Electronic oven with ferrite rf rejection filters

Claim 2

A coupling structure for interconnecting a generator for generating RF energy of a predetermined ultrahigh RF frequency and a source of DC operating potentials having at least one terminal and a source of low frequency AC energy having at least one terminal, wherein the generator has an annular outer RF terminal and an inner RF terminal, said coupling structure comprising a hollow outer conductor coupled to the outer RF terminal of the generator and extending outwardly therefrom and terminating in an outer end, an inner conductor disposed in said outer conductor and coupled to the inner RF terminal of the generator and extending outwardly therefrom and terminating in an outer end adjacent to the outer end of said outer conductor, an insulating sleeve disposed within said outer conductor in surrounding relationship with said inner conductor, a pair of RF output terminals respectively coupled to said outer conductor and said inner conductor intermediate the generator RF terminals and said outer ends, means coupling the DC source terminal and the low frequency AC source terminal to the outer end of said inner conductor, a ferrite filter element disposed between said insulating sleeve and said inner conductor and in contact with each intermediate the outer end of said inner conductor and said generator output terminals and being constructed and arranged to provide high transmission losses at selected harmonics of the predetermined frequency, and a conductive filter element disposed between said insulating sleeve and said inner conductor and in contact with each adjacent to the outer end of said inner conductor and connected to said ferrite filter element and being constructed and arranged to cooperate with said insulating sleeve and said outer conductor for providing a low impedance bypass path between said inner and outer conductors at the predetermined frequency, whereby propagation of ultrahigh frequency energy at the predetermined frequency and selected harmonics thereof from the generator to the outer ends of said conductors is highly attenuated without interfering with the transmission of the DC operating potentials and the low frequency AC energy from the sources thereof to the generator.

Claim 3

The coupling structure set forth in claim 1, wherein said inner and outer conductors and said ferrite filter element are each cylindrical in shape and circular in cross section, the outer diameter of said ferrite filter element being such as to provide high attenuation of all of the harmonics of the predetermined frequency up to the seventh harmonic.

Claim 4

The coupling structure set forth in claim 1, wherein said inner and outer conductors and said conductive filter element are each cylindrical in shape and circular in cross section, the outer diameter of said conductive filter element being such as to provide a capacitive bypass path between said inner and outer conductors at the pre-determined frequency.

Claim 5

The coupling structure set forth in claim 1, wherein said inner and outer conductors and said ferrite filter element and said conductive filter element are all cylindrical in shape and circular in cross section, the outer diameters of said ferrite filter element and said conductive filter element being substantially equal to each other.

Claim 6

The coupling structure set forth in claim 1, wherein said outer conductor overlaps said conductive filter element a distance not greater than one-quarter of the wavelength of the predetermined frequency.

Claim 7

The coupling structure set forth in claim 1, wherein said inner conductor comprises an externally threaded rod, said ferrite filter element and said conductive filter element each being cylindrical in shape and having an internally threaded opening extending axially therethrough, said inner conductor being threadedly engaged with the internally threaded openings through said ferrite filter element and saiD conductive filter element for coupling said filter elements to said inner conductor.

Claim 8

A coupling structure for interconnecting a generator for generating RF energy of a predetermined ultrahigh RF frequency and a source of DC operating potentials having at least one terminal and a source of low frequency AC energy having a pair of terminals, wherein the generator has an annular outer RF terminal and an inner RF terminal and a low frequency AC terminal, said coupling structure comprising a first hollow outer conductor coupled to the outer RF terminal of the generator and extending outwardly therefrom and terminating in an outer end, a first inner conductor disposed in said outer conductor and coupled to the inner RF terminal of the generator and extending outwardly therefrom and terminating in an outer end adjacent to the outer end of said outer conductor, a first insulating sleeve disposed within said outer conductor in surrounding relationship with said inner conductor, a pair of RF output terminals respectively coupled to said outer conductor and said inner conductor intermediate the generator RF terminals and said outer ends, means coupling one of said low frequency AC source terminals and one of said DC source terminals to the outer end of said inner conductor, a first ferrite filter element disposed between said first insulating sleeve and said inner conductor and in contact with each intermediate the outer end of said inner conductor and said generator output terminals and being constructed and arranged to provide high transmission losses at selected harmonics of the predetermined frequency, a first conductive filter element disposed between said first insulating sleeve and said inner conductor and in contact with each adjacent to the outer end of said inner conductor and connected to said ferrite filter element and being constructed and arranged to cooperate with said insulating sleeve and said outer conductor for providing a low impedance bypass path between said inner and outer conductors at the predetermined frequency, a second hollow outer conductor coupled to said one output terminal of said generator and disposed adjacent to said low frequency AC input terminal and extending outwardly therefrom and terminating in an outer end, a second inner conductor disposed in said second outer conductor and coupled to said low frequency AC input terminal of said generator and extending outwardly therefrom and terminating in an outer end adjacent to the outer end of said second inner conductor, a second insulating sleeve disposed within said second outer conductor in surrounding relationship with said second inner conductor, means coupling the other of said low frequency AC source terminals to the outer end of said second inner conductor, a second ferrite filter element disposed between said second insulating sleeves and said second inner conductor and in contact with each intermediate the outer end of said second inner conductor and said generator low frequency AC input terminal and being constructed and arranged to provide high transmission losses at selected harmonics of the predetermined frequency, and a second conductive filter element disposed between said second insulating sleeve and said second inner conductor and in contact with each adjacent to the outer end of said second inner conductor and connected to said second ferrite filter element and being constructed and arranged to cooperate with said second insulating sleeve and said second outer conductor for providing a low impedance bypass path between said second inner and outer conductors at the predetermined frequency, whereby propagation of ultrahigh frequency energy at the predetermined frequency and selected harmonics thereof from the generator to the outer ends of said first and second conductors is highly attenuated without interfering with the transmission of the DC operating potentials and the low frequency AC energy from the sources thereof to the generator.

Claim 9

A coupling structure for interconnecting a generator for generating RF energy of a predetermined ultrahigh RF frequency and a source of DC operating potentials having at least one terminal and a source of low frequency AC energy having a pair of terminals, wherein the generator has an annular outer RF terminal and an inner RF terminal and a low frequency AC terminal, said coupling structure comprising a first hollow outer conductor coupled to the outer RF terminal of the generator and extending outwardly therefrom and terminating in an outer end, a first inner conductor disposed in said outer conductor and coupled to the inner RF terminal of the generator and extending outwardly therefrom and terminating in an outer end adjacent to the outer end of said outer conductor, a first insulating sleeve disposed within said outer conductor in surrounding relationship with said inner conductor, a pair of RF output terminals respectively coupled to said outer conductor and said inner conductor intermediate the generator RF terminals and said outer ends, means coupling one of said low frequency AC source terminals and one of said DC source terminals to the outer end of said inner conductor, a first ferrite filter element disposed between said first insulating sleeve and said inner conductor and in contact with each intermediate the outer end of said inner conductor and said generator output terminals and being constructed and arranged to provide high transmission losses at selected harmonics of the predetermined frequency, a first conductive filter element disposed between said first insulating sleeve and said inner conductor and in contact with each adjacent to the outer end of said inner conductor and connected to said ferrite filter element and being constructed and arranged to cooperate with said insulating sleeve and said outer conductor for providing a low impedance bypass path between said inner and outer conductors at the predetermined frequency, a second hollow outer conductor coupled to said one output terminal of said generator and disposed adjacent to said low frequency AC input terminal and extending outwardly therefrom and terminating in an outer end, a second inner conductor disposed in said second outer conductor and coupled to said low frequency AC input terminal of said generator and extending outwardly therefrom and terminating in an outer end adjacent to the outer end of said second inner conductor, a second insulating sleeve disposed within said second outer conductor in surrounding relationship with said second inner conductor, means coupling the other of said low frequency AC source terminals to the outer end of said second inner conductor, a second ferrite filter element disposed between said second insulating sleeves and said second inner conductor and in contact with each intermediate the outer end of said second inner conductor and said generator low frequency AC input terminal and being constructed and arranged to provide high transmission losses at selected harmonics of the predetermined frequency, and a second conductive filter element disposed between said second insulating sleeve and said second inner conductor and in contact with each adjacent to the outer end of said second inner conductor and connected to said second ferrite filter element and being constructed and arranged to cooperate with said second insulating sleeve and said second outer conductor for providing a low impedance bypass path between said second inner and outer conductors at the predetermined frequency, whereby propagation of ultrahigh frequency energy at the predetermined frequency and selected harmonics thereof from the generator to the outer ends of said first and second conductors is highly attenuated without interfering with the transmission of the DC operating potentials and the low frequency AC energy from the sources thereof to the generator.

Claim 10

The cOupling structure as set forth in claim 7, wherein said first ferrite filter element is identical in construction to said second filter element, and wherein said first conductive filter element is identical in construction to said second conductive filter element.

Claim 11

An RF rejection filter for highly attenuating a predetermined ultrahigh frequency and selected harmonics thereof, said filter assembly comprising a coaxial transmission line section including a hollow outer conductor and an inner conductor disposed in said outer conductor, a ferrite filter element disposed in contact with said inner conductor and being constructed and arranged to provide high transmission losses at selected harmonics of the predetermined frequency, a conductive filter element disposed in contact with said inner conductor and connected to said ferrite filter element and being constructed and arranged to provide a low impedance bypass path between said inner and outer conductors at the predetermined frequency, and an insulating sleeve disposed between said filter elements and said outer conductor and in contact with each, said filter elements cooperating with each other and with said inner and outer conductors to form a filter for highly attenuating said predetermined frequency and selected harmonics thereof.

Claim 12

An RF rejection filter for highly attenuating a predetermined ultrahigh frequency and selected harmonics thereof, said filter assembly comprising a coaxial transmission line section including a hollow outer conductor and an inner conductor disposed in said outer conductor, a ferrite filter element disposed in contact with said inner conductor and being constructed and arranged to provide high transmission losses at selected harmonics of the predetermined frequency, a conductive filter element disposed in contact with said inner conductor and connected to said ferrite filter element and being constructed and arranged to provide a low impedance bypass path between said inner and outer conductors at the predetermined frequency, and an insulating sleeve disposed between said filter elements and said outer conductor and in contact with each, said filter elements cooperating with each other and with said inner and outer conductors to form a filter for highly attenuating said predetermined frequency and selected harmonics thereof.

Claim 13

The RF rejection filter set forth in claim 9, wherein said inner and outer conductors and said ferrite filter element are each cylindrical in shape and circular in cross section, the outer diameter of said ferrite filter element being such as to provide high attenuation of all of the harmonics of the predetermined frequency up to the seventh harmonic.

Claim 14

The RF injection filter set forth in claim 9, wherein said inner and outer conductors and said conductive filter element are each cylindrical in shape and circular in cross section, the outer diameter of said conductive filter element being such as to provide a capacitive bypass path between said inner and outer conductors at the predetermined frequency.

Claim 15

The RF rejection filter set forth in claim 9, wherein said inner and outer conductors and said ferrite filter element and said conductive filter element are all cylindrical in shape and circular in cross section, the outer diameters of said ferrite filter element and said conductive filter element being substantially equal to each other.

Claim 16

The RF rejection filter set forth in claim 9, wherein said outer conductor overlaps said conductive filter element a distance not greater than one-quarter of the wavelength of the predetermined frequency.

Claim 17

The RF rejection filter set forth in claim 9, wherein said inner conductor comprises an externally threaded rod, said ferrite filter element and said conductive filter element each being cylindrical in shape and having an internally threaded opening extending axially therethrough, said inner conductor being threadedly engaged with the internally threaded openings through said ferrite filter element and said conductive filter element for coupling said filter elements to said inner conductor.