Compact Transformer-Based Distributed Amplifier for UWB Systems

This brief presents a new compact structure of distributed amplifiers (DAs) employing integrated transformers to lower the impedance values of input and output transmission lines. This impedance conversion allows us to employ smaller inductors for input and output transmission lines than those used in conventional DAs, resulting in a considerable saving of chip area. A fabricated five-stage DA in 0.18-μm complementary metal-oxide-semiconductor technology presents an average gain of 12 dB over a bandwidth of 3.4-11 GHz. The measured input return loss is less than 9.2 dB, and the output return loss is less than 9.5 dB over the entire bandwidth. With a chip area of 0.76 mm × 0.4 mm, the amplifier consumes 38 mW from a 1.8-V direct-current power supply.