FI105314B - Radio frequency circuit board cover - Google Patents

Abstract

The present invention relates to a shielded electronic circuit for radio-frequency signals. The shielded electronic circuit for radio-frequency signals comprises, on a support (1), a cell (5) disposed above an earth plane (8) and covered with a metal cap (6). In addition, the support comprises a pattern feature (7) to which this cap is applied and a ring of holes (10) which are covered with an electrically conductive material connecting this pattern feature to the earth plane. The cell (5) comprises a power module (16) and the support (1) comprises an exchange surface (17), to which this power module is attached, which extends as far as the pattern feature (7). <IMAGE>

Description

105314

This invention relates to a cover for 5 circuits for handling radio frequency signals.

Electrical circuits for processing radio frequency signals generally include a substrate, such as a printed circuit board or multilayer circuit board, with front interfaces and connected components. This substrate usually includes a ground surface placed on its rear surface or possibly an intermediate layer / in the case of a multilayer printed circuit board.

Where electromagnetic shielding is to be applied around such a circuit, it is known to use a metal housing with a cell formed by an inner part thereof. It is further known from DE-A-3 811 313 to use a surface pattern of a surface conductive material which surrounds the circuit modules and to which a metal sheath is attached.

The continuity of the shield through the substrate between the ground surface and the metal sheath is then secured by screws or welded metal spikes that connect the front surface and the ground surface. These screws and prongs are detrimental to the automation of the circuit assembly and the removal of the cover: ***: for repair and adjustment of the circuit.

30 U.S. Pat. No. 4,739,453, in turn, proposes to ensure continuity of protection by using a structure formed of metallized holes. However, if the circuit board includes a power module, the thermal energy produced by such a module must be removed. A cooler for this purpose is known. The radiator must be mechanically secured to the circuit, which also prevents

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It is thus an object of the invention to provide a radio frequency circuit cap which acts through the substrate and allows the power module to be cooled, and which does not have the aforementioned disadvantages.

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The radio frequency circuit cap according to the invention consists of a substrate having an active surface and a back surface, the substrate having on the one hand a ground surface on its back or one intermediate layer of the substrate and on the other 10 a surface arrangement of the substrate a housing and a frame made of electrically conductive material lined with holes that connects the surface pattern 15 to the ground surface, characterized in that the active surface of the substrate has a heat exchange surface to which a power module is attached, this heat exchange surface being coated with extends, on the one hand, to one or more walls of a housing located in the immediate vicinity of the power module, which is part of the circuit arrangement power 20, on the other.

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M1 * The distance in the RF shield that • ·: * '25 separates the two consecutive holes in the substrate

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, is less than one-third of the wavelength of the signals processing the radio frequency circuit.

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In addition, the platform in the RF shield may: * · *; 30 may be a multilayer circuit board, the ground surface being formed on an intermediate layer of the multilayer circuit board.

The ground surface in the RF shield may also be located on a surface opposite to the circuit arrangement.

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Other objects and features of the invention will be more fully apparent from the following description of the embodiments thereof, which, however, are not intended to limit the invention in any way, and which are accomplished by reference to the accompanying drawings, in which:

Fig. 1 is a sectional view of a radio frequency circuit provided with a shield according to the invention;

Figure 2 is a plan view of this circuit; 10

Figure 3 is a sectional view of an alternative embodiment of a radio frequency circuit with a shield; and

Fig. 4 is a plan view of this alternative direct-lumen.

The same elements in the various figures are denoted by the same reference numerals.

The radio frequency circuit shown in section in Fig. 1 includes a substrate 1, such as a printed circuit board, multiplied ···. rosette board or ceramic substrate. The second surface of this substrate, which may be conveniently referred to herein as the active surface 2, is provided with components 3, and connectors (not shown) connecting the components to one another. circuit arrangement ··· 1 is covered with a metal sheath 6.

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In Fig. 2, the same circuit is shown viewed from above the active surface 30 and the sheath 6 removed. The substrate 1 includes an electrically conductive surface pattern 7 on which the mantle 6 is positioned. VED. Also included is a ground surface 8 below the active surface, the periphery of which substantially coincides with the contour of surface pattern 7.

35 ···. For example, the ground surface is placed on the back surface of the substrate 4 · f or on the inner layer of the multilayer PCB.

105314 Electrically conductive material 11 lined, e.g., metalized holes 10 connect the pattern surface 7 to the ground surface 8. The pattern 7 is provided with holes 10 along its entire length, providing complete electromagnetic shielding of the circuit arrangement 5.

The electrical circuit can be mounted in a metal housing. In this case, the housing 6 may be replaced by a cell 10 contained in the housing into which the circuit arrangement 5 is arranged to be located. Thus, the term diaper also refers to such technical solutions.

In the variant of the electrical circuit shown in Fig. 3, it is now 15 mounted in the housing 15. The above consideration also applies here, but the circuit arrangement 5 also includes a te-module 16. In Fig. 4, the circuit is viewed from the active surface side. The heat exchange surface 17, which is coated with a highly conductive material 20 and disposed on the active surface 2, extends from below the te-module to one or more walls of the housing 15. below this module, which are located in the immediate vicinity of this module. The heat exchanger surface is a pre-«« .. sign, a metallic plane surface. The heat energy generated by the power module 16 is thus supplied to the heat exchange surface 17, which again transfers it to the housing 15.

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··· ·. * * The contact between the pattern surface 7 and / or the heat exchange surface 17 on the one hand, and the casing 6 or housing 15, on the other, can be secured by a compression joint, particularly by using a spring-loaded material. In general, all types of known joints are suitable, in particular welding, gluing or screw mounting.

Without departing from the scope of the invention, the electrical circuitry may include: ***: a plurality of shielded circuit arrangements, whereby these circuitry * 4 · arrangements may be located on both sides of the substrate.

Claims (2)

A radio frequency circuit screen, this screen comprising a support (1) having an active side and a back side, the support comprising & one side a ground plane (8) located p4 its back side or on an inner layer of the substrate and, on the other hand, a cell of the circuit arranged on the active side of the substrate and covered by a metal cap (15), the substrate on its active side further comprising a sample (7) on which said cap is applied and a ring of heels (10) lined with an electrically conductive material connecting said specimen (7) to said ground plane (8), characterized in that the support on its active side comprises a heat exchange surface (17) to which is attached a power module (16) , wherein this heat exchange surface is covered by a material which has a good thermal conductivity and extends one side under the cell's power module (16) and on the other side under one or more of the walls (18) of the cover located in the immediate vicinity. r-20 of the power module. 1. Radiotaajuuspiirin suojus, jolloin tämä suojus muodostuu alustasta (1), jolla on aktiivipinta ja takapinta, jolloin alustaan kuuluu toisaalta maattopinta (8), joka 15 on sen takapinnalla metallicotelolla (15), jolloin alustalla on aktiivipinnallaan lisäksi pintakuvio (7), young pallel kotelo sijoitetaan ja sähköä johtavalla 20 materialilla vuoratuista rei'ista (10) muodostuva kehys, joka yhdistää pintakattion aktiivipinnalla on lämmönvaihtopinta (17), dinghy tehomoduuli (16) on kiinnitetty, jolloin tämä lämmönvaihtopinta on päällystetty materialilla, jolla on 25 hyvä lämmönjohtavuus ja joka ulottuu toisaalta piirijär- * jest - • · · V · lon yhden tai useamman s one (18) all. : ***: 30 2. Patenttivaatimuksen 1 mukainen suojus, tunnettu siitä, • · · ** pienempi kuin • M kolmasosa radiotaajuuspiirin käsittelemien signaalien aallonpituudesta.% «« efeciii «t« Il «« i «i 6 105314 Shielding according to claim 1, characterized in that the distance separating two successive heels (10) in said support (1) is less than one third of the path length of the signals processed by the radio frequency circuit. «IC f It · · · · · · · · · · · · ··· •» · • · e «· •» • · · · »· • · ·· · * M · • IM 'IM *« • «» • lii • · f • · • * · · * «