Pub Date : 2008-06-15DOI: 10.1109/MWSYM.2008.4633046
Hong Yin, Danqiong Hou, G. Bilbro, R. Trew
HFETs fabricated with nitride-based wide bandgap materials are capable of producing high RF output power and are promising for the next generation radar and wireless communication systems. To take full advantage of this new kind of device, large-signal models suitable for use in commercial microwave circuit simulators are desirable, but existing models can only interpolate or fit data that has been measured from previously fabricated devices. In this study, a new physics-based large-signal model for AlGaN/GaN HFETs is introduced that can predict the large-signal performance of an HFET from its design parameters. It couples a compact physics-based DC module with a harmonic balance RF module. This new model is shown to agree with both DC and RF experimental data without any adjustable fitting parameters for the device. The DC IV and transconductance curves predicted by this new model also agree with those generated by a commercial 2D simulator.
{"title":"Harmonic balance simulation of a new physics based model of the AlGaN/GaN HFET","authors":"Hong Yin, Danqiong Hou, G. Bilbro, R. Trew","doi":"10.1109/MWSYM.2008.4633046","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633046","url":null,"abstract":"HFETs fabricated with nitride-based wide bandgap materials are capable of producing high RF output power and are promising for the next generation radar and wireless communication systems. To take full advantage of this new kind of device, large-signal models suitable for use in commercial microwave circuit simulators are desirable, but existing models can only interpolate or fit data that has been measured from previously fabricated devices. In this study, a new physics-based large-signal model for AlGaN/GaN HFETs is introduced that can predict the large-signal performance of an HFET from its design parameters. It couples a compact physics-based DC module with a harmonic balance RF module. This new model is shown to agree with both DC and RF experimental data without any adjustable fitting parameters for the device. The DC IV and transconductance curves predicted by this new model also agree with those generated by a commercial 2D simulator.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"255 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123959660","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 : 2008-06-15DOI: 10.1109/MWSYM.2008.4633142
Wenquan Che, Cuixia Li, P. Russer, Y. Chow
To improve the bandwidth of the SIW, a planar ridged substrate-integrated waveguide (RSIW) with a center line of cylindrical posts is proposed. Theoretical design formulas are derived. The bandwidth is defined as between the cutoffs of TE10 and TE20 modes of the RSIW. The modes are made equivalent to those of a transmission line cavity, across the transverse plane, and the cavity is loaded by a ridge of capacitive posts. Good agreements are observed between the theoretical formulas and numerical simulations. A 37% bandwidth enhancement is achieved; in fact, with structures added to increase the post capacitance, still higher bandwidth enhancement is possible.
{"title":"Propagation and band broadening effect of planar integrated ridged waveguide in multilayer dielectric substrates","authors":"Wenquan Che, Cuixia Li, P. Russer, Y. Chow","doi":"10.1109/MWSYM.2008.4633142","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633142","url":null,"abstract":"To improve the bandwidth of the SIW, a planar ridged substrate-integrated waveguide (RSIW) with a center line of cylindrical posts is proposed. Theoretical design formulas are derived. The bandwidth is defined as between the cutoffs of TE10 and TE20 modes of the RSIW. The modes are made equivalent to those of a transmission line cavity, across the transverse plane, and the cavity is loaded by a ridge of capacitive posts. Good agreements are observed between the theoretical formulas and numerical simulations. A 37% bandwidth enhancement is achieved; in fact, with structures added to increase the post capacitance, still higher bandwidth enhancement is possible.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128225741","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 : 2008-06-15DOI: 10.1109/MWSYM.2008.4633175
C. Wagner, R. Feger, A. Haderer, A. Fischer, A. Stelzer, H. Jager
A digital phase-locked synthesizer for application in a 77-GHz frequency modulated continuous wave (FMCW) radar is presented. It consists of a digital phase discriminator, a digital loop filter, highpass modulation, and predistortion of the VCO tuning characteristic. An additional feature is the ability to store the previous phase errors for iterative adaptation of the loop filter coefficients and the highpass modulation parameter. A radar system has been built to compare the proposed digital synthesizer to an offset-loop based one in actual radar measurements.
{"title":"A 77-GHz FMCW radar using a digital phase-locked synthesizer","authors":"C. Wagner, R. Feger, A. Haderer, A. Fischer, A. Stelzer, H. Jager","doi":"10.1109/MWSYM.2008.4633175","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633175","url":null,"abstract":"A digital phase-locked synthesizer for application in a 77-GHz frequency modulated continuous wave (FMCW) radar is presented. It consists of a digital phase discriminator, a digital loop filter, highpass modulation, and predistortion of the VCO tuning characteristic. An additional feature is the ability to store the previous phase errors for iterative adaptation of the loop filter coefficients and the highpass modulation parameter. A radar system has been built to compare the proposed digital synthesizer to an offset-loop based one in actual radar measurements.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"99 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128006568","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 : 2008-06-15DOI: 10.1109/MWSYM.2008.4633068
Ming Xiao, P. Gardner
Two novel injection techniques reduce adjacent channel power ratio (ACPR) in a nonlinear power amplifier (PA). The first injects two ‘brick-wall’ signals covering the adjacent channel bandwidths. All the injected sub-frequencies have the same amplitude but different phases. Tuning these phases, we plot the output signal to determine the appropriate sub-frequency amplitudes and phases to reduce ACPR. The second technique injects cubic products of the original signals, covering the adjacent channels. Both techniques, considered in theory and practice, can reduce spectral regrowth by nearly 30dB. The first is conceptually simple while the second is more practical for embedding into a predistorter.
{"title":"Digital baseband injection techniques to reduce spectral regrowth in power amplifier","authors":"Ming Xiao, P. Gardner","doi":"10.1109/MWSYM.2008.4633068","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633068","url":null,"abstract":"Two novel injection techniques reduce adjacent channel power ratio (ACPR) in a nonlinear power amplifier (PA). The first injects two ‘brick-wall’ signals covering the adjacent channel bandwidths. All the injected sub-frequencies have the same amplitude but different phases. Tuning these phases, we plot the output signal to determine the appropriate sub-frequency amplitudes and phases to reduce ACPR. The second technique injects cubic products of the original signals, covering the adjacent channels. Both techniques, considered in theory and practice, can reduce spectral regrowth by nearly 30dB. The first is conceptually simple while the second is more practical for embedding into a predistorter.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129432203","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 : 2008-06-15DOI: 10.1109/MWSYM.2008.4633032
Joshua L. Wilson, Cheng Wang, Songnan Yang, A. Fathy, Yoon W. Kang
A long-stencil fourth order finite difference method over a Yee-grid is developed to solve Maxwell’s equations. The different variables are located at staggered mesh points, and a symmetric image formula is introduced near the boundary. The introduction of these symmetric ghost grid points assures the stability of the boundary extrapolation, and in turn a complete set of purely imaginary eigenvalues are given for the fourth-order discrete curl operators for both electric and magnetic fields. Subsequently, the four-stage Jameson method integrator constrained by a pre-determined time step is utilized to produce a stable full fourth order accuracy in both time and space. The accuracy of the developed numerical scheme has been validated by comparing its results to the closed form solutions for a rectangular cavity.
{"title":"An accurate and stable fourth order finite difference time domain method","authors":"Joshua L. Wilson, Cheng Wang, Songnan Yang, A. Fathy, Yoon W. Kang","doi":"10.1109/MWSYM.2008.4633032","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633032","url":null,"abstract":"A long-stencil fourth order finite difference method over a Yee-grid is developed to solve Maxwell’s equations. The different variables are located at staggered mesh points, and a symmetric image formula is introduced near the boundary. The introduction of these symmetric ghost grid points assures the stability of the boundary extrapolation, and in turn a complete set of purely imaginary eigenvalues are given for the fourth-order discrete curl operators for both electric and magnetic fields. Subsequently, the four-stage Jameson method integrator constrained by a pre-determined time step is utilized to produce a stable full fourth order accuracy in both time and space. The accuracy of the developed numerical scheme has been validated by comparing its results to the closed form solutions for a rectangular cavity.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129739839","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 : 2008-06-15DOI: 10.1109/MWSYM.2008.4633119
R. Feger, A. Haderer, Stefan Dipl.-Ing. Schuster, S. Scheiblhofer, A. Stelzer
The measurement of different target parameters using radar systems has been an active research area for the last decades. Particularly target angle measurement is a very demanding topic, because obtaining good measurement results often goes hand in hand with extensive hardware effort. Especially for sensors used in the mass market, e.g. in automotive applications like adaptive cruise control this may be prohibitive. Therefore we address target localization using a compact frequency-modulated continuous-wave (FMCW) radar sensor. The angular measurement results are improved compared to standard beamforming methods using an adaptive beamforming approach. This approach will be applied to the FMCW principle in a way that allows the use of well known methods for the determination of other target parameters like range or velocity. The applicability of the developed theory will be shown on different measurement scenarios using a 24-GHz prototype radar system.
{"title":"A four channel 24-GHz FMCW radar sensor with two-dimensional target localization capabilities","authors":"R. Feger, A. Haderer, Stefan Dipl.-Ing. Schuster, S. Scheiblhofer, A. Stelzer","doi":"10.1109/MWSYM.2008.4633119","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633119","url":null,"abstract":"The measurement of different target parameters using radar systems has been an active research area for the last decades. Particularly target angle measurement is a very demanding topic, because obtaining good measurement results often goes hand in hand with extensive hardware effort. Especially for sensors used in the mass market, e.g. in automotive applications like adaptive cruise control this may be prohibitive. Therefore we address target localization using a compact frequency-modulated continuous-wave (FMCW) radar sensor. The angular measurement results are improved compared to standard beamforming methods using an adaptive beamforming approach. This approach will be applied to the FMCW principle in a way that allows the use of well known methods for the determination of other target parameters like range or velocity. The applicability of the developed theory will be shown on different measurement scenarios using a 24-GHz prototype radar system.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130279692","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 : 2008-06-15DOI: 10.1109/MWSYM.2008.4633053
S. Woodington, T. Williams, H. Qi, D. Williams, L. Pattison, A. Patterson, J. Lees, J. Benedikt, P. Tasker
A solution allowing for the rapid, cost effective and accurate extraction of nonlinear Direct Waveform Look-Up table (DWLU) based behavioral models is presented in this paper. The behavioral model extracted is a reformulation of the PHD model, now defined about a non 50-Ohm reference impedance, enabling it to accurately predict load-pull contours. The technique exploits a simple active and passive load-pull architecture enabling a numerical integration solution for model coefficient extraction that necessitates only varying the phase of the input stimulus during measurement. This solution dramatically speeds up the behavioral model coefficient extraction process, enabling ‘real time’ access to critical device behavior. It ensures that only a minimum, optimized set of load-pull measurements are performed. The technique is demonstrated on a Mimix Broadband Gas 8×2×30um 0.5W HBT.
{"title":"A novel measurement based method enabling rapid extraction of a RF Waveform Look-Up table based behavioral model","authors":"S. Woodington, T. Williams, H. Qi, D. Williams, L. Pattison, A. Patterson, J. Lees, J. Benedikt, P. Tasker","doi":"10.1109/MWSYM.2008.4633053","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633053","url":null,"abstract":"A solution allowing for the rapid, cost effective and accurate extraction of nonlinear Direct Waveform Look-Up table (DWLU) based behavioral models is presented in this paper. The behavioral model extracted is a reformulation of the PHD model, now defined about a non 50-Ohm reference impedance, enabling it to accurately predict load-pull contours. The technique exploits a simple active and passive load-pull architecture enabling a numerical integration solution for model coefficient extraction that necessitates only varying the phase of the input stimulus during measurement. This solution dramatically speeds up the behavioral model coefficient extraction process, enabling ‘real time’ access to critical device behavior. It ensures that only a minimum, optimized set of load-pull measurements are performed. The technique is demonstrated on a Mimix Broadband Gas 8×2×30um 0.5W HBT.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130932124","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 : 2008-06-15DOI: 10.1109/MWSYM.2008.4632999
J. Rayas-Sánchez, V. Gutiérrez-Ayala
We propose in this work a general procedure to efficient EM-based design of single-layer SIW interconnects, including their transitions to microstrip lines. Our starting point is developed by exploiting available empirical knowledge for SIW. We propose an efficient SIW surrogate model for direct EM design optimization in two stages: first optimizing the SIW width to achieve the specified low cutoff frequency, followed by the transition optimization to reduce reflections and extend the dominant mode bandwidth. Our procedure is illustrated by designing a SIW interconnect on a standard FR4-based substrate.
{"title":"A general EM-based design procedure for single-layer substrate integrated waveguide interconnects with microstrip transitions","authors":"J. Rayas-Sánchez, V. Gutiérrez-Ayala","doi":"10.1109/MWSYM.2008.4632999","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4632999","url":null,"abstract":"We propose in this work a general procedure to efficient EM-based design of single-layer SIW interconnects, including their transitions to microstrip lines. Our starting point is developed by exploiting available empirical knowledge for SIW. We propose an efficient SIW surrogate model for direct EM design optimization in two stages: first optimizing the SIW width to achieve the specified low cutoff frequency, followed by the transition optimization to reduce reflections and extend the dominant mode bandwidth. Our procedure is illustrated by designing a SIW interconnect on a standard FR4-based substrate.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131164319","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 : 2008-06-15DOI: 10.1109/MWSYM.2008.4633195
M. Koochakzadeh, A. Abbaspour-Tamijani
A multi-resolution channel select filter topology is proposed for ultra-wideband coverage, as the multi-stage cascade of bimodal filters with self-complementary periodic frequency response. A 4-stage implantation based on PIN diode switches is presented. This prototype covers DC-2.5 GHz in 16 equal bandwidth channels of 156 MHz with a maximum insertion loss of 6.5 dB.
{"title":"A multi-resolution channel-select filter with ultra-wide frequency coverage","authors":"M. Koochakzadeh, A. Abbaspour-Tamijani","doi":"10.1109/MWSYM.2008.4633195","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633195","url":null,"abstract":"A multi-resolution channel select filter topology is proposed for ultra-wideband coverage, as the multi-stage cascade of bimodal filters with self-complementary periodic frequency response. A 4-stage implantation based on PIN diode switches is presented. This prototype covers DC-2.5 GHz in 16 equal bandwidth channels of 156 MHz with a maximum insertion loss of 6.5 dB.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"213 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122853974","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 : 2008-06-15DOI: 10.1109/MWSYM.2008.4633029
A. Marandi, P. So, T. Darcie
A new tool is proposed for simulation of spatial second-order nonlinear interactions of guided waves based on modified one-dimensional finite-difference time-domain (1-D FDTD) calculations with an embedded nonlinear susceptibility tensor. Parallel 1-D engines are used to calculate three-dimensional behaviors according to propagation properties of the waveguides. The method has been used successfully to simulate difference-frequency mixing in GaAs for terahertz generation, and could be applied to a wide range of problems that could not be solved easily by conventional methods.
{"title":"An FDTD-based tool for simulation of nonlinear interactions of guided waves","authors":"A. Marandi, P. So, T. Darcie","doi":"10.1109/MWSYM.2008.4633029","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633029","url":null,"abstract":"A new tool is proposed for simulation of spatial second-order nonlinear interactions of guided waves based on modified one-dimensional finite-difference time-domain (1-D FDTD) calculations with an embedded nonlinear susceptibility tensor. Parallel 1-D engines are used to calculate three-dimensional behaviors according to propagation properties of the waveguides. The method has been used successfully to simulate difference-frequency mixing in GaAs for terahertz generation, and could be applied to a wide range of problems that could not be solved easily by conventional methods.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127050462","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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