Pub Date : 1998-09-07DOI: 10.1109/COMSIG.1998.736966
J. van der Merwe, H. Reader, J. Cloete
A frequency domain method is presented which yields accurate characteristic matrices of uniform multiconductor transmission lines (MTLs). It uses simple two-port network analyzer S-parameter measurements of a set of open-circuit and short-circuited MTL configurations. Transversely inhomogeneous MTLs can be characterized accurately in their quasi-TEM propagation regime. The technique was used to determine the inductance and capacitance matrices of a low loss three conductor ribbon cable above a ground plane. Comparisons with numerically and analytically obtained data are given. Measurements are found to be repeatable for lines of length l
{"title":"S-parameter measurements yielding the characteristic matrices of MTLs","authors":"J. van der Merwe, H. Reader, J. Cloete","doi":"10.1109/COMSIG.1998.736966","DOIUrl":"https://doi.org/10.1109/COMSIG.1998.736966","url":null,"abstract":"A frequency domain method is presented which yields accurate characteristic matrices of uniform multiconductor transmission lines (MTLs). It uses simple two-port network analyzer S-parameter measurements of a set of open-circuit and short-circuited MTL configurations. Transversely inhomogeneous MTLs can be characterized accurately in their quasi-TEM propagation regime. The technique was used to determine the inductance and capacitance matrices of a low loss three conductor ribbon cable above a ground plane. Comparisons with numerically and analytically obtained data are given. Measurements are found to be repeatable for lines of length l</spl lambda//4. The /spl lambda//4 requirement is not found to be a restriction in the MHz regime and only plays a role as line end effects become significant at GHz frequencies. The obtained accuracy is significantly better than previously reported results.","PeriodicalId":294473,"journal":{"name":"Proceedings of the 1998 South African Symposium on Communications and Signal Processing-COMSIG '98 (Cat. No. 98EX214)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123930201","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 : 1998-09-07DOI: 10.1109/COMSIG.1998.736999
W. Perold
The development of a new superconducting logic family, complementary output switching logic (COSL), is described. It is described how the two main problems inhibiting superconducting operation at microwave frequencies, namely magnetic flux trapping and large variations of the nominal component values due to the fabrication process, are solved. A brief overview of the operation of the basic logic gate and the layout process is given. Measured results of the basic gates are given for frequencies up to 18 GHz. The measured results of more complex circuits, such as a code converter and a pseudo-random bit sequence generator, are also presented.
{"title":"Complementary output switching logic: a superconducting voltage-state logic family operating at microwave frequencies","authors":"W. Perold","doi":"10.1109/COMSIG.1998.736999","DOIUrl":"https://doi.org/10.1109/COMSIG.1998.736999","url":null,"abstract":"The development of a new superconducting logic family, complementary output switching logic (COSL), is described. It is described how the two main problems inhibiting superconducting operation at microwave frequencies, namely magnetic flux trapping and large variations of the nominal component values due to the fabrication process, are solved. A brief overview of the operation of the basic logic gate and the layout process is given. Measured results of the basic gates are given for frequencies up to 18 GHz. The measured results of more complex circuits, such as a code converter and a pseudo-random bit sequence generator, are also presented.","PeriodicalId":294473,"journal":{"name":"Proceedings of the 1998 South African Symposium on Communications and Signal Processing-COMSIG '98 (Cat. No. 98EX214)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128984430","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 : 1998-09-07DOI: 10.1109/COMSIG.1998.736971
G. Mayhew-Ridgers, J. Odendaal, J. Joubert
When implementing the gain-transfer method to measure the gain of an antenna, it is tempting to assume that there should be no measurement errors due to non-plane wave effects in the test zone fields, given that both the test antenna and the standard gain antenna have equal aperture dimensions. The reasoning behind this is that both antennas are exposed to the same amplitude and phase variations in the test zone fields, and therefore the measurement errors should cancel out. However, in this paper it is shown through simulated gain measurements, that equal aperture dimensions can indeed result in significant measurement errors if the incident wave is not plane.
{"title":"Accuracy of the gain-transfer method for a standard gain antenna and a test antenna with equal aperture dimensions","authors":"G. Mayhew-Ridgers, J. Odendaal, J. Joubert","doi":"10.1109/COMSIG.1998.736971","DOIUrl":"https://doi.org/10.1109/COMSIG.1998.736971","url":null,"abstract":"When implementing the gain-transfer method to measure the gain of an antenna, it is tempting to assume that there should be no measurement errors due to non-plane wave effects in the test zone fields, given that both the test antenna and the standard gain antenna have equal aperture dimensions. The reasoning behind this is that both antennas are exposed to the same amplitude and phase variations in the test zone fields, and therefore the measurement errors should cancel out. However, in this paper it is shown through simulated gain measurements, that equal aperture dimensions can indeed result in significant measurement errors if the incident wave is not plane.","PeriodicalId":294473,"journal":{"name":"Proceedings of the 1998 South African Symposium on Communications and Signal Processing-COMSIG '98 (Cat. No. 98EX214)","volume":"107 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132598492","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 : 1998-09-07DOI: 10.1109/COMSIG.1998.737006
F. Minnaar, J. Coetzee, J. Joubert
In many signal processing microwave components such as EW receiver hybrids and phase shifters, it may be required to split a microwave signal into twin signals as identical in amplitude and phase as possible. When a device such as a Wilkenson splitter is utilized success depends on the symmetry of the splitter. In special cases, the output ports of the splitter may be required to be on opposite sides of the centre slab of triplate stripline structure, making symmetrical split over a broadband very difficult. A generalized theoretical design for such a splitter is proposed and analysis and measured results presented.
{"title":"The development of an ultra-wideband via connected broadside coupled splitting structure","authors":"F. Minnaar, J. Coetzee, J. Joubert","doi":"10.1109/COMSIG.1998.737006","DOIUrl":"https://doi.org/10.1109/COMSIG.1998.737006","url":null,"abstract":"In many signal processing microwave components such as EW receiver hybrids and phase shifters, it may be required to split a microwave signal into twin signals as identical in amplitude and phase as possible. When a device such as a Wilkenson splitter is utilized success depends on the symmetry of the splitter. In special cases, the output ports of the splitter may be required to be on opposite sides of the centre slab of triplate stripline structure, making symmetrical split over a broadband very difficult. A generalized theoretical design for such a splitter is proposed and analysis and measured results presented.","PeriodicalId":294473,"journal":{"name":"Proceedings of the 1998 South African Symposium on Communications and Signal Processing-COMSIG '98 (Cat. No. 98EX214)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125563832","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 : 1998-09-07DOI: 10.1109/COMSIG.1998.736986
J. Cloete
The power is illustrated of symmetry operations, such as spatial inversion and time reversal, for understanding or simplifying problems which arise in engineering electromagnetics.
对称运算的力量，如空间反演和时间反演，用于理解或简化工程电磁学中出现的问题。
{"title":"On symmetry in engineering electromagnetics","authors":"J. Cloete","doi":"10.1109/COMSIG.1998.736986","DOIUrl":"https://doi.org/10.1109/COMSIG.1998.736986","url":null,"abstract":"The power is illustrated of symmetry operations, such as spatial inversion and time reversal, for understanding or simplifying problems which arise in engineering electromagnetics.","PeriodicalId":294473,"journal":{"name":"Proceedings of the 1998 South African Symposium on Communications and Signal Processing-COMSIG '98 (Cat. No. 98EX214)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127010685","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 : 1900-01-01DOI: 10.1109/COMSIG.1998.736978
A. Isaacson, A. Langman, M. Inggs
Borehole tomography is used to obtain an image of the rock strata between two boreholes. A low-power, compact, wide-bandwidth, coherent system is currently under development at the University of Cape Town. The system uses direct digital synthesis technology (DDS). This paper explores borehole tomography, as well as providing an overview of the system used to extract the requirements.
{"title":"Borehole tomography","authors":"A. Isaacson, A. Langman, M. Inggs","doi":"10.1109/COMSIG.1998.736978","DOIUrl":"https://doi.org/10.1109/COMSIG.1998.736978","url":null,"abstract":"Borehole tomography is used to obtain an image of the rock strata between two boreholes. A low-power, compact, wide-bandwidth, coherent system is currently under development at the University of Cape Town. The system uses direct digital synthesis technology (DDS). This paper explores borehole tomography, as well as providing an overview of the system used to extract the requirements.","PeriodicalId":294473,"journal":{"name":"Proceedings of the 1998 South African Symposium on Communications and Signal Processing-COMSIG '98 (Cat. No. 98EX214)","volume":"165 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130564166","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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