RF Performance Improvement of InP Frequency Divider by Using Enhanced f T -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.