scholarly journals Frequency Tuning Characteristics of a High-Power Sub-THz Gyrotron with Quasi-Optical Cavity

Electronics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 526
Author(s):  
Xiaotong Guan ◽  
Jiayi Zhang ◽  
Wenjie Fu ◽  
Dun Lu ◽  
Tongbin Yang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Power ◽  
Frequency Tuning ◽  
Optical Cavity ◽  
Separation Distance ◽  
Center Frequency ◽  
Broad Bandwidth ◽  
Particle In Cell ◽  
Power Frequency ◽  
Frequency Tunable

Motivated by some emerging high-frequency applications, a high-power frequency-tunable sub-THz quasi-optical gyrotron cavity based on a confocal waveguide is designed in this paper. The frequency tuning characteristics of different approaches, including magnetic field tuning, mirror separation adjustment, and hybrid tuning, have been investigated by particle-in-cell (PIC) simulation. Results predict that it is possible to realize a smooth continuous frequency tuning band with an extraordinarily broad bandwidth of 41.55 GHz, corresponding to a relative bandwidth of 18.7% to the center frequency of 0.22 THz. The frequency tunability is provided by varying the separation distance between two mirrors and correspondingly adjusting the external magnetic field. During the frequency tuning, the output power remains higher than 20 kW, which corresponds to an interaction efficiency of 10%. Providing great advantages in terms of broad bandwidth, smooth tuning, and high power, this research may be conducive to the development of high-power frequency-tunable THz gyrotron oscillators.

Frequency Tuning of a Nonlinear Electromagnetic Energy Harvester

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Longhan Xie ◽  
Ruxu Du
Keyword(s):  
Magnetic Field ◽  
Permanent Magnets ◽  
Energy Harvester ◽  
Frequency Tuning ◽  
Nonlinear Behavior ◽  
Stretch Ratio ◽  
Electromagnetic Energy ◽  
Elastic Strings ◽  
Simulation And Experiment ◽  
Frequency Tunable

This paper investigates a frequency-tunable nonlinear electromagnetic energy harvester. The electromagnetic harvester mainly consists of permanent magnets supported on the base to provide a magnetic field, and electrical coils suspended by four even-distributed elastic strings to be an oscillating object. When the base provides external excitation, the electrical coils oscillate in the magnetic field to produce electricity. The stretch length of the elastic strings can be tuned to change their stretch ratio by tuning adjustable screws, which can result in a shift of natural frequency of the harvester system. The transverse force of the elastic strings has nonlinear behavior, which broadens the system's frequency response to improve the performance of the energy harvester. Both simulation and experiment show that the above-discussed electromagnetic energy harvester has nonlinear behavior and frequency-tunable ability, which can be used to improve the effectiveness of energy harvesting.

Effect of different magnets and iron-platelets on the low frequency performance of membrane sound absorber

2021 ◽  
Vol 263 (6) ◽  
pp. 342-347
Author(s):  
Junjuan Zhao ◽  
Liying Zhu ◽  
Xinyun Li ◽  
Yueyue Wang ◽  
Wenjiang Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Sound Absorption ◽  
Tuning Range ◽  
Frequency Tuning ◽  
Low Frequency ◽  
Cavity Depth ◽  
Sound Absorber ◽  
Frequency Tunable ◽  
Compact Design ◽  
Frequency Properties

To achieve a compact design for low frequency tunable sound absorption, a membrane sound absorber (MSA) with nonlinear magnetic field is proposed in this paper. By employing a central iron platelet on the membrane, the MSA can be easily tuned by introducing a magnet at a distance from the platelet that can be adjusted. To investigate the low frequency properties of MSA with different magnets and iron-platelets, a series of impedance tube experiments are conducted in detail. The sample absorber has a rear cavity depth of 30 mm, three different magnets were used inside, tested results real that using a strong magnetic field can help broaden the frequency tuning range. Then, results from the MSA with five different sizes of iron plates tuned by one magnet show that the low-frequency tuning range moves to lower with the increase of the area of iron plates.

scholarly journals A High Power, Frequency Tunable Colloidal Quantum Dot (CdSe/ZnS) Laser

Nanomaterials ◽  
2017 ◽  
Vol 7 (2) ◽  
pp. 29 ◽  
Author(s):  
Saradh Prasad ◽  
Hanan AlHesseny ◽  
Mohamad AlSalhi ◽  
Durairaj Devaraj ◽  
Vadivel Masilamai
Keyword(s):  
Quantum Dot ◽  
High Power ◽  
Power Frequency ◽  
Colloidal Quantum Dot ◽  
Frequency Tunable
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