JPH0936650A - Microstrip antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve moldability, to attain stabilization without dispersing a dielectric constant and to improve mass-productivity by forming a dielectric so as to contain a PPS and a TiO2 and by injection molding. SOLUTION: A patch 1 is formed in a radial conductor consisting of metallic foil of copper, etc., of short size. A dielectric substrate 2 of same short size is constituted in such a way that the injection molding of the PPS(polyphenylene sulfide) is applied to a base material 2a by using the TiO2 , and a mixing material 2b is scattered nearly uniformaly in the base material 2a. Also, the patch 1 is adhered on the surface one side of the dielectric substrate 2, and a ground 103 consisting of the metallic foil of copper, etc., is adhered on the surface on the other side. A coaxial probe 105 is provided on a ground 103 side, and the core 105a of the probe is provided so as to pierce through the dielectric substrate 2 and the ground 103 in a state separated electrically from the ground 103, and to be connected electrically to a feed point 3 representing a prescribed position on the patch 1.

Description

Detailed Description of the Invention

[0001]

[0001]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microstrip antenna used for mobile communication and portable radio.

[0003]

[0002]

[0004]

2. Description of the Related Art Conventionally, there is a microstrip antenna shown in FIG. 2 as a high frequency antenna used for mobile communication and portable radio.

FIG. 2 is a schematic sectional view of a conventional microstrip antenna.

In FIG. 2, a conventional microstrip antenna has a dielectric substrate 101 in which a patch 102 made of a thin metal conductor plate and a ground 103 have a constant dielectric constant.
The coaxial probe 105 is arranged on the side of the ground 103 by being adhered to both surfaces thereof. The ground 103 is electrically connected to the covered wire 105b of the coaxial probe 105, and the covered wire 105b is grounded to the earth 104.
Further, the core wire 105a of the coaxial probe 105 is the dielectric substrate 1
It is electrically connected to the patch 102 at a feeding point 106 which is a predetermined position of the patch 102 by penetrating 01.

[0007]

Since the conventional microstrip antenna is constructed as described above, when a radio wave arrives at the microstrip antenna, the end of the patch 102 and the ground 1 are detected.
Since a domain wall between 03 and 03 functions as a resonator, an eigenmode is excited in the dielectric substrate 101 and the coaxial probe 10
It is supplied to a receiving device (not shown) connected to 5.

[0008]

Here, the eigenmode consists of the fundamental mode and its higher-order modes, and the frequency of the fundamental mode is the dielectric substrate 1.
Patch 10 in the direction of reception of linearly polarized waves with a dielectric constant (ε) of 01
Since the value is determined by the length (d) of 2, the dielectric constant (ε) of the dielectric substrate 101 and the patch 1 are required to stabilize the frequency received by the microstrip antenna.
It is necessary that the length (d) of 02 is always stable.

[0009]

If the dielectric constant (ε) of the dielectric substrate 101 is high when receiving the same frequency, the patch 10
Since the length (d) of 2 can be set small, the antenna becomes small, and the lower the dielectric loss tangent (tan δ) of the dielectric substrate 101, the higher the resonance frequency Q of the reception frequency, and the better the reception performance, which is desirable as a microstrip antenna. . Therefore, the dielectric substrate of the conventional microstrip antenna is constructed by using a sintered ceramic substrate that satisfies these conditions.

[0010]

[0006] However, a sintered ceramic substrate is formed by heat treatment at a high temperature for a long time in a firing furnace to make it porcelain, and its size shrinks by 15 to 30% as compared with that before firing.
For this reason, it is difficult to control the temperature to obtain the required dimensions, and it takes a long time for firing, so that the cost is high.

Further, since the value of the dielectric constant of the sintered ceramic substrate is determined by the temperature applied during firing, it is necessary to make the temperature in the firing furnace uniform in order to generate the dielectric constant without variation. Since it is difficult to produce a large amount of ceramic substrates and temperature control is difficult, mass production is poor and cost is high.

[0012]

In recent years, the diversification of information has advanced, and GPS (Glob) using satellite radio waves is used as a communication means used in automobiles and the like.
The demand for the Al Positioning System is increasing. A small microstrip antenna is suitable for such communication means, but it is difficult to meet various demands in terms of mass productivity and cost in a conventional microstrip antenna using a ceramic substrate as a dielectric substrate. there were.

[0013]

[0008]

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and provides a microstrip antenna having a dielectric substrate having good moldability, stable dielectric constant without variation, and good mass productivity. It is provided.

[0015]

[0009]

[0016]

According to the first aspect of the present invention,
In a microstrip antenna in which a flat plate-shaped dielectric is sandwiched between a radiating conductor and a grounding conductor, and a feeding line for supplying electric power is attached to the feeding point on the radiating conductor, the dielectric contains PPS (polyphenylene sulfide) and TiO ₂ and is injection molded. The microstrip antenna is characterized by being formed by.

[0017]

[0010]

[0018]

The present invention is constructed as described above.
According to the invention described above, a base material having a good moldability and a low dielectric loss tangent is mixed with a mixture material having a high dielectric constant and a low dielectric loss tangent at a predetermined mixing ratio, and the dielectric substrate of a microstrip antenna is injection-molded. As a result, the permittivity does not vary, the receiving performance is stable, the cost is low, and the mass productivity is good.

[0019]

[0011]

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. 1. The same parts as those of the conventional device described with reference to FIG. 2 are designated by the same reference numerals.

FIG. 1 is a schematic sectional view of a microstrip antenna according to the present invention. In FIG. 1, reference numeral 1 denotes a patch having a rectangular size of 27 mm × 26 mm and a thickness of several tens μ.
m is a radiation conductor made of a metal foil such as copper. Reference numeral 2 is a dielectric substrate having a rectangular size of 30 mm × 30 mm and a thickness of several mm. The dielectric substrate 2 is a base material 2a described later.
PPS (polyphenylene sulfide) to the mixed material 2
b is injection-molded by using TiO ₂ , and the mixed material 2b is dispersed in the base material 2 almost uniformly.

[0022]

The patch 1 is adhered to one surface of the dielectric substrate 2, and the ground 103 made of a metal metal foil such as copper is adhered to the other surface of the dielectric substrate 2. The coaxial probe 105 is provided on the side of the ground 103, and the core wire 105 a of the probe penetrates the dielectric substrate 2 and the ground 103 in a state of being electrically isolated from the ground 103 and supplies power to indicate a predetermined position on the patch 1. It is provided so as to be electrically connected to the point 3. The covered wire 105b is electrically connected to the ground 103 and grounded to the ground 104.

[0023]

Now, the process of forming the dielectric substrate 2 will be described.

First, PPS (polyphenylene sulfide), which is the base material of the dielectric substrate, is mixed with TiO 2.
Mix ₂ in the given weight ratio. Here, TiO ₂ has a high dielectric constant and a low dielectric loss tangent, which are characteristics required for a dielectric substrate of a microstrip antenna. Also PPS
(Polyphenylene sulfide) is a synthetic resin, has a low dielectric loss tangent, can be easily and uniformly mixed with TiO _2, and has good moldability when used in injection molding.

Next, a predetermined amount of glass fiber necessary for pelletization is mixed with the mixed material, heated at a predetermined temperature to be softened and kneaded, and then a pellet which is a molding material is formed using a biaxial extruder. Then, it is molded by an injection molding machine to form the dielectric substrate 2.

[0026]

Here, the dielectric constant of the dielectric is PPS which is the base material.
TiO mixed with (polyphenylene sulfide)
It is set by ₂ weight ratio, 50 weight ratio of TiO ₂
If the dielectric constant ε is changed from about 8% to about 75% by weight,
A value of about 16 is obtained.

When the dielectric constant ε of the dielectric substrate 2 in the microstrip antenna of FIG. 1 is set to 15.0, its resonance frequency becomes 1575.42 MHz, and it can be easily applied to communication means such as GPS using satellite radio waves. can do.

[0028]

In this embodiment, the case of reception has been described, but the present invention may be used in the case of transmission.

[0029]

[0016]

[0030]

Since the present invention is constituted as described above, PPS (polyphenylene sulfide), which is a base material having good moldability and low dielectric loss tangent, is mixed with TiO ₂ which has a high dielectric constant and low dielectric loss tangent. Are mixed at a predetermined mixing ratio, and the dielectric substrate of the microstrip antenna is formed by injection molding, so that the dielectric constant does not vary and the receiving performance is stable, and the cost is low and the mass productivity is good.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a microstrip antenna according to the present invention.

FIG. 2 is a schematic sectional view of a conventional microstrip antenna.

[Explanation of symbols]

 101 ... Dielectric substrate 102 ... Patch 103 ... Ground 104 ... Ground 105 ... Coaxial probe 105 105a ... Core wire 105b ... Coated wire 105b 106 ...・ Feeding point 1 ・ ・ ・ ・ Patch 2 ・ ・ ・ ・ ・ ・ ・ ・ Dielectric substrate 2a ・ ・ ・ Substrate 2b ・ ・ ・ Mixed material 3 ・ ・ ・ ・ Feeding point

Claims (1)

[Claims] 1. A microstrip antenna in which a flat plate-shaped dielectric is sandwiched between a radiation conductor and a grounding conductor, and a feeding line for supplying electric power is attached to a feeding point on the radiation conductor, wherein the dielectric is PPS (polyphenylene sulfide). )
A microstrip antenna characterized by including TiO ₂ and TiO ₂ and being formed by injection molding.