Efficiency study of a 2.2-kV, 1-ns, 1-MHz pulsed power generator based on a drift-step-recovery diode

Nanosecond pulsed-power generators featuring high peak and average power are attractive for ultra-wideband radars in applications such as through-wall detection and ground penetration. The efficiency of the pulse production scheme has a major importance in battery operated devices. This paper presents an efficiency study of a 2.2-kV, 1 ns pulsed power circuit. The circuit consists of a power MOSFET serving as a prime switch and a fast drift-step recovery diode (DSRD) connected in parallel to the load. The MOSFET utilizes a low-voltage DC power supply to pump and pulse the DSRD in the forward and reverse directions. An additional low-current DC power supply is used to provide a voltage bias in order to balance the DSRD forward with respect to its reverse charge. In order to study the circuit´s efficiency, it was operated at a wide range of operating parameters, including the main and bias source voltages, and the trigger duration of the prime switch. A peak voltage of 2.2 kV with a rise-time of less than 1 ns and a rise-rate of 3 kV/ns was obtained, where the efficiency was 24%. A higher efficiency of 52% was obtained when the circuit was optimized to an output peak voltage of 1.15 kV. The circuit was operated in single-shot mode, as well as in bursts of up to 100 pulses at a repetition rate of 1 MHz. Thus, during the burst a peak and average power of 96.8 kW and 155 W, respectively, were obtained.