Abstract: A multi-band power amplifier in a wireless communication system includes: a plurality of matching circuits connected in parallel to an output stage of the power amplifier and corresponding to a plurality of different operation frequencies, respectively; and a plurality of high-frequency amplifiers connected to the plurality of matching circuits, respectively. The plurality of high-frequency amplifiers are selectively operated depending on the operation frequencies. Each of the high-frequency amplifiers may include a plurality of stages. Each of the matching circuits may include a high-frequency transformer.

Abstract: A heterodyne receiver of a wireless communication system using an analog discrete-time signal processing is provided. The heterodyne receiver includes: a radio signal processing unit configured to extract a signal of a desired band from a received radio signal and convert the extracted signal into an intermediate frequency (IF) signal that is an integer multiple of a sample rate specified in a specification of the wireless communication system; a discrete-time signal processing unit configured to charge-sample the IF signal in unit of a predetermined time and perform an anti-aliasing filtering and a successive decimation on the charge-sampled signal, a final output rate according to the decimation being an integer multiple of the specified sample rate; and an analog-to-digital conversion unit configured to convert the successively-decimated analog signal into a digital signal.