JPS6028441B2 - strip line filter - Google Patents

Description

[Detailed description of the invention] The present invention relates to a strip line filter.

An object of the present invention is to provide a strip line filter which has advantages such as simpler structure, easier handling, smaller size, and lower cost than conventional filters.

In the present invention, a first full surface electrode is provided on one main surface of a dielectric substrate, a second full surface electrode connected to this full surface electrode is provided on one side surface, and the second full surface electrode is provided on one side surface. are made to extend on the other main surface of the dielectric substrate, while on the other main surface of the dielectric substrate, one end of each is provided on the other main surface of the dielectric substrate at a distance such that they can be bonded to each other, and on the extending tip side of the second full surface electrode. This is a strip line filter in which a plurality of 1/skin length resonant electrodes whose sides are connected are arranged, and external extraction electrodes are connected to the first and final stage resonant electrodes.

The above objects and other objects and features of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

In the figure, 1 is a dielectric substrate, 2 is one main surface of the dielectric substrate 1, 3 is an entire surface electrode provided on one main surface 2, 4 is one side surface of the dielectric substrate 1, and 5 is a side surface 4 The entire surface electrode is provided on the surface and is integrally connected to the surface electrode 3.

6 is the other main surface of the dielectric substrate 1, 7 is a part of the entire surface electrode 3 extending to a part of the other main surface 6, 8 is the extended end side of the part 7 of the entire surface electrode 3, and 9a to 9e are Extended tip side 8
The passband width is determined by the distance between each electrode, with one end open and the other end short-circuited. 10a to 10b are external extraction electrodes, and input electrodes 10
a is connected to the resonant electrode 9a, and the output electrode 10b is connected to the resonant electrode 9a.

When the distance A between the input electrode 10a and one end of the resonance electrode 9a connected to the extended end 8 becomes large, the external Q (Qe
) is in the value of 4. Conversely, when the interval A becomes smaller, the external Q (Qe) becomes a larger value. In addition, the input electrode 10a
As the width B becomes narrower, the external Q (Qe) becomes a larger value.
Conversely, as the width B increases, the external Q (Qe) becomes a smaller value. The same applies to the output electrode 1ob. Therefore, the interval A and width B are determined so as to obtain the required external Q (Qe) value. The electrodes 3, 5, 7, 9a to 9e, 10a, 10b are
It is preferable that the electrode is formed by a printing method using paint made of an electrode material such as Ag, Cu, or Au. Of course, in order to improve the strength, it may be subjected to a dazzling treatment after printing.

The entire surface electrode 3 does not necessarily need to extend to a part of the other main surface 6.

For example, the entire surface electrode 3 may be provided only on the side surface 4, and one end side of the resonance electrodes 9a to 9e may be located on one side 11 of the dielectric substrate 1. However, from a production standpoint, printing misalignment may cause the resonance Length C and interval A of electrodes 9a to 9e
etc. may differ from predetermined values, so it is more practical to extend the entire surface electrode 3 to a part of the other main surface 6. In other words, the part 7 of the entire surface electrode 3, the resonance electrodes 9a to 9e, and the external extraction electrodes 10a, 1
If a printed pattern in which 0b is integrally formed is used, even if there is some misalignment of printing on the dielectric substrate 1, the above-mentioned dimensions, which have an important influence on the characteristics, will not be distorted. The outline is as above, and the design procedure will be explained next.
First, find the external Q (sphere).

Qe=gjukukuiyuinii f However, △f is the obijo width, &, & is the so-called g value, W
It is the center frequency.

The relationship between external Q (Qe) and interval A has a tendency as shown in FIG.

Therefore, the distance A is determined according to FIG. Note that the width B is set to a predetermined constant value as described later.
On the other hand, the coupling coefficient Kj·i+1 between the resonator of the jth stage (i=1, 2, 3, 4 in the embodiment) and the resonator of the j+1st stage is determined. Ki. i+1=f.

Nog. g11 coupling coefficient Ki・i+1 and inter-resonator distance Dx
(in the example, x=1, 2, 3, 4) has a direction as shown in FIG.

Therefore, the interval x is determined according to FIG. Resonant electrode 9
The lengths C and ~C5 of a~9e are 300 CI=C2=C3=C4:C5=f if we ignore the effects of other resonators and input/output fabrics.

・There will be 4 refs. However, it is not effective. However, in reality, the lengths C and C5 of the resonance electrodes 9a to 9e are determined as follows because they are influenced by other resonators and input/output devices. 300 C. =C5=(ra1△f.

)-4 ref300Cx=(chi1△fX). The relationship between the degree of frequency change Δfo due to the input/output terminals and the interval A tends to be as shown in FIG. 5.

Although there are effects from other resonators, they are practically negligible compared to the effects from the input and output terminals. Further, the relationship between the degree of frequency change △ due to the influence of other resonators and the average value of the inter-resonator distance DX-X+DX is as shown in FIG. Based on these trends, the resonant electrode 9
Determine the lengths C and C5 of a to 9e. Note that the resonant electrode 9a
The width E of ~9e, the width F of the part 7 of the entire surface electrode 3, the lengths G and H of the external extraction electrodes 10a and 1ob, etc. are set to predetermined constant values. For example, M with a center frequency of 100
For HZ, B = 0.5 side, E = 1.6 legs, F = 1
．． On the side, G = H = 4 skins. Also, the dimensions of the board are 29
A kite with ribs x IQ x 1.5 sails, approximately 100 pieces, was used. FIGS. 7 and 8 show an example of the characteristics of the filter produced in this manner. The center frequency fo is 100■MHZ, 0
．． & The original bandwidth is 18 MHz, the return loss is 2, the insertion loss is 0.7 dB at the center frequency, and the temperature characteristics are about 2 legs/°C. As is clear from the above embodiments, according to the present invention, it is possible to provide a strip line filter that is simple in structure, easy to handle, small in size, and inexpensive.

[Brief explanation of the drawing]

FIG. 1 is a plan view of one embodiment of the present invention, and FIG. 2 is a plan view of one embodiment of the invention.
The right side view, Fig. 3 is a diagram showing the relationship between the interval A and external Q (handling), Fig. 4 is a diagram showing the relationship between the inter-resonator distance Dx and the coupling coefficient Kj·i11, and Fig. 5 6 is a diagram showing the relationship between the interval A and the degree of frequency change △ etc. due to the input and output ends, and FIG. 7 is a selectivity characteristic curve diagram, and FIG. 8 is a diagram illustrating passband characteristics and reflection loss. 1 is a dielectric substrate, 3 and 5 are full-surface electrodes, 9a to 9e are resonance electrodes, and 10a and 10b are external extraction electrodes. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] 1 A first full surface electrode is provided on one main surface of the dielectric substrate, a second full surface electrode connected to this full surface electrode is provided on one side surface, and this second full surface electrode is connected to the dielectric substrate. The electrodes are connected to the other main surface of the dielectric substrate at intervals such that they can be bonded to each other, and are connected at one end to the extending tip side of the second full-surface electrode. A stripline filter in which a plurality of 1/4 wavelength resonant electrodes are arranged, and an external lead-out electrode is connected to the first and final stage resonant electrodes.