Reconfigurable up-converter with image rejection

This paper presents a reconfigurable up-converter with image rejection. It consists of an FET mixer, a VCO, a lowpass filter and a tunable bandpass filter. It can shift a given input IF signal to any desired RF frequency within a wide frequency range while maintaining high image rejection level. With the change of VCO output frequency, the image, LO and harmonic frequencies also shift and maybe overlap. A novel tunable bandpass filter with harmonic suppression is adopted to suppress them, regardless of the frequency change. The implemented mixer has achieved more than 34 dB image rejection ratio within all the operation bands. This up-converter is cost-effective and simple in structure, suitable for multi-band discrete circuit application.