Abstract: In order to improve the wave and wind detection capability of the portable high frequency surface wave radar (HFSWR) OSMAR-S, a smallaperture array based on the cross-loop/monopole antenna system was considered. This paper analyzes the effect of array element spacing on the beamforming of this array, and studies the effect of lowsidelobe processing on the grating lobe. Simulations show that the gain of the grating lobe is weaker than that of the mainlobe and the grating lobe can be suppressed completely by lowsidelobe processing. Then, beampointing performances of this array with different array element spacings are compared, which indicates that we can appropriately increase the array element spacing, breaking through the strict constraint that the array element spacing can not be more than half the radar wavelength, and get more narrow mainlobe in the　case of the obtaining the same uniform sidelobe.