DSpace Arşivi :: by Yazar "Aksen, Ahmet" değerine göre listeleniyor

Yazar "Aksen, Ahmet" seçeneğine göre listele

Listeleniyor 1 - 20 / 41

Cascade synthesis of two-variable lossless two-port networks with lumped elements and transmission lines: a semi-analytic procedure
(Tylor & Francis Ltd, 2001) Aksen, Ahmet; Yarman, Bekir Sıddık Binboğa
Two-variable characterization of cascades composed of lossless two-port networks with lumped elements and transmission lines is considered. The problems associated with the construction of scattering functions in two variables are discussed and for cascade synthesis of two-variable mixed element networks, a semi-analytic procedure utilizing the topologic restrictions is proposed. Some particular mixed lumped-distributed structures for which the proposed procedure ends up with explicit formulas are addressed and the application of the results in real frequency broadband matching is indicated.
Circuit model for given reflectance data constructed with mixed lumped and distributed elements for high speed/high frequency communication systems
(IEEE, 2005) Yarman, Bekir Sıddık Binboğa; Şengül, Metin; Kılınç, Ali; Aksen, Ahmet
In this paper, a reflectance-based "non linear interpolation method" is presented to model the measured or computed data, obtained from a "passive one-port physical device" using mixed lumped and distributed elements. Mixed element model is constructed with cascade connection of series inductors [L], commensurate transmission lines or so called Unit Elements [UE] and shunt capacitors[C]. Basis of the new model rests on the numerical generation of the scattering parameters of the lossless two-port constructed with cascade connection of simple [L]-[UE]-[C] elements which describes a lossless 2-port in Darlington sense. The new modeling technique does not require direct optimization of the circuit elements of the selected topology. Rather, two-variable reflection coefficient is directly determined by means of a non linear but "convergence guaranteed" interpolation process to best fit the given data. A low-pass filter input reflection coefficient modeling example is included to exhibit the utilization of the proposed modeling method.
Computer aided darlington synthesis of an all purpose immittance function
(Istanbul University, 2016) Yarman, Bekir Sıddık Binboğa; Aksen, Ahmet; Köprü, Ramazan; Kumar, Narendra Senthil; Aydın, Çağatay; Atilla, Doğu Çağdaş; Chacko, Prakash
This work is the continuation of our high precision immittance synthesis paper series introduced in IEEE TCAS-I. In the present manuscript, we modified the previously introduced high precision Bandpass LC-ladder synthesis algorithm to include the extraction of finite frequency and right half plane (RHP) transmission zeros of an impedance function as Brune/Darlington Type-C sections. Finite frequency and RHP transmission zeros are extracted employing our newly introduced modified impedance and chain parameters based algorithms one by one. After each transmission zero extraction, remaining immittance function is corrected using parametric approach. It is shown that propsed high precision synthesis algorithms can synthesize immittance functions up to 40 reactive elements with accumulated relative error in the order of 10- 1 . The modified high precision synthesis package is developed in MatLab environment and it is integrated with the real frequency techniques to design matching networks over broadbands. Examples are presented to exhibit the usage of the newly proposed high precision synthesis algorithms.
A computer aided design technique for hybrid and monolithic microwave amplifiers employing distributed equalizers with lumped discontinuities
(IEEE, 2001) Aksen, Ahmet; Yarman, Bekir Sıddık Binboğa
This paper will addres the use of mixed lumped and distributed elements in the matching equalizers of microwave amplifers for hybrid and monolithic MIC realizations. In this work we show how the computer aided real frequency technique can be extended to design broadband amplifiers employing distributed equalizers with lumped discontinuities. The scattering based two-variable description of lossless equalizers with mixed lumped-distributed elements will be discussed and the potential benefits of the approach will be indicated by examples.
Computer aided high precision Darlington synthesis for real frequency matching
(Institute of Electrical and Electronics Engineers Inc, 2014) Yarman, Bekir Sıddık Binboğa; Aksen, Ahmet; Köprü, Ramazan; Aydın, Çağatay; Atilla, Doğu Çağdaş
In this work, we introduce a high precision synthesis algorithm to include the extraction of finite frequency and right half plane (RHP) transmission zeros of an impedance function as Brune/Darlington Type-C sections. After each transmission zero extraction, remaining immittance function is corrected using a parametric approach. It is shown that proposed high precision synthesis algorithm can synthesize immittance functions up to 40 reactive elements with accumulated relative error in the order of 10-1. The high precision synthesis package is integrated with the real frequency techniques to design matching networks over broadbands. Examples are presented to exhibit the usage of the proposed high precision synthesis algorithm.
Construction of some classes of two-variable lossless ladder networks with simple lumped elements and uniform transmission lines
(IEEE, 1998) Sertbaş, Ahmet; Aksen, Ahmet; Yarman, Bekir Sıddık Binboğa
In this paper, explicit two-variable description of some classes of ladder networks of high-pass, bandpass and band-reject types are presented. Up to a certain complexity, for two-element kinds of these type regular structures, explicit expressions describing the twovariable scattering functions are obtained.
Design and implementation of wideband microwave amplifiers based on Normalized Gain Function
(Institute of Electrical and Electronics Engineers Inc., 2014) Köprü, Ramazan; Kılınç, Sedat; Aksen, Ahmet; Yarman, Bekir Sıddık Binboğa
In this work, we introduce the design and implementation of wideband microwave amplifiers based on "Normalized Gain Function (NGF)" method. Normalized Gain Function is defined as the ratio of desired shape or frequency response of the gain function of the amplifier to be designed and shape of the transistor forward gain function. Synthesis of input/output matching networks (IMN/OMN) of the amplifier require target gain curves as the functions of normalized gain function to be tracked in two sequential nonlinear optimization processes. A prototype low power amplifier circuit is produced and measured to show the usability of the design approach.
Design and simulation of miniaturized communication systems employing symmetrical lossless two-ports constructed with two kinds of elements
(IEEE, 2003) Yarman, Bekir Sıddık Binboğa; Aksen, Ahmet; Çimen, Ebru Gürsu
In this paper, a semi-analytic method is presented to describe symmetrical lossless networks with two-kinds of elements, namely, distributed and lumped elements in cascade connection. in terms of the independently chosen parameters, element values of the lossless symmetrical networks are given by explicit formulas up to nine elements. It is expected that the results presented in this paper will find immediate usage in performance assessment, design and simulation of analog/digital wireless communication systems put on MMICs or VLSI chips.
Design of multiband matching ladders without mutual coupling using parametric representation of Brune functions
(John Wiley and Sons Inc, 2020-10-01) Yıldız, Serkan; Aksen, Ahmet; Yarman, Bekir Sıddık Binboğa
In this study, a semianalytical method for the design of mutual coupling free multiband matching networks is introduced. A new parametric representation of Brune functions is used for the construction of multiband ladder network topologies without mutual induction. The method involves the use of Fujisawa's constraints for low pass ladders having finite transmission zeros, in a parametric representation of driving point impedance function resulting in mutual inductance free Brune sections. The developed parametric representation is incorporated with Real Frequency Techniques to design matching networks with a plurality of pass bands. Several illustrative design examples are presented to validate the method.
Design of tunable amplifier using digital capacitors
(IEEE, 2014) Atilla, Doğu Çağdaş; Aydın, Çağatay; Nesimoğlu, Tayfun; Köprü, Ramazan; Aksen, Ahmet; Yarman, Bekir Sıddık Binboğa
In recent days, radio manufacturers are increasingly interested in broadband amplifiers for cellular communication. Demands of customers enforce manufacturers to develop systems compatible for all standards and it is mandatory to accommodate more than one amplifier or tunable amplifier in front end of communication systems. In this paper, design of tunable amplifier is investigated by using Real Frequency Technique and agility of tunable components is provided by digital tunable capacitors.
Dual band filter design for GSM bands using frequency mapping and real frequency technique
(IEEE, 2018) Yıldız, Serkan; Kılınç, Sedat; Aksen, Ahmet; Yarman, Bekir Sıddık Binboğa
In this study, dual band frequency mapping is incorporated with Real Frequency Technique to design a dual band filter for GSM900 and GSM1800/UMTS bands. The proposed real frequency design technique (RFT) involves a parametric representation of input impedance of filter and the use of a dual band (DB) frequency mapping. A direct DB frequency mapping from low pass proto-type network is utilized along with the design and optimization of a low pass prototype network. Microstrip implementation of the designed filter and measurement results of the design are presented.
Dual band filter design using real frequency technique and frequency transformation
(Istanbul Univ, Fac Engineering, Elektrik-Elektronik Muhendisligi Bolumu, 2017) Yıldız, Serkan; Aksen, Ahmet; Yarman, Bekir Sıddık Binboğa
In this work, we present a frequency transformation based dual-band filter design approach using scattering based real frequency technique. In the design process, conventional low-pass to band-pass frequency transformation is integrated with the simplified real frequency technique to construct double pass-band filters. The approach is particularly advantageous for designing matching filters between different termination resistances. As an alternative to a direct low-pass to dual-band frequency transformation, the use of dual-band mapping on a normalized band-pass prototype is investigated for efficient control of the passbands. Application of the proposed approaches for dual-band filters is presented by comparative design examples.
Dual band matching network design via real frequency technique by mapping from a band pass prototype
(IEEE, 2016) Yıldız, Serkan; Aksen, Ahmet; Yarman, Bekir Sıddık Binboğa
In this study, a new method of design for dual band matching network is presented. A transformer-less Band Pass (BP) prototype matching network is synthesized with well-known Simplified Real Frequency Technique (SRFT) via cascaded combination of Low Pass (LP) and High Pass (HP) sections and optimized under LP to BP frequency transformation to create dual band response. Scattering parameters based descriptive functions of transformer-less BP prototype network is obtained. Dual band response is derived via frequency mapping on the produced BP prototype network. The new method combines several advantages both in design and realization step. The application of this method is discussed with sequential transformation based approach. A dual band matching network design for a PIFA antenna is presented. By using this method dual band characteristic is derived with only one step application of frequency mapping which let use to have more practical realizations.
Dual band stop filter design via frequency transformation and synthesis with lumped resonators
(Institution of Engineering and Technology, 2020-05-01) Yıldız, Serkan; Aksen, Ahmet; Kılınç, Sedat; Yarman, Bekir Sıddık Binboğa
This study presents a new compact design technique for dual band stop (DBS) filter. Analytical formulation of DBS frequency transformation/mapping is derived in terms of parametric representation of band characteristic of DBS filter. The analytical derivation of the transformation function is based on sequential application of classical low pass to band stop (LP to BS) and low pass to band pass (LP to BP) transformations. Assigned band characteristic of DBS filter can be achieved by applying the proposed transformation function on an LP prototype network. The explicit network topologies for DBS reactance mapping are presented. Several numerical examples are provided to validate the proposed mapping function. An implantation example of DBS filter for GSM900 and GSM1800/UMTS bands is given. Mixed element realisation of the designed filter and measurement results of the design are presented.
A frequency transformation based real frequency design approach for dual-band matching
(IEEE, 2017) Aksen, Ahmet; Yıldız, Serkan; Yarman, Bekir Sıddık Binboğa
This work describes a real frequency design approach for dual-band matching networks. The proposed design technique employs a direct low-pass to dual pass band frequency transformation in the scattering based real frequency design of transformer free double band matching filters. For prescribed matching pass-bands, the parameters of dual-band frequency transformation are also iterated to enhance the matching band control in the nonlinear optimization process. A dual band matching network design example is presented to illustrate the application of the design approach.
A high precision Cascade Synthesis Technique for real frequency matching involving Brune and Darlington Type-C sections
(IEEE, 2014) Yarman, Bekir Sıddık Binboğa; Aksen, Ahmet; Köprü, Ramazan; Aydın, Çağatay; Atilla, Doğu Çağdaş
In this work, we introduce a high precision cascade synthesis technique for lossless matching networks involving Brune and Darlington Type-C sections. In the present manuscript, we generalized our previously introduced high precision LCladder synthesis algorithm to include the extraction of finite real frequency and right half plane (RHP) transmission zeros of an impedance function as Brune and Darlington Type-C sections respectively. In the modified synthesis algorithm, after each finite frequency and RHP transmission zero extraction, remaining immittance function is corrected using a parametric approach. It is shown that proposed high precision algorithm can synthesize immittance functions of up to 40 reactive elements with accumulated relative error in the order of 10(-1). The modified high precision synthesis package is developed in MatLab environment and it is integrated with the real frequency techniques to design high complexity matching networks over broad bands. An illustrative example is presented to exhibit the usage of the proposed high precision synthesis algorithm.
An immitance based tool for modelling passive one-port devices by means of darlington equivalents
(Urban & Fischer Verlag, 2001) Yarman, Bekir Sıddık Binboğa; Aksen, Ahmet; Kılınç, Ali
An immitance-based method is presented to model measured or computed data, obtained from a "passive one-port physical device" by means of its Darlington equivalent. In other words, the given data is modelled as a lossless two port terminated in a unit resistor. The basis of the new modelling tool rests on the numerical decomposition of the given immitance data into its Foster and minimum parts. Therefore, the proposed technique does not require any choice for the circuit topology to build the model. Rather, the optimum circuit topology that characterises the given data is the natural consequence of the modelling process proposed in this paper. A main algorithm is presented to construct the model from the given data. It is expected that the proposed modelling tool will find practical applications in the behaviour characterisation, simulation, and design of high speed/high frequency analog/digital mobile communication sub-systems manufactured on VLSI chips. An antenna-modelling example is included to systematically exhibit the implementation of the modelling technique.
Immitance data modelling via linear interpolation techniques
(IEEE, 2002) Yarman, Bekir Sıddık Binboğa; Aksen, Ahmet; Kılınç, Ali
With the advancement of the manufacturing technologies to produce new generation analog/digital communication systems, immitance data modelling has gained renewed importance in the literature. Specifically, models are utilised for behaviour characterisation, simulation of physical devices or to design sub-systems with active and passive solid-state components. Therefore, in this paper, new computer aided tools are presented to model one port immitance data by means of linear interpolation techniques. It is remarkable to observe that complex electrical behaviour of physical devices can be simulated with the models built utilising the linear interpolation of a few properly selected measured immitance data. An antenna example is presented to exhibit the implementation of the proposed techniques. It is expected that the new modelling tools will be employed to provide initial circuit topologies to the commercially available analysis/simulation and design packages.
Immitance data modelling via linear interpolation techniques: a classical circuit theory approach
(Wiley-Blackwell, 2004-11) Yarman, Bekir Sıddık Binboğa; Kılınç, Ali; Aksen, Ahmet
With the advancement of the manufacturing technologies to produce new generation analog/digital communication systems, immitance data modelling has gained renewed importance in the literature. Specifically, models are utilized for behaviour characterization, simulation of physical devices or to design sub-systems with active and passive solid-state devices. Therefore, in this paper, new computer aided tools are presented to model one port immitance data by means of linear interpolation techniques. The basic philosophy of the new modelling tools is based on the numerical decomposition of the immitance data into its minimum and Foster parts. Computer algorithms are presented to model the minimum and the Foster parts of the given immitance data. Implementations of these algorithms are exhibited by means of examples. Depending on the application, modelling tools based on linear interpolation techniques may present 'computational and practical' advantages over the existing interpolation techniques, non-linear curve fittings or regression methods. It is expected that the new modelling tools will be utilized to provide initial circuit topologies to the commercially available analysis/simulation and design packages.
Low pass filter design with improved stop-band suppression and synthesis with transformer-free ladders
(John Wiley and Sons Inc, 2021-09) Yıldız, Serkan; Aksen, Ahmet; Kılınç, Sedat; Yarman, Bekir Sıddık Binboğa
A new method to design transformer-free low pass (LP) ladder network with improved stop-band suppression performance is introduced. The parametric representation of back-end impedance of LP filter network is established with minimum impedance part and a Foster reactance part. The constructed impedance function is optimized by using real frequency technique. It has been shown that the proposed method provides LP filters which have superior stop-band suppression in comparison with classical transfer function-based filters with same complexity. The synthesis of the LP filter is obtained with the proposed element extraction procedure and resulted with fully realizable network elements in ladder form. An LP filter design and application by employing the proposed technique is provided. The measurement results of the prototyped filter are presented.

Yazar "Aksen, Ahmet" seçeneğine göre listele

Sayfa Başına Sonuç

Sıralama seçenekleri