  Dwarf galaxies are characterised by a very low luminosity and low mass.
Because of significant accretion and ejection activity of massive black holes,
some dwarf galaxies also host low-luminosity active galactic nuclei (AGNs). In
a few dwarf AGNs, very long baseline interferometry (VLBI) observations have
found faint non-thermal radio emission. SDSS J090613.77+561015.2 is a dwarf AGN
owning an intermediate-mass black hole (IMBH) with a mass of $M_{BH} =
3.6^{+5.9}_{-2.3} \times 10^5 M_{sun}$ and showing a rarely-seen two-component
radio structure in its radio nucleus. To further probe their nature, i.e. the
IMBH jet activity, we performed additional deep observations with the European
VLBI Network (EVN) at 1.66 GHz and 4.99 GHz. We find the more diffuse emission
regions and structure details. These new EVN imaging results allow us to reveal
a two-sided jet morphology with a size up to about 150 mas (projected length
$\sim$140 pc) and a radio luminosity of about $3\times10^{38}$ erg s$^{-1}$.
The peak feature has an optically thin radio spectrum and thus more likely
represents a relatively young ejecta instead of a jet base. The EVN study on
SDSS J090613.77+561015.2 demonstrates the existence of episodic, relatively
large-scale and powerful IMBH jet activity in dwarf AGNs. Moreover, we
collected a small sample of VLBI-detected dwarf AGNs and investigated their
connections with normal AGNs. We notice that these radio sources in the dwarf
AGNs tend to have steep spectra and small linear sizes, and possibly represent
ejecta from scaled-down episodic jet activity.
