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Yayın Multiband and concurrent matching network design(Işık Üniversitesi, 2020-02-05) Yıldız, Serkan; Aksen, Ahmet; Işık Üniversitesi, Fen Bilimleri Enstitüsü, Elektronik Mühendisliği Doktora ProgramıMultiband network design has become a big issue due to the current improvements in RF and MW technologies. Since the new wireless protocols come up fast such as 3G, 4G, 5G etc., the RF and MW hardware must be designed to provide services to all distinct technologies in simultaneous regimes. To avoid interference, noise, harmonics, etc., the use of multiband matching or ?ltering at the front-end or back-end of RF/MW devices is an inevitable work. Particularly multiband matching in a multiband system is always necessary to be sure of proper power transfer between each multiband units. In this thesis, the multiband matching network design problem is addressed under the analytical perspective. Therefore, a deep investigation on network theoretical foundations is performed. In addition, only passive networks are concerned for providing concurrent operation. One of the well-known semi-analytical network design methods, which is called real frequency technique, is taken as a main domain to develop the thesis contributions. Two main approaches are elaborated. The ?rst approach is the generation of proper frequency mapping functions and determination of prototype networks to design multiband matching network. The proposed frequency transformation approach is useful and practical for multiband ?lter and matching network designs. As a second research track of the thesis; a synthesis based approach is aimed to be developed for generalized multiband matching network designs. A proper integration of the proposed approach with RFT matching techniques and examination of the implementation results are provided.Yayın 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 BinboğaA 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.Yayın 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 BinboğaIn 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.Yayın Novel approach to design ultra wideband microwave amplifiers: Normalized gain function method(Spolecnost Pro Radioelektronicke Inzenyrstvi, 2013-09) Köprü, Ramazan; Kuntman, Hulusi Hakan; Yarman, Bekir Sıddık BinboğaIn this work, we propose a novel approach called "Normalized Gain Function (NGF) method" to design low/medium power single stage ultra wide band microwave amplifiers based on linear S parameters of the active device. Normalized Gain Function T-NGF is defined as the ratio of T and vertical bar S-21 vertical bar(2), desired shape or frequency response of the gain function of the-amplifier to be designed and the shape of the transistor forward gain function, respectively. Synthesis of input/output matching networks (IMN/OMN) of the amplifier requires mathematically generated target gain functions to be tracked in two different nonlinear optimization processes. In this manner, NGF not only facilitates a mathematical base to share the amplifier gain function into such two distinct target gain functions, but also allows their precise computation in terms of T-NGF=T/vertical bar S-21 vertical bar(2) at the very beginning of the design. The particular ainplifier presented as the design example operates over 800-5200 MHz to target GSM, UNITS,. Wi-Fi and WiMAX applications. An SRFT (Simplified Real Frequency Technique) based design example supported by simulations in MWO (Micro Wave Office from AWR Corporation) is given using a 1400 mW pHEMT transistor, TGF2021-01 from TriQuint Semiconductor.
