SBMO International Microwave Conference/Brazil,最新文献

{"title":"High Power, Low Recovery Time Balanced Duplexer For VHF Applications","authors":"A. Agarwal, Sushma Gupta, K. Aurbindo, B. K. Sarkar","doi":"10.1109/SBMO.1993.589571","DOIUrl":"https://doi.org/10.1109/SBMO.1993.589571","url":null,"abstract":"","PeriodicalId":219944,"journal":{"name":"SBMO International Microwave Conference/Brazil,","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128066407","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}

{"title":"Three Line Microstrip Couplers On Anisotropic Substrates","authors":"B. Rawat","doi":"10.1109/SBMO.1993.589376","DOIUrl":"https://doi.org/10.1109/SBMO.1993.589376","url":null,"abstract":"","PeriodicalId":219944,"journal":{"name":"SBMO International Microwave Conference/Brazil,","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125601786","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}

{"title":"Effects Of Bulk And MOCVD Thin Film Cover On The Characteristics Of Microstrip Resonators","authors":"K. Joshi, R. Pollard, V. Postoyalko","doi":"10.1109/SBMO.1993.587251","DOIUrl":"https://doi.org/10.1109/SBMO.1993.587251","url":null,"abstract":"Shift in the resonance frequency and an increase in the Q factor of microstrip resonators in the presence of dielectric cover are observed in the frequency range of 2- 26GHz. Various microwave materials are used as a dielectric cover which include bulk alumina, semi-insulating GaAs, RT-Duroid and MOCVD A1203 thin film. Increase in the Q factor is found to vary between 103% to 769% depending upon the cover permittivity and thickness. A process has been proposed to fabricate mu1 tilayer homogeineous microstrip using thin film alumina as a cover material giving rise to increase in the quality factor by 137% to 259 % .","PeriodicalId":219944,"journal":{"name":"SBMO International Microwave Conference/Brazil,","volume":"206 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132642350","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}

{"title":"Intrinsic Mode (IM) Solutions For 3D Wave Propagation In Inhomogeneous Mediums","authors":"L. Sevgi","doi":"10.1109/SBMO.1993.587211","DOIUrl":"https://doi.org/10.1109/SBMO.1993.587211","url":null,"abstract":"Wave propagation tlirougli complex inediums with transverse and longitudinal variations is becoming increasingly important for natural arid man-made applications. Analytical solutions hased 011 the mode concept which are the solutions of the coordinate separable problems can be extended to tlie adiabatic and tlie intrinsic mode concepts to solve more general, non-separable wave probleins including critical transition regions.","PeriodicalId":219944,"journal":{"name":"SBMO International Microwave Conference/Brazil,","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124701080","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}

{"title":"Dynamic Response Of External Cavity Semiconductor Laser - A Multigigabit Per Second Transmission Simulation","authors":"L. de Barros, E. Moschin, R. F. Souza","doi":"10.1109/SBMO.1993.589387","DOIUrl":"https://doi.org/10.1109/SBMO.1993.589387","url":null,"abstract":"The dynamic response of a single mode semiconductor laser coupled to a passive external cavity is analysed through the numerical solution of its rate equations. A complete transmission system is simulated using a model derived from the analogy with transmission lines. Although the optical feedback decreases the damping coefficient of the relaxation oscillations, it causes a considerable reduction on the frequency chirp, always present in intensity modulation. In order to analyse the performance of the external cavity laser under realistic conditions, an optical pulse is propagated through a dispersive fiber and filtered in a receiver. The investigation of pulse broadening and the eye-diagrams indicate that the system capacity can be increased by a factor of 2 by using an external resonator. Introduction A great deal of work has been done towards the enhancement of communication system capacity which has led, among other consequences, to the study and implementation of coherent systems. To implement such systems the performance of conventional semiconductor lasers has to be improved, specially regarding the spectral linewidth. DFB and DBR lasers although having small linewidth still do not achieve the necessary requirements. However, the coupling of a semiconductor laser to an external cavity can represent a 1000-fold spectral linewidth reduction [l], Another major problem always present on high bit rates intensity modulation lightwave systems is the frequency chirp. In this case the modulation of the carrier density induces a variation on the refractive index which causes a change in the emission frequency. Here, since the external cavity resonant frequency is independent on carrier flutuations the coupled configuration ECSL (external cavity semiconductor laser) reduces chirp considerably. Therefore external cavity lasers are of interest for coherent and intensity modulation optical systems. In this paper, a complete time-domain analysis of the ECSL performance is presented. The study is based on the numerical solution of the ECSL rate equations. On deriving these equations, a new approach is used, based on an equivalency with transmission lines. It consists of the analysis of the propagating field components inside the diode leading to the system rate equations [4] that are numerically solved. A similar approach was used in [2], where different assumptions led to an analytical solution. Also, the assumptions made in order to derive and solve the system of rate equations and the numerical solution itself are discussed. The last section is divided in two parts. First, the response of the ECSL","PeriodicalId":219944,"journal":{"name":"SBMO International Microwave Conference/Brazil,","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115416039","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}

{"title":"A Study Into A Low Cost Element For A Mobilesat Antenna Array","authors":"S. T. Jellett, M. Bialkowski","doi":"10.1109/SBMO.1993.587204","DOIUrl":"https://doi.org/10.1109/SBMO.1993.587204","url":null,"abstract":"A study into minimising the cost of an antenna array element suitable for use in mobile satellite communications is presented. Stacked configurations for a circular microstrip antenna fed from coaxial lines are considered. A comparison is made between two variations of array ellements with and without lower layer dielectrics. Experimental results including return loss and input impedance plots for bolth types of antenna, are presented in this paper.","PeriodicalId":219944,"journal":{"name":"SBMO International Microwave Conference/Brazil,","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130023724","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}

{"title":"The Optimization Synthesis Of Matching Network And Idler Circuit For Varactor Frequency Multipliers","authors":"Jiadong Huang, Z. Ding","doi":"10.1109/SBMO.1993.587223","DOIUrl":"https://doi.org/10.1109/SBMO.1993.587223","url":null,"abstract":"T h i s pape r d e s c r i b e s a new method t o s y n t h e s i z e a v a r a c t o r f r equency m u l t i p l i e r , w h i c h i s based on q u a s i l i n e a r a n a l y s i s of t h e m u l t i p l i e r as a whole w i t h t h e h e l p of computer o p t i m i z a t i o n , i n s t e a d of d e s i g n i n g t h e i n p u t and o u t p u t matching networks as w e l l a:; i d l e r c i r c u i t s e p a r a t e l y . The o p t i m i z a t i o n and experiment examples i n this; pape r have shown t h a t t h e approach i s v e r y e f f e c t i v e and s u c c e s s f u l . I n t r o d u c t i o n A s w e know, t h e d e s i g n of v a r a c t o r f r equency m u l t i p l i e r s i n e s s e n c e i s a network s y n t h e s i s problem,,once t h e v a r a c t o r dynamic impedance a t i n p u t , o u t p u t and i d l e r f r e q u e n c i e s have been c a l c u l a t e d i n t h e l i s t f o r m [ l ] . I n o r d e r t o e n s u r e h igh conve r s ion e f f i c i e n c y , t h e i n p u t and o u t p u t networks are conjug a t e l y matched t o t h e v a r a c t o r dynamic impedance a t i n p u t and o u t p u t f requenc i e s r e s p e c t i v e l y . Moreover,, t h e i d l e r c i r c u i t i s r e s o n a t e d a t i d l e r f requency t o a l l o w i d l e r energy t o ex t r eme ly d r i v e v a r a c t o r . Of c o u r s e , t h e above mentioned c a l c u l a t i o n s of v a r a c t o r dynamic impedance are based on t h e f o l l o w i n g assumpt i o n s , .The i n p u t and o u t p u t p o s s e s s i d e a l i s o l a t i o n . .The v a r a c t o r c u r r e n t i s c o n s t r a i n e d t o f low o n l y a t t h e i n p u t , o u t p u t and d e s i r e d i d l e frequency., A s a m a t t e r of f a c t , t h e m u l t i p l i e r f i l t e r s do n o t p o s s i b l y p r o v i d e i d e a l open o r s h o r t performances a t co r re spond ing f r e q u e n c i e s and have n o n n e g l i g i b l e rea c t a n c e . On t h e o t h e r hand, because of t h e v a r a c t o r p a r a s i t i c p a r a m e t e r s , t h e i d l e r c i r c u i t , such as a q u a r t e r wavelength open s t u b , i s n o t r e a l l y resonan t a t i d l e r frequency.As a r e s u l t , o t h e r harmonic c u r r e n t s b e s i d e s i n p u t l o u t p u t and i d l e f r equency may occur i n t h e v a r a c t o r . The i n p u t and o u t p u t c i r c u i t s w i l l i n t e r f e r e w i t h each o t h e r . For e x a m p l e , a d j u s t i n g t h e o u t p u t c i r c u i t may change i n p u t impedance of f-requency m u l t i p l i e r o r v a r a c t o r o p e r a t i n g s t a t e . Cons ide r ing t h e s e s i t u a t i o n , t h e m u l t i p l i e r d e s i g n becomes much more complicated. D e s c r i p t i o n of o p t i m i z a t i o n t e c h n i q u e The m u l t i p l i e r a n a l y s i s i s based upon ABCD pa rame te r s of t h e c i r c u i t elements. T h i s i s a s t a n d a r d network a n a l y s i s t e","PeriodicalId":219944,"journal":{"name":"SBMO International Microwave Conference/Brazil,","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128928551","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}

{"title":"Light-Controlled MMW Beam Scanner","authors":"G. Webb, L. H. Pinck","doi":"10.1109/SBMO.1993.587246","DOIUrl":"https://doi.org/10.1109/SBMO.1993.587246","url":null,"abstract":"We describe a novel beam scanning method for microwave or MMW radiation. The method employs a semiconductor or photoconductor wafer in which a spatially varying density of charge carriers is created by optical injection. The induced electron/hole plasma of free carriers alters the dielectric constant of the wafer locally and thereby attenuates incident MMW radiation. A spatially varying density of free carriers can be made to diffract the incident MMW radiation into a beam. Because the wafer responds rapidly to changes in conditions which produce carriers, it is possible to rapidly change the diffractive conditions and thus scan the beam.","PeriodicalId":219944,"journal":{"name":"SBMO International Microwave Conference/Brazil,","volume":"369 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123406406","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}

{"title":"Weighted Residual Finite Element Method For General Nonhermitian Anisotropic Media","authors":"C. Krowne","doi":"10.1109/SBMO.1993.587219","DOIUrl":"https://doi.org/10.1109/SBMO.1993.587219","url":null,"abstract":"The weighted residual meithod is developed here for 3 D electromagnetic problems where the medium is nonhermitian, anisotropic, and lossy. Examples of unsymmetric media include, but are not limited to, gyroelectric, gyromagnetic, g y r o e l e c t r o m a g n e t i c , g y r o e l e c t r o c h i r a l , g y r o m a g n e t o c h i r a l , g y r o e l e c t r o magnetochiral , and media displaying gyroelectromagnet ic-opt ical activity b e h a v i o r .","PeriodicalId":219944,"journal":{"name":"SBMO International Microwave Conference/Brazil,","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116982034","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}

{"title":"A Complete Set Of Passband Tapped Circuits And Practical Application Range","authors":"A. Podcameni, M.S. Cordeiro de Mello","doi":"10.1109/SBMO.1993.589360","DOIUrl":"https://doi.org/10.1109/SBMO.1993.589360","url":null,"abstract":"Tapped resonant LC circuits are investigated here in order to determine, in both qualitative and quantitative ways, how they deviate from previously proposed models. Mismatch, frequency shift and bandwidth shrinkage are observed. Limits for practical use suggested. Moreover, two additional tapped individuals are offered and modeled for the benefit of complex load matching applications. Introduction: The tapped capacitor and tapped inductor circuits, shown in Fig. l(a) and (c), respectively, have the same kind of transfer function. They are sometimes called as capacitor or inductor transformers [l], or parallel transformerlike network [2]. Their advantage is to provide the selectivity of a passband LC circuit combined with the effect of a physical transformer. Clarke and Hess [2] have mentioned the two above circuits and it was shown that, if some conditions are met, the equivalent circuits may be those of Fig. l(b) and (d), respectively. The correspondence between the circuit elements and the models is provided in Table 1. The equivalent circuits possess a shunt LC and an ideal transformer. The presence of the transfoFmer opens up the possibility of matching a step impedance: n = R / R This is a substantial improvement over the single passband LC circuit, where, for maximum power transfer condition one must always have: RG=RL. G L' Furthermore, in Fig. l(b) and (d), it is immaterial which side of the circuit the generator is placed at; these circuits may then perform a step-up or a step-down impedance transformation. While not mentioned previously, both Fig. l(a) and (c) circuits are in a Pi-configuration. It follows that for each of these circuits a correspondent Tee-configuration may now be introduced, This is shown in Fig l(e) and (9). The new proposed models are those in Fig. l(f) and (h), respectively: a series LC and an ideal transformer. Again, equivalence between circuits and models may be seen in Table 1. All four options are capable of matching an impedance step and presenting a bandpass shape equivalent to that of an LC. This four topologies set may be extremely useful when matching a complex load [3]. By selecting the right circuit, one is able to look into either port and see any of the four basic elements: shunt C, series C, shunt L or series L. The best configuration for absorbing an specific existent parasitic reactance may then be elected. The matching of microwave transistors, antennas, optical devices -lasers or photodetectorsis a suggested utilization.","PeriodicalId":219944,"journal":{"name":"SBMO International Microwave Conference/Brazil,","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132571108","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}