Simultaneous transmission of non-contiguous frequency bands for mobile radio using a pulse-width-modulated switch-mode stage

This paper demonstrates the capability of supporting simultaneous transmission of non-contiguous frequency bands using pulse width modulation (PWM) and a single switch-mode stage for two signals, one at 800 MHz and the other at 1800 MHz (1 GHz spacing), each meeting the 3GPP ACLR requirements. Moreover, we present a PWM current-mode class-S power amplifier designed for a carrier frequency of 2600 MHz. The complete class-S amplifier is characterized using a clipped single-carrier WCDMA signal at 2600 MHz. The measured spectrum at the amplifier output meets the 3GPP ACLR requirements within a 10 dB output power range. With an almost identical setup, we are able to support carrier frequencies from 800 MHz up to 2.6 GHz, confirming the frequency flexibility of the PWM switch-mode stage.