JPS6234406A - Antenna for radio equipment - Google Patents

Abstract

PURPOSE:To obtain an antenna which has double hump response or flat wide band response by arranging plate type radiation elements which differ in resonance frequency in parallel to the surface of a metallic radio equipment housing. CONSTITUTION:A coaxial cable 5 is used for feeding between the metallic radio equipment housing 1 and a plate type radiation element 2 right above it; the internal conductor 5a is connected to the plate type radiation element 2 and the external conductor 5b is connected to the radio equipment housing 1. Further, a coaxial cable 6 is used for feeding between the plate type radiation elements 2 and 3; the internal conductor 6a is connected to the plate type radiation element 2 and the external conductor 6b is connected to the plate type radiation element 3. There are various methods for making the plate type radiation elements 2 and 3 different in resonance frequency. For example, projection parts 7 and 8 are formed on radiation tip sides and electrostatic capacity is added between the radio equipment housing 1 and plate type radiation element 2 and the plate type radiation elements 2 and 3.

Description

[Detailed Description of the Invention] [Summary] A plurality of plate-shaped radiating elements each having a different resonant frequency are arranged parallel to the top or side surface of a metal radio casing, and one end of the plate-shaped radiating elements is grounded to the radio casing. However, by feeding power between the radio housing and the radiating element and between the radiating elements, an inverted F antenna having a plurality of resonant frequencies is constructed, and a small, wideband antenna is realized.

[Industrial application field]

TECHNICAL FIELD The present invention relates to a miniaturized antenna for a radio device such as a portable radio telephone.

[Conventional technology]

The radio device has, for example, the configuration shown in FIG.
The signal is modulated to Hz and applied to the power amplifier 19. The signal amplified by the power amplifier 19 is applied to the antenna 11 via the duplexer 12 and transmitted. Also antenna 11
The received signal is applied to the receiving section 13 via the duplexer 12. This receiving section 13 demodulates the signal to become a low frequency signal, which is added to the low frequency processing section 14 where it is amplified and placed on the receiver 1.
Added to 5.

When such a radio device is configured to be portable, a 1/4 wavelength whip antenna is often used as the antenna 11. However, this whip antenna has the disadvantage that it protrudes from the radio casing and obstructs operation.

Therefore, recently, an inverted F antenna using a plate-shaped radiating element has been adopted. This inverted F antenna uses a metal radio casing as a grounding plate, arranges a plate-shaped radiating element parallel to the radio casing, and connects and fixes one end of the plate-shaped radiating element to the radio casing. A power feeding point is provided at a predetermined position between the tip and the grounding part.

Since this inverted F antenna is capable of receiving horizontal and vertical polarization components, it is a suitable radio antenna for use in urban areas where there are many cross-polarized components.

[Problem that the invention seeks to solve]

Portable radio telephones use two frequencies in order to transmit and receive at the same time, similar to ordinary telephones. Therefore,
An antenna for a portable radio telephone is required to have wideband characteristics.

However, the aforementioned inverted F antenna has a single resonant frequency and a relatively narrow band. In this inverted F antenna, it is known that the band is wider when the corner of the plate-shaped radiating element is grounded than when the center of one side of the plate-shaped radiating element is grounded. However, even if such means are adopted, the band will only become slightly wider.

Broadband characteristics can be obtained by increasing the distance between the casing, which serves as a grounding plate, and the plate-shaped radiating element, but in order to achieve a practically sufficient broadband characteristic, the distance must be made very large. (This means that the advantage of the inverted F antenna, which can be made smaller, will be lost.)

The present invention improves the above-mentioned conventional drawbacks, and aims to provide broadband characteristics with a simple configuration.

[Means for solving problems]

The radio antenna of the present invention will be described with reference to FIG. 1. A plurality of plate-shaped radiating elements 2.3 each having a different resonance frequency are arranged parallel to the surface of a metal radio a housing 1, and One end is connected and fixed to the radio housing 1, and power is supplied between the radio housing 1 and the plate-shaped radiating element 2 and between the plate-shaped radiating elements 2 and 3, and the upper plate-shaped radiating element 3
The power feeding point is indicated by numeral 4.

[Effect]

By arranging a plurality of plate-shaped radiating elements 2 and 3 to configure an inverted F antenna with different resonance frequencies, the frequency characteristic becomes a bimodal characteristic, and a wide band characteristic can be achieved. In addition, since power is supplied between the radio housing 1 and the plate-shaped radiating element 2 and between the plate-shaped radiating elements 2 and 3, it is possible to perform desired impedance matching by setting the feeding points, etc. Become.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic perspective view of an embodiment of the present invention, in which a radio device housing 1 is made of metal and has the structure shown in FIG. 5 built therein. A plurality of plate-shaped radiating elements 2.3 are arranged parallel to the upper surface 1a of the radio device casing 1, and one ends of these elements are connected and fixed to the radio device casing 1. The configuration is such that power is fed between the radio device housing 1 and the plate-shaped radiating element 2 directly above it, and also between the plate-shaped radiating elements 2 and 3, where 4 indicates a feeding point.

FIG. 2 is a sectional view of a main part, and the same reference numerals as in FIG. 1 indicate the same parts. A coaxial cable 5 is used to supply power between the metal radio housing l and the plate-shaped radiating element 2 directly above it, and the inner conductor 5a is connected to the plate-shaped radiating element 2, and the outer conductor 5b is connected to the plate-shaped radiating element 2. Connect to the radio housing 1. Also, a plate-shaped radiating element 2,
3, power is supplied using a coaxial cable 6, with an inner conductor 6a connected to the plate-shaped radiating element 2, and an outer conductor 6b connected to the plate-shaped radiating element 3.

It is possible to adopt various means for configuring the plate-shaped radiating elements 2 and 3 to have different resonance frequencies. For example, a protrusion 7.8 is formed on the radiating tip side, and the radio device housing l
A capacitance is added between the plate-shaped radiating element 2 and the plate-shaped radiating element 2.3.

Since this capacitance changes depending on the height of the protrusions 7 and 8, it can be selected so as to provide a desired resonance frequency.

In such a configuration, for example, the length from the ground end is 60 mm, the width is 30 mm, and the distance between the upper surface 1a of the radio device housing 1 and the plate-shaped radiating element 2, and between the plate-shaped radiating elements 2 and 3. By setting the spacing to 5 mm, it was possible to realize an antenna for the 800-900 MHz band.

Further, by adjusting the lengths of the plate-shaped radiating elements 2 and 3 from the ground end connected and fixed to the radio device housing 1, the resonance frequencies can be set respectively.

FIG. 3 is a VSWR characteristic curve diagram, and curve a.

As shown in b, the antenna has a bimodal characteristic that combines the characteristics of two antennas, and is suitable for wireless communication using two frequencies. Also, if different resonance frequencies are brought close to each other,
It is possible to construct an inverted F antenna with flat frequency characteristics over a wide band.

FIG. 14 is a schematic perspective view of another embodiment of the present invention, in which a plurality of plate-shaped radiating elements 2, 3 are arranged parallel to the side surface 1b of the radio device housing 1.
4 indicates the power feeding point. In this embodiment, the influence of the human body on the antenna can be reduced by arranging the handset on the side opposite to the inverted F antenna.

Although the above-mentioned embodiment shows the case where the plate-shaped radiating elements 2 and 3 are provided, it is also possible to provide a larger number of plate-shaped radiating elements, each having a different resonance frequency. Thereby, it is possible to achieve a wider band. Dielectrics can also be placed within each spacing to provide reinforcement.

〔Effect of the invention〕

As explained above, in the present invention, plate-shaped radiating elements having different resonance frequencies are arranged parallel to the surface of a metal radio casing, and the frequency characteristics as an antenna are bimodal or flat broadband. Therefore, it is very effective when applied to portable wireless devices using wireless communication systems with different transmission and reception bands. Further, by feeding power to each of them as shown in FIG. 2, there is an advantage that impedance matching can be easily achieved.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of an embodiment of the present invention, FIG. 2 is a cross-sectional view of essential parts of an embodiment of the present invention, FIG. 3 is an explanatory diagram of VSWR characteristics, and FIG. 4 is another embodiment of the present invention. A schematic perspective view of an example, FIG. 5 is a block diagram of a radio device. 1 is a radio housing, 1a is a top surface, 1b is a side surface, 2.3 is a plate-shaped radiating element, 4 is a feeding point, 5 and 6 are coaxial cables, 5a
, 6a is an inner conductor, 5b and 6b are outer conductors, and 7.8 is a protrusion.

Claims (1)

[Claims] A plurality of plate-shaped radiating elements (2, 3) each having a different resonance frequency are arranged in parallel to the surface of a metal radio housing (1), , 3) one end is connected and fixed to the radio housing (1), and power is supplied between the radio housing (1) and the plate-shaped radiating element and between the plate-shaped radiating elements, respectively. A radio antenna featuring: