S / x dual-frequency dielectric rod full-loaded feed

Abstract

The application discloses a kind of S / X dual-frequency dielectric rod complete loading feed, belong to the field of ring focus double reflection surface antenna.The application includes feed body, waveguide cavity is provided in feed body from left to right, and shaped dielectric rod is arranged on the central axis in waveguide cavity;The shaped dielectric rod from left to right is conical section, cylindrical section and curve shaped section;The waveguide cavity from left to right is tapered cavity section, round cavity section, shaped cavity section and opening radiation cavity section;Four waveguide slits are arranged on the circumference of shaped cavity section, and the waveguide slits are distributed at 90°;Curve shaped section and shaped cavity section are obtained using least square method fitting.The application solves the deficiency of common nozzle feed, multiple horn feed and coaxial feed, and can meet the reception and transmission of signals working in S frequency band and X frequency band with good standing wave and radiation direction performance.

Description

Technical Field

[0001] This invention belongs to the field of ring-focal dual-reflector antennas, and specifically refers to an S / X dual-frequency dielectric rod fully loaded feed source. Background Technology

[0002] In satellite communications, to maximize communication capacity, satellites now offer multi-band communication services. Multi-band shared antennas allow a single antenna feed system to operate simultaneously on two or more satellite communication bands, achieving multi-purpose use of a single station and significantly reducing the construction cost of earth stations. Multi-band shared aperture antennas are currently a research hotspot, with the key being the development of the feed system that determines the electrical characteristics of the aperture antenna. The feed system is the core of the reflector antenna, and its performance largely determines the overall function and performance of the reflector antenna. Commonly used multi-band feed network systems mainly include the following three types:

[0003] 1. Common nozzle horn feed network system:

[0004] The common nozzle horn feed network system consists of a multi-frequency feed and a back-end network. The multi-frequency feed usually adopts the structure of a corrugated horn or a light wall horn. This technology is relatively mature and can solve the problem of multi-frequency multiplexing of the feed well. However, the signals of all frequency bands propagate in the common port of the horn, the mode in the horn is relatively complex, the antenna efficiency is limited, and the design of the back-end network of the feed is more difficult.

[0005] 2. Multi-speaker feeder network system:

[0006] The system consists of multiple horn arrays, mainly a five-horn feed network. Compared with the common nozzle horn feed network system, this system eliminates the back-end multi-frequency division multiplexing structure. However, when the high and low frequency intervals are small, the spacing between the outer horn arrays is large, resulting in low feed illumination reflector efficiency and affecting the overall performance of the antenna.

[0007] 3. Coaxial feed network system:

[0008] The system consists of a coaxial feed and a back-end power supply network, and can be divided into metal-nested coaxial feeds and dielectric rod-loaded coaxial feeds. Signals of different frequency bands propagate in relatively independent channels with good isolation between frequency bands. When the high and low frequency intervals are large, it can well balance the performance of high and low frequency bands, and the overall performance of the feed is excellent. However, when the high and low frequency intervals are small, the coaxial feed also has the problems of strong inter-frequency coupling and poor impedance matching characteristics of the low-frequency channel. Summary of the Invention

[0009] In view of this, this invention proposes an S / X dual-band dielectric rod fully loaded feed for use in a ring-focal dual-reflector antenna. Compared to a coaxial feed, where the high-frequency channel has a metal wall, resulting in a TEM mode as the fundamental mode of the low-frequency channel, this invention, with its fully loaded dielectric rod and the absence of a metal wall around the rod, achieves a TE11 mode as the fundamental mode of the low-frequency channel. Furthermore, this invention results in better standing wave ratio (SWR) in the low-frequency channel, and the absence of the influence of the high-frequency channel from the coaxial feed during low-frequency radiation, leading to higher antenna aperture efficiency. Compared to a common-nozzle feed, this invention solves the design challenges of the back-end demultiplexing network, implementing demultiplexing design from the feed itself and reducing the degrading effect of higher-order modes of the demultiplexer on the feed pattern. Compared to a multi-horn feed, it eliminates the issue of low-frequency horn array spacing, effectively improving the performance of the low-frequency antenna. This invention can meet the requirements of good SWR and radiation direction performance for both receiving and transmitting signals operating in the S-band and X-band. This invention also features a compact structure, small size, light weight, convenient operation, low processing cost, easy processing, and no debugging required, making it widely applicable.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A fully loaded S / X dual-frequency dielectric rod feed includes a feed body 1, within which a waveguide cavity extends from left to right. Four waveguide slots 5, distributed at 90° intervals, are located on the circumference of the waveguide cavity. A shaped dielectric rod 2 is positioned along the central axis of the waveguide cavity. The shaped dielectric rod 2, from left to right, consists of a conical segment 201, a cylindrical segment 202, and a curved shaped segment 203. The waveguide cavity, from left to right, consists of a tapered cavity segment 8, a circular cavity segment 9, a shaped cavity segment 4, and an open radiating cavity segment 6. The waveguide slots 5 are located on the circumference of the shaped cavity segment 4.

[0012] The specific shape of the curve shaping segment 203 is fitted using the third-order least squares method.

[0013] The specific shape of the shaping cavity 4 was fitted using the fourth-order least squares method.

[0014] Furthermore, the length of the conical segment 201 is 3λ1-5λ1, and the radius gradually increases from left to right, with a maximum radius of r1. The value of r1 is:

[0015] r1=1.3*300 / (2.06*f1*sqrt(ε))

[0016] Where f1 is the X-band frequency, λ1 is the wavelength corresponding to f1, and ε is the dielectric constant of the shaped dielectric rod 2;

[0017] The radius of the cylindrical segment 202 is the same as the maximum radius r1 of the conical segment 201, and the length of the cylindrical segment 202 is 6λ1-8λ1;

[0018] The length of the curve shaping segment 203 is λ1-2λ1, and the radius of the leftmost end of the curve shaping segment 203 is the same as the radius of the cylindrical segment 202.

[0019] Furthermore, the length of the tapered cavity segment 8 is 0.9λ²-1.5λ², and the radius gradually decreases from left to right, with a maximum radius of r². The value of r² is:

[0020] r² = 1.18 * 300 / (3.412 * f²)

[0021] Where f2 is the S-band frequency and λ2 is the wavelength corresponding to f2; the minimum radius of the tapered cavity segment 8 is the same as the radius of the cylindrical segment 202;

[0022] The radius of the circular cavity segment 9 is the same as the radius of the cylindrical segment 202, and the length is 3λ1-5λ1;

[0023] The length of the shaped cavity segment 4 is 1.5λ2-2.5λ2, and the radius of the leftmost end of the shaped cavity segment 4 is the same as the radius of the cylindrical segment 202.

[0024] Furthermore, the projection of the waveguide slot 5 is rectangular, with the long side of the rectangle parallel to the shaping dielectric rod 2; an I-shaped filter 3 is provided around the waveguide slot 5, the I-shaped filter 3 includes multiple rectangular waveguide cavities 301 whose central axes coincide and which decrease in size sequentially from the outer surface of the feed body 1 to the interior of the feed body 1, and I-shaped cavities 302 inserted between every two adjacent rectangular waveguide cavities 301, the I-shaped cavities 302 decreasing in size sequentially from the outer surface of the feed body 1 to the interior of the feed body 1, and whose central axes coincide with the central axes of the rectangular waveguide cavities 301, wherein the lower surface of the innermost rectangular waveguide cavity 301 is the shaping cavity segment 4.

[0025] Furthermore, the length of the open radiation section 6 is λ2-2λ2. The open radiation section 6 includes multiple cylindrical waveguide cavities whose central axes coincide and whose radii increase sequentially from the rightmost end of the shaped cavity section 4 to the rightmost end of the feed body 1.

[0026] Furthermore, the right surface of the feed body 1 is provided with multiple annular choke grooves 7 centered on the open radiation cavity section 6.

[0027] Furthermore, the radius of the circular cavity segment 9 is the same as that of the cylindrical segment 202, and the circular cavity segment 9 provides support for the shaping medium rod 2.

[0028] Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0029] 1. This invention uses a shaped dielectric rod to transmit X-band signals. By designing the shape of the shaped section of the dielectric rod curve, the standing wave and radiation pattern of the feed X-band can be adjusted, thereby controlling the performance of the antenna.

[0030] 2. This invention uses a shaped dielectric rod to transmit X-band signals. The signal transitions to a circular waveguide port through the conical section of the dielectric rod and the tapered cavity section of the waveguide cavity, which can be connected to back-end network devices and has good adaptability.

[0031] 3. This invention uses a shaped dielectric rod to transmit X-band signals. Due to the constraint effect of the dielectric rod on the high-frequency signal, the X-band and S-band have a strong isolation effect, avoiding mutual interference between the two frequency bands.

[0032] 4. This invention uses a feed cavity and an I-shaped filter to extract the S-band signal and adjust the standing wave ratio of the S-band signal.

[0033] 5. The present invention employs a choke slot to adjust the S-band radiation pattern of the feed source.

[0034] 6. This invention is small in size and light in weight, requires no debugging, can save a lot of labor costs, and can quickly realize the assembly of S / X band feed systems, making it suitable for mass production. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of a fully loaded S / X dual-frequency dielectric rod feed source in an embodiment of the present invention.

[0036] Figure 2 yes Figure 1 Cross-sectional view.

[0037] Figure 3 This is a simulation diagram of the shaping cavity segment in an embodiment of the present invention.

[0038] Figure 4 This is a simulation diagram of the curve shaping segment in an embodiment of the present invention.

[0039] Figure 5 This is the test radiation pattern of the feed S-band antenna in an embodiment of the present invention.

[0040] Figure 6 This is the test radiation pattern of the feed X-band antenna in an embodiment of the present invention.

[0041] Among them, the feed body-1, the shaped dielectric rod-2, the I-shaped filter-3, the shaped cavity section-4, the waveguide slot-5, the open radiation cavity section-6, the annular choke groove-7, the tapered cavity section-8, the circular cavity section-9, the conical section-201, the cylindrical section-202, the curved shaped section-203, the rectangular waveguide cavity-301, and the I-shaped cavity-302. Detailed Implementation

[0042] The following describes specific embodiments and appendices. Figure 1-4 The present invention will be further described as follows:

[0043] like Figure 1 , Figure 2 The S / X dual-frequency dielectric rod fully loaded feed shown includes a feed body 1; the feed body 1 has a waveguide cavity that runs from left to right, and four waveguide slots (5) distributed at 90° on the circumference of the waveguide cavity; a shaped dielectric rod 2 is provided on the central axis of the waveguide cavity; the shaped dielectric rod 2 consists of a conical section 201, a cylindrical section 202 and a curved shaped section 203 from left to right; the waveguide cavity consists of a tapered cavity section 8, a circular cavity section 9, a shaped cavity section 4 and an open radiating cavity section 6 from left to right; the waveguide slots 5 are located on the circumference of the shaped cavity section 4;

[0044] Among them, such as Figure 4 As shown, the specific shape of the curve shaping segment 203 is fitted by five discrete control points using the third-order least squares method, and the horizontal and vertical coordinate positions of the five control points are optimized by an optimization algorithm.

[0045] like Figure 3 As shown, the specific shape of the shaping cavity 4 is fitted by 7 discrete control points using the 4th order least squares method, and the horizontal and vertical coordinate positions of the 7 control points are optimized by an optimization algorithm.

[0046] The optimization algorithms for both the curve shaping segment 203 and the shaping cavity segment 4 are optimized to achieve a shaping shape with a standing wave ratio better than 1.5:1, an illumination level between -8dB and -15dB at the illumination angle of the feed pattern, and an equalization within the illumination angle better than 3dB.

[0047] Furthermore, the length of the conical segment 201 is 3λ1-5λ1, and the radius gradually increases from left to right, with a maximum radius of r1. The value of r1 is:

[0048] r1=1.3*300 / (2.06*f1*sqrt(ε))

[0049] Where f1 is the X-band frequency, λ1 is the wavelength corresponding to f1, and ε is the dielectric constant of the shaped dielectric rod 2;

[0050] The radius of the cylindrical segment 202 is the same as the maximum radius r1 of the conical segment 201, and the length of the cylindrical segment 202 is 6λ1-8λ1;

[0051] The length of the curve shaping segment 203 is λ1-2λ1, and the radius of the leftmost end of the curve shaping segment 203 is the same as the radius of the cylindrical segment 202;

[0052] Specifically, the direction from the conical section to the shaped curve section is the direction of X-band signal transmission, and the direction from the shaped curve section to the conical section is the direction of X-band signal reception. In this embodiment, the above data is calculated using f1 = 7.7 GHz, λ1 = 38.96 mm, and ε = 2.5. The diameter of the conical section of the shaped dielectric rod gradually decreases towards the X-band signal reception direction, matching the air waveguide and giving the feed system a low reflection coefficient. The shaped curve section is fitted using the least squares method, with its diameter gradually decreasing towards the X-band signal transmission direction, giving the feed a large illumination angle. The illumination level at a half-illumination angle of approximately 50° is between -12 dB and 16 dB, maximizing the antenna's X-band efficiency and achieving maximum antenna gain.

[0053] The length of the tapered cavity segment 8 is 0.9λ²-1.5λ², and the radius gradually decreases from left to right, with a maximum radius of r². The value of r² is:

[0054] r² = 1.18 * 300 / (3.412 * f²)

[0055] Where f2 is the S-band frequency and λ2 is the wavelength corresponding to f2; the minimum radius of the tapered cavity segment 8 is the same as the radius of the cylindrical segment 202;

[0056] The radius of the circular cavity segment 9 is the same as that of the cylindrical segment 202, and the length is 3λ1-5λ1; the circular cavity segment 9 and the cylindrical segment 202 cooperate to support the shaping medium rod 2.

[0057] The length of the shaped cavity segment 4 is 1.5λ2-2.5λ2, and the radius of the leftmost end of the shaped cavity segment 4 is the same as the radius of the cylindrical segment 202;

[0058] Furthermore, the length of the open radiation section 6 is λ2-2λ2, and the open radiation section 6 includes multiple cylindrical waveguide cavities whose central axes coincide and whose radii increase sequentially from the rightmost end of the shaped cavity section 4 to the rightmost end of the feed body 1.

[0059] Specifically, the diameter of the tapered cavity section gradually increases towards the X-band signal receiving direction, transitioning to the size of an X-band air circular waveguide. The rear end can be connected to X-band air waveguide devices, such as a TE21 mode tracker with pinhole coupling, which has good adaptability. The diameter of the shaped cavity section gradually increases towards the S-band signal transmitting direction, giving the S-band signal pattern a larger illumination angle.

[0060] In this embodiment, the above data is calculated using f2 = 2GHz and λ2 = 150mm, and the shaping medium rod is glued and fixed to the circular cavity segment.

[0061] Furthermore, the projection of the waveguide slot 5 is rectangular, with the long side of the rectangle parallel to the shaping dielectric rod 2; an I-shaped filter 3 is provided around the waveguide slot 5, the I-shaped filter 3 includes multiple rectangular waveguide cavities 301 whose central axes coincide and which decrease in size sequentially from the outer surface of the feed body 1 to the interior of the feed body 1, and I-shaped cavities 302 inserted between every two adjacent rectangular waveguide cavities 301, the I-shaped cavities 302 decreasing in size sequentially from the outer surface of the feed body 1 to the interior of the feed body 1, and whose central axes coincide with the central axes of the rectangular waveguide cavities 301, wherein the lower surface of the innermost rectangular waveguide cavity 301 is the shaping cavity segment 4.

[0062] Specifically, the waveguide slots interact with the I-shaped filter to couple out S-band signals, giving the feed system a low reflection coefficient.

[0063] Furthermore, the right surface of the feed body 1 is provided with multiple annular choke grooves 7 centered on the open radiation cavity section 6.

[0064] The S-band signal reception process (which is reciprocal to the signal reception and transmission process) is as follows: The S-band signal illuminates the open radiation cavity section of the waveguide cavity, exciting two degenerate TE11 modes. After passing through the shaped cavity section, one mode is coupled out by a pair of waveguide slots corresponding to 180 degrees and a pair of I-shaped filters, while the other mode is coupled out by another pair of waveguide slots corresponding to 180 degrees and an I-shaped filter.

[0065] The X-band signal reception process (which is reciprocal to the signal reception and transmission process) is as follows: The X-band signal illuminates the shaping dielectric rod, and the curved shaping segment of the dielectric rod excites two degenerate TE11 modes, which are coupled into the dielectric rod and propagate backward through the cylindrical segment. The energy is coupled to the air waveguide by the combined action of the conical segment and the tapered cavity segment of the waveguide cavity.

[0066] Specifically, such as Figure 5 , Figure 6 The image shows a test pattern of a 7.3-meter loop-focal antenna with a fully loaded S / X dual-band dielectric rod feed. The first sidelobe of the antenna pattern in both the S and X bands is better than -15 dB.

[0067] In summary, this invention can realize the reception and transmission of S / X band signals. Compared with the common nozzle feed system, it has the advantage of a large frequency span. Compared with the multi-horn feed system, it has the advantage of high antenna efficiency. Compared with the metal nested coaxial feed and the dielectric rod partially loaded coaxial feed, it has the advantages of good standing wave matching and high antenna efficiency. Moreover, this invention has the advantages of compact structure and easy processing, and can meet the needs of the ring focal antenna system.

[0068] It should be noted that the above descriptions and examples are intended to help those skilled in the art understand the present invention, but are not intended to limit the scope of protection of the present invention. Any modifications, scaling, alterations, improvements, and / or simplifications that do not depart from the essential content of the present invention should fall within the scope of protection of the present invention.

Claims

1. A fully loaded S / X dual-frequency dielectric rod feed, comprising a feed body (1), wherein the feed body (1) has a waveguide cavity extending from left to right, and four waveguide slots (5) distributed at 90° on the circumference of the waveguide cavity; characterized in that, A shaping dielectric rod (2) is provided on the central axis of the waveguide cavity; the shaping dielectric rod (2) consists of a conical section (201), a cylindrical section (202), and a curved shaping section (203) from left to right; the waveguide cavity consists of a tapered cavity section (8), a circular cavity section (9), a shaped cavity section (4), and an open radiating cavity section (6) from left to right; the waveguide slot (5) is provided on the circumference of the shaped cavity section (4); The projection of the waveguide slot (5) is rectangular, with the long side of the rectangle parallel to the shaping dielectric rod (2). An I-shaped filter (3) is provided around the waveguide slot (5). The I-shaped filter (3) includes multiple rectangular waveguide cavities (301) whose central axes coincide and which gradually decrease in size from the outer surface of the feed body (1) to the interior of the feed body (1), and I-shaped cavities (302) inserted between every two adjacent rectangular waveguide cavities (301). The I-shaped cavities (302) gradually decrease in size from the outer surface of the feed body (1) to the interior of the feed body (1), and their central axes coincide with the central axes of the rectangular waveguide cavities (301). The lower surface of the innermost rectangular waveguide cavity (301) is the shaping cavity segment (4). The specific shape of the curve shaping segment (203) is fitted by the third-order least squares method. The specific shape of the shaping cavity segment (4) was fitted using the fourth-order least squares method.

2. The fully loaded S / X dual-frequency dielectric rod feed source according to claim 1, characterized in that, The length of the conical segment (201) is 3λ1-5λ1, and the radius gradually increases from left to right, with a maximum radius of r1. The value of r1 is: r1=1.3*300 / (2.06*f1*sqrt(ε)) Where f1 is the X-band frequency, λ1 is the wavelength corresponding to f1, and ε is the dielectric constant of the shaped dielectric rod (2); The radius of the cylindrical segment (202) is the same as the maximum radius r1 of the conical segment (201), and the length of the cylindrical segment (202) is 6λ1-8λ1; The length of the curve shaping segment (203) is λ1-2λ1, and the radius of the leftmost end of the curve shaping segment (203) is the same as the radius of the cylindrical segment (202).

3. The fully loaded S / X dual-frequency dielectric rod feed source according to claim 2, characterized in that, The length of the tapered cavity segment (8) is 0.9λ²-1.5λ², and the radius gradually decreases from left to right, with a maximum radius of r². The value of r² is: r2=1.18*300 / （3.412 *f2） Where f2 is the S-band frequency and λ2 is the wavelength corresponding to f2; the minimum radius of the tapered cavity segment (8) is the same as the radius of the cylindrical segment (202); The radius of the circular cavity segment (9) is the same as the radius of the cylindrical segment (202), and the length is 3λ1-5λ1; The length of the shaped cavity segment (4) is 1.5λ2-2.5λ2, and the radius of the leftmost end of the shaped cavity segment (4) is the same as the radius of the cylindrical segment (202); The length of the open radiating cavity segment (6) is λ2-2λ2. The open radiating cavity segment (6) includes multiple cylindrical waveguide cavities whose central axes coincide and whose radii increase sequentially from the rightmost end of the shaped cavity segment (4) to the rightmost end of the feed body (1).

4. The fully loaded S / X dual-frequency dielectric rod feed source according to claim 1, characterized in that, The right surface of the feed body (1) is provided with multiple annular choke grooves (7) centered on the open radiation cavity section (6).

5. The fully loaded S / X dual-frequency dielectric rod feed source according to claim 3, characterized in that, The radius of the circular cavity section (9) is the same as that of the cylindrical section (202), and the circular cavity section (9) provides support for the shaping medium rod (2).

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