Multiferroic materials-based nonlinear transmission lines for high power microwaves generation
| Autor: | CHIA-LUN CHAO, 趙家倫 |
|---|---|
| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 107 High power microwaves (HPMs) are electromagnetic waves with the power level higher than 1 MW operated at the frequency above 0.3 GHz. They are often used in military applications and communication systems. Conventional HPM sources require vacuum equipment and strong magnetic fields for converting the kinetic energy of the electron beams into electromagnetic wave energy which are heavy and complicated. Another approach of generating HPMs is utilizing nonlinear transmission lines (NLTLs). Due to the characteristics of dispersions and non-linearity, the input high-voltage and high-current DC pulses are converted into solitary output waves with high power, and RF frequencies. Although they have compact sizes and simple systems, the output frequency and power levels of NLTLs can be affected by the eddy current loss, hysteresis, and dielectric relaxations. Hence, it is difficult to obtain GHz microwave output or they may consume lots of energy. In this research, we proposed a new type of NLTLs by exploiting a multiferroic-material based voltage-controlled inductors for generating HPMs. The main advantage was to reduce the need of high input currents and dielectric materials leading to high output microwave frequencies and high output power levels. The thesis included three parts. First, a tunable NLTL was proposed where the operating frequency of the output signal could be controlled by the external voltage. Next, a different NLTL was developed to generate chirp signals for radar applications. Last, a voltage-controlled NLTL composed of pure multiferroic nonlinear inductors was invented for generating HPMs with GHz frequency range and MW power level. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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