  The Low-Gain Avalanche Diode (LGAD) is a new silicon detector and holds wide
application prospects in particle physics experiments due to its excellent
timing resolution.
  The LGAD with a pixel size of 1.3 mm $\times$ 1.3 mm was used to construct a
High Granularity Timing Detector (HGTD) in ATLAS experiments to solve the
pile-up problem.
  Meanwhile, the Circular Electron Positron Collider (CEPC) also proposes
detectors using the LGAD. However, pixel LGAD exhibits higher readout
electronics density and cost, which somewhat limits the application of LGADs.
To decrease the readout electronics density, the Institute of High Energy
Physics (IHEP) of the Chinese Academy of Sciences has designed strip LGADs with
larger areas. These strip LGADs are all 19 mm in length but with different
widths of 1.0 mm, 0.5 mm, and 0.3 mm.
  This article provides a detailed introduction to the design parameters of
these strip LGADs and tests their electrical characteristics, including leakage
current, break-down voltage, depletion capacitance, etc.
  The timing resolution and signal-to-noise ratio of the three strip LGAD
sensors were investigated using a beta source test system.
  The position resolution parallel to the strip direction was tested and
analyzed for the first time using a pico-second laser test system.
  Tests have demonstrated that the timing resolution of strip LGADs can reach
about 37.5 ps, and position resolution parallel to the strip direction is
better than 1 mm.
