JPH03220902A - Antenna for portable fm receiver - Google Patents

Abstract

PURPOSE:To allow the antenna to detect an electric field in an excellent way even when the possessor of a receiver carries the antenna or the antenna is placed in a receiver exclusive stand by incorporating the antenna into the stand. CONSTITUTION:A loop antenna 14 taking the effect of a human body into account is employed for a receiver built-in antenna 2, and when the antenna is carried by a person, the body of the person acts like an antenna passing a magnetic field component therein thereby improving the sensitivity. Since the sensitivity characteristic of the loop antenna 14 of the receiver itself cannot be changed, when the antenna is parted from the body of the person, the reception sensitivity is lowered. When the receiver is not carried, for example, it is placed on the table or the like, a receiver 10 is set in an antenna built-in stand 1 and an external antenna 2 is selected. Thus, an electric field is detected from the antenna 2 of the stand 1 and the sensitivity is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an antenna for a portable FM receiver (hereinafter referred to as a receiver).

[Summary of the invention]

The receiver of the present invention consists of an antenna built into the receiver itself and an antenna built into a dedicated stand for the receiver (hereinafter referred to as the stand).When carried, the built-in antenna of the receiver detects radio waves in the air. , relates to an antenna for a portable FM receiver that switches from the receiver built-in antenna to the stand built-in antenna when the stand is set, and the stand built-in antenna detects radio waves in space.

[Conventional technology]

Conventionally, this type of receiver has a built-in antenna because it is a portable receiver, and generally uses a cord of an earphone or the like to double as an antenna.

[Problem to be solved by the invention]

In the conventional receiver described above, there is a strong demand for miniaturization due to emphasis on portability, and the length of the antenna cannot be increased, so reception sensitivity must be maintained in a small space. Therefore, the reception sensitivity of the receiver when it is carried is susceptible to the influence of the human body, often resulting in a decrease in sensitivity. Furthermore, when the receiver is placed on a table or the like, it is susceptible to the effects of antenna directivity and noise, and even in such a case there is a problem of reduced reception sensitivity.

Means for Solving the Problem] In order to solve the above problem, in the present invention, the built-in antenna of the receiver has a built-in loop antenna that takes into account the influence of the human body, and when a person carries it, the magnetic field It becomes a component and becomes an antenna, improving sensitivity.

However, since the sensitivity characteristics of the receiver's loop antenna cannot be changed, the reception sensitivity decreases when it is moved away from the human body. Therefore, when the receiver is not carried, for example, when it is placed on a table, the receiver is set on a stand with a built-in antenna and switched to an external antenna. By doing so, the electric field can be detected from the stand's antenna and the sensitivity can be improved.

[Effect]

According to the above configuration, for example, there is no need to take out an antenna cord from the receiver itself, and even in the case of a cart-type receiver, receiving sensitivity can be ensured by standing it on a stand.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a dedicated receiver stand 1 to which an embodiment of the present invention is applied, in which an antenna 2 is built-in.

The antenna 2 can be made of any material and shape as long as it matches the frequency received by the receiver and has good sensitivity. However, the structure must be such that it functions as an external antenna when the receiver is set up. In the case of the present invention, for example, there is a structure in which a contact point 3 is provided at the bottom of the stand, and the structure is such that it can be switched to an external antenna when a receiver is placed on it.

FIG. 2 is an outline diagram of a portable FM receiver to which an embodiment of the present invention is applied. This receiver 10 is provided with a contact portion 11 for switching to an external antenna when set on a stand.

FIG. 3 is a configuration diagram of a receiver and a stand showing an embodiment of the present invention. The receiver 10 includes a contact section 11, a receiving section 12.
Impedance matching device 13. It is composed of a loop antenna 14. When the receiver is carried, the towing section 11 is connected in the direction a, and the loop antenna functions as a receiver antenna. When the stand is at seven points, contact part 1 of the receiver
1 is connected in the b direction, and the impedance matching device 13 and the antenna 2 built into the stand are connected. By doing so, the loop antenna 14 built into the receiver is opened to the receiving section 12 in the receiver, and the electric field input antenna of the receiving section becomes an external antenna.

This figure illustrates an example of the joining method.
A contact portion 3 of the antenna terminal protrudes upward from the bottom of the stand 1, and when the receiver 1O is set on the stand 1, the contact portion 11 within the receiver functions as a switch and is switched in terms of circuitry. Any structure may be used as long as the antenna can be switched.

FIG. 4 is a circuit diagram showing an embodiment of the present invention.

The configuration in FIG. 3 is shown in a circuit diagram. Contact part 1
1 functions as a switch, and the built-in antenna 2
and the loop antenna 14 of the receiver 10.

Note that the loop antenna 14 includes a coil 14a and a capacitor 1.
4b. Next, the impedance matching device 13 includes a coil 13a and a capacitor 13b for matching with the antenna 2 built into the stand. The connection method is as shown in the figure.

By doing the above, it is possible to switch the antenna.

〔Effect of the invention〕

As explained above, in the present invention, when the receiver is carried, reception can be received using the antenna inside the receiver, and when it is placed on a stand, reception can be received using the antenna built into the stand. Both can detect good electric fields. In addition, receivers have recently become smaller and thinner, making them more portable, and such receivers have particularly poor reception sensitivity when placed somewhere. Therefore, the problem can be solved by placing it on a stand as in the present invention. Furthermore, if a receiver or the like has a display function such as a message, it is possible to easily check the message by placing it on a stand.

[Brief explanation of drawings]

Figure 1 shows a dedicated receiver stand to which the present invention can be applied;
The figure is a portable FM receiver showing an embodiment of the present invention, FIG. 3 is a block diagram of the receiver and stand of the present invention, and FIG. 4 is a circuit diagram showing an embodiment of the present invention. l ・ ・ 2 ・ ・ 3 ・ ・ 10 ・ ・ 11 ・ 12 ・ 13 ・ 13 points ・ 13b ・ 14 ・ 14a ・Stand built-in antenna contact receiver contact part receiving part impedance matching device coil capacitor loop antenna coil 4b More than a capacitor

Claims (2)

[Claims] (1) In the antenna for a portable FM receiver, the portable F is characterized by having the antenna built into a stand dedicated to the receiver.
Antenna for M receiver. (2) An antenna for a portable FM receiver, characterized in that when the portable FM receiver is set on a stand, the antenna inside the receiver is switched to an antenna built into the stand.