A passive frequency tripler using the new small-size bandpass filter with low insertion loss

In this paper, a passive frequency tripler using APDP (anti-parallel diode pair) in which a new structure of bandpass filter (BPF) with low insertion loss and small size is presented. The tripler using the new small-size BPF is measured and compared with one using a conventional coupled line BPF. This BPF shows the insertion loss of less than 0.7 dB within the bandwidth of 16.41~19.23 GHz. The conversion loss of the tripler is about 16.6 ~18.5 dB with flatness of less than plusmn1 dB at the fundamental frequency of 5.72 ~ 6.28 GHz. The suppression characteristics for the 1^st and 5^th harmonic signals at 6.1 GHz are -32.16 dBc and -44.6 dBc, respectively, and its phase noise attenuation is about 9.5 dB at 100 kHz offset.