A 5–GHz band I/Q clock generator using a self–calibration technique

This paper presents a self-calibrated I/Q clock generation technique for a direct conversion receiver. A 5GHz RF transceiver chip with on-chip self-calibrated I/Q clock generation circuit is implemented in a 0.18-µm CMOS technology. A tunable poly-phase filter controlled by a delay-locked loop adjusts the delay of I/Q clock signal paths to generate the precise I/Q clock signals. Measurement shows that the proposed self-calibration technique achieves I/Q clock mismatch less than 2 degrees over process and temperature variations at 5 GHz frequency.