Broadband digital direct down conversion receiver suitable for software defined radio

While a significant amount of work has been carried out on digital receivers to support flexible and adaptive high data rate processing for multiple systems, small interest has been shown on the RF part and especially the advantages of using a broadband RF front end. This paper presents a challenge raised in the design of a single flexible multimode and multiband RF receiver. It proposes a new direct down conversion technique and its advantages using six-port techniques. A study of six-port based direct down conversion receiver is first presented. Then the functionality of this direct conversion receiver concept is then verified for a multi-carrier system based on HIPERLAN/2 parameters and a single-carrier system based on UMTS-FDD parameters. This new direct down conversion receiver technique is suitable for multi-system platforms and software defined radios.