JPS6362402A - Antenna for radio equipment - Google Patents

Abstract

PURPOSE:To attain the changeover of the resonance frequency electrically simply by connecting a switching diode in parallel with a prescribed interval in parallel with a short-circuit pin between a radio equipment case and a plate shape radiation element. CONSTITUTION:The plate shape radiation element 2 is arranged in parallel with a face such as a side face or an upper face of the metal-made radio equip ment case 1. One end of the plate shape radiation element 2 is connected to the radio equipment case 1 by using the short-circuit pin 3 and the radio equip ment case 1 and the plate radiation element 2 are energized by a feeder 4. A switching diode 5 switching the resonance frequency while causing the short- circuit in terms of high frequencies by impressing a bias voltage between the radio equipment case 1 and the plate element 2 is connected in parallel with the short-circuit pin 3 at a prescribed interval. A bias voltage is impressed to the switching diode 5 to switch the resonance frequency.

Description

[Detailed Description of the Invention] [Summary] In an inverted F-type radio antenna, a switching diode is used to short-circuit between a metal radio casing and a plate-shaped radiating element, and the short-circuit position is switched. In addition, the resonant frequency is switched by isometrically changing the width of the short circuit.

[Industrial application field]

The present invention relates to a miniaturized inverted-F type radio antenna for portable radio telephones and the like.

In radio devices such as portable radio telephones, an inverted F-type antenna in which a plate-shaped radiating element is arranged parallel to the surface of a metal casing is relatively often used. It is desired that such an inverted F-type antenna can be used in various frequency bands by switching the resonant frequency.

, [Prior Art] For example, a radio device has a configuration shown in FIG.
The audio signal from 6 is sent to a low frequency processing section 17 .

and is amplified by the transmitter 18 at a transmission frequency of, for example, 800.
The signal is modulated to MHz and applied to a power amplifier 19, and amplified by the power amplifier 19. The signal is applied to the antenna 11 via the duplexer 12 and transmitted. Also antenna 11
The signal received by
and is amplified and applied to the receiver 15.

An inverted F-type antenna is used as the antenna 11 of such a radio device. Since the inverted F-type antenna can receive horizontal and vertical polarization components, it is suitable as a radio antenna for use in urban areas where the plane of polarization rotates. In this inverted F-type antenna, when the corner of the plate-shaped radiating element is short-circuited to the metal radio casing, the length of the periphery of the plate-shaped radiating element is approximately 1/2 wavelength. . Also, if one side of the plate-shaped radiating element is short-circuited to the radio device housing,
The length from the short circuit part to the open end is approximately 1/4 wavelength. That is, the resonance frequency is determined by the shape of the plate-shaped radiating element, the position of the short circuit, and the like.

In order to change the resonant frequency of such an inverted F-type antenna, a configuration shown in FIG. 6 was previously proposed.

In the figure, 21 is a metal radio housing, 22 is a plate-shaped radiating element, 23 is a shorting pin, 24 is a power supply line, and 25 is a protrusion. One end of the plate-shaped radiating element 22 is connected and fixed to the wireless device housing 21 by a shorting pin 23, and if the outer four coaxial cables are connected to the non-FA device housing 21, the inner conductor becomes the feeder line 24. The shorting pin 23 is connected to a power feeding point of the plate-shaped radiating element 22 at a predetermined position, and power is supplied between the radio device housing 21 and the plate-shaped radiating element 22 .

Further, the protruding portion 25 is formed on the radio device housing 21 side or the plate-shaped radiating element 22 side, so that the projecting portion 25 is formed on the radio device housing 21 side or the plate-shaped radiating element 22 side.
This acts to increase the capacitance between the antenna and the inverted F-type antenna, thereby lowering the resonant frequency of the inverted F-type antenna.

For example, as shown in Fig. 7, the slot length l is 60 mm.
, the slot width W is 17 mm, and the slot spacing d is 5 m.
m, the height h of the plate-shaped radiating element is 19 mm, the width S of the protrusion is 8 mm, and when the height t of the protrusion is varied in the range of 0 to 5 mm, the resonant frequency CM) Iz shown in Fig. 8 is ) characteristics and specific band c%] characteristics were obtained. That is, the height t of the protrusion
(mm) is gradually increased, and as the interval between the plate-shaped radiating element and the radio device casing is narrowed, the area of wXs in the opposing area between the plate-shaped radiating element and the radio device casing is The resonant frequency decreases because the capacitance between them increases. Therefore, if the resonant frequency is 1200MHz when the height t of the protrusion is O, then the height t of the protrusion is 0 to 5.
By adjusting in the range of mm, the resonant frequency of the inverted F-type antenna can be changed in the range of 1200 MHz to 700 MHz.

In this way, by adjusting the height of the protrusion while keeping the shape of the plate-shaped radiating element constant, it is possible to adjust the resonance frequency or switch the usage band.

[Problem that the invention seeks to solve]

As mentioned above, it is possible to switch the resonant frequency of the inverted F-type antenna, but since the height of the protrusion 25 is mechanically adjusted, it is almost impossible to switch the resonant frequency during use as a radio. It is possible.

An object of the present invention is to enable electrically simple switching of the resonant frequency.

[Means for solving problems]

The radio antenna of the present invention will be described with reference to FIG. One end of the element 2 is connected and fixed to the radio device casing 1 with a shorting pin 3, and power is supplied between the radio device casing 1 and the plate-shaped radiating element 2 through the feeder line 4, and the connection between the radio device casing 1 and the plate-shaped radiating element 2 is Between the
A switching diode 5 that short-circuits at high frequency by applying a bias voltage to switch the resonance frequency.
are connected parallel to the shorting pin 3 at predetermined intervals.

[Effect]

When a bias voltage is applied to the switching diode 5, the switching diode 5 becomes conductive at high frequencies, so that the radio device housing 1 and the plate-shaped radiating element 2 can be short-circuited at a position other than the shorting pin 3. Therefore, since the short-circuit shape between the radio device housing 1 and the plate-shaped radiating element 2 is changed, the resonant frequency can be changed.

〔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, and a metal radio housing 1 houses the components shown in FIG. 5 except for the antenna 11. The plate-shaped radiating element 2 constituting the antenna 11 has one end connected to the radio device housing 1 by a shorting pin 3.
The connection is fixed.

Further, a feeder line 4 is connected at a predetermined interval from the shorting pin 3, and a switching diode 5 is connected to a side different from the side of the plate-shaped radiating element 2 to which the feeder line 4 is connected, parallel to the shorting pin 3 and at a predetermined interval. It is connected. One end of this switching diode 5 is connected to the plate-shaped radiating element 2, and the other end is
For example, the switching diode 5 is connected to a circuit that selectively applies a bias voltage in the radio device housing 1 via a feedthrough capacitor, and the switching diode 5 is connected to the radio device chassis 1 via the feedthrough capacitor in a high frequency manner.

When a forward bias voltage is applied to the switching diode 5, the switching diode 5 becomes conductive, so that the plate-shaped radiating element 2 is short-circuited to the radio device housing 1 via the switching diode 5. Since short circuits occur at positions other than the short circuit pin 3, the isometric short circuit width is changed. This results in switching of the resonant frequency.

Although the plate-shaped radiating element 2 is shown arranged on the side surface of the radio device housing 1, it can also be arranged on the top surface of the radio device case 1.

FIG. 2 shows a bias voltage application circuit according to an embodiment of the present invention, where 2 is a plate-shaped radiating element, 3 is a shorting pin, 5a to 5d are switching diodes, 6a to 6d are feedthrough capacitors, and 7
a to 7b are inductances, 8a to 8d are switches, 9
is the power supply, and ground indicates the radio casing.

When all the switches 8a to 8d are turned off, the switching diodes 5a to 5d are turned off, so that the plate-shaped radiating element 2 is connected to the radio device housing 1 only by the shorting pin 3. In this case, it is also possible to configure so that a reverse bias voltage is applied to the switching diodes 5a to 5d to ensure that the switching diodes 53 to 5d are in the off state.

Further, when all the switches 8a to 8d are turned on, a forward bias voltage is applied from the power supply 9 to the switching diodes 5a to 5d, and the switching diodes 5a to 5d are turned on.
is in the on state. Therefore, the plate-shaped radiating element 2 has switching diodes 5a to 5d at positions other than the shorting pin 3.
It is short-circuited to the radio device housing 1 via the feedthrough capacitors 6a to 6d. Therefore, the resonant frequency will be changed.

When the switching diodes 5a to 5d are connected at predetermined intervals from the shorting pin 3, the switches 8a to 8
By selectively turning on d, the switching diodes 5a to 5d corresponding to the switches 8a to 8d in the on state
is turned on, and the plate-shaped radiating element 2 is turned on at a position other than the shorting pin 3.
and the radio device housing 1 are short-circuited, and the resonant frequency can be changed.

FIG. 3 is a detailed explanatory diagram of the present invention, in which the short-circuit point by the switching diode is shown as a short-circuit stub 6, and the resonance frequency is adjusted by changing the distance F between the short-circuit pin 3 and the short-circuit stub 6. It is something that can be done.

As an example of the dimensions of each part, the horizontal A of the plate-shaped radiating element 2 is 35
mm, length B is 60 mm, thickness C is 1 mm, radio housing 1
The distance between the two surfaces is 12 mm, and the diameter of the shorting pin 3 is 4 mm.
mm, and the distance E between the shorting pin 3 and the feeder line 4 is 14 mm.
In the inverted F type radio antenna, short pin 3
The resonant frequency when the plate-shaped radiating element 2 is short-circuited to the radio housing 1 is 860 MHz, and when the distance F between the short-circuit pin 3 and the short-circuit stub 6 is changed between 0 and 30 mm, the resonant frequency is 860 MHz. In figure.

The tuning curve of the resonant frequency shown was obtained.

In FIG. 4, the solid line curve shows the case where the plate-shaped radiating element 2 is short-circuited to the radio device housing 1 by one short-circuiting stub 6, and as shown in FIG. , 5c, and 5d is equivalent to shorting with only one switching diode in the ON state, and when the distance F is 3Qmm, the resonant frequency is 940MHz, and the resonant frequency is 80
I was able to raise the MHz.

Moreover, the dotted line curve shows the case where short circuit occurs at multiple locations between the short circuit stub 6 and the short circuit pin 3. In this case, it corresponds to the case where multiple switching diodes are turned on and short circuit is performed, and the distance F is 30 mm. The resonance frequency is 960
MHz, and was able to raise the resonant frequency by 100 MHz.

That is, when short-circuiting occurs at a plurality of points between the short-circuit pin 3 and the short-circuit point, the change in the resonant frequency can be made larger than when the short-circuit occurs at only one short-circuit point. In addition,
It is of course possible to change the dimensions of each part, and the resonant frequency will change accordingly, but the resonant frequency can be adjusted by changing the short-circuit point by controlling the on/off of the switching diode.

As mentioned above, the resonant frequency can be adjusted by selectively controlling the switching diode.
Various applications are possible as antennas for radio equipment.

〔Effect of the invention〕

As explained above, the present invention provides a switching method that short-circuits the radio device housing 1 and the plate-shaped radiating element 2 at high frequency by applying a bias voltage in an inverted F-type radio antenna. A diode 5 is connected in parallel with the shorting pin 3 at a predetermined interval, and the switching diode 5
By selecting and applying a bias voltage, it is possible to short-circuit between the plate-shaped radiating element 2 and the radio device housing 1 at a position other than the shorting pin 3, so that the resonance frequency can be switched. Therefore,
It becomes possible to mass-produce radio devices with the same configuration, apply a bias voltage to the selected switching diode 5, and set the resonant frequency corresponding to the band in use.

In addition, in the Breathtalk system where the transmitting frequency and the receiving frequency are different, by selecting the switching diode 5 and applying a bias voltage at the time of transmitting and receiving, the transmitting frequency and the receiving frequency can be changed. can be easily switched.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of an embodiment of the present invention, FIG. 2 is a bias voltage application circuit of an embodiment of the present invention, FIG. 3 is an explanatory diagram of a short circuit point of an embodiment of the present invention, and FIG. 4 is a resonance Frequency adjustment curve diagram, Figure 5 is a diagram of the radio equipment, Figure 6 is a schematic perspective view of the previously proposed antenna, Figure 7 is a perspective view of the antenna part, Figure 8 is the resonance frequency and ratio. It is a band characteristic curve diagram. 1 is a radio device housing, 2 is a plate-shaped radiating element, 3 is a shorting pin, 4
is a power supply line, and 5 is a switching diode.

Claims (1)

[Claims] A plate-shaped radiating element (
2), one end of the plate-shaped radiating element (2) is connected and fixed to the radio device casing (1) with a shorting pin (3), and a power supply line (4) connects the radio device casing (1) and the radio device casing (1). In an inverted F-type radio antenna that feeds power between a plate-shaped radiating element (2), the radio unit casing (1) and the plate-shaped radiating element (2)
) is short-circuited at high frequency by applying a bias voltage to switch the resonant frequency. A switching diode (5) is connected in parallel to the short-circuit pin (3) at a predetermined interval. Antenna for radio equipment.