Research on broad-band high-gain klystrons of megawatt output power level

Author(s):  
Nu Delu
2019 ◽  
Vol 11 (7) ◽  
pp. 546-553 ◽  
Author(s):  
Marcin Góralczyk ◽  
Wojciech Wojtasiak

AbstractThis paper describes the development of a power amplifier operating over a 2.4–2.5 GHz frequency range with the output power level more than 15 W and 60% PAE. The transistor applied was the 10 W (13 W Psat) power GaN HEMT (CGH40010F from Wolfspeed) recommended up to 6 GHz. A harmonic tuning method was used to achieve even 30% more output power than the CGH40010 transistor was specified to deliver while maintaining high gain and high efficiency. Furthermore, an accuracy analysis of amplifier design was also conducted. It included validation and correction of the available transistor models as well as validation of the models of microstrip circuits implemented in ADS. Finally, it was concluded that both the mentioned sources of errors contributed at a similar level.


Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1214
Author(s):  
Thanh Dat Nguyen ◽  
Jong-Phil Hong

This paper presents a push-push coupled stack oscillator that achieves a high output power level at terahertz (THz) wave frequency. The proposed stack oscillator core adopts a frequency selective negative resistance topology to improve negative transconductance at the fundamental frequency and a transformer connected between gate and drain terminals of cross pair transistors to minimize the power loss at the second harmonic frequency. Next, the phases and the oscillation frequencies between the oscillator cores are locked by employing an inductor of frequency selective negative resistance topology. The proposed topology was implemented in a 65-nm bulk CMOS technology. The highest measured output power is −0.8 dBm at 353.2 GHz while dissipating 205 mW from a 2.8 V supply voltage.


2021 ◽  
Author(s):  
R. A. Perez-Herrera ◽  
P. Roldan-Varona ◽  
M. Galarza ◽  
S. Sañudo-Lasagabaster ◽  
L. Rodriguez-Cobo ◽  
...  

Abstract A hybrid Raman-erbium random fiber laser (RFL) with a half-open cavity assisted by chirped artificially controlled backscattering fiber reflectors (ACBFRs) is presented. A combination of 2.4 km of dispersion compensating fiber (DCF) with two highly erbium-doped fiber (EDF) pieces of 5 m length was used as gain medium. A single random laser emission line centered at 1553.8 nm with an output power level of -6.5 dBm and an optical signal to noise ratio (OSNR) of 47 dB was obtained when pumped at 37.5 dBm. A full width at half maximum (FHWM) of 1 nm and a 100% confidence level (CL) output power instability as low as 0.08 dB were measured. The utilization of the new laser cavity as a temperature and strain sensor is also experimentally studied.


Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 929 ◽  
Author(s):  
Koen Bastiaens ◽  
Dave C. J. Krop ◽  
Sultan Jumayev ◽  
Elena A. Lomonova

This paper concerns the optimal design and comparative analysis of resonant and non-resonant high-frequency GaN-based rotating transformers. A multi-physical design approach is employed, in which magnetic, electrical, and thermal models are coupled. The results are verified by experiments. Two different optimization objectives are considered; firstly, the efficiency of two standard core geometries is maximized for a required output power level. Secondly, a geometrical optimization is performed, such that the core inertia is minimized for the desired output power level. The results of both design optimizations have shown large improvements in terms of output power and core inertia as a result of applying series–series resonant compensation.


2016 ◽  
Vol 8 (4-5) ◽  
pp. 691-702 ◽  
Author(s):  
Rocco Giofré ◽  
Paolo Colantonio ◽  
Elisa Cipriani ◽  
Franco Giannini ◽  
Laura Gonzalez ◽  
...  

This paper describes the development of an L-Band (f0= 1.575 GHz) high power and efficient solid state power amplifier (SSPA) designed for the European satellite navigation system (i.e. Galileo). The amplifier, developed in the framework of the European Project named SLOGAN, exploits the GH50-10 GaN technology available at United Monolithic Semiconductor foundry. The aim of the project is to offer, using as much as possible European technologies, a valid alternative to replace traveling wave tube amplifiers with more compact and reliable systems. All the SSPA functionalities, i.e. power supply, power conditioning and radio frequency amplification, are integrated in the developed architecture and accommodated in a single box with limited volume and mass. The required output power level is achieved by parallelizing several GaN die power bars of 12 and/or 25.6 mm. In continuous wave operating mode, the overall SSPA delivers an output power higher than 250 W at less than 2 dB of gain compression in the whole E1-band. Moreover, the registered gain and efficiency are higher than 67 dB and 54%, respectively.


Author(s):  
M. F. Karushkin

This is the second part of the two-part article, which summarizes the state-of-the-art results in the development of synchronized oscillators based on IMPATT (IMPact ionization Avalanche Transit-Time) diodes. The first part of the paper presented the electrodynamic design of oscillators, which contain a resonant oscillatory system with silicon IMPATT diodes and are synchronized by an external source of microwave oscillations. The second part of the paper considers the methods for stabilizing the parameters of IMPATT oscillators, which make it possible to create coherent power sources in the millimeter wavelength range. The specifics of pulse generators lies in the change in frequency within the microwave pulse relative to the change in temperature, which leads to a change in the impedance of the diode and thus to a phase change with respect to the synchronizing signal. Phase modulation is reduced or completely eliminated (which is necessary to ensure the coherence of the microwave transmitter) by using current compensation, i.e., by using the control current pulse with a special shape. The study demonstrates the expediency of introducing additional heating of the semiconductor structure of the IMPATT diode, which allows the initial temperature of the IMPATT diode in the region of the leading edge of each pulse to remain virtually constant and independent of the ambient temperature. Using these methods on silicon double-drift IMPATT diodes allowed creating synchronized oscillators with high frequency stability and an output power level from 20 to 150 W, which have a high degree of coherence in the synchronization mode with an external signal. The paper also presents the designs and parameters of coherent microwave power sources in the short-wave part of the millimeter wavelength range using the nonlinear properties of the IMPATT diodes in the radio-pulse conversion mode. This mode makes it possible to provide the output power level of the signal at the n-th harmonic Pout ≈1/n, which significantly exceeds the achieved characteristics of the frequency multipliers with charge accumulation, where Pout ≈ 1/n2. The output power of such devices is achieved at the level of 50–20 mW in the 75–180 GHz frequency range with a frequency multiplication factor of 1–15.


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