Search

High-repetition-rate nanosecond pulses are used widely in many fields, and pulses of different polarities have different effects. A new pulse-generator structure is proposed based on an improved Blumlein pulse-forming line (BPFL) and a transmission-line transformer (TLT). The proposed structure generates pulses with polarity that can be adjusted among positive, negative, and bipolar. A modular design is used for the generator. In each module, three groups of solid-state switches are used to control the BPFL. By adjusting the timing of the control signal, the BPFL can generate high-repetition-rate nanosecond primary pulses with adjustable polarity. These primary pulses are then transmitted to the load through the TLT with amplification and superposition. The pulse-forming process is analyzed theoretically for matched impedance. The strategy for controlling the switches is also illustrated. In addition, the feasibility of the proposed generator is verified by simulations and experiments. Finally, a four-stage prototype is developed that can produce pulses with amplitudes of 0–10 kV, a width of 30 ns, repetition rates up to 200 kHz and adjustable polarity. [ABSTRACT FROM AUTHOR]

A high pulse repetition frequency (PRF) nanosecond pulse generator based on Blumlein pulse forming line (BPFL) and transmission line transformer (TLT) is proposed in this paper. The generator combines the BPFL characteristic, which is used to generate a narrow, high PRF pulse, with the excellent performance at high frequency of a transmission line transformer. A modular structure was adopted for this design. The primary pulse produced by the BPFL in each module will output to the load through the TLT amplifier; further, the output of multiple modules can be cascaded to improve the load voltage and output power. Moreover, this reduces the ratio of the output impedance and the input impedance of the TLT, making the generator more suitable for light loads. A microstrip line was used for the transmission line, which makes it possible to match random loads. Additionally, the size of generator was greatly reduced to realize a compact design. MOSFETs were used in the generator to facilitate the control of both the amplitude and PRF of the output. A two-stage laboratory prototype was fabricated to verify the performance of the proposed topology. As a result, the generator produced pulses for matched loads with amplitudes of 0?2.5 kV, pulse width of 20 ns, and repetition frequencies of 0?10 kHz. The generator can be used as a hardware foundation for research on the biomedical effects of exposure to high PRF nanosecond pulse electric fields. [ABSTRACT FROM AUTHOR]

Several series and parallel Blumlein-type striplines designed on multilayered printed circuit board (PCB) are connected to match different impedance loads with different pulsewidths to develop a high-voltage nanosecond pulse generator for investigating the biological effects of a nanosecond pulsed electric field. First, the principle of a multistage series–parallel Blumlein stripline system is described. In particular, the multilayered strip transmission line is designed on the five-layered PCB to minimize the volume of the system whose maximum size is 300 mm (length) $\times \,\, 260$ mm (width) $\times \,\, 154$ mm (height), and the gate resistor capacitor and diode active equalizing circuit is used as the dynamic/static balancing tactic. Then, a single-stage Blumlein-type stripline and some multistage series–parallel Blumlein-type stripline are established to test their performance. As a result, the nanosecond pulse generator produces a rectangular pulse on a matched resistor load, with an amplitude of 0–1.7 kV, a pulsewidth of integer multiples of 100 ns, a rise time of $\sim 20$ ns or less, and a repetition frequency of 0 to several kHz. A variety of biomedical loads can be matched by parallel stacking mode, which will facilitate the analysis of the biological effects of the nanosecond pulsed electric field. [ABSTRACT FROM AUTHOR]