  We describe a simple experimental method to detect electron paramagnetic
resonance (EPR) in polycrystalline 2,2-diphenyl-1-picrylhydrazyl (DPPH) sample,
the standard g-marker for EPR spectroscopy, without using a cavity resonator or
a prefabricated waveguide. It is shown that microwave(MW) current injected into
a layer of silver paint coated on an insulating DPPH sample is able to excite
the paramagnetic resonance in DPPH. As the applied dc magnetic field H is
swept, the high-frequency resistance of the Ag-paint layer, measured at room
temperature with a single port impedance analyzer in the MW frequency range 1
to 2.5 GHz, exhibits a sharp peak at a critical value of the dc field (H =
Hres) while the reactance exhibits a dispersion-like behavior around the same
field value for a given frequency. Hres increases linearly with the frequency
of MW current. We interpret the observed features in the impedance to EPR in
DPPH driven by the Oersted magnetic field arising from the MW current in the
Ag-paint layer. We also confirm the occurrence of EPR in DPPH independently
using a coplanar waveguide-based broadband technique. This technique has the
potential to investigate other EPR active inorganic and organic compounds.
