  The spatially confined evanescent microwave photonics have been proved to be
highly desirable in broad practical scenarios ranging from robust information
communications to efficient quantum interactions. However, the feasible
applications of these photonics modes are limited due to the lack of
fundamental understandings and feasible directional coupling approaches at
sub-wavelengths. Here, we experimentally demonstrate the efficient near-field
photonic routing achieved in waveguides composed of two kinds of
single-negative metamaterials. Without mimicking the polarization features, we
propose all-electric near-field metasource in subwavelength scale and exemplify
its near-field functions like Janus, Huygens and spin sources, corresponding to
time-reversal, parity-time and parity symmetries of its inner degree of
freedom. Our work furthers the understandings about optical near-field symmetry
and feasible engineering approaches of directional couplings, which would pave
the way for promising integrated mircrowave photonics devices.
