JPH0677874A - Selective call radio receiver - Google Patents

Abstract

PURPOSE:To provide a selective call radio receiver in which spurious radio wave radiation is reduced, its operation is stable and which is proper to miniaturization and cost reduction. CONSTITUTION:A printed circuit board 107 with a receiver circuit component 108 mounted thereon is sandwiched between a couple of conductor plates 106, 110 and the conductor plates 106, 110 are tightened by a screw 103 and a nut 104 to form an electromagnetic shield case for the circuit component 108 thereby reducing spurious radio wave radiation from the printed circuit board mounted circuit 108, especially from its local oscillation circuit to an external device. Furthermore, a ground plate for a microstrip antenna 1 is connected to the conductor plate 106 in terms of high frequencies to allow the conductor plate 106 to act like a ground plate of the antenna 1, then the microstrip board is made small thereby increasing a container volume of components to a receiver. Moreover, the antenna directivity pattern is made stable by providing a ground conductor part around the antenna element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio selective calling receiver for receiving a radio selective calling signal from a base station of a radio selective calling system by means of a microstrip antenna, and more particularly to a radio selective calling receiver which has improved performance and emits less unnecessary radio waves. The present invention relates to a radio selective call receiver which is stable in operation and is suitable for downsizing and cost reduction.

[0002]

2. Description of the Related Art A conventional radio selective call receiver of this type is
A radio selective calling signal (electromagnetic wave) from a base station is converted into a reception signal by a half size type microstrip antenna and supplied to a radio frequency circuit (hereinafter, radio circuit). The received signal is converted into an intermediate frequency signal by the double superheterodyne receiver of the radio circuit, and the intermediate frequency signal is further demodulated into a digital signal by the demodulator of the radio circuit. The digital signal is waveform-shaped by the waveform shaping circuit and then supplied to the decoder. When the decoder confirms that the calling signal included in the digital signal matches its own calling number stored in the ROM, the decoder drives the speaker to make a ringing call, and a message signal is added to the digital signal. If included, LCD (Liquid
A message is displayed on the Crystal-al Display. The wireless selective call receiver includes a battery package, and the decoder includes a DC / DC converter that receives power from the battery package. Each circuit described above includes both the battery package and the DC / DC converter. Alternatively, power is supplied from either one.

Here, the microstrip antenna is manufactured by etching and through-hole processing a microstrip substrate having a dielectric substrate and thin conductors arranged on both surfaces of the dielectric substrate. That is, an antenna element is formed by leaving a quadrilateral conductor on one surface of the dielectric substrate, and a ground plane is formed by leaving the conductor on almost the entire other surface, and one side of the quadrilateral of the antenna element and the ground plane are formed. Connecting with a large number of through holes, this one side is used as a short-circuited side of the antenna element. In this antenna, the area of the ground plane is generally made larger than the area of the antenna element to increase the gain in the front direction (antenna element plane direction).

In the radio selective call receiver, most of electric and electronic parts (the microstrip antenna, LC
(Except D and battery package), that is, most of the receiver circuit is mounted on a printed wiring board (hereinafter referred to as a printed board), and the printed circuit board is supported by a frame that determines the outline of the receiver. ing. The frame further supports the antenna with its base plate facing the ground plane of the printed board. The receiver components described above are further covered by a case.

The level of unwanted radio waves emitted from the radio selective calling receiver is generally defined by a standard. For example, the United States FCC standard (Federal Co
m-munications Commission
Rules and Re-guations, Pa
rt 15), a high frequency device (Radio Frequency De) including the radio selective call receiver.
unnecessary radio wave emission level of
At z to 960 MHz and at a distance of 3 m,
It is set to 46 dBμV / m or less. Since the maximum radio wave radiation in the receiver is usually generated by the first local oscillation circuit (hereinafter referred to as the first LO) of the double superheterodyne receiving section, the radio wave radiation from the first LO included in the printed circuit board should be the most noticeable. There is a need to.

[0006] The radio selective calling receiver has the first LO
Only the shield case is covered and the radio wave emission level is 10d.
It is reduced by about B to satisfy the FCC standard and the like.
However, the installation of the shield case not only increases the height of the printed board of the first LO to increase the thickness of the receiver, but also adds soldering work to the printed board of the shield case. This will increase manufacturing costs.

Further, in the radio selective call receiver, between the microstrip antenna and another receiver circuit,
Further, the structure is such that signal interference is likely to occur between the other receiver circuits via the antenna, and not only unstable operation of the receiver is likely to occur, but also adverse effects due to the approach of external circuits, especially the human body, are likely to occur.

Furthermore, the radio selective call receiver is strongly required to reduce the manufacturing cost by reducing the amount of expensive microstrip substrate used while maintaining the high performance of the microstrip antenna, and to be further miniaturized. Is required.

[0009]

Therefore, the first aspect of the present invention
It is an object of the present invention to solve the above-mentioned drawbacks of the radio selective call receiver according to the conventional technique and to provide a radio selective call receiver with less unnecessary radio wave emission.

A second object of the present invention is to provide a radio selective call receiver having a structure suitable for miniaturization while performing stable circuit operation.

A third object of the present invention is to provide a radio selective call receiver having a high performance and low cost microstrip antenna structure.

A fourth object of the present invention is to provide a radio selective call receiver having a high degree of freedom in design.

[0013]

The radio selective calling receiver according to the present invention, like the receiver according to the prior art, has a microstrip antenna, a radio circuit, a waveform shaping circuit, a decoder, a ROM, a speaker, an LCD and a battery package. Is included. The features of this radio selective call receiver are the receiver structure and the improved structure of the antenna.

In the above radio selective calling receiver, most of the electric and electronic parts constituting the receiver circuit are mounted on a printed board, and the printed board mounting circuit is sandwiched between two conductor plates formed by sheet metal or the like. . One outer surface of the conductor plate and the base plate of the microstrip antenna are connected at high frequencies by means of thermocompression bonding or the like. The two conductor plates are fixed by a conductor connecting rod such as a screw at a position surrounding the printed circuit board mounted circuit, and the conductor plate and the connecting rod constitute a shield case of the printed circuit board mounted circuit, and the shield case is the printed circuit board. An electromagnetic shield is provided between the board-mounted circuit and the antenna and external circuit.
Therefore, the radiated radio waves from the first LO mounted on the printed circuit board are confined in the shield case surrounded by the two conductor plates and the connecting rods, and unnecessary radio wave radiation from the radio selective call receiver to the external circuit is reduced. Not only
Since the signal interference via the antenna between the printed circuit boards is eliminated, the circuit operation of this receiver becomes stable.

In order to increase the antenna gain in the front direction of the microstrip antenna, it is necessary to make the area of the ground plane larger than the area of the antenna element. In this radio selective call receiver, one of the conductor plates having a larger area than the ground plate is connected to the ground plate of the antenna in a high frequency manner, and the conductor plate is equivalently operated as the antenna ground plate. Therefore, the area of the expensive microstrip substrate can be saved almost to the area of the antenna element. Also, since the thickness of the conductor plate is considerably thinner than the thickness of the microstrip substrate, if a part of the antenna base plate is replaced with a conductor plate, the thickness of the microstrip substrate can be converted into a component storage part. The downsizing of the machine can be achieved.

Further, when another conductor film (or conductor plate) is provided further outside the antenna element of the microstrip antenna and this conductor film is connected to the antenna ground plane through the through hole, the conductor film becomes the ground potential. . Therefore, as long as the conductor structure constituting the radio selective call receiver such as the screw is surrounded by the conductor film and the through hole, the conductor of the displacement current generated from the antenna element by the conductor film and the through hole. Block access to structures. Therefore, even if the position or size of the conductor structure is changed, the radiation directivity pattern of the antenna is not affected, and the degree of freedom in structural design of the receiver can be increased.

The resonance frequency of the microstrip antenna can be lowered by providing a conductor cut portion in the antenna element near the short-circuited side. Therefore, if the frequencies of the radio selective calling signals are the same, the antenna element area can be reduced and the receiver can be miniaturized.

[0018]

The present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention.

This radio selective calling receiver converts a radio selective calling signal (frequency 930 MHz) from a base station into a reception signal by a half size type microstrip antenna 1 and supplies the reception signal to a radio circuit 2. This received signal is subjected to double superheterodyne reception by the radio circuit 2, converted into a second intermediate frequency signal (frequency 455 kHz), and further demodulated into a digital signal. This digital signal is waveform-shaped by the waveform shaping circuit 3 and then supplied to the decoder 6. The decoder 6 collates the ringing signal included in the digital signal with its own ringing number stored in the ROM 8, and when it confirms that both signals match, it drives the speaker 5 to make a ringing call. If the digital signal includes a message signal, the decoder 6 displays a message corresponding to the message signal on the LCD 4. The battery package 7 supplies power to the wireless circuit 2, the waveform shaping circuit 3, and the decoder 6 among the receiver circuits described above. The decoder 6 has a DC / D
A C converter (not shown) is included, and the decoder 6
The internal circuits, LCD 4, etc. are supplied with power from the DC / DC converter.

Still referring to FIG. 1, the radio circuit 2
An amplifier 21 for amplifying the received signal from the microstrip antenna 1, a bandpass filter 22, and a first frequency converter (hereinafter, first MIX) receiving the output thereof.
23 and. The first MIX 23 receives the amplified reception signal and the first local oscillation signal (frequency 908M) from the first LO 24.
Hz, signal level, about -10 dBm)
It produces an intermediate frequency signal (frequency 22 MHz). The first intermediate frequency signal has its unnecessary signal component removed by the band pass filter 25, is further amplified by the amplifier 26, and is then supplied to the second frequency converter (hereinafter, second MIX) 27. The second MIX 27 outputs a second signal from the amplified first intermediate frequency signal and a second local oscillator (hereinafter, second LO) 28.
Mixing with the local oscillator signal (frequency 21.445 kHz) produces the second intermediate frequency signal. The second intermediate frequency signal is converted into the digital signal by the demodulator 30 after the unnecessary signal component is removed by the low pass filter 29. Although this receiver further includes a power switch and the like, it is not shown because it does not relate to the gist of the present invention.

The above embodiment will be described with reference to FIGS. 2, 3 and 4 in combination with FIG. 2 is a partially cutaway front view of the embodiment of FIG. 1, FIG. 3 is a sectional view taken along line A1-A2 of FIG.
FIG. 4 is a sectional view taken along line B1-B2 of FIG. The wireless circuit 2 and the first LO 24 represent component mounting areas.

This radio selective calling receiver is a part of the receiver circuit, that is, the radio circuit 2, the waveform shaping circuit 3, the speaker 5, and the like.
Electrical / electronic components 108 for the decoder 6 and the ROM 8 are mounted on the printed board 107. Conductor plate 10 such as sheet metal
6 and 110 are arranged on both sides of the printed board 107 and the LCD 4 supported by the printed board 107, and are spot-welded to the inner surface of the conductor plate 110 and metal screws 103a to 103f arranged so as to surround the printed board 107. They are connected and fixed by the nuts 104a to 104f that are formed. Further, the inner surface of the conductor plate 106 and the ground conductor surface of the printed board 107 (opposite to the component 108 mounting surface) are arranged and fixed so as to be connected in terms of direct current and high frequency. Therefore, the conductor plates 106, 1
The ten, the screws 103a to 103f, and the nuts 104a to 104f form a shield case for the printed board 107 and the electric / electronic parts 108 mounted on the printed board 107, and reduce unnecessary radio wave radiation from the first LO 24 and the like to the outside of the receiver. . For example, R5N4-14D having the above structure
Type wireless selective call receiver (announced in December, 1991, made by NEC Corporation) has an unnecessary radio wave emission level of 3 m away from the first LO 24 without installing a shield case.
It could be reduced to 5 μV / m or less. Further, the outer surface of the conductor plate 106 and the base plate (not shown) of the microstrip antenna 1 are thermocompression-bonded with the pressure-bonding tape 105 interposed therebetween and are connected at high frequencies. Therefore, this receiver structure does not cause high-frequency electromagnetic coupling between the antenna 1 and the printed board 107 and the electric / electronic components 108, and may impair the operational stability of the receiver circuit mounted on the printed board 107. Absent. The conductor plates 106 and 110 have a sufficient electromagnetic shielding effect even if they are partially perforated or have a mesh structure. Also, the screw 103
a to 103f and nuts 104a to 104f
Alternatively, another conductor connecting rod that fixes the two conductor plates 106 and 110 at a predetermined interval may be used.

Further, a frame 102 made of plastic mold is provided with the antenna 1, conductor plates 106, 110,
The printed board 107, the LCD 4 and the battery package 7 are surrounded and the outer shape of this receiver is substantially determined. Further, the case 101 includes the frame 102, the conductor plate 106,
It covers receiver components such as 110 and antenna 1. Arranging the decorative plates on the outer surfaces of the conductor plates 106 and 110 and the antenna 1 helps protect the above-mentioned components. The conductor plate 110 and the case 101 (and the decorative plate) are perforated so that the display surface of the LCD 4 can be seen from the outside of the receiver.

1 to 4, the conductor plate 106 is bent in a crank shape (step shape), and the ground plane of the microstrip antenna 1 is crimped to the recessed plane of the bent conductor plate 106. The battery package 7 having a high component height is housed inside the plane of the convex portion of the conductor plate 106 (on the side of the printed board 107). That is, the conductor plate 106
Is much thinner than the thickness of the antenna 1, the conductor plate 1
By bending 06 into a crank shape, antenna 1
The thickness of this receiver increases the component storage capacity.

Here, the microstrip antenna 1
Receives the radio selective call signal from the direction perpendicular to the plane of the antenna element 11, that is, from the front direction of this receiver.
In this antenna 1, a short-circuit device 13 including a large number of through-holes 13 a forms a short-circuit end of the antenna element 1, and a through-hole 12 between the short-circuit device 13 and the open end 11 a of the antenna element 11 is a feeding point of the antenna 1. It has become. Further, the convex plane portion of the conductor plate 106 constitutes an equivalent ground plane of the antenna 1 to increase the antenna ground plane area and improve the antenna gain Ga in the front direction. The through hole 12 and the input end of the wireless circuit 2 mounted on the printed board 107 (the input end of the amplifier 21) are connected by a connection line 109 such as solder.

FIG. 5 is a structural view of one of the antenna assemblies used in the embodiment shown in FIG. (A) Figure is a front view,
The figure (b) has shown the C1-C2 sectional view of the figure (a).

Referring to FIG. 5, the microstrip antenna 1 and the conductor plate 106 form an antenna assembly.
The antenna 1 is formed by removing a part of the copper foil from a Teflon dielectric substrate 15 having copper foils on both sides by etching.
A quadrilateral conductor antenna element 11 is formed on one surface, and a conductor base plate 16 covering substantially the entire area of the antenna 1 is formed on the other surface.
A side conductor plate 14 surrounding the antenna element 11 is further formed on the surface of the dielectric substrate 15 on the antenna element 11 side. A large number of through holes 14a are provided near the end surface of the side conductor plate 14, and the side conductor plate 14 is connected so as to have the same potential as the ground plate 16, that is, the ground potential. On the other hand, a land 18 connected to the through hole 12 and insulated from the ground plate 16 is formed on the surface of the ground plate 16 side, and this land 18 is used as a feeding point 17 of the antenna 1.

Here, the resonance frequency f0 that maximizes the antenna gain Ga of the microstrip antenna 1 is such that the speed of light is C0, the dielectric constant of the dielectric substrate 15 is εr, and the open end 11a of the antenna element 11 and the short circuiter 13 are connected. When the distance is D1, the frequency f0≅C0 / {4D1 (εr) 1/2}, which varies slightly depending on the thickness t of the dielectric substrate 15 and the like. For example, if the frequency f0 is 930 MHz and the dielectric substrate 15 is Teflon having a dielectric constant εr of 2.17 and a thickness t = 1.6 mm, the calculated distance D1 is 54.5 mm.
Is. However, the actually measured distance D1 was 55.3 mm. The distance S between the short circuiter 13 and the through hole 12 determines the antenna impedance of the antenna 1 as viewed from the wireless circuit 2 side, and is selected as a distance matching the input impedance of the wireless circuit 2.

Still referring to FIG. 5, the through hole 1
4a and the side conductor plate 14 form screws 103a to 10
3d is surrounded and these are shielded from the antenna element 11. Therefore, no matter how the dimensions and positions of the screws 103a to 103d are changed within this condition,
The radiation pattern of the microstrip antenna 1 is not changed. That is, the antenna element 11 and the ground plane 1
6, the surface current S41 is flowing, and the screws 103a to 103d, the side conductor plate 14, and the through hole 14 are provided.
When there is no a, the surface current S41 becomes a displacement current S42 at the open end 11a of the antenna element 11, and this displacement current S42 is terminated at the ground plane 16 and returns to the surface current S41. On the other hand, when the side conductor plate 14 and the through hole 14a are not provided and the screws 103a to 103d are near the antenna element 11, a displacement current (not shown) from the open end 11a is generated by the screws 103a to 103d.
also binds to d. That is, since the magnitude of the displacement current S42 changes depending on the dimensions and potentials of the screws 103a to 103f, the radiation directivity pattern of the antenna 1 is changed to the screw 1
Will be affected by 03a to 103d. Therefore, it becomes difficult to predict the radiation directivity characteristic of the antenna 1 at the design stage of the radio selective call receiver. However, in this antenna 1, since the side conductor plate 14 and the through hole 14a are provided in the vicinity of the antenna element 11 and the antenna element 11 and the screws 103a to 103d are electromagnetically shielded, the surface current S41 is It is only divided into a displacement current S43 flowing through the side ground plate 14 and a displacement current S42 directly terminated at the ground plane 16. Since the position and size of the side ground plate 14 are fixed, the displacement current S41 is not affected by the size and potential of the screws 103a to 103d, and the radiation pattern of the antenna 1 affects the screws 103a to 103d. It does not change even if it is done. Further, even if there are other conductor structures that constitute this receiver, the electromagnetic shielding effect as described above is produced as long as these conductor structures are surrounded by the side ground plate 14 and the through hole 14a. That is clear.

Further referring to FIG. 5, the antenna gain Ga in the front direction of the microstrip antenna 1 is shown in FIG.
As described above with reference to FIG. 4, the larger the area of the ground plane 16 is, the larger the area of the antenna element 11 becomes. In this antenna assembly, the conductor plate 106 is connected to the ground plane 16 in a high frequency manner, and the convex plane, which is a plane extending in the same direction as the ground plane 16, is further extended from the short-circuit device 13 by a distance W1. The antenna 1 acts as a ground plane. Therefore, this antenna assembly increases the antenna gain Ga in the front direction as compared with the case of the antenna 1 alone. A specific example of increasing the antenna gain Ga will be described later.

FIG. 6 is a front view of another antenna assembly used in the embodiment of FIG.

Referring to FIG. 6, this antenna assembly is
It includes the microstrip antenna 50 and the conductor plate 106. The antenna 50 includes an antenna element 51 including an open end 51a and a short circuit device 53, a through hole 52, and a side conductor plate 5 as in the microstrip antenna 1 of FIG.
4a, 54b and a main plate (not shown). However, since the antenna 50 is not provided with a side conductor plate facing the open end 51, the side conductor plates 54a and 54b are separated. Further, in the antenna element 51, the cutout portions 55a and 5 in which the conductor of the antenna element 51 is removed in the vicinity of the short circuit device 53 over the lengths L1 and L2.
5b is provided. These notches 55a and 55b
By providing, the resonance frequency f0 of the antenna 1 can be lowered, and the antenna 50 can be downsized. That is, in order to set the resonance frequency f0 to 930 MHz, the antenna 1 of FIG.
Although the distance D1 up to 55.3 mm is set to 55.3 mm, the antenna 51 of FIG. The distance D2 from 53 to the open end 51a is 4
It could be shortened to 8 mm.

FIG. 7 is a diagram showing an antenna pattern of the antenna assembly shown in FIG.

Referring to FIG. 7 together with FIG. 6, the ground plane dimension of the microstrip antenna 50 is E≈F≈50 mm, and the extending distance W2 of the conductor plate 106 from the end face of the antenna 50 is 30 mm. The front-direction antenna gain Ga of this antenna assembly increased by about 1.5 dB as compared with the case where the distance W2 is 0, that is, when the conductor plate 106 is not connected to the ground plane of the antenna 1 at high frequency. It is obvious that this increase in the antenna gain Ga can be similarly obtained in the antenna assembly of FIG. In addition, between the outer surface of the conductor plate 106 and the base plate of the antenna 50, the thickness t of the dielectric substrate is approximately 1.
Although there is a step difference of 6 mm, it has little effect on the antenna directivity pattern.

[0036]

As described above, in the radio selective call receiver of the present invention, the pair of conductor plates and the plurality of conductor connecting rods such as screws constitute a shield case surrounding the printed board and the electric / electronic parts. , And reduces unnecessary radio wave radiation from the first LO and the like to the outside of the receiver and stabilizes the circuit operation of the receiver.

Further, in this radio selective call receiver, the antenna ground plane is connected to one of the above-mentioned conductor plates bent in a crank shape at a high frequency, and the convex plane of this conductor plate is equivalently operated as the antenna ground plane. Not only can the area of the expensive microstrip substrate be saved only to the area of the antenna element, but also the thickness of the microstrip substrate can be changed to the housing portion for the components, so that the receiver can be miniaturized.

Further, when a side conductor plate is provided on the antenna element surface of the microstrip antenna so as to surround the antenna element, and the side conductor plate is connected to the ground plane by a through hole, the wireless selection of the screw or the like is performed. As long as the conductor structure forming the paging receiver is surrounded by the side conductor plates and the through holes, the radiation directivity pattern of the antenna is affected even if the position or size of the conductor structure changes. It is possible to increase the structural design freedom of this receiver.

If a cutout is provided in a part of the antenna element of the microstrip antenna, the resonance frequency f0 of the antenna can be lowered, so that the area of the antenna element is reduced and the receiver is miniaturized. You can

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a radio selective calling receiver of the present invention.

2 is a partially cutaway front view of the embodiment of FIG.

3 is a sectional view taken along line A1-A2 of FIG.

FIG. 4 is a sectional view taken along line B1-B2 of FIG. The wireless circuit 2 and the first LO 24 represent component mounting areas.

5 is a structural diagram of an antenna assembly used in the embodiment of FIG. (A) figure is a front view, (b) figure has shown the C1-C2 sectional view of (a) figure.

FIG. 6 is a front view of another antenna assembly used in the embodiment of FIG.

7 is a diagram showing an antenna pattern of the antenna assembly shown in FIG.

[Explanation of symbols]

 1 Microstrip antenna 2 Radio circuit 3 Waveform shaping circuit 4 LCD 5 Speaker 6 Decoder 7 Battery package 8 ROM 11 Antenna element 11a Open end 12, 13a, 14a Through hole 13 Short circuiter 14 Side conductor plate 15 Dielectric substrate 16 Ground plate 17 Feeding Point 18 Land 21,26 Amplifier 22,25 Bandpass filter 23 First frequency converter (first MIX) 24 First local oscillator (first LO) 27 Second frequency converter (second MIX) 28 Second local oscillator ( 2nd LO) 29 low-pass filter 30 demodulator 50 microstrip antenna 51 antenna element 52 through holes 54a, 54b side conductor plates 55a, 55b notch 101 case 102 frame 103a to 103e screw 104a to 104c nut 105 crimping test Flops 106 and 110 conductive plate 107 printed wiring board (printed circuit board) 108 electric and electronic parts 109 connecting line

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[Procedure amendment]

[Submission date] June 24, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

Still referring to FIG. 1, the wireless circuit 2
Is an amplifier 21 for amplifying the received signal from the microstrip antenna 1, a bandpass filter 22, and a first frequency converter (hereinafter referred to as a first MI) supplied with the output thereof.
X) 23. The first MIX 23 receives the amplified reception signal and the first local oscillation signal (frequency 90
8 MHz, signal level, about -15 dBm) to produce a first intermediate frequency signal (frequency 21.4 MHz). The first intermediate frequency signal has its unnecessary signal component removed by the bandpass filter 25 and further amplified by the amplifier 26, and then the second frequency converter (hereinafter, second MIX).
27. The second MIX 27 outputs the amplified first intermediate frequency signal and the second local oscillator (hereinafter, second LO) 28.
2nd local oscillation signal from (frequency 20.945 kHz)
And are mixed to produce the second intermediate frequency signal. The second intermediate frequency signal is converted into the digital signal by the demodulator 30 after the unnecessary signal component is removed by the low pass filter 29. Although this receiver further includes a power switch and the like, it is not shown because it does not relate to the gist of the present invention.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0035

[Correction method] Change

[Correction content]

Referring to FIG. 7 together with FIG. 6, the ground plane dimensions of the microstrip antenna 50 are E≈F≈50 mm.
The extension distance W2 of the conductor plate 106 from the end face of the antenna 50 is 30 mm. The front-direction antenna gain Ga of this antenna assembly increased by about 1.5 dB as compared with the case where the distance W2 is 0, that is, when the conductor plate 106 is not connected to the ground plane of the antenna 1 at high frequency. It is obvious that this increase in the antenna gain Ga can be similarly obtained in the antenna assembly of FIG. In addition, between the outer surface of the conductor plate 106 and the base plate of the antenna 50, the thickness t of the dielectric substrate ≈
Although there was a step of only 1.6 mm, it had almost no effect on the antenna directivity pattern. It should be noted that in the embodiment shown in FIGS. 2 to 6, the through hole 13a that constitutes the short circuiter 13 is formed.
May be on the open end 11a side. 2 to 6
In the embodiment, instead of the case 101, the outer casing may be constituted by a frame and a metal plate as disclosed in, for example, Japanese Patent Laid-Open No. 2-116228.

Claims (17)

[Claims] 1. An antenna element composed of a first conductor thin film formed on one surface of a flat dielectric substrate, and a base plate composed of a second conductor thin film formed on the other surface of the dielectric substrate, and the antenna. A microstrip antenna having a short-circuit means for connecting one end of the element and the ground plane to generate a reception signal in response to a radio selective call signal electromagnetic wave, and in response to the reception signal and a local oscillation signal from a local oscillator. Radio frequency circuit means for producing an intermediate frequency signal and further producing a digital signal from the intermediate frequency signal, and call control for making a call in response to a match between a call signal included in the digital signal and a call number previously assigned to itself. Means for mechanically holding a part of the receiver circuit including the local oscillator, and between elements of the receiver circuit. A printed wiring board that selectively forms an electrical connection of the printed wiring board, a shield member that electromagnetically covers the printed wiring board so as to prevent leakage of unnecessary electromagnetic waves from the printed wiring board, and the main plate on the outer surface of the shield member. A radio selective calling receiver, characterized in that it is provided with an antenna supporting means connected to a part in a high frequency manner. 2. The microstrip antenna is a half-size microstrip antenna in which thin conductors formed on both surfaces of the planar dielectric substrate are selectively etched and removed and the short-circuit means is formed by a through hole. The antenna element is the conductor formed on one surface of the dielectric substrate, the ground plane is the conductor formed on substantially the entire other surface of the dielectric substrate, and the short-circuit means 2. The radio selective call receiver according to claim 1, wherein is a plurality of first through-hole means for connecting the vicinity of one side of the quadrilateral of the antenna element and the ground plane. 3. The side conductor film, wherein the microstrip antenna is a surface of the dielectric substrate on which the antenna element is formed and is formed outside the antenna element and is made of a thin film conductor, and the side conductor film. The radio selective call receiver according to claim 2, further comprising a plurality of second through-hole means for connecting the main board and the ground plane. 4. The radio selective call receiver according to claim 2, wherein the antenna element has a pair of notches in the vicinity of the short-circuit means in a direction in which the short-circuit means extends. 5. The radio selective call receiver according to claim 2, wherein the shield member including the connection surface of the ground plane has a larger area than the ground plane. 6. The radio selective call receiver according to claim 5, wherein the shield member is bent in a crank shape, and the base plate is accommodated in a recess of the crank-shaped bent portion. 7. A microstrip antenna for generating a reception signal from a radio selective call signal, the microstrip antenna having an antenna element, a ground plane, and one end of the antenna element and a short-circuiting means for connecting the ground plane to each other, and the reception signal and a local oscillator. Radio frequency circuit means for generating an intermediate frequency signal in response to the local oscillation signal and further generating a digital signal from the intermediate frequency signal, and for matching a calling signal included in the digital signal and a calling number pre-assigned to itself. A radio selective call receiver comprising a call control means for making a call in response to mechanically holding a part of a receiver circuit including the local oscillator and selecting an electrical connection between elements of the receiver circuit. A printed wiring board to be formed in an integrated manner, a pair of conductor plates arranged with the printed wiring board sandwiched therebetween, and a pair of these conductor plates. A plurality of connecting means for electrically connecting to each other at regular intervals and in the periphery thereof, and an antenna supporting means for connecting the ground plane to one outer surface of the conductor plate in a high frequency and mechanical manner. Wireless selective call receiver. 8. The microstrip antenna is a half-size microstrip antenna in which thin conductors formed on both surfaces of the planar dielectric substrate are selectively etched and removed and the short-circuit means is formed by a through hole. The antenna element is the conductor formed on one surface of the dielectric substrate, the ground plane is the conductor formed on substantially the entire other surface of the dielectric substrate, and the short-circuit means 8. The radio selective call receiver according to claim 7, wherein is a plurality of first through-hole means for connecting the vicinity of one side of the quadrilateral of the antenna element and the ground plane. 9. The microstrip antenna means includes a side conductor formed on the surface of the dielectric substrate on which the antenna element is formed, the side conductor being formed of a conductor arranged on the dielectric substrate outside the antenna element. 9. The radio selective calling receiver according to claim 8, further comprising a plurality of second through-hole means for connecting the side conductors and the ground plane. 10. The connecting means comprises at least the second
10. The radio selective calling receiver according to claim 9, wherein the radio selective calling receiver is arranged further outward than a part of the through-hole means. 11. The conductor plate connected to the ground plane,
The radio selective call receiver according to claim 7, wherein the radio selective call receiver has an area larger than that of the ground plane. 12. The conductor plate connected to the ground plane,
9. The radio selective calling receiver according to claim 8, wherein the radio selective calling receiver has an area larger than that of the ground plane. 13. The radio according to claim 12, wherein the conductor plate connected to the base plate has a crank-shaped bent portion, and the base plate is accommodated in a recess of the bent portion. Selective call receiver. 14. The conductive thin film of the antenna element,
9. The radio selective call receiver according to claim 8, further comprising a notch portion extending in an important direction of the extension of the antenna element. 15. The radio selective call receiver according to claim 7, wherein said antenna supporting means includes a pressure-bonding tape inserted between said ground plane and one surface of said conductor plane. 16. A third means for connecting the microstrip antenna means to a land means insulated from the conductor thin film formed on the other surface of the dielectric substrate and the ground plane, and the antenna element and the land means.
Through-hole means, the printed wiring board further includes at least an input end of the radio frequency circuit means, and the radio selective call receiver connects the land means and the input end of the radio frequency circuit means. 9. The radio selective call receiver according to claim 8, further comprising means. 17. The radio selective calling receiver further includes battery package means for supplying power to the receiver circuit, wherein the battery package means includes a convex portion formed by the bent portion and another conductor plate. The radio selective call receiver according to claim 13, wherein the radio selective call receiver is housed in the space.