In the sixth-generation (6G), with the further expansion of array element number and frequency bands, the wireless communications are expected to operate in the near-field region. The near-field radio communications (NFRC) will become crucial in 6G communication systems. The new mid-band (6-24 GHz) is the 6G potential candidate spectrum. In this paper, we will investigate the channel measurements and characteristics for the emerging NFRC. First, the near-field spherical-wave signal model is derived in detail, and the stationary interval (SI) division method is discussed based on the channel statistical properties. Then, the influence of line-of-sight (LOS) and obstructed-LOS (OLOS) environments on the near-field effects and spatial non-stationary (SnS) characteristic are explored based on the near-field channel measurements at 11-15 GHz band. We hope that this work will give some reference to the NFRC research.