Six-Port Direct Conversion Receiver: Novel Calibration for Multi-Port Nonlinear Circuits

Atsushi HONDA  Kei SAKAGUCHI  Jun-ichi TAKADA  Kiyomichi ARAKI  

IEICE TRANSACTIONS on Electronics   Vol.E87-C   No.9   pp.1532-1539
Publication Date: 2004/09/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Wave Technologies for Wireless and Optical Communications)
Category: Components and Devices
software defined radio,  six-port direct conversion receiver,  nonlinearity calibration,  

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An RF front-end using a six-port circuit is a promising technology for realization of a compact software defined radio (SDR) receiver. Such a receiver, called a six-port direct conversion receiver (DCR), consists of analog circuit and digital signal processing components. The six-port DCR itself outputs four different linear combinations of received and local signals. The output powers are measured at each port, and the received signal is recovered by solving a set of linear equations. This receiver can easily cover a wide frequency band unlike the conventional DCR since it does not require the precise orthogonality that the conventional one does. In this paper, we propose a novel calibration method for a six-port system that includes nonlinear circuits such as diode detectors. We demonstrated the demodulation performance of a six-port DCR by computer simulation and experiments at 1.9, 2.45, and 5.85 GHz.