Abstract: A 10-fold frequency multiplier with Low phase noise has been designed and manufactured．It is the 5-fold multiplieris combined with the 2-fold multiplier，the outputpower is more than 10dBm at 1GHz when the input power is about 0dBm at 100MHz, the suppression of spurs is less than -55dB. The designideas，tuningmethods and measured results of this multiplier are presented in this paper.

Key words: Phase noise, Frequency multiplier, Filter