Abstract

A fully integrated GaAs HBT dual frequency VCO providing a high frequency 18 GHz signal but also a half-frequency 9 GHz signal to a PLL is described. The key advance is achieving good phase noise performance, over a wide frequency band, with very good temperature behaviour and harmonics suppression, at a low cost and small size. More than 3 GHz tuning range is achieved at the 18 GHz port, with 25 dB suppression of fundamental frequency (9 GHz).The 18 GHz VCO yields 5 dBm output power, while on the 9 GHz port it shows more than –10 dBm output power. The chip was assembled in a test jig, then a phase noise of –95 dBc/Hz @ 100 kHz offset was obtained at 9 GHz.