WO1995009452A1 - Microwave circuit - Google Patents
Microwave circuit Download PDFInfo
- Publication number
- WO1995009452A1 WO1995009452A1 PCT/SE1994/000888 SE9400888W WO9509452A1 WO 1995009452 A1 WO1995009452 A1 WO 1995009452A1 SE 9400888 W SE9400888 W SE 9400888W WO 9509452 A1 WO9509452 A1 WO 9509452A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- microwave circuit
- matching
- ground plane
- pattern
- conductor
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/0213—Electrical arrangements not otherwise provided for
- H05K1/0237—High frequency adaptations
- H05K1/0243—Printed circuits associated with mounted high frequency components
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P5/00—Coupling devices of the waveguide type
- H01P5/02—Coupling devices of the waveguide type with invariable factor of coupling
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/0213—Electrical arrangements not otherwise provided for
- H05K1/0216—Reduction of cross-talk, noise or electromagnetic interference
- H05K1/0218—Reduction of cross-talk, noise or electromagnetic interference by printed shielding conductors, ground planes or power plane
- H05K1/0219—Printed shielding conductors for shielding around or between signal conductors, e.g. coplanar or coaxial printed shielding conductors
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/11—Printed elements for providing electric connections to or between printed circuits
- H05K1/117—Pads along the edge of rigid circuit boards, e.g. for pluggable connectors
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/14—Structural association of two or more printed circuits
- H05K1/141—One or more single auxiliary printed circuits mounted on a main printed circuit, e.g. modules, adapters
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
- H05K2201/09—Shape and layout
- H05K2201/09209—Shape and layout details of conductors
- H05K2201/09654—Shape and layout details of conductors covering at least two types of conductors provided for in H05K2201/09218 - H05K2201/095
- H05K2201/09781—Dummy conductors, i.e. not used for normal transport of current; Dummy electrodes of components
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
- H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
- H05K2201/10613—Details of electrical connections of non-printed components, e.g. special leads
- H05K2201/10621—Components characterised by their electrical contacts
- H05K2201/10689—Leaded Integrated Circuit [IC] package, e.g. dual-in-line [DIL]
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
- H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
- H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
- H05K3/3405—Edge mounted components, e.g. terminals
Definitions
- the present invention relates to a microwave cir ⁇ cuit, more specifically a microwave circuit according to the preamble of claim 1.
- Microwaves are the designation of electrical signals in the frequency range 0.5-50 GHz.
- Circuits for handling microwaves i.e. microwave circuits, generally consist of a substrate of aluminium oxide, or some other insulating material, on which conductors, resistors and optionally capacitors are built up by sputtering followed by the plating of patterns on the substrate. The other compo ⁇ nents are then soldered or glued on the substrate.
- the substrate is encapsulated in a capsule of conductive material.
- the circuit itself may be designed according to different principles.
- the microwave circuit disclosed therein consists of a substrate on whose upper side components and connections are arranged. This cir- cuit has conductors and a ground plane in a single plane, a so-called coplanar structure.
- the microwave circuit described therein is double-sided and consists of a substrate (26), on the upper side of which components are arranged and on the lower side of which a ground plane, coplanar conductors and connections are arranged. Through holes, being through-plated, are formed in the substrate for the connection of components directly to the ground plane and for electric connection of the connections to the inputs and outputs of the cir ⁇ cuit.
- the lower side of the substrate is generally soldered on a lead frame, to the leads of which external components and circuits are con ⁇ nected.
- a cover is soldered to the upper side of the cir- cuit. In this manner, the circuit is hermetically enclos ⁇ ed and electrically shielded.
- the part which in the known microwave circuits has the greatest adverse effect on the matching, and hence determines the upper limit frequency of the circuits, is the input/output conductor.
- Predominant factors for the impedance of a conductor are its width and its distance from the ground plane. In the double-sided design, it is possible to control the impedance of the conductor with high precision, except in a portion adjacent the through hole. The reason for this is that a region around the through hole has no ground plane, which is self-evident unless it should be grounded.
- the through hole also provides a certain inductance, however considerably less since one has managed to solve the matching thereof quite well.
- the compensation for the inductance of the third part, i.e. the connection lead, is relatively easy to achieve by means of a gap having a suitable width between the lead and the ground plane.
- the effect of the mismatch in the interface in most cases becomes acceptably small, but at higher frequencies and/or higher powers, the power loss becomes so noticeable that measures have to be taken to improve the matching.
- a certain improvement can be achieved by increasing the width of the conductor considerably in said portion, which lacks a ground plane below it. However, this does not solve the problem entirely and may also be a com ⁇ pletely impracticable way, for example when there is not sufficient room for the required widening.
- the above-mentioned US-4, 626, 805 shows another way of improving the matching.
- part of the ground plane is replaced by a coplanar conductor (30) , in one end (34) of which the through hole, or the via hole (40), is disposed and in the other end (32) of which the terminal for connecting another microwave circuit is located.
- the via hole con ⁇ nects the coplanar conductor to the input conductor (36) on the upper side of the substrate.
- a gap (6), surround- ing the end (34) of the coplanar conductor and the via hole, is provided.
- a capacitance which compensates for the inductances in the end of the input conductor and in the via hole, is then introduced, the width of the gap being dimensioned for obtaining the correct capacitance. This solution does not yield a satisfactory result.
- the gap gives rise to an inductance in the part of the input conductor located above the gap.
- the provision of a coplanar conductor on the lower side of the substrate entails that the via hole is positioned a considerable distance inside the edge of the substrate, and the input thus occupies a considerable, useless surface on the upper side of the substrate.
- US-4, 626, 805 also shows another embodiment, where an attempt has been made to compensate for the inductance obtained in the part of the input conductor which is located above the gap arranged on the lower side.
- a por ⁇ tion (T) of the input conductor is considerably widened, this giving a capacitive contribution.
- this com ⁇ pensation is not satisfactory because it is not made at the source of the mismatch.
- this type of compensa- tion feasible, since an increase of the capacitive con ⁇ nection by widening the conductor requires an underlying ground plane, which thus is not present where the mis ⁇ match occurs.
- One object of the present invention is to provide a microwave circuit with improved matching in the interface of the circuit as compared with known microwave circuits.
- Another object of the invention is to provide a microwave circuit having small power losses at frequen- cies up to above 26 GHz.
- Fig. 1 shows a part of a substrate with a matching pattern according to the invention
- Fig. 2 shows the matching pattern in detail; and Fig. 3 shows a portion of the lower side of the sub ⁇ strate.
- Fig. 1 shows a cut-away, enlarged portion of a sub- strate 1.
- the substrate 1 has a length of about 15-20 mm and a width of about 10-15 mm.
- the sub ⁇ strate 1 is arranged on a lead frame and is covered by a cover which hermetically encloses the substrate 1 and also produces a shielding effect.
- the lead frame and the cover are not shown, since they are of secondary impor ⁇ tance for the invention.
- microwave components and conductor patterns 3 are arranged (most of which are not illustrated for pur ⁇ poses of clarity), and on the lower side 4 of the sub- strate are provided a ground plane 5 and connections 6.
- the via holes 7 are through-plated or completely filled with conductive material.
- the via holes 7 are used for transmitting signals between the connec ⁇ tions 6 and conductors 3 or components, and for directly grounding the components on the upper side etc.
- the ground plane 5 covers the major part of the lower side 4, but leaves a gap 8 with bare substrate material around each connection 6 that is not to be grounded.
- On the upper side 2 are provided (see Fig. 1 ) a grounded frame 9, to which the cover is connected by soldering, an input (or an output) conductor 10 and an embodiment of a match ⁇ ing pattern 11 according to the present invention.
- Fig. 2 is a cut-away portion (further enlarged in relation to Fig. 1) of the substrate 1 as-seen from above.
- Fig. 3 shows a cut-away portion of the substrate 1 as seen from below.
- Fig. 3 is on the same scale as Fig. 1.
- the micro ⁇ wave circuit is well matched, i.e. that the impedance in the inputs and outputs of the circuit is the same as in the connected, external conductors.
- a common impedance is 50 ohm. If the impedance is not equal, signal reflections will result in the junction, which means power losses.
- the critical junction is the connection 6, the via hole 7 and a part of the input con ⁇ ductor 10, which will be explained in more detail hereinbelow.
- the input conductor 10 extends at right angles to an end edge 12 of the substrate 1, from the via hole 7 and inwards to an input component of the circuit.
- the factors which, in the type of circuit design here shown, have the greatest impact on the impe ⁇ dance of a conductor are the distance of the conductor to the ground plane and the width of the conductor. Since substantially the entire lower side 4 of the substrate 1 is covered by the ground plane and the thickness of the substrate is well-defined, it is relatively easy to dimension the input conductor 10 so that its impedance becomes 50 ohm. There is however one important exception to this.
- the collar 13 is provided when plating the via hole 7. This results in a mismatch which primarily has a substantial adverse effect at fre ⁇ quencies above about 8 GHz, the power losses increasing heavily with increasing frequency.
- the input conductor 10 constitutes an extra inductance giving an excessive total impedance. To this come induc ⁇ tances caused by the collar 13, in the via hole 7 and in the connection 6. The whole of this incompletely matched part, i.e.
- connection 6 the via hole 7, the collar 13 and the end portion 14, will be referred to herein ⁇ after as interface.
- the inductance in the connection 6 is compensated for according to known technique, by dimen ⁇ sioning the gap 8 for suitable capacitive connection to the ground plane 5.
- the problem of mismatch in the rest of the interface is solved practically completely by the provision of the matching pattern 11.
- the matching pattern introduces a capacitive counterbalance to the inductances in the entire interface even if it primarily eliminates the mismatch in the end portion 14 and the collar 13.
- the matching pattern 11 is connected to the ground plane 5 through via holes 15 and may thus be considered as an extra ground plane placed on the upper side 2.
- the matching pattern 11 consists of two parts which are sym ⁇ metrically arranged on both sides of the input conductor 10 and which are stepped, i.e. they have a stepped bound ⁇ ary line with two steps facing the input conductor 10. Study the lowermost portion of the matching pattern in Fig. 2. What is said below about this portion also simi ⁇ larly applies, because of the symmetry, to the other por ⁇ tion.
- the first and second steps 16 and 17, respectively, of the stepped part are parallel to the input conductor 10 and differently spaced from the input conductor 10 so as to form, respectively, a first and a second gap 18 and 19, respectively.
- the first step 16 extends along the end portion 14 from the rim of the opposite gap 8 towards the pattern portion 13 and leaves only a portion immediately adjacent the pattern portion 13 where the second step 17 starts.
- the second step 17 extends up to an imaginary straight line which is perpendicular to the step 17 and passes through the centre of the via hole 7.
- This matching pattern 11 thus introduces a capaci ⁇ tive counterbalance to the above-mentioned inductance in the end portion 14 and the pattern portion 13 by intro ⁇ ducing a capactive connection to the ground plane.
- the matching pattern 11 can be designed by minor changes so as to also compensate for the inductance in the via hole 7. If so desirable, the matching pattern 11 may also be designed so as to compensate for part of the inductance/capacitance of the connection 6, the gap 8 being adjusted to a corresponding extent.
- the width of the gaps is essential to the impedance in the region.
- the width of the input conductor is 0.24 mm; the width of the first gap 18 is 0.1 mm and the width of the second gap 19 is 0.3 mm.
- the via hole 7 has a diameter of 0.25 mm and its centre is located 0.25 mm from the nearest side edge of the end portion 14.
- the length of the first step 16 is 0.45 mm, and the length of the second step 17 is 0.35 mm.
- the distance between the end portion 14 and the nearest lead-through 15 is 1.0 mm in this microwave cir- cuit, which is intended for use at about 10 GHz. This distance may be arbitrarily short but should not exceed a 1/8 wavelength (i.e. ⁇ /8). In this example, it is suit ⁇ able to maintain the distance below about 2.0 mm. In the frequency range where the microwave circuit according to the invention is intended to operate, the upper limit of this distance is about 3.0 mm in practice.
- the thickness of the substrate 1 generally is 0.25 mm, 0.38 mm or 0.64 mm, and in this case it is 0.25 mm. This thickness determines the width of the conductor 10, which in turn primarily deter ⁇ mines the width of the gap 18.
- the width of the conductor 10 and the length of the step 16 may extend along a minor part of the conductor 10 with a simultaneous decrease of the width of the gap 18
- the width of the gap 18 may vary between almost 0 and about 0.5 mm, the lower limit being essentially determined by what is feasible in terms of manufacturing technique (today about 0.01 mm).
- the design of the matching pattern can be changed according to the conditions concerning the design of the conductor, the thickness of the substrate, the extent and the shape of the ground-planeless portion on the lower side of the substrate and so forth.
- the matching pattern need not be connected to the frame.
- the number of via holes in the matching pat- tern may vary.
- the matching pattern can be designed so as to give a higher capacitance than in the embodiment described above to compensate for the inductance in the via hole.
- the match- ing pattern can, if so desired, be designed for example so as not to compensate for the mismatch in the pattern portion around the via hole. This however yields a poorer result at higher frequencies, but may nevertheless confer certain advantages.
- the symmetry which the match- ing pattern exhibits in the illustrated embodiment neces ⁇ sary.
- the stepped shape of the matching pattern should be considered as an example only. The periphery of the matching pattern may of course be given any other shape, provided the result is that intended by the inven- tion.
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP94928544A EP0721676A1 (en) | 1993-09-27 | 1994-09-26 | Microwave circuit |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9303142-5 | 1993-09-27 | ||
SE9303142A SE500982C2 (en) | 1993-09-27 | 1993-09-27 | Microwave circuit with impedance interface interface |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1995009452A1 true WO1995009452A1 (en) | 1995-04-06 |
Family
ID=20391225
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/SE1994/000888 WO1995009452A1 (en) | 1993-09-27 | 1994-09-26 | Microwave circuit |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0721676A1 (en) |
SE (1) | SE500982C2 (en) |
WO (1) | WO1995009452A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1997001872A1 (en) * | 1995-06-27 | 1997-01-16 | Sivers Ima Ab | Microwave circuit, capped microwave circuit and use thereof in a circuit arrangement |
US7956623B2 (en) | 2007-02-16 | 2011-06-07 | Countlab, Inc | Container filling machine |
US10577186B2 (en) | 2011-08-18 | 2020-03-03 | Countlab, Inc. | Container filling machine |
US20220295630A1 (en) * | 2021-03-15 | 2022-09-15 | Sumitomo Electric Industries, Ltd. | Printed board and printed board assembly |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4626805A (en) * | 1985-04-26 | 1986-12-02 | Tektronix, Inc. | Surface mountable microwave IC package |
US5057798A (en) * | 1990-06-22 | 1991-10-15 | Hughes Aircraft Company | Space-saving two-sided microwave circuitry for hybrid circuits |
US5097233A (en) * | 1990-12-20 | 1992-03-17 | Hughes Aircraft Company | Coplanar 3dB quadrature coupler |
-
1993
- 1993-09-27 SE SE9303142A patent/SE500982C2/en not_active IP Right Cessation
-
1994
- 1994-09-26 EP EP94928544A patent/EP0721676A1/en not_active Withdrawn
- 1994-09-26 WO PCT/SE1994/000888 patent/WO1995009452A1/en not_active Application Discontinuation
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4626805A (en) * | 1985-04-26 | 1986-12-02 | Tektronix, Inc. | Surface mountable microwave IC package |
US5057798A (en) * | 1990-06-22 | 1991-10-15 | Hughes Aircraft Company | Space-saving two-sided microwave circuitry for hybrid circuits |
US5097233A (en) * | 1990-12-20 | 1992-03-17 | Hughes Aircraft Company | Coplanar 3dB quadrature coupler |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1997001872A1 (en) * | 1995-06-27 | 1997-01-16 | Sivers Ima Ab | Microwave circuit, capped microwave circuit and use thereof in a circuit arrangement |
US5994983A (en) * | 1995-06-27 | 1999-11-30 | Sivers Ima Ab | Microwave circuit, capped microwave circuit and use thereof in a circuit arrangement |
US7956623B2 (en) | 2007-02-16 | 2011-06-07 | Countlab, Inc | Container filling machine |
US10577186B2 (en) | 2011-08-18 | 2020-03-03 | Countlab, Inc. | Container filling machine |
US20220295630A1 (en) * | 2021-03-15 | 2022-09-15 | Sumitomo Electric Industries, Ltd. | Printed board and printed board assembly |
US11744008B2 (en) * | 2021-03-15 | 2023-08-29 | Sumitomo Electric Industries, Ltd. | Printed board and printed board assembly |
Also Published As
Publication number | Publication date |
---|---|
EP0721676A1 (en) | 1996-07-17 |
SE9303142L (en) | 1994-10-10 |
SE9303142D0 (en) | 1993-09-27 |
SE500982C2 (en) | 1994-10-10 |
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