JP4535651B2 - Stack antenna structure - Google Patents

Description

[0001]
The present invention relates to a stack antenna structure, and more particularly to a stack antenna structure suitable for mounting on a rocket by combining a waveguide antenna and a blade antenna.
[Prior art]
The rocket-mounted antenna is mounted at a position around the rocket where the ground station's radio link is in good condition, but the range of the optimal mounting position of the antenna is also narrowed due to the narrower coverage due to the larger rocket It has become.
[0002]
Among the rocket-mounted antennas, two types of antennas, the basic telemeter system (mainly using the S band) and the tracking system (mainly using the C band), are the ground station that is the communication partner of the rocket and these two types When viewed from the rocket, the relationship with the antenna is the same direction, so that the optimum mounting position of the basic telemeter system mounting blade antenna and the tracking system mounting waveguide antenna is the same. However, it is difficult to attach the blade antenna and the waveguide antenna at the same position, and therefore it is unavoidable to place both antennas at positions adjacent to each other.
[0003]
FIG. 8 shows the structure of a conventional blade antenna (S band), and FIG. 9 shows the structure of a conventional waveguide antenna (C band). Referring to FIG. 8, reference numeral 101 denotes a blade antenna mounting base, reference numeral 102 denotes a radiating element of the blade antenna, reference numeral 103 denotes a central conductor thereof, and reference numeral 104 denotes a feeding portion of the blade antenna. Referring to FIG. 9, reference numeral 201 denotes a waveguide, 202 denotes a central conductor, and 203 denotes a power feeding portion thereof. These two individual antennas shown in FIGS. 8 and 9 are attached to adjacent positions around the rocket.
[0004]
[Problems to be solved by the invention]
When attaching these two types of antennas to the rocket, as described above, since there is only one optimal mounting position, two types of antennas cannot be attached to this single location. There is a problem that the antenna and the waveguide antenna must be arranged next to each other.
[0005]
Japanese Patent Laid-Open No. 6-350322 discloses a technique in which two types of antenna elements 4 and 5 have a stack structure and the feeding portions of these two types of antennas have a coaxial structure. FIG. 10 is a diagram showing a cross-sectional structure of the antenna disclosed in this publication.
[0006]
Referring to FIG. 10, a double coaxial line is provided through the ground conductor layer G, and the center conductor 1 is connected to the center point of the upper antenna element 4 in the plural transmission / reception antennas, for example, a capacitor antenna made of a conductor disk. At the same time, the outer conductor 2 is coaxially connected to the lower antenna element 5, for example, a central portion of a capacitor antenna which is also formed of a conductor disk.
[0007]
Therefore, in such a connection state, for example, if the central conductor 1 is connected to the output of the transmitter and the outer conductor 2 is connected to the input of the receiver, separate antenna elements can be used for transmission and reception. At this time, it is necessary to provide means for separating the transmission wave and the reception wave. For this purpose, the center conductor 6 of another coaxial line led from the side of the double coaxial line through the ground conductor layer is connected to the outer conductor 2 of the double coaxial line, and the double coaxial is connected from the connection point. The outer conductor 2 is short-circuited to the outer conductor 3 at a point separated from the antenna by a quarter wavelength of the signal wave received by the lower antenna element 5 via the outer conductor 2 in the direction opposite to the antenna.
[0008]
Therefore, the received wave propagating through the outer conductor 2 is reflected at the short-circuited point and returned to the connection point in reverse phase to be canceled out. From the connection point, it propagates through the center conductor 6 of another coaxial line, and both waves of transmission and reception are separated from each other, and transmitted through the matching element and the transmission / reception separation filter connected to the center conductors 1 and 6 respectively. The machine and the receiver will be reached independently.
[0009]
In FIG. 10, (1) indicates the power feeding unit input of the antenna element 4, and (2) indicates the power feeding unit input of the antenna element 5.
[0010]
In the technique of attaching the feeding parts of the conventional two types of antennas shown in FIG. 10 in the same place as a coaxial structure, this impedance matching is necessary even though adjustment is required for impedance matching of the antenna. There is no consideration for the function, and thus the impedance of the antenna cannot be adjusted. There is a problem that even if the feeding parts of the two types of antennas have a coaxial structure and the two types of antennas can be installed at the same location, impedance matching cannot be performed, so that an optimal radio wave state cannot be obtained.
[0011]
An object of the present invention is to provide a stack antenna structure in which two types of antennas can be attached at the same place and impedance matching is also possible.
[0012]
[Means for Solving the Problems]
According to the present invention, a waveguide antenna, a blade antenna attached to the top surface of the waveguide antenna, and a central conductor of the blade antenna for feeding power to both antennas are guided by the waveguide. A feed portion having a coaxial structure surrounded by a central conductor of a tube antenna, and a variable insertion length mechanism for changing the insertion length of the central conductor into the waveguide of the waveguide antenna. A stack antenna structure is obtained.
[0013]
The insertion length variable mechanism is characterized in that an outer peripheral portion of the coaxial structure is a screw structure, and the insertion length is adjusted by the screw structure to achieve impedance matching, and the waveguide antenna The distance L from the closed surface of the waveguide to the position of the feeding portion is as follows. When the wavelengths of the waveguide antenna and the blade antenna are λ1 and λ2,
L = (2m + 1) λ1 / 4 = nλ2 / 2 (n and m are natural numbers)
It is characterized by being set to a relationship.
[0014]
In addition, the blade antenna has a connector jack mechanism for maintaining contact between the center conductor and the radiating element of the blade antenna in response to movement of the center conductor of the blade antenna by the insertion length variable mechanism. It is said.
[0015]
The operation of the present invention will be described. A stack structure in which a blade antenna is attached to the upper surface portion of a conductor tube type antenna, and the feeding portion of these two types of antennas has a double coaxial structure, so that the feeding positions of both antennas can be made one place. At the same time, the insertion length (to the waveguide portion) of the central conductor of the waveguide antenna is configured to be variable by using a screw structure so that impedance matching can be achieved.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing an appearance of an embodiment of the present invention, and is a top view, a side view, and a rear view. As shown in FIG. 1, a blade antenna 20 is stacked on top of a waveguide antenna 10, and the upper surface of the waveguide 11 of the waveguide antenna 10 and the mounting base of the blade antenna 20 are shared. It has become. In addition, as shown in the cross-sectional structure of FIG.
[0017]
That is, the central conductor c of the blade antenna 20 is surrounded by the central conductor d of the waveguide antenna 10, and a dielectric (insulator) indicated by hatching is provided between the central conductors c and d. ing. In all the figures, hatching indicates a dielectric. In FIGS. 1 and 2, b indicates a power feeding unit input of the waveguide antenna 10, and a indicates a power feeding unit input of the blade antenna 20.
[0018]
FIG. 3 is a cross-sectional view showing details of the coaxial structure 30. The center conductor d has a screw structure e at the outer periphery thereof, and the entire coaxial structure 30 moves up and down as indicated by an arrow B by rotating the center conductor d of the screw structure as indicated by an arrow A. Therefore, the insertion length of the central conductor d with respect to the waveguide 11 is varied, and the impedance matching function can be achieved.
[0019]
Here, when the insertion length of the center conductor d of the waveguide antenna is changed, the insertion length of the center conductor c in the upper blade antenna is also changed. In order to cope with the change in the insertion length of the center conductor c, as shown in FIG. 4, in the radiating element s on the blade antenna side, a hole that can accommodate the vertical movement (arrow B) is provided. In this hole, a connector jack (brush) f is attached. The center conductor c is inserted into the connector jack f, and is moved up and down in this state, so that the center conductor c comes into contact with the connector jack f while being oscillated and can be electrically connected to the heat radiating element s. It has become.
[0020]
By doing so, it is possible to cope with a change in the insertion length of the central conductor c of the blade antenna. Note that the insertion length of the central conductor c of the blade antenna does not affect the electrical characteristics of the blade antenna.
[0021]
FIG. 5 is a diagram showing the impedance matching function of the blade antenna. For impedance matching, a short member (short-circuit member) i that adjusts the length (λ 2/4) of the radiation surface in the radiating element s is provided, and the position (ie, short-circuit position) g of the short member i is adjusted. Therefore, impedance matching is intended. In order to adjust the position of the short member i, a screw structure h for moving the short member i in the direction of the arrow D is provided, and the screw structure h is rotated as shown by the arrow E so that the adjustment is possible. Become.
[0022]
In addition, since the short member i is connected to the screw structure h through the retainer ring j, the short member i is not rotated by the rotation of the screw structure h. In addition, since the short member i slides in the direction of the arrow D, a short circuit is ensured by using the conductive elastic brush k.
[0023]
FIG. 6 is a diagram for explaining the position of the power feeding unit having the coaxial structure 30. The distance L from the closed surface of the waveguide 11 of the feeding parts of the frequencies f1 (waveguide antenna) and f2 (blade antenna) of the two types of antennas is selected according to the following equation. That is, when the signal wavelength in the waveguide of the waveguide antenna is λ1, and the signal wavelength in the waveguide of the blade antenna is λ2, m and n are natural numbers.
L = (2m + 1) λ1 / 4 = nλ2 / 2
It is determined by the following relational expression.
[0024]
By doing so, the distribution of both signals inside the waveguide 11 becomes as shown by the solid line λ1 and the broken line λ2, and the feed signal to the waveguide antenna has the maximum amplitude at the position of the central conductor d. Conversely, the signal of the blade antenna has the minimum amplitude, and the signal of frequency f1 is fed to the waveguide antenna, but the signal of frequency f2 is not fed.
[0025]
FIG. 7 is a cross-sectional view showing another example of the impedance matching mechanism of the waveguide antenna. The insertion length of the center conductor d into the waveguide 11 is changed by the screw structure e of the center conductor d and the screw structure l of the dielectric. The center conductor m at the end of the power feeding portion input b of the lower waveguide antenna has a function of always contacting the screw portion e of the center conductor d. A spring o is provided between the center conductors m and n, and the conductor m is in contact with the screw portion e of the center conductor d at a point p by the spring force of the spring.
[0026]
In order to prevent the center conductor m from being pressed against the contact point p due to the spring force of the spring o and the insertion length of the center conductor d from being changed, a step q is provided in the center conductor m. Further, the center conductor n is fixed with an adhesive r so that the center conductor n does not jump out from the end of the power feeding section input b.
[0027]
【The invention's effect】
As described above, according to the present invention, the waveguide type antenna and the blade antenna are stacked and the feeding part has a coaxial structure, so that the feeding position of both antennas can be made one place. In the case of mounting on the antenna, there is an effect that it is possible to attach the waveguide type antenna and the blade antenna to the same optimum mounting phase location. Further, since the insertion length of the center conductor is variably adjusted so that it can move up and down in the coaxial structure of the power feeding section, there is an effect that impedance matching is facilitated.
[Brief description of the drawings]
FIG. 1 is a diagram showing an external appearance of an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a double coaxial structure of a power feeding unit in an embodiment of the present invention.
FIG. 3 is a cross-sectional view of an impedance matching mechanism of a waveguide antenna according to an embodiment of the present invention.
FIG. 4 is a cross-sectional view of a mechanism corresponding to a change in insertion length of a central conductor for a blade antenna in an embodiment of the present invention.
FIG. 5 is a diagram illustrating an example of an impedance matching mechanism of a blade antenna in an embodiment of the present invention.
FIG. 6 is a diagram for explaining a feeding position relationship between two signal frequencies in the embodiment of the present invention. FIG. 7 is a diagram showing another example of the impedance matching mechanism of the waveguide antenna in the embodiment of the present invention. It is.
FIG. 8 is a diagram showing an example of a blade antenna (S band).
FIG. 9 is a diagram illustrating an example of a waveguide antenna.
FIG. 10 is a diagram showing an example of an antenna structure having a conventional coaxial power feeding mechanism.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Waveguide type antenna 11 Waveguide 20 Blade antenna 30 Feed part a Blade antenna feed part input b Waveguide type antenna feed part c Blade antenna center conductor d Waveguide type antenna center conductor e Screw Structure f Connector jack (brush)
g Short position of blade antenna i Short member of blade antenna s Blade antenna radiating element

Claims (4)

A waveguide antenna, a blade antenna mounted on the top surface of the waveguide antenna, and a central conductor of the waveguide antenna for feeding power to both antennas. A stack antenna structure, comprising: a coaxial power supply section surrounded by an antenna; and a variable insertion length mechanism that allows a variable insertion length of the central conductor to the waveguide of the waveguide antenna. 2. The stack antenna structure according to claim 1, wherein the insertion length variable mechanism is configured such that an outer peripheral portion of the coaxial structure is a screw structure, and the insertion length is adjusted by the screw structure to achieve impedance matching. The distance L from the waveguide blocking surface of the waveguide type antenna to the position of the power feeding portion is set such that each signal wavelength of the waveguide type antenna and the blade antenna is λ1 and λ2.
L = (2m + 1) λ1 / 4 = nλ2 / 2 (n and m are natural numbers)
The stack antenna structure according to claim 1, wherein the stack antenna structure is set to satisfy the following relationship. Corresponding to the center conductor of the blade antenna moving by the insertion length variable mechanism, the blade antenna has a connector jack mechanism for maintaining contact between the center conductor and the radiating element of the blade antenna. The stack antenna structure according to claim 1.

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