Uniden Corporation

Nippon Paint Compnay, Ltd.

Nippon Hoso' Kyokai

K. Laboratory Co., Ltd.

Yoshihiro Konishi

Hideki Fujiwara

Kenichi Konno

Hideo Hikuma

Mitsuyuki Oda

Masahito Asa

Koji Nakamura

Ikuo Awai

Kazuo Maeda

Kazunori Kanda

Yoshihiko Baba

Masato Morimoto

Shoichi Iida

Shoichiro Nomura

Haruaki Fujimoto

Masami Ohsaki

Yoshio Okuma

Norio Hoshino

Norihiko Yazawa

A housing for electronic apparatus which is effectively protected against electromagnetic wave leakage, the housing being equipped or lined, in an area of the conductive layer-carrying inside surface of the housing, the area adjoining, or is in the vicinity of, an opening of the housing, with a sheet molded, to a thickness of 70 to 300 .mu.m, from a magnetic material-containing resin composition comprising 7 to 60% by weight of a binder resin (a) and 40 to 93% by weight of a finely divided magnetic material (b) having a magnetic loss term, and a method of damping unwanted radiation of electromagnetic waves.

Housing for electronic apparatus and method of damping unwanted

A distributed constant type multiple-line circuit is described which comprises a dielectric block (60) having shield conductors (62,64) on its rear surface and all the peripheral side surfaces, a central conductor (1) extending in the block in the front-to-rear thickness direction at the central portion thereof, a first plurality of conductors (2-5) positioned around and parallel to the central conductor and inductively coupled therewith, and a second plurality of conductors (2'-5') positioned nearby and parallel to the first conductors and inductively coupled therewith, respectively. The length of the central conductor is equal to one quarter of the wavelength of the central frequency (f.sub.1) in a frequency band, and the rear end thereof is isolated with the shield conductor on the rear surface of the block. Each of the lengths of the first conductors is equal to one quarter of the wavelength of a predetermined frequency (f.sub.2 -f.sub.5) in the frequency band, and the rear ends thereof are shorted with the shield conductor on the rear surface of the block. Each of the lengths of the second conductors is equal to that of the corresponding one of said first conductors, and the rear ends thereof are isolated with the shield conductor on the rear surface of the block. An input signal (S.sub.IN) iS input to the front end of the central conductor, and signal components of frequencies (f.sub.2 -f.sub.5) are respectively output through the first conductors from the front ends of the second conductor.

Distributed constant type multiple-line circuit

As for an electric apparatus having a case formed of electro-magnetic wave passing-through material, in order to provide an electro-magnetic wave shielding structure being capable to effectively prevent the leakage therefrom of an electro-magnetic wave generated therein, an electro-magnetic wave reflecting layer, namely, a conductive layer is formed on an inner face of the case and further, on a surface of the conductive layer, a magnetically losing layer containing Mn--Mg--Zn group soft ferrite particles having 1 to 20 .mu.m average diameter by 70 to 90 weight % at a thickness exceeding 80 .mu.m is formed, so as to repeatedly absorb the inner generated undesired electro-magnetic wave therein through repeated reflection between the conductive layer and the absorbing layer.

Electronic apparatus case having an electro-magnetic wave shielding

To prevent variation of a transmission band characteristic which is caused by variation of operational conditions (e.g., temperature in the rectification feedback amplification) in a system with large extraband attenuation for sharply cutting off the transmission band in each channel of the communication system including plural narrow band channels allotted close to each other, rectification feedback is effected through through an adaptive filter. A band characteristic of the adaptive filter is varied in response to the variation of operational conditions including temperature, while data processing is rapidly effected through digital signal processing. Consequently, even if the communications in each channels are intermittently repeated, each time the communication is reopened, the desired transmission band characteristic can be instantly fixed, so as to prevent the disturbance of stable operation by adjudicating the interference through data correlation.

Rectification feedback high frequency circuit arrangement including an

To avoid deterioration of isolation between two distributed power outputs in higher and lower end portions of an available frequency region of a Wilkinson power distributor, plural stages of ferrite-loaded close-coupled parallel dual lines for providing a Wilkinson power distributor, an electric length of which lines is shortened within a range in which desired isolation can be obtained, are connected in cascade. As a result, two distributed power outputs having a constant phase difference with sufficient isolation throughout an extremely wide frequency range can be obtained.

Ultra-wide frequency range constant phase difference power distributor

To realize an element presenting a constant impedance throughout an extremely wide frequency range and a circuit supplying a high frequency signal having a constant phase throughout the same wide frequency range, a ferrite-loaded line element, a real part of a terminal complex impedance of which is substantially constant, is provided. A partial inclination of an imaginary part of the terminal complex impedance is compensated by providing a pure reactance element, in combination therewith As a result, in an extremely wide frequency range exceeding a natural magnetical resonant frequency, a ferrite-loaded constant impedance element and a constant phase circuit comprising this constant impedance element can be attained.

Ferrite loaded constant impedance element and a constant phase circuit

In a dielectric material block surrounded by a metal film at least one air hole is provided. Inner faces of the at least one air hole are partly applied with at least one metal film. The at least one air hole is provided for providing coupled distributed lines, which are mutually coupled by electric fields passing partly through the at least one air hole, so as to realize a dielectric band pass filter, which has a small-sized structure and attains high precision and non-alignment of resonant frequency.

Quasi-TEM mode dielectric filter

For sufficiently shielding an undesired electro-magnetic wave from penetrating into a communication apparatus, for instance, a car telephone through stray coupling, or leaks therefrom, an electronic circuit substrate and a case of the communication apparatus are formed of flat plates which consist of insulating material comprising magnetic material. One side surface of the flat plates are covered with conductive films. The communication apparatus itself is accommodated in the case and an electric power source connecting cable is wrapped by a similar arrangement, so as to remarkably reduce obstructions caused by undesired waves and other communications in comparison with the conventional arrangement.

Electro-magnetic wave shielding structure

To overcome conventional increase of insertion loss and conventional discrepancy of phase characteristic of an S/N enhancer provided for increasing S/N of an electro-magnetic wave to be converted into a magneto-static wave by utilizing saturation of magneto-static wave power propagating through a ferrite thin film, a novel operational principle is used, wherein a large variation of impedance of a strip line, provided for converting electro-magnetic waves into magneto-static waves in the vicinity of saturation of the magneto-static wave. The electro-magnetic wave reflected from the input terminal of the strip line is selectively derived as an output wave through a directional coupling device. As a result, particularly for an electro-magnetic wave applied with wide-band FM modulation, S/N can be remarkably increased without any increase of insertion loss or any influence of phase characteristic discrepancy.

S/M enhancer

In order to efficiently and steadily remove a frequency-fluctuating interference wave, for instance, a leakage wave of a household electronic oven, intermixed into a received wave for communication, adaptively to the frequency deviation and the frequency fluctuation of the interference wave, a rejection band component included in the received wave applied onto a circulator an output terminal of which is connected with a variable band rejection filter is reflected from the output terminal on which impedance mismatch is caused by zero-impedance presented by the rejection filter on the basis of absorption of input wave and applied to a detector through the circulator again, in response to a detection output of which a so-called mountaineering control is effected on the variable band rejection filter for shifting the rejection band, so as to maximize the detection output of the detector adaptively to the frequency deviation and the frequency fluctuation of the interference wave.

Frequency-fluctuating interference removed receiver

In order to efficiently and steadily remove a frequency-fluctuating interference wave, for instance, a leakage wave of a household electronic oven, intermixed into a received wave for communication, adaptively to the frequency deviation and the frequency fluctuation of the interference wave, a rejection band component included in the received wave applied onto a circulator, an output terminal of which is connected with a variable band rejection filter, is reflected from the output terminal on which impedance mismatch is caused by zero-impedance presented by the rejection filter on the basis of absorption of the input wave and applied to a detector through the circulator again, in response to a detection output of which a so-called peak-keeping control is effected on the variable band rejection filter for shifting the rejection band, so as to maximize the detection output of the detector adaptively to the frequency deviation and the frequency fluctuation of the interference wave.

For removing the variation of resonant frequency of the 1/4 .lambda.g coaxial resonator, which is caused by the external connection as a result of conventional capacitive coupling, a 1/4 .lambda.g line having both ends opened is coupled to the 1/4 .lambda.g resonant line having one end shorted through distributed inductive coupling, so as to provide a basic structure of the dielectric resonator of the invention, which can be arranged in usual various types of circuits such as filters, multiplexers and the like with excellent and stable performances.

Dielectric multi-line resonator including a coupling conductor line

For realizing a highly sensitive and favorably linear frequency modulator stably operating with a small-sized and readily manufactured arrangement, input and output strip electrodes are disposed in face on both ends of a ferri-magnetic film deposited on a magnetic substrate and applied with a DC magnetic field perpendicular thereto, a high frequency electro-magnetic wave being applied through the input electrode, so as to generate a magneto-static forward volume wave propagating through the magnetic film, the propagation phase of which is modulated in response to the intensity variation of the applied magnetic field modulated by a signal, so as to derive a frequency modulated electro-magnetic wave from the output electrode.

Ferri-magnetic film frequency modulator

A dielectric waveguide-type filter is fabricated by vapor depositing or coating all but one of the four sides extending in the axial direction of a six-sided dielectric block that is long in its axial direction lying perpendicular to its width and height with a conductive material and either leaving the fourth side surface open or forming it with a conductive pattern depending on whether the filter characteristics to be obtained are high-pass characteristics, band-pass characteristics or band-rejection characteristics, the conductive pattern, if formed, being formed in a configuration and distribution depending on the filter characteristics to be obtained. A pair of electrode patterns for electrical connection with an exterior circuit are provided by patterning of conductive material on the opposite axial end surfaces of the dielectric block or on the open surface at positions near the opposite axial end surfaces.

Dielectric waveguide-type filter

A compact resonant wave filter capable of selectively propagating an electromagnetic wave of a prescribed frequency with excellent band-pass wave filter characteristics comprises a TM mode resonator disposed perpendicularly to the direction of propagation of electromagnetic wave energy, a pair of TEM mode resonators disposed one on either side or said TM mode resonator in the direction of propagation of electromagnetic wave energy, and a pair of cutoff waveguides disposed one between said TEM mode resonator and each of said TM mode resonators to couple said TEM mode resonator with said TM mode resonators in evanescent mode.

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Sagamihara, Japan

Yoshihiro Konishi