A 1.8-V operation 5-GHz-band CMOS frequency doubler using current-reuse circuit design technique

This paper describes the circuit design and measurement results of a new CMOS frequency doubler proposed for 5-GHz-band wireless applications. The doubler, which can operate at 1.8 V, was fabricated in a standard 0.18-μm bulk CMOS technology which has no extra processing steps to enhance RF performance. A current-reuse circuit-design technique is successfully incorporated into the doubler so as to realize both on-chip input/output matching and adequate conversion gain with low input power drive despite the utilization of the standard bulk CMOS technology. The doubler with a single input/output interface features a bypass resistor placed between common ground and a source node of the second stage FET in the current-reuse topology, thereby improving both input power level and conversion gain while saving waste current. Measurement results under the condition of 5.2 GHz and 1.8 V reveal the following good performance: a 2.7-dB maximum conversion gain, a 0.3-dBm high output power, and a 9-mA low current dissipation are achieved with a 2.6-GHz, -3-dBm input power. With a 7-mA low current dissipation and a -7-dBm low input power, the doubler can deliver conversion gain as high as 0 dB. These measurement results are good agreement with the simulated ones.