Planar waveguide magic tee

Abstract

The present invention relates to a planar waveguide magic tee. The magic tee may comprise: first and second ports which function as output ports during power decoupling, function as input ports during power coupling, and extend in opposite directions; a third port which functions as an input port during power decoupling, functions as an output port during power coupling, and extends from the intersection point of the first and second ports in a first direction perpendicular to the extension lines of the first and second ports; a fourth port having a function of a termination load as a termination port and extending from the intersection point in a second direction opposite to the first direction; and a matching post disposed at the intersection point to perform an impedance matching function, wherein the first to fourth ports may be formed in a waveguide structure and arranged on a plane.

Description

Planar waveguide magic tee

[0001] The present invention relates to a planar waveguide magic tee used in radio and wireless communication systems, wherein the E-arm is arranged in the same plane as the H-arm, thereby satisfying a wideband transmission requirement while maintaining a low shape of the E-arm.

[0002] A conventional waveguide magic tee is composed of first, second, third, and fourth ports (1, 2, 3, 4) as illustrated in Fig. 1. Among these, the third port (Sum port) (3), which is an input port, is configured as an H-female, and the fourth port (Σ port) (4) is configured as an E-female. When used as a power separator or power combiner, the fourth port (4) is used as a termination port. In order to transmit the power input to the third port (3) to the first port (1) and the second port (2), a matching post is required for isolation.

[0003] The fourth port (4) requires an E-arm with a length of at least twice the wavelength to induce waveguide termination, which poses a limitation in implementing a low-height magic tee. Specifically, when a conventional waveguide magic tee functions as a power separator or power combiner as shown in Fig. 1, the fourth port (4) must be a termination port. In this case, the length of the E-arm is required to be approximately twice the minimum wavelength depending on the frequency band used. In this case, the vertical length of the E-arm complicates the structure of the magic tee, which poses a limitation in implementing a low-profile shape of the system.

[0004] Therefore, a planar waveguide magic tee is required that satisfies the broadband transmission requirements by arranging the E-arm on the same plane as the H-arm, thereby maintaining the low profile of the E-arm. To reduce the height of a magic tee, a common method is to bend the fourth port, which is the vertical portion of the magic tee, into a horizontal structure, but this method has limitations in satisfying the broadband transmission requirements.

[0005] Meanwhile, U.S. Patent No. 5,132,646A (hereinafter referred to as "Patent Document 1") discloses a coaxial planar magic tee. Patent Document 1 implements the magic tee using a coaxial transmission line as a port. The coaxial transmission line is a coaxial cable made of conductors rather than a waveguide, and in this case, the power handling limitations inherent in the coaxial structure limit high transmission power.

[0006] Meanwhile, a matching post performing an impedance matching function may be provided at the intersection of the magic tee. In this regard, Korean Patent Publication No. KR100967153B1 (hereinafter referred to as “Patent Document 2”) discloses a waveguide having a magic T structure. However, in Patent Document 2, the matching post is simply a cone-shaped peak with a sharp end. However, this configuration has the following problems in terms of frequency bandwidth and high power handling. In terms of frequency bandwidth, the frequency bandwidth is limited to about 20%, making it difficult to cover the maximum bandwidth (Full bandwidth (40%): 40% of the total possible frequency band of the propagation bandwidth). In terms of high power handling, problems such as an arcing phenomenon may occur.

[0007] [Prior Art Literature]

[0008] [Patent Document]

[0009] (Patent Document 1) U.S. Patent Publication No. US5132646A (registered on July 21, 1992)

[0010] (Patent Document 2) Korean Patent Publication KR100967153B1 (registered on July 5, 2010)

[0011] An object of the present invention is to provide a planar waveguide magic tee that satisfies broadband transmission requirements by arranging the E-arm in the same planar plane as the H-arm, thereby maintaining a low profile of the E-arm.

[0012] The present invention, which aims to solve the above-described problem, relates to a planar waveguide magic tee. The magic tee comprises: first and second ports, which perform the function of an output port when power is separated and the function of an input port when power is combined, and which extend in opposite directions; a third port, which performs the function of an input port when power is separated and the function of an output port when power is combined, and which extends in a first direction perpendicular to the extension line of the first and second ports from the intersection of the first and second ports; a fourth port, which functions as a termination load as a termination port, and which extends in a second direction opposite to the first direction from the intersection; and a matching post, which is arranged at the intersection and performs an impedance matching function, wherein the first to fourth ports are formed in a waveguide structure and can be arranged in a plane.

[0013] According to an embodiment of the present invention, the fourth port includes a lower waveguide portion extending in the same layer as the third port, and an upper waveguide portion extending in an upper layer of the lower waveguide portion, and at the intersection side, a plurality of step portions having different heights may be formed in the upper waveguide portion to improve transmission bandwidth and optimize for a specific frequency band.

[0014] According to an embodiment of the present invention, the plurality of step portions may include first to fourth step portions arranged in an extension direction of the fourth port from the intersection, the first step portion may have a first height, the second step portion may have a second height higher than the first height, and the third and fourth step portions may have third and fourth heights that are sequentially smaller than the second height.

[0015] According to an embodiment of the present invention, the first step portion and the second step portion are in communication with each other, the second, third, and fourth step portions are separated from each other by side walls, and each of the first to fourth step portions may have an upper portion closed and a lower portion open to the lower waveguide portion.

[0016] According to an embodiment of the present invention, the matching post is mounted on the lower surface of the intersection, and the upper portion can enter the inner space of the first step portion.

[0017] According to an embodiment of the present invention, the matching post is formed by stacking a plurality of conductive layers having a circular cross-section whose outer diameter decreases toward the top in a cone shape, and the uppermost conductive layer may protrude upwards so that the lower surface starts from a circular cross-section and the upper surface becomes an elliptical cross-section.

[0018] According to the present invention, by introducing a matching transformer structure at the intersection of the magic tee to optimize the function of the magic tee and obtain maximum transmission performance in a desired frequency band, the E-arm can be designed to be planar with the H-arm, thereby implementing a low profile and simple structure.

[0019] In addition, it has a low-loss transmission power separation / combination function by showing excellent isolation of more than 20dB through a matching post structure designed integrally into the lower housing.

[0020] In addition, the same phase and power can be transmitted to the first and second ports, and the matching transformer at the intersection of the first and second ports has a structure with four stages, so that the transmission bandwidth is wide (40%) and the bandwidth can be adjusted so that maximum performance is achieved at a specific bandwidth.

[0021] Figure 1 is a perspective view illustrating a conventional vertical waveguide magic tee.

[0022] FIG. 2 is a perspective view illustrating a planar waveguide magic tee according to the present invention.

[0023] Fig. 3 is a perspective view showing the state in which the waveguide termination ports of Fig. 2 are coupled.

[0024] FIG. 4 is a graph showing the frequency bandwidth and transmission performance of a planar waveguide magic tee according to the present invention.

[0025] FIG. 5 is a diagram showing an E-field simulation of a planar waveguide magic tee according to the present invention.

[0026] FIG. 6 is a perspective view illustrating a matching post applied to a planar waveguide magic tee according to the present invention.

[0027] Figure 7 is a perspective view showing an example of a 4-way combiner module of a planar waveguide magic tee.

[0028] Figures 8 (a) and (b) are side views comparing the sizes of the system with and without the planar waveguide magic tee applied.

[0029] Hereinafter, specific details for implementing the present invention will be described with reference to the attached drawings. In describing the present invention, detailed descriptions of related known functions that are obvious to those skilled in the art and that may unnecessarily obscure the gist of the present invention will be omitted.

[0030] Fig. 2 is a perspective view illustrating a planar waveguide magic tee according to the present invention. Fig. 3 is a perspective view illustrating a state in which the waveguide end ports of Fig. 2 are coupled.

[0031] Referring to FIGS. 2 and 3, the waveguide magic tee according to the present invention includes first to fourth ports (100, 200, 300, 400) that are cross-connected to each other, and a matching post (500). The waveguide magic tee performs both the functions of a power separator and a power combiner. The first to fourth ports (100, 200, 300, 400) are all formed as waveguide structures and arranged in a plane. That is, the E-arm is designed to be coplanar with the H-arm.

[0032] When performing the power separator function, the power input as one input port to the third port (300) of the microwave device is separated and transmitted to the first and second ports (100, 200) as two output ports. Conversely, when performing the power combiner function, the power input as two input ports to the first and second ports (100, 200) is combined and transmitted to the third port (300) as one output port.

[0033] The first and second ports (100, 200) function as output ports when power is separated, and function as input ports when power is combined. The first and second ports (100, 200) extend in opposite directions in the horizontal direction of the magic tee.

[0034] The third port (300) functions as an input port when power is separated, and as an output port when power is combined. The third port (30) extends in a first direction (d1) perpendicular to the extension line of the first and second ports (100, 200) from the intersection (p) of the first and second ports (100, 200).

[0035] The fourth port (400) is a termination port and has the function of a termination load, and extends from the intersection point (p) in a second direction (d2) opposite to the first direction.

[0036] The fourth port (400) includes a lower waveguide portion (410) extending on the same level as the third port (300), and an upper waveguide portion (420) extending on an upper level of the lower waveguide portion (410). On the intersection (p) side, the upper waveguide portion (420) is formed with a plurality of step portions having different heights to improve transmission bandwidth and optimize for a specific frequency band, which may be composed of first to fourth step portions (421, 422, 423, 424).

[0037] These multiple step-change sections are referred to as matching transformers (M). The matching transformers (M) are devices that optimize the operation of the magic tee and achieve optimal performance in a desired frequency band. The matching transformers (M) perform the role of converting signals or adjusting impedances, thereby ensuring efficient signal processing within the system and achieving maximum transmission performance.

[0038] The first to fourth step portions (421, 422, 423, 424) are arranged in the extension direction of the fourth port (400) from the intersection point (p). The first step portion (421) has a first height (h1), and the second step portion (422) has a second height (h2) that is higher than the first height (h1). The third and fourth step portions (423, 424) have third and fourth heights (h3, h4) that are sequentially smaller than the second height (h2).

[0039] The first step portion (421) and the second step portion (422) are connected to each other, and the second, third, and fourth step portions (422, 423, 424) are separated from each other by side walls (425, 426). Each of the first to fourth step portions (421, 422, 423, 424) has an upper portion closed and a lower portion open to the lower waveguide portion (410).

[0040] The first and second step sections (421, 422) are designed to implement the planar shape of a planar waveguide magic tee. The first and second step sections (421, 422) are used to define the signal path and form the structure of the magic tee. The length of the first and second step sections is designed to be a quarter of the wavelength to provide optimal performance at a specific frequency.

[0041] The third and fourth steps (423, 424) are introduced to apply a load for waveguide termination. The lengths of the third and fourth steps (423, 424) are designed to match the specifications of the loads applied. This ensures proper operation of the termination load and adequate handling of the power generated in the transmission system.

[0042] Fig. 4 is a graph showing the frequency bandwidth and transmission performance of a planar waveguide magic tee according to the present invention. Fig. 5 is a diagram showing an E-field simulation of a planar waveguide magic tee according to the present invention.

[0043] Referring to Fig. 4, the horizontal axis of the graph represents frequency, and the vertical axis represents the ratio of the size of the input and output. Each line of S11, S22, S33, S44, S23, and S41 represents an s-parameter (scattering parameter), and the numbers represent the numbers of the output port and the input port in order. S11 represents the input-output ratio (reflection loss, reflection coefficient) confirmed at the first port of the present invention. S22 represents the input-output ratio (reflection loss, reflection coefficient) confirmed at the second port of the present invention. S33 represents the input-output ratio (reflection loss, reflection coefficient) confirmed at the third port of the present invention. S44 represents the input-output ratio (reflection loss, reflection coefficient) confirmed at the fourth port of the present invention. S23 represents the ratio (insertion loss, gain) confirmed at the second port of the present invention to the third port. S41 represents the ratio (insertion loss, gain) of the input of the first port confirmed at the fourth port of the present invention.

[0044] The figures in this graph represent the performance of the planar waveguide magic tee according to the present invention, as measured by a computer simulation (HFSS) for electromagnetic wave analysis. The device exhibited excellent isolation of over 20 dB across the entire range (0.8 Fc to 1.2 Fc, 40%), confirming its low-loss transmission power separation / combination capability.

[0045] Referring to Fig. 5, the E-field simulation results of Fig. 5 represent the TE mode analyzed in HFSS for the planar waveguide magic tee according to the present invention. This is because the value input from the third port is isolated by the matching post (500), resulting in the same phase being output from the first and second ports.

[0046] Therefore, the planar waveguide magic tee according to the present invention can implement a low profile and simple structure by designing the E-arm to be planar with the H-arm by introducing a matching transformer (M) structure to optimize the function of the magic tee at the intersection of the magic tee and obtain maximum transmission performance in a desired frequency band.

[0047] In addition, it has a low-loss transmission power separation / combination function by showing excellent isolation of more than 20dB through a matching post structure designed integrally into the lower housing.

[0048] In addition, the same phase and power can be transmitted to the first and second ports, and the matching transformer (M) at the intersection of the first and second ports has a structure with four stages, so that the transmission bandwidth is wide (40%) and the bandwidth can be adjusted so that the maximum performance is achieved at a specific bandwidth.

[0049] FIG. 6 is a perspective view illustrating a matching post applied to a planar waveguide magic tee according to the present invention.

[0050] Referring to FIG. 6 together with FIG. 2, a matching post (500) performing an impedance matching function is provided at the intersection (p) of the planar waveguide magic tee according to the present invention. The matching post (500) is mounted on the lower surface of the intersection (p), and the upper portion enters the internal space of the first step portion (421).

[0051] The matching post (500) is formed by stacking a plurality of conductive layers (510) in a cone shape, each having a circular cross-section whose outer diameter decreases toward the top. Among these, the uppermost conductive layer (511) starts from a circular cross-section on the lower surface and protrudes upward so that the upper surface becomes an elliptical cross-section. By combining this special matching post (500) shape with the above-described matching transformer (M) structure, the full waveguide bandwidth (40%) can be satisfied: the bandwidth of the radio waveguide can satisfy 40% of the total possible frequency band, and the arcing phenomenon can be prevented when handling high power.

[0052] Fig. 7 is a perspective view illustrating an example of a 4-way combiner module of a planar waveguide magic tee. Figs. 8 (a) and (b) are side views comparing the sizes of systems with and without a planar waveguide magic tee applied.

[0053] The planar waveguide magic tee using the matching post (500) proposed in the present invention was applied to a 4-way module, which is a core component of a W-band (80 GHz) high-power amplifier, as shown in Fig. 7. A total of 6 matching posts (500) and matching transformers (M) were applied, and 3 were used each in the input and output sections to minimize interference between modules. In this way, it can be applied to various applications due to the shape minimization and weight reduction of the microwave structure, and low loss during power separation and coupling. Referring to Fig. 8, the planar waveguide magic tee (Fig. 8 (a)) according to the present invention has the advantage of space utilization because there is no vertical protrusion part (L) of the conventional vertical waveguide magic tee (Fig. 8 (b)).

[0054] The scope of protection in this field is not limited to the description and expression of the embodiments explicitly described above. Furthermore, it should be noted that obvious modifications or substitutions within the technical field to which the present invention pertains may not limit the scope of protection of the present invention.

[0055] [Explanation of symbols]

[0056] 100: Port 1

[0057] 200: Second port

[0058] 300: Third port

[0059] 400: Port 4

[0060] 410: Lower waveguide section

[0061] 420: Upper waveguide section

[0062] 421~424: 1st to 4th steps

[0063] 425, 426: Side walls

[0064] 500: Matching Post

[0065] p: intersection

[0066] d1: Extension direction of the third port

[0067] d2: Extension direction of the 4th port

[0068] h1~h4: Height of the first to fourth steps

Claims

1. First and second ports that perform the function of an output port when power is separated and the function of an input port when power is combined, and extend in opposite directions; A third port that performs the function of an input port when power is separated and performs the function of an output port when power is combined, and extends in a first direction perpendicular to the extension lines of the first and second ports from the intersection of the first and second ports; A fourth port having the function of a termination load as a termination port and extending in a second direction opposite to the first direction from the intersection; and It is placed at the above intersection and includes a matching post that performs an impedance matching function. A planar waveguide magic tee, characterized in that the first to fourth ports are formed as a waveguide structure and arranged on a plane.

2. In paragraph 1, The fourth port includes a lower waveguide portion extending in the same layer as the third port, and an upper waveguide portion extending in an upper layer of the lower waveguide portion. A planar waveguide magic tee, characterized in that, on the above intersection side, a plurality of step portions having different heights are formed in the upper waveguide portion to improve the transmission bandwidth and optimize it for a specific frequency band.

3. In paragraph 2, The above plurality of step portions include first to fourth step portions arranged in the extension direction of the fourth port from the intersection, A planar waveguide magic tee, characterized in that the first step portion has a first height, the second step portion has a second height higher than the first height, and the third and fourth step portions have third and fourth heights that are sequentially smaller than the second height.

4. In paragraph 3, A planar waveguide magic tee, characterized in that the first step portion and the second step portion are in communication with each other, the second, third, and fourth step portions are separated from each other by side walls, and the first to fourth step portions each have an upper portion closed and a lower portion open to the lower waveguide portion.

5. In paragraph 4, A planar waveguide magic tee, characterized in that the above matching post is mounted on the lower surface of the intersection and the upper portion enters the inner space of the first step.

6. In paragraph 1, The above matching post is a planar waveguide magic tee characterized in that a plurality of conductive layers having a circular cross-section whose outer diameter decreases as it goes upward are laminated in a cone shape, and the uppermost conductive layer starts from a circular cross-section on the lower surface and protrudes upward so that the upper surface has an elliptical cross-section.

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