GB1561685A

GB1561685A - Modularmounting apparatus for substrates bearingplanar circuits

Info

Publication number: GB1561685A
Application number: GB4249976A
Authority: GB
Original assignee: Tektronix Inc
Current assignee: Tektronix Inc
Priority date: 1975-11-20
Filing date: 1976-10-13
Publication date: 1980-02-27
Also published as: DE2652082A1; CA1062359A; JPS5264203A; NL7611831A; FR2352471B1; JPS5642159B2; FR2352471A1

Description

(54) MODULAR MOUNTING APPARATUS FOR SUBSTRATES BEARING PLANAR CIRCUITS (71) We, TEKTRONIX, INC., of 14150 South West Karl Braun Drive, Tektronix Industrial Park, near Beaverton, Oregon 97077, United States of America, a corporation organized and existing under the laws of the State of Oregon, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: Heretofore prior art packaging schemes for utilizing substrates bearing planar circuits and operating at microwave frequencies have involved the installation of such substrates into a reversible protrusion box or cavity of a milled out material using a paste down method such as conductive glue, epoxy sheet or indium solder. These methods work, but it is very difficult or in some instances impossible to repair or replace the substrates.

Other such prior art utilizes press down retainers, some of which include an embossed or quilted foil on the metallised side of the substrate, to install the substrates into a box or cavity. The pressdown method is satisfactory where small substrates are employed but is unsatisfactory when large substrates are used and will, environmentally speaking, deteriorate in time.

According to the present invention there is provided a modular package in which substrates containing planar circuits on at least the upper surface thereof and ground circuits on the bottom thereof, and modular package comprising housing means having side walls and a bottom defining a channelshaped configuration and also having a predetermined variable length; a cover member removably mounted on said housing means: end plates removably mounted in the ends of said housing means, said end plates containing access means for providing electrical connection to the planar circuits and the graound circuits; elastomeric conduction means in engagement with said bottom and extending substantially along the length thereof, said elastomeric conduction means being in electrical engagement with the ground circuits; removable substrate securing means extending between said housing means and the substrates urging the ground circuits into electrical connection with said elastomeric conduction means; and means sealing said substrates so as to be free from interfering signals.

Signal and power interconnections are made by means of parallel gap welding a thin gold ribbon to the coaxial cable to other substrates, or to a center conductor of terminals that are secured to the housing. The assembly is closed by means of either a mesh strip or conductive elastomer seal and a lid carrying suitable absorber pads where needed and then fastened to the housing.

The present invention will be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an exploded view of an apparatus according to the present invention; Figure 2 is a cross-sectioned view of the embodiment of Figure 1 with the components inserted; and Figure 3 is a partial view of a second apparatus according to the present invention.

Referring to the drawings, and in particular to Figure 1, there is shown in exploded view, a modular mounting apparatus for substrates bearing planar circuits according to the present invention. A nonreversible housing means 10, cut to a desired length depending upon the number of planar circuit bearing substrates required, is milled in a channel shaped configuration from a suitable material such as aluminum. The hous ing means is drilled and tapped to provide a plurality of attachment means 11, 12 and access ports 13. A groove 14 is disposed in and traverses. along both sides of the housing means and is provided for receiving a means for sealing the apparatus which will be described elsewhere in this specification.

A conductive elastomeric material 16 is next provided for disposal into a portion A of the channel shaped housing means 10.

The elastomeric material is preferably silver powdered silicone rubber having a low durometer rating so that it ise easily formed. The elastomeric material 16 provides a cushion and grounding support for the substrates to be hereinafter discussed, as well as for conduction of heat from the substrates for dissipation in the housing.

Also disposed in the A portion of the channel shaped housing means 10 are the substrates 18. These substrates are removably disposed in the housing means by securing means 20, which are retainer clips with integral cantilever tooth spring end means and secured by conventional screw means 22 threaded into attachment means 12 in the area B of the channelled housing means 10. These substrates 18 are preferably ceramic and have a metallised underside (not shown) for well known reasons. Additionally, these substrates 18 could be, say, an etched circuit board. Although not shown, these substrates 18 have planar circuitry thereon such as amplifiers, or oscillators.

The drawing shows 6 such substrates of various lengths adjacent one another and are shown by way of illustration only. Once the substrates 18 are disposed and secured to the housing means 10, the elastomeric material 16 provides the ground support to the ground or ground plane (the bottom of the housing means).

Next provided are a pair of end plates 24 milled from a suitable material, preferably zinc. These end plates 24 are placed adjacent the outer two substrates and are provided with signal conductors 28 in communication with the planar circuits, i.e., electrical connections. These end plates 24 are removably secured and selectively positioned in and along the housing means in the portions A and B by conventional screws 23 threaded into the attachment means 12 in the portion B. They also include a groove 26, similar to the groove 14, for receiving the means for sealing the apparatus. The signal conductors 28 provide for an input signal to the planar circuits on the substrates and for taking an output signal from the apparatus such as conventional BNC or UHF type connector systems having an insulated center conductor and a grounded outer conductor.

A seal 30, which is an absorber for radio frequency interference, is a woven mesh but can be a conductive elastomeric material for moisture considerations, is next provided for disposal into the groove 14 and the groove 26. Once installed, this seal completely surrounds the channel shaped housing means in the area or portion generally denoted C and extends slightly above the upper surface of the housing means 10. Once the seal 30 has been installed, a removable cover 32 is disposed along and over the channel shaped housing means 10 and the end plates 24 and removably secured thereto by further conventional screws 34 threaded into attachment means 11 in portion C of the housing means.

As can be discerned from the drawing of Figure 1, the apparatus may also include an additional member 36 defining a mode suppressor and is preferably an epoxy iron powder loaded lossy dielectric or similar member for absorbing both radio frequency energy and electromomgnetic energy. This member 36 is secured to cover member 32.

For example, assume that the substrate marked X included a planar circuit such as an oscillator operating in the microwave frequency range. Member 36 would be secured to cover member 32 directly above substrate X so that when cover member 32 is secured to the housing means 10 the absorber would prevent radiation therefrom.

Member 36 in the preferred embodiment is secured to the cover with an epoxy adhesive.

Also shown in Figure 1 are a plurality of additional lead throughs 38 for disposal into access ports 13. Additional signal, power, etc. connections may be made to the planar circuits by parallel gap welding a thin gold ribbon to the circuit leads. These additional lead-throughs could be, for example, BNC or UIIF connectors or feedthrough capacitors, i.e., filters.

Referring now to Figure 2, there is shown a cross sectional view of the apparatus shown in Figure 1, taken along the line 22 thereof. This drawing includes the various components disposed into the housing means 10. As was previously stated, the elastomeric material 16 is disposed into the portion A of the channel shaped housing means and the substrate 18 disposed on the elastomeric material. This figure shows the metallized underside 50 of the substrate 18 as previously stated. As can be discerned from this drawing, the total thickness of the elastomeric material 16, and substrate 18 extends above the A portion of the channel shaped housing means; this enables the spring end means of the securing means 20 to provide sufficient pressure on the combined units to securely hold them in place. Also shown in this drawing is a gold ribbon 52 which is welded to the lead 54 on the substrate 18 for providing electrical connection to the substrate from lead throughs 38. It should be emphasized that the lead 54 could be a transmission line, or a circuit component.

Also shown in the drawing is the inside portion of the means 24 ofr providing input signals to or taking output signals from the apparatus which comprises an insulative portion 56 and an inner conductive portion 58 which is soldered to another unit 60 which, like 54, is part of the planar circuit.

Referring now to Figure 3, there is shown a partial view of another embodiment of the apparatus according to the present invention.

This embodiment includes the housing means 10, a removable cover 32, sealing means 30, end plates 24, substrate 18, securing means 20 and the various screw means.

Additionally, there is shown an isolating means 61 which is removably received in the channel shaped housing means. The isolating means is similar to the end plates 24; the difference is, however, that the isolation means provides no means for providing input signals or means for taking output signals from the apparatus. The isolating means 61 is removably received in the housing and secured thereto by the securing means 62 threaded into the attachment means 11 (not shown). The isolating means 61 is generally used between two adjacent substrates. Also shown in the Figure 3 embodi ment is a side plate 65. Side plate 65 enables signal inputs and outputs from the side of the housing means, rather than the ends of the housing means. Side accesses, such as the plate 65, enable, say, the end plates 24 to be replaced by an isolating means 61, whenever desired. A still further type of additional lead-through are units 66, 67 comprising a bushing or sleeve and insert.

As has been previously stated, the sub strates are in communication with the bottom portion of the channel shaped housing means via the elastomeric material to pro vide a cushion and a ground (electrically).

Additionally, conductive portion of the lead-throughs such as the gold ribbons are in ungrounded (electrically) communication with the planar circuits. This, therefore provides for signal conduction via trans mission means which have a grounded outer conductor and conductive inner conductor.

While there has been shown and de scribed the preferred embodiments of the present invention, it will be apparent to thos skilled in the art that many changes and modifications may be made without departing from the invention in its broader aspects. For example, it is well known that both sides of the substrates may be utilized i.e., bear planar circuits. To utilize such a substrate, the elastomeric material is simply perforated where contact is not desired leaving an air gap between the planar circuit and the bottom of the channel shaped housing means. Therefore, the appended claims are intended to cover all such changes and modifications that fall within the scope of the invention.

WHAT WE CLAIM IS:- 1. A modular package in which substrates containing planar circuits on at least the upper surface thereof and ground circuits on the bottom thereof, the modular package comprising: housing means having side walls and a bottom defining a channel-shaped configuration and also having a predetermined variable length; a cover member removably mounted on said housing means; end plates removably mounted in the ends of said housing means, said end plates containing access means for providing electrical connection to the planar circuits and the ground circuits; elastomeric conduction means in engagement with said bottom and extending substantially along the length thereof, said elastomeric conduction means being in electrical engagement with the ground circuits; removable substrate securing means extending between said housing means and the substrates urging the ground circuits into electrical connection with said elastomeric conduction means; and means sealing said substrates so as to be free from interfering signals.

2. The apparatus according to claim 1 further comprising removable isolation means which may be located between said side walls of said housing means for electrically and physically isolating one substrate from another.

3. The apparatus according to claim 1 further comprising access means disposed on the lateral sides formed by said housing means.

4. A modular package in which planar circuits are mounted, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

for providing electrical connection to the substrate from lead throughs 38. It should be emphasized that the lead 54 could be a transmission line, or a circuit component.

Also shown in the drawing is the inside portion of the means 24 ofr providing input signals to or taking output signals from the apparatus which comprises an insulative portion 56 and an inner conductive portion 58 which is soldered to another unit 60 which, like 54, is part of the planar circuit.

Referring now to Figure 3, there is shown a partial view of another embodiment of the apparatus according to the present invention.

This embodiment includes the housing means 10, a removable cover 32, sealing means 30, end plates 24, substrate 18, securing means 20 and the various screw means.

Additionally, there is shown an isolating means 61 which is removably received in the channel shaped housing means. The isolating means is similar to the end plates 24; the difference is, however, that the isolation means provides no means for providing input signals or means for taking output signals from the apparatus. The isolating means 61 is removably received in the housing and secured thereto by the securing means 62 threaded into the attachment means

11 (not shown). The isolating means 61 is generally used between two adjacent substrates. Also shown in the Figure 3 embodi ment is a side plate 65. Side plate 65 enables signal inputs and outputs from the side of the housing means, rather than the ends of the housing means. Side accesses, such as the plate 65, enable, say, the end plates 24 to be replaced by an isolating means 61, whenever desired. A still further type of additional lead-through are units 66, 67 comprising a bushing or sleeve and insert.

As has been previously stated, the sub strates are in communication with the bottom portion of the channel shaped housing means via the elastomeric material to pro vide a cushion and a ground (electrically).

Additionally, conductive portion of the lead-throughs such as the gold ribbons are in ungrounded (electrically) communication with the planar circuits. This, therefore provides for signal conduction via trans mission means which have a grounded outer conductor and conductive inner conductor.

While there has been shown and de scribed the preferred embodiments of the present invention, it will be apparent to thos skilled in the art that many changes and modifications may be made without departing from the invention in its broader aspects. For example, it is well known that both sides of the substrates may be utilized i.e., bear planar circuits. To utilize such a substrate, the elastomeric material is simply perforated where contact is not desired leaving an air gap between the planar circuit and the bottom of the channel shaped housing means. Therefore, the appended claims are intended to cover all such changes and modifications that fall within the scope of the invention.

WHAT WE CLAIM IS:- 1. A modular package in which substrates containing planar circuits on at least the upper surface thereof and ground circuits on the bottom thereof, the modular package comprising: housing means having side walls and a bottom defining a channel-shaped configuration and also having a predetermined variable length; a cover member removably mounted on said housing means; end plates removably mounted in the ends of said housing means, said end plates containing access means for providing electrical connection to the planar circuits and the ground circuits; elastomeric conduction means in engagement with said bottom and extending substantially along the length thereof, said elastomeric conduction means being in electrical engagement with the ground circuits; removable substrate securing means extending between said housing means and the substrates urging the ground circuits into electrical connection with said elastomeric conduction means; and means sealing said substrates so as to be free from interfering signals.
2. The apparatus according to claim 1 further comprising removable isolation means which may be located between said side walls of said housing means for electrically and physically isolating one substrate from another.
3. The apparatus according to claim 1 further comprising access means disposed on the lateral sides formed by said housing means.
4. A modular package in which planar circuits are mounted, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.