A Fully-Integrated 2.4 GHz Mismatch-Controllable RF Front-end Test Platform in 0.18µm CMOS

The design and implementation of a prototype testbench for a direct conversion receiver RF front-end targeted for the 2.4 GHz ISM band are described. The developed front-end provides user control of I/Q mismatch and is intended as a test vehicle for evaluation of various I/Q mismatch compensation methods implemented in the back-end. The I and Q path mixers can operate in normal mode, or they can be controlled externally to introduce a known mismatch, or controlled to compensate for the actual mismatch, which results in a dramatic increase in the image rejection ratio (IRR). A prototype of the proposed circuit was fabricated using TSMC 0.18 mum CMOS technology and includes a low noise amplifier (LNA), two mixers (with quadrature down-conversion) and a quadrature voltage-controlled oscillator (QVCO). It achieves a conversion gain of 40 dB, and a noise figure of 9.8 dB. The circuit dissipates 25 mW and occupies an active area of 2.5 mm².