Focal plane array Doppler imaging with per-pixel CW-Doppler receiver array

There are at least 2 reasons why the author begins with the per-pixel CW-Doppler receiver array for focal plane array (FPA) architecture, One is that, in FPA for real time echo-orthography (means camera-like picture taking, not an echo-tomography (cross-section image) we are familiar with), illumination (transmission) must be non- or omni-directional, receive-only directivity determines desired-to-clutter ratio which in the case of B-mode estimated is relatively poor, however in the Doppler domain no stronger clutter than flowing fluid is expected which will cause the receive-only directivity image to be reasonable or acceptable. The other is that CW-Doppler per-channel electronics can be so simple as we experienced in the fetal heart beat detector even for personal use. The philosophy of the FPA essentially is to have no "beam-forming" business at all, which can be done either by lens or element directivity, the simplicity of channel (per pixel) electronics is inevitable and essential.