Osman Ceylan

Characterization of devices operating under large signal conditions at nonlinear regions requires specific measurement setups since the output power value, operation efficiency, power gain, and linearity are functions of the source impedance, input signal level, biasing values, and load impedance. Hence, measuring a device’s parameters while varyin...

In this study, we focus on automated optimization design methodologies to concurrently trade off between power gain, output power, efficiency, and linearity specifications in radio frequency (RF) high-power amplifiers (HPAs) through deep neural networks (DNNs). The RF HPAs are highly nonlinear circuits where characterizing an accurate and desired a...

This study provides a comprehensive multi-objective optimization process for enhancing efficiency and minimizing phase distortion concurrently for high power amplifiers (HPAs) using deep neural networks (DNNs). The proposed optimization-oriented strategy consists of two sequential optimization phases: predicting the suitable HPA structure using a c...

This study presents an automated high-accuracy optimization approach for designing high-performance radio frequency high power amplifiers (HPAs). The amplifier is designed by applying a top-down pruning optimization approach that automatically converts the given HPA with lumped elements (LEs) to the HPA with distributed elements (DEs). Firstly, the...

Optimizations have gained much consideration from the researchers working in the domains of analog and radio frequency (RF), recently. Dealing with highly nonlinear behavior of active components and aiming to meet design specifications are common issues in all nonlinear circuit designs. As a consequence and accordingly, many studies have been condu...

Optimizations have gained much consideration from the researchers working in the domains of analog and radio frequency (RF), recently. Dealing with highly nonlinear behavior of active components and aiming to meet design specifications are common issues in all nonlinear circuit designs. As a consequence and accordingly, many studies have been condu...

S-parameter data with uncertainty information are presented in the data set. High power RF transistors are measured with a regular measurement setup, consisting of a VNA, coaxial cables, bias tees, and fixture. Measured transistors are FLL57MK (GaAs-FET), LP601 (LDMOS-FET), CLF1G0060S-10 (GaN-HEMT), T2G6000528-Q3 (GaN-HEMT), CGH40010-F (GaN-HEMT)....

In this data set, a power transistor’s uncertainty added S-parameters, its estimated S-parameters, uncertainty added S-parameters of a power amplifier circuit, uncertainty added S-parameters of a cascaded amplifier, and amplifier’s design files are presented. Sumitomo’s GaAs-FET FLL57MK is used for the measurements and design. Cadence AWR is used f...

This study presents an automated optimization-oriented strategy for designing high power amplifiers (HPAs) using deep neural networks (DNNs). The proposed strategy consists of two optimization phases that are applied sequentially. In the first phase, the circuit topology is optimized by determining the number of passive components in the input and...

This study presents an automated RF power amplifier design procedure and methods which aim to convert systematically built-in lumped elements to distributed elements by simultaneously optimizing power gain, output power and efficiency. This approach which is performed by using Bayesian optimization results in ready-to-fabricate optimized designs wi...

This study describes a design automation methodology and technique for designing an optimized high power amplifier (PA). The proposed method optimizes the matching networks by deriving the suitable matching components and automatically evaluating their performances with nonlinear simulations. The design process starts with a simple cell and then th...

In radio frequency power amplifier designs, the desired current and voltage waveforms are achieved through the tuning of the fundamental and harmonic impedance values in the matching networks. Analytical design methods have been often used to design power amplifiers. But nonlinear behavior of the high-frequency power transistors and inevitable trad...

High data rate mobile communication requires wideband high-frequency circuits and systems. A high power amplifier (HPA) is an essential part of the communication systems and operates at saturation to achieve high efficiency. On the other hand, the design of an HPA is a challenging issue due to the nonlinear behavior of the high frequency and high p...

Linear amplification is an essential need for the transmitters of mobile communication systems using complex modulation schemes due to the required high fidelity phase and amplitude response. In this study, a new dual-stage high gain and efficiency driver amplifier and its linearization performance are presented. The GaN MMIC is implemented without...

Design and optimization of wideband nonlinear RF circuits are time-consuming and challenging design issue. Both electronic design automation (EDA) and numerical analysis tools can be used to design microwave circuits. However, they have different capabilities regarding calculation and optimization processes. In this study, EDA and numerical analysi...

Class-F type amplification stands on proper termination of harmonics such as short for even harmonics and open for odd harmonics. Moreover, termination of only the first few harmonics is practical for high-frequency circuits, while obtaining satisfactory short and open terminations at high frequencies is a challenging design issue. In the present s...

High-frequency active-device performance depends very much on the DC biasing conditions. For optimum performance, a solid-state device (SSD) requires an application-specific biasing network. Such bias networks are not only essential parts of RF/microwave circuits with SSDs, but properly designed bias networks contribute a great deal to the performa...

The demand for very high data rate 5G systems requires the use of wider spectrum bandwidths and phased array systems to increase the network capacity. Although the individual power level of each RF amplifier decreases due to the array factor, in the sub-6GHz bands it is still high enough to place significant challenges on its development, to fulfil...

In this paper, we show that low-voltage operation of a GaN transistor (5.5V) as a driver allows very high line-up efficiency, including driver and end-stage. We realized two-stage MMIC in 0.25pm GaN HEMT technology. The MMIC die and high harmonic matching circuits were assembled into a standard ceramic RF package. The load-pull measurement results...

Software defined radios provide flexible and improved communication systems due to digitally controlled signal processing. In this paper, development details of a software defined transmitter for a Cube-Satellite are presented. Proposed transmitter can work as a digital radio transmitter and satellite beacon. Radio modem transmitter is able to gene...

Bu calismada, yazilim tanimli radyo tabanli karma yapili FM demodulator Sahada Programlanabilir Kapi Dizileri (FPGA) uzerinde gerceklenmis ve test edilmistir. Tasarimda kullanilan tum alt moduller donanim tanimlama dili olan VHDL ile tasarlanmistir Yazilimsal uygulamalarda onemli olan esneklik, kaynaklarin verimli kullanimli ve dusuk guc tuketimi k...

Optik haberleşme sistemleri, yüksek hızda veri iletişimi sağladığı için günümüzde yoğun olarak kullanılmaktadır. Ancak optik işaretlerin taşıdığı veriyi işleyebilmek için optik işaretin elektriksel işarete çevrilmesi gereklidir. Bu çalışmada, optik işareti elektriksel işarete çeviren bir devre sunulmuştur. Tasarlanan devre dengeli girişe sahip olup...

Bu çalışmada, yazılım tanımlı radyo tabanlı karma yapılı FM demodülatör Sahada Programlanabilir Kapı Dizileri (FPGA) üzerinde gerçeklenmiş ve test edilmiştir. Tasarımda kullanılan tüm alt modüller donanım tanımlama dili olan VHDL ile tasarlanmıştır Yazılımsal uygulamalarda önemli olan esneklik, kaynakların verimli kullanımlı ve düşük güç tüketimi k...

This article presents both a four-element novel microstrip array antenna and a low noise amplifier (LNA) for a Ku-band small satellite receiver. It includes all design details with measurement results of the fabricated array antenna and LNA. Measured minimum and maximum gains of the proposed antenna are 10.1 and 10.9 dBi in 11.9{12.9 GHz band frequ...

The space race has played a significant role in the history of the last half century, and satellites are among the most important parts of space race and technology. More than 6,000 artificial satellites have been deployed since the first, Sputnik, in 1957; some 1,000 are still in operation. When most people not involved in satellite technologies s...

Signal sources are essential devices for radar and communication systems. The demand for oscillators has existed for very long time. In 1888, Heinrich Hertz introduced the first known oscillator to prove Maxwell's equations experimentally [1]. He used a dipole as the frequency determining structure and a spark-gap generator as the signal source. Hi...

Cube satellites (known as university satellites) are very popular in these days since, they can be designed easily and with low cost. In order to communicate with these satellites, instead of using traditional analog radio modems, Software Defined Radio (SDR) modems are preferred for many advantages. In this project, a SDR modem for satellite and a...

ZET Bu çalışmada X bandında çalışan, yüksek verimli F sınıfı güç kuvvetlendiricisi Galyum Nitrit Yüksek Elektron Hareketlilikli Tranzistor (High Electron Mobility Transistor, GaN tHEMT) kullanılarak tasarlanmıştır. Bu tasarımda kullanılan Triquint TGF2023-1-01 tranzistoru için Modelithics geliştirdiği doğrusal olmayan tranzistor modeli kullanılmışt...

Despite the small amount of available volume, CubeSat missions have proven to be quite useful, especially for scientific data gathering, educational purposes and small scale industrial equipment testing. The aim of this article is to discuss the design principles and project goals of a CubeSat that is part of the QB50 project. HAVELSAT is a double-...

Bu çalışmada 2.45 GHz'de çalışan dairesel polarizasyonlu bir anten dizisi tasarlanmıştır. Bu tip bir anten çoğunlukla deneysel amaçlı küçük uydular ile haberleşme amacı ile yer istasyonunda kullanılmak üzere tasarlandığından sistemin yüksek kazanç gereksinimini sağlamalıdır. Birkaç km yüksekliğe ulaşan deneysel amaçlı küçük uyduların kararsız harek...

A high-speed downlink communication system is required to meet various applications for nano/small satellites. The purpose of this research is to develop a high-data-rate X band downlink system with low power consumption. A high efficient RF circuits using GaN-HEMT SSPA and low power consumption digital circuits were important. We developed over 30...

Nano satellites are generally developed by universities for scientific researches because of low design cost and time. On the other hand a nano satellite has small power and limited volume; therefore there are several restrictions for circuit design. In this project, a digitally controlled VHF to UHF analog transponder is presented for nano satelli...

A high-speed downlink communication system is required to meet various applications for small satellites. The purpose of this research is to develop a high-data-rate (typically over 300Mbps) communication system. Generally, the operation at nonlinear region provides high efficiency for a RF power amplifier. However the amplitude-phase modulated sig...

A high-speed downlink telecommunication system is required to meet various applications for small satellites such as earth observation. The purpose of this research is to develop a high-data-rate (typically over 300Mbps) communication system. Generally, the operation at nonlinear region provides high efficiency for a RF power amplifier. However the...

Nano satellites are generally developed by universities for scientific researches because of low design cost and short design period. A nano satellite has independent subsystem that have to be controlled properly and efficiently via an on board computer. However, a nano satellite has small power and volume for circuits so designer has some restrict...

In recent years, small satellites have begun to draw attention due to reconstruction in low cost of manufacture and faster building time. In this project, radio transmitter system is built for nano and micro satellites. Transmitter broadcasts 1W power in 435 MHz free amateur satellite communication band, and also has software defined radio structur...

In this paper, implementation of a FPGA-based and VHDL coded reconfigurable frequency shift keying (FSK) modulator for nano-satellite communication systems is presented. Reconfigurable FSK modulator includes 2-FSK and 4-FSK modulators. The system is compatible with AX.25 data link layer protocol for general amateur radio communication which is popu...

In this paper, free space path loss, ray tracing with one and two reflection points and logarithmic distance path loss models are used to determine distance between nodes according to RSSI values. First of all, required parameters to use called models are determined by making RSSI characterization study in corridors. Then determined parameters are...

Signal combiners are an important part of high frequency electronics. Generally in higher frequencies, antennas have large bandwidths and lots of systems need a single antenna. In order to combine different frequencies, traditional power combiners such as Wilkinson, Hybrid Coupler etc. are not efficient. In this paper, a 3 bands combiner (triplexer...

Nano satellite structures have limited communication ability due to limited power and size. Most of satellite includes sensors, for instance camera, also image transfer requires more data transfer speed. In this project, 2.4 GHz (S Band) communication system is designed for LEO satellites (700-900 km). System includes system-on-chip transmitter dev...

In this paper, the construction of GMSK modulated SDR ( Software defined radio ) design which could be processed in nano-satellites is discussed. A Gaussian FIR filter which is controllable and has the coefficients arranged with different BT values (0.3, 0.5, 0.7, and 1.0) has been formed. After the filter which works on the Cyclone II FPGA has bee...

In this paper, a 435 MHz monopole antenna for Turksat-3USAT project is designed and manufactured by using HFSS design tool. Antenna should be winded up to be closed during launch. Beryllium-copper alloy is preferred as material due to high durability. Length of λ/4 monopole antenna is determined as 0.257*λ for 435 MHz (177.5mm) with regard to simul...

This study is motivated by the project " TURKSAT – 3USAT " which is a 3U nano satellite in dimensions of 10 cm x 10 cm x 30 cm in order to constitute wireless communication. TURKSAT – 3USAT has 145.8 MHz uplink and 436.8 MHz downlink frequencies. Transponder consists of an LNA stage, filters, mixers and an AGC (Automatic Gain Control) block. Output...

In this work, 3D localization is produced by utilizing ultrasonic and radio signals at wireless sensor network and for this purpose time difference of arrival is used for localization. Measurement system is designed by using four hardwares (nodes) which have the same properties. One of the nodes is moving, other three nodes perform as references. T...

A three unit CubeSat called TURKSAT-3USAT is being developed for voice communication at low earth orbit. The payload consists of two VHF/UHF transponders operating at amateur bands. All other subsystems are also doubled for redundancy. Where possible, both COTS systems and in-house development is employed. The energy is provided using super capacit...

In this paper, we initially present RSSI vs Distance test results performed indoor and outdoor with Texas Instruments CC2431 Development Kit. In addition, Location Engine of Development Kit performance is presented with 3 and 4 reference nodes. An alternative algorithm based on Cayley-Menger Determinant, proposed by M.Cao, B.D.O. Anderson and A.S....

This poster presents handmade equipments of Turkiye's first TV channel Istanbul Technical University TV. ITU TV was founded in 1958. Many of the equipments were designed by students as graduation projects and instructors. RF and sound mixers, power amplifiers, antenna, equalizer, comparator, oscillators, coder and power supply are the most importan...

This paper is related to Turkiye's first TV channel Istanbul Technical University TV's born and contribution to Turkish TV broadcasting. ITU TV was setted up as a laboratory in March 1952. Chair of the High Frequency Department, Prof. Dr. Mustafa Santur and his student Assistant Proffesor Adnan Ataman were the constitutive of the ITU-TV. ITU-TV is...

Bu çalışmada Chebyshev tipi alçak geçiren ve yüksek geçiren süzgeçlerle VHF – UHF işaret birleştirici tasarımı ve ayrık elemanlarla gerçeklenmesi yapılmıştır. İşaret birleştiriciler farklı frekanslarda çalışan iki yapıyı ortak bir terminal ile birleştiren yapılarldır [1]. VHF işaretleri seçmek için kesim frekansı 170 MHz olan 5. dereceden bir cheby...

Bu çalışmada 2.4 GHz’de çalışan karesel yarıklı mikroşerit yama anten kullanılarak, anten dizisinin tasarımı ve tasarlanan anten kullanılarak insansız hava taşıtlarından video işareti aktarımı anlatılmaktadır. Mikroşerit antenler boyutlarının küçüklüğü ve düşük maliyetleri nedeniyle RF uygulamalarında tercih edilen yapılardır. Anten dizisi öncelikl...

Bu çalışmada yüksek güç FM alıcı/vericiler için Gysel tipi eşit güç bölümlü üç yollu güç bölücü tasarımı anlatılmıştır. Benzetimler AWR DE (AWR Design Environment) yazılımında yapılmıştır. FR4 taban üzerine yapılan çalışma ile çok yollu güç bölücülerin taban malzemeleri üzerine yapılarak daha düşük maliyetli olarak gerçeklenmesi sağlanmıştır. Çalış...

Bu çalışmada 500MHz - 900MHz aralığında çalışan ön kuvetlendiricili güç kuvvetlendiricisi tasarlanmış ve gerçeklenmiştir. Tasarım ve benzetimler AWR DE (AWR Design Environment) yazılımında yapılmıştır. Tasarımda transistörlerin kararlılık analizinin yapılmış, en verimli güç aktarımının sağlanabilmesi için gerekli katlarda mikroşerit hatlarla empeda...

In this study, an ultra wideband power transfer network is designed by using Real Frequency Technique to use single microstrip antenna with the TI CC1110. CC1110 is a Texas Instruments' transceiver device which supports 3 different frequency (315, 433 and 868 MHz) for communication. Device output is balanced and has different output impedances at d...

Çalışmada 2.4 GHz telsiz haberleşme sistemleri için mikroşerit-dipol antenler farklı fiziksel özelliklere sahip tabanlar kullanılarak tasarlanmıştır. Tasarımlarda temel mikroşerit dipol yapısı korunmuştur. Antenlerin benzetimleri Ansoft HFSS benzetim yazılımında yapılmıştır ve bu benzetimler incelenerek taban kalınlığı, kayıp tanjantı ve dielektriğ...

Bu çalışmada telsiz sensör ağlarında konum belirleme ve izleme, erişim zamanı farkı ölçümü yöntemi ile yapılmıştır. Çalışmada radyo işareti ve ultrasonik işaret kullanılmıştır. Çalışmada radyo işareti ve ultrasonik işaret kullanılmıştır. Donanımların haberleşme frekansı 2.4 GHz, ultrasonik işaret frekansı da 40 kHz'dir. Sistem aynı özellikteki 5 ad...

Bu bildiride, alınan sinyalin güç göstergesinden yararlanarak konumlama uygulamaları için kullanılan CC2431 ZDK geliştirme kitinin içindeki konumlama motorunun hassasiyeti sunulmaktadır. İlk olarak, uzaklık ve güç göstergesinin grafiği çıkartılmış, daha sonra konumlama motoru ile Cayley-Menger determinantına dayanan merkezi konumlama algoritması ha...