Frequency- and amplitude-tunable X-to-Ku band SiGe ring oscillators for multiband BIST applications

An 8-17 GHz SiGe ring oscillator covering the X- and Ku-bands for built-in-self-test of multiband system-on-chip solutions is demonstrated. The oscillator features highly linear frequency control over the bandwidth, with 72% tuning range in a small form factor of 0.652 mm
²
. To the author's knowledge, this is the widest tuning range/smallest form factor combination achieved by a ring oscillator that spans both X and Ku bands. A second ring oscillator with band selectivity and output power control is also presented, covering the 9-11 GHz and 17-21 GHz bands. This second oscillator features an ultra-small form factor of only 0.036 mm
²
. Both oscillator designs are based on a 3.3 V supply and were implemented in a commercially-available 180 nm SiGe BiCMOS platform.