DE2241711A1 - RIBBON CIRCULATOR IN A TRIANGLE CONNECTION - Google Patents

Description

Ribbon circuit circulator in delta connection

The invention relates to a strip line circulator in delta connection with at least one ground plane and a strip line arrangement above the ground plane, the three ribbon line branches arranged rotationally symmetrically about a central axis and one of these branches one after the other having conductive tape connecting in a series loop,. also with a core made of gyromagnetic material, which is located on the central axis and couples the sections of conductive tape together when one of the Branches is excited by high frequency wave energy relative to the ground plane.

The known embodiment of a constant circulator constructed with concentrated circuit elements is analytical in articles by Deutsch "and Wieser, IEEE Transactions on Magnetics , Volume 2, No 3, September 1966, pages 278-282; Konishi, IEEE Transactions on Microwave Theory and Techniques , Volume 13 , November 1965, pages 852-864; Davis and Cohen, IEEE Transactions on Microwave Theory and Technologies, Volume 11, November 1963, pages 506-512; and in U.S. Patents 3,335,374, 3,538,459, 3 573 665 and 3 6o5 o4o treated.

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In general, a circulator of this type has a disc-shaped ferrite core and three branches which in threefold symmetry radially with respect to the core are arranged. Each branch also has a resonant circuit with an inductive conductor and a special capacitive element, which are coupled through the core in a common zone. The circulator effect depends on the relationship between the response behavior of the resonant circuits to three guided in them Modes, namely an in-phase mode and two modes rotating in opposite directions. The responsiveness will be typically analyzed by the (oscillation) excitation at a branch of the junction divided into three stimuli, which include the stimulus of all three branches. The three suggestions correspond to the eigenvectors for the scattering matrix of the junction. A first suggestion corresponds to this in-phase modes, while the remaining two excitations have phases which lead to oppositely rotating Leading fashions. The circulation condition, expressed in terms of these stimuli, is that the reflection coefficients correspond to the eigenvalues for the scattering matrix are out of phase with each other by 120 degrees as precisely as possible. The structural design is included so that each branch goes through one on top of the core

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22417M

arranged ribbon line is formed. When these banulines are connected to high frequency energy sources they show the required inductive reactances with their fields coupled across the core and with certain capacitors assigned to each branch in order to bring about the required resonance. In all known embodiments are the inductive reactances are provided in a Y or star connection, in preferred embodiments requires an isolated physical line crossing in the common area. However, it is already recognized been that every Y or star connection theoretically has an equivalent delta or triangle connection; to use this equivalence in circulators, was suggested in U.S. Patent 3,286,2ol. '' The delta connection avoids the necessary with the star connection physical intersection lines and enables therefore a simpler construction of the circulator. The delta connection previously envisaged made possible on the other hand, there was insufficient separate voting the in-phase and counter-rotating modes to create a satisfactory circulator effect.

It was reserved to the invention to solve this problem with ribbon line circulators in a delta connection.

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Based on your tape line circulator of the beginning specified type, the invention proposes for this purpose that a capacitance between the ribbon line arrangement and an intermediate point located between the stripline arrangement and the ground plane, and another Capacitance between the intermediate point and the ground plane are switched on.

A development of the invention is that the capacitance between the ribbon line arrangement and the Intermediate point through one on a branch of the ribbon line arrangement connected conductive tab is formed, which at least part of the gyromagnetic core overlaps the opposite side of the surface coupling the sections of the conductive connecting tape and spaced from a conductive part at the intermediate point.

In addition, the invention is further developed in that the conductive tape connecting the branches is formed by gaps is divided into sections in order to tune oppositely rotating modes of the circulator series capacitances to introduce.

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The invention is based on the knowledge that the delta connection in coordination with a special one Capacitance network a separate tuning for the in-phase modes and the oppositely rotating modes. Modes enable, creating the simple delta connection is made functional and the complication caused by crossings is avoided.

In an expedient embodiment, the strip line arrangement has the shape of a simple ring in the common area to which the input-output branches in mutually .equid distance are connected, the connection points being the vertices of the delta connection form. Three capacitors, each connected from each vertex to a common connection point, and another one from the common connection point to the stripline ground plane complete the tuning network.

In a preferred embodiment, these capacitors are made by a single thin, conductive and flat Component formed, which is used between the strip line arrangement and the ground plane and from .this at a distance is arranged. It can be shown that the capacitors thus formed are between the ribbon line arrangement and the intermediate level are individual for each branch

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and all three modes affect, but that between the intermediate level and the ground level capacitor is assigned to all branches in common and only the in-phase modes, because currents due to the oppositely rotating modes in the cancel common capacitor. Therefore, the phase of the in-phase mode can be independent of the phases of the oppositely rotating modes can be set to achieve the circulation.

In the drawing show:

Fig. 1 is a perspective view with a broken away part of the new circulator;

Fig. 2 shows an equivalent circuit of the circulator of Fig. 1;

FIG. 3 shows a modification of the equivalent circuit according to FIG. 2;

4 shows a partial cross-sectional view of a modification the embodiment of Figure 1; U.N

Figures 5, 6, 7 and 8 are plan views of alternative ones

Configurations of the embodiment according to Fig. 1 »

The circulator shown in Fig. 1 has three ribbon line central conductors 11, 12 and 13, which are arranged rotationally symmetrically on the top of a substrate 14 are. The substrate 14. itself comprises a plate made of magnetically polarized gyromagnetic material »

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which is usually a ferrite or a substituted garnet. Each strip or band is conductive with one Ring 15 made of a conductive strip material at the same mutual distance along the outer circumference of the ring 15 lying points connected or formed in one piece with the ring 15 in a corresponding arrangement. The senior Material can be removed from the center of the ring 15 so that its strip width is the same or different of the widths of the bands 11, 12 and 13 in order to be able to set the characteristic line resistances; however, this dimension does not appear to be critical. A larger width of the ring compared to the tape line gives the ring a characteristic line resistance that is less than that of the ribbon line, like this is desirable in some designs. As a rule, the outer diameter of the ring 15 is in the order of magnitude from 1/2 to 1/8 the wavelength of the intended operating frequency in the material of the substrate 14. The entire line pattern can be built up on the substrate 14 with the aid of thin-film, photolithographic processes, which at printed circuits are known.

An intermediate conductive plane 16 is disposed near the bottom of the ferrite substrate 14 and may, for example be a conductive layer like that on substrate 14. Level 16 should be at least as big as the

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Be ring 15; it can also be bigger and about that Ends of the strips 11, 12 and 13 protrude to provide additional capacity for the respective strips or strips. To achieve tapes in the overall size according to the state of the art specified above. A senior Ground plane 17 is supported by dielectric spacers! 18 held at a distance from the intermediate level 16. The level 17 goes continuously into the one with the free ones Ends of the conductors 11, 12 and 13 connected to circuits associated with ground planes above or at least with these connected so that when one of the conductors is excited as an input by high-frequency electromagnetic Wave energy relative to the ground plane 17, the two sections lying adjacent to the excited bands of the ring 15 are excited at the same time.

The equivalent circuit of the resulting circulator is shown in FIG. The three sections of the ring between the branches or connections are inductive at the operating frequency and can be connected in delta connected inductances 21, 22 and 23 are shown. In this delta connection, the three are vertices connected to the input connections of the branches 11, 12 and 13. The capacity of ring 15 (and the one in the Sections of the strips 11, 12 and 13) transitioning to level 16 to the Zv.'ischon level 16 are naturally distributed. However, since

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the portions of the ring 15 between the branches are inductive has those closest to an excited branch lying capacitance has a far greater influence on the currents caused by this excitation than the capacitance further away along the inductance. In other words, the capacity can be in a equivalent capacity as capacitances 24, 25 and 26 from each vertex to a common point 27 be transformed. The capacitance between the intermediate plane 16 and the ground plane 17 is by one Capacity 28 shown.

The circuit of Fig. 2 makes it clear that the shape of an intermediate ground plane 16 is physically appropriate is, however, the required capacities are represented by concentrated fixed capacitors Places can be provided. Even if the ribbon line arrangement according to FIG. 1 is in the form of an asymmetrical one Transmission line is present, it can be seen that a second ground plane and / or a second intermediate plane can be placed over the structure shown either with or without a second ferrite body, to create a balanced transmission line arrangement. The extra capacity between the second In this case, the intermediate level and the second ground level would be connected in parallel with the capacitors according to FIG.

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The general parameters required for circulation are in the patents referenced above and publications are fully described and do not need to be repeated here. Combined with the invention, however, is the type of control as provided by the capacitor network 24, 25, 26 and 28 is made possible, of importance.

One should therefore bear in mind that the in-phase mode can be applied simultaneously to branches 11, 12 and 13 applied equally large, in-phase voltages can be represented. Each connection is located here at the same potential, and no currents flow in the inductors 21, 22 or 23 of the circuit configuration 2. Instead, currents flow from each port through the corresponding individual ones Capacitors 24,25 or 26, and they add up through capacitor 28 to the ground plane. All capacitors therefore have an influence on the in-phase modes. Anyone who can do the opposite of the rotating modes are represented by voltages of the same magnitude applied to the three branches, which are 120 degrees from one another are out of phase. Therefore, in this case, currents flow in the inductances 21, 22 and 23 as well as in the Capacitors 24, 25 and 26. The total current in the capacitor 28 is because of the mutual 120 degree phase

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shift of the individual currents 0. The capacitor 28 thus has no influence on the oppositely rotating modes and can therefore only be used for tuning in-phase modes can be used.

Fig. 3 shows that for the in-phase modes in which no currents through the inductances 21 »22 and 23 flow, capacitors 31, 32 and 33 can be connected in series with inductors 21, 22 or 23 ", to create an exclusive control or »setting for the oppositely rotating modes. Therefore form these series capacitors in effect the counterpart to the parallel capacitor 28 for the; rotation modes. A double tuning known for the widening of the operating band of the circulator can thereby be achieved be that an inductance is additionally connected in parallel or in series with the capacitor 28 to exclusively to resonate with the in-phase modes. Similarly, inductors can serve the same purpose be connected in parallel to the capacitors 31, 32 and 33, which are only used in the opposite case rotating modes come into resonance.

The single parallel capacitor, e.g. 24, 25 or 26, in the embodiment according to FIG 4 enlarged and / or adjusted separately. Corresponding components of the circuit are in

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FIG. 4 is denoted by the same reference numerals as in FIG. The modification is that one conductive tab or a conductive strip 40 is conductively connected to the band 13 in such a way that it or he runs vertically along the edge of the core 14 and then on the underside of the core 14 parallel to the Band 13 is turned over on the top. An additional spacer made of dielectric material 41 is also provided between the tab 4o and the intermediate plane 16. Similar tabs are on the others Branches 11 and 12 are provided. The capacity between the intermediate level 16 and an individual Branch 11, 12 or 13 is determined by the length of the tab and by the thickness and dielectric constant of the spacer or piece 41 is determined. Note that the three are arranged in this way Tabs can be extended over a large area of the underside of the core 14, so far that they just don't touch.

Figures 5, 6, 7 and 8 show alternative strip line arrangements, whose electrical behavior is generally similar to the ring arrangement according to FIG. In Fig. the bands, e.g. 51, are straight strips that connect the vertices of the triangles to one another. Fig. 6 shows that a band, e.g. 5 2, inwards towards the

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central axis of symmetry can be curved. Fig. 7 shows an embodiment in which series capacitors (ζ.B "31, 32 and 33 according to FIG. 3) by band gaps or columns 53 and 54 are formed, which together one of these series capacitors electrically correspond. A single capacitive gap could appear in the middle of each belt, or the total capacitance at one end of the strip in the through the gap 55 in Fig. 8 indicated Much se arranged be. A larger capacity at one of these locations can be achieved with the help of an isolated overlap between at the ends of a given tape.

The principles of the present invention should not to be confused with those of arrangements known under the term "ring circulators", which in schematic form only have a superficial resemblance to the circulators claimed here. These known designs comprise three T-connections, which by nonreciproke; Phase shifter to a ring are affiliated. These known designs are large compared to a wavelength of the operating frequency and do not include concentrated constant resonance.

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Claims (3)

Claims 1.] Strip circuit circulator in delta connection with at least one ground plane and a strip line arrangement lying above the ground plane, the three rotationally symmetrical Ribbon line branches arranged around a central axis and one of these branches one after the other in has a series loop connecting conductive tape, further with a core made of gyromagnetic material, which is arranged on the central axis and couples the sections of the conductive tape together, when one of the branches is excited by high frequency wave energy relative to the ground plane, characterized in that a capacitance (24, 25, 26) between the ribbon line arrangement (11 to 13, 15, 21 to 23) and one between the ribbon line arrangement and the ground plane (17) lying intermediate point (16, 27) and a further capacitance (28) between the intermediate point (16, 27) and the ground plane are switched on. 2. strip line circulator according to claim 1, characterized in that that the capacitance (24, 25, 26) between the ribbon line arrangement (11 to 13, 15, 21 to 23) 309811/07 4 0 and the intermediate point (16, 27) by one to one Branch (11 to 13) of the strip line arrangement (11 to 13, 15) connected conductive tab is formed which at least part of the gyromagnetic core (14) on which the sections of the conductive connecting tape (15) overlaps the opposite side of the coupling surface and at a distance from a conductive part (16) is arranged at the intermediate point (27). 3. strip line circulator according to claim 1 or 2, characterized characterized in that the conductive tape (15, 51, 52) connecting the branches (11, 12, 13) by gaps (53, 54, 55) is divided into sections in order to tune oppositely rotating modes of the circulator series capacitances (31, 32, 33) to be introduced. 309811/07 40