Ultra high speed direct digital synthesizer using InP DHBT technology

Direct Digital Synthesizers (DDS) offer advantages such as precise beam shaping and forming over conventional RF approaches. This paper discusses novel design and process techniques that enable direct digital synthesis of S-band output frequencies using our current InP double-heterojunction bipolar transistor (DHBT) technology with a cantilevered base layer and undercut collector. The test results demonstrate a DDS chip operating at the world record clock rate of 9.2 GHz. Further design and process improvements will be implemented in future generation circuits that will enable synthesis of Ku-band frequencies.