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Yayın A single matching network design for a dual band PIFA antenna via simplified real frequency technique(2006-10) Lindberg, Peter; Şengül, Metin; Çimen, Ebru Gürsu; Yarman, Bekir Sıddık Binboğa; Rydberg, Anders; Aksen, AhmetIn this paper, the matched performance of a dual band PIFA antenna is reported. The return loss of the antenna has been optimized over the popular commercial wireless communication bands of 824-960 MHz and 1710-1990 MHz using only one matching network. The network was synthesized using the Simplified Real Frequency Technique, which yields an "easy to implement circuit topology" and realizable component values. With the implemented matching network, a simultaneous measured bandwidth enhancement of 58% and 127% has been achieved in the low and high frequency band, respectively, without significant reduction of radiation efficiency.Yayın 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, AhmetIn 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.Yayın Unit element bandpass filter design via simplified real frequency technique for UWB microstrip patch antenna(IEEE Computer Society, 2014) Köprü, Ramazan; Kılınç, Sedat; Aksen, Ahmet; Yarman, Bekir Sıddık BinboğaDesign of a UWB (Ultra Wideband) microstrip patch antenna to operate in the first channel of the UWB standard and a bandpass (BP) UE (Unit Element) microstrip filter (BPUEF) for this antenna are studied and presented with promising experimental results. A typical UE BP filter is a lossless 2-port network which is formed with certain number of cascade connected commensurate transmission lines. Based on the simplified real frequency technique (SRFT) in Richards domain, driving point Darlington impedance function of the BPUEF is obtained via optimization such that optimum power transfer would be possible between a PA (power amplifier) and the antenna. Using the UE synthesis, characteristic impedance values of each UE is extracted from the input impedance function. Theoretical design (Matlab), simulation (ADS, Agilent Inc.) and the measurements are shown to be in a high degree of agreement.Yayın Multiband and concurrent matching network design via brune sections(IEEE, 2017) Yıldız, Serkan; Aksen, Ahmet; Yarman, Bekir Sıddık BinboğaA general multiband matching network design methodology for complex load impedance terminations is presented. In the proposed approach, Real Frequency Techniques (RFT) are used to define and optimize the multiband matching network. In the characterization of the multiband network, multiple notch bands are obtained by the employment of finite transmission zeros (FTZ) in the transfer function. Brune section realization of finite transmission zeros and the associated coupled coil free realizations are discussed. A triple band matching network design for a triple band Sierpinski antenna load is presented to illustrate the performance of the proposed approach.Yayın A parametric approach to construct two-variable positive real impedance functions for the real frequency design of mixed lumped-distributed matching networks(IEEE, 2004) Aksen, Ahmet; Pınarbaşı, Hacı; Yarman, Bekir Sıddık BinboğaIn this paper, a parametric approach to construct two-variable positive real driving point impedance functions characterizing lossless ladder networks with mixed lumped and distributed elements is presented. The proposed approach is based on the generation of two-variable positive real impedance functions from the single variable boundary conditions. Utilizing the proposed parametric construction algorithm, real frequency matching technique is extended to the design of matching networks with mixed lumped and distributed elements. The application of the approach is illustrated by a broadband microwave amplifier design incorporating mixed lumped and distributed type matching networks. The resultant design has been compared with the AWR Microwave Office software simulation.Yayın Microwave engineering expertise in Turkey(Institute of Electrical and Electronics Engineers Inc., 2018-05) Yarman, Bekir Sıddık Binboğa; Palamutçuoğulları, Osman; Kaya, İlker; Kızılbey, Oǧuzhan; Aksen, Ahmet; Akın, Tayfun; Özkan, Z. Levent; Oksar, İrfan; Nesimoğlu, TayfunReports on the status of microwave education and technological development in Turkey.Yayın A reflectance-based computer aided modelling tool for high speed/high frequency communication systems(IEEE, 2001) Yarman, Bekir Sıddık Binboğa; Aksen, AhmetA reflectance-based method is presented to model the measured or computed data, obtained from a "passive one-port physical device" by means of its Darlington equivalent. The basis of the new modelling tool rests on the numerical generation of the scattering parameters of the Darlington 2-port from the given reflectance employing the losslessness condition. The proposed technique does not require any choice for the circuit topology to build the model. The circuit topology is the natural consequence of the modelling process.
