JP2000174525A - High frequency antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain stable reception by eliminating a strong disturbing radio wave without revamping a printed circuit board of a radio receiver. SOLUTION: A band pass filter 12 is fitted to a high frequency antenna for replacement purpose. On the occurrence of deteriorated sensitivity or crosstalk or the like resulting from reception of a strong disturbing radio wave, the high frequency antenna is replaced with the high frequency antenna to which the band pass filter 12 is integrated to eliminate the strong disturbing radio wave and to attain stable reception of an objective radio wave. When no disturbing radio wave is in existence, the high frequency antenna without the filter 12 is used to attain reception with high sensitivity. Since it is not required to revamp a filter that is precisely adjusted on a printed circuit board, the disturbing radio wave can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency antenna, and more particularly, to a high-frequency antenna for a small-sized mobile radio communication terminal for removing jamming waves.

[0002]

2. Description of the Related Art A small mobile radio communication terminal such as a portable telephone cannot use a full-size high-performance antenna such as a fixed radio station, and must use a small antenna with poor frequency characteristics. . A conventional high-frequency antenna has a structure as shown in FIG. In FIG. 6, a receiver 51 is a wireless receiver main unit, a booster, or the like. The matching circuit unit 52 is a circuit for matching impedance between the receiving electronic circuit and the antenna element. Element 53 is an antenna element for receiving a radio wave. The cover 54 is a cover that covers the entire antenna. FIG. 7 is a diagram illustrating reception characteristics of a conventional antenna. It has a wideband characteristic of receiving radio waves other than the target frequency band centered on the frequency f ₀ at substantially the same level as the target frequency band.

In a conventional receiver, a matching circuit 52
The interference band outside the reception band is limited by the matching adjustment of the antenna and the adjustment of the antenna element 53, and the reception band of the high-frequency antenna is adjusted to receive only the target radio wave. In addition, a precisely adjusted filter is provided on a printed circuit board inside the housing to limit an interference wave outside the reception band.

[0004]

However, in the above-mentioned conventional high-frequency antenna, strong interfering radio waves outside the reception band cannot be removed, and if the filter mounted on the printed circuit board is not sufficient, the sensitivity is suppressed. -Had problems such as interference. Also, if the filter mounted on the printed circuit board is designed to remove strong jamming waves outside the reception band, the sensitivity when the jamming waves are not strong will be reduced, making normal use difficult. There was a problem. If the filter mounted on the printed circuit board is switched only when the interference is strong, there is a problem that the circuit becomes complicated and the cost increases.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a high-frequency antenna capable of removing strong interfering radio waves and enabling stable reception.

[0006]

In order to solve the above-mentioned problems, according to the present invention, a high-frequency antenna includes an antenna element for receiving a radio wave, and a band-pass filter for removing a radio wave outside a reception band received by the antenna element. And a filter. With this configuration,
Stable reception is possible by removing strong jamming radio waves.

[0007] Further, a connector for detachment is provided on the high-frequency antenna. With this configuration, high-sensitivity reception can be performed using the same high-frequency antenna as in the past when used in an environment without interference, and a filter is incorporated when used in an environment with strong interference. By replacing it with a high-frequency antenna, it is possible to remove strong interfering radio waves and achieve stable reception.

Further, the band-pass filter is a SAW filter, a dielectric filter or a quartz filter. With this configuration, stable reception can be performed at a low cost by removing strong interference radio waves.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention comprises an antenna element for receiving a radio wave, and a band-pass filter for removing a radio wave outside a reception band received by the antenna element. It is a high-frequency antenna, and has an effect of removing radio waves of unnecessary frequencies outside the band by a band-pass filter.

The second aspect of the present invention is the first aspect.
The high-frequency antenna described above is provided with a detachable connector, and has an effect of making the antenna replaceable.

According to a third aspect of the present invention, in the high frequency antenna according to the first or second aspect, the filter is a SAW filter, and has an effect of removing a strong interfering radio wave by the SAW filter.

According to a fourth aspect of the present invention, in the high-frequency antenna according to the first or second aspect, the filter is a dielectric filter, and has an effect of removing strong interfering radio waves by the dielectric filter. Have.

According to a fifth aspect of the present invention, in the high-frequency antenna according to the first or second aspect, the filter is a quartz filter, which has an effect of removing strong interfering radio waves by the quartz filter.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described in detail with reference to FIG.

(Embodiment) An embodiment of the present invention is a high-frequency antenna in which a band-pass SAW filter or the like for removing unnecessary interference is incorporated inside a replaceable antenna.

FIG. 1 is a diagram showing a configuration of a high-frequency antenna according to an embodiment of the present invention. In FIG. 1, the receiver 11
Is a receiver body or a booster for receiving. The filter unit 12 is a band-pass filter that attenuates radio waves other than the reception band. The element 13 is an element of a whip antenna for receiving a radio wave.
The cover 14 is a cover that covers the entire antenna.

FIG. 2 is a diagram showing a circuit configuration of the band-pass filter. FIG. 3 shows the input / output characteristics. In FIG. 2, an input matching unit 21 is a circuit for matching impedance between the element 13 and the filter main body 22. The filter body 22 is a filter element such as a SAW filter, a dielectric filter, and a quartz filter. The output matching unit 23 is a circuit for matching the impedance between the filter body 22 and the receiving circuit. It should be noted that the input / output matching unit 23 can be omitted when impedance matching is achieved, or can be omitted when impedance mismatching does not significantly affect performance.

The operation of the high-frequency antenna configured as described above according to the embodiment of the present invention will be described with reference to FIGS. The incoming target radio wave is
, Passes through the filter unit 12 with almost no attenuation, reaches the receiver 11, and is received. Further, undesired jamming radio waves having an out-of-band frequency are received by the element 13, but are strongly attenuated by the filter 12, and hardly reach the receiver 11.

FIG. 4 shows the band characteristics of the high-frequency antenna according to the embodiment of the present invention. It can be seen that the bandgap characteristics are narrower than those of the conventional high frequency antenna shown in FIG.

FIG. 5 is a diagram comparing the band characteristics of a receiver having a high-frequency antenna with a built-in filter according to the embodiment of the present invention with the band characteristics of a receiver having a conventional high-frequency antenna. FIG. 5A shows a band characteristic of a receiver having a conventional high-frequency antenna.
(B) shows the band characteristic of the receiver having the high-frequency antenna with a built-in filter according to the embodiment of the present invention.

As is clear from FIGS. 4 and 5, the high-frequency antenna according to the embodiment of the present invention can almost completely remove out-of-band radio waves by using the high-frequency antenna alone. In the case of strong jamming radio waves, they slightly pass through the filter section 12, but are removed by a band-pass filter built into the receiver main body 11, and almost no jamming occurs. In the case where there is no jamming radio wave, if an antenna without a filter is used, radio waves in a target band are not attenuated by the filter, so that high-sensitivity reception is possible.

In the above description, the example in which the filter is provided in the whip antenna has been described. However, the present invention can be similarly applied to other antennas. Further, the present invention can be similarly implemented by using a filter other than the SAW filter, the dielectric filter, and the quartz filter.

As described above, in the embodiment of the present invention,
Since the high-frequency antenna has a built-in replaceable band-pass filter that removes unwanted interference, replace the antenna when the interference is strong and remove the interference of out-of-band frequencies. Can be.

[0024]

As described above, according to the present invention, a high-frequency antenna is provided with an antenna element for receiving radio waves,
Since it has a configuration with a band-pass filter that removes radio waves outside the reception band received by the antenna element, unnecessary frequencies outside the band are removed by the antenna alone, and stable reception without sensitivity suppression or interference is achieved. The effect that it can be obtained is obtained.

Further, since the high-frequency antenna is provided with a detachable connector, when there is an interfering radio wave, by replacing the radio-frequency antenna with a high-frequency antenna having a band-pass filter, stable reception without sensitivity suppression, interference, or the like can be obtained. The effect that it can be obtained is obtained.

Since the band pass filter is a SAW filter, a dielectric filter or a quartz filter,
The effect that a small and low-cost antenna with a built-in filter can be realized is obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a high-frequency antenna according to an embodiment of the present invention;

FIG. 2 is a functional block diagram of a band-pass filter used for a high-frequency antenna according to the embodiment of the present invention;

FIG. 3 is an input / output characteristic diagram of a band-pass filter used for a high-frequency antenna according to an embodiment of the present invention;

FIG. 4 is a band characteristic diagram of the high-frequency antenna according to the embodiment of the present invention;

FIG. 5 is a diagram comparing the band characteristics of a receiver with a high-frequency antenna according to the embodiment of the present invention with the band characteristics of a receiver with a conventional high-frequency antenna;

FIG. 6 is a configuration diagram of a conventional high-frequency antenna,

FIG. 7 is a band characteristic diagram of a conventional high-frequency antenna.

[Explanation of symbols]

 11 Receiver 12 Filter section 13 Element section 14 Antenna cover 21 Input matching section 23 Output matching section 22 Filter body 51 Receiver body or booster 52 Matching circuit section 53 Element section 54 Antenna cover

Continued on the front page F term (reference) 5J046 AA02 AA09 AB06 AB12 BA01 5J047 AA02 AA09 AA19 AB06 AB12 FD01 5K062 AB02 AB07 BC03 BF05

Claims (5)

[Claims] 1. A high-frequency antenna comprising: an antenna element for receiving a radio wave; and a band-pass filter for removing a radio wave outside a reception band received by the antenna element. 2. The high-frequency antenna according to claim 1, further comprising a detachable connector. 3. The high frequency antenna according to claim 1, wherein said band pass filter is a SAW filter. 4. The high-frequency antenna according to claim 1, wherein said band-pass filter is a dielectric filter. 5. The high frequency antenna according to claim 1, wherein said band pass filter is a quartz filter.