Compact mobile body

Abstract

The present disclosure relates to a compact mobile body. This compact mobile body is provided with a wireless communication device and a dipole antenna in which two antenna elements are fixed so as to form 180 degrees.

Description

small mobile object

[0001] The present disclosure relates to small vehicles.

[0002] Patent Literature 1 discloses a technology using a drone equipped with a wireless communication device. Thus, there is a demand for a wireless communication device to be equipped on a small mobile object. The small mobile object is, for example, a motorcycle, a small passenger car, or a small flying object such as a drone.

[0003] Furthermore, Patent Document 2 discloses a technology for mounting a wireless communication device using a monopole antenna on a drone. A monopole antenna operates by grounding one end of the antenna, and is therefore smaller than other antennas. Therefore, when mounting a wireless communication device on a small mobile object with limited mounting space, a monopole antenna is often used, particularly for transmitting and receiving radio waves at frequencies such as the HF band.

[0004] Kohei Kawabata; Hiroyuki Arai, “Wind Influence of Air Wire Antenna Suspended from Drone”, 2018 International Symposium on Antennas and Propagation, October 2018.Koki Ito, Katsuyuki Fujii, Yasuyuki Okumura, Masahiro Umehira, “Effect of Unmanned Aerial Vehicles for Electromagnetic Field Measurement on Near Field of “High-frequency-Band Monopole Antennas”, 2023 IEEE 12th Global Conference on Consumer Electronics, October 2023.

[0005] However, because small mobile devices have limited mounting space, wireless communication devices mounted on small mobile devices are often installed near electronic devices that emit electromagnetic noise. This means that the level of noise entering the received signal at the antenna is high. As a result, wireless communication quality using wireless communication devices mounted on small mobile devices is prone to degradation.

[0006] In particular, to transmit and receive relatively low-frequency radio waves, such as in the HF band, a large conductive plate is required as a ground. Monopole antennas mounted on small mobile objects cannot accommodate large conductive plates in the small mounting space, making it difficult to obtain a stable grounding environment. As a result, wireless communications using monopole antennas have the problem of further deterioration in communication quality.

[0007] In order to solve the above-mentioned problems, the present disclosure aims to provide a small mobile object capable of improving the communication quality of the wireless communication device mounted thereon.

[0008] An aspect of the present disclosure is preferably a small mobile object including a wireless communication device and a dipole antenna in which two antenna elements are fixed at an angle of 180 degrees.

[0009] According to the aspects of the present disclosure, the communication quality of the wireless communication device equipped therewith can be improved.

[0010] FIG. 1 is a diagram showing a small mobile body according to a first embodiment of the present disclosure; FIG. 2 is a block diagram showing a configuration example of a small mobile body according to a first embodiment of the present disclosure; FIG. 3 is a diagram showing an example of use of a monopole antenna; FIG. 4 is a diagram showing a small mobile body according to a first comparative example; FIG. 5 is a block diagram showing a configuration example of a small mobile body according to a first comparative example; FIG. 6 is a diagram showing interference with wireless communication of a monopole antenna according to a first comparative example; FIG. 7 is a diagram showing a small mobile body according to a second comparative example; and FIG. 8 is a diagram showing a small mobile body according to a third comparative example.

[0011] Embodiment 1 [Configuration of a Small Mobile Body According to Embodiment 1 of the Present Disclosure] Fig. 1 is a diagram showing a small mobile body according to Embodiment 1 of the present disclosure. In this disclosure, an example in which the small mobile body is a drone is shown, but the present disclosure is not limited to this. In other words, the small mobile body may be a motorcycle, a small passenger car, or a small aerial vehicle including a drone.

[0012] The small vehicle 100 is equipped with a skid 2. The skid 2 is a landing gear, and is a base used when the small vehicle 100 lands.

[0013] A base 4 is installed on the skid 2. Four rotors 6 are connected to the base 4. The rotors 6 are fixed to supports fixed vertically to the base 4 and rotate horizontally relative to the base 4. The rotors 6 are rotated by a motor to levitate the small mobile object 100. This motor emits electromagnetic noise.

[0014] A wireless communication device 8 is mounted on the base 4. A dipole antenna 10 is mounted on the wireless communication device 8.

[0015] The dipole antenna 10 has a support 14 fixed perpendicular to the mounting surface, and two antenna elements 11 fixed to the support 14. The two antenna elements 11 are fixed perpendicular to the support 14 at 180 degrees. To improve radiation efficiency, it is preferable that the two antenna elements 11 have the same length.

[0016] Because the dipole antenna 10 is an ungrounded antenna, it does not require a conductor plate and can perform good wireless communication even in a small installation space where a stable grounding environment cannot be obtained. Therefore, by using the dipole antenna 10, communication quality can be improved even if the wireless communication device 8 is installed near electronic devices such as motors that emit electromagnetic noise.

[0017] 2 is a block diagram showing an example of the configuration of the small moving body according to the first embodiment of the present disclosure, in which the skid 2 and the rotor 6 are omitted.

[0018] The small mobile object 100 includes a base 4. A wireless communication device 8 is fixed onto the base 4 using a holder 5. The wireless communication device 8 is connected to a balun 12 via a coaxial cable 7. The balun 12 is an element that converts between a balanced circuit and an unbalanced circuit. The balun 12 is connected to a dipole antenna 10 via a cable 9.

[0019] A support 14 is fixed onto the base 4 using a holder 5. The support 14 is a jig for stabilizing the antenna element by fixing it to the base 4. A balun 12 and a dipole antenna 10 are fixed to the support 14 using the holder 5.

[0020] [Advantages of the Small Mobile Body According to the First Embodiment of the Present Disclosure] Advantages of the small mobile body according to the first embodiment of the present disclosure will be explained by showing a small mobile body according to a comparative example. Figure 3 is a diagram showing an example of use of a monopole antenna. Here, an example of use is shown in which the monopole antenna 20 is mounted on a small passenger car.

[0021] Monopole antennas operate by grounding one end of the antenna, making them smaller than other antennas. For this reason, monopole antennas are often used when installing wireless communication devices in small mobile devices with limited installation space.

[0022] 4 is a diagram showing a small mobile object according to a first comparative example. The small mobile object 500 differs from the small mobile object 100 in that it has a monopole antenna 20 instead of the dipole antenna 10.

[0023] 5 is a block diagram showing an example of the configuration of a small moving body according to a first comparative example, in which the skid 2 and the rotor blades 6 are omitted.

[0024] The small mobile object 500 includes a base 4. A wireless communication device 8 is fixed onto the base 4 using a holder 5. An antenna base 16 is also fixed onto the base 4 using the holder 5. The wireless communication device 8 is connected to the antenna base 16 via a coaxial cable 7.

[0025] A monopole antenna 20 is installed on the antenna base 16. The antenna base 16 is a jig for stabilizing the antenna element by fixing it to the pedestal 4, and performs the same function as the support 14.

[0026] 4 and 5, the small mobile object 500 has a small mounting space, and as a result, the monopole antenna 20 is installed near electronic devices such as motors that generate electromagnetic noise.

[0027] 6 is a diagram showing the operation of transmitting and receiving radio waves on a drone using the monopole antenna according to the first comparative example. With reference to FIG. 6, interference experienced by the monopole antenna 20 according to the first comparative example will be described in detail.

[0028] As described above, the monopole antenna 20 mounted on the small mobile object 500 is installed near electronic devices such as motors that emit electromagnetic noise. The monopole antenna 20 is a grounded antenna that utilizes a mirror image as its operating principle. On a drone without a conductor plate, the drone body functions as a mirror image of the monopole antenna body. However, the drone body is small compared to the size of the required conductor plate, and its operation as a mirror image is unstable, resulting in a weak mirror image function. Therefore, this electromagnetic noise interferes with wireless communications of the monopole antenna 20 as a mirror image 30a or 30b of the real image 30 of the monopole antenna 20.

[0029] As a result, there has been a problem that communication quality is easily degraded in wireless communication by the wireless communication device 8 mounted on the small mobile object 500. The present disclosure solves this problem by using a dipole antenna 10.

[0030] 7 is a diagram showing a small mobile object according to a second comparative example. The small mobile object 600 differs from the small mobile object 100 in that it includes a dipole antenna 10a in which two antenna elements are fixed to a support pillar at an angle of 180 degrees in parallel.

[0031] The dipole antenna 10a is a larger antenna than the monopole antenna 20. Therefore, the small mobile body 600 equipped with the dipole antenna 10a has a higher center of gravity than the small mobile body 100, which causes a problem of unstable flight.

[0032] The small mobile body 100 of this embodiment is equipped with a dipole antenna 10 in which two antenna elements are fixed to a support 14 at 180 degrees perpendicular to the support, thereby lowering the center of gravity and solving the problem of unstable flight.

[0033] 8 is a diagram showing a small mobile body according to a third comparative example. The small mobile body 700 differs from the small mobile body 100 in that a dipole antenna 10b, with two antenna elements fixed to a support 14 at an angle of 180 degrees and parallel to the support 14, is installed on the bottom surface of the base 4.

[0034] The height of the dipole antenna 10b is greater than the height of the skid 2. In other words, the dipole antenna 10b installed on the bottom surface of the base 4 cannot be accommodated inside the skid 2. Therefore, in the small mobile object 700, the dipole antenna 10b interferes with the ground when landing, making landing difficult.

[0035] In the small mobile object 100 according to this embodiment, the dipole antenna 10 is mounted on the wireless communication device 8, thereby solving the problem of difficulty in landing.

[0036] 2 Skid 4 Base 6 Rotor 8 Wireless communication device 10 Dipole antenna 10a Dipole antenna 10b Dipole antenna 11 Antenna element 14 Support 100 Small mobile body 500 Small mobile body 600 Small mobile body 700 Small mobile body

Claims

1. A small mobile object equipped with a wireless communication device and a dipole antenna with two antenna elements fixed at 180 degrees.

2. The small mobile object according to claim 1, wherein the dipole antenna has a support fixed perpendicular to the mounting surface, and the two antenna elements are fixed perpendicular to the support so as to form 180 degrees.

3. The small mobile object according to claim 1, wherein the two antenna elements have the same length.

4. The small mobile object according to claim 1, wherein the dipole antenna is mounted on the wireless communication device.

5. The small mobile object according to claim 1, which is an aircraft.

6. The small mobile object according to claim 5, further comprising: a skid; a base placed on said skid; and a plurality of rotors connected to said base and rotating horizontally relative to said base, wherein said wireless communication device and said dipole antenna are fixed on said base.

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