Software Defined Radio를 위한 I/Q 부정합 보정 기능을 갖는 이중 대역 Six-Port 직접변환 수신기

Abstract

In this paper, a new six-port direct conversion receiver for high-speed multi-band multi-mode wireless communication system such as software defined radio(SDR) is proposed. The designed receiver is composed of two CMOS four-port BPSK receivers and a dual-band one-stage polyphase filter for quadrature LO signal generation. The four-port BPSK receiver, implemented in 0.18 CMOS technology for the first time in microwave-band, is composed of two active combiners, an active balun, two power detector, and an analog decoder. The proposed polyphase filter adopt type-I architecture, one-stage for reduction of the local oscillator power loss, and LC resonance structure instead of using capacitor for dual-band operation. In order to extent the operation RF bandwidth of the proposed six-port receiver, we include I/Q phase and amplitude calibration scheme in the six-port junction and the power detector. The calibration range of the phase and amplitude mismatch in the proposed calibration scheme is 8 degree and 14 dB, respectively. The validity of the designed six-port receiver is successfully demonstrated by modulating M-QAM, and M-PSK signal with 40 Msps in the two-band of 900 MHz and 2.4 GHz.