JP3180683B2 - Surface mount antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microstrip antenna, and more particularly, to a microstrip antenna that supports a plurality of frequency bands and is capable of selecting a polarization.

[0002]

2. Description of the Related Art A conventional microstrip antenna will be described with reference to FIGS. The microstrip antenna 100 shown in FIGS. 8 and 9 includes a substrate 101 made of a dielectric material, a radiation electrode 102 formed on one main surface of the substrate 101, and a ground electrode 103 formed on the other main surface of the substrate 101. Consists of A power supply through-hole 104 is provided at a position corresponding to the radiation electrode 102 on the substrate 101. A connector 105 for supplying power to the radiation electrode 102 is inserted into the power supply through hole 104 so as to penetrate from the other main surface side of the substrate 101. The connector 105 is electrically connected to the radiation electrode 102 by the solder 106a, and is fixed to the substrate 101 by the solder 106a and the solder 106b. The microstrip antenna 100 receives a circularly polarized wave, and the radiation electrode 102 is provided with a degenerate separation section 102a as shown in FIG.

Next, a microstrip antenna 110 shown in FIGS. 10 and 11 is a substrate 11 made of a dielectric material.
1 and a radiation electrode 11 formed on one main surface of the substrate 111.
2 and a ground electrode 11 formed on the other main surface of the substrate 111.
3 Then, a power supply through-hole 114 is provided at a position corresponding to the radiation electrode 112 on the substrate 111.
A connector 115 for supplying power to the radiation electrode 112 is inserted into the power supply through hole 114 so as to penetrate from the other main surface side of the substrate 111. Connector 115 is solder 1
Conduction with the radiation electrode 112 is performed by 16a, and is fixed to the substrate 111 by solder 116a and solder 116b. The microstrip antenna 110 receives linearly polarized waves and differs from the radiation electrode 102 of the microstrip antenna 100 in FIG.
As shown in FIG. 0, the radiation electrode 112 is not provided with the degenerate separation portion.

[0004]

However, the microstrip antennas of the above-mentioned conventional examples have different frequency bands to receive and different polarizations to receive. When trying to receive such distant frequency bands simultaneously, two microstrip antennas are arranged side by side. Two radiation electrode patterns are formed on one substrate, and a microstrip antenna that feeds each radiation electrode is provided. It can be used.

However, in either case, two radiating electrodes corresponding to different frequency bands must be arranged at a sufficient interval so as not to interfere with each other. Each had to be provided with a power supply means such as a connector. This has hindered miniaturization of the antenna.

Accordingly, it is an object of the present invention to provide a miniaturized microstrip antenna that can handle a plurality of frequency bands and can select a polarization.

[0007]

In order to achieve the above object, a microstrip antenna according to the present invention comprises:
A substrate composed of two main surfaces separated in the thickness direction and parallel to each other, and four side surfaces connecting the main surfaces, a first radiation electrode formed on one main surface of the substrate, First
At least two second radiation electrodes, which are located in the periphery of the radiation electrode and are formed in directions perpendicular to each other with respect to a center point of the first radiation electrode, and a ground electrode formed on the other main surface of the substrate; A power supply through-hole formed at a position corresponding to the first radiation electrode of the substrate between two main surfaces of the substrate, and a ground formed at a position corresponding to the second radiation electrode of the substrate. And at least two capacitive coupling portions for capacitively coupling the first radiation electrode and the second radiation electrode.

Also, they are separated from each other in the thickness direction and are parallel to each other.
Composed of two main surfaces and four side surfaces connecting the main surfaces.
And a first substrate formed on one main surface of the substrate.
A radiating electrode, which is located around the first radiating electrode,
A substantially L-shaped small part formed at an interval from the first radiation electrode
At least one second radiating electrode and the other main surface of the substrate
And a ground electrode formed between the two main surfaces of the substrate.
A power supply formed at a location of the substrate corresponding to the first radiation electrode
A through hole for electricity, corresponding to the second radiation electrode of the substrate;
A ground through-hole formed at a location, the first radiation electrode,
At least two for capacitively coupling with the second radiation electrode;
And two capacitive coupling parts .

The capacitive coupling portion is formed to protrude from the first radiation electrode in the direction of the second radiation electrode, and is formed to protrude from the second radiation electrode in the direction of the first radiation electrode. The second comb-shaped electrode intersects with each other.

[0010] Further, the capacitive coupling section is formed of a chip type capacitor.

Thus, the first radiation electrode acts as a microstrip antenna corresponding to one frequency band, and the first radiation electrode and the second radiation electrode are capacitively coupled to form another microstrip line. That is, it functions as a microstrip antenna corresponding to another frequency band. Therefore, a microstrip antenna corresponding to a plurality of frequency bands can be obtained on one substrate, and only one power supply through hole is required for power supply.
Miniaturization is achieved.

Further, since the second radiation electrode is formed in a substantially L-shape and the effective area of the microstrip antenna is increased, the gain of the antenna is also increased.

Further, since the capacitive coupling portion is formed in a comb shape and a high capacitance can be obtained only by the electrode pattern, the height can be reduced and the capacitance value can be easily adjusted by a method such as trimming.

In the case where the capacitive coupling section is composed of a chip capacitor, a chip capacitor having a desired capacitance value may be attached, and a microstrip antenna having high frequency band accuracy and high polarization selectivity can be obtained. Can be

[0015]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2, reference numeral 1 denotes a microstrip antenna, which is made of a dielectric material and includes two main surfaces separated in a thickness direction and parallel to each other, and four side surfaces connecting the main surfaces. Substrate 11, a first radiation electrode 12 formed on one main surface of the substrate 11, and a peripheral portion of the first radiation electrode, which are perpendicular to each other with respect to a center point of the first radiation electrode. Between the two second radiation electrodes 13 and 14 formed, the ground electrode 15 formed on the other main surface of the substrate 11, and the two main surfaces of the substrate 11,
A through-hole 16 for power supply formed at a position corresponding to the first radiation electrode 12 of the substrate 11, and also formed at a position corresponding to the second radiation electrode 13 of the substrate 11 between the two main surfaces of the substrate 11. A plurality of through holes 17 and a capacitive coupling unit 1 for capacitively coupling the first radiation electrode 12 and the second radiation electrodes 13 and 14.
8a and 18b.

A connector 19 is inserted into the power supply through hole 16 from the other main surface side of the substrate 11 as a coaxial line for supplying power to the first radiation electrode 12. It is electrically connected to the radiation electrode 12 and is fixed to the substrate 11 by the solder 20a and the solder 20b.

The second radiation electrodes 13 and 14 are formed in the through holes 1.
7 is connected to the ground electrode 15.

The first radiation electrode 12 has a substantially square shape.
Substantially strip-shaped second radiation electrodes 13 and 14 are arranged so as to face each of the two sides of the radiation electrode 12. The first comb-shaped electrode 2 is formed so as to protrude from the first radiation electrode 12 in the direction of the second radiation electrodes 13 and 14 in a comb-like manner.
1 and 22 and the first radiation electrodes 13 and 14 respectively.
The second comb-shaped electrodes 23 and 24 formed so as to protrude in the direction of the radiation electrode 12 in a comb shape are arranged so as to intersect with each other to form capacitive coupling portions 18a and 18b. Thereby, the first radiation electrode 12 and the second radiation electrodes 13 and 14 are formed.
And the first radiation electrode 12 and the second radiation electrodes 13 and 14 are capacitively coupled.

First radiation electrode 12, second radiation electrode 13, 1
4, and the ground electrode 15 is formed by patterning a metal film formed on both main surfaces of the substrate 11 by etching or by printing and firing a conductive paste on both main surfaces of the substrate 11. You.

In the microstrip antenna 1 thus configured, the first radiation electrode 12 functions as a microstrip antenna corresponding to one frequency band (high frequency side), and the first radiation electrode 12 and the second radiation electrode The whole including the electrodes 13 and 14 functions as a microstrip antenna corresponding to another frequency band (low frequency side).

Next, the results of an experiment conducted on the first embodiment will be described. FIG. 3A shows a Smith chart showing experimental results of impedance characteristics in the first embodiment, and FIG. 3B shows return loss characteristics. In this experiment, the distance between the center point O of the first radiation electrode 12 and the feed through hole 16 was L1, and the first radiation electrode 1
The length of one side of 2 is L12. Here, the power supply through hole 1
6 is arranged at a position shifted from the center point O in the direction of the second radiation electrode 13 by the length of L1 represented by L1 ≒ (1/6) × L12, at which point the first radiation electrode 12 is Powered. The dielectric substrate 11 used had a relative dielectric constant of 10.5, and the capacitance value of the capacitive coupling portion 18a was set to 3.0 pF, and the capacitance value of the capacitive coupling portion 18b was set to 2.5 pF. In addition, L12 = λg1 / 2 is set, and the first radiation electrode 12 and the second
The distance between the farthest ends of the radiation electrode 13 was set as L13 = λg2 / 2. Note that λg1 is the wavelength on the high frequency side, and λg2 is the wavelength on the low frequency side.

As shown in FIGS. 3 (a) and 3 (b), two resonance characteristics resonating at f1 = 1.57 GHz and f2 = 2.56 GHz are obtained. It was confirmed that it corresponded to the frequency band.

Next, a microstrip antenna 30 according to a second embodiment of the present invention will be described with reference to FIG. The microstrip antenna 1 shown in FIG.
The same components as those described above are denoted by the same reference numerals and description thereof will be omitted.

The microstrip antenna 30 is different from the microstrip antenna 1 in that the microstrip antenna 30 is located in the periphery of the first radiation electrode and is formed in a substantially L-shape so as to surround the first radiation electrode 12. 33 is located here.

As described above, by forming the second radiation electrode 33 in a substantially L-shape, the entire effective area including the first radiation electrode 12 and the second radiation electrode 33 becomes large.
The gain of the microstrip antenna 30 is also improved.

Next, a microstrip antenna 40 according to a third embodiment of the present invention will be described with reference to FIG. The microstrip antenna 1 shown in FIG.
The same components as those described above are denoted by the same reference numerals and description thereof will be omitted.

The microstrip antenna 40 is different from the microstrip antenna 1 in that second radiation electrodes 43 and 44 are newly formed so as to surround all four sides of the first radiation electrode 12 formed in a substantially square shape. Here, the capacitive coupling portions 18c and 18d are disposed between the first radiation electrode 12 and the second radiation electrodes 43 and 44, respectively.

This microstrip antenna 40
The first radiating electrode 12 and the second radiating electrodes 43 and 4 correspond to one frequency band, and the first and second radiating electrodes 12 and 13 and 14 correspond to another frequency band.
4 functions as a microstrip antenna corresponding to another frequency band.

Although not shown, the microstrip antenna 40 also has the same structure as the microstrip antenna 30 of the second embodiment.
The radiation electrodes 13 and 14 may be combined to form a substantially L shape, or the second radiation electrodes 43 and 44 may be combined to form a substantially L shape.

In the microstrip antennas described in the first to third embodiments, the first radiation electrode and the second radiation electrode are capacitively coupled by the capacitive coupling portion. By shifting the frequency band or trimming the comb-shaped electrode forming the capacitive coupling part, the frequency band on the low frequency side to be received can be easily adjusted, and the polarization on the low frequency side can also be selected. Can be.

For example, in the microstrip antenna 1 shown in the first embodiment, two capacitive coupling units 1
By shifting the formation positions of 8a and 18b or making the capacitance values different, a phase difference θ occurs between the resonance due to the capacitive coupling of the capacitive coupling unit 18a and the resonance due to the capacitive coupling of the capacitive coupling unit 18b. When the angle approaches θ = 90 °, the polarization on the low frequency side becomes a circular polarization, and when the angle approaches θ = 0 °, the polarization on the low frequency side becomes a linear polarization. In FIG. 3 (a) showing the experimental results of the first embodiment, it can be seen that a narrow portion of the Smith chart on the low frequency side f1 is indicated by a triangle. This represents the state of a wave. That is, the formation position and the capacitance value of the two capacitive coupling portions 18a and 18b are set such that the phase difference θ between the resonance due to the capacitive coupling of the capacitive coupling portion 18a and the resonance due to the capacitive coupling of the capacitive coupling portion 18b is close to 90 °. Is set as the microstrip antenna 1.

Since the capacitive coupling portion formed in a comb shape can be formed simultaneously with the first radiation electrode and the second radiation electrode, the capacitance coupling portion is easy to form, and the thickness is small. The height can be reduced as well as the radiation electrode.

Further, the capacitive coupling section includes the first to third capacitors described above.
In the embodiment shown in FIG.
As shown in FIG. 5, the chip type capacitor 38 may be used. In this case, since a chip-type capacitor having a fixed capacitance value can be selected and arranged, an antenna corresponding to a desired frequency band and a desired polarization can be easily and accurately formed, and frequency adjustment and polarization can be performed. The wave reselection step is not required. In FIG. 6, components other than the chip-type capacitor 38 are the same as those of the microstrip antenna 30 shown in the second embodiment, and therefore, are denoted by the same reference numerals and description thereof is omitted.

The capacitive coupling section is not limited to the above-described embodiment. For example, although not particularly shown, at a position corresponding to the capacitive coupling section between the first radiation electrode and the second radiation electrode, It may be a capacitive coupling portion having a laminated structure in which a dielectric layer is interposed between the first radiation electrode and the second radiation electrode, and may be deformed according to the purpose and use of the microstrip antenna.

The first radiating electrode 12 described in each embodiment has a shape having a contraction separating portion 12a as shown in FIG. 7, and selects a high-frequency side polarized wave received by the first radiating electrode 12. You can also. In FIG. 7, components other than the contracted body separating portion 12a are the same as those of the microstrip antenna 1 shown in the first embodiment, and therefore, are denoted by the same reference numerals and description thereof is omitted.

As described above, in the microstrip antenna of the present invention, the polarization can be set in the first radiation electrode corresponding to one frequency band (high frequency side), and the other frequency band (low frequency side). The polarization can be selected in the whole including the first radiation electrode and the second radiation electrode corresponding to.

In the above embodiment, the first radiation electrode has a substantially square shape, but may have a substantially circular shape.

In the above embodiment, the second radiation electrode and the ground electrode are connected by a plurality of through holes.
If the radiation electrode is grounded at a high frequency, the number of through holes can be appropriately selected and determined.

The microstrip antenna according to the present invention is not limited to the above embodiment, but can be variously modified within the scope of the invention.

[0040]

As described above, in the microstrip antenna according to the present invention, the first radiation electrode functions as a microstrip antenna corresponding to one frequency band, and the first radiation electrode and the second radiation electrode are capacitively coupled. As a result, another microstrip line is formed, and functions as a microstrip antenna corresponding to another frequency band. Therefore, a microstrip antenna corresponding to a plurality of frequency bands is formed on one substrate. In addition, since only one power supply through hole is required for power supply, miniaturization is achieved.

The second radiation electrode is formed in a substantially L shape.
In this case , the effective area of the microstrip antenna becomes large, so that the antenna gain also becomes large.

Further, the field capacitive coupling portion is formed in a comb shape
In this case , since a high capacitance can be obtained only by the electrode pattern, the height can be reduced, the capacitance value can be easily adjusted by a method such as trimming, the frequency band to be received is highly accurate, and the polarization can be selected.

When the capacitive coupling section is formed of a chip capacitor, a chip capacitor having a desired capacitance value may be attached, and a microstrip antenna with high frequency band accuracy and selectable desired polarization can be obtained. .

[Brief description of the drawings]

FIG. 1 is a plan view showing a structure of a microstrip antenna according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

3A is a Smith chart and FIG. 3B is a return loss characteristic diagram showing characteristics of the microstrip antenna according to the first embodiment of the present invention.

FIG. 4 is a plan view showing a structure of a microstrip antenna according to a second embodiment of the present invention.

FIG. 5 is a plan view showing a structure of a microstrip antenna according to a third embodiment of the present invention.

FIG. 6 is a plan view showing a structure when a chip antenna is used for a capacitive coupling portion in the microstrip antenna of the present invention.

FIG. 7 is a plan view showing a structure in which a contraction separating section is provided in a first radiation electrode portion in the microstrip antenna of the present invention.

FIG. 8 is a plan view showing a structure of a conventional microstrip antenna.

9 is a sectional view taken along line BB in FIG.

FIG. 10 is a plan view showing the structure of a conventional microstrip antenna.

11 is a sectional view taken along line CC in FIG.

[Explanation of symbols]

 1, 30, 40 Microstrip antenna 11 Substrate 12 First radiation electrode 13, 14, 33, 43, 44 Second radiation electrode 15 Ground electrode 16 Feeding hole 17 Through hole 18a, 18b, 18c, 18d Capacitive coupling unit 21 , 22 First comb-shaped electrode 23, 24 Second comb-shaped electrode 38 Chip-type capacitor

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-357702 (JP, A) JP-A-8-316726 (JP, A) JP-A-7-38328 (JP, A) JP-A-2- 130005 (JP, A) JP-A-64-4101 (JP, A) JP-A-63-169103 (JP, A) JP-A-59-16402 (JP, A) JP-A-8-316726 (JP, A) JP-B-60-36641 (JP, B2) U.S. Pat. No. 4,069,483 (US, A) U.S. Pat. No. 4,370,657 (US, A) International Publication No. 96/34426 (WO, A1) (58) Field surveyed (Int.Cl. ⁷ , DB name) H01Q 13/08 H01Q 5/01

Claims (4)

(57) [Claims] 1. A two-parallel, spaced apart in the thickness direction.
A substrate composed of two main surfaces and four side surfaces connecting the main surfaces, a first radiation electrode formed on one principal surface of the substrate, and a peripheral portion of the first radiation electrode. , The first
Formed perpendicular to each other with reference to the center point of the radiation electrode
At least two second radiating electrodes, a ground electrode formed on the other main surface of the substrate, and a portion corresponding to the first radiating electrode of the substrate between the two main surfaces of the substrate. A power supply through-hole, a grounding through-hole formed at a location of the substrate corresponding to the second radiation electrode,
A microstrip antenna, comprising: a radiation electrode and at least two capacitive coupling portions for capacitively coupling the second radiation electrode. 2. A two-parallel unit which is separated from each other in a thickness direction.
One main surface and four side surfaces connecting the main surfaces.
Substrate and a first radiation formed on one main surface of the substrate
An electrode, and the first radiation electrode on the periphery of the first radiation electrode.
At least one substantially L-shaped member formed with an interval
A second radiation electrode and a ground formed on the other main surface of the substrate
Between the electrode and the two main surfaces of the substrate,
Feeding through hole formed at a location corresponding to one radiation electrode
Formed at a position corresponding to the second radiation electrode on the substrate
Ground through hole, the first radiating electrode, and the second
At least two capacitive couplings for capacitively coupling the
And a joining part . 3. A first comb-shaped electrode formed to protrude from the first radiation electrode in the direction of the second radiation electrode, and a capacitive coupling portion extending in a direction from the second radiation electrode to the first radiation electrode. 3. The microstrip antenna according to claim 1, wherein the protruding second comb-shaped electrode intersects with each other. 4. The microstrip antenna according to claim 1, wherein the capacitive coupling section is formed of a chip-type capacitor.