This paper proposes the study of an inverted microstrip plasma-based reconfigurable antenna. The scope is to generate controlled microplasma inside the cavity between the antenna ground plane and its main conductor. This plasma will modify the resonant frequency of the antenna. The interest of using a plasma discharge as an active reconfigurable element is its switching time and mainly its capability of handling high microwave power. It was demonstrated, theoretically, that the reconfiguration frequency of a microstrip patch antenna with a microdischarge in its cavity, depends on the electron density of the plasma. Furthermore, a prototype of an X-Band inverted microstrip patch antenna, which integrates a microdischarge, was implemented. The measured frequency excursion for this prototype was 180 MHz.