Smart microwave packaging structures

Claim 3

The method of claim 1 wherein said microwave-heatable load is a food stuff or snack.

Claim 4

The method of claim 1 in which the at least one active switching device switches such as to shift into resonance with the load during said predetermined portion of the heating cycle whereby to enhance heating of the load.

Claim 5

The method of claim 1 in which the at least one active switching device switches such as to shift into anti-resonance with the load during said predetermined portion of the heating cycle whereby to inhibit heating of the load.

Claim 8

An active element capable of modifying the microwave heating of a microwave heatable load, said active element having microwave reflective boundaries corresponding to a shape selected from strips and slots, said boundaries providing guidance of microwaves leading to specific interference effects by interaction with the microwave heatable load, with dielectric materials when adjacent thereto, and with dielectric components of a microwave cavity or oven when the said active element is located beneath said load and when the load and element are supported thereby, said microwave reflective boundaries being formed by variation of constitutive parameters across the boundaries of the active element to provide contiguous regions with differing constitutive parameters selected from differing dielectric constants, differing magnetic permeabilities, and differing conductivities between the regions, and said interference effects being selected from constructive interference to provide resonant intensification of the microwave fields for intensification of microwave heating of the load, and from destructive interference to provide anti-resonant reduction of the microwave field intensities for reduced microwave heating of the load, the said active element being shaped in the form of a slot or strip, and for resonance p=π(m.sup.2 /a.sup.2 +n.sup.2 /b.sup.2).sup.1/2 where p is the transverse wave number, also determined by p=2 π√.di-elect cons..sub.eff /λ.sub.o, a is the length or circumference of the element, b is the width of the element, m and n are mode orders, m being a positive integer or zero if n is non-zero, and n being a positive integer or zero if m is non-zero, .di-elect cons. eff is the effective dielectric constant adjacent to the element, and λ o is the free space wavelength of the microwaves.

Claim 9

An active element capable of modifying the microwave heating of a microwave heatable load, said active element having microwave reflective boundaries corresponding to a shape selected from strips and slots, said boundaries providing guidance of microwaves leading to specific interference effects by interaction with the microwave heatable load, with dielectric materials when adjacent thereto, and with dielectric components of a microwave cavity or oven when the said active element is located beneath said load and when the load and element are supported thereby, said microwave reflective boundaries being formed by variation of constitutive parameters across the boundaries of the active element to provide contiguous regions with differing constitutive parameters selected from differing dielectric constants, differing magnetic permeabilities, and differing conductivities between the regions, and said interference effects being selected from constructive interference to provide resonant intensification of the microwave fields for intensification of microwave heating of the load, and from destructive interference to provide anti-resonant reduction of the microwave field intensities for reduced microwave heating of the load, the said active element being shaped in the form of a slot or strip, and for resonance p=π(m.sup.2 /a.sup.2 +n.sup.2 /b.sup.2).sup.1/2 where p is the transverse wave number, also determined by p=2 π√.di-elect cons..sub.eff /λ.sub.o, a is the length or circumference of the element, b is the width of the element, m and n are mode orders, m being a positive integer or zero if n is non-zero, and n being a positive integer or zero if m is non-zero, .di-elect cons. eff is the effective dielectric constant adjacent to the element, and λ o is the free space wavelength of the microwaves.

Claim 10

An active element capable of modifying the microwave heating of a microwave heatable load, said active element having microwave reflective boundaries corresponding to a shape selected from circular patches and apertures, said boundaries providing guidance of microwaves leading to specific interference effects by interaction with the microwave heatable load, with dielectric materials when adjacent thereto, and with dielectric components of a microwave cavity or oven when the said active element is located beneath said load and when the load and element are supported thereby, said microwave reflective boundaries being formed by variation of constitutive parameters across the boundaries of the active element to provide contiguous regions with differing constitutive parameters selected from differing dielectric constants, differing magnetic permeabilities, and differing conductivities between the regions, and said interference effects being selected from constructive interference to provide resonant intensification of the microwave fields for intensification of microwave heating of the load, and from destructive interference to provide anti-resonant reduction of the microwave field intensities for reduced microwave heating of the load, the said active element being shaped in the form of a circular aperture or patch, and for resonance p=j'.sub.n,m /a where p is the transverse wave number, also determined by p=2 π√.di-elect cons..sub.eff /λ.sub.o o j' n ,m are the zeros of the derivative of the Bessel function of the order n, and a is the radius of the aperture or patch .di-elect cons. eff is the effective dielectric constant adjacent to the element, and λ o is the free space wavelength of the microwaves.

Claim 11

An active element capable of modifying the microwave heating of a microwave heatable load, said active element having microwave reflective boundaries corresponding to a shape selected from circular patches and apertures, said boundaries providing guidance of microwaves leading to specific interference effects by interaction with the microwave heatable load, with dielectric materials when adjacent thereto, and with dielectric components of a microwave cavity or oven when the said active element is located beneath said load and when the load and element are supported thereby, said microwave reflective boundaries being formed by variation of constitutive parameters across the boundaries of the active element to provide contiguous regions with differing constitutive parameters selected from differing dielectric constants, differing magnetic permeabilities, and differing conductivities between the regions, and said interference effects being selected from constructive interference to provide resonant intensification of the microwave fields for intensification of microwave heating of the load, and from destructive interference to provide anti-resonant reduction of the microwave field intensities for reduced microwave heating of the load, the said active element being shaped in the form of a circular aperture or patch, and for resonance p=j'.sub.n,m /a where p is the transverse wave number, also determined by p=2 π√.di-elect cons..sub.eff /λ.sub.o o j' n ,m are the zeros of the derivative of the Bessel function of the order n, and a is the radius of the aperture or patch .di-elect cons. eff is the effective dielectric constant adjacent to the element, and λ o is the free space wavelength of the microwaves.

Claim 12

An active element capable of modifying the microwave heating of a microwave heatable load, said active element having microwave reflective boundaries corresponding to a shape selected from circular rings and slots, said boundaries providing guidance of microwaves leading to specific interference effects by interaction with the microwave heatable load, with dielectric materials when adjacent thereto, and with dielectric components of a microwave cavity or oven when the said active element is located beneath said load and when the load and element are supported thereby, said microwave reflective boundaries being formed by variation of constitutive parameters across the boundaries of the active element to provide contiguous regions with differing constitutive parameters selected from differing dielectric constants, differing magnetic permeabilities, and differing conductivities between the regions, and said interference effects being selected from constructive interference to provide resonant intensification of the microwave fields for intensification of microwave heating of the load, and from destructive interference to provide anti-resonant reduction of the microwave field intensities for reduced microwave heating of the load, the said active element being shaped in the form of a circular ring or slot, and for resonance p=2n/(a+b) where p is the transverse wave number, also determined by p=2 π√.di-elect cons..sub.eff /λ.sub.o, with a being the inner radius of the circular ring or slot, b its outer radius and n being the mode order, and in particular a positive integer, .di-elect cons. eff is the effective dielectric constant adjacent to the element, and λ o is the free space wavelength of the microwaves.

Claim 13

An active element capable of modifying the microwave heating of a microwave heatable load, said active element having microwave reflective boundaries corresponding to a shape selected from circular rings and slots, said boundaries providing guidance of microwaves leading to specific interference effects by interaction with the microwave heatable load, with dielectric materials when adjacent thereto, and with dielectric components of a microwave cavity or oven when the said active element is located beneath said load and when the load and element are supported thereby, said microwave reflective boundaries being formed by variation of constitutive parameters across the boundaries of the active element to provide contiguous regions with differing constitutive parameters selected from differing dielectric constants, differing magnetic permeabilities, and differing conductivities between the regions, and said interference effects being selected from constructive interference to provide resonant intensification of the microwave fields for intensification of microwave heating of the load, and from destructive interference to provide anti-resonant reduction of the microwave field intensities for reduced microwave heating of the load, the said active element being shaped in the form of a circular ring or slot, and for resonance p=2n/(a+b) where p is the transverse wave number, also determined by p=2 π√.di-elect cons..sub.eff /λ.sub.o, with a being the inner radius of the circular ring or slot, b its outer radius and n being the mode order, and in particular a positive integer, .di-elect cons. eff is the effective dielectric constant adjacent to the element, and λ o is the free space wavelength of the microwaves.

Claim 14

An active element capable of modifying the microwave heating of a microwave heatable load, said active element having microwave reflective boundaries corresponding to a shape selected from elliptical patches and apertures, said boundaries providing guidance of microwaves leading to specific interference effects by interaction with the microwave heatable load, with dielectric materials when adjacent thereto, and with dielectric components of a microwave cavity or oven when the said active element is located beneath said load and when the load and element are supported thereby, said microwave reflective boundaries being formed by variation of constitutive parameters across the boundaries of the active element to provide contiguous regions with differing constitutive parameters constants, differing dielectric constants, differing magnetic permeabilities, and differing conductivities between the regions, and said interference effects being selected from constructive interference to provide resonant intensification of the microwave fields for intensification of microwave heating of the load, and from destructive interference to provide anti-resonant reduction of the microwave field intensities for reduced microwave heating of the load, the said active element being shaped in the form of an elliptical patch or aperture of eccentricity e=(a.sup.2 -b.sup.2).sup.1/2 /a where e is the eccentricity, and where a and b are the lengths from the origin to the intercepts along the major and minor axes, respectively, and for resonance p=2√πq/ae where p is the transverse wave number, also determined by p=2 π√.di-elect cons..sub.eff /λ.sub.o, and q is a parameter related to eccentricity and calculated as set out herein, .di-elect cons. eff is the effective dielectric constant adjacent to the element, and λ o is the free space wavelength of the microwaves.

Claim 15

An active element capable of modifying the microwave heating of a microwave heatable load, said active element having microwave reflective boundaries corresponding to a shape selected from elliptical patches and apertures, said boundaries providing guidance of microwaves leading to specific interference effects by interaction with the microwave heatable load, with dielectric materials when adjacent thereto, and with dielectric components of a microwave cavity or oven when the said active element is located beneath said load and when the load and element are supported thereby, said microwave reflective boundaries being formed by variation of constitutive parameters across the boundaries of the active element to provide contiguous regions with differing constitutive parameters constants, differing dielectric constants, differing magnetic permeabilities, and differing conductivities between the regions, and said interference effects being selected from constructive interference to provide resonant intensification of the microwave fields for intensification of microwave heating of the load, and from destructive interference to provide anti-resonant reduction of the microwave field intensities for reduced microwave heating of the load, the said active element being shaped in the form of an elliptical patch or aperture of eccentricity e=(a.sup.2 -b.sup.2).sup.1/2 /a where e is the eccentricity, and where a and b are the lengths from the origin to the intercepts along the major and minor axes, respectively, and for resonance p=2√πq/ae where p is the transverse wave number, also determined by p=2 π√.di-elect cons..sub.eff /λ.sub.o, and q is a parameter related to eccentricity and calculated as set out herein, .di-elect cons. eff is the effective dielectric constant adjacent to the element, and λ o is the free space wavelength of the microwaves.

Claim 16

An active element capable of modifying the microwave heating of a microwave heatable load, said active element having microwave reflective boundaries corresponding to a shape selected from triangle patches and apertures, said boundaries providing guidance of microwaves leading to specific interference effects by interaction with the microwave heatable load, with dielectric materials when adjacent thereto, and with dielectric components of a microwave cavity or oven when the said active element is located beneath said load and when the load and element are supported thereby, said microwave reflective boundaries being formed by variation of constitutive parameters across the boundaries of the active element to provide contiguous regions with differing constitutive parameters selected from differing dielectric constants, differing magnetic permeabilities, and differing conductivities between the regions, and said interference effects being selected from constructive interference to provide resonant intensification of the microwave fields for intensification of microwave heating of the load, and from destructive interference to provide anti-resonant reduction of the microwave field intensities for reduced microwave heating of the load, the said active element being shaped in the form of an equilateral triangular patch or aperture, and for resonance p=4 π(m.sup.2 +mn+n.sup.2).sup.1/2 /3a where p is the transverse wave number, also determined by p=2 π√.di-elect cons..sub.eff /λ.sub.o, a is the length of a side of the element, m and n are mode orders, m being a positive integer or zero if n is non-zero, and n being a positive integer or zero if m is non-zero, .di-elect cons. 2 eff is the effective dielectric constant adjacent to the element, and λ o is the free space wavelength of the microwaves.

Claim 17

An active element capable of modifying the microwave heating of a microwave heatable load, said active element having microwave reflective boundaries corresponding to a shape selected from triangle patches and apertures, said boundaries providing guidance of microwaves leading to specific interference effects by interaction with the microwave heatable load, with dielectric materials when adjacent thereto, and with dielectric components of a microwave cavity or oven when the said active element is located beneath said load and when the load and element are supported thereby, said microwave reflective boundaries being formed by variation of constitutive parameters across the boundaries of the active element to provide contiguous regions with differing constitutive parameters selected from differing dielectric constants, differing magnetic permeabilities, and differing conductivities between the regions, and said interference effects being selected from constructive interference to provide resonant intensification of the microwave fields for intensification of microwave heating of the load, and from destructive interference to provide anti-resonant reduction of the microwave field intensities for reduced microwave heating of the load, the said active element being shaped in the form of an equilateral triangular patch or aperture, and for resonance p=4 π(m.sup.2 +mn+n.sup.2).sup.1/2 /3a where p is the transverse wave number, also determined by p=2 π√.di-elect cons..sub.eff /λ.sub.o, a is the length of a side of the element, m and n are mode orders, m being a positive integer or zero if n is non-zero, and n being a positive integer or zero if m is non-zero, .di-elect cons. 2 eff is the effective dielectric constant adjacent to the element, and λ o is the free space wavelength of the microwaves.

Claim 18

An active element capable of modifying the microwave heating of a microwave heatable load, said active element having microwave reflective boundaries corresponding to a shape selected from hexagonal patches and apertures, said boundaries providing guidance of microwaves leading to specific interference effects by interaction with the microwave heatable load, with dielectric materials when adjacent thereto, and with dielectric components of a microwave cavity or oven when the said active element is located beneath said load and when the load and element are supported thereby, said microwave reflective boundaries being formed by variation of constitutive parameters across the boundaries of the active element to provide contiguous regions with differing constitutive parameters selected from differing dielectric constants, differing magnetic permeabilities, and differing conductivities between the regions, and said interference effects being selected from constructive interference to provide resonant intensification of the microwave fields for intensification of microwave heating of the load, and from destructive interference to provide anti-resonant reduction of the microwave field intensities for reduced microwave heating of the load, the said active element being shaped in the form of an hexagonal patch or aperture, and for resonance, generally, p=j'.sub.n,m /a(3√3/2/2 π).sup.1/2 where p is the transverse wave number, also determined by p=2 π√.di-elect cons..sub.eff /λ.sub.o, a is the length of a side of the element, m and n are mode orders, m being a positive integer or zero if n is non-zero, and n being a positive integer or zero if m is non-zero, .di-elect cons. eff is the effective dielectric constant adjacent to the element, and λ o is the free space wavelength of the microwaves.

Claim 19

An active element capable of modifying the microwave heating of a microwave heatable load, said active element having microwave reflective boundaries corresponding to a shape selected from hexagonal patches and apertures, said boundaries providing guidance of microwaves leading to specific interference effects by interaction with the microwave heatable load, with dielectric materials when adjacent thereto, and with dielectric components of a microwave cavity or oven when the said active element is located beneath said load and when the load and element are supported thereby, said microwave reflective boundaries being formed by variation of constitutive parameters across the boundaries of the active element to provide contiguous regions with differing constitutive parameters selected from differing dielectric constants, differing magnetic permeabilities, and differing conductivities between the regions, and said interference effects being selected from constructive interference to provide resonant intensification of the microwave fields for intensification of microwave heating of the load, and from destructive interference to provide anti-resonant reduction of the microwave field intensities for reduced microwave heating of the load, the said active element being shaped in the form of an hexagonal patch or aperture, and for resonance, generally, p=j'.sub.n,m /a(3√3/2/2 π).sup.1/2 where p is the transverse wave number, also determined by p=2 π√.di-elect cons..sub.eff /λ.sub.o, a is the length of a side of the element, m and n are mode orders, m being a positive integer or zero if n is non-zero, and n being a positive integer or zero if m is non-zero, .di-elect cons. eff is the effective dielectric constant adjacent to the element, and λ o is the free space wavelength of the microwaves.