JP2000049527A - Microstrip antenna and its resonance frequency adjustment method - Google Patents

Abstract

(57) [Problem] To obtain a microstrip antenna capable of adjusting a resonance frequency without changing impedance. SOLUTION: A strip-shaped additional electrode is connected to a rectangular radiating electrode, and the width and the number of the additional electrodes connected to two opposing sides are equal, and the ratio of the length is the distance from the side to the feeding point. Keep them equal. The frequency is adjusted by removing the same number of additional electrodes on the two sides facing each other.

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 a method for adjusting its resonance frequency.
The resonance frequency can be adjusted by the structure of the radiation electrode and its trimming.

[0002]

2. Description of the Related Art Microstrip antennas are used in various fields as antennas for navigation systems and the like. For example, as an antenna for receiving a circularly polarized signal transmitted from a communication satellite, there is an antenna having a rectangular electrode as a radiation electrode and having a feeding point at a position deviated from the center on the diagonal line.

FIG. 2 is a plan view of such a conventional microstrip antenna. The radiation electrode 22 is formed by printing and baking a conductor such as silver on the surface of the dielectric substrate 20. The resonance frequency of this antenna depends on the dimensions of the radiation electrode.
This is a unique frequency based on a3 and b3. Also, the impedance of the feeding point is a1: a2, b1: between the feeding point and the edge of the radiation electrode.
Determined by the ratio of b2.

[0004]

The dielectric substrate is obtained by firing ceramics, but the resonance frequency varies due to the variation of the dielectric constant. Therefore, it is necessary to adjust the resonance frequency by trimming the radiation electrode. However, when the electrodes are shaved, the above-mentioned a1: a2 and b1: b2 also change, and impedance matching cannot be obtained.

[0005] The present invention provides a microstrip antenna capable of adjusting the resonance frequency without changing the impedance.

[0006]

The present invention solves the above-mentioned problems by adding a strip-shaped electrode to the radiation electrode and trimming the electrode.

That is, in a microstrip antenna having a rectangular radiation electrode on the surface of a rectangular dielectric substrate, two opposite sides of the radiation electrode correspond to the ratio of the distance from those sides to the feeding point of the radiation electrode. It is characterized by having the same number of strip-shaped additional electrodes extending to the end face side of the dielectric substrate and having the same length and the same width.

Further, the present invention is characterized in that the resonance frequency is adjusted by cutting these strip-shaped additional electrodes.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A radiation electrode with an additional electrode is formed so as to have a frequency lower than a desired frequency,
By cutting and removing the same number of strip-shaped additional electrodes on each of the opposing sides, the resonance frequency shifts to a higher one. Since the same number of additional electrodes are removed, the resonance frequency can be adjusted without changing the area ratio of the electrodes on both sides of the feed point and without changing the impedance.

[0010]

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

FIG. 1 is a plan view showing an embodiment of the present invention. Rectangular radiation electrode on the surface of the ceramic dielectric substrate 10
12 is formed by printing and baking a conductive paste such as silver. The feed point 13 is provided on a diagonal line of the radiation electrode that is offset from the center, and the distances from the feed point 13 to the edge of the radiation electrode are a1, a2, b1, and b2, respectively. This a1: a
2. The impedance of the feeding point is determined by b1, b2 as in the conventional example.

The microstrip antenna according to the present invention has strip-shaped additional electrodes 14, 15, 17, and 18 connected to the radiation electrode 12 and extending therefrom toward the end face of the dielectric substrate. Length X1 of additional electrode 14 and length X2 of additional electrode 15
Are set so that X1: X2 = a1: a2, and the widths are made equal. In this example, five additional electrodes are provided.

The lengths of the additional electrodes 17 and 18 are also set such that Y1: Y2 = b1: b2, and the widths are equal and the same number.
The antenna element including the radiation electrode 12 and the additional electrodes 14, 15, 17, 18 is set to have a resonance frequency slightly lower than a predetermined frequency.

In adjusting the resonance frequency of the antenna, trimming is performed in such a direction that the frequency is gradually increased while at least one of the additional electrodes 14, 15 and 17, 18 is cut and removed one by one. Radiation electrode 12 and additional electrodes 14, 15, 1
This is because the combined area of 7 and 18 is reduced, and the effective dimensions are reduced.

For example, the additional electrode 14a of the additional electrode 14
When the additional electrode 15a of the additional electrode 15 is removed by cutting, the resonance frequency slightly increases. Since the additional electrode 14a and the additional electrode 15a have the same width and have a relationship of X1: X2 = a1: a2, the effective dimensional ratio of the radiation electrode to the feeding point still remains a1: a2. Therefore, no change occurs in the impedance of the feeding point.

By removing the same number of additional electrodes 17 and 18, the resonance frequency can be adjusted while maintaining the impedance. Trimming is performed while measuring, and when the desired frequency is reached, the trimming ends. The length and number of the additional electrodes may be set in consideration of the frequency that needs to be adjusted.

[0017]

According to the present invention, since the size of the additional electrode is set as described above and is cut and removed, the resonance frequency can be adjusted without changing the impedance. Therefore, the man-hour for trimming, which has been troublesome up to now, can be greatly reduced.

Further, since the strip-shaped additional electrode is cut, the workability is good, and there is an advantage that the amount of trimming can be grasped by the number of additional electrodes. ,

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a plan view showing a conventional microstrip antenna.

[Explanation of symbols]

 10, 20: Dielectric substrate 12, 22: Radiation electrode 14, 15, 17, 18: Additional electrode

Claims (4)

[Claims] 1. A microstrip antenna having a rectangular radiation electrode on a surface of a rectangular dielectric substrate,
On two opposite sides of the radiation electrode, the width is the same length according to the ratio of the distance from those sides to the feed point of the radiation electrode,
A microstrip antenna comprising the same number of strip-shaped additional electrodes extending to the end face side of a dielectric substrate. 2. A microstrip antenna having a rectangular radiation electrode on a surface of a rectangular dielectric substrate,
One of the two opposite sides of the radiating electrode has the same length and width according to the ratio of the distance from those sides to the feed point of the radiating electrode, and the same number of strips extending to the end face side of the dielectric substrate And the same width on the other two opposing sides of the radiating electrode, with the length corresponding to the ratio of the distance from those sides to the feed point of the radiating electrode, and on the end face side of the dielectric substrate. A microstrip antenna comprising the same number of extending strip-shaped additional electrodes. 3. A method for adjusting a resonance frequency of a microstrip antenna having a rectangular dielectric electrode on a surface of a rectangular dielectric substrate, wherein two opposing sides of the radiation electrode are connected to a feed point of the radiation electrode from those sides. A micro-characteristic is characterized in that the same number of strip-shaped additional electrodes extending to the end face side of the dielectric substrate are formed with the same length and the same width according to the distance ratio, and the same number of these additional electrodes are cut. A method for adjusting the resonance frequency of a strip antenna. 4. A method for adjusting the resonance frequency of a microstrip antenna having a rectangular radiation electrode on the surface of a rectangular dielectric substrate, wherein two opposite sides of the radiation electrode are provided with feed points of the radiation electrode from those sides. The same width and the same width and the same number of strip-shaped additional electrodes extending to the end face side of the dielectric substrate are formed on the other two opposite sides of the radiation electrode. The same number of strip-shaped additional electrodes extending to the end face side of the dielectric substrate are formed with the same length and the same width according to the ratio of the distance from the side to the feed point of the radiation electrode. A method for adjusting the resonance frequency of a microstrip antenna, comprising cutting the same number of additional electrodes on the side.