Papers by Siddik B Yarman
Yükseköğretim dergisi, 2011
Üniversitelerin esas amaçlar› seküler dünya görüflü çerçevesinde elefltirel ak›l, yarat›c›l›k ve ... more Üniversitelerin esas amaçlar› seküler dünya görüflü çerçevesinde elefltirel ak›l, yarat›c›l›k ve beceriyi, bu-lunduklar› toplumda ve uluslararas› düzeyde evrensel boyutlara tafl›mak, ulusal ve uluslararas› rekabete açmakt›r. Bu ba¤lamda çeflitlilik, kurumsal özerklik ve hesap verebilirlik 3 temel ö¤edir. Yüksek ö¤retimi düzenleyecek yasa çerçeve niteli¤inde olmal›d›r.
5W Linear Power Amplifier Design for 5 – 6 GHz Applications
2022 30th Signal Processing and Communications Applications Conference (SIU), May 15, 2022
Electrica, Mar 5, 2019
Prediction models provide the probability of an event. These models can be used to predict diseas... more Prediction models provide the probability of an event. These models can be used to predict disease's outcomes, reccurencies after treatments. This paper presents an expert system called Symptom Based Clinical Decision Support Tool (SBCDST) for early diagnosis of erythemato-squamous diseases incorporating decisions made by Bayesian classification algorithm. This tool enables family practitioners to differentiate four types of erythematosquamous diseases using clinical parameters obtained from a patient. In SBCDST, Psoriasis, Seborrheic Dermatitis, Rosacea and Chronic dermatitis diseases are described by means of well-classified set of attributes. Attributes are generated from the typical sign and symptoms of disorder. Based on our clinical results, tool yields 72%, 93%, 89% and 95% correct decisions on the selected dermatology diseases respectively. System proposed will provide the opportunity for early diagnosis for the patient and the expert medical doctor to take the necessary preventive measures to treat the disease; and avoid malpractice which may cause irreversible health damages.
Zero-IF Second Harmonic SiGe Mixer with DC Offset Cancellation
IU-Journal of Electrical & Electronics Engineering, Apr 27, 2016
In this work, a new SiGe mixer circuit topology operating with the second harmonically pumped mix... more In this work, a new SiGe mixer circuit topology operating with the second harmonically pumped mixing technique is proposed. The proposed circuit is developed for to be used in IC receivers which use Zero-IF mixers at their front ends. The Analysis of the circuit is performed and the appropriate operation conditions for second harmonically pumped mixing are investigated. The topology is quite suitable for the wide band applications and has a unique mechanism to prevent the LO to RF leakage which results in DC offset at the output. Simulations are performed and according to the simulation results, 21dB of conversion voltage gain is obtained within 2-12 GHz RF range while the DC voltage component at the output stays more than 80dB below the IF component.
Design of 50-Watt 2-Stage Class-F Power Amplifier for Medical Applications
In this work, a high power high efficiency and high gain class-F power amplifier with low harmoni... more In this work, a high power high efficiency and high gain class-F power amplifier with low harmonic content was designed and simulated by using CGH40010F and CGHV40050F Gallium Nitride transistors and NI AWR Microwave Office for electromedical and radar applications. According to the simulation results, 47.5 dBm output power, 73% efficiency and 22 dB gain values were obtained in the 2.7-2.9 frequency band.
In this paper, a variable-speed rotary compressor controller was developed by using low-cost high... more In this paper, a variable-speed rotary compressor controller was developed by using low-cost high performance digital signal controller. Sensorless control of compressor's interior permanent magnet synchronous motor is obtained using fundamental excitation method. Start-up, rotor alignment, merging, position and speed estimation algorithm was explained. Developed system was tested with a loaded rotary compressor that is the part of a heat-pump system and experimental results were presented.
IEEE Transactions on Microwave Theory and Techniques, Oct 1, 2012
I would like to express my special gratitude to Prof. Dr.-Ing. Rolf H. Jansen, the head of the Ch... more I would like to express my special gratitude to Prof. Dr.-Ing. Rolf H. Jansen, the head of the Chair of Electromagnetic Theory (ITHE), RWTH Aachen University, for giving me the opportunity and the freedom to complete my Ph.D research under his supervision. Also, I would like to thank him for supporting me with the insight in academic aspects and the fruitful discussions. I am grateful to Prof. Dr.-Ing. Dirk Heberling to be co-referee and Prof. Ernesto Limiti as an external examiner for my thesis examination. In addition, I am grateful to Motorola Education Assistance Board (Lee SiewYin, Fam FookTeng, Dr. Hari Narayan, Chacko Prakash, and the team) for providing financial support. Special thank to Prof. Claudio Paoloni for his help in reviewing my thesis and provide comments. Also, sincere gratitude to Fam FookTeng, Chacko Prakash and Joey Ooi (Motorola Research Center, Florida, US) for their encouragement and motivation given during my work. My sincere gratitude extends to my parents, beloved wife and all my colleagues and friends for their kind assistance and support, including Aridas, Indra
An Adaptive Modulation for Relay-Assisted Wireless Optical Network
This paper investigates the relay effects on band-width efficiency. The investigation considers t... more This paper investigates the relay effects on band-width efficiency. The investigation considers that the relay terminals are serially placed between the transmitter and the receiver terminals. The investigation considers that the transmitter terminal possesses the channel state information and also considers log-normal fading channel for the performance analysis. Based on the channel conditions, the transmitter adjusts the modulation sizes in each slot by using the channel state information. During the adaptive transmission, the peak power constraint is addressed to provide eye safety. Results show that the proposed adaptive modulation system significantly enhances bandwidth efficiency in comparison to the non-adaptive system.
Multiband filter design from bandpass prototype filter with using frequency transformation via SRFT
2016 National Conference on Electrical, Electronics and Biomedical Engineering (ELECO), Dec 1, 2016
Multiband filter design problem includes both analytical and implementation aspects. The main int... more Multiband filter design problem includes both analytical and implementation aspects. The main interest is defining a Transducer Power Gain (TPG) function characteristic over frequency bands. It is demanded to suppress or amplify the TPG at certain frequencies. In this study a new method is presented for creating the multiband response with using well defined analytical approach. A transformer-less bandpass filter prototype is synthesized with using well known Simplified Real Frequency Technique (SRFT) and multiband characteristic is derived with applying a basic frequency transformation on the bandpass prototype filter. A double band filter design example is prensented. Descriptive functions of each sections are given in scattering polynomail form. Certain advantages are provided with using this method besides the sequential application of basic low pass to band pass transfromation on a low pass transfer function such as low counts of elements, controlling the filter roll off, easy conversion to distributed domain without probable parasitic couplings.
Fen ve mühendislik bilimleri dergisi, Jun 30, 2022
Anahtar kelimeler Covid-19; Akciğer bt bulguları; Boruta; Buzlu cam opasitesi; Kondolidasyon; Kal... more Anahtar kelimeler Covid-19; Akciğer bt bulguları; Boruta; Buzlu cam opasitesi; Kondolidasyon; Kaldırım taşı paterni Öz Covid-19 pandemisi nedeniyle milyonlarca insan hayatını kaybetmiş ve birçok ülkede yetersiz sağlık sistemleri hizmet veremez hale gelmiştir. Covid-19 hastalarının yoğun bakım ve ventilasyon ihtiyaçlarının belirlenerek hastalığın prognozu hakkında tahminlerde bulunulması, hastanın sağlık durumu ve sağlık sistemlerinin etkin kullanımı açısından önemlidir. Bu amaçla oluşturulan Covid-19 akciğer bilgisayarlı tomografi (BT) bulguları veri seti buzlu cam opasitesi, konsolidasyon, kaldırım taşı paterni, konsodilasyon ve buzlu cam, nodül ve buzlu cam sınıflarını içermektedir. Bu çalışmada önerilen yaklaşım dört adımdan oluşmaktadır. Birinci adımda VGG-16 modeli akciğer BT bulguları veri seti ile eğitilmiştir. İkinci adımda elde edilen en ayırt edici öznitelikler BORUTA algoritması kullanılarak seçilmiştir. Üçüncü adımda sıralama yöntemiyle her görüntü için en değerli ilk 200, 300 ve 400 öznitelikler elde edilmiştir. Son adımda ise Destek Vektör Makineleri ve Lineer Diskriminant Analizi ile bu özellikler sınıflandırılmıştır. Akciğer BT bulguları veri seti için elde edilen genel doğruluk %97,02'dir. Derin Öğrenme yöntemleri ile Covid-19 hastalık prognozunu tahmin etmek için oluşturulan veri seti kullanılarak elde edilen bu başarılı sonuç, viral pnömoni türlerinin akciğer BT bulgularının sınıflandırılmasında çok önemli bir yeniliktir.
A Realizability Test as Applied on the Generated Source/Load-Pull Data
2022 Microwave Mediterranean Symposium (MMS), May 9, 2022
A frequency transformation based real frequency design approach for dual-band matching
This work describes a real frequency design approach for dual-band matching networks. The propose... more 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.
IEICE Electronics Express, 2013
In this study, balanced and single ended class-E power amplifiers (PAs) were designed and realize... more In this study, balanced and single ended class-E power amplifiers (PAs) were designed and realized for 3.5-3.8 GHz band by using Gallium Nitride high electron mobility transistor (GaN HEMT). Realizations were made on low loss Rogers RT5880 dielectric material which has 0.254 mm thickness and 2.2 dielectric constant. Proposed balanced class-E PA has approximately 20 W (43 dBm) output power with 80% peak power added efficiency (PAE) and shows a very favorable combination of output power, PAE and suppressed even order harmonics compared to the single ended class-E PA prototype.
A Numerical Approach for the Design of Matching Networks Consisting of Brune Sections Based on Fujisawa Constraints
In this study, the realization problem of matching network consisting of Brune sections is invest... more In this study, the realization problem of matching network consisting of Brune sections is investigated. In the synthesis of a general impedance function with finite transmission zeros, each transmission zero extraction results in a Brune section involving a negative reactive element. Although coupled inductances can be used to remove negative elements, a direct mutual coupling free ladder design is aimed by properly incorporating the mid-shunt ladder realizability conditions of Fujisawa. For this purpose, impedance based Real Frequency Technique (RFT) is used to construct realizable impedance function and Fujisawa synthesis procedure is applied for mid-shunt ladder realization. An illustrative matching network design example is presented.
Design of impedance matching network for B&K 8104 hydrophone via Direct Computational Technique for underwater communication
A Numerical Procedure to Determine the Power Intake/Delivery Capacity of a GaN RF Power Transistor over Broadband
2022 Microwave Mediterranean Symposium (MMS), May 9, 2022
IEICE Electronics Express, 2017
An ultra-wideband power amplifier (PA) design employing Real Frequency Technique (RFT) with Galli... more An ultra-wideband power amplifier (PA) design employing Real Frequency Technique (RFT) with Gallium Nitride high-electron-mobilitytransistor (GaN HEMT) technology is presented. The practical implementation was done with combination of distributed and lumped elements (mixed lumped elements combination) for the need of industrial requirements for the small form factor and low cost. This is an attractive approach for Software Defined Radio (SDR) products to meet wide bandwidth range of 80-2200 MHz. The measured results of the prototype reported good performance over the bandwidth of the interest (i.e. power of 34 dBm to 43 dBm, efficiency about 39% to 69% and gain in the range of 11 dB to 18 dB), and reasonable agreement with the simulated data. According to author's knowledge, these results are significant for single-ended GaN HEMT device for the wideband operation starting from low frequency 80-2200 MHz.
Dual band matching network design via real frequency technique by mapping from a band pass prototype
In this study, a new method of design for dual band matching network is presented. A transformer-... more 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.
A Gysel Power Combiner with 20W Wideband Isolation Termination and 25% Fractional Bandwidth
2021 13th International Conference on Electrical and Electronics Engineering (ELECO)
In this paper, a Gysel power divider with 2.5 GHz center frequency and 40% fractional bandwidth w... more In this paper, a Gysel power divider with 2.5 GHz center frequency and 40% fractional bandwidth was designed for use in high-frequency high-power circuits. Rogers RT5870 with dielectric constant of 2.33, dielectric thickness of 0.787 mm, copper thickness of 35 µm and loss tangent of 0.0005 was used as the dielectric substrate. Vishay FT10302N0050J termination was used as isolation resistor in the study. According to the simulation results, the Gysel power combiner designed has a maximum insertion loss of 0.1 dB, amplitude imbalance of 0.05 dB and phase unbalance of up to 0.2 degree over the 2.2-2.8 GHz band. Since the layouts of the microstrip lines were created by paying attention to the high frequency design principles, meaningful difference was not observed between the circuit and electromagnetic simulation results. When the actual circuit is measured, a insertion loss of up to 0.2 dB over the 2.2-2.8 GHz band, an amplitude imbalance of up to 0.1 dB between the input ports and maximum 1 degree phase imbalance results were obtained. Since isolation resistor has an impedance of about 50 Ohm and a power resistance of 20W throughout the DC-18 GHz band, the implemented power combiner can be used to obtain higher output powers by combining 20 Watt and above power amplifier circuits.
Uploads
Papers by Siddik B Yarman