Two pin -n and one n-inn silicon microstrip detectors were radiation-damaged and tested in a beam. A comparison was made between the pin -n and the n-inn in high resistivity wafers, and the pin -n in a low and a high resistivity wafer. The charge collection showed a clear difference in the n-inn and the pin -n detectors, which suggested that the signals were shared between strips more in the irradiated pin -n detectors. Although a difference of the low and the high resistivity wafers was observed in the body capacitance measurement, little difference was observed in the beamtest results.