FI121516B - directional Couplers - Google Patents

Description

The directional coupler

The invention relates to an embodiment of a directional switch for use in radio frequency circuits.

A directional switch is a measuring device that provides a signal proportional to the intensity of an electromagnetic field traveling in a given direction on a transmission path. In the transmission path 5, the field advancing in the opposite direction does not in principle affect the magnitude of said signal. The directional switch has at least three ports: The energy entering the input port is directed almost entirely through the switch to the output port, and a small amount of this energy is transferred to the third port, or gauge port. The part of the directional switch between the input and output ports is also part of the transmission path of the radio device extending, for example, to the transmitter antenna. The measuring port then provides a measuring signal proportional to the actual strength of the field propagating towards the antenna, which can be used for control purposes of the transmitter. If the directional switch is coupled to the transmission path, the measuring port provides a measuring signal proportional to the strength of the reflected field of the antenna, which can also be used for transmitter control purposes. The accuracy of the adjustments depends partly on the goodness of the directional switch, ie, how precisely the effect of the field going in the opposite direction to the field being measured is eliminated.

A simple directional switch can be formed on the circuit board by means of conductive strips. Figure 1 shows an example of such a known directional switch. The bottom surface of the PCB PCB 20 is a conductive signaling country GND. The top surface of the plate has a direct first J1 conductor strip 110, the initial end of which, together with the conductor patch connected to the signal ground, forms a directional switch input port P1. Correspondingly, the end of the first conductor strip together with the signal ground forms the direction switch output port P2. In addition, the top surface of the plate PCB has a second conductor strip 120 parallel to the first conductor strip 25 having a length of λ a quarter at the operating frequencies of the directional coupler. The distance between the conductor strips 110 and 120 is, for example, one tenth of their distance from the ground. The second conductor strip 120 extends away from its ends from the first conductor strip. The first extension 121 ends at measuring port P3. When the directional switch is in use, a measuring circuit is provided with a circuit 30 having an impedance Z equal to the characteristic impedance Z0 of the transmission lines formed by the directional switch conductor strips together with the signal ground and the medium. The second extension 122 of the second conductor strip terminates at the fourth port P4. Thus, the directional switch in the example has four ports, as with most other directional switches.

Due to the electromagnetic coupling between the first and second conductor strips, some of the energy supplied to the input port is transferred to the second conductor strip, the load impedances of the gates P3 2 and P4. When the frequency of the incoming field is such that the aforementioned λ / 4 condition, shown in Figure 1, is met, the energy transmitted to measuring port P3 is at its maximum and energy to the fourth port P4, the insulating port, is at its lowest. The latter energy is zero in the ideal switch because the even and odd waveforms present in the switch 5 cancel each other over the transmission line based on the second conductor strip 120 at the insulation end. This is the basis for the direction difference of the switch in question. Namely, if a field of the same frequency propagates from the output port to the input port, due to its symmetrical structure, its energy is not transferred to measuring gate P3 at all. The goodness of the direction difference il-10 is measured as the ratio of the signal level of the gate to the signal level of the isolation port. This is the same as the ratio of the level of the signal from the input port to the output gauge to the gauge port of the output port to the level of the signal from the gate to the gate when the opposite directions are of the same frequency and intensity.

A disadvantage of the structures of Figure 1 is the relatively poor directional separation. This is because the odd and odd waveforms do not completely cancel each other on the insulating port side, since the odd waveform propagates to a greater extent not only in the dielectric medium but also in the air, resulting in a higher velocity. A better orientation resolution is obtained if both conductor strips are arranged inside 20 dielectric plates having a ground plane on both sides. Another cure known from US 6549089 is to suitably increase the inductance between both first and second conductor strips and ground. This can be done, for example, with short-circuited transmission line branches shorter than a quarter-wave. However, all conductor strip-based directional switches have the drawback. only in a relatively small frequency range, an example of this is shown in Figure 2, which has two transmittance coefficients as a function of frequency, Graph 21 shows the change in signal level of the gate relative to the input signal level, and Graph 22 shows change in signal level of the isolation port relative to the input signal level. The graphs show that the direction difference is at most about 20 dB, but this value is only valid in the relatively narrow frequency range, but the 10 dB direction difference exceeds 1.8 - 2.45 GHz, nka has a relative width of 30%. Figure 21 further shows that, within the operating range of the directional switch, the signal level at the measuring port is about 25 dB lower than the signal passing through the switch, i.e., 35 dB. This means that the switch will cause a 0.014 dB attenuation of the through signal.

3

Figure 3 illustrates a known directional switching structure in which coupling to a signal transmission path is effected by means of point probes. The transmission path is a coaxial cable comprising an inner conductor 311 and a jacketed outer conductor 312. The outer conductor is shown in the figure cut open at a directional switch arrangement. There are two probes, the first 5 321 and the second 322 probes. They extend through the outer conductor 312 of the coaxial conductor into a space between the outer conductor and the inner conductor where the electromagnetic field containing the energy of the signal propagates. The distance between the probes is a quarter of the wavelength of the field at the operating frequencies of the directional switch. A first probe 321 is connected to a conduit 330 and a second probe 322 is connected to a second conduit 340. Throughout this description and claims the term "probe" is used. At the end, the test leads are galvanically connected and the interface forms a measuring port P3. There is no insulation gate in this structure. In this embodiment, the first measuring line 330 is half-wavelength and the second measuring line 340 is one-quarter wavelength. The second measuring line is terminated at the 15-side end of the probe with a 50 ohm resistor. The first measurement line does not interfere with this arrangement because it appears in the measuring port as a parallel resonance circuit, i.e., a very high impedance. In Figure 3, the direction of the signal is marked so that, as it progresses, it first reaches the first probe 321 and then the second probe 322. In this case, the fields passing through the probes and measuring leads are phase-aligned and thus reinforce each other. If there is a field in the opposite direction in the coaxial line, the parts branching from it to the probe will be in opposite directions in the measuring port, thus theoretically canceling each other. In this way, the structure acts as a directional switch. However, it also has the disadvantage that a good direction difference exists only in a relatively narrow frequency range. Similarly, good reflection attenuation from the 25 input side of the signal exists only in the relatively narrow frequency range.

The object of the invention is to reduce the above-mentioned disadvantages associated with the prior art. The directional switch according to the invention is characterized in what is disclosed in the independent claim 1. Certain preferred embodiments of the invention are set forth in the other claims.

The basic idea of the invention is as follows: The signal transmission path to be measured is connected at one point via a measuring line. The terminating resistor of the measuring line is placed in the field of the signal to be measured so that it acts as a part of the field strength sensing probe. In addition, the probe has a conductive surface which is within the second conductor 35 of the measuring line and is located in the direction of the signal to be measured relative to the resistor. The direction difference is based on such an asymmetric gauge structure. The outer end of the metered line viewed from the transmission line acts as the measuring port of the thus formed 4-way line switch.

An advantage of the invention is that the frequency dependence of the directional switch according to it is low: Good direction difference is achieved and the level of the measurement signal relative to the level of the signal 5 being measured is relatively constant over a very wide frequency range. Also, the reflector damping of the directional switch input port is high over a very wide frequency range. A further advantage of the invention is that the directional switch according to it is compact and can be implemented at a relatively low cost in connection with another component.

The invention will now be described in detail. Reference is made to the accompanying drawings, in which Figure 1 illustrates an example of a prior art directional switch, Figure 2 illustrates an example of a prior art directional switch, Figure 3 shows another example of a prior art directional switch, Figure 4 illustrates the principle of a directional switch a directional switch, Fig. 6 shows another example of a directional switch according to the invention, Fig. 7 shows an example of a coaxial structural part of a signal transmission path containing a directional switch according to the invention, Fig. 8 shows an example of a directional switch according to the invention Figure 10 shows a third example of a directional switch according to the invention in Figure 7. Fig. 11 shows an example of the direction difference of the directional switches of the invention, and Fig. 12 shows an example of the effect of the invention on the reflection factor of the directional switch,

Figures 1, 2 and 3 were already described in connection with the description of the prior art.

5

Fig. 4 is a conceptual representation of a directional switch according to the invention. It shows the transmission path determined by the conductors 411 and 412. The former conductor 411 is called the middle conductor and the latter conductor 412 is ground conductor according to the commonly used structure. However, the "center conductor" need not be located exactly in the middle of any transmission structure 5. Naturally, the term "earth conductor" comes from the fact that the conductor in question is usually coupled to a signal ground, or ground GND, as shown in Figure 3. The electromagnetic field EMF of the signal being measured propagates from input port P1 to output port P2. The structure further comprises a measuring line extending over the transmission path, comprising a first measuring line 421 and a second measuring line 422 10. The outer end of the test cable serves as the measuring port P3 for the directional switch. A resistor 425 is connected to the transmission line side end of the measuring line, the first end of the resistor to the first measuring line 421 and the second end to the second measuring line 422. These connections are galvanic in figure 4 but can also be capacitive if galvanic separation is required. The resistance R is equal to sa-15 than the specific impedance Z0 of the measuring line, for example 50Ω. The resistor thus acts as the end resistor of the measuring line in a manner known per se. According to the invention, the resistor 425 is located on the transmission path within the field of action of the EMF field, whereby it also functions as part of the signal strength sensing probe. The probe further comprises a sensor conductor 424 coupled to the first end 20 of the resistor 425 and a first measuring conductor 421. Thus, the sensor conductor is structurally associated with the first measuring conductor. The overall dimension of the probe in any direction shall be at least an order less than a quarter of the wavelength of the field to be measured.

The sensor conductor 424 has a certain conductor surface facing the transmission path, which is not present in the second measuring conductor extending from one end of the resistor 25. The conductor surface is adjacent to the resistor closer to the input port P1 than the resistor. It is essential that the center of gravity, i.e. the center of the aforementioned conductor surface, is located closer to the input port than the center of the resistor. Such asymmetry is based on the direction difference in the directional switch according to the invention. A 30 TEM (Transverse ElectroMagnetie wave) field propagating from the input port to the output port generates an alternating voltage proportional to the field strength of the measuring port P3, and energy is transferred to the impedance that loads the measuring port. Instead, energy is transferred from the field moving from the output port to the input port into the resistive mass of the resistor 425, but not much toward the gate. The achievable direction-35 resolution is good and does not even require a specific frequency, as in the known directional switches.

6

Figure 5 shows an example of a practical directional switch according to the invention. The directional switch is formed on a circuit board, such as the switch in Figure 1. The PCB in this example is a multilayer board. One intermediate layer has a direct first conductor strip 511, i.e. a middle conductor of the transmission line, and a strip 512 of the ground GND 5, which is parallel thereto. In addition to the paint strip 512, the earth conductor of the transmission path comprises a conductive lower surface, or ground plane, of the circuit board. Thus, the transmission path between the directional switch input port P1 and the output port P2 consists of a first conductor strip 511, partially enclosed therewith, and a dielectric ma-10 material on the circuit board. On the upper surface of the plate PCB, there is a fire resistor 525 in the direction of the transfer path above the first conductive strip 511 and the paint strip 512. The first end of the resistor on the input port P1 is connected to the first strip conductor 521 and the second end of the resistor on the output port to the second strip conductor 522. The measuring lead formed by the conductors leads to the measuring gate P3 of the directional switch 15. The resistor 525 on the transmission path serves as the terminating resistor of the measuring line and as part of the probe sensing the intensity of the electromagnetic field propagating on the transmission path. The second essential part of the probe consists of a tactile conduit 524 which is an extension of the first probe next to the first end of the resistor.

Figure 6 shows another example of a practical directional switch according to the invention. The directional switch is formed on the multilayer circuit board PCB in the same manner as in Figure 5. The difference with the switch in Figure 5 is that the resistor 625, which is part of the probe, is now transverse to the transmission path, on it. The other essential part of the probe, i.e. the sensing conduit 624, is for the most part adjacent to the resistor, on the input port P1. According to the invention, the sensor cable is connected to the first end of the resistor, so that it extends in the direction of the transmission line to the resistor. However, the center of gravity is clearly closer to the input port than the center of the resistor. Another difference with the switch of Fig. 5 is that the other end of the resistor 625 is directly connected to the ground plane by a bushing. In this case, the second ground conductor is the signal ground on the lower surface of the circuit board.

5 and 6, of course, the circuit board may also be single-layer. The probe can then be raised above the top surface of the circuit board, for example, by means of a small additional dielectric board.

Figure 7 shows an example of a signal transmission component which includes a directional switch according to the invention. The component is a cylindrical body, for example a coaxial connector. It has a center conductor, not shown in this figure, and a relatively thick-walled outer conductor 712. The outer conductor is the earth conductor of the transmission path. It has a recess for a directional switch arrangement, which passes through a metering line 720 of the directional switch. The recess is covered by its cover 750, which has a lead-through for the metering line. The cover supports the test lead while serving as a part of the outer conductor. The signal to be measured is applied to the I-5 structural member by a coaxial conductor 705 having a conductive sheath connected to an outer conductor 712 and an inner conductor to said center conductor. Figure 7 further shows an extended extension 713 of the outer conductor which, for example, is against a planar surface in the finished product.

Fig. 8 is an example of a directional switch according to the invention in a coaxial structure similar to that shown in Fig. 7. The structure is shown in cross section showing the signal path not only the outer conductor 812 but also the center conductor 811. From the point of view of the directional switch, the left end of the structure in Figure 8 serves as input port P1 and the right end as output port P2. At the bottom of the recess 830 in the outer conductor is a small circuit board 860. The outer surface of this circuit board has a probe according to the invention having a resistor 825 and a probe 824. The aperture base has an aperture 831 opening into the transmission cavity. The electromagnetic field propagating in the cavity is thus exposed to the probe. The coaxial measuring line 820 extends into the recess through this lead-through on the cover 850. The inner conductor 821, i.e. the first measuring conductor 821, of the measuring line is connected via the tactile line 824 to the first end, i.e. the input port side, of the resistor, and the conductive sheath 822, i.e. the second measuring line. These connections are shown in the accompanying figure, which shows the circuit board 860 from above. The sensor conductor 824 is a conductive strip of suitable size adjacent the first end of the resistor. The other end of the resistor, on the other hand, is connected to another conductor strip 25 861 to which the measuring conductor sheath is attached. The second conductor strip 861, viewed from the cavity, is for the most part "darkened", i.e. outside the aperture 831, due to directional separation.

The probe of Fig. 8 may be modified, for example, as follows: A conductor terminal 824 is made through a lower surface of the circuit board 860, where a conductive surface bounded by the cavity of the transmission path is formed to extend the lead-through. The portion of the tactile conduit on the surface side of the upper 30 may then be correspondingly smaller.

Figure 9 is another example of a directional switch according to the invention in a coaxial structure such as that shown in Figure 7. The structure is shown in section with the exception of the measuring line 920. The transfer path includes an outer conductor 912 and a middle conductor 911. The structure is similar to that of Fig. 8, except that the probe 3525, which acts as a probe, is now on the underside of the circuit board 960, i.e. the surface facing the coaxial transmission path. The resistor is then located in the opening 931 in the bottom 8 of the outer conductor recess 930. The lower surface of the circuit board 960 also has a tactile guide strip 924. This is connected to the first end of the resistor 925, i.e. the input port P1, a second conductor strip 961, which in this example-5 cat is connected to the outer conductor 912 by a screw which presses the circuit board 960 against the bottom of the recess 930.

Another difference between the structures of Figs. 9 and 8 is that in Fig. 9, the conductor sheath of the measuring line is connected to the outer path of the transmission path via sleeve 951 and cover 950.

Figure 10 is a third example of a directional switch according to the invention in a coaxial structure such as that shown in Figure 10 7. The recess A30 of the outer conductor A12 is in this case a cylindrical hole from the outer surface of the outer conductor to the inner surface. In the center of the hole is a measuring pin A21 extending into the cavity of the transmission path, the lower end of which A24 acts as a tactile conductor. The dipstick is surrounded and supported by a dielectric mass filling the hole A30. The resistor A25 belonging to the probe is the first end 15 connected to the probe and the other end connected to the inner surface of the outer conductor A12 in the cavity of the transmission path. The resistor is located at one end of the measuring surface parallel to the transmission path, viewed from the direction switch output port P2. Hole A30 is covered with conductive cover A50, except for the lead-through, to prevent leakage of high frequency electromagnetic field. Of course, a small portion of the energy of the field traveling on the transmission path is deliberately fed to the measuring switch P3 of the directional coupler by the measuring conductor A20, which includes the extension conductor A21 and another measuring conductor connected to the outer conductor. The test lead may be a coaxial conductor such that the probe is part of its inner conductor and the dielectric mass filling the hole A30 is part of the insulating mass between the inner conductor of the test lead and the jacket. In this case, the sheath may also extend to the bottom edge of the hole, and the other end 25 of the resistor A25 may be coupled to the sheath instead of the earth conductor.

Figure 11 shows an example of the features of directional switches according to the invention. Graph B1 shows as a function of frequency the change in the signal level of the measuring gate relative to the input signal level in the directional switches of Figures 8 and 10; both give the same result. Graph B2 shows the change in frequency as a function of signal level of the gate relative to the level of the signal going from the output port to the input port in Fig. 8, and graph B3 to the signal level of the gate to the input port in the directional switch. (The gray areas of graphs B2 and B3 exhibit relatively dense variation as a function of frequency.) 35 Graph B1 corresponds to graph 21 in Figure 2, and graphs B2 and B3 in graph 2 in Figure 2 22. Thus, the difference in decibels expresses the value of direction difference.

The graphs show that the direction difference is good over a very large frequency range. The improvement over the prior art shown in Figure 2 is very significant. With the directional switch of Fig. 8, the direction difference exceeds 20 dB in the range of about 1-4 GHz. With the directional switch of Fig. 10, the corresponding range is about 0.2-3 GHz. For example, in the range 1.8 to 1.9 GHz, the direction difference is about 28 dB with the switch in Figure 8 and about 23 dB with the switch in Figure 10.

In addition, graph B1 shows that, for example, at about 2GHz, the signal level in the mit-10 port is about 40 dB lower than the signal passing through the switch. This means that the measurement signal causes only 0.0003 dB attenuation to the transmitted signal.

Fig. 12 is another example of the features of a directional switch according to the invention. Graph C1 shows as a function of frequency the reflection coefficient of the input port in the directional switch shown in Figure 15-10. The switch of Fig. 8 gives essentially the same result, although in the range of 0.5-1.5 GHz and 3-3.5 GHz its reflection coefficient is about 10 dB worse. For comparison, graph C2 shows the reflection coefficient of the input port in a known quarter-wave directional switch. It will be appreciated that the directional switch of the invention also achieves good reflection damping in a very large frequency range. The reflection coefficient is about -30 dB or less from zero frequency up to 3 GHz, after which it decreases to about -20 dB up to 5 GHz. In the prior art directional switch, the reflection coefficient is at best about -30 dB. However, it falls below -20 dB only in the frequency range of 1.95-2.2 GHz, which is 12% relative bandwidth.

The attributes "lower" and "upper" refer to the position of the directional switch shown in Figures 5-10 and have no relation to the operating position of the devices.

The directional switch structures according to the invention have been described above. The implementation of these may differ in their details. The probe resistor 30 may be not only a combustion resistor, but also, for example, a carbon film resistor, a thin film resistor or a thick film resistor, and its resistance may vary. The inventive idea may be charged differently within the limits set by the independent claim 1.

Claims (15)

A directional switch having a input port (P1), an output port (P2), a measuring port (P3), a center conductor (411; 511; 611; 811; 911; A11) and a ground conductor (412; 512; 612; 712; 812; 912; A12) comprising a transmission line for conducting a signal to be measured from the input port to an output port, and a measurement line (620; 720; 820; 920) associated with the first (421; 521; 621; 821; 921; A21) and second (422; 522) measuring lines. ) for supplying a measuring signal to a measuring port terminated at its end on the transmission side by a resistor (425; 525; 625; 825; 925; A25) with the first measuring line connected to the first end of the resistor and the second measuring line connected to the other end the transmission path being coupled for measurement only at one point to the probe comprising said resistor bounded by a field propagation space of the signal to be measured and a sensor (424; 524; 624; 824; 924; A24), which sensor belongs to the first dimension. to the conductor and its center of gravity is closer to the input port (P1) than the resistor's center of gravity to perform directional to-15. 2. Riktkopplare i enlighet med patentkrav 1, a cantilever av att dess Överfö-ringaxis coaxial, stem jordledare (712; 812; 912; A12) innefattar en nisch (830; 930; A30), som börjar pä ytre ytan och som öppnar s. i häligheten av överfö- ringrägen, för placering av sensorledningen (824; 924; A24) och resistorn (825; 925; A25) tærverörörvågen, att electromagnetic förtet som utbreder i häligheten violated mot dem. Directional switch according to claim 1, characterized in that its transmission path is coaxial, the earth conductor (712; 812; 912; A12) having a recess (830; 930; A24) extending from the outer surface and opening into the cavity of the transmission path. and for positioning a resistor (825; 925; A25) on the transmission path so as to be exposed to the propagating electromagnetic field in the cavity. 3. Riktkopplare i enlighet med patentkrav 2, a rotation encoder nietnd nisch innefattar et kretskort (860; 960), a lightning resistorn and installerad and 20 ledande band atning a lightning bildar sensorledningen ätminstone delvis. Directional switch according to Claim 2, characterized in that it comprises, in said recess, a small printed circuit board (860; 960) on which the resistor is mounted and on which a conductor strip at least partially forms a tactile conductor. The transducer of the patent patent 3, the encoder of the att sensor sensor (824) and the resistor (825) of the present invention (860), the device (831) of the nischens (830) botten. Directional switch according to Claim 3, characterized in that the tactile conductor 25 (824) and the resistor (825) are on the upper surface of said circuit board (860) at an opening (831) at the bottom of the recess (830). 5. The transducer (3), the encoder of the att sensor sensor-25, and (924) and the resistor (925), respectively, of said crimp card (960), the node (931) and the nischens (930) botten. Directional switch according to claim 3, characterized in that the sensing conductor (924) and the resistor (925) are on the underside of said circuit board (960) in an opening (931) at the bottom of the recess (930). 6. Riktkopplare i enlighet med patentkrav 2, a transcript of a view of the nischen (A30) finns en mätningspin (A21), som sträcker sig i överfö- ringvägens hälighet, och som är en del av första mätningsledningen och är. 30 första ändan av den nämnda resistorn (A25) frän sin nedre ända. Directional switch according to claim 2, characterized in that in the center of said recess (A30) there is a measuring pin (A21) extending into the cavity of the transmission path, which is part of the first measuring conductor and is connected at its lower end to the first end. 7. The transducer and the magnification med patentkrav 6, the transducer node av attedre nän (A24), and the transducer image sensorledningen. Directional switch according to Claim 6, characterized in that the lower end (A24) of the measuring surface forms said tactile conductor, 8. Riktkopplare i enlighet med patentkrav 6, a stump deck and an att resistra (A25) and a kopplad i jordledaren (A12) av överföringsvägen. Directional switch according to Claim 6, characterized in that one end of the resistor (A25) is connected to the earth conductor (A12) of the transmission path. 9. Riktkopplare i enlighet med patentkrav 6, i wagering mätningsledningen en coax-och dess mantle sträcker sig till Nivan av den nischens nedre kant, 5 turnbuckle av att andra ändan av resistorn är kopplin i mätningsledningen. A directional switch according to claim 6, wherein the measuring line is coaxial and its sheath extends to the lower edge of said recess, characterized in that one end of the resistor is connected to the measuring line sheath. 10. Riktkopplare i enlighet med patentkrav 6, a rotary encoder av attrymmet av nischen (A30) som omger mätningspinnen (A21), and a stencil delvis fylld med dielektriskt stödämne. Directional switch according to claim 6, characterized in that the space of the recess (A30) surrounding the measuring pins (A21) is at least partially filled with a dielectric support 10. 11. A ratchet of magnification med patent krav 2, the codenamed av att den nischen nickname (750; 850; 950; A50). A directional switch according to claim 2, characterized in that said recess is covered by a conductive cover (750; 850; 950; A50). 12. The patent application of the patent application No. 1, the telecommuting protocol (511; 611), the data transfer card (PCB) and the encoder encoder (GND), The (524; 624) and resistor (525; 625) ligger are overexpression rings. A directional switch according to claim 1, characterized in that the middle conductor of its transmission path is a conductor strip (511; 611) belonging to the circuit board (PCB) and the ground conductor 15 comprises at least a ground plane (GND) of the circuit board; 625) are located above the data link. 13. Riktkopplare i enlighet med patentkrav 12, a transducer ng av att mellanleda-ren av överföringsvägen ligger i mellanlagret av kretskortet, och sensorledningen and resistorn ligger pä Övre ytan av kretskortet. A directional switch according to claim 12, characterized in that the middle conductor of the transmission path is in the intermediate layer of the circuit board, and the sensing conductor and the resistor are on the upper surface of the circuit board. 14. Riktkopplare i enlighet med patentkrav 12, kännetecknad av att mellanledaaren av överföringsvägen ligger nap Övre ytan av kretskortet och sensorledningen och resistorn ligger oven kretskortets övre yta, separerade frän övre ytan med ett dielektriskt lager. A directional switch according to claim 12, characterized in that the middle conductor of the transmission path is on the upper surface of the printed circuit board, and the sensing conductor and the resistor are above the upper surface of the printed circuit board separated by a dielectric layer. A directional switch according to claim 1, characterized in that said resistor is one of the following: burn resistance, thin film resistor, thick film resistor, carbon film resistor. > 1. Riktkopplare, som innefattar en ingängsport (P1), en utgängsport (P2), en mätningsport (P3), en överföringsväg som innefattar en mellanledare (411; 511; 611; 811; 911; A11) och jordledare (412; 512) ; 612; 712; 812; 912; A12), för led-30 Ning av signalen som dir frän ingängsporten account utgängsporten, samt en mät-ningsledning (620; 720; 820; 920), som kopplas i överföringsvägen och som innefattar en första mätningsledning (421; 521; 621; 821; 921; A21) och en andra mät-ningsledning (422; 522), för ledning av mätningssignalen i mätningsporten, wien mätningsledning änds med en resistor (425; 525; 625; 825; 925; A25) i sin a mot överföringsvägen ä, att första mätningsledning är kopplad i första ändan av 5 resistorn och andra mätningsledning i andra ändan av resistorn, kännetecknad av attför mätning kopplas i överföringsvägen enbart innefattar den nämnda resistorn och en sensorledning (424; 524 ; 624; 824; 924; A24), som begränsas i utbredningsutrymmet av fältet av mätad signal, vilken sensorledning hör i första mätningsledningen och dess tyngdpunkt ligger 10 närmare ingängsporten (P1) än resistorns tyngdpunkt, förningsering av. 15. Riktkopplare i enlighet med patentkrav 1, kennnetecknad av att nämnd resis-25 Tor är en av feljande: hybrid motor, tunnel film resistor, tjock film resistor, kolfilms resistor.