Polar Quantizer for Wireless Receivers: Theory, Analysis, and CMOS Implementation

Abstract

This paper presents the theory and analysis of IF polar receiver (PRX) architecture. By using new quantization techniques in the polar domain, the proposed receiver can boost the signal to quantization noise ratio (SQNR) compared to a traditional rectangular (I/Q) receiver. The proposed PRX is composed of a magnitude and a phase quantizer. The magnitude quantizer is similar to the conventional rectangular quantizer in voltage domain. The phase quantizer employs a time-to-digital converter (TDC) for phase detection. Furthermore, an intuitive graphical method is used to analyze the quantization properties of the polar quantization. A 10 bit polar quantizer is designed and fabricated in 130 nm CMOS, and achieves 2- to 5-dB of SQNR improvement compared to rectangular quantizer for signal bandwidths as high as 20 MHz.