Pub Date : 2008-04-23DOI: 10.1109/COMITE.2008.4569899
F. Herraiz-Martínez, L. García-Muñoz, V. González-Posadas, D. Segovia-Vargas
Multi-frequency printed dipoles based on antipodal printed dipoles loaded with metamaterial particles are presented. Split ring resonators (SRRs) are used as metamaterial particles in order to obtain fully printed and planar antennas. First, a simplified model of these antennas is developed. This model is based on a printed dipole loaded with the equivalent circuit of the SRRs. This model shows that the working frequencies are very close to the self-resonant frequencies of the dipole and the SRRs. Moreover, a dual-frequency printed dipole is designed, manufactured and measured. This dipole works simultaneously at 1.32 GHz and 2.82 GHz. Finally, the previous idea is extended to increase the bandwidth of the dual-band dipoles and develop multi-frequency printed dipoles (printed dipoles which work simultaneously at three or more frequencies). This is made by using SRRs with different dimensions.
{"title":"Multi-Frequency Printed Dipoles Loaded with Metamaterial Particles","authors":"F. Herraiz-Martínez, L. García-Muñoz, V. González-Posadas, D. Segovia-Vargas","doi":"10.1109/COMITE.2008.4569899","DOIUrl":"https://doi.org/10.1109/COMITE.2008.4569899","url":null,"abstract":"Multi-frequency printed dipoles based on antipodal printed dipoles loaded with metamaterial particles are presented. Split ring resonators (SRRs) are used as metamaterial particles in order to obtain fully printed and planar antennas. First, a simplified model of these antennas is developed. This model is based on a printed dipole loaded with the equivalent circuit of the SRRs. This model shows that the working frequencies are very close to the self-resonant frequencies of the dipole and the SRRs. Moreover, a dual-frequency printed dipole is designed, manufactured and measured. This dipole works simultaneously at 1.32 GHz and 2.82 GHz. Finally, the previous idea is extended to increase the bandwidth of the dual-band dipoles and develop multi-frequency printed dipoles (printed dipoles which work simultaneously at three or more frequencies). This is made by using SRRs with different dimensions.","PeriodicalId":306289,"journal":{"name":"2008 14th Conference on Microwave Techniques","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125676081","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 : 2008-04-23DOI: 10.1109/COMITE.2008.4569895
L. Dudás, P. Kovacs, R. Seller
Our aim is to develop a microwave antenna whose radiation pattern is electronically controlled. The radiation pattern of an antenna is determined by the Fourier-transform of the complex illumination function on the antenna aperture. This radiation pattern is mechanically fixed so its alteration is impossible. Therefore we construct an antenna system of several antenna elements. All elements are actuated by separate transmitters; we control the amplitude and the phase of the supplying currents of the antenna elements. This way, we are able to control the radiation pattern of the antenna system. The control is computerized so that there is a possibility to change the radiation pattern quickly. The novelty of our antenna system is the realization in X and UMTS band.
{"title":"Digital Beamforming - Linear and Planar Array","authors":"L. Dudás, P. Kovacs, R. Seller","doi":"10.1109/COMITE.2008.4569895","DOIUrl":"https://doi.org/10.1109/COMITE.2008.4569895","url":null,"abstract":"Our aim is to develop a microwave antenna whose radiation pattern is electronically controlled. The radiation pattern of an antenna is determined by the Fourier-transform of the complex illumination function on the antenna aperture. This radiation pattern is mechanically fixed so its alteration is impossible. Therefore we construct an antenna system of several antenna elements. All elements are actuated by separate transmitters; we control the amplitude and the phase of the supplying currents of the antenna elements. This way, we are able to control the radiation pattern of the antenna system. The control is computerized so that there is a possibility to change the radiation pattern quickly. The novelty of our antenna system is the realization in X and UMTS band.","PeriodicalId":306289,"journal":{"name":"2008 14th Conference on Microwave Techniques","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131451423","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 : 2008-04-23DOI: 10.1109/COMITE.2008.4569901
V. Bilik, J. Bezek
Two effects limiting high-power performance of a 2.45-GHz R26-waveguide stub tuner have been investigated by means of electromagnetic simulation: electric breakdown and microwave power dissipation in tuning stub. In the case of electric breakdown, increasing rounding radius of the stub edge from 1 mm to 4 mm was found to decrease maximum electric field strength 2.25- times, leading to fivefold increase of tuner power-handling capacity. Estimation of power dissipated in the tuning stub, based on average surface current density and stub conductivity, shows that stub overheating is not the most critical limiting factor. The described methodology can be applied to any type of waveguide and tuning stub structure.
{"title":"Investigation of High-Power Limits of Stub Tuners by Means of Electromagnetic Simulation","authors":"V. Bilik, J. Bezek","doi":"10.1109/COMITE.2008.4569901","DOIUrl":"https://doi.org/10.1109/COMITE.2008.4569901","url":null,"abstract":"Two effects limiting high-power performance of a 2.45-GHz R26-waveguide stub tuner have been investigated by means of electromagnetic simulation: electric breakdown and microwave power dissipation in tuning stub. In the case of electric breakdown, increasing rounding radius of the stub edge from 1 mm to 4 mm was found to decrease maximum electric field strength 2.25- times, leading to fivefold increase of tuner power-handling capacity. Estimation of power dissipated in the tuning stub, based on average surface current density and stub conductivity, shows that stub overheating is not the most critical limiting factor. The described methodology can be applied to any type of waveguide and tuning stub structure.","PeriodicalId":306289,"journal":{"name":"2008 14th Conference on Microwave Techniques","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131273567","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 : 2008-04-23DOI: 10.1109/COMITE.2008.4569936
K. Wincza, S. Gruszczynski, J. Borgosz
The paper presents an antenna design for use in a nonlinear junction detection device. To achieve wide bandwidth a capacitive feed technique is used in which small probe feed elements are coupled to the radiating patch. In order to minimize the overall antenna size both receiving and transmitting antenna elements have been integrated into one dual-band structure having two separate excitation ports. High isolation between ports is achieved to avoid direct interferences between a transmitter and a receiver. Results of theoretical analysis are presented agree well with the experimental ones.
{"title":"Dual-band Capacitive Feed Antenna for Nonlinear Junction Detection Device","authors":"K. Wincza, S. Gruszczynski, J. Borgosz","doi":"10.1109/COMITE.2008.4569936","DOIUrl":"https://doi.org/10.1109/COMITE.2008.4569936","url":null,"abstract":"The paper presents an antenna design for use in a nonlinear junction detection device. To achieve wide bandwidth a capacitive feed technique is used in which small probe feed elements are coupled to the radiating patch. In order to minimize the overall antenna size both receiving and transmitting antenna elements have been integrated into one dual-band structure having two separate excitation ports. High isolation between ports is achieved to avoid direct interferences between a transmitter and a receiver. Results of theoretical analysis are presented agree well with the experimental ones.","PeriodicalId":306289,"journal":{"name":"2008 14th Conference on Microwave Techniques","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130295301","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 : 2008-04-23DOI: 10.1109/COMITE.2008.4569944
P. Hudec, O. Slezák, J. Zela
In microwave practice, it is often important to measure free-space attenuation of definite radio links or radio systems. These measurements can be accomplished by using a measurement transmitter and a transmitting antenna at one location, and a receiving antenna and a power meter at the second location. Sufficient immunity against reception of parasitic signals that are practically always present in the free-space, especially in relatively densely occupied microwave frequency region, belong among the main problems of such measurements. The designed and realized selective power meter (SPM) solves this problem by using two different filtering methods. Their combination results in a very high selectivity and measurement immunity.
{"title":"Highly Selective Power Meter for Measurement of Free Space Attenuation in Microwave Frequency Region","authors":"P. Hudec, O. Slezák, J. Zela","doi":"10.1109/COMITE.2008.4569944","DOIUrl":"https://doi.org/10.1109/COMITE.2008.4569944","url":null,"abstract":"In microwave practice, it is often important to measure free-space attenuation of definite radio links or radio systems. These measurements can be accomplished by using a measurement transmitter and a transmitting antenna at one location, and a receiving antenna and a power meter at the second location. Sufficient immunity against reception of parasitic signals that are practically always present in the free-space, especially in relatively densely occupied microwave frequency region, belong among the main problems of such measurements. The designed and realized selective power meter (SPM) solves this problem by using two different filtering methods. Their combination results in a very high selectivity and measurement immunity.","PeriodicalId":306289,"journal":{"name":"2008 14th Conference on Microwave Techniques","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133037168","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 : 2008-04-23DOI: 10.1109/COMITE.2008.4569906
V. De Santis, M. Feliziani
A numerical dosimetry procedure is applied to a biological tissue in order to evaluate the temperature increase produced by RF exposure. The originality of the proposed method regards the application of the bio-heat equation in a vascularized region considering a discrete blood vessel structure which operates as a cooling system in the biological region. First, the blood structure is assumed to be a hydraulic system where a laminate incompressible fluid flows. By this approach the blood velocity in all vessels are computed. Then, the diffusion-convection heat equation is analyzed in a three dimensional domain by a differential numerical method based on the finite difference method. A simple test configuration is finally analysed.
{"title":"EMF Exposure: A Numerical Model to Predict the Temperature Increase in Biological Vascularized Tissues","authors":"V. De Santis, M. Feliziani","doi":"10.1109/COMITE.2008.4569906","DOIUrl":"https://doi.org/10.1109/COMITE.2008.4569906","url":null,"abstract":"A numerical dosimetry procedure is applied to a biological tissue in order to evaluate the temperature increase produced by RF exposure. The originality of the proposed method regards the application of the bio-heat equation in a vascularized region considering a discrete blood vessel structure which operates as a cooling system in the biological region. First, the blood structure is assumed to be a hydraulic system where a laminate incompressible fluid flows. By this approach the blood velocity in all vessels are computed. Then, the diffusion-convection heat equation is analyzed in a three dimensional domain by a differential numerical method based on the finite difference method. A simple test configuration is finally analysed.","PeriodicalId":306289,"journal":{"name":"2008 14th Conference on Microwave Techniques","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133429381","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 : 2008-04-01DOI: 10.1109/comite.2008.4569923
H. Bártík
The directional attenuators are devices with attenuation dependent on direction of propagation of RF energy. A new type of the directional attenuator was developed, designed and tested. The advantages of the new directional attenuators are low cost and low attenuation in forward direction, which is from 1 to 2 dB. The attenuation of designed directional attenuators in backward direction is from 7 to 20 dB. The attenuators were developed for frequency band from 2.4 to 2.48 GHz, e.g. for wireless networks according to standards IEEE 802.11b/g.
{"title":"Directional Attenuators","authors":"H. Bártík","doi":"10.1109/comite.2008.4569923","DOIUrl":"https://doi.org/10.1109/comite.2008.4569923","url":null,"abstract":"The directional attenuators are devices with attenuation dependent on direction of propagation of RF energy. A new type of the directional attenuator was developed, designed and tested. The advantages of the new directional attenuators are low cost and low attenuation in forward direction, which is from 1 to 2 dB. The attenuation of designed directional attenuators in backward direction is from 7 to 20 dB. The attenuators were developed for frequency band from 2.4 to 2.48 GHz, e.g. for wireless networks according to standards IEEE 802.11b/g.","PeriodicalId":306289,"journal":{"name":"2008 14th Conference on Microwave Techniques","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129792600","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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