JPH0964613A - Strip line resonator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a strip line resonator having high non-load Q. SOLUTION: A ground conductor 3 is formed on both the main surfaces of two superposed dielectric substrates 2, a strip conductor 4 of which tip is opened from one end of the side faces of the substrates 2 to the other end is formed between both the substrates 2 and a capacitor 6 is loaded on the substrates 2 in parallel with the conductor 4. In the parallel connection method of the conductor 4 and the capacitor 6, both the conductor 4 and capacitor 6 are mutually connected by a via hole 7 formed in the interior of the substrate 2. One end of the conductor 4 is connected to a short-circuit electrode 5 formed on the side face of the substrate 2 and short-circuited to the conductor 3 and the capacitor 6 is directly short-circuited to the conductor 3 to constitute the strip line resonator 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stripline resonator used in a voltage controlled oscillator (VCO) or the like.

[0002]

2. Description of the Related Art As a conventional stripline resonator,
There is one shown in FIG. In FIG. 3, the stripline resonator 1 includes a dielectric substrate 2, and the dielectric substrate 2
Ground conductors 3 are formed on both main surfaces of the dielectric substrate 2, and strip conductors 4 are formed inside the dielectric substrate 2 with open ends extending from one end to the other end of the side surface of the dielectric substrate 2. One end of 4 is connected to the ground conductor 3 by a short-circuit electrode 5 at one end of the side surface of the dielectric substrate 2.

In the method of forming the strip line resonator 1, a conductive paste is printed on the main surfaces of a plurality of dielectric substrates 2 and baked to form a ground conductor 3 and a strip conductor 4, and the dielectric substrate 2 is stripped. It is obtained by bonding the conductors so as to sandwich them, applying a conductive paste to one end side of the side surface of the dielectric substrate 2 and baking it to form side surface electrodes to form short-circuit electrodes.

[0004]

However, in the above-described conventional stripline resonator, the strip conductor 4 is used.
The length must be uniquely determined by the frequency, and its length is as long as 1/4 wavelength. Therefore, it must be shaped for use in voltage-controlled oscillators for mobile communication devices that require miniaturization. Need to be smaller.

The loss of the strip line resonator is
The conductor loss of the strip conductor and the dielectric loss of the dielectric substrate are the main factors, and both the conductor loss and the dielectric loss increase in proportion to the length of the strip conductor. Had a problem that the unloaded Q was small.

Therefore, an object of the present invention is to provide a stripline resonator having a small size and a high unloaded Q.

[0007]

In order to achieve the above object, in a stripline resonator of the present invention, a dielectric substrate and inside the dielectric substrate are arranged from one end of the dielectric substrate to the other end. In a stripline resonator including an open strip conductor and ground conductors formed on both main surfaces of the dielectric substrate, a capacitor is connected in parallel to the strip conductor, and one end of the strip conductor and The capacitor is short-circuited to the ground conductor.

In the strip line resonator, the short-circuit end side of the strip conductor is a low characteristic impedance line, and the open end side is a high characteristic impedance line.
The low characteristic impedance line and the capacitor are connected in parallel, and one end of the low characteristic impedance line and the capacitor are short-circuited to a ground conductor, respectively.

As a result, when a capacitor is connected in parallel with the strip conductor, the strip conductor apparently becomes long, so that the strip conductor can be shortened, conductor loss and dielectric loss are reduced, and the no-load Q is improved. Further, the short-circuit end side of the strip conductor is a low characteristic impedance line, the open end side is a high characteristic impedance line, and by connecting the low characteristic impedance line and the capacitor in parallel, conductor loss and dielectric loss are further reduced, The unloaded Q is further improved and the shape is downsized.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION One embodiment of a stripline resonator according to the present invention will be described below with reference to FIG. In FIG. 1, reference numeral 2 is a dielectric substrate, ground conductors 3 are formed on both main surfaces of the two dielectric substrates 2 stacked, and the dielectric substrate 2 is sandwiched between the two dielectric substrates 2. A strip conductor 4 having an open end is formed from one end of the side surface to the other end, and a capacitor 6 is mounted on the dielectric substrate 2 so as to be connected in parallel with the strip conductor 4. The method of connecting the strip conductor 4 and the capacitor 6 in parallel is performed by the via hole 7 formed inside the dielectric substrate 2 as shown in FIG. At this time, the via hole 7
In this embodiment, as shown in FIG. 1, the dielectric substrate 2 in the vicinity of the contact portion between the via hole 7 and the ground conductor 3 is shaved to form the void portion 8 so that the ground conductor 3 and the ground conductor 3 are not short-circuited. One end of the strip conductor 4 is connected to the short-circuit electrode 5 formed on the side surface of the dielectric substrate 2 and short-circuited to the ground conductor 3, and the capacitor 6 is directly short-circuited to the ground conductor 3 to form the stripline resonator 10. ing.

Next, another embodiment of the stripline resonator of the present invention will be described with reference to FIG. In FIG. 2, reference numeral 2 is a dielectric substrate, ground conductors 3 are formed on both main surfaces of the two dielectric substrates 2 stacked, and the dielectric substrate 2 is sandwiched between the two dielectric substrates 2. The strip conductor 4 whose tip is open from one end of the side surface to the other end is a low characteristic impedance line 4a on the short-circuited end side and a high characteristic impedance line 4b on the open end side, and the line width of the low characteristic impedance line 4a is wide. , High characteristic impedance line 4
Lines b are formed with a narrow line width, and a capacitor 6 is mounted on the dielectric substrate 2 so as to be connected in parallel with the low characteristic impedance line 4a. The method of connecting the low characteristic impedance line 4a and the capacitor 6 in parallel is by connecting via holes 7 formed inside the dielectric substrate 2 as shown in FIG. At this time, in order to prevent the via hole 7 and the ground conductor 3 from being short-circuited, in the present embodiment, as shown in FIG. 2, the dielectric substrate 2 in the vicinity of the contact portion between the via hole 7 and the ground conductor 3 is shaved to form the void portion 8. It is a thing. One end of the low characteristic impedance line 4a is connected to the short-circuit electrode 5 formed on the side surface of the dielectric substrate 2 and short-circuited to the ground conductor 3, and the capacitor 6 is directly short-circuited to the ground conductor 3 so that the stripline resonator 20 is connected. I am configuring.

Although not specifically shown, the stripline resonators 10 and 20 having such a structure have, for example, a pattern which becomes the strip conductor by a conductive paste on one main surface of a thin dielectric substrate. Print,
On the other main surface, a pattern to be the ground conductor may be printed with a conductive paste and baked, and this dielectric substrate and another dielectric substrate may be bonded by sandwiching the previously formed strip conductor therebetween. it can.

The value of the unloaded Q of the stripline resonator of the present invention having the above-mentioned structure is, for example, 2.1 GHz.
In the frequency band of, the thickness of the dielectric substrate 2 is 0.5 m
As a result of performing a numerical analysis on the stripline resonators 10 and 20 of m, the unloaded Q of the stripline resonator 10 according to one embodiment of the present invention is 46, and the unloaded Q of the stripline resonator 20 according to another embodiment is not. The load Q is 53, and the value of the unloaded Q of the conventional stripline resonator 1 is 3
Compared with No. 2, an improvement of 44% in one embodiment and an unloaded Q of 65% in the other embodiment is recognized.

The method for preventing the short circuit between the via hole 7 and the ground conductor 3 is not limited to the method of the above embodiment, but the ground conductor 3
May not be formed around the via hole 7, or an overglaze may be formed around the via hole 7. Further, although the short-circuit electrode 5 is a short-circuit electrode by forming a side surface electrode on the short-circuit end side of the strip conductor 4 in the above-described two embodiments, a through-hole electrode (not shown) is provided inside the dielectric substrate 2 on the short-circuit end side. May be formed as a short circuit electrode.

[0015]

As described above, in the stripline resonator according to the present invention, by connecting the strip conductor and the capacitor in parallel, the strip conductor becomes long, so that the strip conductor can be shortened, resulting in a conductor loss and a dielectric loss. And the unloaded Q is improved. Further, the short-circuited end side of the strip conductor is a low characteristic impedance line, the open end side is a high characteristic impedance line, and by connecting the low characteristic impedance line and the capacitor in parallel, conductor loss,
The dielectric loss is further reduced, the unloaded Q is further improved, and the shape is downsized.

[Brief description of drawings]

FIG. 1 is a perspective view showing a structure of a stripline resonator according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a structure of a stripline resonator according to another embodiment of the present invention.

FIG. 3 is a perspective view showing a structure of a conventional stripline resonator.

[Explanation of symbols]

 2 Dielectric substrate 3 Ground conductor 4 Strip conductor 4a Low characteristic impedance line 4b High characteristic impedance line 6 Capacitor 10, 20 Strip line resonator

Claims (2)

[Claims] 1. A dielectric substrate, a strip conductor formed inside the dielectric substrate so as to open from one end to the other end of a side surface of the dielectric substrate, and formed on both main surfaces of the dielectric substrate. A stripline resonator comprising a ground conductor formed by connecting a capacitor to the strip conductor in parallel, and shorting one end of the strip conductor and the capacitor to the ground conductor. 2. The stripline resonator according to claim 1, wherein the short-circuit end side of the strip conductor is a low characteristic impedance line, the open end side is a high characteristic impedance line, and the low characteristic impedance line and a capacitor are connected in parallel. A stripline resonator, wherein one end of the low characteristic impedance line and the capacitor are short-circuited to a ground conductor, respectively.