High power microwave expander for producing fast rise time pulses
AssigneeThe United States of America as represented by the Secretary of the Army
InventorsMark D. Berry, Robert J. Tan, Robert V. Garver
Life of this patent
Estimating the term…
Abstract
An high power microwave expander is provided which decreases the rise time of rf pulses. The expander is a transmission line in which internal conductors are separated and tapered to provide a spark gap with high isolation characteristics at low power. The arcing threshold of the spark gap can be adjusted by varying the internal pressure of the transmission line, injecting a gas such as helium into the transmission line and by providing free electrons in close proximity to the spark gap.
Claims28
An apparatus for producing high power microwave pulses that have extremely fast rise times compared to rise times of a signal delivered from a microwave signal source comprising:
- an air coaxial transmission line having input and output ends and a predetermined internal pressure, said coaxial transmission line having a spark gap ranging from about 0.01-0.10 inch positioned between said input and output ends;
- means for adjusting the internal pressure of said coaxial transmission line so that the arcing threshold of said spark gap can be varied;
- means for coupling said microwave signal source to said input end of said coaxial transmission line;
- and
- means for coupling a load to said output end of said coaxial transmission line;
- whereby
- said microwave signal source delivers an input pulse, having a rise time, via said input end of said transmission line to the spark gap, the spark gap presenting a high impedance during the initial rise of the input pulse until the power of the input pulse reaches an arcing threshold of said spark gap causing said spark gap to arc, resulting in an output pulse delivered to said load that has a rise time that is faster than the rise time of the input pulse.
An apparatus for producing high power microwave pulses that have extremely fast rise times compared to rise times of a signal delivered from a microwave signal source comprising:
- an air coaxial transmission line having input and output ends, said coaxial transmission line having a spark gap ranging from about 0.01-0.10 inch positioned between said input and output ends;
- a first center conductor in said coaxial transmission line having a first end tapered to form a substantially conical tip having an apex angle ranging from about 10.degree.-112.degree. and a second end;
- a second center conductor in said coaxial transmission line having a first end tapered to form a substantially conical tip having an apex angle ranging from about 10.degree.-112.degree. and a second end, the first end of said first center conductor separated from the first end of said second center conductor creating said spark gap;
- means for coupling said microwave signal source to said input end of said coaxial transmission line;
- and
- means for coupling a load to said output end of said coaxial transmission line;
- whereby
- said microwave signal source delivers an input pulse, having a rise time, via said input end of said coaxial transmission line to the spark gap, the spark gap presenting a high impedance during the initial rise of the input pulse until the power of the input pulse reaches an arcing threshold of said spark gap causing said spark gap to arc, resulting in an output pulse delivered to said load that has a rise time that is faster than the rise time of the input pulse.
An apparatus for producing high power microwave pulses that have extremely fast rise times compared to rise times of a signal delivered from a microwave signal source comprising;
- a stripline transmission line having input and output ends, said stripline transmission line tuned to the signal delivered from said microwave signal source having a wavelength lambda;
- means for coupling said microwave signal source to said input end of said stripline transmission line;
- means for coupling a load to said output end of said stripline transmission line;
- a branch stripline having a one quarter lambda length portion connected in shunt to said stripline transmission line and a one half lambda length portion with a spark gap formed between opposing ends of the portions;
- and
- means for providing a bias voltage across the spark gap.
An apparatus for producing high power microwave pulses that have extremely fast rise times compared to rise times of a signal delivered from a microwave signal source comprising:
- a rectangular waveguide transmission line having input and output ends and a predetermined internal pressure, said waveguide transmission line having a spark gap ranging from about 0.01-0.10 inch positioned between said input and output ends;
- means for coupling said microwave signal source to said input end of said waveguide transmission line;
- and
- means for coupling a load to said output end of said waveguide transmission line;
- whereby
- said microwave signal source delivers an input pulse, having a rise time, via said input end of said waveguide transmission line to the spark gap, the spark gap presenting a high impedance during the initial rise of the input pulse until the power of the input pulse reaches an arcing threshold of said spark gap causing said spark gap to arc, resulting in an output pulse delivered to said load that has a rise time that is faster than the rise time of the input pulse.
An apparatus for producing high power microwave pulses that have extremely fast rise times compared to rise times of a signal delivered from a microwave signal source comprising:
- a coaxial transmission line having a predetermined internal pressure;
- a first center conductor in said coaxial transmission line having a first end tapered to form a substantially conical tip having an apex angle ranging from about 10.degree.-112.degree. and a second end;
- a second center conductor in said coaxial transmission line having a first end tapered to form a substantially conical tip having an apex angle ranging from about 10.degree.-112.degree. and a second end;
- the first end of said first center conductor separated from the first end of said second center conductor creating a spark gap ranging from about 0.01-0.10 inch;
- means for adjusting the internal pressure of said coaxial transmission line so that an arcing threshold of the spark gap can be varied;
- means for providing a bias voltage across the spark gap so that the arcing threshold of the spark gap can be varied;
- means for injecting a gas into said coaxial transmission line so that arcing of the spark gap is promoted when the arcing threshold of said spark gap is reached;
- means for introducing electrons into the spark gap so that consistent arcing of the spark gap is achieved when the arching threshold is reached;
- means for coupling a load to the second end of said second center conductor;
- and
- means for coupling said microwave signal source to the second end of said first center conductor.
An apparatus for producing high power microwave pulses that have extremely fast rise times compared to rise times of a signal delivered from a microwave signal source comprising:
- a waveguide section having first and second ends and a predetermined internal pressure;
- means for coupling a microwave signal source to the first end of said waveguide section, said microwave signal source generating an electric field in said waveguide at a wavelength lambda;
- means for coupling a load to the second end of said waveguide section;
- a first coaxial transmission line having a first end connected in shunt to a first side wall of said waveguide section and a shorted end, said first coaxial transmission line having an adjustably positionable center conductor that is tapered to form a substantially conical tip;
- a second coaxial transmission line having a first end connected in shunt to a second side wall of said waveguide section diametrically opposing said first end of said first coaxial transmission line and a shorted end, said second coaxial transmission line having an adjustably positionable center conductor that is tapered to form a substantially conical tip, said center conductors of said coaxial transmission lines in axial alignment and separated from one another creating a spark gap ranging from about 0.01-0.10 inch.
Dependencies are inferred from the claim text.