Indian Journal of Science and Technology

Abstract

Objectives: To analyse a High Power Microwave (HPM) source connected to a horn antenna by a mathematical model and feeding it with various pulse shapes to find its response. To estimate the E far-field produced and compare it with experimental measurements. Methods/Statistical analysis: A HPM source is built using spark gap switch and Marx generator. Efforts are made to reduce the rise time of the radiated pulse by experimentally varying the spark gap distance and using different gases as di-electric medium. A peaking switch was then designed that could achieve a rise time of 1 nS. The energy discharged at the spark gap (peaking switch) is radiated using a horn type antenna. Findings: In the numerous simulations it was found that a sharp rising edge of the radiated pulse can be achieved if we could minimize the peaking stage inductance. A sharp rising edge gives high peak radiated power resulting in higher E far-field intensity, which is useful for the intended applications of HPM systems. Experimental results to measure the E far-field were coherent with the mathematical model; however, in order to make the mathematical model more accurate with the practical results, a scaling factor was empirically derived. Application/Improvements: During the experiments a range field product (r.Efar-field ) of more than 200 kV was achieved. Although this compares well with some of the contemporary systems. It is much less than 7.2 MV reported elsewhere. To achieve it, some improvements are required to further reduce the rise time of radiated pulse. This can be done by better impedance matching of the radiating antenna with the peaking stage and improvement in the Marx generator switching stages .

Keywords: HPM, Pulser, PFN (Pulse Forming Network), Spark-Gap