JPH08186420A - Print antenna - Google Patents

Abstract

PURPOSE: To simultaneously use a print antenna at plural frequencies by providing respectively specified dielectric substrate, resonance circuit and ground substrate. CONSTITUTION: This print antenna is provided with a dielectric substrate 1a forming a conductor pattern 10 to be resonated at a first frequency, resonance circuit 11 inserted into the intermediate part of the conductor pattern 10 so as to be resonated at a second frequency, and ground substrate 1b vertically arranged on the dielectric substrate 1a. The conductor pattern 10 is separated into first and second antenna elements 10a and 10b by the resonance circuit 11 and respectively function as the ground plane antennas of 1/4λ. Since the resonance circuit 11 is resonated to the second frequency, it is equivalent with the state of opening the first antenna 10a to the second frequency and by setting its length L2 so as to resonate to second antenna element 10a at the second frequency, this print antenna is resonated at the second frequency. Since the conductor pattern 10 is resonated to the first frequency, this print antenna can be used as a two-frequency sharing antenna.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-frequency shared printed antenna that can be used simultaneously at a plurality of frequencies.

[0002]

2. Description of the Related Art As an antenna used in a vehicle-mounted radio, a frequency switching type glass antenna installed in a window glass of a vehicle as shown in FIG. 8 is known. In FIG. 8, a frequency switching type glass antenna 30
Is a first radiation pattern 31 and a second radiation pattern 32
, A grounding pattern 33, and a connector type jumper wire 34 that connects the first radiation pattern 31 and the second radiation pattern 32, and is installed on the window glass 35 of the vehicle. The frequency switchable glass antenna 20 is connected to an on-vehicle radio device (not shown) via the coaxial cable 20, the center conductor 20a of the coaxial cable 20 is connected to the second radiation pattern 32, and the outer conductor 20b is grounded. Is connected to the pattern 33.

When the frequency switching type glass antenna 30 is operated at the first frequency, the connector type jumper wire 34 short-circuits the first radiation pattern 31 and the second radiation pattern 32 to operate at the second frequency. At this time, the connector type jumper wire 34 is removed to open the first radiation pattern 31.

However, the frequency switching type glass antenna 30 can resonate at two frequencies of the first frequency and the second frequency, but the connector type jumper wire 34 is attached and detached to switch between the first frequency and the second frequency. It must be used at two frequencies at the same time. Therefore, it is necessary to connect or disconnect the connector type jumper wire 34 in accordance with the communication frequency, which is troublesome.

Further, this frequency switching type glass antenna 3
When 0 is installed on the rear window glass of the vehicle, the rear window glass itself is quite inclined, so the mutual polarization system does not match whether the communication partner is vertical polarization or horizontal polarization, There is a problem that the loss is large.

[0006] It is an object of the present invention to provide a multi-frequency shared printed antenna which can be used simultaneously at a plurality of frequencies.

[0007]

FIG. 1 showing a first embodiment.
When the inventions of claims 1 and 2 are described in association with the invention, the invention of claim 1 is characterized in that the conductor pattern 10 resonates at the first frequency.
A dielectric substrate 1a having a structure formed therein and a resonance circuit 11 which is inserted into an intermediate portion of the conductor pattern 10 and resonates at a second frequency.
And a ground substrate 1b arranged vertically to the dielectric substrate 1a, thereby achieving the above object. The printed antenna according to claim 2 has the resonance circuit 11 and the chip inductor 1.
1a and the chip capacitor 11b are connected in parallel. The invention of claim 3 will be described in association with FIG. 3 showing a second embodiment. The invention of claim 3 is characterized by a plurality of conductor patterns (10a, 10a) which resonate at a first frequency.
b) formed on the dielectric substrate 1 and a plurality of resonance circuits (11a, 11b) which are inserted in the intermediate portions of the conductor patterns and resonate at the second frequency, and are arranged perpendicular to the dielectric substrate 1a. Ground substrate 1b.

[0008]

The conductor pattern 10 having the length L3 resonates at the first frequency. On the other hand, the conductor pattern 10 is separated into the first antenna element 10a and the second antenna element 10b by the resonance circuit 11, and each functions as a 1 / 4λ ground plane antenna. Since the resonance circuit 11 resonates at the second frequency, it becomes equivalent to the state where the first antenna element 10a is opened for the second frequency, and its length is set so that the second antenna element 10b resonates at the second frequency. L2
By setting, the printed antenna resonates at the second frequency. That is, this printed antenna can be used as a dual frequency antenna simultaneously at the first frequency and the second frequency. In addition, a plurality of conductor patterns that resonate at the first frequency are formed on one dielectric substrate 1a, and a resonance circuit that resonates at the second frequency is inserted in the middle of each conductor pattern to form a dielectric substrate 1a. The ground substrate 1b is arranged vertically to form a space diversity antenna to perform diversity reception.

[0009]

【Example】

First Embodiment FIG. 1 is a circuit diagram showing the structure of the dual frequency printed antenna of the first embodiment. Dual frequency printed antenna 1
Is a dielectric substrate 1a on which the monopole element 10 is printed.
And a ground substrate 1b. Note that the dielectric substrate 1a is actually arranged perpendicular to the ground substrate 1b.
The resonance circuit 1 is provided in the middle of the monopole element 10 having the length L3.
1 is inserted and has a length L1 and a width W1.
0a and a second antenna element 10b having a length L2 and a width W2. The resonance circuit 11 is a chip inductor 11
It is a parallel circuit of a and the chip capacitor 11b. The dual-frequency printed antenna 1 is connected via a coaxial cable 20 to an in-vehicle wireless device (not shown). Coaxial cable 2
The center conductor 20a of 0 is connected to the base end of the monopole element 10, and the outer conductor 20b of the coaxial cable 20 is the ground conductor 1.
connected to b.

The monopole element 10 having the length L3 resonates at the first frequency f1. At this time, the length L3 is about 1 / 4λ1.
Further, the resonance circuit 11 resonates at the second frequency f2. Further, in order to resonate the second antenna element 10b alone at the second frequency f2, the length L2 thereof is set to about ¼λ2. Dual frequency printed antenna 1 configured in this way
Since the resonance circuit 11 resonates at the second frequency f2, it becomes equivalent to the state where the first antenna element 10a is opened for the second frequency f2, and the resonance circuit 11 resonates at the first frequency f1 and at the same time the second frequency f2. Also resonates.

The bandwidth of the first resonance frequency f1 is determined by the width W1 of the first antenna element 10a, and the bandwidth can be increased by increasing W1. Also, the second
The bandwidth of the resonance frequency f2 is determined by the width W2 of the second antenna element 10b and the Q representing the sharpness of resonance of the resonance circuit 11, and the width W2 is increased or the width Q is decreased to increase the bandwidth. Alternatively, or both may be adjusted.

FIG. 2 shows a return loss characteristic of the dual frequency printed antenna 1 of the first embodiment. From this characteristic diagram, the monopole element 10 has the first frequency f1 = 850 MH.
While resonating at z, the resonance circuit 11 and the second antenna element 10b resonate at the second frequency f2 = 1450 MHz,
The dual frequency printed antenna 1 has two frequencies f1 and f2.
Indicates that they can be used at the same time. Further, by adjusting the length L3 of the monopole element 10 and the length L2 of the second antenna element 10b, the two frequencies f1 and f2 can be arbitrarily set, and the width W1 of the first antenna element 10a and the second frequency f2 can be set. By adjusting the width W2 of the antenna element 10b, the bandwidths of the two resonance frequencies f1 and f2 can be set arbitrarily. Further, the resonance circuit 11 has a chip inductor 1 which is less susceptible to errors and variations in inductance and capacitance.
Since 1a and the chip capacitor 11b are used, fluctuations in the resonance frequency can be reduced, and stable communication becomes possible.

-Second Embodiment- FIG. 3 is a perspective view showing the configuration of the second embodiment. In the second embodiment, a space diversity antenna is constructed using the dual frequency printed antenna 1 shown in FIG. The dielectric substrate 1a is vertically installed on the ground substrate 1b, and the first antenna element 10a, the resonance circuit 11, and the second antenna element 10b shown in FIG. 1 are mounted on the dielectric substrate 1a.
2 sets, which are separated from each other by about 1/4? These two sets of antenna elements are respectively connected to an on-vehicle radio device (not shown) via two coaxial cables 20. Center conductor 20a of two coaxial cables 20
Are respectively connected to the base ends of the corresponding second antenna elements 10b, and the outer conductors 20b are both connected to the ground conductor 1b.

The antenna of the second embodiment has the same characteristics as the antenna of the first embodiment described above,
Can be used simultaneously at one frequency f1 and f2. In addition, since the space diversity antenna corresponding to diversity reception is integrally configured, it can be installed anywhere in the vehicle,
Wiring of the coaxial cable can be done in one place, and the number of wiring steps can be reduced. Further, since the base station of the in-vehicle wireless device has an antenna installed vertically to the ground plane and has vertical polarization, if this antenna is installed in the vehicle so that the dielectric substrate 1a is perpendicular to the ground plane, the base station Polarization directions match with those of the station, and high reception gains can be obtained. Furthermore, since two sets of antenna elements are formed by printing on one dielectric substrate 1a,
In addition to being easy to manufacture, product variations are reduced.

-Third and Fourth Embodiments- FIG. 4 is a perspective view showing the construction of the third embodiment, and FIG. 5 is a perspective view showing the construction of the third embodiment. Both of the third and fourth embodiments are the dual frequency antenna 1 shown in FIG.
This is a modification of the above-described second embodiment in which the space diversity antenna is configured by using. In the third embodiment, as shown in FIG. 4, the first antenna element 10a and the second antenna element 10a
The antenna element 10b and the antenna element 10b are arranged on a straight line,
In the third embodiment, as shown in FIG. 5, the first antenna element 10
a and the second antenna element 10b are arranged in an L shape. The antennas of these embodiments have the same characteristics and effects as those of the second embodiment described above, but the third embodiment in which the two antenna elements 10a and 10b are arranged on a straight line as shown in FIG. The example has relatively better characteristics and higher gain than the other second and fourth embodiments.

-Fifth Embodiment- FIG. 6 is a circuit diagram showing a structure of a three-frequency shared printed antenna according to a fifth embodiment. This three-frequency shared printed antenna 1A has a resonant circuit 12 inserted in the middle of the second antenna element 10b of the two-frequency shared printed antenna 1 shown in FIG. 1, and is similar to the first embodiment shown in FIG. The same parts are designated by the same reference numerals, and different points will be mainly described. By inserting the resonance circuit 12, the second circuit having the length L5 and the width W2 is inserted.
The antenna element 10b is separated into a third antenna element 10c having a length L4 and a width W4. The resonance circuit 12 is a parallel circuit of a chip inductor 12a and a chip capacitor 12b.

The monopole element 10 having the length L3 resonates at the first frequency f1, and the length L3 at this time is about ¼λ1.
Also, the second and third antenna elements 10b having the length L2,
1c resonates at the second frequency f2, at which time the length L2 is about 1
/ 4λ2. The resonance circuit 11 resonates at the second frequency f2 as described above. The resonance circuit 12 resonates at the third frequency f3. In addition, the third antenna element 10c
In order to resonate at the frequency f3, its length L4 is about 1 /
Set to 4λ3. In the three-frequency shared printed antenna 1A thus configured, the resonance circuit 12 has the third frequency f3.
Since it resonates with the third frequency f3, it becomes equivalent to the state where the first antenna element 10a and the second antenna element 10b are opened with respect to the third frequency f3, and resonates with the third frequency f3, and at the same time as described above, the first frequency f1 And also resonates with the second frequency f2. That is, this three-frequency shared print antenna 1A
Can be used simultaneously at three frequencies f1, f2, f3. In addition, the resonance circuit 12 has a chip inductor 12a with less variation in inductance and capacitance.
Since the chip capacitor 12b is used, the resonance frequency fluctuation can be reduced and stable communication becomes possible.

The bandwidth of the third resonance frequency f3 is determined by the width W4 of the third antenna element 10c and the Q of the resonance circuit 12. To widen the bandwidth, the width W4 is increased or Q is decreased. Alternatively, or both may be adjusted.

-Sixth Embodiment- FIG. 7 is a perspective view showing the structure of the sixth embodiment. In the sixth embodiment, a space diversity antenna is constructed by using the three-frequency shared printed antenna 1A shown in FIG. The dielectric substrate 1a is installed vertically on the ground substrate 1b, and the first to third antenna elements 10a to 10c and the resonance circuits 11 and 12 shown in FIG. 6 are arranged on the dielectric substrate 1a.
The sets are printed at a distance of about 1 / 4λ to 1 / 2λ from each other. These two sets of antenna elements are respectively connected to an on-vehicle radio device (not shown) via two coaxial cables 20. The center conductors 20a of the two coaxial cables 20 are respectively connected to the base ends of the corresponding third antenna elements 10c, and the outer conductors 20b are both connected to the ground conductor 1b.

The antenna of the sixth embodiment has the same characteristics as the antenna of the fifth embodiment, and can be used simultaneously at three frequencies f1, f2 and f3. Further, since the space diversity antenna is configured, the same effect as that of the second embodiment described above can be obtained.

[0021]

As described above, according to the first aspect of the invention, a conductor pattern that resonates at the first frequency is formed on the dielectric substrate, and the second pattern resonates at the intermediate portion of the conductor pattern. Since the resonance circuit is inserted and the ground substrate is arranged perpendicularly to the dielectric substrate, it can be used simultaneously at a plurality of frequencies, and each frequency and resonance bandwidth can be set arbitrarily. According to the invention of claim 2, since the resonance circuit is configured by connecting the chip inductor and the chip capacitor in parallel, it is possible to reduce the fluctuation of the resonance frequency and to perform stable communication. According to the invention of claim 3, a plurality of conductor patterns that resonate at the first frequency are formed on one dielectric substrate, and
Since a plurality of resonance circuits that resonate at the second frequency are inserted in the middle of each conductor pattern and the ground substrate is arranged perpendicular to the dielectric substrate, it is possible to use at a plurality of frequencies simultaneously.
Since the space diversity antenna is integrally configured, the installation location in the vehicle is not selected and the coaxial cable can be wired in only one place, and the number of wiring steps can be reduced. In addition, the base station of the in-vehicle radio has an antenna installed vertically to the ground plane, and since it is vertically polarized, if this antenna is installed in the vehicle so that the dielectric substrate is perpendicular to the ground plane, the base station And the polarization directions match, and high reception gain can be obtained. Furthermore, since a plurality of antenna elements are printed and formed on a single dielectric substrate, manufacturing is simplified and product variations are reduced.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a dual frequency printed antenna according to a first embodiment.

FIG. 2 is a diagram showing a return loss characteristic of the dual frequency printed antenna according to the first embodiment.

FIG. 3 is a perspective view showing a second embodiment in which a space diversity antenna is configured by using a dual-frequency print antenna.

FIG. 4 is a perspective view showing a third embodiment in which a space diversity antenna is configured by using a dual frequency print antenna.

FIG. 5 is a perspective view showing a fourth embodiment in which a space diversity antenna is configured by using a dual frequency print antenna.

FIG. 6 is a circuit diagram showing the configuration of a triple frequency printed antenna according to a fifth embodiment.

FIG. 7 is a perspective view showing a sixth embodiment in which a space diversity antenna is configured by using a print antenna for three frequencies.

FIG. 8 is a diagram showing a conventional glass antenna.

[Explanation of symbols]

 1 2 Frequency Common Print Antenna 1A 3 Frequency Common Print Antenna 1a Dielectric Substrate 1b Ground Substrate 10 Monopole Element 10a First Antenna Element 10b Second Antenna Element 10c Third Antenna Element 11, 12 Resonant Circuit 11a, 12a Chip Inductor 11b, 12b Chip capacitor 20 Coaxial cable 20a Center conductor 20b Jacket conductor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H04B 7/02 Z

Claims (3)

[Claims] 1. A dielectric substrate having a conductor pattern resonating at a first frequency, a resonance circuit inserted at an intermediate portion of the conductor pattern and resonating at a second frequency, and a dielectric circuit perpendicular to the dielectric substrate. A printed antenna, comprising: a ground substrate provided. 2. The printed antenna according to claim 1, wherein the resonant circuit is configured by connecting a chip inductor and a chip capacitor in parallel. 3. A dielectric substrate on which a plurality of conductor patterns that resonate at a first frequency are formed, a plurality of resonance circuits that are inserted in an intermediate portion of each conductor pattern and resonate at a second frequency, and the dielectric substrate. A printed antenna comprising: a ground substrate disposed vertically to a body substrate.