Radiation Mechanism And Control Method Of Radio Frequency Harmonics In Armored Target Metal Junction

With nonlinear harmonic radiation characteristics in the microwave radiation of radio frequency, armored targets can be detected and tracked by harmonic radar systems. In this thesis, under the background of developing stealth technologies for armored targets, the mechanism and control methods of harmonic radiation in metal-oxide-metal junctions and metal-oxide junctions are analyzed. Experiments results are given to verify the proposed conclusions. The main contents are as follows.Firstly, the barrier model of the metal junction is established, and its nonlinear characteristics are analyzed. In the microwave radiation of radio frequency, metal junctions generate not only the fundamental wave but also the harmonic waves, of which the third harmonic wave is the strongest. A direct-current bias voltage is produced and causes the dynamic balancing process of the direct-current bias voltage.Secondly, the influence of the size and material of metal junctions on the junction third harmonic wave generation is analyzed. The barrier height between the metal and the oxide layer surface would be changed when the material of the metal changes. Based on the theoretical and simulation results, it is concluded that when the thickness of the insulating film grows larger, the contact area between the metal and the oxide goes smaller, or the barrier height between the metal and the oxide surface goes larger, a weaker third harmonic wave is obtained.At last, a measurement system for the third harmonic wave is built to evaluate the conclusions obtained. The experimental results show that when the barrier height between the metal and the oxide surface goes larger, or the contact area of the metal and the oxide goes smaller, the third harmonic signal radiated by the metal junction becomes weaker. The measurement results coincide with theoretical analysis results.