JP7432631B2 - Antenna device and method for manufacturing the antenna device - Google Patents

Description

The present invention relates to an antenna device that connects a coaxial cable attached to a base part and a conductor pin provided in a waveguide inside the base part, and sends and receives electric power through the conductor pin to transmit and receive radio waves. The present invention relates to a manufacturing method, and particularly to an antenna device that exhibits stable and good performance in higher frequency bands by reliably fixing conductor pins at predetermined positions, and a manufacturing method thereof.

In recent years, with the development of multimedia, wireless terminals (smartphones, etc.) equipped with antennas for wireless communication such as cellular and wireless LAN have been actively produced. In the future, there will be a particular need for wireless terminals that can transmit and receive wireless signals compatible with IEEE802.11ad, 5G cellular, etc., which use wideband signals in the millimeter wave band.

In recent years, OTA (Over The Air) using a horn antenna such as a double-ridge horn antenna (DRHA) or a quad-ridge horn antenna (QRHA) has been used to test the performance of such wireless terminals. ) The test is about to take place. Patent Document 1 below discloses an invention of an antenna device that performs spurious measurements on wireless signals transmitted and received from an antenna under test using an anechoic box in an OTA environment.

In addition, conventionally, in the antenna feeding area (feed point) provided inside the ridge of horn antennas such as DRHA or QRHA, the impedance mismatch between the coaxial cable and the ridge is reduced. Attempts have been made to improve frequency characteristics in frequency bands. Patent Document 2 below discloses an invention of a horn antenna that can be used for OTA testing in an anechoic box and has an expanded operating frequency band by reducing impedance mismatch.

According to the horn antenna disclosed in Patent Document 2, as shown in FIG. It is possible to transmit and receive radio waves by coupling the waveguide with a conductor pin 370 and transmitting and receiving electric power using the conductor pin. This conductor pin 370 has one end fixed to the base portion 320 side, is further arranged to cross the waveguide of the power feeding area 380 through an insertion hole formed inside the base portion 320, and the other end is fixed to the base portion 320 side. is inserted into a notch 390 formed inside the base portion 320 on the side opposite to the insertion hole. According to this horn antenna, in order to reduce impedance mismatch, the diameter of the conductor pin 370 or the inner diameter of the insertion hole and notch portion 390 is structured to decrease as it approaches the tip of the conductor pin 370. There is.

JP 2021-60358 Publication Patent No. 5036772

When trying to realize the horn antenna disclosed in Patent Document 2 in the millimeter wave band with a short wavelength, in the manufacturing and assembly process, a thin conductor pin 370 of about 0.3 mm is inserted into an insertion hole with a relatively large inner diameter. At the same time, it is difficult in terms of processing technology and assembly technology to insert the tip into the notch part 390, which has a relatively small inner diameter, and to stably fix it in a constant state without contacting the insertion hole or the inner surface of the notch part 390. Therefore, even products with the same specifications could have variations in performance.

Patent Document 2 also discloses a structural example in which there is a gap between the conductor pin 370 and the inner surface of the insertion hole, but a dielectric material 400 is filled between the conductor pin 370 and the inner surface of the notch portion 390. has been done. Following such a structure example, a structure may be considered in which the notch portion 390 with a relatively small inner diameter is stuffed with a dielectric material as described above, and the tip of the conductor pin 370 is inserted and fixed therein, but an antenna with such a structure , it is difficult to stabilize the performance within the desired range. This is because, first, it is technically difficult to fill the notch portion 390, which has a relatively small inner diameter, with a dielectric material. Secondly, materials often used as dielectrics, such as PTFE (polytetrafluoroethylene, tetrafluoroethylene resin), often have large dimensional intersections as mechanical materials, and the notch portion 390 This is because it is difficult to provide a constant thickness between the conductor pin 370 and the notch portion 390 even if the conductor pin 370 and the notch portion 390 are packed together. In the invention of an antenna device, when the purpose is to obtain stable and good performance in a higher frequency band, the arrangement of the conductor pins that cross the waveguide, which is the feeding area of the antenna device, has minute dimensions. If it deviates from the expected value, there is a possibility that the performance of the antenna will vary, especially in the short wavelength band where the influence of minute capacitance is large.

The present invention has been made in view of the problems in the conventional technology described above, and it combines a coaxial cable attached to a base part and a conductor pin provided on a waveguide inside the base part, and connects this conductor. An antenna device that transmits and receives radio waves by transmitting and receiving power through pins, and its manufacture, which can exhibit stable and good performance in high frequency bands by securely fixing the conductor pin in a predetermined position. The purpose is to provide a method.

The antenna device 1 according to claim 1 includes:
a metal base portion 3 to which the coaxial cable is connected;
a waveguide 4 formed inside the base portion 3;
an insertion hole 15 formed inside the base part 3 so as to connect the coaxial cable connected to the base part 3 and the waveguide 4;
a receiving hole 16 opened in the waveguide 4 and formed inside the base portion 3 so as to be continuous with the insertion hole 15;
a conductor pin 13 whose base end is fixed to the base portion 3 so as to be electrically connected to the coaxial cable, and which is inserted into the insertion hole 15 with a gap therebetween and whose tip end is inserted into the receiving hole 16;
a fixing member 19 provided on the base portion 3 so as to fix the tip end of the conductor pin 13 within the receiving hole 16;
It is characterized by having the following.

The antenna device 1 according to claim 2 is the antenna device 1 according to claim 1, which includes:
The fixing member 19 is characterized in that it moves in a direction perpendicular to the longitudinal direction of the conductor pin 13 and presses the conductor pin 13.

The antenna device 1 according to claim 3 is the antenna device 1 according to claim 1 or 2, which includes:
The waveguide 4 is characterized in that a ridge 6 is provided.

The method for manufacturing the antenna device 1 according to claim 4 includes:
A base portion 3 made up of a plurality of structural members including a first structural member 2a formed with a receiving hole 16 and a second structural member 2b formed with an insertion hole 15 passing therethrough;
a coaxial connector 10 attached to the insertion hole 15 opened on the surface of the second structural member 2b;
a conductor pin 13 whose base end is attached to the coaxial connector 10 and inserted into the insertion hole 15 with a gap therebetween, and whose tip end is inserted into the receiving hole 16;
a fixing member 19 provided on the first structural member 2a so as to fix the tip of the conductor pin 13 within the receiving hole 16;
A method of manufacturing an antenna device 1 having the following steps:
inserting the conductor pin 13 into the receiving hole 16 opened in the first structural member 2a;
providing the fixing member 19 on the first structural member 2a to fix the conductor pin 13;
assembling the base portion 3 by combining the first structural member 2a and the second structural member 2b so that the conductor pin 13 passes through the insertion hole 15;
attaching the coaxial connector 10 to the insertion hole 15 opened in the second structural member 2b and the base end of the conductor pin 13;
It is characterized by comprising the following .

According to the antenna device described in claim 1, the conductor pin connecting the coaxial cable attached to the base portion and the waveguide inside the base portion is inserted through the insertion hole and arranged to cross the waveguide. At the same time, its tip is inserted into the receiving hole. On the other hand, the fixing member provided on the base presses the tip of the conductor pin inserted into the receiving hole, so the position of the conductor pin inside the insertion hole and inside the receiving hole is fixed and changes. Never. For this reason, the antenna device can demonstrate stable and good performance in higher frequency bands compared to antenna devices without fixed conductor pins, and there may be variations in performance if the products have the same specifications. do not have.

According to the antenna device described in claim 2, since the fixing member presses the conductor pin in a direction perpendicular to the longitudinal direction of the conductor pin, the conductor pin in the receiving hole is approximately parallel to the inner surface of the receiving hole. surface contact with the inner surface of the receiving hole while maintaining the same condition. Therefore, the position of the conductor pin inside the receiving hole and the position of the conductor pin inside the insertion hole are stably fixed and do not change, and the antenna device can exhibit a predetermined performance.

According to the antenna device according to claim 3, since the waveguide is provided with a ridge, stable and good performance can be obtained in a wider frequency band, particularly in a high frequency band, than in a case where the waveguide is not provided with a ridge. Can be done.

According to the method for manufacturing an antenna device according to claim 4, the conductor pin is inserted into the receiving hole of the first structural member and fixed by the fixing member, and then the conductor pin is inserted into the receiving hole of the first structural member, and then the conductor pin is inserted into the receiving hole of the first structural member. A base portion is assembled by combining the first structural member and the second structural member, and finally, a coaxial connector is attached to the insertion hole opened in the surface of the second structural member and the base end of the conductor pin. According to this assembly method, the conductor pins are assembled first, and the conductor pins attached to the coaxial connector are inserted into the insertion holes from the outside of the base, and then inserted into the receiving holes that cannot be seen visually. The pins are easy to handle, the work is simple, and the assembly accuracy is high.

FIG. 1 is an external perspective view of an antenna device according to an embodiment. FIG. 3 is a cross-sectional view taken along a vertical plane that passes through the center of the coaxial connector on the top surface and is parallel to the long side of the base in the antenna device of the embodiment. It is a figure which shows the photograph of the components which constitute the coaxial connector used for the antenna device of embodiment. 3 is an enlarged view of section A in FIG. 2. FIG. It is a flow chart showing a manufacturing process of an antenna device of an embodiment. FIG. 2 is a graph comparing the input voltage standing wave ratio (VSWR) of the antenna device of the embodiment and the input voltage standing wave ratio (VSWR) of the antenna device of the comparative example.

Embodiments of the antenna device according to the present invention will be described below with reference to FIGS. 1 to 5. Note that the dimensional ratio of each component on each drawing does not necessarily match the actual dimensional ratio.

First, the structure of the antenna device 1 of the embodiment will be mainly described.
As shown in FIGS. 1 and 2, the antenna device 1 of the embodiment includes a metal base portion 3 assembled into a substantially box shape from a plurality of structural members 2 (2a, 2b). A waveguide 4 through which electromagnetic waves are transmitted is formed inside the base portion 3 . The waveguide 4 is continuous with a horn portion 5 whose diameter increases toward the front of the base portion 3, and the horn portion 5 is open at the front surface of the base portion 3.

As shown in FIGS. 1 and 2, four ridges 6 are formed on the inner surface of the horn section 5 from the waveguide 4 of the base section 3 toward the opening of the horn section 5. By providing the ridge 6, the antenna device 1 of the embodiment can obtain stable and good performance in a wider frequency band, particularly in a high frequency band, compared to a case where the ridge 6 is not provided. Note that there is no reason to limit the number of ridges 6 to four, and it may be one or two.

As shown in FIG. 2, the waveguide 4 communicates with a substantially rectangular parallelepiped-shaped cavity 7 that is opened at the rear surface of the base portion 3. As shown in FIG. The cavity 7 is closed by a closing part 8. The closing part 8 has an outer shape that substantially matches the inner shape of the cavity 7, but has a slightly smaller dimension in the longitudinal direction than the cavity 7, and has a predetermined volume in the front part of the cavity 7 that communicates with the waveguide 4. It is divided into This cavity 7 provides a shunt inductance at the rear of the waveguide 4 that serves as the power feeding region of the antenna device 1, and matches the impedance to prevent energy from being radiated to the rear of the antenna device 1. Note that a flange portion 9 is provided at the rear end of the closing portion 8. By connecting the flange portion 9 to the base portion 3 using a fixing means (not shown), the closing portion 8 can be held within the cavity 7 and the front portion of the cavity 7 can be partitioned into a predetermined volume. Furthermore, as can be understood from the shape of the flange portion 9 shown in FIG. 1, the antenna device 1 can be connected and fixed to other devices, frames, etc. by the flange portion 9 and fixing means (not shown).

As shown in FIGS. 1 and 2, a coaxial connector 10 is attached to the top and side surfaces of the base portion 3, and a coaxial cable (not shown) can be connected to the base portion 3 via the coaxial connector 10. . FIG. 3 is a diagram for explaining the structure of the coaxial connector 10, and shows a photograph of an example of parts constituting the coaxial connector 10. As shown in FIG. 3, the coaxial connector 10 includes a metal shell 11 that is a substantially cylindrical body provided with a flange 11a for attachment to the base portion 3, and contacts 12 housed inside the shell 11. A metal conductor pin 13 protruding toward the base portion 3 can be attached to the contact 12. The contact 12 is a substantially cylindrical member, and includes a center conductor 12a and a cylindrical outer conductor 12b surrounding the center conductor 12a, and the conductor pin 13 is connected to the center conductor 12a of the contact 12. Although not shown, the coaxial connector 10 includes a center conductor and an outer conductor, and when a coaxial cable is connected to the coaxial connector 10, the center conductor of the coaxial cable and the center conductor 12a of the coaxial connector 10 are electrically connected. Ru.

FIG. 4 is an enlarged view of section A surrounded by a bold line in FIG. As shown in FIG. 4, an insertion hole 15 is formed inside the base portion 3, through which a conductor pin 13 connected to the center conductor 12a of the coaxial connector 10 attached to the base portion 3 is inserted. The insertion hole 15 is a hole with a circular cross section orthogonal to the direction of the waveguide 4, and connects the gap between the center conductor 12a and the outer conductor 12b of the coaxial connector 10 and the waveguide 4 near the cavity 7. The inner diameter of the insertion hole 15 is larger than the conductor pin 13, and when the conductor pin 13 is inserted into the insertion hole 15, the conductor pin 13 is arranged at the center of the insertion hole 15 with its axis aligned with the insertion hole 15, and the conductor pin 13 There is a dielectric layer of air around it with a certain thickness, which functions as a coaxial line.

As shown in FIG. 4, a receiving hole 16 is formed at the other end of the insertion hole 15 of the base portion 3 so as to be continuous with the insertion hole 15 by aligning the center axes with each other and open into the waveguide 4. There is. The inner diameter of the receiving hole 16 is large enough to allow the conductor pin 13 to be inserted without experiencing large resistance. Therefore, when the conductor pin 13 is inserted into the receiving hole 16, the circumferential surface of the conductor pin 13 and the inside of the receiving hole 16 are connected. The peripheral surfaces are almost in surface contact. Further, the length of the receiving hole 16 is such that the tip of the conductor pin 13 contacts the bottom of the receiving hole 16 when the antenna device 1 is assembled.

As shown in FIG. 2, an insertion hole 17 is formed on the rear surface of the base portion 3 in a direction perpendicular to the longitudinal direction of the receiving hole 16 or the conductor pin 13, and further inside the insertion hole 17, A screw hole 18 coaxially continuous with the insertion hole 17 is formed. The screw hole 18 opens into the receiving hole 16. As shown in FIGS. 2 and 4, a set screw 19 is screwed into the screw hole 18 as a fixing member for the conductor pin 13. is pressing down. Since the set screw 19 presses the conductor pin 13 in a direction perpendicular to the longitudinal direction of the conductor pin 13, the conductor pin 13 in the receiving hole 16 maintains a state substantially parallel to the inner surface of the receiving hole 16. The surface contacts the inner surface of the receiving hole 16. Therefore, the position of the conductor pin 13 inside the receiving hole 16 and the position of the conductor pin 13 inside the insertion hole 15 are stably fixed and do not change, and the antenna device 1 can exhibit a predetermined performance. Can be done.

The operation of increasing or decreasing the pressing force by turning the set screw 19 is performed by inserting a tool such as a screwdriver through the insertion hole 17. Normally, the closing part 8 is inserted into the cavity 7 of the base part 3, and the rear surface of the base part 3 is covered by the flange part 9, so the insertion hole 17 is not visible from the outside and cannot be accessed. I can't. Therefore, after properly adjusting the holding state of the conductor pin 13 with the set screw 19, the closing part 8 and the flange part 9 are attached to the base part 3 to prevent the set screw 19 from being manipulated intentionally or accidentally. The original performance of the device 1 can be guaranteed.

Next, a method (process) for manufacturing the antenna device 1 of the embodiment will be described with reference to FIGS. 2 and 4. The base portion 3 of this antenna device 1 is assembled from a plurality of structural members. Among the structures, the lower structural member in particular is referred to as a first structural member 2a, and the upper structural member is referred to as a second structural member. It is called a structural member 2b. Another structural member disposed between the first structural member 2a and the second structural member 2b is designated by the reference numeral 2 as an intermediate structural member.

First, before assembling the base part 3 into a substantially box shape, the conductor pin 13 is inserted into the receiving hole 16 opened in the lower first structural member 2a that constitutes the lower half of the base part 3 ( FIG. 4, step S1).

Next, insert the set screw 19 through the insertion hole 17 on the rear surface of the lower first structural member 2a, screw the set screw 19 into the deep screw hole 18, and press the conductor pin 13 with the tip of the set screw 19. Fix it (FIG. 4, step S2).

Next, the intermediate structural member 2 is assembled on top of the lower first structural member 2a, and the upper second structural member 2b is lowered so that the upper half of the conductor pin 13 passes through the insertion hole 15. The plurality of structural members 2a, 2b, 2 are fixed to each other by covering the first structural member 2a on the side, and the base portion 3 is assembled (FIG. 4, step S3).

Finally, the coaxial connector 10 is attached to the insertion hole 15 opened in the upper second structural member 2b and the conductor pin 13 protruding from the insertion hole 15 (FIG. 4, step S4).

In the antenna device of the embodiment, the base portion 3 is assembled first, and the conductor pins 13 are attached to the coaxial connector 10, so that the conductor pins 13 attached to the coaxial connector 10 cannot be visually recognized from the outside of the base portion 3 through the insertion hole 15. It can also be manufactured by inserting it into the receiving hole 16. However, according to the manufacturing method (process) of the embodiment described above, the conductor pin 13 is inserted into the receiving hole 16 of the first structural member 2a, and then the base part 3 is assembled, and the coaxial connector 10 is attached to the base part 3. Since the conductor pins are attached last, it is easy to handle the conductor pins, the work is simple, and the assembly accuracy is high.

Next, the functions and effects of the antenna device 1 of the embodiment will be explained.
According to the antenna device 1 configured as described above, when a high frequency signal is fed to the conductor pin 13 via a coaxial cable (not shown), a high frequency voltage is applied between the conductor pin 13 and the base portion 3, Radio waves of high frequency signals are radiated to the outside. Moreover, when a radio wave is input into the waveguide 4 from the outside, it is received by the conductor pin 13, and the received radio wave is output toward the coaxial cable.

FIG. 5 is a graph comparing the input voltage standing wave ratio (VSWR) of the antenna device 1 of the embodiment and the input voltage standing wave ratio of the antenna device 1 of the comparative example. be. The input voltage standing wave ratio represents how much of the power incident on the input port of the antenna device 1 is reflected in the operation of the antenna device 1 described above, and a small value of the input voltage standing wave ratio means that the antenna This shows that the performance of device 1 is good. Note that the antenna device of the comparative example has a power feeding structure similar to that of Patent Document 2, and a base portion having the same configuration as antenna device 1.

As shown in FIG. 5, the input voltage standing wave ratio of the antenna device 1 of the embodiment shows a generally lower value in a frequency band higher than 27 GHz compared to the antenna device of the comparative example. In particular, the antenna device 1 of the embodiment shows an input voltage standing wave ratio that is several times better than that of the antenna device 1 of the comparative example in a frequency band higher than 35 GHz, and is compatible with IEEE802.11ad, 5G cellular, etc. When it is assumed that the antenna device 1 of the embodiment is applied to a wireless terminal that uses wideband wireless signals in the millimeter wave band compatible with It is shown that there is.

The antenna device 1 of the embodiment described above has a configuration in which a waveguide 4 in which a conductor pin 13 is arranged, a ridge 6 and a horn portion 5 that are continuous with the waveguide 4 are provided in the base portion 3, and even this alone can generate radio waves. In the OTA (Over The Air) test using the anechoic box described above, it can be used as an antenna device, etc. to perform spurious measurements on the wireless signals transmitted and received from the antenna under test. can. However, considering the antenna device 1 of the embodiment as a converter for electromagnetic waves and electric power, it is also possible to attach a horn antenna as a separate member to the opening of the horn portion 5 and use the antenna device as a whole as an antenna.

1... Antenna device 2... Structural member 2a... First structural member 2b... Second structural member 3... Base portion 4... Waveguide 6... Ridge 10... Coaxial connector 13... Conductor pin 15... Insertion hole 16... Receiving hole 19 ...Set screw as a fixing member

Claims (4)

a metal base portion (3) to which the coaxial cable is connected;
a waveguide (4) formed inside the base portion;
an insertion hole (15) formed inside the base to connect the coaxial cable connected to the base and the waveguide;
a receiving hole (16) opened in the waveguide and formed inside the base portion so as to be continuous with the insertion hole;
a conductor pin (13) whose base end is fixed to the base part so as to be electrically connected to the coaxial cable, and which is inserted into the insertion hole with a gap and whose tip end is inserted into the receiving hole;
a fixing member (19) provided on the base portion so as to fix the tip of the conductor pin within the receiving hole;
An antenna device (1) characterized by having: The antenna device (1) according to claim 1, wherein the fixing member (19) moves in a direction perpendicular to the longitudinal direction of the conductor pin (13) and presses the conductor pin. The antenna device (1) according to claim 1 or 2, wherein the waveguide (4) is provided with a ridge (6). Consisting of a plurality of structural members including a first structural member (2a) formed with a receiving hole (16) and a second structural member (2b) formed with an insertion hole (15) passing through it. a base portion (3),
a coaxial connector (10) attached to the insertion hole opened in the surface of the second structural member ;
a conductor pin (13) whose base end is attached to the coaxial connector and inserted into the insertion hole with a gap therebetween, and whose tip end is inserted into the receiving hole;
a fixing member (19) provided on the first structural member so as to fix the tip of the conductor pin within the receiving hole;
A method for manufacturing an antenna device (1) comprising:
inserting the conductor pin into the receiving hole opened in the first structural member;
providing the fixing member on the first structural member to fix the conductor pin;
assembling a base portion by combining the first structural member and the second structural member so that the conductor pin passes through the insertion hole;
attaching the coaxial connector to the insertion hole opened in the second structural member and the base end of the conductor pin;
A method of manufacturing an antenna device, comprising:

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