JPH08102618A - Multibeam antenna - Google Patents

Abstract

PURPOSE: To easily solve problems such as a power loss in large power transmission, to easily set up excitation distribution for low side lobe and to highly efficiently utilize a power supply for an amplifier. CONSTITUTION: This multibeam antenna is constituted of a reflector and primary radiator and each primary radiator constitute clusters 89 to 92 arranged in each beam, and is provided with plural antenna elements 401, 411 to 416 consisting of plural kinds having different radiation characteristics and plural amplifiers 201, 211 to 216 directly connected to respective antenna elements 401, 411 to 416.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-beam antenna, and more particularly to a multi-beam feeding system used as a primary radiator of a reflector antenna mounted on a satellite.

[0002]

2. Description of the Related Art With the increase in demand for satellite communication, it is required to increase the gain of an antenna mounted on the satellite to increase the communication capacity. Therefore, it is necessary to reduce the coverage area of the beam radiated from the antenna and efficiently radiate radio waves in a narrow area. Therefore, there is a need for a multi-beam satellite broadcasting system that covers a service area with a plurality of beams.

As an example, consider multibeam satellite communication using four beams as shown in FIG. Here, in order to effectively use the frequency, the same frequency is used every other beam. In order to effectively use this frequency, it is important to reduce the side lobe of the radiation pattern for the satellite antenna. For example, the radio wave radiated to the beam 1 needs to have low sidelobe characteristics in this region so that there is no interference with the coverage of the beam 3 using the same frequency.

As an antenna system which realizes such a low sidelobe characteristic, an antenna composed of a reflecting mirror 24 and a primary radiator 23 as shown in FIG. 2 can be considered. Here, the primary radiator consists of four clusters, as shown in FIG.
It is composed of 31,32,33,34. Each cluster is
Each forms one beam, and each is composed of seven antenna elements. Here, the cluster 31 forming the beam 1 is composed of antenna elements 1, 2, 3, 4, 5, 6, 7.
The cluster 32 forming the beam 2 includes antenna elements 6, 7,
A cluster 33, which is composed of 8, 9, 10, 11, and 12 and forms the beam 3, is composed of antenna elements 11, 12, 13, 14, 15, 16, and 17, and a cluster 34, which forms the beam 4, is an antenna element. It consists of 16, 17, 18, 19, 20, 21, 22. In this way, one beam is formed by multiple antenna elements,
By setting an appropriate excitation distribution for each antenna element, it is possible to make the composite pattern thereof have low sidelobe characteristics. In addition, here, due to the requirement to increase the beam crossover level (gain at the beam-beam boundary), some antenna elements that form a cluster are shared between adjacent beams (for example, antenna elements are used). 6 and 7 are used by both the beam 1 formed by the cluster 31 and the beam 2 formed by the cluster 32).

The above concept has already been applied to many satellite-mounted multi-beam antennas. The conventional method considered as the configuration of the power feeding system is shown below. Figure 7
Is an example showing a conventional configuration of a multi-beam feeding system,
The antenna elements 1 to 22 are combined (in the case of reception) or distributed (in the case of transmission) by the power feeding circuits 47, 48, 49 and 50 of the clusters corresponding to the respective beams. In each feeding circuit,
The configuration uses a distributor (combiner), a phase shifter, etc. so as to give a predetermined excitation distribution to the antenna elements forming each cluster. Amplifiers 101, 102, 103 and 104 are connected to the power feeding circuits 47, 48, 49 and 50, respectively, and amplify signals for transmission and reception. As this amplifier, a high output amplifier (specifically, a traveling wave type amplification tube or a solid-state amplifier) is used for transmission, and a low noise amplifier is used for reception. In addition, in this power feeding system configuration, the demultiplexers 205, 206, 207, 208, 209, 210 are respectively connected to the antenna elements 6, 7, 11, 12, 16, 17 that are shared between the adjacent beams to separate the two frequency bands. It In this method, the excitation distribution of the antenna element can be freely set in the feeding circuit, and therefore, there is an advantage that an optimum low sidelobe pattern for frequency reuse can be realized for each beam. However, this method is based on the premise that the frequency band of each beam does not change and cannot be changed flexibly according to the call volume of each beam.

The power supply system configuration of FIG. 8 can cope with a case where the frequency band and the amount of communication are flexibly changed between the beams. Here, the antenna elements 1 to 22 are combined or distributed by the feeding circuits 47, 48, 49, 50 of the clusters corresponding to the respective beams, as in the configuration of FIG. However, the antenna element 6, which is shared between the adjacent beams,
In 7, 11, 12, 16, and 17, since the frequency band of each beam is not fixed, the frequency band separation by the demultiplexer is not possible, so it is simply a distributor (combiner) 41, 42, 43, 44. , 46 are connected. The feeding circuits 47 and 48 are connected to the matrix amplifier 59, and the feeding circuits 49 and 50 are connected to the matrix amplifier 60. The matrix amplifier 59 is a 3 dB hybrid 51 and two amplifiers 55 and 56 connected to the output of the 3 dB hybrid 51.
And a hybrid connected to the output of this amplifier 55,56
It is composed of 52 and. Similarly, matrix amplifier
60 is a 3 dB hybrid 53, two amplifiers 57 and 58 connected to the output of this 3 dB hybrid 53, and this amplifier 5
It consists of a hybrid 54 connected to the outputs of 7,58. The matrix amplifier 59, 60 having such a configuration
In the above, the input signal is equally distributed by the hybrids 52, 54, amplified by the two amplifiers 55, 56 or 57, 58, and output to one port by the hybrids 51, 53 on the output side. As shown in the figure, even when two beams are input at the same time, the input and output are always at the same level with respect to the amplifier, and the output of each beam appears at different ports. In this case, even if there is an imbalance in the frequency band between the beams (difference in communication amount), the input to the amplifier is made uniform, so that the amplifier can always operate with high efficiency. Now, the ratio of the frequency band occupied by beam 1 and beam 3 to the entire frequency band is x (0 ≦ x ≦
1) and the maximum output power of one amplifier is Pmax, the power supply efficiency η of the amplifier is as follows. Here, the power supply efficiency indicates what ratio the output power actually output is to the maximum output power of the amplifier that can be output by the power supply (the same meaning applies in the following description). .

Η = 2 [2 × Pmax + 2 (1-x) Pmax] / (4Pmax) = 1.0 (1) Therefore, in this example, the power supply efficiency theoretically becomes 100%. As described above, the power feeding system configuration of FIG. 8 is very effective for a satellite communication system in which the communication amount varies between beams. However, there are the following problems.

Particularly when used as a transmitting antenna,
The power supply circuits 47, 48, 49, and 50 transmit a large amount of power, and it is difficult to form the excitation distribution with high accuracy in forming the hardware. Passive intermodulation (PIM, harmonics are generated, which affects receivers, etc.) and multipaction (because of high power, RF short circuit due to generation of secondary electrons)
It is necessary to consider in order to suppress the problem that a failure occurs in high power transmission. Also, if the frequency band is made flexible, loss will occur in the combiner (distributor) 41, 42, 43, 44, 45, 46 connected to the beam sharing element (half of the input to this antenna). Is a loss), the efficiency of the antenna is reduced, and heat is generated. A method of sharing elements by using a hybrid instead of a combiner has also been considered, but in this case, the excitation distribution of shared elements between beams is constrained, which is an optimum cluster suitable for low sidelobe. The excitation distribution cannot be set. Furthermore, since the isolation between the ports of the matrix amplifier, which is ideally infinite, can be realized only to a finite value, there is a problem that a signal of one beam leaks into a cluster of another beam. In this case, the isolation characteristics between the beams are deteriorated. The isolation level between the beams largely depends on the isolation characteristics between the ports of the matrix amplifier, and thus it may not be applicable to a satellite communication system that requires very high isolation between beams.

As a conventional method of constructing a power feeding system, a configuration as shown in FIG. 9 can be considered. In this configuration, the antenna element 1
22 to 22 are directly connected to the amplifiers 61 to 82, respectively. After that, power supply circuits 89, 90, 91, 92 are configured in cluster units,
Here, the excitation distribution that is optimal for lowering the side lobes is set. Antenna elements shared between beams 6, 7, 11, 12,
In 1617, combiners 83, 84, 85, 86, 87, 88 are respectively connected. In this combiner, only half of the electric power is transmitted in the direction of the antenna element, which causes a loss here, but since the signal transmitted to this portion has a small electric power, there is no particular problem. In the configuration of FIG. 9, particularly when used as a transmitting antenna, the antenna element and the amplifier are directly connected to each other, so that a portion for transmitting a large amount of power is short, and power loss, PIM, and multipaction which are problems in the configuration of FIG. Measures become easy. However, it is disadvantageous in terms of power supply efficiency of the amplifier. Similar to the above discussion, the maximum output power of all amplifiers is Pmax, the excitation power of the antenna elements forming the cluster is 1, and the peripheral antenna elements are α (0 <α ≦ 1), When the ratio of the frequency bands of the beams 1 and 3 is x, the power supply efficiency η is as follows. If η = [2 (1 + 6α) xPmax + 2 (1 + 6α) (1-x) Pmax] / 22Pmax = 2 (1 + 6α) / 22 (2) α = 0.1 (=-10dB), then η = 14.5%, and the power supply efficiency It turns out that is very bad.

[0010]

As described above, when the matrix feed system is used in the conventional feed system configuration in the multi-beam antenna, passive intermodulation and multipacion caused by transmitting a large amount of power are carried out. However, there is a problem that it is difficult to solve the problem of power loss, and it is difficult to sufficiently reduce the side lobe because the excitation distribution of the cluster is limited in order to reduce the power loss. Further, in the case of the power feeding system configuration in which the amplifier is directly connected to the antenna element, there is a problem that the power supply efficiency of the amplifier becomes extremely low.

The multi-beam antenna of the present invention has been made in view of such a problem, and its purpose is to easily solve the problems such as power loss related to high power transmission, and to have a low side lobe. It is an object of the present invention to provide a multi-beam antenna having a feeding system that can easily set the excitation distribution for optimization and can use the power source of the amplifier with high efficiency even when the communication amount between the beams varies.

[0012]

In order to achieve the above object, a multi-beam antenna of the present invention is a multi-beam antenna composed of a reflecting mirror and a primary radiator, wherein the primary radiator is A cluster provided for each beam is configured to include a plurality of antenna elements of a plurality of types having different radiation characteristics, and a plurality of amplifiers directly connected to each of the plurality of antenna elements.

Further, the multi-beam antenna of the present invention is
The ratio of the maximum output powers of the plurality of amplifiers matches the ratio of the excitation powers given to the corresponding plurality of antenna elements. Further, in the multi-beam antenna of the present invention, the ratio of excitation powers given to the plurality of antenna elements is represented by a specific integer ratio.

[0014]

That is, the multi-beam antenna of the present invention is
A multi-beam antenna composed of a reflector and a primary radiator, wherein the primary radiator comprises a plurality of antenna elements forming a cluster provided for each beam, and a plurality of antenna elements directly connected to the antenna element. An amplifier is used, and the plurality of antenna elements are composed of a plurality of types of antennas having different radiation characteristics.

Further, the multi-beam antenna of the present invention is
It is configured such that the ratio of the maximum output power of each of the plurality of amplifiers matches the ratio of the excitation power given to the corresponding plurality of antenna elements. Further, the multi-beam antenna of the present invention is configured such that the ratio of excitation powers given to the plurality of antenna elements is represented by a specific integer ratio.

[0016]

EXAMPLE In this example, a cluster composed of a plurality of antenna elements is used as a primary radiator of a reflecting mirror type antenna that transmits and receives radio waves via a reflecting mirror. Here, the excitation distribution (excitation amplitude, excitation phase) set for multiple antenna elements and the radiation directivity of the antenna elements are set appropriately in order to form the low sidelobe pattern required for frequency reuse between the beams. By adjusting to, the radiation directivity with a low side lobe is synthesized for each beam. Further, an amplifier is directly connected to each of the antenna elements forming the cluster and amplifies a signal input corresponding to each antenna element.

Further, here, by making the ratio of the maximum output power between the amplifiers coincide with the ratio of the excitation power of each antenna element, the output power corresponding to the excitation distribution is generated in each antenna element.

Further, by setting the ratio of the excitation powers applied to the antenna elements to be a simple integer ratio, the ratio of the maximum output power of the amplifier connected to the antenna elements is also a simple integer ratio. Set and generate output power according to that value.

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows the structure of the primary radiator of the multi-beam antenna according to the first embodiment. Here, as shown in FIG. 2, the antenna as a whole is composed of a reflecting mirror 24 and a primary radiator 23. In this example, as shown in FIG.
Assuming multi-beam satellite communication that covers a service area with four beams, the same frequency is reused every other beam (beam 1 and beam 3 have the same frequency f).
a, beam 2 and beam 4 have the same frequency fb). Here, beams 1, 2, 3, and 4 are formed by clusters 501, 502, 503, and 504, respectively, and the cluster 501 includes antenna elements 401, 411, 41.
2,413,414,415,416, cluster 502 is antenna element 402,
415, 416, 417, 418, 419, 420, the cluster 503 is composed of antenna elements 403, 419, 420, 421, 422, 423, 424, and the cluster 504 is composed of antenna elements 404, 423, 424, 425, 426, 427, 428. Here, an example in which a horn antenna is used as the antenna element is shown, but the antenna element may be one other than this method. Horn antennas 401, 402 at the center of each cluster,
The aperture diameters of 403 and 404 are larger than those of others, so that the beam width of the radiation directivity is narrowed and the gain is increased. Further, in order to increase the antenna gain at the crossover portion which is the boundary of beam coverage, the antenna element is shared between adjacent beams (clusters). For example, antenna elements 415 and 416 are shared by beams 1 and 2. Here, by giving an appropriate excitation distribution (excitation amplitude and excitation phase) to the seven antenna elements forming the cluster, it is possible to easily realize the side lobe reduction of each beam pattern. In particular, by reducing the sidelobe level in the other beam coverage that shares the frequency, the inter-beam isolation can be increased and the frequency can be reused. Further, in this embodiment, by setting the antenna aperture diameter of the antenna element at the center of the cluster to be large, the radiation directivity is set so as to be higher than that of the other antenna elements. With such a configuration, it is possible to realize an optimum cluster configuration for simultaneously achieving high gain at the edge portion and low side lobe in the desired area in beam coverage.

FIG. 4 shows the structure of the feeding system of the primary radiator.
In this embodiment, the antenna elements 401 to 404 and 411 to 428 are directly connected to the amplifiers 201 to 204 and 211 to 228, respectively. Each amplifier is connected to the power feeding circuits 89, 90, 91, 92 for each cluster. In this power feeding circuit, an excitation distribution that realizes low sidelobe radiation directivity is set for each antenna element. For example, the power supply circuit is composed of several distributors (combiner in the case of reception), phase shifters, etc. By setting the distribution ratio and phase amount of these components, each antenna element can be excited to a predetermined frequency. Amplitude and excitation phase can be given. The antenna elements 415, 416, 419, 420, 423, 424 that are shared between the beams (between clusters) have a combiner (a distributor in the case of reception) 83, 84, 85, 86, 8 between the amplifier and the feed circuit.
7,88 are connected to each other and combine (distribute) the signals from each power supply circuit. The combiner (distributor) can be formed as a simple T-branch. This power supply system can be used for both transmission and reception. In the case of transmission, a high power amplifier (HPA) is used as an amplifier, and in actuality, a traveling wave type amplifier (TW
T) or solid-state amplifier (SSPA) is used. In the case of reception, a low noise amplifier (LNA) is used as an amplifier.

Below, let us consider the case where the transmission antenna is considered as the power supply efficiency of the amplifier, assuming that the amplifiers are all the same. It is assumed that the maximum output powers of the amplifiers 201 to 204 and 211 to 228 are all Pmax. Regarding the excitation distribution, in each cluster, when the level of the excitation power given to the central antenna element (401, 402, 403, 404 in the example of FIG. 1) is set to 1, the surrounding antenna elements (cluster 50 of FIG.
In 1 the antenna elements 411,412,413,414,415,416) have α
The excitation power of (α is not 0) is given. The proportion of beams 1 and 3 occupied in the entire frequency band is x (0 ≦ x ≦
In the case of 1), the power supply efficiency η of the amplifier is as shown in equation (2). In the embodiment of the present invention, since the gain of the antenna elements in the periphery is low, it is necessary to set the excitation power as large as that for the antenna element having a small aperture in the periphery.
Therefore, in the conventional method, the value is about α = 0.1 (= -10 dB), but in the present embodiment, it is several times that ratio, for example, α = 0.
It should be around 5 (= -3dB). When α = 0.5,
η = 36.4%, which is several times more efficient than the conventional method.

As described above, in this embodiment, the following effects can be obtained by forming a cluster with antenna elements having different radiation directivities and directly connecting an amplifier to each of the antenna elements. (1) By changing and setting the radiation directivity of the antenna elements forming the cluster, it is possible to realize an optimum configuration for high gain and low sidelobe.
This is important for improving antenna efficiency and for effective frequency utilization in satellite communications and satellite broadcasting systems using multi-beams. (2) Since the antenna element and the amplifier are directly connected, the transmission line of high power is the minimum part in the case of transmission, so the loss due to high power, passive intermodulation (PIM), multi-action It is relatively easy to deal with such problems. For example, in order to reduce the PIM, a manufacturing method such as integral molding of the power feeding circuit is taken, but in the case of the first embodiment, manufacturing / manufacturing considering such a situation can be easily performed. Further, in the case of reception, the line loss from the antenna element to the amplifier can be minimized, and the deterioration of G / T (gain-to-noise temperature ratio) due to the line loss can be prevented. (3) With the configuration of the power supply system of the present embodiment, high power supply efficiency can be obtained even when there is a change in communication amount between beams and the frequency band is changed accordingly. From this, it is very effective as an application such as a satellite-mounted antenna used in a satellite mobile communication system, which is expected to have a large fluctuation in communication amount. (4) The power supply circuit is a region where the signal is at a low power level,
There is no problem such as heat generation due to line loss, and a power supply circuit can be manufactured easily by using a planar circuit such as a microstrip line, which is small and thin.

Next, in the configuration of the feeding system shown in FIG. 4, the maximum output power of the amplifier connected to each antenna element corresponds to the amplifier element 401, 402, 403, 404 at the center of the cluster.
A configuration is also conceivable in which Pmax is set for 201, 202, 203, 204 and αPmax is set for the amplifiers 211-228 corresponding to the peripheral antenna elements 411-428 of the cluster. In this case, the power supply efficiency η of the amplifier is expressed as follows. η = sum of output power of all beams / sum of maximum output power of amplifier = [2 (1 + 6α) × Pmax + 2 (1 + 6α) (1-x) Pmax] / [(4 + 18α) Pmax] = (1 + 6α) / (2 + 9α) (3) Therefore, assuming α = 0.5, η = 61.5%.

With the above-mentioned configuration, the power supply efficiency can be further increased, and it can be said that it is more and more effective for the mobile satellite communication system in which the amount of communication between beams is largely varied. In addition, this power feeding system configuration clearly shows a method of optimizing the amplifier by using the index of maximum output power with the power supply efficiency of the amplifier as an evaluation function. From this, it is shown that there are two types of amplifiers, one for the central antenna element and the other for the peripheral antenna elements. Therefore, if you make many amplifiers with the same characteristics
This will simplify the manufacturing and adjustment processes.

The excitation distribution is set by the power supply circuit, and the excitation phase is also adjusted in some cases. In such a situation, the maximum output power of the amplifier connected to the antenna element at the center of the cluster is Pmax, and the maximum output power of the amplifier connected to the antenna elements around it is αPmax.
And The amplification factors of the amplifiers are all the same. The operating point (back-off level) of the amplifier is set so that the input-to-output linearity is guaranteed even if all the bands are concentrated on a certain beam, and the output power at that time is set to the maximum output power. Is defined as In addition, it can be seen from Equation (3) that the larger α is, the higher the power efficiency is. Therefore, it is possible to further increase the efficiency by making α as large as possible (in some cases, 1 or more).

Further, in the present embodiment, the same effects can be obtained even if the following modifications are made. (1) Any method such as an antenna element, a power feeding line, a power feeding circuit component, etc. may be used. The effect is the same no matter what method is used. (2) Any means can be used to make the radiation directivity of the antenna element different. Although the size of the aperture of the antenna is changed in the embodiment, other shapes may be changed, or the antenna system itself may be changed. (3) The cluster system has been described by taking the configuration of seven antenna elements as an example as shown in FIG. 1. However, the same effect can be obtained by using another system such as the case of using nine antenna elements. is there. Also, regarding the sharing of the antenna elements in the adjacent clusters, the case where two antenna elements are shared is shown in FIG. 1, but it is also possible to share a different number of antenna elements such as sharing one element. If there is an antenna element used independently for one beam among the antenna elements forming the cluster (there may be a plurality of antenna elements), the number of antenna elements shared by adjacent clusters is arbitrary. (4) The configuration of the power supply circuit is not limited to the example shown in FIG. For example, a method of providing a frequency converter and converting to a low frequency band to configure a power supply circuit can be considered.
In this case, there are advantages that the power supply circuit component can be easily manufactured, and the power supply loss can be reduced. Similarly, for the purpose of reducing the weight of the power supply circuit, it may be possible to convert it into an optical frequency band by a radio wave / optical converter to form a power supply circuit by light.

Next, a second embodiment of the present invention will be described. FIG. 5 shows a configuration of a power feeding system which is a second embodiment of the present invention. Taking the case of transmission as an example, the configuration and operation of this power feeding system will be described. The antenna elements 401, 402, 403, 404 at the center of the cluster are respectively composed by combiners 263, 265, 267, 269.
And two amplifiers via the distributors 264, 266, 268, 270 (for the antenna element 401, the amplifier 251, 252, the antenna element
Amplifiers 253 and 254 are connected to 402, amplifiers 255 and 256 are connected to the antenna element 403, and amplifiers 257 and 258 are connected to the antenna element 404. In addition, the antenna elements 411 to 428 around the cluster have amplifiers 211 to 411, respectively.
228 are connected one by one. Here, it is assumed that the clusters are arranged as shown in FIG. The excitation power corresponding to each antenna element is set by the feeding circuits 89, 90, 91, 92 for each beam, and low side lobe radiation directivity is realized in each beam. Further, similar to the configuration example of FIG. 1, an antenna element shared between beams (clusters)
For 415,416,419,420,423,424, synthesizer 83,84,85,8
The signals are combined by 6,87,88.

The method of setting the maximum output power of the amplifier will be described below. Similar to the configuration example of FIG. 1, it is necessary to set an optimized excitation distribution for the antenna elements that form the cluster in order to reduce the side lobes. Here, the ratio of the power level excited to the antenna element at the center of the cluster and the power level excited to the antenna elements in the periphery is N: 1 (N is an integer). In the case of the cluster configuration of FIG.
If the power level excited to the surrounding antenna elements is about -3 dB with respect to the central element, this ratio will be 2: 1.
This ratio changes depending on the degree of side lobe reduction and the radiation directivity of the antenna element. In FIG. 5, the case where this ratio is 2: 1 is considered. In this case, in the embodiment of FIG. 1, the maximum output power of the amplifier connected to the central antenna element is set to N times that of the amplifier connected to the peripheral antenna elements, so that the power supply efficiency of the amplifier can be optimized. In the configuration example of FIG. 5, instead of multiplying the maximum output power by N, the same amplifiers connected to peripheral antenna elements are arranged in parallel. With such a configuration, exactly the same power supply efficiency as in the configuration example of FIG. 1 can be obtained,
A similar effect can be expected. In addition to this, it is possible to use all the same amplifiers.
Manufacturing and adjustment processes are further simplified, and there is an effect that it is very effective in reducing the cost of the entire antenna.

As described above, according to the above embodiment, since the antenna element and the amplifier are directly connected to each other, the P
It is easy to prevent the occurrence of problems such as IM and multipaction, and it is also effective in reducing loss. In addition, since the side lobes, which are important for effective frequency use in a multi-beam satellite communication system, are implemented in the power supply circuit that transmits low power signals, the optimum excitation distribution can be set for the antenna element. Easy to do. Further, since the isolation characteristic is not deteriorated, it is effective for use in a satellite broadcasting system or the like which requires high isolation characteristic for frequency reuse. Furthermore, by changing the shape of the antenna elements forming the cluster and changing the radiation directivity thereof, it is possible to set the combined radiation directivity to be optimum for high gain and low sidelobe. Since the optimum setting can be done here considering the power supply efficiency of the amplifier connected to each antenna element, when flexible correspondence such as changing the frequency band allocation is performed when the communication volume between beams changes. Moreover, the power supply efficiency of the amplifier can be used with high efficiency, which is extremely effective in a satellite-mounted system where the power supply is limited. Furthermore, the type of amplifier required to configure this antenna is only one type or at most two types, so the steps of designing, manufacturing, adjusting, etc. of this amplifier are greatly simplified.
It is possible to manufacture a product with good characteristics at low cost, and it is very effective for applications such as satellite mounted antennas.

[0030]

According to the present invention, problems such as power loss in high power transmission can be easily solved, the excitation distribution can be easily set for lowering side lobes, and the power source of the amplifier can be used with high efficiency. A multi-beam antenna having a feeding system can be provided.

[Brief description of drawings]

FIG. 1 is a top view showing a configuration of a primary radiator that is an embodiment of a multi-beam antenna of the present invention.

FIG. 2 is a diagram showing a configuration of a reflector antenna which is an embodiment of a multi-beam antenna of the present invention.

FIG. 3 is a diagram showing how beams are arranged and frequency division is performed.

FIG. 4 is a diagram showing a configuration of a feeding system that is a first embodiment of a multi-beam antenna of the present invention.

FIG. 5 is a diagram showing a configuration of a feeding system that is a second embodiment of the multi-beam antenna of the present invention.

FIG. 6 is a diagram showing a primary radiator configuration of a multi-beam antenna according to a conventional method.

FIG. 7 is a diagram showing a feed system configuration of a multi-beam antenna according to a conventional method.

FIG. 8 is a diagram showing another feed system configuration of a multi-beam antenna according to a conventional method.

FIG. 9 is a diagram showing another feed system configuration of a multi-beam antenna according to a conventional method.

[Explanation of symbols] 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,2
0,21,22,401,402,403,404,411,412,413,414,415,416,41
7,418,419,420,421,422,423,424,425,426,427,428… Antenna element, 24… Reflector, 23… Primary radiator, 31,32,33,3
4,501,502,503,504 ... Cluster, 47,48,49,50,89,90,9
1,92… Feed circuit, 55,56,57,58,61,62,63,64,65,66,67,
68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,101,1
02,103,104,201,202,203,204,211,212,213,214,215,21
6,217,218,219,220,221,222,223,224,225,226,227,228,
251,252,253,254,255,256,257,258… Amplifier, 205,206,
207,208,209,210… Splitter, 41,42,43,44,45,46,83,84,
85,86,87,88… combiner or distributor.

Claims (3)

[Claims] 1. A multi-beam antenna comprising a reflecting mirror and a primary radiator, wherein the primary radiator constitutes a cluster provided for each beam, and comprises a plurality of types having different radiation characteristics. A multi-beam antenna comprising: a plurality of antenna elements; and a plurality of amplifiers directly connected to each of the plurality of antenna elements. 2. The multi-beam antenna according to claim 1, wherein the ratio of the maximum output power of each of the plurality of amplifiers matches the ratio of the excitation power applied to the corresponding plurality of antenna elements. 3. The multi-beam antenna according to claim 1, wherein a ratio of excitation powers given to the plurality of antenna elements is represented by a specific integer ratio.