Architectural Evolution of Integrated M-Phase High-Q Bandpass Filters

Abstract

-phase bandpass filters (BPFs) are analyzed, and variations of the structure are proposed. For values of that are integer multiples of 4, the conventional -phase BPF structure is modified to take complex baseband impedances and frequency-translate their complex impedance response to the local oscillator frequency. Also, it is demonstrated how the -phase BPF can be modified to implement a high quality factor (Q) image-rejection BPF with quadrature RF inputs. In addition, we present high-Q BPFs whose center frequencies are equal to the sum or difference of the RF and IF (intermediate frequency) clocks. Such filters can be useful in heterodyne receiver architectures.