KU-band image rejection sliding-IF transmitter in 0.13-uM CMOS process

摘要

The effects of gain/phase mismatch, and phase noise in a multiband double-image-rejection transmitter are investigated. Although a direct-I/Q modulator architecture is simple, the I/Q gain and phase mismatches directly affect the image rejection ratio (IRR) over the operating frequencies. However, the double-image-rejection transmitter (DIRT) has low sensitivity to a small I/Q phase mismatch while the IRR is predominantly dependent on the IF gain mismatch. Furthermore, there is a region of insensitivity to both gain and phase mismatches in the DIRT. For characterizing the effects of the I/Q mismatch and phase noise in the DIRT, the IRR, EVM, and SER are theoretically analyzed and simulated at the system level. The proposed DIRT with sliding-IF is implemented on a 0.13-um CMOS process to prove the insensitivity to the I/Q mismatch effects over the 11 GHz to 15 GHz multiband frequency ranges. For supporting the multiband functionality, frequency dividers-by-4/8/16 are utilized to generate 0.675 GHz, 1.35 GHz, and 2.7 GHz quadrature IF LO signals using a 10.8 GHz RF LO signal. The measurement results show that the in-band image rejection and LO leakage suppression are greater than 48.8 dBc and 43.5 dBc, respectively, over the wideband frequency range. The output-referred 1-dB compression point is obtained as high as -4 dBm with a 1.5 V power supply. A multiband DIRT operating above 10 GHz has not been previously reported.