Bilinear synthesis of nonstationary signals impinging on a multiantenna receiver has been recently introduced. The distinction in the spatial signatures of the sources provides a vehicle to reduce noise and source signal interactions in the time-frequency domain, and hence improves signal synthesis. In this letter, we utilize another form of diversity for enhanced source time-frequency signal representations. It is shown that cross-polarization antennas can be used to mitigate cross terms via simple polarization averaging.