  We present the first beam test results with centimeter-scale AC-LGAD strip
sensors, using the Fermilab Test Beam Facility and sensors manufactured by the
Brookhaven National Laboratory. Sensors of this type are envisioned for
applications that require large-area precision 4D tracking coverage with
economical channel counts, including timing layers for the Electron Ion
Collider (EIC), and space-based particle experiments. A survey of sensor
designs is presented, with the aim of optimizing the electrode geometry for
spatial resolution and timing performance. Several design considerations are
discussed towards maintaining desirable signal characteristics with
increasingly larger electrodes. The resolutions obtained with several
prototypes are presented, reaching simultaneous 18 micron and 32 ps resolutions
from strips of 1 cm length and 500 micron pitch. With only slight
modifications, these sensors would be ideal candidates for a 4D timing layer at
the EIC.
