RF Performance Improvement of InP Frequency Divider by Using Enhanced fT-Doubler Technique

This letter presents a wideband high-speed static 1/2 frequency divider using a 0.8- {\mu }\text{m} indium phosphide (InP) process. In this design, some performance-enhanced unity-gain frequency ( {f_{T}} ) doubler structures are proposed and compared. Moreover, the application of an enhanced {f_{T}} -doubler technique, for the first time, improves the radio-frequency (RF) performance of the emitter-coupled logic (ECL) divider. The divider has better than 0.4- {f_{T}} frequency ranges from 0.2 to >66 GHz (single-ended sine wave input) within 165-GHz transistor {f_{T}} . The input-referred self-oscillation frequency (SOF) of the divider is 53.9 GHz, and the single-ended signal output power is from −5 to 2 dBm. The measured results confirm a great improvement in the performance of the ECL divider by using the enhanced {f_{T}} -doubler structure.