There is a strong need for wideband and sensitive receivers in the terahertz (THz) region. When considering imaging issues, cross talk between neighbor pixels is of key importance. The case of continuous wave imaging with superconducting hot-electron bolometers as heterodyne mixing sensors is considered, when the coupling to the incident THz radiation is accomplished by means of planar multi-octave self-complementary log-periodic antennas. The minimum distance between two antennas is considered in terms of resolution, diffraction, and electromagnetic coupling criteria. Back-end cross talk between the output lines at the intermediate frequency is briefly addressed.