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2013 - 201924
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Yazar: Köprü, Ramazan × İndeks: Conference Proceedings Citation Index – Science (CPCI-S) ×

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Listeleniyor 1 - 10 / 24
  • Küçük Resim
    Yayın
    2W wideband microwave PA design for 824-2170 MHz band using normalized gain function method
    (IEEE, 2013) Köprü, Ramazan; Kuntman, Hulusi Hakan; Yarman, Bekir Sıddık Binboğa
    In this work, we present the design of a 2W linear wideband microwave PA (power amplifier) targeted to operate in 824-2170 MHz mobile frequency range covering GSM850, EGSM, DCS, PCS and WCDMA. The design is basically based on the NGF (Normalized Gain Function) method which is very recently introduced into the literature. NGF is defined as the ratio of T and |S-21|(2), i.e. T-NGF= T/|S-21|(2), shape 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 target gain functions, which are mathematically generated in terms of TNGF. The particular transistor used in the design is FP31QF, a 2W HFET from TriQuint Semiconductor. Theoretical PA performance obtained in Matlab is shown to be in a very high agreement with the simulated performance in MWO (Microwave Office) of AWR Inc.
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    A low loss, low voltage and high Q active inductor with multi-regulated cascade stage for RF applications
    (Institute of Electrical and Electronics Engineers Inc., 2015) Momen, Hadi Ghasemzadeh; Yazgı, Metin; Köprü, Ramazan
    Numerous structural planning of active inductors have been proposed as of not long ago in literature which showing tuning conceivable outcomes, low chip area and offering integration facility, they constitute promising architecture to replace passive inductors in RF circuits. The modified of a conventional active inductor based on Gyrator-C topology consisting of both transconductance stages realized by common-source configuration with multi-regulated cascade stage is presented. The Q factor and value of active inductor is adjusted with bias current and flexible capacitance, respectively. Multi regulated cascade stage is used to boost gain of input impedance and inductor value and decrease series resistance of designed inductor witch caused loss. The circuit is suitable for low voltage operation, high quality factor and low power dissipation. Simulation results are provided for 90 nm TSMC CMOS process with 1 V supply voltage. Self-resonance frequency and power consumption of active inductor is 8.9 GHz and 1.2 mW, respectively.
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    CMOS high-performance UWB active inductor circuit
    (Institute of Electrical and Electronics Engineers Inc, 2016) Momen, Hadi Ghasemzadeh; Yazgı, Metin; Köprü, Ramazan; Saatlo, Ali Naderi
    In order to maximize efficiency of the designed gyrator-based active inductor, advanced circuit techniques are used. Loss and noise are most important features of the AIs, where they should be low enough to have high-performance device. The gyrator-C topology is used to design a new low-loss and low-noise active inductor. The gyrator-C topology is potentially high-Q and all transistors are utilized in common-source configuration to have high impedance in input-output nodes. All transistors are free of body effect. The p-type differential pair input transistors and the feed forward path are employed to decrease noise of the proposed circuit. Additionally, inductance value and quality factor are adjusted by variation bias current which gives to the device tunable capability. HSPICE simulation results are presented to verify the performance of the circuit, where the 180 nm CMOS process and 1.8 V power supply are used. The noise voltage and power dissipation are less than 2.8 nV/ ? Hz and 1.3 mW, respectively.
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    Yayın
    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.
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    Yayın
    A tunable inductance topology to realize frequency tunable matching networks and amplifiers
    (IEEE, 2013) Atilla, Doğu Çağdaş; Aydın, Çağatay; Köprü, Ramazan; Nesimoğlu, Tayfun; Yarman, Bekir Sıddık Binboğa
    Coverage of commercial communication standards such as GSM, UMTS, Wi-Fi and Wi-Max within a single transceiver chip is one of the most desired properties by wireless communication manufacturers. In this regard, communication companies are keenly interested in the design of high power amplifiers for broadband cellular communications to achieve this coverage. In this work, design of broadband tunable matching networks is investigated using Real Frequency Techniques. In practical applications, tunability is needed to compensate for the load impedance variations with environmental effects. In order to be able to work on sample structures, impedance transforming filters with proper topology are chosen and a broadband tunable matching network with a tunability strategy is developed. Eventually a broadband amplifier has been designed using the tunable inductor concept.
  • Küçük Resim
    Yayın
    Design of a new low loss fully CMOS tunable floating active inductor
    (Springer New York LLC, 2016-12) Momen, Hadi Ghasemzadeh; Yazgı, Metin; Köprü, Ramazan; Saatlo, Ali Naderi
    In this paper, a new tunable floating active inductor based on a modified tunable grounded active inductor is proposed. The multi regulated cascade stage is used in the proposed active structure to decrease the parasitic series resistance of active inductor, thus the Q factor enhancement is obtained. Furthermore, the arrangement of this stage leads to the smaller input transistor which determines active inductor’s self-resonance frequency and to be free of body effect which is crucial in sub-micron technology. Symmetrical design strategy has enabled both ports of the proposed floating active inductor to demonstrate the same properties. The Q factor and active inductor value are tuned with bias current and flexible capacitance (varactor), respectively. The self-resonance frequency of floating active inductor (~6.2 GHz) is almost the same as grounded prototype. In addition, the proposed active inductor also shows higher quality factor and inductance value compared to the conventional floating active inductor circuits. To show the performance of suggested circuit, simulations are done by using a 0.18 µm CMOS process, which demonstrates an adjustable quality factor of 10–567 with an inductance value range of 6–284 nH. Total DC power consumption and occupied area are 2 mW and 934.4 µm2, respectively.
  • Küçük Resim
    Yayın
    Designing a new high Q fully CMOS tunable floating active inductor based on modified tunable grounded active inductor
    (Institute of Electrical and Electronics Engineers Inc, 2015) Momen, Hadi Ghasemzadeh; Yazgı, Metin; Köprü, Ramazan
    A new Tunable Floating Active Inductor (TFAI) based on modified Tunable Grounded Active Inductor (TGAI) is proposed. Multi regulated cascade stage is used in TGAI to boost gain of input impedance and inductor value thus the Q factor enhancement obtained. The arrangement of Multi-Regulated Cascade (MRC) stage is caused the input transistor which determines AI self-resonance frequency to be as small as possible and it is free of body effect which is crucial in sub-micron technology. Compared to traditional CMOS spiral inductors, the active inductor proposed in this paper can substantially improve its equivalent inductance and quality factor. This TFAI was designed using the AMS 0.18 um RF CMOS process, which demonstrates an adjustable quality factor of 10?567 with a 6?284 nH inductance. The Q factor and value of active inductor is adjusted with bias current and flexible capacitance (varactor), respectively. The self-resonance frequency for both grounded and floating AI is about 6.2 GHz. The proposed active inductor also shows wide dynamic range and higher quality factor compared to conventional floating active inductor circuits.
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    Yayın
    A design technique of 50 Ω terminated bandpass matching network and its implementation to a Y-shaped monopole antenna matching
    (Springer, 2016-12) Aydın, Çağatay; Atilla, Doğu Çağdaş; Köprü, Ramazan; Kılınç, Sedat; Karakuş, Cahit; Yarman, Bekir Sıddık Binboğa
    In this paper, a 50 Ω terminated or in other words transformerless bandpass matching network design methodology and an implementation example are presented. The real frequency techniques are powerful numerical methods to design wideband lossless two-port networks such as filters, matching networks and amplifiers. In these techniques, the value of the termination resistance of the designed network could not be yielded as 50 Ω by numerical package. Hence, a transformer is also required for 50 Ω termination which is not practical for high frequency applications. By employing the proposed procedure, it is guaranteed to obtain transformerless bandpass matching network. Also in this study a wideband suspended monopole antenna is examined. The proposed antenna consists of two major elements; Y-shaped impedance matching plate and hemi-circular radiator. Moreover Y-shaped impedance matching plate connected to a feeding probe excites the suspended hemi-circular radiator via air gap. Consequently, a transformerless bandpass matching network is designed to filter and expand the operational frequency bandwidth of the proposed antenna. It has been observed that ideal circuit and the layout of the matching network simulation have good agreement.
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    Yayın
    A novel method to design wideband power amplifier for wireless communication
    (IEEE, 2013) Köprü, Ramazan; Kuntman, Hulusi Hakan; Yarman, Bekir Sıddık Binboğa
    A new approach is presented to design microwave amplifiers to deliver maximum output power using Simplified Real Frequency Technique (SRFT). Proposed method tracks the maximum stable gain (MSG) curve of the active device (BJT, FET etc.) under consideration. Maximum Stable Gain Amplifier (MSGA) possesses higher gain than that of the constant or Flat Gain Amplifier (FGA) along the operating frequency band. Compared to FGA, it is this feature that makes MSGA high efficiency and low DC power consumption amplifier. Employing the proposed design method, a MSG power amplifier is constructed over the frequency band of 800-5200 MHz which can be utilized for GSM, UMTS, Wi-Fi and Wi-MAX applications.
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    Yayın
    Mixed element wideband microwave amplifier design via simplified real frequency technique
    (IEEE Computer Society, 2014) Kılınç, Sedat; Köprü, Ramazan; Aksen, Ahmet; Yarman, Bekir Sıddık Binboğa
    In this study, we illustrate the design and implementation of a wideband microwave small-signal amplifier composed of mixed elements. The design is based on Simplified Real Frequency Technique (SRFT). A design of low power amplifier circuit is completed and its simulations are performed in success. The circuit is designed with lumped elements, however, some of the lumped elements are converted to distributed elements for their convenience in production. In this way, a mixed element wideband microwave amplifier comprised of input/output matching networks with lumped and distributed elements has been formed. Layout work and also post layout simulation is given with satisfying results.