KR100766875B1 - Ring-hybrid type directional coupler using folded line structure having low pass filter characteristic - Google Patents

Abstract

A ring-hybrid directional combiner of a folded structure having LPF(Low Pass Filter) property is provided to reduce the size of the combiner by compounding an LPF of electric length of 1/4 lambda in an equivalence circuit. A ring-hybrid directional combiner of a folded structure having LPF property includes a substrate and first or sixth microstrip railway line units(21,26). The substrate is made of an insulating material. The first or sixth microstrip railway line units(21,26) is generally arranged in a shape of a ring and has first and second transmission railway lines(11,12), an LPF block(13). The first and second transmission railway lines(11,12) with electric length of l/4 lambda are generally arranged on the substrate in a shape of an arc. The LPF block(13) is connected to the first and second transmission railway lines(11,12) and are arranged toward the center of the combiner. A first output port(2), an input port(1), a second output port(3), and an isolation port(4) are arranged in a radial shape with an angle of 60 degrees on a standard of the center of the combiner.

Description

Ring-Hybrid Type Directional Coupler Using Folded Line Structure Having Low Pass Filter Characteristic}

1 and 2 illustrate a typical ring-hybrid directional coupler structure and properties, respectively;

3 illustrates a low pass filter (LPF) structure having a coupling line including an open stub between two transmission lines and an equivalent circuit thereof for use in the first embodiment according to the present invention;

4 is a diagram illustrating a characteristic curve of a low pass filter using the coupling line shown in FIG. 3;

5 is an exemplary structure diagram of a ring-hybrid directional coupler having a low pass filter having an electrical length of λ / 4 according to the first embodiment of the present invention;

FIG. 6 is an exemplary physical comparison example of a ring-hybrid directional coupler with a folded structure having a low pass filter characteristic implemented according to a first embodiment of the present invention;

7 is a diagram illustrating a simulation characteristic graph of the directional coupler according to the present invention shown in FIG.

8 is an exemplary view illustrating an EM simulation characteristic of the directional coupler according to the present invention;

9 to 12 are exemplary views showing the measurement results of the performance of the ring-hybrid directional coupler actually manufactured according to the first embodiment of the present invention,

FIG. 13 is a configuration diagram of a microstrip line unit using a pair of low pass filters (LPFs) whose total length is set to λ / 4 for use in the second embodiment according to the present invention.

14A and 14B show a simplified structure of FIG. 14A and a ring-hybrid directional coupler having a lowpass filter according to a second embodiment of the present invention implemented using the microstrip line unit designed in FIG. Example,

FIG. 15 is an exemplary graph illustrating simulation characteristics of a directional coupler circuit having the broadband stop characteristic shown in FIG. 14B;

FIG. 16 is an exemplary diagram showing a ring-hybrid directional coupler having a structure using a coupled line implemented according to the present invention in comparison with a conventional directional coupler; FIG.

17 is a graph illustrating an EM simulation result of the hybrid directional coupler illustrated in FIG. 16.

18 to 21 are exemplary views showing measurement results of the performance of the ring-hybrid directional coupler actually manufactured according to the second embodiment of the present invention.

* Explanation of Signs of Major Parts of Drawings *

1: input port 2, 3: output port

4: isolation port

11, 12, 30, 51, 52: Transmission line 13a, 13b, 32a, 32b, 53a-53c: Combined line

13c, 31, 53d: open stub 13, 33a, 33b, 53: LPF block

21-26,40-46,61-66: Microstrip track units

The present invention relates to a directional coupler for use in microwave or millimeter bands. In particular, the ring structure of a ring hybrid is reduced by using a coupling line and an open stub of a folded structure having low pass filter (LPF) characteristics. In addition, the present invention relates to a ring-hybrid directional coupler with a folded structure having LPF properties that can improve harmonic rejection.

In general, high frequency and ultra high frequency fields are currently using a wider and higher frequency band due to the rapid development of mobile communication. As a result, the system becomes more complicated and the use of active devices such as mixers, amplifiers, oscillators, and diode switches increases, and the elimination of unwanted signals such as harmonics and intermodulation distortions generated by them has to be solved from the past. It is a fundamental problem to do, and these problems are getting worse due to the widening of the system.

In addition, the necessity of low cost, miniaturization, and complex functions of communication systems is now a challenge, and various methods have been researched and announced in order to find a breakthrough of such problems. Among them, representative examples of the directional coupler using the micro strip line include a quarter-wave parallel linear coupler, a quarter-wave branch line coupler, and a ring-hybrid directional coupler.

Briefly with reference to Figures 1 and 2 attached to the conventional ring-hybrid directional coupler structure and characteristics, the size of the ring in the ring-hybrid directional coupler based on the λ / 4 line as shown in Figure 1 attached Six λ / 4 is combined to have a length of 1.5λ, and the coupling band has a good coupling characteristic of 3dB, but the passband is regularly repeated at higher frequencies as shown in FIG.

That is, the frequency characteristic of the conventional ring-hybrid directional coupler is repeated harmonic characteristics at odd multiplication frequencies.

At this time, looking at the signal input and output relationship of the conventional ring-hybrid directional coupler, in the case of in-phase port 1 is the input port, port 2 and port 3 is the output port, the signal input through the port 1 is port 2 And is divided into in-phase components at port 3, and port 4 is isolated and port 4 is isolated. In addition, in the out-of phase, the signal input through the port 4 is divided into a phase difference of 180 degrees between the port 2 and the port 3, and the port 1 is isolated. In FIG. 1, reference numbers for respective ports are shown in original letters.

In such a ring coupler, characteristics such as power distribution ratio are determined by appropriately setting the length of the line connecting the four ports and the characteristic impedance of the line.

However, in the ring-type coupler, when the frequency of the signal to propagate increases to the millimeter wave band, the line length of the line connecting each port becomes shorter and the line width becomes relatively wider, making it difficult to form the line pattern on the substrate.

In addition, the microwave system will be affected by many factors, but as described above, the ability to effectively handle unwanted signals among the signals generated by nonlinearity of active elements is a decisive factor in system performance. Is one of.

In most cases, multiple filters are used in high frequency systems to eliminate or suppress these unwanted signals as much as possible. This additional circuit has the disadvantage that the size of the device increases and the loss increases. In addition, this method is difficult to implement several intentional attenuation poles at the same time, so it is limited to a wide stop band implementation method.

Moreover, a typical 3 kHz directional coupler in the low frequency band (general term for the directional coupler with gain of 3 dB in the area referred to as m1 in FIG. 2) has the disadvantage that the physical size is too large. Accordingly, methods for reducing the size by folding the track or adding an open stub have been studied. Since these methods are only designed to reduce the physical size of the directional coupler, there are problems in practical application.

An object of the present invention for solving the above problems is to configure the ring structure of the ring-hybrid using a coupling line and an open stub of the folded structure having the LPF characteristics can improve not only the size of the ring but also the harmonic rejection characteristics. It is to provide a ring-hybrid directional coupler of a folded structure having an LPF characteristic.

Another object of the present invention is to provide a ring-hybrid directional coupler with a folded structure that can not only significantly reduce the size but also block the repeating of the passband at three multiply frequencies without additional circuitry. have.

According to a first aspect of the present invention for achieving the above object, the present invention includes a substrate made of an insulating material; First and second transmission lines each having an electrical length λ / 4 on the substrate and arranged in an arc shape, and a low pass filter (LPF) block connected to the first and second transmission lines and disposed toward the center; First to sixth microstrip track units configured and arranged in an annular shape; A first output port, an input port, and a second end disposed radially at an angle of 60 degrees with respect to a center point connected between first and second transmission lines of the adjacent first to fifth microstrip line units, respectively; And a low pass filter (LPF) block of each of the first to sixth microstrip line units, one end of which is connected to and adjacent to the first and second transmission lines. 2 coupling lines and an open stub connected to the other ends of the first and second coupling lines, the opening stubs being sequentially equally bent so as to form an angle of 30 degrees between the first and second coupling lines, respectively. Ring-down structure with an LPF characteristic, characterized in that it extends radially toward the first output port, the input port, the second output port and the isolation port and towards the first and second transmission lines. Brides provide directional coupler.

In this case, each of the low pass filter LPF blocks is preferably set to have a cutoff frequency f _c higher than the frequency of the coupling band.

In addition, the first output port and the isolation port is disposed to form a 180 degree, and has an electrical length of 3λ / 4.

Furthermore, the substrate is preferably pentagonal.

According to a second aspect of the invention, the present invention provides a substrate comprising an insulating material; First and second transmission lines each having an electrical length λ / 4 on the substrate and arranged in an arc shape, and a low pass filter (LPF) block connected between the first and second transmission lines and disposed toward the center; A first to sixth microstrip line unit configured to be annularly arranged; The first output port, the input port, and the second output radially arranged with one end connected to the low pass filter (LPF) blocks of the adjacent first to fourth microstrip line units and arranged at an angle of 60 degrees with respect to the center point. And a low pass filter (LPF) block of each of the first to sixth microstrip line units, each having a first to third coupling line and one end to the other end of the first to third coupling line. A ring-hybrid directional coupler having a folded structure having an LPF characteristic, characterized in that it is connected and is composed of an open stub, the other end being bent toward the first or second transmission line and extending radially.

In this case, each of the low pass filter (LPF) blocks has one end connected to the first and second transmission lines, the first and second coupling lines disposed toward the center, and adjacent to each other, and one end of the first output port. And a third coupling line connected to one of an input port, a second output port, and an isolation port and disposed between the first and second coupling lines, and an open stub connected to the other ends of the first to third coupling lines. The open stub is bent such that the angle between the first to third coupling lines is 30 degrees and extends radially.

Further, each of the low pass filter (LPF) blocks is preferably set to have a cutoff frequency f _c higher than the frequency of the coupling band.

Moreover, each of the lowpass filter (LPF) blocks is set to a stopband to block at least three multiplied frequencies.

In addition, the first output port and the isolation port are disposed to form 180 degrees with an electrical length of 3λ / 4, and include the fifth and sixth microstrip line units.

According to a third aspect of the invention, there is provided a substrate comprising: a substrate made of an insulating material; First to sixth transmission lines each formed on the substrate with an electrical length λ / 4 and having an arc shape having an arc angle of 60 degrees and arranged in an annular shape as a whole; A first output port, an input port, a second output port, and an isolation port each having one end sequentially disposed at a connection point between the first to fifth transmission lines and the other end extending radially; One end is disposed at the connection point between the first to sixth transmission lines, and the other end is radially extended toward the center, and has a cutoff frequency higher than that of the coupling band and has a first to sixth low pass for blocking harmonics. First and sixth low pass filter (LPF) blocks each having one end connected to one of the first to sixth transmission lines and disposed adjacent to the center; A second coupling line, a third coupling line having one end connected to one of the first output port, the input port, the second output port, and the isolation port and disposed between the first and second coupling lines; LPF is characterized in that it consists of an open stub connected to the other end of the third coupling line and bent to form a 30 degree angle between the first to the third coupling line to extend radially Provided is a ring-hybrid directional coupler having a folded structure.

(Example)

The above objects and various advantages of the present invention will become more apparent from the preferred embodiments of the present invention described below with reference to the accompanying drawings by those skilled in the art.

First of all, the technical features of the present invention will be briefly described. In order to reduce the size of a device by folding a line or adding an open stub by using existing methods, the design method for reducing only the physical size of the directional coupler is practical. Therefore, the structure having the first and second coupling lines 13a and 13b including the open stub 13c between the first and second transmission lines 11 and 12 is generally as shown in FIG. It has the characteristics of low pass filter (LPF).

The amount of the LPF block 13 including the electrical length θ ₂ for the equivalent circuit of the LPF block 13 consisting of the first and second coupling lines 13a, 13b and the open stub 13c in the center of the structure. A pair of transmission lines (11, 12) of electrical length θ ₁ are connected to the side, and the electrical length for use in the directional coupler of f ₀ is λ / 4 (= 2 × θ ₁ + θ ₂ ), and also coupling It can be designed to be an LPF having a cutoff frequency f _c higher than the frequency of the band.

Therefore, each parameter of the T-type equivalent circuit in the LPF block 13 of FIG. 3 may be defined as Equation 1 below.

In Equation 1, Z _oe and Z _oo are impedances in even-odd-mode of the coupling line, θ _c is the physical length of the coupling line, and L _p and C _p are parameters of the T-type equivalent circuit of the coupling line. Where Y _s is the admittance of the open stub, θ _s is the length of the stub, and C _s is the equivalent circuit parameter.

The impedance Z _TL of the first and second transmission lines 11 and 12 and the impedance of the LPF block equivalent circuit use 70.7 Ω to be directly applied to the combiner, and the first and second transmission lines ( LPF designs with an electrical length of λ / 4 are possible, including an electrical length θ ₁ of 11,12).

In this case, the LPF should be designed so that the LPF has a cutoff frequency (f _c ) higher than the frequency of the coupling band so that the coupling frequency is not affected.

In the LPF block 13 having the cutoff frequency f _c using the circular element, the physical relationship between the coupling lines 13a and 13b and the open stub 13c is obtained by using the relationship between the T-type equivalent circuit and the general dispersion element. Parameters can be derived.

At this time, the characteristics of the LPF using the coupling line as shown in the accompanying Figure 4, the characteristics of the LPF improved harmonic rejection characteristics having a -3 kHz cut-off frequency f _c = 4 kHz higher than the coupling frequency of 2.45 kHz Got.

Physical parameters of the circuit simulation of the LPF having the above-mentioned wideband harmonic blocking characteristics are shown in Table 1 below.

70.7 Ω Line (mm) [Z _TL (θ ₁ )] Coupling Line (mm) Open stub (mm) Width: 0.729 Length: 3.81 Width: 0.14 Space: 0.17 Length: 5.69 Width1: 0.51 Length1: 2.165 Width2: 0.9793 Length2: 1.512 Substrate Specifications ε _r : 4.4, h: 0.762 mm, t: 38 μm, tan δ: 0.025

Therefore, the present invention induces and utilizes a low pass filter structure in the existing method of folding a line or adding an open stub proposed as a design method for reducing only the physical size of the directional coupler. It is conceived that by constructing using, it will not only significantly reduce the size but also block the repetition of the passband at the triplet frequency without additional circuitry.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail.

Based on the concept of Equation 1, the ABCD-matrix of the general transmission line TL may be defined as Equation 2 below.

In this case, the ABCD-matrix of the series inductor and the parallel capacitor in Equation 2 is expressed by Equations 3 and 4 below by reference to David M. Pozar, Microwave Engineering, John Wiley & Sons, Inc. 2005. Is defined as:

Accordingly, the ABCD-matrix for the T-type equivalent circuit in the LPF block 13 shown in FIG. 3 can be derived as shown in Equation 5 below using Equations 3 and 4.

Therefore, using the equations (2) to (5), the entire ABCD-matrix (T) of the λ / 4-length low pass filter (LPF) shown in FIG. 3 is defined. It can be defined as Equation 6.

Therefore, the parameters of the matrix for the low pass filter (LPF) having the electrical length λ / 4 have the same value as the ABCD parameter of the proposed structure and the λ / 4 line.

That is, as shown in the accompanying FIG. 5, the corresponding low-pass filters having the electrical length λ / 4 shown in FIG. 3 are respectively used to correspond to the λ / 4 line of FIG. 1 representing a conventional general ring directional coupler. The structure of the same bond group was obtained.

Referring to FIG. 5, the ring-hybrid directional couplers of the folded structure having the LPF characteristics according to the first embodiment of the present invention each have an overall electrical length λ / 4 as shown in FIG. 3, and a low pass filter ( LPF) block 13 and the first and second transmission line (11, 12), the first to sixth microstrip line unit (21-26) arranged in an annular shape, and the adjacent first to fifth A first output port 2 connected between the first and second transmission lines 11 and 12 of the microstrip line unit 21-25 and arranged at an angle of 60 degrees with respect to the center point, and disposed radially and connected at one end thereof. ), An input port (1), a second output port (3), and an isolation port (4).

That is, the second to fourth microstrip line units each having an electrical length λ / 4 between the first output port 2, the input port 1, the second output port 3, and the isolation port 4, respectively. 22-24 are arranged one by one, and between the first output port 2 and the isolation port 4, three microstrip line units corresponding to the electrical length 3λ / 4, that is, the first microstrip line unit 21 And fifth and sixth microstrip track units 25 and 26 are arranged.

In this case, the low pass filter (LPF) blocks 13 of the first to sixth microstrip line units 21 to 26 may include the first and second coupling lines 13a and 13b and the open stub ( 13c), wherein the open stub 13c is bent such that the angle between the first and second coupling lines 13a and 13b is about 30 degrees, respectively, in order to sequentially form the first output port 2, It extends radially toward the input port 1, the second output port 3 and the isolation port 4 and the transmission lines 11 and 12.

Further, the low pass filter (LPF) block 13 is preferably set to have a cutoff frequency f _c higher than the frequency of the coupling band.

The ring-hybrid directional coupler according to the present invention described above has an open stub 13c because the open stub 13c has no functional relationship even if it is folded if the area of the open stub 13c is electrically connected to the first and second coupling lines 13a and 13b. ) Can be formed into a folded structure.

The ring-hybrid directional coupler according to the present invention has an LPF characteristic and at the same time has an open stub (13c) is folded structure, as shown in Figure 6 when the physical implementation, as shown in Figure 6, 2.45㎓ 70.7Ω 4 The length is 17.355 mm but the linear length of the counterpart in the coupler of the present invention is reduced by about 55% to 7.8 mm.

In the present invention, a dielectric constant (ε _r ) of 4.4 and a substrate thickness (H) of 0.762 mm were fabricated using a FR-4 substrate, as shown on the left side of FIG. A directional coupler having a center frequency is shown, and it can be seen that the ring-area is greatly reduced to 25% compared to the conventional conventional coupler shown on the right side of FIG. 6.

Furthermore, referring to FIG. 7 attached to the simulation characteristics of the coupler according to the present invention shown in FIG. 5 described above, FIG. 7 shows broadband harmonic blocking characteristics that match the stop band of the low pass filter having an electrical length λ / 4. The circuit simulation characteristics of the directional coupler show that the coupling band shows the same power distribution, impedance matching, and isolation characteristics as the conventional coupler, and the harmonic stop band has good blocking characteristics of -20㏈ or less up to 11㎓. have.

8 is an EM simulation characteristic of the directional coupler according to the present invention.

In the results of the EM simulation, the coupling section has the same characteristics as the general coupler. However, the LPF block 13 converged toward the center of the circle, affecting the harmonic characteristics.

Therefore, the center frequency decreased from 2.45 2.4 to 2.41 하면서 as the length of the arc increased slightly during the optimization process and the conversion of the entire model to the harmonic stopband characteristics. The cutoff section shows good cut-off characteristics below -20kHz up to about 11 GHz. Ring-hybrid design parameters are shown in Table 2 below, which are the physical lengths of the couplers manufactured through the optimization process.

Radius of circle (mm) 70.7 Ω Line (mm) [Z _TL (θ ₁ )] Coupling Line (mm) Open stub (mm) 7.6 Width: 0.729 Length: 3.98 Width: 0.14 Space: 0.17 Length: 4.796 Width1: 0.51 Length1: 4.29 Width2: 1.35 Length2: 1.39

As described above, referring to FIGS. 9 to 12, the measurement results of the performance of the ring-hybrid actually manufactured according to the present invention will be described with reference to FIGS. 9 to 12. FIG. 9 is a diagram illustrating power distribution, impedance matching, and isolation of a coupling section. 10 and 11 show in-phase and inverse phase characteristics, and FIG. 12 shows good blocking characteristics of broadbands of -20 dB or less up to 11 dB including triplex harmonics in the harmonic region.

This actual test result shows a frequency characteristic which is generally similar to the simulation result (see FIG. 7) for the ring-hybrid directional coupler having a folded structure according to the first embodiment shown in FIG. 5. I can know that

That is, it can be seen that it has the same characteristics as the general ring-hybrid at the center frequency of 2.41 가지며 and has the stopping characteristic of -20 ㏈ or less up to 11 포함한 including the 3rd harmonic. Reduced to. In addition, it can be seen that the measured frequency characteristic results of the fabricated ring-hybrid are in good agreement with the circuit and EM simulation results.

In the first embodiment described above, LPF characteristics are realized by combining a pair of coupling lines and an open stub, whereas the total length is limited to a line having a length of λ / 4 by using two coupled lines. At the same time, a low pass filter having an excellent stop band can be obtained by attaching an open stub to each coupling line under the coupling size, which will be described in detail with reference to the accompanying drawings of FIG. 13 as a second embodiment of the present invention. Shall be.

13 shows a microstrip line unit having a total length set to [lambda] / 4 and using a pair of low pass filters (LPFs) for use in the second embodiment according to the present invention.

In the microstrip line unit 40 shown in FIG. 13, open stubs 31a and 31b are connected to one ends of the first and second coupling lines 32a and 32b, which are arranged in parallel and adjacent to each other, respectively. Excellent first and second low pass filter (LPF) blocks 33a, 33b. The first and second low pass filter (LPF) blocks 33a and 33b are interconnected by a transmission line 30, and the first and second low pass filter (LPF) blocks 33a and 33b and a transmission line. The total length of 30 is set to λ / 4.

Similar to the microstrip line units 21-26 of the first embodiment, the microstrip line unit 40 constitutes a low pass filter (LPF) having excellent stop band through the characteristic graph.

In addition, the microstrip line unit 40 shown in FIG. 13 can be applied directly to the directional coupler because the total length is? / 4.

When the microstrip line unit designed in FIG. 13 is used to correspond to the λ / 4 line of the general directional coupler, it may be implemented as shown in FIG. 14A.

14A and 14B show a simplified structure of FIG. 14A and a ring-hybrid directional coupler having a lowpass filter according to a second embodiment of the present invention implemented using the microstrip line unit designed in FIG. It is an illustration.

First, referring to FIG. 14A, a ring-hybrid directional coupler having a low pass filter in accordance with a second embodiment of the present invention has six first to sixth microstrip line units 41-46 designed in FIG. 13. By interconnecting them.

Since the directional coupler of the second embodiment shown in FIG. 14A includes twelve low pass filter (LPFs) 33a and 33b, the directional coupler may be modified as shown in FIG. It is possible. That is, when two low pass filters (LPFs) 33a and 33b are integrated into one, they are reconstituted into six low pass filters (LPFs).

As a result, the ring-hybrid directional coupler having the low pass filter according to the second embodiment of the invention shown in FIG. 14B is composed of the first to sixth microstrip line units 61 to 66, and the first to sixth. Each of the microstrip line units 61-66 includes first and second transmission lines 51 and 52 and first and second coupling lines 53a having one end connected to the first and second transmission lines 51 and 52. 53b, a third coupling line 53c connected to each of the ports 1-4, and an open stub 53d connected to the other ends of the first to third coupling lines 53a, 53b, and 53c. Consists of.

The first to third coupling lines 53a, 53b, and 53c and the open stub 53d together form a low pass filter (LPF) block 53, and the first to sixth microstrip line units 61-66. Each open stub 53d is bent such that the angle between the first to third coupling lines 53a to 53c is approximately 30 degrees, in the same manner as in the first embodiment, so that the transmission line 51, Extending radially toward 52).

In addition, the low pass filter (LPF) block 53 is preferably set to have a cutoff frequency (f _c ) higher than the frequency of the coupling band.

The ring-hybrid directional coupler according to the present invention described above has an open stub 53d since the open stub 53d has no functional relationship even if it is folded as long as it is electrically connected to the first to third coupling lines 53a to 53c. ) Can be formed into a folded structure.

As a result, the ring-hybrid directional coupler according to the present invention has an LPF characteristic and at the same time has an open stub 53d structure, which is physically implemented as shown in FIG. 16.

At this time, three ports are coupled to each of the ports 1-4, and the same characteristics can be obtained even with a simpler structure.

In addition, it can be seen that the stopband of the designed directional coupler is consistent with the stopband of the lowpass filter described above.

FIG. 15 shows simulation characteristics of the directional coupler circuit having the broadband stop characteristic shown in FIG. 14B. The coupling band shows the same characteristics as the general coupler, and the harmonic stop band characteristics are quite good. .

In addition, when the directional coupler circuit having the broadband stop characteristic shown in FIG. 14B is actually implemented, it may be implemented as shown on the left side of the accompanying FIG. 16, and the present invention illustrated in FIG. Compared with the first embodiment, it can be seen that they have the same size, and therefore, they are considerably reduced to 25% of the existing coupler size shown on the right side of FIG.

The EM simulation results of the ring-hybrid directional coupler shown in FIG. 15 are in good agreement with the measured frequency characteristic results of the fabricated ring-hybrid sample shown in FIG. 17, as shown in FIG. 17. The characteristics of the coupling and blocking sections are similar to those of the general coupler, and the center frequency is slightly lowered, but the blocking section shows a good blocking characteristic of -30 dB up to about 10 GHz.

18 to 21 are exemplary views showing measurement results of the performance of the ring-hybrid directional coupler actually manufactured according to the second embodiment of the present invention. FIG. 18 is a diagram illustrating power distribution, impedance matching, and 19 and 20 show in-phase and anti-phase characteristics, and FIG. 21 shows good blocking characteristics of broadbands of -20 dB or less up to 11 dB including triplex harmonics in the harmonic range. .

While the invention has been shown and described in connection with specific embodiments thereof, it is well known in the art that various modifications and changes can be made without departing from the spirit and scope of the invention as indicated by the claims. Anyone who owns it can easily find out.

As described above, the ring-hybrid directional coupler having the LPF characteristics according to the present invention combines the LPF of the electrical length λ / 4 in an equivalent circuit using a coupling line between each port to reduce the size of the coupler as well as the broadband. It also shows the harmonic blocking characteristics of, and it is possible to be completely matched and completely separated at the center frequency, and the area of the ring is reduced to 1/4 compared to the conventional one, and it is possible to reduce the harmonics below -20 Hz to 11 Hz including tripled harmonics. It has the effect of having excellent properties of blocking.

Claims (10)

A substrate made of an insulating material; First and second transmission lines each having an electrical length λ / 4 on the substrate and arranged in an arc shape, and a low pass filter (LPF) block connected to the first and second transmission lines and disposed toward the center; First to sixth microstrip track units configured and arranged in an annular shape; A first output port, an input port, and a second end disposed radially at an angle of 60 degrees with respect to a center point connected between first and second transmission lines of the adjacent first to fifth microstrip line units, respectively; Composed of output port and isolation port Each of the low pass filter (LPF) blocks of each of the first to sixth microstrip line units includes first and second coupling lines having one end connected to and adjacent to the first and second transmission lines, respectively. It is composed of an open stub connected to the other end of the second coupling line, The open stubs are sequentially bent such that the angle between the first and second coupling lines is equal to 30 degrees, respectively, so that the first output port, the input port, the second output port, and the isolation port and the first and second transmission lines A ring-hybrid directional coupler with a folded structure, characterized in that it extends radially towards. delete 2. The ring-hybrid directional coupler of claim 1, wherein the first output port and the isolation port are disposed to form 180 degrees, and have an electrical length of 3λ / 4. 2. The ring-hybrid directional coupler of claim 1, wherein the substrate is pentagonal. A substrate made of an insulating material; First and second transmission lines each having an electrical length λ / 4 on the substrate and arranged in an arc shape, and a low pass filter (LPF) block connected between the first and second transmission lines and disposed toward the center; A first to sixth microstrip line unit configured to be annularly arranged; The first output port, the input port, and the second output radially arranged with one end connected to the low pass filter (LPF) blocks of the adjacent first to fourth microstrip line units and arranged at an angle of 60 degrees with respect to the center point. Port and isolation port, Each of the low pass filter (LPF) blocks of the first to sixth microstrip line units has first to third coupling lines and one end connected to the other end of the first to third coupling lines, and the other end to the first or third coupling line. 2. A ring-hybrid directional coupler with an LPF characteristic, characterized in that it consists of an open stub that is bent toward the transmission line and extended radially. 6. The apparatus of claim 5, wherein the low pass filter (LPF) block comprises: first and second coupling lines, one end of which is connected to the first and second transmission lines and disposed toward and adjacent to the center; A third coupling line having one end connected to one of the first output port, the input port, the second output port, and the isolation port and disposed between the first and second coupling lines; An open stub connected to the other end of the first to third coupling lines, The open stub is a ring-hybrid directional coupler having an LPF characteristic, characterized in that the angle between the first to the third coupling line is bent to form a 30 degree radially extending. delete 6. The ring-hybrid directional coupler of claim 5, wherein the lowpass filter (LPF) blocks each have a stopband set to block at least three multiplied frequencies. The folded and having LPF characteristic according to claim 5, wherein the first output port and the isolation port are arranged to be 180 degrees with an electrical length of 3λ / 4, and include the fifth and sixth microstrip line units. Ring-hybrid directional coupler in structure. A substrate made of an insulating material; First to sixth transmission lines each formed on the substrate with an electrical length λ / 4 and having an arc shape having an arc angle of 60 degrees and arranged in an annular shape as a whole; A first output port, an input port, a second output port, and an isolation port each having one end sequentially disposed at a connection point between the first to fifth transmission lines and the other end extending radially; One end is disposed at the connection point between the first to sixth transmission lines, the other end is radially extended toward the center, and is composed of first to sixth low pass filter (LPF) blocks for blocking harmonics, Each of the first to sixth low pass filter (LPF) blocks First and second coupling lines having one end connected to one of the first to sixth transmission lines and disposed adjacent to the center; A third coupling line having one end connected to one of the first output port, the input port, the second output port, and the isolation port and disposed between the first and second coupling lines; Folded with LPF characteristics characterized in that it consists of an open stub connected to the other end of the first to third coupling line and bent to form an angle between the first to third coupling line 30 degrees to extend radially Ring-hybrid directional coupler in structure.

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