JPH05283927A - Microstrip antenna - Google Patents

Abstract

PURPOSE:To facilitate the adjustment of frequency characteristic and to improve productivity by providing small projections and small slots on the edge of a radiation elements and making the adjustment of antenna resonance frequency while eliminating some of the radiation element conductor adjacent to the fine slots or small projections. CONSTITUTION:When power is applied from the back side to a power supply point 4 formed at the location deviated from the center 8 of a radiation element conductor 3 provided on a dielectric substrate 1 through pins, a microstrip antenna circuit consisting of the conductor 3, earth conductor 2, and a substrate 1 operates as a square microstrip antenna. A slot 7 which is formed at the center of the conductor 3 is provided at a location containing the center 8 so as to generate the circular polarized wave. A plurality of small projection 5 are provided on two edges 9 and 10 on the conductor 3. The small slot 6 is placed near the two edges 11 and 12 of the conductor 3. When removing two small projections 5, the capacitance component changes against two resonance modes to enhance the resonance frequency. The resonance frequency becomes low when removing a hatching section 13 of the small slot 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microstrip antenna used in the quasi-microwave or microwave band, and more particularly to a microstrip antenna whose resonance frequency can be easily adjusted.

[0002]

2. Description of the Related Art In recent years, wireless communication systems using frequencies in the quasi-microwave band or microwave band have been put into practical use, and microstrip antennas have been widely used as antennas for such communication systems. Came.
The microstrip antenna is thin, but its frequency characteristic is generally in a narrow band, and as a frequency adjusting method thereof, a method disclosed in Japanese Patent Laid-Open No. 3-80603 is known.

An example of a conventional microstrip antenna is shown in FIG. In FIG. 5, 14 is a dielectric substrate, 15 is a radiating element conductor, 16 is a minute protrusion formed on the peripheral portion of the radiating element conductor 15, 17 is the center of the radiating element conductor 15, 1
Reference numeral 8 is a feeding point.

A ground conductor (not shown) is formed on the back surface of the dielectric substrate 14, and a feeding point 18 is provided at a position radially displaced from the center 17 of the radiating element conductor 15 provided on the dielectric substrate 14. It is provided. A microwave signal is fed from the feeding point 18. The resonance frequency of the microstrip antenna can be adjusted by changing the radial length of the minute protrusions 16. When the length of the minute protrusion 16 is short, the resonance frequency of the microstrip antenna becomes high.

[0005]

However, in the case of the above-described conventional microstrip antenna, the change in the resonance frequency obtained by cutting the minute protrusions 16 is only the increase in the frequency, and the resonance frequency cannot be lowered. That is, since it is difficult to lengthen the minute protrusions 16 after forming the pattern of the minute protrusions 16 by etching, there is a problem that the resonance frequency cannot be adjusted to a low value after the pattern formation.

[0006]

In order to solve the above problems, the present invention provides a microstrip antenna in which a radiating element conductor and a ground conductor are provided with a dielectric substrate sandwiched between them. And a part of the radiating element conductor adjacent to the minute slot or the minute protrusion is removed, so that the resonance frequency of the antenna can be adjusted to be low or high.

[0007]

According to the above structure, the resonance frequency of the antenna can be adjusted to a high level by removing a part or all of the minute projections formed on the radiating element conductor, and at the same time, one of the radiating element conductors forming the minute slot can be obtained. The resonance frequency can be adjusted to be low by removing the part. That is,
By arranging the minute slot and the minute protrusion for the same resonance mode, by removing a part of the radiating element conductor adjacent to the minute protrusion or minute slot when adjusting the resonance frequency of the antenna, resonance occurs even after pattern formation by etching. It becomes possible to raise or lower the frequency.

[0008]

1 is a perspective view of an embodiment of the present invention. In FIG. 1, 1 is a dielectric substrate, 2 is a ground conductor formed on the back surface of the dielectric substrate 1, 3 is a substantially square radiation element conductor formed on the front surface of the dielectric substrate 1, and 4 is the radiation element. A feeding point 5 formed at a position slightly deviated from the center 8 of the conductor 3 is a minute projection formed so as to project outward from the radiation element conductor 3 at the edge of the radiation element conductor 3, and 6 is the minute projection. Micro slots formed in the edge of the radiating element conductor 3 at positions facing 6; 7 a slot formed in the central portion of the radiating element conductor 3;
Reference numeral 12 is an edge of the radiating element conductor 3. Radiating element conductor 3
Etc. are provided on the dielectric substrate 1 by an etching technique.

When a feeding point 4 formed at a position displaced from the center 8 of the radiating element conductor 3 is fed from the back by a pin or the like, the microstrip antenna circuit formed by the radiating element conductor 3, the other conductor 2 and the dielectric substrate 1 becomes Operates as a rectangular microstrip antenna. The slot 7 formed in the center of the radiating element conductor 3 is provided at a position including the center 8 in order to generate a circularly polarized wave, and the radiating element conductor is inclined by 45 ° with respect to the line connecting the center 8 and the feeding point 4. 3 is formed so as to have a longitudinal direction.

By forming the slot 7 in this way, when the resonance mode of the rectangular patch is degenerated, two orthogonal resonance modes can be excited with a phase difference of 90 °. A plurality of the minute projections 5 are provided on the two edges 9 and 10 of the radiating element conductor 3, and a plurality of the minute slots 6 are provided near the two edges 11 and 12 of the radiating element conductor 3. The minute protrusions 5 and the minute slots 6 are formed together with the radiating element conductor 3 by an etching technique. By removing two of the minute protrusions 5 provided on the two edges 9 and 10, it is possible to change the capacitance component for the two resonance modes and simultaneously increase the resonance frequency.

FIG. 2 is an enlarged view of the minute slot 6 portion. In the figure, the hatching portion 13 represents a slot forming portion that forms the minute slot 6 in a part of the radiating element conductor 3. By removing the hatching portions 13 of the two minute slots 6 provided near the edges 11 and 12,
The current distribution can be changed for the two resonance modes of the radiating element conductor 3, and the resonance frequency can be simultaneously lowered.

Here, the method of removing the hatching portion 13 of one minute projection 5 or one minute slot 6 is not preferable because the susceptance of the admittance from the feeding point 4 to the antenna side changes. Therefore, as described above, adjustment is performed with the two minute protrusions and the two minute slots.

Further, each of the edges 9 and 10 is provided with one large projection, and each of the edges 11 and 12 is also provided with one large slot. The sizes of these projections and slots are changed to change the frequency. However, an error is likely to occur in the length adjustment, and it becomes difficult to finely adjust the frequency.

Therefore, adjustment is performed by providing a plurality of minute projections 5 and minute slots 6 and removing a part (the hunting portion 13) of the radiating element conductor 3 adjacent to one minute slot 5 to adjust the frequency. Reproducibility and reliability are improved.

Since the individual sizes of the minute projections 5, the minute slots 6 and the like are small, the influence of directivity of the radio wave emitted from the radiating element conductor 3 is small. To remove a part of the radiating element conductor 3, the corresponding portion of the radiating element conductor 3 is cut with a cutter or the like, and heat is applied to the minute protrusions 5 or the hunting portion 13 with a soldering iron or the like to soften the adhesive on the back surface of the pattern. This can be easily realized, but the same effect can be obtained by simply cutting with a cutter to cut off electrical conduction.

FIG. 3 shows an experimental result when the antenna resonance frequency is adjusted in the embodiment of the present invention. The experiment was conducted in the 1.5 GHz band, the BT range was used as the dielectric substrate 1, and the radiating element conductor 3, the minute protrusions 5, and the minute slots 6 were copper clad laminates with a thickness of 1.6 mm, and radio waves in the far field were used. The frequency characteristic of the axial ratio in the main radiation direction of was measured. In this experiment, the edges 9, 10, 11, 12
11 minute projections 5 and 11 minute slots 6 were provided respectively. The axial ratio minimum frequency on the vertical axis of the graph of FIG. 3 changes in proportion to the change of the resonance frequency of the radiating element conductor 3.

As is apparent from FIG. 3, when the protrusion 5 is removed, the axial ratio minimum frequency gradually increases, and the minute slot 6
Part of the radiating element conductor 3 adjacent to (hatched portion 13)
, The axial ratio minimum frequency becomes gradually lower. or,
Through the experiment, the value of the axial ratio is 1.4 dB to 3.9 dB, and there is no large change, and it can be seen that the two resonance frequencies corresponding to the two resonance modes have the same change.

Various modifications can be made to the embodiment of the present invention described above. What is shown in FIGS. 4A, 4B, 4C, 4D and 4E is a radiating element conductor 3 according to another embodiment of the present invention.
The same reference numerals are given to portions corresponding to the first embodiment of the present invention shown in FIG. In FIGS. 4A and 4B, the arrangement of the minute protrusions 5 and the minute slots 6 is the first.
4 (c) shows a case where the radiating element conductor 3 is a circular patch. Both have the same effects as those of the first embodiment. Figure 4
(D) and (e) are examples in which the present invention is applied to a linearly polarized antenna, which is about 45 ° with respect to the direction of the excitation mode.
The minute protrusion 5 and the minute slot 6 are provided at the inclined position. In this case as well, only the plane of polarization is different.
The same effects and advantages as in the case of the above embodiment are obtained.

As described above, according to the embodiment of the present invention, the resonance frequency of the microstrip antenna can be adjusted by an easy method even after the patterning of the radiating element conductor 3 is performed by etching. Therefore, not only adjustment to a particularly high frequency but also adjustment to a low frequency can be easily performed.

Therefore, in the case of adjusting the frequency with respect to the change of the resonance frequency due to the variation of the board thickness, if the antenna characteristics are adjusted so that the design frequency is obtained in the case of the average board thickness, most of the boards can be used. On the other hand, it is not necessary to adjust the frequency, and the above-mentioned frequency adjustment operation can be performed as necessary only when the substrate thickness varies and the frequency characteristics shift up and down. can do. Incidentally, the above embodiment can be variously modified within a range not to lose the effect of the present invention,
The shape, size, number, etc. of the radiating element conductor 3, the minute protrusions 5, the minute slots 6, and the slots 7 may be appropriately selected as necessary.

[0021]

Since the present invention is constructed as described above,
Since the resonance frequency of the antenna can be freely adjusted to be high or low even after the radiating element conductor is formed, the degree of freedom in antenna design is increased and the frequency adjustment operation is easy and the productivity is excellent. A microstrip antenna can be provided.

[Brief description of drawings]

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

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is an operation explanatory diagram of the present invention.

FIG. 4 is a view for explaining various other embodiments of the present invention, showing various plane patterns of the radiating element conductor.

FIG. 5 is a plan view of a conventional example.

[Explanation of symbols]

 1 Dielectric Substrate 2 Ground Conductor 3 Radiating Element Conductor 5 Micro Protrusion 6 Micro Slot 13 Hatching Part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Chizo Ota 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka

Claims (1)

[Claims] 1. A microstrip antenna in which a radiating element conductor and a ground conductor are provided with a dielectric substrate sandwiched between the radiating element conductor, and minute protrusions and minute slots are provided at the edges of the radiating element conductor.
A microstrip antenna characterized in that the resonance frequency of the antenna can be adjusted to be low or high by removing a part of the radiating element conductor adjacent to the minute slot or the minute protrusion.