A new modification is carried out on axial virtual cathode oscillator to improve the device performance. The device operates by virtual cathode theory to generate high power microwave from the interaction between energetic electron beam and virtual cathode field. The electrical parameters are measured to understand the behavior of the discharge by using nitrogen gas. The breakdown potential Vb against Pd is investigated. A single electric probe is used to measure and estimate the plasma parameters. The virtual cathode position is defined from the axial distribution of electron density, axial distribution of electric field and axial distribution of plasma potential. The position of virtual cathode has been estimated to be at about 2cm from the mesh anode which can be confirmed from the electric field changing its direction and from the maximum value of plasma density at that position. The exposed samples to microwave radiation ensure the effects of the microwave radiation on them.