JP2004039764A - Manufacturing method of high frequency transmitting / receiving device - Google Patents

Abstract

An interference between electromagnetic waves inside and outside a housing, that is, an interference between circuit elements inside a housing or between a circuit element inside a housing and an electromagnetic wave outside a housing without hindering mass production and cost reduction of the device. Provided is a high-frequency communication device that reduces electromagnetic coupling.
In a communication device having a housing in which a high-frequency circuit element is mounted, a periodic structure having a projection periodically formed on at least a part of a wall forming the housing is provided by bonding, caulking, or the like. The periodic structure was formed by covering the surface of an organic or inorganic material with metal by plating and vapor deposition.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a high-frequency transmitting / receiving device suitable for a microwave signal transmitting / receiving device, particularly a vehicle radar measuring device.
[0002]
[Prior art]
Automobile radars using millimeter waves and high-frequency wireless communication devices and radio terminals using radio waves in the frequency band of 300 MHz or more are required to reduce the size and cost of the devices and to increase the number of functions of circuit elements used. A single multifunctional semiconductor device or a semiconductor integrated circuit (IC), a package on which they are mounted, or a plurality of ICs and a high-frequency circuit device including a filter function or the like which are interconnected in a single housing. Implement. As an example of a communication device having such a structure, there is a transmission / reception device used for an automotive radar described in the IEICE General Conference C-2-121 "60 GHz band millimeter wave radar unit". This device has a structure in which a millimeter wave (60 GHz band) transmitting / receiving circuit is housed in a housing surrounded by a plane surface.
[0003]
[Problems to be solved by the invention]
When a large number of functional elements are housed in a single housing structure, the size of the housing is constant, and the larger the number of functional elements, the shorter the physical distance between the functional elements or the smaller the size of the housing. The magnitude is larger than half the free space wavelength of the signal frequency (for example, about 1.95 mm 2 at 77 GHz). In any case, the radio wave energy of the signal frequency radiated into the housing from one point such as an IC constituting the functional device in the housing easily propagates in the housing and is coupled to the functional device in the same housing. Causes various functional disorders. For example, in transmission / reception transceivers and transmission / reception modules for millimeter-wave automobile radars, some of the signals radiated from the transmission function element into the housing are coupled to the reception function element, thereby causing problems such as saturation of the receiver and increase in reception noise. Cause
[0004]
In order to solve these problems, especially the problem of interference in the housing, conventional communication devices are required to subdivide the housing structure and divide it into multiple small rooms with metal bulkheads, or to emit unnecessary radiation along the original signal path. Has been provided with a metal structure that locally forms a cut-off waveguide structure. These prior arts require a complicated metal structure for the structure of the housing and a plurality of divisions of the high-frequency substrate of the passive circuit, and furthermore, a semiconductor IC and a passive circuit component for the division of the structure and the substrate. This makes mounting more difficult, and hinders mass production and cost reduction of communication devices.
[0005]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for interfering electromagnetic waves inside and outside a casing, that is, between circuit elements inside a casing or between electromagnetic elements inside a casing and electromagnetic waves outside the casing without hindering mass production and cost reduction of the apparatus. It is an object of the present invention to provide a high-frequency communication device that reduces unreasonable electromagnetic coupling.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a communication device having a high-frequency circuit element and an antenna operating with a signal in a high-frequency band such as a microwave or a millimeter wave, and having at least the housing in which the high-frequency circuit element is mounted, A periodic structure in which protrusions are periodically formed on at least a part of a wall constituting the housing is provided by bonding, caulking, or the like, and the periodic structure covers the surface of an organic or inorganic material with metal by plating and vapor deposition. Was. The above-mentioned periodic structure is configured as a filter in which a frequency band including a frequency of an unnecessary radiated radio wave in which a housing portion including the periodic structure becomes a problem in the housing is a non-propagating frequency band.
[0007]
ADVANTAGE OF THE INVENTION According to the high frequency communication apparatus of this invention, the radiation energy from the unnecessary radio wave radiation source in a housing | casing can be locally confined and interference with others can be prevented. In addition, interference can be suppressed by attenuating radiant energy from an external unnecessary radio wave radiation source. When there are a plurality of frequencies of interest in the housing, a plurality of interference problems can be dealt with by adding different periodic structures to each of the necessary parts in the housing. Furthermore, if these periodic structures are attached to the ceiling of the housing structure, if this ceiling is designed as a lid for the housing, the other housing parts will have a much simpler shape (for example, a rectangular parallelepiped) much larger than the wavelength. This makes it possible to use a single high-frequency substrate for the high-frequency substrate, which makes it easy to mount a semiconductor or the like in the housing and realizes a module including the housing at low cost.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a high-frequency transmitting / receiving apparatus and a method of manufacturing the same according to the present invention will be described in detail with reference to the illustrated embodiments.
[0009]
FIG. 1 shows an example of application of the system of the present invention, in which an inter-vehicle distance and a relative speed with respect to a preceding vehicle 3 in a host vehicle 2 equipped with a high-frequency transmitting / receiving device 1 are measured.
[0010]
FIG. 2 is a sectional view of a microwave or millimeter wave transmitting / receiving apparatus which is an embodiment of the high-frequency transmitting / receiving apparatus according to the present invention. A semiconductor IC 10 such as a transmission / reception MMIC and a planar circuit board 9 connecting the semiconductor ICs 10 are mounted on a surface of a metal base plate 7 which is a bottom of the housing to constitute a transmission / reception circuit. And 11b are connected to the antenna 8. The metal lid 6 constitutes the ceiling of the housing, and the filter 5 having the rectangular projection 13 periodically provided on the ceiling facing the inside of the housing of the lid 6 is adhered by the adhesive 12. Have been.
[0011]
FIG. 3 is a cross-sectional view showing a structure in which the filter 5 is crimped and fixed to a ceiling part facing the inside of the housing of the lid 6 in FIG. 2 with a metal member 14 for crimping instead of bonding. .
[0012]
FIG. 4 is a partially enlarged cross-sectional view of the filter 5. The filter 5 is obtained by depositing films 5-1 and 5-2 on a formed body formed by machining and pressing with an organic or inorganic material. The composition is (1) nickel and gold, (2) nickel and silver,
(3) One of the copper groups is deposited in the order described. The film deposition method is based on plating and vapor deposition.
[0013]
The ceiling covered with the metal having periodic irregularities configured in this manner, together with the metal surface on which the transmitting and receiving circuit is mounted, is resistant to microwaves or millimeter waves that are going to propagate in the space in the housing between them. A filter structure in which the wave impedance is periodically changed is configured to exhibit a characteristic having a propagating frequency band and a non-propagating frequency band alternately as a function of frequency. Therefore, for example, by designing the present filter structure so that the operating frequency band of the transmitting and receiving circuit falls within the non-propagating frequency band, unnecessary radiation from the transmitting side of the transmitting and receiving circuit to the inside of the housing is prevented from reaching the receiving side, and transmission and reception interference is prevented. Can be reduced.
[0014]
FIG. 5 is a plan view of the filter 5 in which the casing ceiling shown in FIG. 2 is viewed from the inside of the casing. The protrusions 13 are two-dimensionally arranged on a substantially entire surface at a constant period.
[0015]
FIGS. 6 and 7 are enlarged views of a part B of FIG. 2 and a part C of FIG. 5, respectively, for explaining the operation principle of the main part of the present invention. For simplicity, FIG. 6 shows only the base plate 7, the filter 5, the adhesive 12, and the lid 6 excluding the semiconductor IC 10 and the antenna 8.
[0016]
The protrusion 13 shown in FIGS. 6 and 7 is a rectangular parallelepiped having widths W1 and W2 and a height D, respectively. As shown in FIG. 7, the projections 13 have a horizontal gap G1 and a vertical gap G2, and are two-dimensionally arranged with a horizontal period P1 and a vertical period P2. In FIG. 6, the distance H between the lid 6 and the base plate 7 is defined as H when the free space wavelength with respect to the design frequency is λ in order to prevent the electromagnetic field higher-order mode from standing in the H direction and maintain the high characteristics of the filter structure. It is desirable to satisfy <λ / 2.
[0017]
FIG. 8 shows a configuration in which the projection 13 of the filter 5 is a cylindrical body, and is arranged in the same manner as in FIGS. 6 and 7.
[0018]
FIG. 9 shows that when the function of operating at three different main frequencies is present inside the housing, the protrusions 13 of the filter 5 correspond to the periodic structures 13-2, 13-3 and 13-4 in the respective regions. , The interference between the functions is effectively reduced. That is, assuming that the period P of the periodic structure at each of the three locations is a free space wavelength with respect to the design frequency at each location, the range is (2N + 1) λ / 5 ≦ P ≦ (2N + 1) 5λ / 9 ( Here, N is set to 0 or an integer.
[0019]
The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments. For example, the lid is cap-shaped, but the side wall may be provided separately, and the material may not be made of metal.
[0020]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the interference by unnecessary radiation electric wave energy in a housing | casing, EMC, EMI problem can be reduced significantly only by adding a simple periodic structure to a part of high frequency housing | casing structure, A high-frequency system can be realized at low cost without deteriorating its overall characteristics. Further, in most cases, it is possible to design the filter characteristics based on the periodic structure so as not to depend on reliable metal contact. Therefore, it is possible to reduce the variation in mass production and the change over time of the housing structure for a high-frequency transceiver such as a millimeter-wave automobile radar. Can be reduced.
[Brief description of the drawings]
FIG. 1 is a system application example of the present invention.
FIG. 2 is a sectional view showing an embodiment of a high-frequency circuit according to the present invention.
FIG. 3 is a sectional view showing a second embodiment of the high-frequency circuit according to the present invention.
FIG. 4 is an enlarged sectional view of a filter according to the present invention.
FIG. 5 is a plan view of the filter as viewed from the high frequency circuit side.
FIG. 6 is a partially enlarged sectional view of FIG. 2;
FIG. 7 is a partially enlarged sectional view of FIG. 5;
FIG. 8 is a plan view in which a projection shape of a filter is changed.
FIG. 9 is a plan view in which three types of filter protrusions are arranged.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... High frequency transmission / reception apparatus, 2 ... own vehicle, 3 ... preceding vehicle, 5 ... filter, 6 ... lid, 7 ... base plate, 8 ... antenna, 9 ... planar circuit board, 10 ... semiconductor IC, 11 ... coaxial line, 12 ... Adhesive, 13 protrusion, 14 member.

Claims (5)

A communication device having a high-frequency circuit and an antenna, wherein at least the high-frequency circuit is mounted inside a housing, and a periodic structure having a projection provided at least partially on a wall of the housing is adhered. A method for manufacturing a high-frequency transmitting / receiving device, characterized by being fixed by crimping, crimping, or the like. 2. The method according to claim 1, wherein the periodic structure has a surface of an organic or inorganic material covered with a metal film by plating and vapor deposition. The method according to claim 2, wherein the periodic structure is formed on an inner wall of the housing. In claim 1,
The metal film of the periodic structure is (1) nickel and gold, (2) nickel and silver,
(3) A method for manufacturing a high-frequency transmitting / receiving device, wherein any one of copper is included. In claim 1,
A method for manufacturing a high-frequency transmitting / receiving device, wherein the shape of the protrusion of the periodic structure is a cut square, a cut cylindrical, a press square, a press cylindrical, or a molded.

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