Abstract: To fully realize the potential of guided-wave electromagnetic acoustic transducer (EMAT) technology in non-contact measurement and large-area scanning, critical advances are required in transducer efficiency and the development of efficient, portable measurement systems. This work is based on a narrow-magnet EMAT and a frequency/wavelength calibration method, whereby the conversion efficiency of the narrow-magnet EMAT was synergistically enhanced by optimizing the magnet-to-coil width ratio in combination with a magnetic yoke scheme. Building on this, a matched embedded measurement circuit was developed, achieving co-design at both the sensor and system levels. The integrated system consumes 2.4 W of power and achieves a positioning error of less than 1 mm for defects on an 800 mm × 800 mm × 1 mm aluminum plate, while also showing significant suppression of artifacts. These results provide an effective reference for the design and application of portable EMAT guided-wave testing systems under power constraints.