Characterization of an X-Band Metamaterial Slow Wave Structure for HPM Applications

In this article, we have characterized an X- band complementary electric split-ring resonator (CeSRR) based metamaterial (MTM) slow-wave structure (SWS), suitable for high-efficiency vacuum electron devices (VEDs). The MTM SWS consists of an array of CeSRR and a circular waveguide that propagates below the cut-off frequency of an empty waveguide in the TM01 mode. The surface current distribution has been used to predict the resonance frequency of the CeSRR. An equivalent circuit approach has been used here to obtain its equivalent circuit capacitance and inductance per unit length, which is used further to analyze the dispersion characteristics and interaction impedance of the MTM SWS. The electromagnetic (EM)simulation result showed that the dispersion bandwidth ranges from 9.53 to 9.78 GHz, and the average interaction impedance is greater than
$550~\Omega $
. Furthermore, we have designed, EM simulated, and experimentally characterized the proposed X- band MTM SWS. The experimental transmission coefficient (
$S_{21}$
) has been found approximately consistent with the EM simulated values.