Abstract
This paper presents an ultra-wideband digital attenuator using hybrid topology and capacitive phase compensation method, which achieves high amplitude control precision and low phase shifts from DC to 54 GHz in 0.18-μm SiGe BiCMOS technology. The parasitic effect of the switch transistor and capacitive phase compensation for high-band response improvement are visualized and analyzed. A maximum attenuation of 15.5 dB is achieved with a step of 0.5 dB. Simulated results show the insertion loss (IL) of the attenuator is 4.25-9.35 dB and the RMS amplitude/phase errors are less than 0.35 dB/2.9° over the operating frequency. While the return losses of all 32 states are better than 10 dB with a compact core area of 0.046 mm 2 .