Abstract: An electromagnetic wave absorber is provided with a first dielectric material layer (90, 200, 220) having two surfaces, a wave reflection layer (91, 201, 221) laminated on the one surface of the first dielectric material layer, a first resistive layer (92, 202, 222) laminated on the other, opposite, surface of the first dielectric material layer (90, 200, 220), and a second dielectric material layer (95, 205, 225) disposed proximate to the first resistive layer (92, 202, 222) leaving an air space, (94, 204, 224) having a thickness sufficient to determine adjust absorption characteristics for polarized waves, between the second dielectric material layer and the first resistive layer.

Abstract: An electromagnetic wave absorber has a pair of electromagnetic wave absorbing plates (10,11) made of ohmic resistance loss material with top portions (10a,11a) and bottom portions (10b,11b), and a common bottom support member (12) for supporting the bottom portions (10b,11b) of the plates (10,11). In assembled state, the top portions (10a,11a) of the plates (10,11) are fixed with each other and the bottom portions (10b,11b) of the plates (10,11) are fixed by the bottom support member (12) so that the plates (10,11) form an wedge shape.

Abstract: A flat wave absorber having a conductive plate, a dielectric plate on the conductive plate, and, a ferrite plate on said dielectric plate, provides a wide operational frequency range from 30 MHz to 1 GHz with excellent attenuation characteristics, and an anechoic chamber mounting said wave absorber on inside surface of the chamber is provided. Thickness of said dielectric plate is less than 25 mm, the thickness of said ferrite plate is less than 7.5 mm, and real part of complex impedance of said ferrite plate on the conductive plate is less than 1.0 and close to 1.0. Said ferrite plate is attached to said dielectric plate in the form of tiles.

Abstract: A parabolic antenna for SHF band having a primary feeder and a reflector is improved by using a backfire helical antenna as a primary feeder, which is fed by using a coaxial cable. The backfire helical antenna has a matching disc coupled with an outer conductor of the coaxial cable feeder, and a coil, one end of which is coupled with an inner conductor of said coaxial cable. The other end of the coil is free standing. The coil is positioned so that the axis of the coil coincides with the axis of the reflector, and the feed end of the coil locates nearer to the reflector than the free standing end of the coil. The present antenna is useful in particular for a receiving antenna for a direct satellite broadcasting.

Abstract: A microwave absorber device for a microwave heater having a chamber for cooking with an opening, and a door for closing the opening with a small gap which is a leakage path between the door and the wall of the chamber. The door is provided with a choke cavity at the peripheral portions of the same, the choke cavity having an approximate 1/4 wavelength of length, and an entrance facing the leakage path. The choke cavity is provided with wave absorber which includes ferrite, and/or carbon, at an edge of the entrance or an edge of the cavity. The wave absorber closes also the leakage path. The entrance itself is sealed by dielectric material.

Abstract: An electromagnetic shielding material for absorbing electromagnetic energy has been found. The shielding material is flexible and has a thin conductive core with a composite ferrite material deposited around the core. The composite ferrite material is a mixture of ferrite powder and a binder for binding the powder. The conductive core may be formed in the shape of a flat sheet or an elongated textile shape. The binder may be a high molecular compound like plastic. When the core is in a textile shape, the textile covered with the composite ferrite material is woven into a cloth which is sufficiently flexible to form around any desired shape.

Abstract: A microwave absorber device for a microwave heater having a main body with an opening and a door for closing said opening with a leakage path between the door and the main body. The absorber device has a choke cavity along a leakage path of the microwave energy between the main body and the door, said choke cavity having an approximate 1/4 wavelength of length, and an entrance facing said leakage path for accepting microwave energy. Said entrance of the choke cavity is closed by a cover plate made of ferro-magnetic material, which is a mixture of ferrite and gum. Preferably, an additional microwave absorber made of ferro-magnetic material which is integral with said cover plate is provided next to the choke cavity. Preferably, the dielectric constant of the material of the cover plate is less than 15. Still, preferably, the ratio of the imaginary part of the complex permeability to the real part of the same of the cover plate material is larger than 0.5.

Abstract: A composite ferrite cloth having ferro-magnetic property weaved with composite ferrite textile has been found. The composite ferrite textile is the mixture of ferrite powder and the binder for coupling the same. The binder may be a high molecule compound like plastics, or glass with low melting point. The composite textile may be produced either by slicing a composite ferrite sheet attached on a plastics substrate, depositing composite ferrite paint around a core textile similar to the producing process of an electric wire, or just mixing ferrite powder with plastics or glass. The ferrite cloth which is weaved with composite ferrite textile is flexible and has many fields of application.

Abstract: The present invention relates to an electromagnetic interference shielding material used for shielding radios and the like from electromagnetic waves emitted from a computer or the like. In the prior art, a zinc flame-sprayed shielding material is applied on the housing of a computer or the like to shield it from electromagnetic waves.The present invention provides an electromagnetic interference shielding material having an improved durability and shield effectiveness (SE) and comprising a ferromagnetic amorphous alloy having a conductivity of 10.sup.2 .OMEGA..sup.-1 .multidot.cm.sup.-1 or more and a permeability of 100 or more at 1 kHz.

Abstract: A popped corn making apparatus used in a microwave oven comprises a bowl having an opening at the upper part and a narrow closed bottom and a substantially conical shape; and a resonator placed at the bottom of said bowl. The electric field resulted by resonance of said resonator under an application of microwave, is applied to grains of corn contained in said bowl to produce a popped corn.It is possible to use a lumped element resonator comprising a one turn coil having a ring shape having an opening which is placed at the bottom of said bowl and which is formed by an inductance provided by said coil and a capacitance provided by said bowl and said grains of corn.

Abstract: An attenuator for use in filtering high-frequency waves propagated in a transmission line, comprising ferrite beads having a conductor passed therethrough which are enclosed firmly within a mixture having powder of ferrimagnetic material dispersed in an organic high polymer.

Abstract: Electromagnetic wave-absorbing wall comprising ferrimagnetic plates arranged at some intervals in the direction of the electric field of the electromagnetic wave said ferrimagnetic plates being plates of ferrite having the following general formula:MFe.sub.2 O.sub.4wherein M is a bivalent metal such as Mn, Ni, Co, Mg, Cu, Zn and Cd, or plates of a mixture of ferrite powders or carbonyl iron with organic high molecular weight compounds, and said plates having a specified thickness according to the interval.

Abstract: Coatings (or coat) for preventing reflection of electromagnetic wave on iron structures and coating material for use in forming said coatings, said coatings comprising ferrite powders and iron powders dispersed in organic high molecular weight compounds and said coating material comprising a dispersion of ferrite powders and iron powders contained in a solution of organic high molecular weight compounds dissolved in organic solvents.

Abstract: A vessel (ceramic cooking utensil) for use in heating food comprising a sintered body obtained by firing a mixture of ferrite powders and spodumene or petalite powders.

Abstract: A microwave heating oven has a seal located in the path formed by a gap between the oven body and the oven door for preventing microwave leakage. The seal may comprise several seals, and includes a microwave absorber as one of the seals. The microwave absorber consists of a mixture of a powder of magnetic material and an organic high molecular weight compound. The length of the microwave absorber in the direction of propagation of microwave in the path of microwave leakage is an integral multiple of about 1/2.lambda., wherein .lambda. is a wavelength of the microwave in the microwave absorber. Absorption is improved by setting the absorber in a recess in the wall or door of the oven, or by surrounding the absorber by a metal layer except on the surface thereof parallel to the direction of propagation and facing the gap.

Abstract: Microwave absorber comprising a mixture of ferrite powder having particle size of less than 1.65 mm and an organic high molecular weight compound.