Far-field Wireless Power Transfer (WPT) has emerged as a potential power source for the Internet of Things (IoT) and Wireless Sensor Network (WSN). The expansion of the power transfer range is one of the key challenges to make the technology viable. In this letter, we experimentally study a channel-adaptive joint beamforming and waveform architecture to expand the power transfer range. WPT experiments have been conducted in a variety of wireless channels at various distances in a realistic indoor environment. The measurement data have been fitted using a simple analytical model to analyze the output DC power and achievable range improvement depending on the signal design schemes and the number of tones and antennas. The model shows a clear relationship between signal design versus output DC power and achievable range, and highlight the significant benefit of the proposed architecture to expand the power transfer range.