. This helps to relax the dynamic range requirement of the ADCs in the presence of a large variation over frequency in power spectral density in the broadband input signal. It is also shown that sub-band rejection better than 15 dB can be achieved for selected bands, without calibration, while the rest of the sub-bands are downconverted with equal gain. The approach is verified in simulation.
{"title":"Channelized front-ends for broadband signal processing with sub-band dynamic range control","authors":"V. Singh, R. Gharpurey","doi":"10.1109/WMCAS.2018.8400637","DOIUrl":"https://doi.org/10.1109/WMCAS.2018.8400637","url":null,"abstract":"A frequency-folded analog-to-digital converter (FF-ADC) simultaneously channelizes and digitizes a broadband input signal, while using a single LO. The broadband signal is downconverted and aliased in polyphase signal paths. The aliased signals are band-limited and are individually digitized using low-frequency sub-band ADCs. Channelization is performed using harmonic rejection after digitization. In this work an FF-ADC architecture is described wherein the sub-bands can be individually attenuated before the ADCs. This helps to relax the dynamic range requirement of the ADCs in the presence of a large variation over frequency in power spectral density in the broadband input signal. It is also shown that sub-band rejection better than 15 dB can be achieved for selected bands, without calibration, while the rest of the sub-bands are downconverted with equal gain. The approach is verified in simulation.","PeriodicalId":254840,"journal":{"name":"2018 Texas Symposium on Wireless and Microwave Circuits and Systems (WMCS)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128696227","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}
Pub Date : 2018-04-01DOI: 10.1109/WMCAS.2018.8400653
Yibo Wang, Dagang Wu, Ji Chen
An efficient dielectric property measurement system is introduced in this paper. In the proposed measurement system, a parallel-disk sample holder with a new designed substrate is employed, which enables measuring the anisotropic input impedance of rock samples by rotating testing samples inside the holder. Moreover, a full wave simulation method is utilized to numerically calculate anisotropic input impedances of rock samples using anisotropic permittivity and conductivity given in a wide range. Anisotropic dielectric properties of a rock sample can then be estimated by comparing and correlating its experimental results and pre-computed simulation results. Additional look-up tables can be numerically computed for different substrate materials. Based on measured anisotropic input impedance and known material property of the substrate, dielectric properties of a certain rock sample can be computed from the corresponding look-up table.
{"title":"A comprehensive system of measuring anisotropic dielectric properties of rock samples","authors":"Yibo Wang, Dagang Wu, Ji Chen","doi":"10.1109/WMCAS.2018.8400653","DOIUrl":"https://doi.org/10.1109/WMCAS.2018.8400653","url":null,"abstract":"An efficient dielectric property measurement system is introduced in this paper. In the proposed measurement system, a parallel-disk sample holder with a new designed substrate is employed, which enables measuring the anisotropic input impedance of rock samples by rotating testing samples inside the holder. Moreover, a full wave simulation method is utilized to numerically calculate anisotropic input impedances of rock samples using anisotropic permittivity and conductivity given in a wide range. Anisotropic dielectric properties of a rock sample can then be estimated by comparing and correlating its experimental results and pre-computed simulation results. Additional look-up tables can be numerically computed for different substrate materials. Based on measured anisotropic input impedance and known material property of the substrate, dielectric properties of a certain rock sample can be computed from the corresponding look-up table.","PeriodicalId":254840,"journal":{"name":"2018 Texas Symposium on Wireless and Microwave Circuits and Systems (WMCS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129972659","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}
Pub Date : 2018-04-01DOI: 10.1109/WMCAS.2018.8400650
K. Tran, R. Henderson
In this paper we propose a new technique to use load-pull data for broadband power amplifier design as an alternative to the simplified real frequency technique (SRFT). Like SRFT the bounded performance (BP) technique optimizes a matching network over many discrete frequencies that span the operating bandwidth. Unlike SRFT, BP optimizes the match over a Smith chart area defined by design specifications and load-pull data. From this area, we deduce a simple cost function for optimizing the matching network. The technique alleviates the problem with broadband point matching, where a physically realizable matching network cannot trace the trajectory of the optimal reflection coefficients of a power transistor over a wide frequency range. It also includes design specifications into the formulation of the optimization cost function, thus ensuring the design will meet the required performance. Using a 15-W Qorvo GaN HEMT plastic device and BP technique, we designed and built a C-band 4–5 GHz amplifier. We measured on average 18-W output power and 56% drain efficiency from 5 first-pass amplifiers. Results from testing 1 amplifier with 20-MHz LTE signal and without pre-distortion showed maximum adjacent channel power ratio of −38.5 dBc and maximum alternate power channel ratio of −49 dBc at up to 32.5 dBm average output power, or 9 dB back-off from saturation.
{"title":"Bounded performance technique for broadband amplifier design","authors":"K. Tran, R. Henderson","doi":"10.1109/WMCAS.2018.8400650","DOIUrl":"https://doi.org/10.1109/WMCAS.2018.8400650","url":null,"abstract":"In this paper we propose a new technique to use load-pull data for broadband power amplifier design as an alternative to the simplified real frequency technique (SRFT). Like SRFT the bounded performance (BP) technique optimizes a matching network over many discrete frequencies that span the operating bandwidth. Unlike SRFT, BP optimizes the match over a Smith chart area defined by design specifications and load-pull data. From this area, we deduce a simple cost function for optimizing the matching network. The technique alleviates the problem with broadband point matching, where a physically realizable matching network cannot trace the trajectory of the optimal reflection coefficients of a power transistor over a wide frequency range. It also includes design specifications into the formulation of the optimization cost function, thus ensuring the design will meet the required performance. Using a 15-W Qorvo GaN HEMT plastic device and BP technique, we designed and built a C-band 4–5 GHz amplifier. We measured on average 18-W output power and 56% drain efficiency from 5 first-pass amplifiers. Results from testing 1 amplifier with 20-MHz LTE signal and without pre-distortion showed maximum adjacent channel power ratio of −38.5 dBc and maximum alternate power channel ratio of −49 dBc at up to 32.5 dBm average output power, or 9 dB back-off from saturation.","PeriodicalId":254840,"journal":{"name":"2018 Texas Symposium on Wireless and Microwave Circuits and Systems (WMCS)","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125101507","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}
Pub Date : 2018-04-01DOI: 10.1109/WMCAS.2018.8400649
R. Mir, W. Frensley
For an N-terminal device, we can define N dimensionless functions of position by differentiating the electrostatic potential with respect to each of the terminal voltages. At any point in the device these functions sum to unity. They provide a natural generalization of the Shockley-Ramo theorem relating the motion of charges within the device to the terminal currents, and also tell us how the electric field lines originating from an extra charge placed into the device are partitioned among the different terminals. They provide a microscopic indicator of amplification: values of these functions can be negative or greater than unity only in active devices. An examination of some textbook device examples demonstrates how the information encoded in these functions may be interpreted, and shows how the effects that they quantify have been repeatedly invoked in an intuitive fashion in past device analyses. We also illustrate the application of these functions to a current problem: understanding the current-control characteristics of short-channel FinFET devices.
{"title":"Quantifying the local influence of terminal voltages within an electron device","authors":"R. Mir, W. Frensley","doi":"10.1109/WMCAS.2018.8400649","DOIUrl":"https://doi.org/10.1109/WMCAS.2018.8400649","url":null,"abstract":"For an N-terminal device, we can define N dimensionless functions of position by differentiating the electrostatic potential with respect to each of the terminal voltages. At any point in the device these functions sum to unity. They provide a natural generalization of the Shockley-Ramo theorem relating the motion of charges within the device to the terminal currents, and also tell us how the electric field lines originating from an extra charge placed into the device are partitioned among the different terminals. They provide a microscopic indicator of amplification: values of these functions can be negative or greater than unity only in active devices. An examination of some textbook device examples demonstrates how the information encoded in these functions may be interpreted, and shows how the effects that they quantify have been repeatedly invoked in an intuitive fashion in past device analyses. We also illustrate the application of these functions to a current problem: understanding the current-control characteristics of short-channel FinFET devices.","PeriodicalId":254840,"journal":{"name":"2018 Texas Symposium on Wireless and Microwave Circuits and Systems (WMCS)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123993019","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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