CN101953019B - The spiral coupler improved - Google Patents

Abstract

The invention discloses an improved spiral coupler, comprising: a plurality of parallel and co-extending conductive strips arranged in a planar spiral channel, the conductive strips include a first conductive strip and a second conductive strip, the first conductive strip a strip has an input port and a direct or through port, the second conductive strip has a coupling port and an isolation port; and a first jumper connection for bridging the conductive strip from the inside of the spiral channel to the outside to All four ports are provided for external access to the helical channel.

Description

Improved Spiral Coupler

technical field

The present invention relates to an improved screw coupler.

Background technique

With the rapid development of radio communication and satellite communication systems, there is an increasing demand for highly integrated radio frequency (RF) and microwave circuits with better performance, smaller size and lower cost. Many of these systems use couplers, such as three-decibel (3-dB) couplers and other directional couplers, in their microwave circuits. Many types and variations of couplers have been developed for use in circuits that process microwave frequency signals. Lange's US Patent 3,516,024, issued June 2, 1970, is an "Intercrossing Stripline Coupler". The coupler was published in "Interdigitated Strip-Line Quadrature Hybrid (Interdigitated Strip-Line Quadrature Hybrid)" published by Lange, MTTS Digestof Technical Papers, Dallas, Texas, May 5-7, 1969, pp.10-13 Also described in , this coupler is known to the public as a Lange coupler. Since the early work on stripline conductors, many variations have been developed.

These variations are described in various ways in Waterman, Jr. et al., "GaAs Monolithic Lange and Wilkinson Couplers" and Brehm et al., "GaAs Monolithic Lange and Wilkinson Couplers" Monolithic GaAsLange Coupler at X-Band (X-band monolithic gallium arsenide Lange coupler)", the two were published in IEEE Transactions on Electron Device (IEEE Electronic Devices Journal), Vol.ED-28, No.2, February 1981, pages 212-216, and pages 217-218; "Monolithic Hybrid Quadrature Couplers (Braided Structures)" by Tajima et al., IEEE GaA IC Symposium, 1982, pages 154 and 155; "Monolithic GaAs Interdigitated Couplers" by Kumar et al., IEEE, 1983, pages 359-362; "Ultra-Wideband Quadrature Coupler" by Kemp et al. Frequency Quadrature Coupler)", IEEE Transactions, 1983, pp.197-199; "Microstrip Spiral Directional Coupler (Microstrip Spiral Directional Coupler)" by Shibata et al., IEEE Transactions, 1981, pp.680-689; Lentz's US Patent 3,162,717 "Compact Transmission line Consisting of Interleaved ConductorStrips and Shield Strips" issued December 22, 1964; Oh's published July 18, 1967 in the United States Patent 3,332,039 "ThreeConductor Coplannar Serpentine-line Directional Coupler"; Presser et al., US Patent 4,636,754 "High performance Interdigitated Coupler withAdditional Jumper Wire (with additional jumper wire, high performance, inter-crossing coupler)"; and U.S. Patent 4,800,345 "Spiral Hybrid Coupler (spiral hybrid coupler) published on January 24, 1989 by Podell et al. )". All of these above cited references are hereby incorporated by reference in their entirety.

Different forms of these inter-crossing stripline conductors provide coupling with varying degrees of success for different manufacturing processes.

Contents of the invention

It is therefore an object of the present invention to provide an improved screw coupler.

Another object of the present invention is to provide an improved spiral coupler suitable for use in semiconductor and other planar fabrication processes.

It is a further object of the present invention to provide an improved helical coupler having the simplicity of a Lange coupler but with reduced size and improved performance.

Still another object of the present invention is to provide an improved helical coupler having improved insulation and directivity.

Yet another object of the present invention is to provide an improved helical coupler in which all ports of the coupler are located outside the helical channel.

The present invention is achieved in the following manner: An improved helical coupler is obtainable by: a plurality of parallel, coextensive conductive strips arranged in a planar helical channel; and a cross-over connection ), the jumper connection is used to bridge the conductive strip from the inside to the outside of the helical channel to provide all four ports located outside the helical channel.

However, the inventive subject matter need not achieve all of these objectives in other embodiments, and the claims of the invention should not be limited to structures or methods that achieve these objectives.

The present invention is characterized in that: an improved spiral coupler includes: a plurality of parallel, co-extending conductive strips arranged in a planar spiral channel, the conductive strips include: a first conductive strip, the first conductive strip having an input port and a direct or through port; and a second conductive strip having a coupled port and an isolated port; the coupler also includes a first jumper connection for connecting the The conductive strips bridge from the inside to the outside of the helical channel to provide all four ports accessing the helical channel from the outside.

In a preferred embodiment, the helical channel may be symmetrical and the first bridging connection may be on the axis of symmetry. There may be only two conductive strips. The improved spiral coupler may also include a second jumper connection for mutually exchanging the relative positions of the first conductive strip and the second conductive strip in the spiral channel. The helical channel may be symmetrical and the second jumper connection may be on the axis of symmetry. A second jumper connection may be provided at the midpoint of the helical channel. Each conductive strip may comprise a plurality of discrete parallel elements that intersect with discrete parallel elements of other conductive strips. There may be many loops in the spiral channel, each loop having a first jumper connection and a second jumper connection. Multiple discrete elements in each conductive strip can be re-tracked together at the jumper connections to present a single conductor member for bridging. There may be a plurality of spaced shunts interconnected between elements of each bar spaced along the helical channel.

The present invention is also characterized in that an improved four-port helical directional coupler includes: parallel, coextensive first and second conductive strips disposed in a planar helical channel, the first conductive strip having an input port and a direct or through port, the second conductive strip has a coupled port and an isolated port; and a first jumper connection for bridging the conductive strip from the interior of the spiral channel to external to provide all four ports external to the helical channel.

In a preferred example, the helical channel may be symmetrical and the first bridging connection may be on the axis of symmetry. The improved four-port spiral coupler may further include a second jumper connection for mutually exchanging the relative positions of the first conductive strip and the second conductive strip in the spiral channel. The second bridging connection may be on the axis of symmetry. A second jumper connection may be provided at the midpoint of the helical channel. Each conductive strip may comprise a plurality of discrete parallel elements that intersect with discrete parallel elements of other conductive strips.

Description of drawings

Other objects, features and advantages of the present invention will appear to those skilled in the art from the following description of preferred embodiments and accompanying drawings, in which:

Figure 1 is a schematic plan view of a prior art directional coupler on a substrate;

Figure 2 is a view of a prior art Lange-type mutually bridged directional coupler similar to that of Figure 1;

Figure 3 is a schematic plan view of a prior art helical directional coupler;

Figure 4 is a schematic plan view of a helical coupler according to the invention on a substrate;

Fig. 5 is a view similar to Fig. 4, wherein each conductive strip has discrete elements that bridge each other;

Figure 6 is a view similar to Figure 5, wherein the helical channel includes two loops;

Fig. 7 is a view similar to Fig. 6, wherein the elements in each conductive strip are directly connected in parallel at the crossover without being converted tracks together;

Figure 8 is a view similar to Figure 5, wherein the helical channel includes four loops; and

Fig. 9 is a view similar to Fig. 5, wherein the helical channel comprises a two-turn loop.

detailed description

Besides the preferred embodiments disclosed below, the invention is capable of other embodiments and of being practiced or carried out in various ways. It is therefore to be understood that the invention, in its application, is not limited to the details of construction and arrangement of parts mentioned in the following description or shown in the drawings. If only one embodiment has been described herein, the claims herein are not limited to that embodiment. Furthermore, the claims herein are not to be read restrictively unless there is clear and convincing evidence for some exclusion, limitation, or disclaimer.

The present invention proposes a solution which not only reduces the size of directional couplers, especially Lange couplers, but also improves insulation and directivity. The proposed layout is similar to that in a standard Lange coupler, requiring only one layer of metal for the striplines and another layer for bridging the jumper connections. The resulting couplers can be reduced in size to one-third to one-sixth the size of standard quarter-wave couplers. The two strip conductor sections of the coupler are wound parallel to each other to form one or more complete helical loops by appropriately bridging each other along a symmetrical centerline. In the present invention, the lengths of the coupled striplines are equal to each other, and the symmetry of the structure enables the input port, the coupled port, the direct or through port, and the isolated port to respond to each other.

To maintain the structural symmetry of the helical loop form, all four ports of the coupler are symmetrically connected to the outer circle of the helical loop. In addition, at the interconnection between the inner loop and the outer inner loop, the coupler's conductor pair consisting of two conductor strips entering the inner loop from the outer loop and the pair of conductor strips connected from the inner loop to the outer loop are connected to each other. join. This can be achieved at the PCB board level and at the semiconductor die level by standard microstrip technology. The jumper is positioned along the centerline of symmetry of the coupler.

In order to keep the line lengths of the coupled conductor strips the same, the semiconductor strips are bridged across each other within the coupler pair at the midpoint of the spiral loop. Thus, each conductor strip travels half way along the inside of the loop and half way along the outside of the loop. For this purpose, a jumper between the inner loop and the outer loop with a conductor located on the second layer can be used. There are two alternative ways to achieve this jumper: use a jumper bridge for each conductor bar as shown in the example of a two conductor bar coupler as shown in Figure 4, or use a jumper bridge as shown in Figure 5 The jumper bridging shown in the four conductor strip coupler example shown after switching multiple conductor strips together to track. The first type of crossover introduces less parasitics and has a wider bandwidth, while the second type of crossover helps reduce the size of the crossover portion.

In addition to making the wire lengths of the conductor strips equal, adjacent conductor strips between the inner and outer circles are from the same conductor, and electromagnetic waves propagate in the same direction. The even mode impedance of the coupler of the present invention is higher than that of a conventional spread coupler with the same bar width and spacing, while the odd mode impedance is close to that of a conventional spread coupler. With these properly controlled mutual couplings between loops, high coupling ratios such as three decibels can be easily obtained at wide bandwidths without the need to use small spacing between conductor strips. In addition, high insulation and directivity can be obtained in the proposed spiral coupler. In addition to these two jumper bridges along the symmetrical center loop of the proposed coupler loop, jumper connections can also be added near the corners of the loop to reduce the phase distribution, which also helps to increase the coupling. To cover lower frequencies or obtain smaller circuit sizes, several coupling loops can be connected in series to form a multi-loop coupler, as shown in Figure 6-8, where two to four loops have been connected in series and adjacent The loops have been oriented such that their mutual coupling contributes to improved overall performance. Another alternative is to use a multi-turn helical structure by introducing more loops around the same center, as shown in Figure 9, where a single loop form as shown in Figure 5 is used around the single loop form second circuit.

A prior art four port directional coupler 10 comprising two conductor bars 12 and 14 is shown in FIG. 1 . The conductor bar 12 has an input port 16 and a direct or through port 18 . The conductor bar 14 has a coupling port 20 and an insulating port 22 . The length of the conductor strips 12 and 14 is roughly equal to 1/4 of the wavelength of the central operating frequency (e.g., for a coupler designed for 3GHz applications), which is about 1 cm long if the circuit is fabricated using a high frequency semiconductor process . The width of the conductor strips and the gaps between them are designed to optimize coupling efficiency or transfer efficiency. The width w of conductor strips 12 and 14 and the gap g between them are approximately uniform and are chosen to optimize transfer efficiency. Typical coupling efficiencies are in the range of 10%, ie, 10-dB coupling ratio. A modification of the prior art arrangement is shown in Figure 2, where a four port directional coupler 10a is of the Lange type, wherein each conductor bar 12a and 14a is formed by a plurality of elements 12aa and 12aaa, 14aa and 14aaa. This provides higher coupling with a transfer efficiency in the range of 50%, ie, a 3-dB coupling ratio. The widths of the elements 12aa, 12aaa, 14aa, 14aaa, like the gaps, are generally consistent and are all selected to optimize transfer efficiency.

In another prior art approach shown in FIG. 3, a four-part directional coupler 30 is constructed as a planar helix with two conductor strips 32 and 34 extending inwardly in a helix that begins at the input port 36 and coupling port 35 and terminates in direct or through port 40 and insulated port 38. One disadvantage of this design is that in this case two of the ports (direct or through end 40 and insulated port 38 ) end inside their helixes which are not easily accessible. Another disadvantage of the spiral coupler of FIG. 3 is that in order to balance the coupling and equalize the coupling throughout the length of the conductor strips 32 and 34, the width of the gap changes, for example, having a width g1 at one location and a width g1 at another location. g2.

In FIG. 4 , an improved four-port symmetrical helical directional coupler 50 according to the present invention can be disposed on a substrate, such as a suitable PCB board, semiconductor substrate or other planar manufacturing material 52 . Spiral coupler 50 includes a plurality of conductive strips, eg, a first conductive strip 54 and a second conductive strip 56 . The first conductive strip 54 has an input port 58 at one end and a direct or through port 60 at the other end. The second conductive strip 56 has a coupling port 62 at one end and an isolation port 64 at the other end. The helical coupler 50 is in the form of a single symmetrical loop 66 having a symmetrical centerline 68 . A first jumper connection 70 is provided at the centerline of symmetry 68 and uses transition track sections 72 and 74 to guide the conductive strips 54 and 56 from the outside to the inside of the helical channel indicated at 76, allowing the input port 58 and the coupling port 62 as well as the direct port 60 and the insulated port 64 are located outside the helical channel 76 . The second jumper connection 80 can also be utilized using, for example, a transition track portion 82 , but in this case the jumper connection is used to exchange the relative positions of the first conductor bar 54 and the second conductor bar 56 . Thus, viewing from right to left at the top of the loop in FIG. 4, the first conductive strip 54 is at the top or right and the second conductive strip 56 is at the bottom or left. After the swap at the jumper connection 80, the first conductive strip 54 is on the left or bottom and the second conductive strip 56 is on the right or top. Doing so equalizes the lengths of the bars in the helix and further balances the coupling effect of the coupler 50 . While the jumper connection 70 is preferably on the symmetrical centerline 68 , the second jumper connection 80 is preferably on the symmetrical centerline 68 and also at the midpoint of the first conductive strip 54 and the second conductive strip 56 .

The method of the present invention as shown in FIG. 4 can be applied in the crossover configuration of FIG. 5, wherein coupler 50a includes conductor bar 54a and conductor bar 56a, conductor bar 54a having a plurality of conductor elements, such as conductor elements 54aa and 54aaa , while the conductor bar 56a has a plurality of elements, such as conductor elements 56aa and 56aaa. Now in the jumper connection 70a, the ends of the elements 56aa and 56aaa are connected together at the transition track portions 82 and 84 and also at the transition track portions 86 and 88, and by bridging the transition track portions 90 and 92 interconnected. Likewise, conductor elements 54aa and 54aaa have their ends connected together at transition track portions 94 , 96 , 98 and 100 and interconnected by jumper conductors 102 and 104 . Similarly, but more simplified, at second jumper connection 80a, elements 56aa and 56aaa are connected by jumper transition track portions 106 and 108, while conductor elements 54aa and 54aaa are jumper connected by jumper track portions 110 and 112. As also shown in FIG. 5, multiple auxiliary transition track sections 114 are present throughout the loop 66a of the coupler 50a, most commonly in the corner regions, to further balance coupling and improve transfer efficiency.

Although the invention has hitherto been shown with a single loop as shown in Figures 4 and 5, this is not a necessary limitation of the invention. As shown in Figure 6, there may be two loops 66a, 66b, each loop having a first jumper connection 70a, 70b and a second jumper connection 80a, 80b. FIG. 7 shows an alternative configuration for the first jumper connections 70 a , 70 b of FIG. 6 . In Figure 7, jumper connections 70'a and 70'b do not use the intended transition track portion prior to entering the jumper connection. Instead, four separate jumper transition track portions 116, 118, 120, and 122 are used for elements 54aa and 54aaa, four jumper transition track portions 124, 126, 128, and 130 are used for conductor elements 56aa and 56aaa, and similar A jumper conductor is used for the second jumper connection 70'b. The coupler according to the present invention can be extended as required, for example, in FIG. 8, a coupler 50"'a is shown which comprises four loops 66a, 66b, 66c and 66d, each loop has its own first jumper connections 70a, 70b, 70c and 70d, and second jumper connections 80a, 80b, 80c and 80d. Furthermore, a coupler according to the invention may be extended around the same loop center, for example, in Figure 9, a coupler 50b is shown comprising: an additional loop 60a around the loop 60b used in Figure 5 ; first jumper connections 70a and 70b; and second jumper connections 80a and 80b.

Although specific features of the invention are shown in some drawings and not in others, this is for convenience of illustration only and each feature may be combined with any or all of the other features in accordance with the invention. The terms "comprising", "including", "having" and "with" as used herein are to be construed broadly and comprehensively and are not limited to any substantial interconnection. Moreover, any embodiment disclosed in the subject matter of the present application is not to be considered as the only possible embodiment.

Furthermore, any amendment made during the prosecution of a patent application for this patent is not a disclaimer of any claim element mentioned in the filed application: one skilled in the art cannot reasonably be expected to write a text containing Claims of all possible equivalents, many of which were unforeseeable at the time of modification and would exceed a fair interpretation of what is to be waived (if any), the rationale underlying the modification may simply be related to Numerous equivalents are less relevant, and/or there are numerous other reasons why applicants are not expected to state some non-essential substitution for any amended claim element.

Those skilled in the art will appreciate that other embodiments are within the scope of the following claims.

Claims (18)

1. An improved spiral coupler, comprising: a plurality of parallel, coextensive conductive strips disposed in a planar spiral channel, the conductive strips comprising a first conductive strip and a second conductive strip, the first conductive strip having an input port and a direct or through port, the The second conductive strip has a coupled port and an isolated port, wherein the parallel, coextensive first conductive strip and the second conductive strip mean that the first conductive strip and the second conductive strip extend parallel together in the same direction; A first jumper connection for bridging the first and second conductive strips in parallel on themselves from the outside to the inside of the helical channel to provide all four slave external access to the port of the helical channel; and A second bridging connection, the second bridging connection is used to mutually exchange the relative positions of the first conductive strip and the second conductive strip in the spiral channel. 2. The improved helical coupler of claim 1, wherein the helical channel is symmetrical and the first jumper connection is located on the axis of symmetry. 3. The improved spiral coupler of claim 1 wherein there are only two conductive strips. 4. The improved helical coupler of claim 1, wherein the helical channel is symmetrical and the second jumper connection is on the axis of symmetry. 5. The improved helical coupler of claim 1, wherein the second jumper connection is provided at a midpoint of the helical channel. 6. The improved helical coupler of claim 1, wherein each conductive strip includes a plurality of discrete parallel elements that intersect with those of other conductive strips. 7. The improved helical coupler of claim 1, wherein there are a plurality of loops in the helical channel, each loop having a first jumper connection and a second jumper connection. 8. The improved helical coupler of claim 6, wherein a plurality of discrete parallel elements in each conductive strip are re-tracked together at the jumper connection to appear as a single conductive member for bridging . 9. The improved helical coupler of claim 6, wherein there are a plurality of spaced transition track portions at each conductive strip spaced along said helical channel components are interconnected. 10. The improved screw coupler of claim 1, said input port and said coupled port are adjacent to each other, and said direct or through port and said isolation port are adjacent to each other. 11. The improved screw coupler of claim 10, said input port and said coupled port being on opposite sides of the screw coupler than said direct or through port and said insulated port. 12. An improved four-port helical directional coupler comprising: Parallel, coextensive first and second conductive strips disposed in a planar spiral channel, the first conductive strip having an input port and a direct or through port, the second conductive strip having a coupled port and an isolated port , wherein parallel, coextensive first conductive strips and second conductive strips mean that the first conductive strips and the second conductive strips extend parallel together in the same direction; A first jumper connection for bridging the first and second conductive strips in parallel on themselves from the outside to the inside of the spiral channel to provide all four said port external to said helical channel; and A second bridging connection, the second bridging connection is used to mutually exchange the relative positions of the first conductive strip and the second conductive strip in the spiral channel. 13. The improved four port helical directional coupler of claim 12, wherein the helical channel is symmetrical and the first jumper connection is on the axis of symmetry. 14. The improved four port helical directional coupler of claim 12, wherein the second jumper connection is located on the axis of symmetry. 15. The improved four-port helical directional coupler of claim 12, wherein the second jumper connection is provided at a midpoint of the helical channel. 16. The improved four-port helical directional coupler of claim 12, wherein each strip comprises a plurality of discrete parallel elements intersecting with those of the other strips . 17. The improved four port helical directional coupler of claim 12, said input port and said coupled port are adjacent to each other, and said direct or through port and said isolation port are adjacent to each other. 18. The improved four-port helical directional coupler of claim 17, said input port and said coupling port being located in said four-port helical directional coupler compared to said direct or through port and said insulated port on the opposite side of the .