JPH0233381Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a helical antenna suitable for use in small communication devices such as portable transceivers.

[Technical background of the invention and its problems]

Conventional helical antennas of this type include those in which a soft insulating material such as a rubber tube is fitted to the outer peripheral surface and tip of a spiral conductor formed in the shape of a relatively small diameter point, or a linear conductor made of glass fiber rod, etc. A conductor is tightly wound into a coil and then coated with vinyl or the like.

However, in the former case, since the bending stress is small, when the spiral conductor as an antenna element comes into contact with surrounding objects during portable use, there is a problem in that large horizontal vibrations occur, which adversely affects communication conditions. In addition, in the latter case, since the glass fiber rod has high rigidity, there is less lateral movement like in the former case, but on the other hand, it remains in a deformed state when it comes into contact with surrounding objects, and has a disadvantage that it has poor restorability. It was hot.

[Purpose of invention]

The purpose of the present invention is to provide a helical antenna with a simple structure that exhibits little lateral vibration even when it comes into contact with surrounding objects, allows good communication, etc., and is highly elastic and has excellent restorability.

[Summary of the idea]

In order to achieve the above object, the present invention is characterized by the following structure. That is, an insulating elastic reinforcing rod having an outer diameter smaller than the inner diameter of the helical conductor is inserted into the inside of the helical conductor serving as the antenna element, and the outer peripheral surface of the insulating elastic reinforcing rod and the inner surface of the helical conductor are connected. In order to create a uniform gap between the insulating elastic reinforcing rod and the helical conductor, a first
and a second combined body is fitted into the joint.

[Example of idea]

The figure is a front view showing an embodiment of the present invention with the right half cut away. In the figure, 1 is a spiral conductor as an antenna element. For example, when the spiral conductor 1 is used as a helical antenna for amateur radio in the 144 MHz band or 430 MHz band, a relatively thin conducting wire (for example, 1 mm in diameter) is wound as shown in the figure. 2 is the above spiral conductor 1
It is an insulating elastic reinforced rod made of reinforced plastic (commonly known as FRP: Fiber reinforced plastics) having an outer diameter smaller than the inner diameter of the conductor 1, and is inserted into the center of the spiral conductor 1. The insulating elastic reinforcing rod 2 used has a required bending strength depending on the intended use of the antenna. Reference numeral 3 denotes a soft insulating material tube made of rubber, vinyl, etc., fitted around the outer periphery of the spiral conductor 1. Reference numeral 4 denotes a bottomed cylindrical protective cap as a first assembly, and a fitting hole 41 into which the tip of the insulating elastic reinforcing rod 2 fits is provided at the center of its inner bottom. Further, the inner circumferential wall of the protective cap 4 is provided with a holding portion 42 for holding the outer circumferential surface of the distal end portion of the spiral conductor 1 and a fitting portion 43 that engages with the distal end portion of the soft insulating tube 3. Reference numeral 5 designates a mounting element as a second coupling body, which is made of a conductor such as brass and has a jack portion 5A for connecting a coaxial cable at the lower end of the base, and a coupling protrusion 5B at the upper end. There is. The coaxial cable connecting jack portion 5A is fitted into a plug portion attached to a transceiver case (not shown) to achieve electrical and mechanical connection. The coupling protrusion 5B has a substantially cylindrical shape, and a fitting hole 51 is provided in the center thereof, into which the base end of the insulating elastic reinforcing rod 2 is fitted. Further, the outer peripheral wall of the coupling protrusion 5B is provided with a press-fitting part 52 that is press-fitted into the proximal end of the spiral conductor 1, and a fitting part 53 that is fitted into the proximal end of the soft insulating tube 3. An annular groove 54 is provided at the base of the fitting portion 53 to fit into the base end of the soft insulating tube 3.

Thus the protective cap 4 as the first combination
The spiral conductor 1, the insulating elastic reinforcing rod 2, and the soft insulating material tube 3 are fitted with a mounting element 5 as a second combination body to the distal and proximal ends as shown in the figure. The conductor 1 and the insulating elastic reinforcing rod 2 are held with a uniform gap G interposed therebetween.

In this device configured as described above, the insulating elastic reinforcing rod 2 is disposed at the center of the spiral conductor 1, so compared to the conventional device which does not include the insulating elastic reinforcing rod 2. When using a mobile phone, even if the antenna comes into contact with surrounding objects, the antenna can be prevented from shaking to a minimum. Therefore, the directivity of the antenna is difficult to change, which has the effect of achieving good communication. In addition, compared to a glass fiber rod in which a linear conductor is closely wound, the insulating elastic reinforcement rod 2 is arranged with a uniform gap from the inner circumferential surface of the spiral conductor 1. This ensures good elasticity and provides excellent restorability.

Note that the present invention is not limited to the above embodiment. For example, in the above embodiment, an example was shown in which the antenna was used in a small communication device, but the same effect can be obtained even if it is used in an automobile antenna, for example.

[Effect of idea]

According to the present invention, an insulating elastic reinforcing rod having an outer diameter smaller than the inner diameter of the helical conductor is inserted into the inside of a helical conductor serving as an antenna element, and the outer peripheral surface of the insulating elastic reinforcing rod and the spiral The first and second coupling bodies are fitted to the distal and proximal ends of the insulating elastic reinforcing rod and the helical conductor, respectively, such that a uniform gap exists between the inner circumferential surface of the conductor and the insulating elastic reinforcing rod. Therefore, it is possible to provide a helical antenna with a simple structure that has little lateral vibration even when it comes into contact with surrounding objects, allows good communication, etc., and is rich in elasticity and has excellent restorability.

[Brief explanation of drawings]

The figure is a front view showing an embodiment of the present invention with the right half cut away. DESCRIPTION OF SYMBOLS 1... Spiral conductor (antenna element), 2... Insulating elastic reinforcement rod, 3... Soft insulating material tube, 4... Protective cap (first combination body), 5...
...Mounting element (second combination).

Claims (1)

[Scope of utility model registration request] a spiral conductor as an antenna element; an insulating elastically reinforced rod having an outer diameter smaller than the inner diameter of the spiral conductor and inserted into the spiral conductor; an outer circumferential surface of the insulating elastically reinforcing rod; The insulating elastic reinforcing rod and the first and second coupling bodies fitted to the tip and base ends of the spiral conductor, respectively, so that a uniform gap exists between the inner circumferential surface of the spiral conductor. A helcal antenna characterized by the following.