Generation of Flexible High Power Pulsed Waveforms

Patent metadata

Field	Value
Publication number	US-2016197215-A1
Application number	US-201514588467-A
Country	US
Kind code	A1
Filing date	Jan 2, 2015
Priority date	Jan 2, 2015
Publication date	Jul 7, 2016
Grant date	—

Abstract

A method for generating high power pulsed RF waveforms comprises the steps of charging a transmission line in a pulse forming network with a high-voltage and discharging the voltage on the transmission line to ground utilizing a gallium nitride photoconductive switch.

First claim

What is claimed is:

1 . A method for generating high power pulsed RF waveforms, comprising the steps of:
charging a transmission line in a pulse forming network with a high-voltage; and, discharging the voltage on the transmission line to ground utilizing a gallium nitride photoconductive switch.

2 . The method of claim 1 , wherein the gallium nitride photoconductive switch is activated by laser pulses from a picosecond laser.

3 . The method of claim 2 , wherein said gallium nitride photoconductive switch is activated by laser pulses having a pulse width in a picosecond range.

4 . The method of claim 3 , wherein activation of the gallium nitride photoconductive switch by laser pulses forms multiple RF pulses.

5 . The method of claim 4 , wherein the multiple RF pulses from the picosecond have equal interpulse spacings.

6 . The method of claim 4 , wherein the multiple RF pulses from the picosecond have variable interpulse spacings.

7 . The method of claim 5 , wherein, the charged transmission line is not significantly discharged through the gallium nitride photoconductive switch upon actuation thereof.

8 . The method of claim 7 , wherein picosecond laser pulses are delivered to the gallium nitride photoconductive switch and wherein the gallium nitride photoconductive switch is closed in at least one of a nanosecond and a picosecond time frame responsive to delivered picosecond laser pulses.

9 . The method of claim 8 , wherein the at least one nanosecond and picosecond time frame for the gallium nitride photoconductive switch closure permits rapid periodic discharging of the transmission line prior to the time that the energy stored in the transmission line has been depleted, thereby permitting the generation of rapid high power RF pulses.

10 . The method of claim 9 , wherein an effective operating frequency of the RF pulses generated is correlated to the interpulse spacings due to an interference of the pulses within the pulse forming network.

11 . The method of claim 10 , wherein the interpulse spacings are equal, and wherein the effective operating frequency is dependent upon the equal interpulse spacings, thereby permitting gigahertz operating frequencies.

12 . The method of claim 11 , wherein the operating frequency is tuned by changing the interpulse spacings, whereby a large frequency tuning range is achieved.

13 . The method of claim 10 , wherein different interpulse spacings result in differing frequencies mixed in the pulse forming network to generate a waveform having flexible characteristics including the position of notches in the waveform characteristic.

14 . The method of claim 13 , wherein the RF waveform output is modulated by modulation of the laser.

15 . A waveform flexible photoconductive switch-based high power RF pulse generator having a photoconductive switch with a sub-nanosecond response time, comprising:
a gallium nitride photoconductive switch; a laser for activating said gallium nitride photoconductive switch; an RF pulse forming network including a transmission line connected to said gallium nitride photoconductive switch, wherein activation of the switch discharges said transmission line to ground; and a high-voltage source coupled to said gallium nitride photoconductive switch.

16 . The high power RF generator of claim 15 , wherein said RF generator includes an antenna, and wherein said pulse forming network includes an impedance transformer between said transmission line and said antenna.

17 . The high power RF generator of claim 15 , wherein said laser produces multiple picosecond activation pulses and wherein said picosecond laser pulses result in nanosecond wide resulting RF pulses due to the sub-nanosecond response time of the gallium nitride photoconductive switch.

18 . The high power RF generator of claim 17 , wherein varying the interpulse spacing of the multiple picosecond activation pulses changes a frequency of the output from said high power RF generator.

19 . The high power RF generator of claim 18 , wherein said pulse forming network includes a transformer and wherein frequency output of said high power RF generator can be changed without altering said transformer.

20 . The high power RF generator of claim 18 , wherein said interpulse spacing is tailored to provide high power RF pulses having variable frequency, power and repetition rate characteristics utilizing a single switching element.

21 . The high power RF generator of claim 15 , wherein a short carrier lifetime associated with the gallium arsenide switch permits achieving high pulse repetition rates in the tens-to-hundreds of megahertz.

22 . The high power RF generator of claim 15 , wherein a short carrier lifetime associated with the gallium arsenide switch permits generation of multiple RF pulses prior to the time that said transmission line is discharged.

23 . The high power RF generator of claim 22 , wherein the generation of multiple RF pulses prior to the time that said transmission line is discharged permits increasing an amount of energy on a target.

24 . The high power RF generator of claim 15 , wherein a short carrier lifetime associated with gallium nitride permits generation of pulse repetition rates that can match those associated with any target, provides gigahertz operational frequencies, and increases the tuning range of the high power RF generator by 2 to 3 times over that achievable utilizing a silicon switch.

Assignees

• Bae Sys Inf & Elect Sys Integ

Inventors

• Kozyrev Alexander
• Mcgeehan John
• Morel Yannick

Classifications

• H10F30/00

  Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors · CPC title

• H10F77/1246 Primary

  III-V nitrides, e.g. GaN · CPC title

• H01L31/03044 Primary

  Electricity · mapped topic

• H03K17/78

  using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled · CPC title

• H01L31/09

  Electricity · mapped topic