Pub Date : 1978-10-01DOI: 10.1109/EUMA.1978.332559
P. J. Richards, A. Anderson
The principle of identifying concealed object shapes by microwave holography has become established in recent years. An important application would be the imaging of buried cables and pipes if the problem of the high attenuation of ground and the strong surface return could be overcome. It is shown in the present work that a synthetic aperture imaging technique based on polarization discrimination mitigates these problems. The technique has been tested in the real urban environment by producing an image of a gas pipe at depths up to 0.25m below the ground surface. An area of ground is scanned with 0.95GHz radiation, the backscatter is recorded in complex form, and the data is computer-processed to produce focussed images on a 16-level TV display.
{"title":"Microwave Images of Sub-Surface Utilities in an Urban Environment","authors":"P. J. Richards, A. Anderson","doi":"10.1109/EUMA.1978.332559","DOIUrl":"https://doi.org/10.1109/EUMA.1978.332559","url":null,"abstract":"The principle of identifying concealed object shapes by microwave holography has become established in recent years. An important application would be the imaging of buried cables and pipes if the problem of the high attenuation of ground and the strong surface return could be overcome. It is shown in the present work that a synthetic aperture imaging technique based on polarization discrimination mitigates these problems. The technique has been tested in the real urban environment by producing an image of a gas pipe at depths up to 0.25m below the ground surface. An area of ground is scanned with 0.95GHz radiation, the backscatter is recorded in complex form, and the data is computer-processed to produce focussed images on a 16-level TV display.","PeriodicalId":429268,"journal":{"name":"1978 8th European Microwave Conference","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126796052","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 : 1978-10-01DOI: 10.1109/EUMA.1978.332508
D. Dorsi
Conventional frequency multipliers using step-recovery-diodes operate on narrow or moderate instantaneous bands. However, multipliers operating on bandwiths of 10 to 15% of the nominal frequency are needed in local oscillator generators for frequency agile up and down converter applications. This paper describes a microstrip frequency doubler, using thin film microwave circuit technology, in which a pair of SRDs, pumped in phase opposition, generates power in the common output line at even harmonics only, mainly the second. Such a technique allows wide-band doublers to be designed, since they do not need a tuned output network, which is the most important bandwidth limiting factor in conventional circuits.
{"title":"Wide Band Frequency Doubler","authors":"D. Dorsi","doi":"10.1109/EUMA.1978.332508","DOIUrl":"https://doi.org/10.1109/EUMA.1978.332508","url":null,"abstract":"Conventional frequency multipliers using step-recovery-diodes operate on narrow or moderate instantaneous bands. However, multipliers operating on bandwiths of 10 to 15% of the nominal frequency are needed in local oscillator generators for frequency agile up and down converter applications. This paper describes a microstrip frequency doubler, using thin film microwave circuit technology, in which a pair of SRDs, pumped in phase opposition, generates power in the common output line at even harmonics only, mainly the second. Such a technique allows wide-band doublers to be designed, since they do not need a tuned output network, which is the most important bandwidth limiting factor in conventional circuits.","PeriodicalId":429268,"journal":{"name":"1978 8th European Microwave Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129195514","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 : 1978-10-01DOI: 10.1109/EUMA.1978.332623
G. Mourier
The active role of the electrons in a gyrotron can be expressed, in the linear approximation, by a tensorial polarizability. Having calculated that quantity for a given electron beam it is possible to predict a number of effectsdue to the self-field of the beam.
{"title":"Role of the Space Charge and the Velocity Distribution in Gyrotrons and Related Devices","authors":"G. Mourier","doi":"10.1109/EUMA.1978.332623","DOIUrl":"https://doi.org/10.1109/EUMA.1978.332623","url":null,"abstract":"The active role of the electrons in a gyrotron can be expressed, in the linear approximation, by a tensorial polarizability. Having calculated that quantity for a given electron beam it is possible to predict a number of effectsdue to the self-field of the beam.","PeriodicalId":429268,"journal":{"name":"1978 8th European Microwave Conference","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121999946","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 : 1978-10-01DOI: 10.1109/EUMA.1978.332561
O. Calla, N. Pillai, O. P. Kaushik, V. H. Bora
{"title":"Crop and Vegetation Studies Using X-Band Scatterometer","authors":"O. Calla, N. Pillai, O. P. Kaushik, V. H. Bora","doi":"10.1109/EUMA.1978.332561","DOIUrl":"https://doi.org/10.1109/EUMA.1978.332561","url":null,"abstract":"","PeriodicalId":429268,"journal":{"name":"1978 8th European Microwave Conference","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126202137","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 : 1978-10-01DOI: 10.1109/EUMA.1978.332534
P. Combes
For a circular radiating aperture, the G.T.D. diverges on the axial caustic. We show that the caustic correcting factor proposed by Keller can only be used in farfield zone for, in near field zone, it gives different (and inacurrate) results in the E or H plane. We demonstrate that the exact value of the diffracted field on the axis is the average of Keller's results in the E and H planes, and we generalize this calculus in the case of two any orthogonal planes. On the axis and in its neighborhood, the results obtained by this new method well agrees with that given by Kottler's formulas and progressively fit together with that of G.T.D.
{"title":"A New Method for Suppressing the Axial Divergence of G.T.D. in the Study of the Circular aperture in its Rayleigh's Zone","authors":"P. Combes","doi":"10.1109/EUMA.1978.332534","DOIUrl":"https://doi.org/10.1109/EUMA.1978.332534","url":null,"abstract":"For a circular radiating aperture, the G.T.D. diverges on the axial caustic. We show that the caustic correcting factor proposed by Keller can only be used in farfield zone for, in near field zone, it gives different (and inacurrate) results in the E or H plane. We demonstrate that the exact value of the diffracted field on the axis is the average of Keller's results in the E and H planes, and we generalize this calculus in the case of two any orthogonal planes. On the axis and in its neighborhood, the results obtained by this new method well agrees with that given by Kottler's formulas and progressively fit together with that of G.T.D.","PeriodicalId":429268,"journal":{"name":"1978 8th European Microwave Conference","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132767054","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 : 1978-10-01DOI: 10.1109/EUMA.1978.332613
I. Frigyes
In the Voice Under Data system relatively high capacity digital signals are transmitted together with relatively low capacity analog le. g. FDMI signals. In present digital microwave links the system can be used e.g. for service channel transmission while in future nearly-all-digital networks its significance will probably grow. In the VUD system QPSK is used for the digital modulation and FM for the anlog one. QPSK demodulation is implemented coherently, while FM demodulation via the carrier synchrony zing loop is applied. The main properties of the VUD system such as digital - to - analog intermodulation noise, error rate due to the frequency modulation, effect of the total noise are investigated. Both NRZ and biphase signalling are considered. It is shown that in some cases the latter is superior even from the spectrum-utilization point of view.
{"title":"Voice under Data: A Method for Transmitting Hybrid Information over Microwave Communication Links","authors":"I. Frigyes","doi":"10.1109/EUMA.1978.332613","DOIUrl":"https://doi.org/10.1109/EUMA.1978.332613","url":null,"abstract":"In the Voice Under Data system relatively high capacity digital signals are transmitted together with relatively low capacity analog le. g. FDMI signals. In present digital microwave links the system can be used e.g. for service channel transmission while in future nearly-all-digital networks its significance will probably grow. In the VUD system QPSK is used for the digital modulation and FM for the anlog one. QPSK demodulation is implemented coherently, while FM demodulation via the carrier synchrony zing loop is applied. The main properties of the VUD system such as digital - to - analog intermodulation noise, error rate due to the frequency modulation, effect of the total noise are investigated. Both NRZ and biphase signalling are considered. It is shown that in some cases the latter is superior even from the spectrum-utilization point of view.","PeriodicalId":429268,"journal":{"name":"1978 8th European Microwave Conference","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132988824","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 : 1978-10-01DOI: 10.1109/EUMA.1978.332591
W. Buck
High-Frequency-Tumor-Therapy requires heating of a well defined region, whereas the surrounding parts should remain unaffected. This problem can be solved by dielectric HF-heating combined with simultaneous cooling of the probe inside the human body. The requirements and the construction of the probe will be reported on. Some theoretical and practical results will also be given.
{"title":"Slotted Cylinder Antenna for Selective Electromagnetic Heating Inside the Human Body","authors":"W. Buck","doi":"10.1109/EUMA.1978.332591","DOIUrl":"https://doi.org/10.1109/EUMA.1978.332591","url":null,"abstract":"High-Frequency-Tumor-Therapy requires heating of a well defined region, whereas the surrounding parts should remain unaffected. This problem can be solved by dielectric HF-heating combined with simultaneous cooling of the probe inside the human body. The requirements and the construction of the probe will be reported on. Some theoretical and practical results will also be given.","PeriodicalId":429268,"journal":{"name":"1978 8th European Microwave Conference","volume":"117 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131920796","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 : 1978-10-01DOI: 10.1109/EUMA.1978.332624
M.C. Green, R. A. Tuck
The reason for the reduced effective work function of osmium coated dispenser cathodes has been investigated using emission microscopy, scanning electron microscopy, electron microprobe analysis and X-ray photo electron spectroscopy. The results indicate that the presence of osmium increases the thickness of the emitting layer and that this layer contains osmium which is chemically combined with the barium to form oxy-anion compounds. On partially coated cathodes an area of enhanced emission was observed at the tungsten/osmium interface.
{"title":"Recent Studies of the Chemical and Physical Processes in Thermionic Cathodes","authors":"M.C. Green, R. A. Tuck","doi":"10.1109/EUMA.1978.332624","DOIUrl":"https://doi.org/10.1109/EUMA.1978.332624","url":null,"abstract":"The reason for the reduced effective work function of osmium coated dispenser cathodes has been investigated using emission microscopy, scanning electron microscopy, electron microprobe analysis and X-ray photo electron spectroscopy. The results indicate that the presence of osmium increases the thickness of the emitting layer and that this layer contains osmium which is chemically combined with the barium to form oxy-anion compounds. On partially coated cathodes an area of enhanced emission was observed at the tungsten/osmium interface.","PeriodicalId":429268,"journal":{"name":"1978 8th European Microwave Conference","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130522646","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 : 1978-10-01DOI: 10.1109/EUMA.1978.332570
H. Sundara, P. Guillon, Y. Garault
This paper discusses a new type of dielectric resonator filter wherein the cylindrical dielectric resonators have been enclosed in evanescent cylindrical metallic cavities. The electromagnetic fields inside the metallic cavity have been derived assuming the dipolar TE01p dielectric resonator as a density of magnetic moment centered inside the metallic cavity. Coupling between two such cavities has been determined and a two cavity filter has been realised which shows good agreement with the theoretical results.
{"title":"A New Type of Dielectric Resonator Filter","authors":"H. Sundara, P. Guillon, Y. Garault","doi":"10.1109/EUMA.1978.332570","DOIUrl":"https://doi.org/10.1109/EUMA.1978.332570","url":null,"abstract":"This paper discusses a new type of dielectric resonator filter wherein the cylindrical dielectric resonators have been enclosed in evanescent cylindrical metallic cavities. The electromagnetic fields inside the metallic cavity have been derived assuming the dipolar TE01p dielectric resonator as a density of magnetic moment centered inside the metallic cavity. Coupling between two such cavities has been determined and a two cavity filter has been realised which shows good agreement with the theoretical results.","PeriodicalId":429268,"journal":{"name":"1978 8th European Microwave Conference","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131798098","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 : 1978-10-01DOI: 10.1109/EUMA.1978.332592
S. Stuchly, M. Stuchly
Great interest in applications of microwave power in cancer therapy through hyperthermia has recently been observed. The basic requirements for microwave power applicators in medical applications are outlined and the presently available designs are reviewed. The design principles and preliminary experimental results for a new type of applicators -- the multimode square - aperture direct contact applicators are presented. The new designs offer improved cross-sectional uniformity of heating. Specially shaped choke-equipped flanges limit the leakage.
{"title":"Multimode Square Waveguide Applicators for Medical Applications of Microwave Power","authors":"S. Stuchly, M. Stuchly","doi":"10.1109/EUMA.1978.332592","DOIUrl":"https://doi.org/10.1109/EUMA.1978.332592","url":null,"abstract":"Great interest in applications of microwave power in cancer therapy through hyperthermia has recently been observed. The basic requirements for microwave power applicators in medical applications are outlined and the presently available designs are reviewed. The design principles and preliminary experimental results for a new type of applicators -- the multimode square - aperture direct contact applicators are presented. The new designs offer improved cross-sectional uniformity of heating. Specially shaped choke-equipped flanges limit the leakage.","PeriodicalId":429268,"journal":{"name":"1978 8th European Microwave Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1978-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130001626","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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