JPH04121125U - Ladder type electric filter - Google Patents

Abstract

(57) [Summary] [Purpose] To realize a thinner and smaller ladder-type electric filter. [Structure] The series resonators 5a and 5b are shaped like strips and their longitudinal vibration mode is used, and the parallel resonators 6a and 6b use the contour vibration mode as before. Series resonators 5a and 5b and parallel resonators 6a and 6b were separately stacked in the separated storage gap 3a and storage gap 3b, respectively. As a result, the number of laminated layers in the thickness direction is halved compared to the conventional configuration. Moreover, by reducing the area of the series resonators 5a and 5b by utilizing the longitudinal vibration mode, the installation area can be prevented from increasing.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention can be used in filter circuits of wireless communication devices such as portable mobile radios and car phones. It is used and mounted on a printed circuit board to construct the required filter circuit. Ladder type in which a series resonator and a parallel resonator forming a phase filter circuit are housed in a case. Regarding electric filters.

0002

[Conventional technology]

A ladder-type electric filter connects one electrode of a series resonator to the input side, and connects one electrode of a parallel resonator to the input side. Connect the side electrode to the ground side, and then connect the other side electrode of the series resonator and the other side of the parallel resonator. It is configured by connecting the electrode to the output side. And as this kind of ladder type electric filter , as a square of approximately 5 mm on a side, to operate at a center frequency of 455 KHz. Those using series resonators and parallel resonators using contour vibration mode, or diameter A series resonator and a parallel resonator that use a radial vibration mode as a circle with a diameter of approximately 5 mm. It is known to use

0003

[Problem that the idea aims to solve]

In recent years, wireless communication devices have become lighter and smaller, and with this, filter circuits There is a strong desire for the ladder-type filter used to be thinner. by the way, Conventional filters using resonators of about 5 mm have a large total height including the case. Therefore, it was impossible to hope for a thinner product. The purpose of this invention is to provide a ladder-type electric filter that can be made smaller and thinner. It is something.

0004

[Means to solve the problem]

The present invention divides the case into front and rear parts, and installs a longitudinal vibration motor into the storage space on one side. The rectangular series resonators are stacked vertically, and the contour is placed in the storage space on the other side. It is characterized by vertically stacking square parallel resonators that use vibration modes. It is something to do.

[0005]

[Effect]

The rectangular series resonator allows the main resonant frequency of the longitudinal vibration mode to be adjusted around the center of the filter. Adjust to the wave number. On the other hand, the parallel resonator maintains the anti-resonance frequency of the contour vibration mode as before. Adjust to the center frequency of the filter. This allows the series resonator and parallel resonator to The required filter circuit is configured.

[0006]

【Example】

A ladder-type electric filter F according to the present invention will be explained according to FIGS. 1 to 5. In Figures 1 and 2, 1 is a synthetic resin material with openings 2a and 2b formed on both sides. The case 1 has a storage space formed by a partition wall 4. 3a and 3b are partitioned.

[0007] As shown in FIG. 2, the storage space 3a has a rectangular shape that is long in the width direction and short in the front and back direction. As shown in FIGS. 4 and 5, a rectangular series resonator is installed in the storage space 3a. 5a and 5b are arranged in a layered manner. Further, the storage space 3b has a square shape. , square-shaped parallel resonators 6a and 6b are arranged in a stacked manner. Here, series resonator 5 a, 5b are connected in series to reduce the capacitance with respect to the parallel resonators 6a, 6b. The resonators 5a and 5b are made thick, the parallel resonators 6a and 6b are made thin, and the The parallel resonators 6a and 6b are made into a square shape using the contour vibration mode as described later. , the electrode area is increased. In addition, the series resonators 5a, Achieve the required capacitance ratio by using the electrode on one side of 5b as a partial electrode. You can do it like this.

[0008] In the above configuration, the series resonators 5a and 5b have a width of 1.5 mm, a length of 3.8 mm, The shape is 0.50 mm thick, and the parallel resonators 6a and 6b are 4.65 mm in length and width, and the thickness is 0.32 mm. The shape is mm. In addition, case 1 that accommodates these has a length of 8.5 m in the front and back direction. m, horizontal width 5.5 mm, and thickness 2.5 mm.

[0009] The lower series resonator 5a is located within the housing gap 3a, as shown in FIGS. 1 and 4. An input terminal board 7 is arranged between the bottom electrode and the inner surface of the case 1 with a buffer plate 15 interposed therebetween. The connecting leg 7f projects outward from the opening surface 2a. Also, the series resonator 5 The storage spaces 3a and 3b are crossed between a and 5b through the insertion hole 4a of the partition wall 4. A connecting end 9e whose connecting surfaces are the upper and lower surfaces of the conductive plate 9 inserted through the The inner surface electrodes of the column resonators 5a and 5b are connected to each other. The connecting end 9e has an edge It is constructed by folding it in an overlapping manner. Furthermore, the series resonator 5b and the cage An output terminal plate 8 is disposed between the inner surface of the base 1 and the connecting leg 8f of the output terminal plate 8 is connected to the opening surface 2. It protrudes outward from a. This output terminal plate 8 penetrates through the partition wall 4 into the storage space 3a. , 3b, thereby connecting the top electrode of the parallel resonator 6b and the series resonator 5. It is electrically connected to the upper surface electrode of b.

0010 Located within the storage gap 3b and between the lower parallel resonator 6a and the inner surface of the case 1. The conductive plate 9 is disposed with a buffer plate 16 interposed therebetween. Also, the upper parallel Between the pendulum 6b and the inner surface of the case 1, there is a space between the pendulum 6b and the inner surface of the case 1. An output terminal plate 8 is provided to connect to the electrodes of the series resonator 5b, and as described above, The upper surface electrode of the parallel resonator 6b and the upper surface electrode of the series resonator 5b are electrically connected. I'm doing it. Furthermore, a ground terminal is provided between the parallel resonator 6a and the parallel resonator 6b. A daughter plate 10 is arranged together with an intervening plate 17, and is connected to each inner surface electrode, and has a ground terminal. The connecting leg 10f of the plate 10 projects from the opening surface 2b. Each of the above-mentioned terminal plates 7, 8, 9 and 10, the electrodes of the series resonators 5a and 5b and the parallel resonators 6a and 6b, respectively. A pressure contact ridge 14 is formed in each case in order to ensure the connection with.

[0011] After installing each member in the case 1 in this way, the opening surfaces 2a and 2b are respectively shielded. Connecting legs 7f, 8f, 10f of terminal plates 7, 8 and terminal plate 10 are connected by plates 12, 12. The case is inserted and covered, and then filled with sealing material 13, 13 such as epoxy resin. The inside of space 1 is sealed in a liquid-tight manner. Then, connect the connecting legs 7f, 8f, 10f to the opening surface. 2a and 2b, and attach the end to the bottom edge of case 1 as shown in Figures 1 and 3. Extends to the department. Therefore, the ladder type electric filter F according to the present invention is assembled. Become.

0012 In this configuration, the series resonators 5a and 5b are shaped like strips, and the longitudinal direction of the series resonators 5a and 5b is The main resonant frequency of the longitudinal vibration mode in the direction is matched to the center frequency of the filter. and , the parallel resonators 6a and 6b pass the anti-resonant frequency of the contour vibration mode into the filter as before. The series resonators 5a, 5b and the parallel resonators 6a, 6b constitutes a required unit filter circuit.

[0013] In the configuration of this ladder-type electric filter F, the series resonators 5a and 5b have a rectangular shape. Therefore, its shape and dimensions are significantly smaller than that of a square, and furthermore, each straight line is The column resonators 5a, 5b and the parallel resonators 6a, 6b are separated by a partition wall 4 in the case 1. Since they are separated and laminated within the respective storage spaces 3a and 3b, the conventional structure The number of laminated sheets in the thickness direction is half that of the conventional one. For this reason, the thickness of case 1 is In addition, the series resonators 5a and 5b can have a longitudinal vibration mode. By using the board to reduce the area, the installation area can be prevented from expanding. Therefore Miniaturization is achieved.

[0014] This ladder type electric filter F has an input terminal plate 7, an output terminal plate 8 and a ground at the bottom. The terminal plate 10 is exposed, and therefore each conductive path formed on the desired printed circuit board is exposed. For example, by electrically connecting the exposed ends of the terminal board by soldering etc. We can construct the filter circuit shown in That is, each series resonator 5a, 5b is connected to an input terminal board. 7. Connect in series to the input/output terminals 20 and 21 via the output terminal board 8, and connect in parallel. The column resonators 6a and 6b are connected to the ground terminal 22 side through the ground terminal plate 10, and connect them in parallel. Therefore, filtering can be achieved by using multiple ladder-type electric filters F. A circuit will be constructed.

[0015]

[Effect of the idea]

As described above, in the present invention, the series resonators 5a and 5b are shaped like strips, and the length of the series resonators 5a and 5b is The horizontal vibration mode is used, and the parallel resonator uses the contour vibration mode as before. A storage space 3a and a storage space 3b, which are separated by a partition wall 4 within the space 1, are provided separately. Since it is a laminated structure, the number of laminated layers in the thickness direction is half that of the conventional structure. Moreover, the longitudinal vibration mode is utilized in the series resonators 5a and 5b to reduce the area. This prevents the installation area from increasing. For this reason, it is possible to use a ladder-type electric filter F. It is an excellent product that can be made thinner and more compact, contributing to the miniaturization of radio equipment, mobile phones, etc. It has a positive effect.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view of a ladder-type electric filter F of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG. 1;

FIG. 3 is a perspective view of the ladder-type electric filter F of the present invention.

FIG. 4 is an isolated perspective view of each mounting member.

[Fig. 5] Series resonators 5a, 5b and parallel resonators 6a, 6
It is a perspective view of b.

FIG. 6 is a filtering circuit diagram using a ladder-type electric filter F of the present invention.

[Explanation of sign]

F Ladder type electric filter 1 case 3a, 3b Storage gap 4 Partition wall 5a, 5b series resonator 6a, 6b parallel resonator 7,8,9,10 Terminal board

Claims (1)

[Scope of utility model registration request] 1. A ladder-type electric filter comprising a series resonator and a parallel resonator constituting a unit filtering circuit housed in a case, wherein the case is divided into front and rear parts, and a housing gap on one side is provided with: It is characterized by vertically stacking strip-shaped series resonators that use longitudinal vibration mode, and square-shaped parallel resonators that use contour vibration mode stacked vertically in the storage space on the other side. Ladder type electric filter.