Oguzhan Kizilbey

3.5-3.8GHz class-E balanced GaN HEMT power amplifier with 20W Pout and 80% PAE

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.

Design of class-E GaN HEMT power amplifier using elliptic low pass matching network with 86% efficiency

In this paper, a highly efficient prototype of Gallium Nitride high electron mobility transistor (GaN HEMT) power amplifier using elliptic low pass filter output network is proposed, fabricated and measured. A fifth-order elliptic low-pass filter network is designed and implemented for the output matching, which provides optimized fundamental and harmonic impedances. Simulation and experimental results show that a Class-E PA is realized from 2.7 to 2.9GHz with 10-W (40dBm) output power, 10 dB gain and a measured efficiency of 86%, which is the highest reported today for such a frequency band and output power.

A new approach for the design of class-E GaN power amplifier with high efficiency

A high efficient GaN HEMT power amplifier with a new topology is presented for to be used at 3.4-3.7 GHz band. Short sections of the Microstrip-lines are used as harmonic traps at the load network in order to improve the efficiency. The fabricated GaN HEMT amplifier delivers 37.5 dBm saturated output power and the maximum power-added efficiency of 80% and a maximum drain efficiency of 83% are obtained at 3.6 GHz. These values represent the state-of-the-art performance efficiencies at S-Band.

A comparison of GaN, Si and GaAs power amplifiers

Power amplifiers (PAs) are used in the wide range of electronics such as RADAR, base stations, jammers and cable TV applications. These amplifiers can achieve design specifications like high efficiency and high output power (>20 W) as much as the capability of the transistor. For this reason; Si LDMOSFETs, GaN HEMTs and GaAs HFETs are advancing their place in the market. In this article; GaN, Si, and GaAs power transistor technologies will be compared and an assessment will be made about which one is leading the market by 2014.

A miniaturized wideband 180° hybrid ring coupler

In this letter, a compact 3 dB 180°· hybrid coupler was proposed, designed, fabricated and measured. This device was derived from the classical hybrid ring coupler whose 3λ/4 section was replaced with inverting suspended microstrip line (SML). The proposed structure has a reduced size compared with the conventional and enhanced variants of the 3 dB 180° hybrid coupler topologies. Moreover, the new architecture has a greatly improved bandwidth. The measured 0.5 dB insertion loss bandwidth is over the 2-5 GHz band. Because of its symmetrical architecture, the proposed hybrid shows frequency independent balance performance. The maximum of 0.5 dB amplitude imbalance and 5° phase imbalance measured over frequency band of 2-5 GHz. Measured port isolation is also about 40 dB at the center frequency. Compared with other available coupler structures, this coupler has 20% wider bandwidth and 40% smaller sizes without any significant performance degradation.

2–10 GHz multisection 2-way Wilkinson power divider with enhanced port match and isolation

This paper presents two broadband Wilkinson power dividers (WPDs) using single layer microstrip lines. Operation of these WPDs from 2 GHz to 10 GHz could be achieved by using multisectional structure. Presented WPDs have 6 sections and differ in the size of the isolation resistors which have size of 0402 and 0603. For experimental verifications two devices were fabricated and the measurement results match with the simulation results well. Measurement results of the two independent samples show a bandwidth from 2 GHz to 10 GHz with an insertion loss of lower than 0.4 dB, isolation of greater than 25 dB, amplitude and phase imbalance of lower than ±0.3 dB and ±3°, respectively. The realized WPDs exhibit better matching, isolation and phase/amplitude imbalance compared with other wideband power dividers published so far.

Design and realization of different microstrip low pass filter topologies by aid of AWR microwave office ifilter wizard

In this work; 7th order Butterworth, Chebyshev, Cauer (elliptic), Bessel, Legendre and Gaussian low pass filters designed, simulated, realized and measured with aid of iFilter tool of AWR Microwave Office. First, all the filters were designed with lumped L-C elements. Secondly, all lumped components were converted to the microstrip lines as series lines and shunt stubs. All microstrip line widths and lengths were optimized with AWR simulation tool. Comparisons in terms od insertion loss between simulation results of designed lumped filters and measurement results of realized distributed (microstrip) filters show that, distributed filters can be easily optimized by changing widths and lengths of lines without any performance degradation.

A novel broadband compact 3dB 180° power divider/combiner derived from the Wilkinson power divider/combiner

In this paper, a novel 3 dB 180° power divider/combiner is proposed. This device is derived from the classical Wilkinson divider/combiner whose output ports were combined with inverting and non-inverting suspended microstrip lines (SMLs). The proposed structure has a reduced size compared with the conventional and enhanced variants of the 3 dB 180° divider/combiner topologies. Moreover, the new architecture has a greatly improved bandwidth. The measured 0.5 dB insertion loss bandwidth is over the 2-5 GHz band for power combining/dividing. Because of its symmetrical architecture, the presented device shows frequency independent power dividing/combining balance performance. The maximum of 0.5 dB amplitude imbalance and 3° phase imbalance measured over frequency band of 2-5 GHz. Measured port isolation is also about 50 dB at the center frequency.

A novel inverse class E power amplifier topology

In this work, a 10 Watt inverse class-E power amplifier has been proposed, simulated, realized and measured for the 2.7-2.9 GHz wireless applications. In the proposed power amplifier topology distributed elements were used instead of lumped elements and their widths and lengths were optimized with AWR Microwave Office. The new architecture showed 80% power added efficiency and 10W output power during the measurements. All of the harmonics up to 5th are 40 dB lower than the fundamental component. These measurement results are the highest reported in the literature over the 2.7-2.9 GHz frequency band so far.

Design and investigation of 12–50 Ohm tunable microstrip impedance transforming filter

In practical applications, compensating the changes in transistors input and output impedances due to environmental and thermal effects requires tunable matching networks. Having tunability property is critical in manufacturing as well, since manufacturing errors may be compensated by post-production tuning. In this paper, a 12-50 Ω impedance transforming filter over 800-2200 MHz frequency band is chosen and a broadband tunable matching network has been designed using Real Frequency Direct Computational Technique.