Comparison of carbon velvet and polymer velvet cathodes

This paper presents the results of an experimental comparison of carbon velvet cathodes and a common polymer velvet cathode. The comparative results show that the initiation of the carbon velvet cathodes is slightly slower, and it is possible that the output microwave power of the carbon velvet cathodes is higher than that of the common polymer velvet cathode under the same diode voltage. However, the output microwave power and pulse width of the carbon velvet cathodes reduce obviously when part of the fibers fall from the cathode. The tips of the polymer velvet fibers are expanded and bent because of the erosion in operation, which shortens the lifetime of the polymer velvet cathode. While, this does not happen to the tips of the carbon velvet fibers, which shows that the lifetime of the