Browsing by Subject "Power amplifier"

Now showing 1 - 6 of 6

Open Access
Design of an X-band GaN based microstrip MMIC power amplifier
(2019-02) Özipek, Ulaş
RF power amplifiers are crucial components of modern radar and communication systems. However, their design poses some challenges due to device limitations in high power and high frequency regime, as well as inherent difficulties of designing for nonlinear large-signal device operation. Gallium Nitride (GaN) based High Electron Mobility Transistors (HEMT) are promising candidates due to their superior material qualities, high power densities and ability to operate up to mm-wave frequencies. In this thesis, 0.25 μm GaN on SiC microfabrication process of Bilkent University Nanotechnology Research Center (NANOTAM) is presented. Transistor characterization procedure is demonstrated. Ideal transistor layout for design goals is selected and the transistor gate structure is optimized for X-band performance. A model library for microstrip passive circuit elements based on electromagnetic simulations has been developed. Finally, design and measurements of an X-band microstrip Class AB two-stage Monolithic Microwave Integrated Circuit (MMIC) PA, based on the same process are presented in detail. With die sizes smaller than 4.3 mm by 2.3 mm, fabricated MMICs operate at 8.5 - 11.5 GHz band with 24 dB small-signal gain. More than 13.5 W (41.3 dBm) output power (P6dB) and 31 - 38 % power-added efficiency are achieved throughout the 8.5 - 11 GHz band in pulsed mode on-wafer measurements.
Open Access
High efficiency 35 GHz MMICs based on 0.2 μm AlGaN/GaN HEMT technology
(Cambridge University Press, 2022-06-16) Akoğlu, Büşra Çankaya; Sütbaş, Batuhan; Özbay, Ekmel
In this paper, two high efficiency monolithic microwave integrated circuits (MMICs) are demonstrated using NANOTAM's in-house Ka-band fabrication technology. AlGaN/GaN HEMTs with 0.2 μm gate lengths are characterized, and an output power density of 2.9 W/mm is achieved at 35 GHz. A three-stage driver amplifier MMIC is designed, which has a measured gain higher than 19.3 dB across the frequency band of 33–36 GHz. The driver amplifier exhibits 31.9 dB output power and 26.5% power-added efficiency (PAE) at 35 GHz using 20 V supply voltage with 30% duty cycle. Another two-stage MMIC is realized as a power amplifier with a total output gate periphery of 1.8 mm. The output power and PAE of the power amplifier are measured as 3.91 W and 26.3%, respectively, at 35 GHz using 20 V supply voltage with 30% duty cycle. The high efficiency MMICs presented in this paper exhibit the capabilities of NANOTAM's 0.2 μm AlGaN/GaN on SiC technology.
Open Access
A high gain and high efficiency 15 W X-Band GaN power amplifier MMIC
(IEEE, 2019) Gürdal, Armağan; Özipek, Ulaş; Sütbaş, Batuhan; Özbay, Ekmel
An X-band microstrip power amplifier MMIC based on our 0.25 μm AlGaN/GaN on SiC process technology is presented in this work. Fabrication steps, HEMT structure and typical device performance are demonstrated. Design procedure of the three-stage power amplifier MMIC with a compact size of 4.7 mm × 2.7 mm is described. Small-signal measurements of the fabricated MMICs typically show 36 dB gain with 5 dB ripple and input/output return losses better than 16 dB and 7 dB from 8.5 GHz to 12 GHz band, respectively. Typical output power of 15 W at 6 dB compression with 37%-44% power added efficiency is achieved under pulsed operation. MMIC power measurements performed at different base plate temperatures and bias conditions are also provided. This design exhibits significantly higher gain and much better input return loss compared to MMICs in the literature with similar size, efficiency and output power parameters.
Open Access
S-band GaN high power amplifier design and implementation
(2019-02) Kavuştu, Muhammet
High power RF Microwave amplifiers are becoming more important as the telecommunications, defense and aerospace industries' demands develop. GaN on SiC technology offers higher power and better form factors for these applications compared to GaAs. In addition, SiC provides better mechanical properties and thermal performance. Design, manufacturing and measurements of a S-Band Power Amplifier by using a GaN discrete bare die transistor are presented. GaN on SiC technology, fabrication process, amplifier fundamentals and design steps are explained in detail. PCB laminate properties, manufacturing, wire bonding and importance of heat management are explained. Design, tapeout, characterization of a fabricated HEMT and its packaging are also mentioned. Power amplifier's small-signal gain of 14.5 dB is measured at center frequency. 41.5 dBm RF power at P6dB is measured at 200 μs pulse width 10% duty cycle at 3 GHz, reaching a power density of 5:4W=mm. Small-signal gain, IP3 measurements under different biases, AMAM and AM-PM distortions are also investigated in detail. EM simulations are performed in Keysight ADS design environment. Amplifier design is based on small-signal and loadpull measurements. De-embedding of fixture effects during HEMT characterization and their models are also investigated. Another hybrid amplifier design by using a packaged commercial GaN on SiC bare die power HEMT is also presented. Small-signal and power measurements are also offered.
Open Access
X band GaN based MMIC power amplifier with 36.5dBm P1-dB for space applications
(IEEE, 2018) Gürdal, Armağan; Yılmaz, Burak Alptuğ; Cengiz, Ömer; Sen, Özlem; Özbay, Ekmel
An X-Band Monolithic Microwave Integrated Circuit (MMIC) High Power Amplifier (HPA) with coplanar waveguide (CPW) based on AlGaN/GaN on SiC technology is presented in this paper. Coplanar waveguide technology (CPW) is chosen for the simplicity and reduced cost of fabrication since CPW process has no via. High Electron Mobility Transistors (HEMTs) are matched for the 8 GHz-8.4GHz frequency band for maximum output power. The Amplifier has a small signal gain over 10 dB, output power of 36.5dBm at 1 dB gain compression point (P1dB) and 40% power added efficiency (PAE) at (PldB) in the desired frequency band (8 GHz-8.4 GHz) with Vds = 30V.
Open Access
X-band CPW high power amplifier design by GAN based MMIC technology
(2016-06) Yılmaz, Burak Alptuğ
The developments in defense industry, telecommunication and satellite systems have gradually increased the necessities for the small and compact Power Ampli- fiers (PAs) with high output powers and gains. Monolithic Microwave Integrated Circuits (MMICs), that are fabricated by using Gallium Nitride (GaN) on Silicon Carbide (SiC) substrate, achieve the system requirements. GaN based MMIC technology gives chance to produce high power capable and compact PAs. Moreover, suitable Wilkinson Power Dividers (WPDs) with low Insertion Loss (IL) assist in transferring output power of the device with combining MMIC PAs. Presented designs in this thesis work have been fabricated in Bilkent University NANOTAM with GaN on SiC process. Fabricated X-band Coplanar Waveguide (CPW) PA works from 7.9 GHz to 8.4 GHz as intended and its efficiency equals to 40 % at 8.4 GHz under 2.1 dB compression. Measurements of fabricated PA show that output power of the device is equal to 37.8 dBm under 2.1 dB compression and it has 9.8 dB minimum gain in the operating band. Furthermore, equal, three-way WPD device was designed and fabricated with the same process and it works at wide-band range with approximately 0.9 dB IL. It is advantageous that the total dimension of paralleled MMIC PAs can be adjusted by scaling branches of the designed WPD with the aim of performance optimization.