scholarly journals Full-Band Oversized Turnstile-Based Waveguide Four-Way Power Divider/Combiner for High-Power Applications

Electronics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 193
Author(s):  
Juan Cano ◽  
Franco Di Paolo ◽  
Angel Mediavilla ◽  
Paolo Colantonio
Keyword(s):  
High Power ◽  
Rectangular Waveguide ◽  
High Efficiency ◽  
Maximum Output Power ◽  
Variable Number ◽  
Power Divider ◽  
Electrical Performance ◽  
Maximum Output ◽  
Relative Bandwidth ◽  
Full Band

Very high-power and high-efficiency microwave applications require waveguide structures to combine/divide the power from/to a variable number of high-power solid-state devices. In the literature, among the different waveguide configurations, those capable of providing the maximum output power show a limited relative bandwidth. To overcome this limitation, in this paper a full-band (40%) waveguide power divider/combiner specifically designed for high-power applications (up to several kW) is presented. The proposed structure uses an evolved turnstile junction with a standard rectangular waveguide common port, rotated 45°, with respect to its central axis, to divide/combine the signal to/from the four output/input rectangular ports. The inclusion of an oversized central cavity together with circular and rectangular waveguide impedance transformers at the common port allows the achievement of a full-band operation with excellent electrical performance, while maintaining a very simple and compact configuration. Only two layers of metal are required for the physical implementation of this structure in platelet configuration. A prototype has been designed covering the full Ka-band (26.5–40 GHz), showing an excellent measured performance with around 30 dB of return loss, 0.18 dB of insertion loss, and less than 1.5° of phase imbalance.

scholarly journals Investigation on extreme frequency shift in silica fiber-based high-power Raman fiber laser

2018 ◽  
Vol 6 ◽  
Author(s):  
Jiaxin Song ◽  
Hanshuo Wu ◽  
Jun Ye ◽  
Hanwei Zhang ◽  
Jiangming Xu ◽  
...  
Keyword(s):  
Frequency Shift ◽  
Fiber Laser ◽  
High Power ◽  
High Efficiency ◽  
Maximum Output Power ◽  
Gain Medium ◽  
Maximum Output ◽  
Optical Efficiency ◽  
Central Wavelength ◽  
Raman Fiber Laser

In this paper, we experimentally investigated the extreme frequency shift in high-power Raman fiber laser (RFL). The RFL was developed by using a pair of fiber Bragg gratings with fixed and matched central wavelength (1120 nm) combined with a piece of 31-m-long polarization maintaining (PM) passive fiber adopted as Raman gain medium. The pump source was a homemade high-power, linearly polarized (LP) wavelength-tunable master oscillator power amplifier (MOPA) source with ${\sim}25~\text{nm}$ tunable working range (1055–1080 nm). High-power and high-efficiency RFL with extreme frequency shift between the pump and Stokes light was explored. It is found that frequency shift located within 10.6 THz and 15.2 THz can ensure efficient Raman lasing, where the conversion efficiency is more than 95% of the maximal value, 71.3%. In addition, a maximum output power of 147.1 W was obtained with an optical efficiency of 71.3%, which is the highest power ever reported in LP RFLs to the best of our knowledge.

scholarly journals Design and simulate a doherty power amplifier using GaAs technology for telecommunication applications

2019 ◽  
Vol 15 (2) ◽  
pp. 845
Author(s):  
Ehsan Barmala
Keyword(s):  
Output Power ◽  
Power Amplifier ◽  
Power Amplifiers ◽  
High Efficiency ◽  
Maximum Output Power ◽  
Input Power ◽  
Power Divider ◽  
Maximum Efficiency ◽  
Maximum Output ◽  
Doherty Power Amplifier

<span>In this paper, a Doherty power amplifier was designed and simulated at 2.4 GHz central frequency which has high efficiency. A Doherty power amplifier is a way to increase the efficiency in the power amplifiers. OMMIC ED02AH technology and PHEMT transistors, which is made of gallium arsenide, have been used in this simulation. The Doherty power amplifier unique feature is its simple structure which is consisting of two parallel power amplifiers and transmission lines. In order to integrate the circuit, the Doherty power transmission amplifier lines were implemented using an inductor and capacitive components. Also, the Wilkinson power divider is used on the chip input. To improve the efficiency, the auxiliary amplifier dimensions is selected enlarge and the further input power is allocated it by the power divider. A parallel R-C circuit has been used at the input of transistors to improve their stability. Simulation results show that the Doherty power amplifier has 17.2 dB output power gain, 23 dBm maximum output power, and its output power P<sub>1dB</sub> =22.6dBm at compression point -1 dB, also, its maximum efficiency is 55.5%.</span>

LD-pumped high-power continuous-wave Pr3+:YLF deep red lasers at 718.5 and 720.8 nm

Laser Physics ◽  
2021 ◽  
Vol 32 (2) ◽  
pp. 025801
Author(s):  
Xiangrui Liu ◽  
Zhuang Li ◽  
Chengkun Shi ◽  
Bo Xiao ◽  
Run Fang ◽  
...  
Keyword(s):  
Output Power ◽  
High Power ◽  
Slope Efficiency ◽  
Laser Emission ◽  
Continuous Wave ◽  
Optical Glass ◽  
Maximum Output Power ◽  
Glass Plate ◽  
Maximum Output ◽  
First Time

Abstract We demonstrated 22 W LD-pumped high-power continuous-wave (CW) deep red laser operations at 718.5 and 720.8 nm based on an a-cut Pr3+:YLF crystal. The output power of both polarized directions reached the watt-level without output power saturation. A single wavelength laser operated at 720.8 nm in the π-polarized direction was achieved, with a high output power of 4.5 W and high slope efficiency of approximately 41.5%. To the best of our knowledge, under LD-pumped conditions, the laser output power and slope efficiency are the highest at 721 nm. By using a compact optical glass plate as an intracavity etalon, we suppressed the π-polarized 720.8 nm laser emission. And σ-polarized single-wavelength laser emission at 718.5 nm was achieved, with a maximum output power of 1.45 W and a slope efficiency of approximately 17.8%. This is the first time that we have achieved the σ-polarized laser emission at 718.5 nm generated by Pr3+:YLF lasers.

scholarly journals Study on the Efficiency and Dynamic Characteristics of an Energy Harvester Based on Flexible Structure Galloping

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6548
Author(s):  
Peng Liao ◽  
Jiyang Fu ◽  
Wenyong Ma ◽  
Yuan Cai ◽  
Yuncheng He
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Physical Model ◽  
Energy Harvester ◽  
High Efficiency ◽  
Lateral Displacement ◽  
Maximum Output Power ◽  
Flexible Structure ◽  
Maximum Output ◽  
Cfd Numerical Simulation

According to the engineering phenomenon of the galloping of ice-coated transmission lines at certain wind speeds, this paper proposes a novel type of energy harvester based on the galloping of a flexible structure. It uses the tension generated by the galloping structure to cause periodic strain on the piezoelectric cantilever beam, which is highly efficient for converting wind energy into electricity. On this basis, a physical model of fluid–structure interaction is established, and the Reynolds-averaged Navier–Stokes equation and SST K -ω turbulent model based on ANSYS Fluent are used to carry out a two-dimensional steady computational fluid dynamics (CFD) numerical simulation. First, the CFD technology under different grid densities and time steps is verified. CFD numerical simulation technology is used to simulate the physical model of the energy harvester, and the effect of wind speed on the lateral displacement and aerodynamic force of the flexible structure is analyzed. In addition, this paper also carries out a parameterized study on the influence of the harvester’s behavior, through the wind tunnel test, focusing on the voltage and electric power output efficiency. The harvester has a maximum output power of 119.7 μW/mm3 at the optimal resistance value of 200 KΩ at a wind speed of 10 m/s. The research results provide certain guidance for the design of a high-efficiency harvester with a square aerodynamic shape and a flexible bluff body.

scholarly journals Development and Piezoelectric Properties of a Stack Units-Based Piezoelectric Device for Roadway Application

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7708
Author(s):  
Chenchen Li ◽  
Fan Yang ◽  
Pengfei Liu ◽  
Chaoliang Fu ◽  
Quan Liu ◽  
...  
Keyword(s):  
Stress Distribution ◽  
Piezoelectric Properties ◽  
Maximum Output Power ◽  
Negative Relationship ◽  
High Energy ◽  
Open Circuit ◽  
Load Test ◽  
Electrical Performance ◽  
Maximum Output ◽  
Piezoelectric Device

To improve the energy harvesting efficiency of the piezoelectric device, a stack units-based structure was developed and verified. Factors such as stress distribution, load resistance, loads, and loading times influencing the piezoelectric properties were investigated using theoretical analysis and experimental tests. The results show that the unit number has a negative relationship with the generated energy and the stress distribution has no influence on the power generation of the piezoelectric unit array. However, with a small stress difference, units in a parallel connection can obtain high energy conversion efficiency. Additionally, loaded with the matched impedance of 275.0 kΩ at 10.0 kN and 10.0 Hz, the proposed device reached a maximum output power of 84.3 mW, which is enough to supply the low-power sensors. Moreover, the indoor load test illustrates that the electrical performance of the piezoelectric device was positively correlated with the simulated loads when loaded with matched resistance. Furthermore, the electrical property remained stable after the fatigue test of 100,000 cyclic loads. Subsequently, the field study confirmed that the developed piezoelectric device had novel piezoelectric properties with an open-circuit voltage of 190 V under an actual tire load, and the traffic parameters can be extracted from the voltage waveform.

scholarly journals High-power long-wave infrared laser based on polarization beam coupling technique

2020 ◽  
Vol 8 ◽  
Author(s):  
Yingjie Shen ◽  
Chuanpeng Qian ◽  
Xiaoming Duan ◽  
Ruijun Lan
Keyword(s):  
Output Power ◽  
High Power ◽  
Beam Quality ◽  
Maximum Output Power ◽  
Infrared Laser ◽  
Maximum Output ◽  
Coupling Technique ◽  
Long Wave ◽  
Beam Coupling ◽  
Long Wave Infrared

We demonstrated a high-power long-wave infrared laser based on a polarization beam coupling technique. An average output power at $8.3~\unicode[STIX]{x03BC}\text{m}$ of 7.0 W was achieved at a maximum available pump power of 107.6 W, corresponding to an optical-to-optical conversion of 6.5%. The coupling efficiency of the polarization coupling system was calculated to be approximately 97.2%. With idler single resonance operation, a good beam quality factor of ${\sim}1.8$ combined with an output wavelength of $8.3~\unicode[STIX]{x03BC}\text{m}$ was obtained at the maximum output power.

C-Ku band 120% relative bandwidth high efficiency high power amplifier using GaN HEMT

2009 ◽  
Author(s):  
Eigo Kuwata ◽  
Koji Yamanaka ◽  
Tasuku Kirikoshi ◽  
Akira Inoue ◽  
Yoshihito Hirano
Keyword(s):  
Power Amplifier ◽  
High Power ◽  
High Efficiency ◽  
Gan Hemt ◽  
High Power Amplifier ◽  
Relative Bandwidth ◽  
Ku Band

scholarly journals A Compact and High Efficiency Intracavity Opo Based on Periodically-poled Lithium Niobate

2020 ◽  
Author(s):  
Ke Wang ◽  
Mingyao Gao ◽  
Shuhui Yu ◽  
Jian Ning ◽  
Zhenda Xie ◽  
...  
Keyword(s):  
Lithium Niobate ◽  
High Efficiency ◽  
Continuous Wave ◽  
Maximum Output Power ◽  
Maximum Output ◽  
Periodically Poled ◽  
Periodically Poled Lithium Niobate ◽  
Optical Parametric ◽  
Simulated Temperature ◽  
Output Laser

Abstract We demonstrate a compact, high-efficiency and widely tunable intracavity singly resonant optical parametric oscillator (IC-OPO) based on multichannel periodically-poled lithium niobate (PPLN). The IC-OPO is composed of 808 nm pump laser diode (LD), Nd:YVO4 laser and linear OPO. The continuous-wave (CW) mid-infrared (MIR) output laser is tunable from 2.25 μm to 4.79 μm. The maximum output power exceeds 1.08 W at 3.189 μm at 9.1 W LD pump power and the conversion efficiency is 11.88 %. We also build up a prototype with volume of Wmm3 and its total weight is less than 2 Kg. The measured power stability is 1.3 % Root Meat Square (RMS) for a 3 h duration under simulated high temperature conditions of 40 ℃. RMS is 2.6 % for a 4 h duration when simulated temperature is - 40 ℃.

scholarly journals High-Speed and High-Power 940 nm Flip-Chip VCSEL Array for LiDAR Application

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1237
Author(s):  
Kuo-Bin Hong ◽  
Wei-Ta Huang ◽  
Hsin-Chan Chung ◽  
Guan-Hao Chang ◽  
Dong Yang ◽  
...  
Keyword(s):  
High Power ◽  
High Speed ◽  
Flip Chip ◽  
Maximum Output Power ◽  
Thermal Characteristics ◽  
Cavity Surface ◽  
Maximum Output ◽  
Two Samples ◽  
Vertical Cavity Surface ◽  
Surface Emitting Laser

In this paper, we demonstrate the design and fabrication of a high-power, high-speed flip-chip vertical cavity surface emitting laser (VCSEL) for light detection and ranging (LiDAR) systems. The optoelectronic characteristics and modulation speeds of vertical and flip-chip VCSELs were investigated numerically and experimentally. The thermal transport properties of the two samples were also numerically investigated. The measured maximum output power, slope efficiency (SE) and power conversion efficiency (PCE) of a fabricated flip-chip VCSEL array operated at room-temperature were 6.2 W, 1.11 W/A and 46.1%, respectively. The measured L-I-V curves demonstrated that the flip-chip architecture offers better thermal characteristics than the conventional vertical structure, especially for high-temperature operation. The rise time of the flip-chip VCSEL array was 218.5 ps, and the architecture of the flip-chip VCSEL with tunnel junction was chosen to accommodate the application of long-range LiDAR. The calculated PCE of such a flip-chip VCSEL was further improved from 51% to 57.8%. The device design concept and forecasting laser characteristics are suitable for LiDAR systems.

scholarly journals Extended Bandwidth and Increased Efficiency Quasi-Doherty Power Amplifier Design With A Revised Approach For Load Modulation

2021 ◽  
Author(s):  
Seyedehmarzieh Rouhani ◽  
Kasra Rouhi ◽  
Adib Abrishamifar ◽  
Majid Tayarani
Keyword(s):  
Power Amplifier ◽  
High Power ◽  
Maximum Output Power ◽  
Input Power ◽  
Maximum Efficiency ◽  
Maximum Output ◽  
Power Added Efficiency ◽  
Active Feedback ◽  
Doherty Power Amplifier ◽  
Load Modulation

This paper presents an approach to power added efficiency (PAE) increase for Quasi-Doherty power amplifier (Q-DPA) design. For this aim, active feedback is utilized instead of a passive quarter wavelength transmission line (TL) usage, which is conventionally used in the DPA schematic. PAE increase can be done by applying an accurate load modulation to the main amplifier (PAmain), especially for technologies in which output impedance of the main power amplifier (Zout,main) considerably varies in both low and high power regions. Because such precise modulation is still based on a modified TL, this approach suffers from the inherent narrowband behavior of that TL. As a consequence, expecting a wideband DPA may not be satisfied in all cases. To deal with this issue, active feedback is used to play a role in reaching PAmain, which is not saturated before, to its maximum efficiency at the highest level of received input power (Pin) in the high power region. Following Zout,main trajectories in power and frequency sweeps simultaneously just by a passive TL are not needed anymore. Still, for the sake of preventing total PAE degradation due to the consummated power by the feedback path’s power amplifier (PAfeedback) should be limited, analytical confinement is provided in this work. A comparison is made between GaAs pHEMT 0.25um MMIC technology-based conventional DPA and the proposed revised approach based-DPA to verify the mentioned approach. The proposed PA shows maximum output power of 33.4 dBm, maximum PAE of 41.6, fractional bandwidth of 11%. The Q-DPA works with a maximum power gain of 24.16.

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