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.2008.4633068
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.2008.4633175
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.2008.4633142
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.2008.4633070
O. Hammi, S. Carichner, B. Vassilakis, F. Ghannouchi
In this paper, an experimental approach is proposed to accurately identify, under a modulated signal drive, the memoryless nonlinearity of power amplifiers exhibiting memory effects. It is experimentally demonstrated that, when they are present, memory effects bias the extracted static nonlinearity. Accordingly, the sampling rate of the WCDMA test signal waveform is varied to reduce the signal’s bandwidth. It is shown that this approach minimizes the memory effects contribution to the amplifier’s nonlinear behavior and leads to accurate characterization of the ‘true’ static nonlinearity. The performance of the proposed approach is then assessed through experimental memoryless digital predistortion.
{"title":"Novel approach for static nonlinear behavior identification in RF power amplifiers exhibiting memory effects","authors":"O. Hammi, S. Carichner, B. Vassilakis, F. Ghannouchi","doi":"10.1109/MWSYM.2008.4633070","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633070","url":null,"abstract":"In this paper, an experimental approach is proposed to accurately identify, under a modulated signal drive, the memoryless nonlinearity of power amplifiers exhibiting memory effects. It is experimentally demonstrated that, when they are present, memory effects bias the extracted static nonlinearity. Accordingly, the sampling rate of the WCDMA test signal waveform is varied to reduce the signal’s bandwidth. It is shown that this approach minimizes the memory effects contribution to the amplifier’s nonlinear behavior and leads to accurate characterization of the ‘true’ static nonlinearity. The performance of the proposed approach is then assessed through experimental memoryless digital predistortion.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"81 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":"124879984","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.2008.4633055
K. Lyon, E. Kan
Nonlinear transmission lines (NLTL) have received considerable attention for their frequency conversion, fast pulse generation, and rise/falltime compression properties. Here we present a new mode of operation for the NLTL which uses falltime compression to generate short RF pulses near the Bragg cutoff frequency. While this phenomenon has been reported in circuit model simulations, we demonstrate, to our knowledge, its first experimental verification. We demonstrate control of the pulse center frequency using next-nearest neighbor coupling and examine the feasibility of MMIC implementation. Our resulting devices generate short microwave pulses suitable for short range wireless communication. The frequency conversion is non-harmonic and requires no active bias currents.
{"title":"Microwave pulse generation using the Bragg cutoff of a nonlinear transmission line","authors":"K. Lyon, E. Kan","doi":"10.1109/MWSYM.2008.4633055","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633055","url":null,"abstract":"Nonlinear transmission lines (NLTL) have received considerable attention for their frequency conversion, fast pulse generation, and rise/falltime compression properties. Here we present a new mode of operation for the NLTL which uses falltime compression to generate short RF pulses near the Bragg cutoff frequency. While this phenomenon has been reported in circuit model simulations, we demonstrate, to our knowledge, its first experimental verification. We demonstrate control of the pulse center frequency using next-nearest neighbor coupling and examine the feasibility of MMIC implementation. Our resulting devices generate short microwave pulses suitable for short range wireless communication. The frequency conversion is non-harmonic and requires no active bias currents.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"24 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":"131324616","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.2008.4633019
R. Santhakumar, Yi Pei, U. Mishra, R. York
Two monolithic broadband distributed amplifiers have been designed and fabricated using AlGaN/GaN HEMTs. One of them uses a standard HEMT for the unit cell and shows a measured S21 of 5.2±1dB from 1-50GHz. The second distributed amplifier uses dual-gate HEMTs for the unit cell and achieves a measured S21 of 12±1dB from 2-32GHz. The process consists of 200nm gate-length HEMTs, CPW transmission lines, MIM capacitors and thin-film resistors. The dual-gate distributed amplifier achieves a CW peak output power of 1W and a PAE of about 16% at 4GHz.
{"title":"Monolithic millimeter-wave distributed amplifiers using AlGaN/GaN HEMTs","authors":"R. Santhakumar, Yi Pei, U. Mishra, R. York","doi":"10.1109/MWSYM.2008.4633019","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4633019","url":null,"abstract":"Two monolithic broadband distributed amplifiers have been designed and fabricated using AlGaN/GaN HEMTs. One of them uses a standard HEMT for the unit cell and shows a measured S21 of 5.2±1dB from 1-50GHz. The second distributed amplifier uses dual-gate HEMTs for the unit cell and achieves a measured S21 of 12±1dB from 2-32GHz. The process consists of 200nm gate-length HEMTs, CPW transmission lines, MIM capacitors and thin-film resistors. The dual-gate distributed amplifier achieves a CW peak output power of 1W and a PAE of about 16% at 4GHz.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"3 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":"130166701","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.2008.4632939
S. Liberatoscioli, M. Mattes, M. Guglielmi, D. Schmitt, C. Ernst
In this paper an innovative manufacturing technology is presented that combines electroforming and CFRP (Carbon Fiber Reinforced Plastic) application and thus could be an enabling technology to achieve tuningless lightweight RF passive hardware with complex geometries. In order to demonstrate the performances achievable with this manufacturing process, a highly sensitive 0.14% fractional bandwidth dual mode filter centered at 19.8GHz was fabricated and tested. The flange interface of the filter was an integral part of the hardware and the total weight four times lighter than an equivalent part made from INVAR.
{"title":"Innovative manufacturing technology for RF Passive devices combining electroforming and CFRP application","authors":"S. Liberatoscioli, M. Mattes, M. Guglielmi, D. Schmitt, C. Ernst","doi":"10.1109/MWSYM.2008.4632939","DOIUrl":"https://doi.org/10.1109/MWSYM.2008.4632939","url":null,"abstract":"In this paper an innovative manufacturing technology is presented that combines electroforming and CFRP (Carbon Fiber Reinforced Plastic) application and thus could be an enabling technology to achieve tuningless lightweight RF passive hardware with complex geometries. In order to demonstrate the performances achievable with this manufacturing process, a highly sensitive 0.14% fractional bandwidth dual mode filter centered at 19.8GHz was fabricated and tested. The flange interface of the filter was an integral part of the hardware and the total weight four times lighter than an equivalent part made from INVAR.","PeriodicalId":273767,"journal":{"name":"2008 IEEE MTT-S International Microwave Symposium Digest","volume":"10 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120985037","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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