TWM452475U - Bias-displacement Cassegrain frequency-dividing antenna system of a very wideband multiple channel - Google Patents

Description

Extremely wide frequency multi-channel partial displacement Cassegrain crossover antenna system

This creation is about the antenna system, especially an offset Cassegrain dichroic antenna system with extremely wide frequency and multi-channel.

The patents and materials related to this creation are as follows: US 6,774,861 (Reference 1), US 6,512,485 B2 (Ref. 2), V.Agrawal, W. Imbriale "Design of a dichroic cassegrain subreflector" IEEE Trans.on Antenna & Propagation, 1979 Vol.27, Issue4, Page 466~473 (Ref. 3), US3231892 (Ref. 4).

The traditional cross-section mirror (Dichroic Sub-dish) is set to the antenna of either the offset set (Casset) or the Cassegrain reflector without the offset. The crossover (dichroic) The design is to use uniform and period dichroic elements for the arrangement of the metal elements on the mirror surface, that is, all the components on the mirror surface are of the same specification and are uniform with each other. Periodic arrangement.

Frequency selection surface (Frequency) Selective surface (FSS)) or generally in antenna applications, the cross-section (Dichroic, the mechanism that reflects and transmits the frequency of the incident wave separately) mirror is used in the sub-dish (Sub-dish, or secondary reflection) Sub-reflection to separate two different frequency bands. The signal of one of the frequency bands penetrates the frequency division mirror and is concentrated to a prime focus point. The signal from the other band is reflected and concentrated to an Image focus point. This traditional multi-band antenna design has been disclosed in references three and four. However, FSS or crossover technology is generally only used in mixed or large-capacity military or dedicated satellite communications, as well as some special applications, and almost no receiving antennas for low-cost commercial satellite communication ground.

In traditional FSS or dichroic techniques, the high frequency feed horn is placed at the image focus point and the low frequency feed horn is placed at the prime focus point. Both the high frequency band and the low frequency band are narrow bandwidths, and the bandwidth used for communication is usually 5% of the carrier frequency. In reference two, the high frequency band has two separate frequency bands, one is 20 GHz, the other is 30 GHz, and the low frequency band is at 12.4 GHz, which is about 5% of bandwidth in each frequency band.

In the traditional antenna design, the carrier frequency ratio of the high frequency band and the low frequency band is mostly 1.5 or more. In traditional antenna designs, multi-band uses a Dichroic Sub-dish design, as seen in reference three. High and low frequency bands The Bobby gap is very large, such as 12 GHz and 6 GHz (the ratio of the high frequency band to the low frequency band is generally around 2) and both use the normal Cassegrain reflection without offset. The recent application of satellite television (DBS) has only begun to use Offset Cassegrain Reflector, as disclosed in references one and two. The ratio of the high frequency band to the low frequency band is between 1.5 and 2, for example, 30 GHz/12 GHz and 20 GHz/12 GHz, but the offset dichroic Sub-dish is designed due to the offset (offset). The relationship between the incidence of radio waves incident on the dichroic sub-dish is not perpendicular to the incident and the angle varies greatly, which makes the design more difficult, and thus the conventional Dichroic design cannot reach the wide frequency ( Wide-bandwidth).

Current applications, especially in the next generation of satellite TV applications (DBS), traditional TV broadcasting can not meet the rapid development of modern multimedia such as HDTV, 3D HDTV, IPTV (Voice on demand, VOD), two-way communication Internet, etc. On the demand. The current concept of satellite communication requires that a satellite must be able to use two Ku bands and one Ka band simultaneously as the frequency band of the downlink signal, and also use one Ku band and one Ka band as the frequency band for uploading signals to meet the current large number. The need for communication. Therefore, the bandwidth used must be large enough, and according to the current design of the next generation satellite television system, the bandwidth requirement for the high frequency band is much higher than the bandwidth requirement of the low frequency band.

The traditional design of a dichroic Cassegrain antenna (as described in references 1 and 2) places the high frequency feed horn at the image focus point; that is, the divided sub-mirror reflects the waves. The principle of its ability to reflect electric waves is achieved by the use of a metal sheet structure on a dichroic to induce electromagnetic resonance at this high frequency band. In general, this design has a limited bandwidth unless complex multi-layer dichroic surfaces are used. However, the design of such a multilayer resonant metal piece cannot be made to function as a broadband because the incident angle of the electric wave changes too much. Therefore, the design of the traditional crossover antenna has failed to meet the requirements of the next generation satellite TV.

Therefore, the creators of this creation need to conceive a new technology to improve their problems.

Therefore, the purpose of this creation is to solve the above-mentioned problems in the prior art. In this creation, a very wide-band multi-channel partial displacement Cassegrain crossover antenna system is proposed, which aims to pass through a low frequency band and a high frequency band. The choice can make both frequency bands be extra-broadband, generally more than 10% or even 35% of the bandwidth, especially the high frequency band is wider than the low frequency band. So for the next generation of satellite television (DBS), the low frequency band must be met in the Down-link band of 10.7 GHz to 12.75 GHz, at high frequencies. The segment has a 17 GHz upload (up-link), a 18-20 GHz down-link and a 24 GHz upload-up (link-up), which is a 17-24 GHz bandwidth requirement of almost 35%. The design of this case has reached the above bandwidth requirements. The proportion of high frequency band and low frequency band in this case is very small. For example, 17GHz/12.75GHz has a ratio of only 1.3. In this case, an offset sub-dish is used to reduce the blockage caused by the sub-mirror. It will make a new concept and breakthrough in the design of traditional cross-country (dichroic) and Cassegrain reflector (Cassegrain Reflector). First, because the bandwidth requirement of the high frequency band is much higher than the low frequency band, the metal piece on the frequency division sub-mirror surface is designed to perform electromagnetic resonance on the incident wave of the low frequency band, and the electric wave of the low frequency band is reflected and concentrated to the image focus ( Image focus point). The high-frequency electric wave penetrates the frequency-divided sub-mirror and is concentrated to the prime focus point. In addition, in this case, the metal piece structure of the frequency division sub-mirror surface is not a conventional uniform distribution and periodic arrangement design, but a structural design in which the metal piece is finely adjusted according to the incident angle of the electric wave is adopted. Due to the design of the single layer dichroic surface, the sensitivity to the incident angle of the radio wave is not very large. The metal sheet structure on the sub-mirror surface can be divided into several regions, and each region has its own metal sheet. The arrangement of the structures, the metal sheet structures in each area are uniformly distributed and periodically arranged. The metal sheet structure in different areas has fine adjustments. The configuration of the metal sheet structure is mainly based on the angle of the incident wave. This configuration allows the frequency dividing sub-mirror in this case to receive incident waves from different angles, and both have excellent low-frequency reflectivity and high frequency. Transmittance and the ability to achieve extremely wide frequency.

In order to achieve the above purpose, the present invention proposes an extremely wide frequency multi-channel partial displacement Cassegrain crossover antenna system, wherein the antenna system is used for transmitting and receiving signals from satellites, and the antenna system can perform antennas on ground devices and satellites. The uploading and transmitting of the signal between the antenna system includes: a parabolic mirror; the parabolic mirror has a corresponding focus axis, and the parabolic mirror is disposed on one side of the axis in an offset manner The parabolic mirror has a focus point on a focus axis; a sub-dish piece, the frequency division sub-mirror is mainly a lens arranged along a hyperboloid, the frequency division The secondary lens has a prime focus point that coincides with the focus of the parabolic mirror and also includes an image focus point on the focus axis of the hyperboloid mirror, in the present invention The frequency dividing sub-lens is disposed on one side of the axis in an offset manner, and the axis of the mirror surface and the axis of the mirror surface of the parabolic mirror do not have to coincide; The sub-lens lens can reflect the low-frequency signal and pass the high-frequency signal; at least one primary feed horn is a conventional angle or other designed transceiver mechanism, and the signal receiving point of the front end overlaps with the main focus. Receiving a high-frequency electric wave that penetrates the frequency-dividing sub-mirror or transmitting the high-frequency electric wave toward the frequency-dividing sub-mirror; at least one image feed horn is a conventional angle or other designed transceiver mechanism, the front end of which is The signal receiving point overlaps the image focus for receiving low frequency waves reflected from the frequency dividing sub-mirror or low frequency The electric wave is emitted toward the frequency dividing sub-mirror; wherein the frequency dividing sub-mirror reflects the low frequency signal, and the low frequency signal is received by the image radio wave transmitting and receiving mechanism; and the high frequency signal penetrates the frequency dividing sub mirror, and the main frequency Received by the radio wave transceiver.

The features of the present invention and its advantages can be further understood from the description below, and please refer to the attached drawings when reading.

In view of the structural composition of the case, and the functions and advantages that can be produced, in conjunction with the drawings, a preferred embodiment of the present invention is described in detail below.

Please refer to FIG. 1 , which shows a configuration diagram of components in the present invention. The present invention comprises the following components: an antenna system 10 for transmitting and receiving signals from satellites for uploading and transmitting signals between the ground unit and the satellite antenna. The antenna system mainly comprises: a paraboloidal reflector 12; the parabolic mirror has a corresponding focal axis 20, and the focus axis has a pair of focal points 22 that should be parabolized, wherein the antenna A focal length 24, which is the distance between the focus and the apex of the parabolic mirror 12, has a radiation aperture 26 that is a cross-section that accepts external radiation. In the present invention, the parabolic mirror 12 is arranged in an offset manner. One side of the axis.

A dichroic sub-dish 14 is mainly a lens that is arranged in a hyperbolidal configuration, and may be a flat surface when implemented. The frequency dividing sub-mirror 14 has a radiation profile 28 and a prime focus point 30a. The main focus 30a coincides with the focus 22 of the parabolic mirror 12 and also includes an image focus point 30b. On the focus axis of the hyperboloid 14, the focus axis may or may not coincide with the focus axis 20 of the mirror surface, but at a distance from the main focus 30a. In the present invention, the frequency dividing sub-mirror 14 is disposed on one side of the axis in an offset position, and the axis of the mirror surface may or may not coincide with the axis of the mirror surface of the parabolic mirror 12.

The frequency dividing sub-mirror 14 can reflect the low frequency signal and pass the high frequency signal. The low frequency band in this case refers to the frequency from 9 GHz to 15 GHz, while the high frequency band refers to the frequency from 17 GHz to 30 GHz.

A primary feed horn 16 is a conventional angle or other designed transceiver mechanism, and a signal receiving point at the front end thereof overlaps with the main focus 30a for receiving high frequency waves penetrating the frequency dividing sub mirror 14. Or, the high frequency electric wave is emitted toward the frequency dividing sub-mirror 14.

An image feed horn 18 is a conventional angle or other designed transceiver mechanism, and a signal receiving point at a front end thereof overlaps the image focus 30b for receiving low frequency waves reflected from the frequency dividing sub-mirror 14 or The low frequency electric wave is emitted toward the frequency dividing sub-mirror 14.

The main radio wave transmitting and receiving mechanism 16 and the image radio wave transmitting and receiving mechanism 18 in the present case all have the appearance of a conventional horn or other design shape.

The material selection of the frequency-division hyperboloid mirror can be referred to the structure disclosed in paragraphs 4 and 5 of the description of the preferred embodiment of U.S. Patent No. 6,774,861 B2. The following is a general description: refer to FIG. 2A, FIG. 2B and FIG. 2C, wherein the frequency dividing sub-mirror 14 comprises upper and lower layers of Kevla or Mylar or other similar material surface 33, and is composed of a Kevla ^® honeycomb or other entity. The material structure is distinguished. Bipolar grid-like or other shaped structure dividing the sub-mirror 32 of the frequency selective surface 14 comprises copper etch on Kevla ^® or Mylar or other similar surface material 32. By applying this type, the signals of the high frequency band and the low frequency band can be respectively penetrated and reflected, so that the signals of the two frequency bands are separated, and the reflected low frequency signals are directed to the image wave transmitting and receiving mechanism 18. . And the passed high frequency signal is directed to the main wave transmitting and receiving mechanism 16.

Referring to FIG. 3A and FIG. 3B, a cross-sectional view showing the positional relationship between the frequency division sub-mirror 14 and the main radio wave transmitting/receiving mechanism 16 and the image radio wave transmitting and receiving mechanism 18 in the present creation is shown. An incident wave is incident on the frequency dividing sub-mirror 14 at an angle A1. The left side of the figure shows the arrangement of the metal piece components of the mirror of the frequency dividing sub-mirror 14 , and the right side shows the return loss measured under different frequencies. In the figure, six horizontally polarized electromagnetic waves are tested, wherein the six electromagnetic waves are incident at an angle perpendicular to the frequency dividing sub-mirror 14, which has different crossing angles with respect to the arrangement angle of the metal sheets, and these intersections The angles are 15°, 30°, 45°, 60°, 75° and 90°, please refer to the metal sheet structure on the left side of Figure 3. In Figure 3 The measured return loss is measured at different frequencies when the incident angle A1 is 90 degrees. It shows that the feedback loss is quite low at frequencies from 9 GHz to 15 GHz, so most of the incident waves in this band can be reflected from the frequency dividing sub-mirror 14 without significant loss. The relative feedback loss is relatively high when the frequency is in the range of 17 GHz to 30 GHz, so most of the incident waves in this frequency band will penetrate the frequency dividing sub-mirror 14 without reflection. Therefore, from the above relationship, we can understand that the system of the present invention has good reflectivity with respect to the frequency dividing sub-mirror 14 at a frequency of 9 GHz to 15 GHz (low frequency), so the signal can be reflected to the main wave transmitting and receiving mechanism 16, and Received by the main radio wave transceiver unit 16. In addition, the system of the present invention has good penetration with respect to the frequency dividing sub-mirror 14 at a frequency of 17 GHz to 30 GHz (high frequency), so the signal can penetrate the frequency dividing sub-mirror 14 and serve as the image transmitting and receiving mechanism. 18 received. In the figure, six horizontally polarized electromagnetic waves are tested, which have different crossing angles with respect to the arrangement angle of the metal sheets, and the crossing angles are 15°, 30°, 45°, 60°, 75°, and 90, respectively. °. From the feedback loss on the right side of the figure, it can be seen that the effect does not change much at different angles.

The low frequency is 5 GHz to 7 GHz and the high frequency is 9 GHz to 12 GHz with respect to the above-described conventional techniques, and 9 GHz to 15 GHz (low frequency) and 17 GHz to 30 GHz (high frequency) are used in the present case. It can be seen that the bandwidth in this case is far wider than the bandwidth used by the prior art. In this case, a relatively high frequency portion is used, so the bandwidth can be increased to 35% of the carrier, which is much better than 5% of the prior art. The technique of this method can widen the bandwidth of communication, so The amount of traffic has also increased. Moreover, it can be seen from the above that the so-called low frequency in the present case is actually a high frequency with respect to the conventional technique, and the so-called high frequency in the present case does not actually use this frequency band in the prior art. Therefore, there has been a great breakthrough in technology in this case.

Please refer to FIG. 4A and FIG. 4B, wherein the incident electromagnetic wave is incident on the frequency dividing sub-mirror 14 in the direction of horizontal polarization, wherein the incident angles are 15°, 30°, 45°, 60°, 75°, and 90, respectively. ° (Refer to the structural configuration diagram on the left side of the figure). It shows that the value of the feedback loss becomes smaller with respect to different incident angles, especially when it is high frequency. Therefore, we need to consider this feature in designing the frequency dividing sub-mirror 14. The configuration and arrangement of the sheet metal components must be appropriately designed such that at different angles, the curve of the feedback loss can tend to a feedback loss curve with an ideal incident angle of 90°.

Please refer to FIG. 5A and FIG. 5B, wherein the incident electromagnetic wave is incident on the frequency dividing sub-mirror 14 in the direction of vertical polarization, wherein the incident angles are 15°, 30°, 45°, 60°, 75°, and 90, respectively. °. It shows that the feedback loss value becomes smaller with respect to different incident angles, which is a characteristic that would be disadvantageous for reflection at low frequencies. Therefore, we need to consider this feature in designing the frequency dividing sub-mirror 14. The configuration and arrangement of the sheet metal components must be appropriately designed such that at different angles, the curve of the feedback loss can tend to a feedback loss curve with an ideal incident angle of 90°.

Please refer to FIG. 6, which shows the angle between the radio waves transmitted by the radio wave transceiver mechanism and the frequency dividing sub-mirror 14, which is shown in the figure between the two ends of the frequency dividing sub-mirror 16 (θ1 and θ2). Great change Chemical. Similarly, in the figure, the angle between the transmitting waves of the image wave transmitting and receiving mechanism 18 and the ends of the frequency dividing sub-mirror 14 (θ3 and θ4) also undergoes a large change, so the frequency dividing sub-mirror material and The physical response between the transmitted waves is also very different. Therefore, according to the experimental results of FIG. 3, FIG. 4 and FIG. 5, as shown in FIG. 2D and FIG. 2E, the present invention claims to change the metal piece on the frequency dividing sub-mirror 14 according to different angles of the incident wave. structure. Preferably, the metal sheet structure on the frequency dividing sub-mirror 14 can be divided into a plurality of regions, each of which has an arrangement of respective metal sheet structures, and the metal sheet structures in each region are uniformly distributed and periodically arranged. The different metal sheet structures in different regions have been finely adjusted. The configuration of the metal sheet structure is mainly based on the angle of the incident wave. According to Figure 4 and Figure 5, the response of the metal sheet structure to the incident angle does not change within plus or minus thirty degrees, so the distinction of the area is not necessarily too fine; every 20 to 30 degrees can be separated as a region. .

As shown in FIG. 7, when there are multiple satellite signal transmission paths L1, L2, and L3, respectively, the signal receiving system in the present case has the parabolic mirror 12 and the frequency dividing sub-mirror 14 arranged in the same manner as the above-mentioned FIG. In the above, only a plurality of radio wave transceivers are used in this example to receive signals from different satellites.

The advantage of this case is that after the selection of the above low frequency band and high frequency band, the two frequency bands can be made of extra-broadband, generally more than 10% or even 35% of the bandwidth, especially in the high frequency band. The lower frequency band is more broadband. So for the next A generation of satellite television (DBS), which requires a low frequency band to be satisfied in the 10.7 GHz to 12.75 GHz Down-link frequency band, and a high frequency band with 17 GHz up-link and 18-20 GHz downlink (Down-link) and 24 GHz up-link, a total of 17 to 24 GHz is almost 35% of the bandwidth requirement. The design of this case has reached the above bandwidth requirements. In this case, the ratio of the high frequency band to the low frequency band is very small. For example, 17GHz/12.75GHz has a ratio of only 1.3. In this case, an offset sub-dish is used to reduce the radio wave blockage caused by the frequency division sub-mirror. It will make a new concept and breakthrough in the design of traditional crossover and Cassegrain mirrors. In addition, in this case, the metal piece structure of the frequency dividing sub-mirror is divided into a plurality of regions, and each region has an arrangement of respective metal sheet structures, and the metal sheet structures in each region are uniformly distributed and periodically arranged. Different regions have different metal sheet structures. The configuration of the metal sheet structure is mainly based on the angle of the incident wave. This configuration allows the frequency dividing sub-mirror in the present case to receive incident electric waves from different angles, and both have excellent low-frequency reflectance and high-frequency transmittance and reach an extremely wide bandwidth.

In summary, the humanized design of this case is quite in line with actual needs. The specific improvement of the existing defects is obviously a breakthrough improvement advantage compared with the prior art, and it has an improvement in efficacy and is not easy to achieve. The case has not been disclosed or disclosed in domestic and foreign literature and market, and has complied with the provisions of the Patent Law.

The detailed description above is for one of the possible embodiments of the present creation. The description of the present invention is not intended to limit the scope of the patents, and the equivalents of the inventions are not included in the scope of the present invention.

10‧‧‧Antenna system

12‧‧‧Parabolic mirror

14‧‧‧Dividing sub-mirror

16‧‧‧Main radio wave transceiver

18‧‧‧Image radio wave transceiver

20‧‧‧focus axis

22‧‧‧ Focus

24‧‧‧ Focus length

26,28‧‧‧radiation profile

30a‧‧‧ main focus

30b‧‧‧Image focus

32‧‧‧ frequency selection surface

33‧‧‧Front mirror surface material

Figure 1 is a schematic view of the first embodiment of the present invention.

FIG. 2A, FIG. 2B and FIG. 2C are schematic diagrams showing the structure of a frequency division sub-mirror of the prior art.

Figure 2D is a front view of the surface metal sheet structure of the frequency dividing sub-mirror of the present invention.

Figure 2E is a perspective view of the surface metal sheet structure of the frequency dividing sub-mirror of the present invention.

FIG. 3A and FIG. 3B show the feedback loss data of the six horizontally polarized electromagnetic waves for the frequency division sub-mirror, wherein the six electromagnetic waves are incident at an angle perpendicular to the frequency dividing sub-mirror.

4A and 4B show that the frequency division is incident on the frequency division sub-mirror in the direction of horizontal polarization, and the loss data is fed back with respect to different incident angles.

Figure 5A and Figure 5B show that the incident electromagnetic wave is incident on the frequency dividing sub-mirror in the direction of vertical polarization, and the loss data is fed back with respect to different incident angles.

Figure 6 shows the radio wave pre-splitting sub-mirror emitted by the radio wave transceiver A schematic diagram of the angle between them.

Figure 7 is a schematic view of the second embodiment of the present invention.

10‧‧‧Antenna system

12‧‧‧Parabolic mirror

14‧‧‧Dichroic sub-dish

16‧‧‧Main radio wave transceiver

18‧‧‧Image radio wave transceiver

20‧‧‧focus axis

22‧‧‧ Focus

24‧‧‧ Focus length

26,28‧‧‧radiation profile

30a‧‧‧Prime focus point

30b‧‧‧Image focus point

Claims (7)

An extremely wide-band multi-channel partial displacement Cassegrain crossover antenna system, wherein the antenna system is used for transmitting and receiving signals from satellites, and the antenna system can perform signal uploading between the ground device and the antenna on the satellite and Downstream, the antenna system includes: a parabolic mirror; the parabolic mirror has a corresponding focus axis, the parabolic mirror is disposed on one side of the axis in an offset manner; a frequency divider mirror (dichroic sub-dish), the frequency dividing sub-mirror is mainly a lens with a pair of curved surfaces, the frequency dividing sub-mirror has a prime focus point, which coincides with the focus of the parabolic mirror And an image focus point, the focus axis of the hyperboloid may coincide or not coincide with the focus axis of the parabolic mirror on the focal axis of the hyperboloid, and the frequency dividing mirror is offset The (offset) manner is disposed on one side of the axis, and the axis of the mirror surface and the axis of the mirror surface of the parabolic mirror may coincide or not coincide; wherein the frequency dividing sub mirror reflects the low frequency signal And passing the high frequency signal; at least one primary feed horn is a conventional angle or other external transceiver mechanism, and the signal receiving point of the front end overlaps with the main focus for receiving the penetration Frequency sub-mirror The wave or the high frequency electric wave is emitted toward the frequency dividing sub-mirror; at least one image feed horn is a conventional angle or other designed transceiver mechanism, and the signal receiving point of the front end overlaps the image focus for Receiving a low frequency electric wave reflected from the frequency dividing sub-mirror or transmitting the low frequency electric wave toward the frequency dividing sub-mirror; wherein the frequency dividing sub-mirror reflects a low frequency signal, and the low frequency signal is received by the image radio wave transmitting and receiving mechanism; and the high frequency The signal is transmitted through the frequency dividing sub-mirror and received by the main radio wave transceiver; and wherein the frequency dividing sub-mirror comprises a metal piece structure, and the metal piece on the frequency dividing sub-mirror is changed according to different angles of the incident wave. structure. For example, the extreme wide-band multi-channel partial-displacement Cassegrain crossover antenna system described in claim 1 wherein the low frequency band refers to a frequency from 9 GHz to 15 GHz, and the high frequency band refers to a frequency from 17 GHz to 30 GHz. For example, the extreme wide-band multi-channel partial-displacement Cassegrain crossover antenna system described in claim 1 wherein the main radio wave transceiver mechanism and the image radio wave transceiver mechanism have a conventional horn shape or other designed appearance. For example, the ultra-wideband multi-channel partial-displacement Cassegrain crossover antenna system described in claim 1 is characterized in that the metal piece structure is divided into a plurality of regions, and each region has an arrangement of respective metal sheet structures. In this way, the metal sheet structure in each area is uniformly distributed and periodically arranged, and the metal sheet structure in different areas is not Similarly, the configuration of the metal sheet structure is mainly adjusted according to the angle of the incident wave. The extreme wide-band multi-channel partial-displacement Cassegrain crossover antenna system as described in claim 1 includes a plurality of primary feed horns for a conventional angle or other design. a mechanism, wherein at least one of the main radio wave transceivers has a signal receiving point at a front end thereof that is close to the main focus, and each of the main wave transmitting and receiving units respectively receives radio waves from the corresponding satellites, and the radio waves penetrate the high frequency electric wave of the frequency dividing sub mirror or The high frequency electric wave is emitted toward the frequency dividing sub mirror. An extremely wide-band multi-channel partial-displacement Cassegrain crossover antenna system as described in claim 1, comprising a plurality of image feed horns, wherein at least one of the image wave transceivers The signal receiving point of the front end is close to the image focus for receiving low frequency electric waves reflected from the frequency dividing sub-mirror or transmitting low frequency electric waves toward the frequency dividing sub mirror. For example, the extreme wide-band multi-channel partial displacement Cassegrain crossover antenna system described in claim 1 or 4, wherein the metal sheet structure is distributed every 20 to 30 degrees. The separation configuration is because the response of the sheet metal structure to the incident angle does not change too much within plus or minus thirty degrees.