This research proposes a through-wall S-band ultra-wideband (UWB) switched-antenna-array radar scheme for detection of stationary human subjects from respiration. The Tx and Rx antennas are of Vivaldi type with high antenna gain (10 dBi) and narrow-angle directivity. The S-band frequency (2-4 GHz) is capable of penetrating non-metal solid objects and detecting human respiration behind the solid wall. Under the proposed radar scheme, the reflected signals are algorithmically preprocessed and filtered to remove unwanted signals, and 3D signal array is converted into 2D array using statistical variance. The images are reconstructed using back-projection algorithm prior to Sinc-filtered refinement. To validate the detection performance of the through-wall UWB radar scheme, simulations are carried out and experiments performed with single and multiple real stationary human subjects and a mannequin behind the concrete wall. The UWB switched-antenna-array radar is capable of distinguish between the human subjects and the mannequin. The novelty of this research lies in the use of UWB with switched-antenna-array radar to efficiently detect stationary human subjects behind the solid wall.