JP3457473B2 - Microwave transmitter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave transmitter for effectively cooling heat generated from a microwave power amplifier.

SUMMARY OF THE INVENTION The present invention is based on SNG (Satell).
The present invention relates to a microwave transmitter using a planar antenna of an array antenna type suitable for (ite News Gathering), and particularly to a cooling system for a microwave power amplifier. The microwave power amplifier needs to be provided in the immediate vicinity of the back surface of the planar antenna in terms of efficiency, and has a structure in which the microwave power amplifier, which is a heating element, is arranged near the center of the housing of the antenna unit. Therefore, conventionally, the microwave power amplifier is cooled by forcibly sucking air. In this structure, it is necessary to provide a space through which air can pass for cooling, which not only hinders the miniaturization of the antenna by making it large, but it also causes air containing salt when used at sea. Is also a factor that deteriorates the internal equipment and reduces the reliability of the device.

In the microwave transmitter according to the present invention, a well-known perforated flat tube formed by embedding a large number of thin tubes in a plate shape with the heat of the microwave power amplifier arranged immediately near the back surface of the planar antenna of the array antenna system. A heat pipe is used for transportation, and heat is dissipated by a radiator provided on the outer wall of the housing or outside the housing. According to the present invention, since the outside air does not flow directly into the housing, it is possible to reduce the size and weight of the microwave transmitter using the planar antenna of the array antenna system and to improve the reliability of the device.

[0004]

2. Description of the Related Art A microwave transmitter using an array antenna has many feeding points, and a microwave power amplifier is connected to each feeding point. In this case, in terms of microwave loss,
That is, in consideration of efficiency, it is necessary to attach a microwave power amplifier to the feeding point near the antenna.
Therefore, a large number of microwave power amplifiers are dispersedly arranged on the back surface of the antenna inside the housing. However, in this structure, heat is likely to be trapped particularly in the central portion of the housing, and therefore some cooling measure is required. However, in this case, since the microwave power amplifier generates a large amount of heat, it is not possible to rely on a heat transfer mechanism that depends only on the thermal conductivity of a metal such as copper or aluminum.

Therefore, conventionally, a space for cooling is provided in the housing, and the air is sucked into the housing by a fan for forced air cooling.

[0006]

However, in the above-mentioned conventional example, it is difficult to miniaturize the device because of the structure in which the space is provided inside the housing. Further, since forced air cooling for sucking air is adopted inside, when used at sea, etc., the equipment deteriorates due to salt damage, etc., causing a problem of reduced reliability.

As another cooling method, it is conceivable to circulate and cool the working fluid that transfers heat like a refrigerator or a car radiator, but this method requires a pump for circulating the working fluid. Therefore, it is difficult to reduce the size of a device that is important as a portable transmitter. Furthermore, in the conventional heat pipe that puts the working fluid in the pipe and absorbs the heat by the heat of vaporization to move the heat without a drive system, it is used on the earth where the positions of the heat generating part and the cooling part are affected by gravity. There was a limit to the attitude of time. This tendency is remarkable especially for heat pipes having a length exceeding 20 cm, which is not suitable for practical use.

The present invention has been made in view of the above circumstances, and an object thereof is to enable transmission without being influenced by the orientation direction of the antenna, to limit the place of use, and to reduce the size and weight. It is an object of the present invention to provide a microwave transmitter that is made possible and has excellent portability, as well as to provide a microwave transmitter that enhances the reliability of the device and can be operated even in a severe environment.

[0009]

In order to achieve the above object, the invention of claim 1 is a planar antenna of an array antenna system, and a micro antenna provided on the back side of the planar antenna and connected to the array antenna. Wave power amplifier, a large number of thin tubes are embedded in a plate shape, and a porous flat tube heat pipe to which the microwave power amplifier is attached, and a plurality of heat radiation fins are provided, and transmission is performed through the porous flat tube heat pipe. A radiator for dissipating the heat of the microwave power amplifier transported to the outside of the machine casing.

According to the above construction, the adoption of the perforated flat tube heat pipe makes it possible to cool the microwave power amplifier without being influenced by the orientation direction of the antenna unlike the conventional heat pipe. For this reason, it is possible to reduce the size and weight of the microwave transmitter, and it is possible to configure the microwave transmitter with excellent portability.
Further, since forced air cooling for sucking air into the housing is not adopted, it can be operated even in a severe environment such as at sea, and the reliability of the device can be improved.

According to a second aspect of the present invention, in the microwave transmitter according to the first aspect, the tip portion of the perforated flat tube heat pipe protruding outside the transmitter casing is bent along the outer wall of the transmitter casing. The radiator is attached to the bent portion.

According to the above construction, the heat transport characteristics between the perforated flat tube heat pipe and the radiator can be improved, and the heat radiation efficiency can be improved.

According to a third aspect of the invention, in the microwave transmitter according to the second aspect, an auxiliary perforated flat tube heat pipe formed in an inverted L shape is attached to the bent portion. is there.

According to the above construction, it is possible to improve the deterioration of the heat transport characteristics of the bent portion of the perforated flat tube heat pipe.

According to a fourth aspect of the present invention, in the microwave transmitter according to the first aspect, the radiator dissipates a plurality of heats by bending a tip portion of the perforated flat tube heat pipe protruding outside the transmitter casing. It is characterized in that it is formed by forming fins.

According to the above construction, since the radiator constituted by bending the perforated flat tube heat pipe to form a plurality of radiating fins is used, the heat conduction of the radiating fins is improved and the heat radiation is improved. Efficiency is improved. Therefore, when the heat generation amount is the same, the microwave transmitter can be downsized and lightened.

According to the invention of claim 5, claims 1 to 4
The microwave transmitter described above is characterized by comprising cooling means for cooling the radiator with water or air.

According to the above construction, since the radiator is cooled by water or air, the heat radiation efficiency can be further improved.

[0019]

DETAILED DESCRIPTION OF THE INVENTION

<First Embodiment> FIG. 1 is a perspective view showing the overall structure of a microwave transmitter according to the present invention. The microwave transmitter 1 includes a planar antenna 2 of an array antenna system composed of m × n array antennas (or sub-array antennas), and array antennas 3 constituting the planar antenna 2 in the vicinity of respective rear surfaces thereof. Of m × n microwave power amplifiers 4 connected to each array antenna 3, a porous flat tube heat pipe 5 to which the microwave power amplifier 4 is attached, and a porous flat tube heat pipe 5 to be attached. And the microwaves that are provided on the left and right side surfaces of the housing 6 and that have the circuit portion of the microwave transmitter 1 built therein and that are transported to the outside of the housing 6 through the perforated flat tube heat pipe 5. A radiator 8 that dissipates the heat of the power amplifier 4 from a plurality of radiator fins 7 and a fan 9 that is provided in each radiator 8 and sucks cooling air are provided. There is.

The perforated flat tube heat pipe 5 is also called a meandering thin tube heat pipe, and is formed by embedding a large number of thin tubes in a plate shape, and the inside thereof is evaporative like a normal heat pipe. The working fluid is sealed, and if there is a temperature difference between both ends of the flat tube, the working fluid evaporates in the high temperature part and flows to the low temperature part, radiating heat in this low temperature part and liquefying it I am trying.

However, in the thin tubes of the perforated flat tube heat pipe 5, the vapor phase liquid and the liquid phase liquid, which are vapor bubbles, are each formed into a plug shape due to the surface tension of the enclosed hydraulic liquid,
These are the inner diameters that are reduced in diameter so as to be able to vibrate in the axial direction while always keeping the state in which the inside of the tube is blocked. The inner diameter thereof is free from the wick (core for capillary action) that is present in ordinary heat pipes, and is formed smooth so that vibration is good.

The basic principle of heat transfer peculiar to the perforated flat tube heat pipe is heat transfer by axial vibration of the working fluid and its vapor bubbles. That is, the heat that is absorbed from the heat receiving portion due to vibration is transported to the cooling portion, and in the heat receiving portion, the liquid-phase working liquid that is randomly inside the heat pipe, rapidly generates many vapor bubbles due to the absorption of heat, Generate a pressure wave in the tube. The pressure waves are out of phase with each other and cancel each other or amplify each other to activate vibrations, resulting in heat transfer.

The portion of the perforated flat tube heat pipe 5 that is exposed to the outside of the housing 6 is sealed with a sealing material 10 to prevent outside air from entering the inside of the housing 6.

<Second Embodiment> FIGS. 2 to 4 show a second embodiment different from the first embodiment shown in FIG. 1 and a prototype thereof. The same reference numerals are given to the same member names as in FIG. The dimensions (unit: cm) of the main part are as shown.

The planar antenna 2 of the microwave transmitter 1 shown in each drawing has a size of 60 cm × 60 cm in length × width, and is composed of 16 (4 × 4) subarray antennas 3A having a size of 15 cm × 15 cm. It is configured. Power consumption of 25
About W, microwave power amplifier 4 with 5W microwave output
Is the number corresponding to the sub-array antenna 3A (16)
It is installed. Each microwave power amplifier 4 is firmly attached to the perforated flat tube heat pipe 5 via grease 11 having good thermal conductivity so as to reduce the thermal resistance.

The perforated flat tube heat pipe 5 has a width of 5 cm,
Eight pieces each having a length of 90 cm are used in total, two perforated flat tube heat pipes 5 are set as a set, and four microwave power amplifiers 4 are closely attached to each set. In addition, as shown in FIG. 4, about 15 cm at the tip of the perforated flat tube heat pipe 5 is bent 90 degrees along the side wall of the housing to form a bent portion 5A. The central 60 cm of the perforated flat tube heat pipe 5 is the housing 6
The inside of the housing and the outside of the housing are sealed with the sealing material 10 as described above so that the outside air does not enter the inside of the housing 6.

In the above structure, the heat generated by the microwave power amplifier 4 is conducted to the porous flat tube heat pipe 5 via the grease 11. Perforated flat tube heat pipe 5
Then, as described above, the working fluid inside is heated and evaporated, flows in the direction of the radiator 8 through the perforated flat tube heat pipe 5, is radiated by the radiator 8 and then is liquefied, and is again a high temperature portion of the micro. It is circulated in the vicinity of the mounting portion of the wave power amplifier 4. In the radiator 8, the air is sucked by the rotation of the fan 9 and the radiating fins 7 are cooled. In this way
The heat generated by the microwave power amplifier 4 is transported to the outside of the housing 6 through the perforated flat tube heat pipe 5 and radiated.

<< Experimental Example in Second Embodiment >> Second
An experimental example in the embodiment will be described with reference to FIGS. 5 and 6. This experimental example simulates 1/4 of the entire microwave transmitter 1 shown in the second embodiment. The dimensions (unit: cm) of the main part are as shown.

As shown in FIG. 5, a porous flat tube heat pipe 5 having a length of 90 cm, a width of 5 cm and a thickness of 0.19 c
Use two flat plates of m in parallel,
Bending by 5 cm to form a bent portion 5A, and each bent portion 5A
The radiator 8 was attached to each of these. Moreover, in order to simulate the microwave power amplifier 4 shown in FIG.
It was attached to the part corresponding to the attachment position of. further,
Temperature sensors t1, t for measuring the temperature of each heater 21
2, t4 and t5 were attached directly below the back surfaces of the four heaters, and temperature sensors t3 and t6 were also attached to the bent portions 5A at both ends of the porous flat tube heat pipe 5. The mounting interval of each of the temperature sensors t1 to t6 is about 14 cm. The radiator 8 was forcedly cooled by a fan.

In this state, changes in temperature were measured when the posture of the perforated flat tube heat pipe 5 was the following (a) to (d). (A) Horizontal, (b) 90 ° about the y-axis, (c) 90 ° about the x-axis, (d)
After rotating 45 degrees about the z-axis and then rotating 45 degrees about the x-axis (corresponding to the attitude of the planar antenna when SNG is used in Tokyo).

FIG. 7 shows the temperature change at the measurement point where the temperature rises most for each posture. As can be understood from FIG. 7, depending on the posture of the perforated flat tube heat pipe 5,
There was no significant change in properties that could not be used. That is, in this simulation, the maximum is 30
It has been shown that waste heat treatment can be performed even at a temperature rise of 100 degrees. As a result, it has been found that the microwave power amplifier 4 can perform heat dissipation processing regardless of the attitude of the antenna.

<Third Embodiment> FIGS. 8 and 9 are block diagrams showing a microwave transmitter according to a third embodiment of the present invention. The same members as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The feature of the third embodiment is that, instead of the radiator 8 shown in FIG. 1, the perforated flat tube heat pipe 5 for mounting the microwave power amplifier 4 as shown in FIG. A heat radiator 32 is configured by bending a tip portion protruding outside the housing to form a heat radiation fin 31. By configuring the radiator 32 with the perforated flat tube heat pipe as described above, the heat conduction of the radiation fins 31 is improved, and the radiation efficiency is increased. Therefore, when the amount of heat generation is the same, the microwave transmitter 1 can be made smaller and lighter.

<Fourth Embodiment> FIGS. 10 to 14
[Fig. 8] is a configuration diagram showing a fourth embodiment of a microwave transmitter according to the present invention. The same members as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The feature of the fourth embodiment is that, as shown in FIG. 11, a short auxiliary porous flat tube heat pipe 41 is closely attached to the bent portion 5A of the long porous flat tube heat pipe 5 to be used together. is there. With this auxiliary perforated flat tube heat pipe 41, the bent portion 5 of the perforated flat tube heat pipe 5
It is possible to improve the deterioration of the heat transport characteristics due to A.

<< Experimental Example in Fourth Embodiment >> FIGS. 12 and 13 show experimental examples in the fourth embodiment. As a perforated flat tube heat pipe 5, length 90 cm x width 5 c
Two flat plates having a size of m × 0.19 cm were used in parallel, and both ends were bent by 15 cm to form bent portions 5A, and the radiator 8 was attached to each bent portion 5A.

As the auxiliary porous flat tube heat pipe 41, four sheets each having a length of 30 cm were bent at the center and used, and were installed between the radiator 8 and the heater 21 adjacent to the radiator 8. Similar to the experimental example in the second embodiment, the heater 21 imitates the microwave power amplifier 4 and has the same shape and heat generation amount as the microwave power amplifier 4. In the experiment, the temperature rise ΔT from room temperature in the radiator 8 was measured for each attachment position of the heater 21. The attitude of the heat pipe is measured as an example when the heat pipe is rotated 45 degrees around the z axis and then rotated 45 degrees around the x axis (corresponding to the attitude of the planar antenna when SNG is used in Tokyo). did.

FIG. 14 shows the temperature change when only the perforated flat tube heat pipe 5 is used. As can be seen from the figure, it was confirmed that the temperature rise at the temperature sensor t4 was close to 35 ° C. in the transient period.

Next, FIG. 15 shows a temperature change when the auxiliary porous flat tube heat pipe 41 is used together. The temperature rise at this time was 25 ° C. or lower, and a margin of 10 ° C. or higher was secured. It was confirmed that an improvement of 5 ° C was achieved even in the steady state.

Next, the heater 2 is heated by the temperature sensor t4 in a structure in which the auxiliary porous flat tube heat pipe 41 is also used.
FIG. 16 shows the result of measuring the temperature characteristic by replacing 1 with the actual microwave power amplifier 4. The microwave power amplifier 4 to be mounted has a 4-stage FET configuration and has an output power of 5 W and an efficiency of 21%. The characteristics shown in the figure are the casings near the FETs of the input and output stages of the microwave power amplifier 4. It is a measurement result of temperature. As can be seen from the figure, it was confirmed that even in the actual microwave power amplifier 4 where the temperature distribution is not uniform, the temperature rise with respect to the ambient temperature can be suppressed to 25 ° C. or less.

[0041]

As described above, according to the first aspect of the invention, the heat of the microwave power amplifier arranged in the immediate vicinity of the back surface of the array antenna type planar antenna is formed by embedding a large number of thin tubes in a plate shape. Using the perforated flat tube heat pipe, the heat is dissipated by the radiator provided on the outer wall of the housing or outside the housing, so that the microwave power amplifier can be cooled without being affected by the orientation of the antenna. In addition, it is possible to reduce the size and weight of the microwave transmitter, which is excellent in portability. In addition, the reliability of the device can be improved, the device can be operated even under severe environment such as the sea, and the reliability of the device can be improved.

According to the second aspect of the present invention, the tip portion of the porous flat tube heat pipe protruding outside the transmitter housing is bent along the outer wall of the transmitter housing, and the radiator is attached to the bent portion. As a result, the heat transport characteristics between the perforated flat tube heat pipe and the radiator are improved, and the heat dissipation efficiency can be improved.

According to the third aspect of the invention, since the auxiliary flat flat tube heat pipe formed in an inverted L shape is attached to the bent portion at the tip of the flat flat tube heat pipe, the bent portion of the flat flat tube heat pipe is mounted. It is possible to improve deterioration of the heat transport characteristics of

According to the fourth aspect of the present invention, there is used a radiator in which a porous flat tube heat pipe is bent to form a plurality of radiating fins by bending a tip portion protruding outside the transmitter housing. Therefore, the heat conduction of the radiation fins will be good,
The heat dissipation efficiency is improved. Therefore, when the heat generation amount is the same, the microwave transmitter can be downsized and lightened.

According to the invention of claim 5, since the radiator is cooled by water or air, the heat radiation efficiency can be further improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an overall configuration of a first embodiment of a microwave transmitter according to the present invention.

FIG. 2 is a perspective view showing the overall configuration of a second embodiment of a microwave transmitter according to the present invention using 16 sub array antennas.

FIG. 3 is a plan view showing a configuration of a second embodiment of a microwave transmitter according to the present invention.

FIG. 4 is a side view showing the configuration of the second embodiment of the microwave transmitter according to the present invention.

FIG. 5 is a plan view showing a test apparatus simulating the configuration of the second embodiment.

FIG. 6 is a side view showing a test apparatus simulating the configuration of the second embodiment.

FIG. 7 is an explanatory diagram showing an experimental result of the second embodiment.

FIG. 8 is a perspective view showing an overall configuration of a third embodiment of a microwave transmitter according to the present invention.

FIG. 9 is a perspective view showing a configuration of a radiator used in the third embodiment.

FIG. 10 is a plan view showing a configuration of a fourth embodiment of a microwave transmitter according to the present invention.

FIG. 11 is a side view showing a configuration of a fourth embodiment of a microwave transmitter according to the present invention.

FIG. 12 is a plan view showing a test apparatus simulating the configuration of the fourth embodiment.

FIG. 13 is a side view showing a test apparatus simulating the configuration of the fourth embodiment.

FIG. 14 is an explanatory diagram showing experimental results of the fourth embodiment.

FIG. 15 is an explanatory diagram showing experimental results of the fourth embodiment.

FIG. 16 is an explanatory diagram showing experimental results of the fourth embodiment.

[Explanation of symbols]

1 microwave transmitter 2 planar antenna 3 array antenna 4 Microwave power amplifier 5 Perforated flat tube heat pipe 5A bend 6 housing 7,31 radiating fins 8,32 radiator 9 fans 10 Seal material 11 grease 21 heater 41 Auxiliary perforated flat tube heat pipe t1 to t6 temperature sensor

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-7-249937 (JP, A) JP-A-4-29416 (JP, A) JP-A-7-332883 (JP, A) JP-A-61-1 202772 (JP, A) Actual development 7-12771 (JP, U) Actual development 7-12770 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04B 1/036 H01Q 13 / 08 H01Q 21/08

Claims (5)

(57) [Claims] 1. An array antenna type planar antenna, a microwave power amplifier provided on the back side of the planar antenna and connected to the array antenna, and a plurality of thin tubes embedded in a plate shape. A heat dissipation device that includes a perforated flat tube heat pipe to which the microwave power amplifier is attached and a plurality of heat radiation fins, and dissipates the heat of the microwave power amplifier transported to the outside of the transmitter housing through the perforated flat tube heat pipe And a microwave transmitter. 2. The microwave transmitter according to claim 1, wherein a tip portion of the perforated flat tube heat pipe protruding outside the transmitter housing is bent along an outer wall of the transmitter housing, A microwave transmitter, wherein the radiator is attached. 3. The microwave transmitter according to claim 2, wherein an auxiliary perforated flat tube heat pipe formed in an inverted L shape is attached to the bent portion. 4. The microwave transmitter according to claim 1, wherein the radiator has a plurality of radiating fins formed by bending a tip portion of the perforated flat tube heat pipe protruding outside the transmitter housing. A microwave transmitter characterized by being configured. 5. The microwave transmitter according to claim 1, further comprising a cooling unit that cools the radiator with water or air.