JPH042488Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a shortened antenna suitable for mobile radio communication devices, particularly hand-held transceivers.

[Conventional technology and problems]

Wireless communication requires an antenna to radiate or sense radio waves for both transmission and reception.
Long antennas such as long antennas, inverted L-shaped, and slanted antennas are often used, and antennas based on 1/2 wavelength doublet antennas are often used in the shortwave (SW) and very high frequency (VHF/UHF) bands. This is as shown in Figure 5A.
Straight conductor (element) with a length of approximately 1/2 the wavelength
Since the transmitter output is current fed to the center of the element, the current is 0 at both ends of the element and no power is reflected, so the antenna is matched to the transmitter and loss is minimized. This applies not only to transmission but also to reception. In addition, what is called a Yagi antenna is one in which a waveguide element and a reflection element are added.Since it has a directional rotation structure to utilize directivity, in the frequency band where the element is long, a loading coil is placed in the middle of the element. A technique is applied to shorten the length of the element by inserting .

However, in a portable communication device (commonly known as a transceiver), it is difficult to use the doublet antenna that feeds electricity at the center of the element due to its shape, so a ground element is added to only half of the doublet element as shown in Figure 5B. Furthermore, if this element is installed directly on the transceiver, the transceiver itself acts as a ground, so the ground element is unnecessary, and the fifth
Since it has a simple shape as shown in Figure C and is convenient to carry, it is called a rod antenna and is used in the vast majority of cases.

An antenna with the above shape basically operates with a length of 1/4 wavelength, so in the case of amateur radio, the element length is approximately 1/4 wavelength in the 50MHz (6m) band.
1.5m, approximately 50cm in the 143MHz (2m) band, 460MHz
(0.65m) band is approximately 16cm. Therefore, in the 50 MHz and 143 MHz bands, the concentric pipe is shaped like a concentric pipe as shown in Figure 6A to make it convenient to carry, and a spherical or disc shaped tip is used to shorten the overall length and increase radiation efficiency. For a long time, antennas with added top loading such as cylindrical, radial, etc., and shortened antennas with a loading coil added to the base of the antenna element to shorten the overall length, as shown in Figure 6B, have been used for a long time. Recently, however, as transceiver bodies have become smaller and lighter, there has been a desire for even smaller antennas, and a shortened antenna (see Figure 6C) in which the entire antenna element is wound into a solenoid coil shape has been developed. In this situation, coil antennas (hereinafter referred to as coil antennas) have become mainstream for use in handy type transceivers.

In terms of production, for a basic antenna like the one shown in Figure 5A, once the design dimensions are corrected by actual measurements, a homogeneous product can be obtained by simply maintaining dimensional accuracy, but with shortened antennas, the greater the shortening ratio, the more In general, adjustment is delicate, and even if the number of turns of the same wire is the same in a coil antenna, it is affected by slight differences in the pitch of the windings, so in the production process, the total number of turns should be increased by 1 to 2 turns over the specified value. The tip of the winding is cut off after it is installed in the transceiver until the transmitting SWR is optimized, but cutting off too much will result in a defective product, so it is a process that requires extreme skill to quickly adjust to the optimum condition. Furthermore, in order to protect the coil element from dirt and deformation, a protective cover made of artificial rubber, silicone rubber, or polyethylene is used with the lid covered, so it is necessary to adjust the coil element to account for a decrease in the tuning frequency due to an increase in the distributed capacitance of the coil. However, there was a problem in that it was extremely difficult to arrange all the products in an optimal state.

[Purpose of invention]

In this invention, instead of using the primitive cut-and-try method in the adjustment process of a shortened coil antenna as seen in the prior art, the final form allows the protective cover to be overturned, making it possible to easily adjust the optimum state. The purpose of the present invention is to provide a structure of a coil-type shortened antenna.

[Summary of the idea]

This invention is described in claim 1 of the utility model registration and as shown in FIG. 1, is a shortened antenna in which the radiating element is formed in the shape of a solenoid coil, and the antenna is adapted to the inner shape of the coiled element 1. This shortened antenna is characterized in that a metal conductor type core 2 provided with a spiral groove is inserted in an adjustable manner.

A basic tuned antenna is a distributed constant type whose element length is closely related to the radio wavelength, but a shortened antenna has its overall length shortened by replacing part or all of it with a lumped constant loading coil. In particular, a shortened antenna formed entirely in the shape of a solenoid coil can be finished to the desired overall length by adjusting the diameter and winding pitch of the coiled element 1, making it highly effective as a shortened antenna. The problem mentioned in the prior art section occurred during the adjustment process. However, in the shortened antenna of the present invention, the number of turns of the coiled element 1 is increased by several times to make the resonance frequency of the element slightly lower than the desired value, and the metal conductor type core 2 is screwed into the coil 1. By short-circuiting the windings, the inductance is reduced and the resonant frequency is increased to the desired frequency, making it easy to adjust to the optimum state while checking the scale of the transmitter's SWR meter. At this time, if the inner diameter of the coil 1 forms a threaded hole in the helical groove 21 of the core 2, and if the pitch of the groove 21 and the winding pitch of the coil are slightly different, then the core 2 will be the same as the coil 1. to ensure contact with the windings to shorten and hold them. Practical materials for the core 2 include copper, brass, and aluminum, and a groove 22 for an adjustment driver is provided at one end to enable continuous adjustment.

Since a coil antenna is used by directly attaching it to a portable transceiver and can be removed and stored when not needed, in claim 2 of the utility model registration, a coiled element 1 is used as shown in FIG.
A metal conductor type core 2 provided with a helical groove that matches the inner shape of the coiled element 1 is adjustable therein, and a detachable connector 3 is attached to one end 11 of the coiled element 1.
This article describes a shortened antenna as set forth in claim 1 of the utility model registration claim, which is characterized in that it is equipped with a.

In addition, since the coiled element has an air-core structure, it is easily deformed if left as is, and in order to prevent an increase in high frequency loss due to rust on the conductor surface,
In claim 3 of the utility model registration, as shown in FIG. This article describes the structure of a shortened antenna according to claim 1, which is characterized in that a shaped element 1 is covered with a protective insulator 4.

As a practical structure of the coil antenna of the present invention when applied to a portable transceiver, as shown in claim 4 of the utility model registration and FIG.
A metal conductor core 2 provided with a helical groove that matches the internal shape of the coiled element 1 is adjustable therein, and one end 1 of the coiled element 1 is inserted into the coiled element 1.
A shortened antenna according to claims 1, 2 and 3 of the utility model registration claim, characterized in that a detachable connector 3 is attached to the coiled element 1 and the coiled element 1 is covered with a protective insulator 4. List.

In this case, the proximal end 1 of the coiled element 1
1 has a structure in which it is tightly supported by the center conductor 31 of the connector 3, so that the adjustment core 2 is inserted into the coiled element 1 from the tip 12 side. At that time, the core 2 itself and the coil portion shortened by the core 2 serve as top loading for the coiled element 1.
Compared to conventional simple coiled elements, advantageous results are obtained in terms of shortening effect and radiation efficiency.

[Effect of idea]

Coil antennas are used as an extremely convenient antenna form in portable transceivers, which require small size and light weight, but as mentioned in the prior art section, there was a problem with the difficulty of adjustment. By applying this invention, adjustment does not require mechanical processing such as cutting off the coiled element itself, and the metal conductor can be adjusted while observing the pointer of the transmitter's SWR meter in its final form, which is also coated with a protective insulator. By simply turning the manufactured core, you can easily adjust to the best SWR point, greatly improving production efficiency.
Moreover, it has great practical value, as it allows fine adjustment and confirmation of the adjustment state during use, if necessary.

[Brief explanation of the drawing]

Figure 1 is a structural diagram of the coil antenna of the present invention, Figure 2 is a second structural diagram of the coil antenna of the present invention,
Fig. 3 is a third structural diagram of the coil antenna of the present invention, Fig. 4 is a fourth structural diagram of the coil antenna of the present invention, and Figs. 5 and 6 are examples of shapes of various antennas according to the prior art. . 1... Coiled antenna element, 2... Metal conductor core, 3... Attachment/detachment connector, 4... Protective insulator.

Claims (1)

[Claims for Utility Model Registration] (1) In a shortened antenna in which the radiating element is formed in the shape of a solenoid coil, the metal conductor core in which the coiled element is provided with a helical groove that conforms to the inner shape of the coiled element can be adjusted. A shortened antenna characterized by having a (2) A metal conductor core provided with a helical groove that matches the internal shape of the coiled element is inserted into the coiled element in an adjustable manner, and a detachable connector is attached to one end of the coiled element. , a shortened antenna according to claim 1 of the utility model registration claim. (3) A metal conductor core provided with a helical groove that matches the internal shape of the coiled element is adjustable and inserted into the coiled element, and the coiled element is coated with a protective insulating material. A shortened antenna according to claim 1 of the utility model registration claim. (4) Adjustably inserting a metal conductor core provided with a helical groove that matches the internal shape of the coiled element into the coiled element, attaching a detachable connector to one end of the coiled element, and attaching a detachable connector to one end of the coiled element; The shortened antenna according to claim 1, which is coated with a protective insulator.