Polarization observations of solar microwave spike emission at high temporal and spectral resolutions

11 microwave spike events were observed with the 2.6-3.8 GHz solar radio sp ectrometer of Beijing Astronomical Observatory. The spikes have short durat ions (tens of ms) and weak flux densities (< 500 sfu), similar to the previ ous reports. Their degrees of polarization span over a large range, some sp ikes have frequency drifts as high as several GHz/s, Time delays of 8 ms or more are found between the two polarizations of some spikes, and drastic v ariations in the degree of polarization with the frequency, even reversal o f the polarizations, are found.