US 6,784,620 B1 · Plasma filter

Abstract

A low/band/high pass filter includes first and second plasmas, each with a path for the flow of electromagnetic energy at frequencies above the plasma frequency. A path for the flow of electromagnetic energy is coupled to the second port of the first plasma and to a first port of the second plasma. The plasma frequency of the second plasma is greater than that of the first plasma. Energy below the plasma frequency of the first plasma is reflected from the first port of the first plasma, and energy above the plasma frequency of the second plasma propagates to the second plasma. That energy above the plasma frequency of the first plasma but below the plasma frequency of the second plasma reflects from the second plasma and is coupled out of the system. That energy at a frequency above the second plasma frequency propagates through the second plasma.

Claims33

Dependent claims

A frequency-sensitive apparatus, comprising:

a first path for flow of electromagnetic energy;
a first plasma, not sustained by said electromagnetic energy, lying in said first path, said first plasma having a first plasma frequency;
and
a second plasma, not sustained by said electromagnetic energy, lying in said first path, said second plasma having a second plasma frequency, different from said first plasma frequency.

1 more element

A frequency-sensitive apparatus, comprising:

a first plasma defining first and second electromagnetic ports, and a path for flow of electromagnetic energy between said first and second ports of said first plasma at frequencies lying above a plasma frequency of said first plasma;
a second plasma defining first and second electromagnetic ports, and a path for flow of electromagnetic energy between said first and second ports of said second plasma at frequencies lying above a plasma frequency of said second plasma;
a source of electromagnetic energy for generating electromagnetic waves including at least one component, said component having a frequency which is one of (a) below said first plasma frequency, (b) between said first and second plasma frequencies, and (c) above said second plasma frequency;
first directional coupling means including first, second, and third ports, for coupling signal in a directional manner from said first port exclusively to said second port, from said second port exclusively to said third port, and from said third port exclusively to said first port, said second port of said first directional coupling means being coupled to said first port of said first plasma, for coupling to said third port of said first directional coupling means at least that component of said electromagnetic energy which reflects from said first plasma;
second directional coupling means including first, second, and third ports, for coupling signal in a directional manner from said first port exclusively to said second port, from said second port exclusively to said third port, and from said third port exclusively to said first port, said first port of said second directional coupling means being coupled to said second port of said first plasma, and said second port of said second directional coupling means being coupled to said first port of said second plasma, for coupling to said third port of said second directional coupling means at least that component of said electromagnetic waves which reflects from said second plasma.

2 more elements

A apparatus, comprising:

a first plasma sustained by an energy source coupled to said first plasma;
first radio-frequency electromagnetic coupling means coupled to said first plasma, for defining first and second radio-frequency electromagnetic ports of said first plasma for flow of electromagnetic energy other than that of said sustaining energy source coupled to said first plasma;
a second plasma sustained by an energy source coupled to said second plasma;
second radio-frequency electromagnetic coupling means coupled to said second plasma, for defining first and second radio-frequency electromagnetic ports of said second plasma for flow of electromagnetic energy other than that of said sustaining energy source coupled to said second plasma;
and
a radio-frequency electromagnetic path extending from said second port of said first plasma to said first port of said second plasma, for coupling radio frequency electromagnetic waves between said second port of said first plasma and said first port of said second plasma.

3 more elements

A frequency-sensitive apparatus, comprising:

a first path for flow of electromagnetic energy;
a first plasma lying in said first path, said first plasma having a first plasma frequency;
and
a second plasma lying in said first path, said second plasma having a second plasma frequency, different from said first plasma frequency;
a source of electromagnetic energy coupled to said first path at a location adjacent said first plasma, for transmitting electromagnetic waves, including components having frequencies lying above said plasma frequency of said first plasma and other components having frequencies lying above said plasma frequency of said second plasma, along said path toward said first plasma and said second plasma;
electromagnetic signal coupling means coupled to said first path at a location lying between said first and second plasmas, for extracting said component of said electromagnetic energy at a frequency lying between said plasma frequency of said first plasma and said plasma frequency of said second plasma;
and
signal utilization means coupled to said first path at a location adjacent said second plasma and remote from said first plasma, for utilizing said component of said electromagnetic energy at a frequency lying above said plasma frequency of said second plasma.

5 more elements

An apparatus, comprising:

a first plasma defining first and second electromagnetic ports and an energizing port;
a first source of electrical energy coupled to said energizing port of said first plasma for sustaining said first plasma at a first plasma frequency;
a second plasma defining at least a first electromagnetic port and an energizing port;
a second source of electrical energy coupled to said energizing port of said second plasma for sustaining said second plasma at a second plasma frequency different from, and greater than, said first plasma frequency;
a connecting path for the flow of electromagnetic energy, said connecting path extending from said second electromagnetic port of said first plasma to said first electromagnetic port of said second plasma;
and
a source of electromagnetic energy at a frequency which is one of (a) lower than said first plasma frequency and (b) lies between said first plasma frequency and said second plasma frequency, said source of electromagnetic energy being coupled to said first electromagnetic port of said first plasma, whereby electromagnetic energy applied to said first electromagnetic port of said first plasma at said frequency lower than said first plasma frequency is reflected by said first plasma, and electromagnetic energy applied to said first electromagnetic port of said first plasma at said frequency lying between said first plasma frequency and said second plasma frequency is transmitted through said first plasma and reflected by said second plasma.

4 more elements

Dependencies are inferred from the claim text.

Plasma filter

Life of this patent

Plasma filter

Life of this patent

Abstract

Claims33