JP2002111315A - Dielectric duplexer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease interference between resonators for the improvement of isolation. SOLUTION: On the short-circuited end surface 15 of a reception side dielectric filter RX, which has on its end a resonator 14 for attenuation pole formation, a slit 16, where a dielectric is exposed, is formed between the dielectric filter RX and the resonator for attenuation pole formation. Thus the isolation characteristic of transmission/reception within a transmission side pass-band is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a dielectric duplexer, and more particularly, to a duplexer capable of reducing interference and improving isolation characteristics.

[0002]

2. Description of the Related Art Dielectric filters and duplexers are widely used in terminal equipment of mobile communication equipment. In addition to connecting individual coaxial TEM resonators, a plurality of resonators are integrated with a dielectric block. The use of devices configured to reduce the size is increasing. As shown in FIGS. 4 and 5, a single dielectric block 40 includes a transmission filter T _X and a reception filter R _X
Are also in practical use.

In order to improve the band-pass characteristics by increasing the amount of attenuation outside the band, a resonator for forming an attenuation pole may be added. The resonators 43 and 44 shown in FIGS. And forms an attenuation pole on the high band side or the low band side of the pass band.

In a dielectric duplexer, sufficient isolation between transmission and reception and between antenna and reception must be obtained. If there is any signal leakage or interference between the elements, the isolation characteristics deteriorate. In a duplexer to which a resonator is added to form an attenuation pole as shown in FIGS. 4 and 5, as shown in FIG. The smaller the amount, the more the isolation characteristic deteriorates.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the isolation characteristics by making it possible to secure the attenuation between transmission and reception in a dielectric duplexer. Without increasing the number of elements and the number of parts,
An object of the present invention is to provide a duplexer capable of improving isolation characteristics.

[0006]

The present invention solves the above-mentioned problems by improving the shape of a conductor film formed on a short-circuit end face.

That is, the dielectric block has a plurality of parallel through holes, and an inner conductor is formed on the surface of the through hole, an outer conductor is formed on a surface where the through hole does not open, and a short-circuit conductor is formed on one of the surfaces where the through hole opens. In a dielectric duplexer including two dielectric filters each including a plurality of resonators, a resonator for forming an attenuation pole is added at least outside the resonator on the receiving side of the resonator on the side opposite to the antenna terminal. In addition, a slit is formed in the conductor film on the short-circuit end surface so as to expose a dielectric that crosses between the resonator at the output end and the resonator for forming the attenuation pole.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is applied to a duplexer, in which a resonator for forming an attenuation pole is added to at least a filter on a receiving side, and is formed between an end resonator and a resonator for forming an attenuation pole. A desired effect can be obtained by forming a slit for exposing the dielectric in the conductor film on the short-circuit end face.

The slit is formed so as to cross between the resonators, but the shape and size thereof can be arbitrarily changed.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 5 is a plan view showing a basic structure of a short-circuit end face of a dielectric duplexer to which the present invention is applied.
As shown in FIG. 4, size to form a receiving filter R _X of the transmit filter T _X and 3 elements of the rectangular parallelepiped dielectric 3 element of dielectric constant of about 91 at 21.3mm × 8.75mm × 3.8mm. At both ends, resonators 43 and 44 for forming an attenuation pole are arranged.

A conductor film 45 is formed on the short-circuit end face. In this example, input / output (transmission and reception) terminals 47 and 48 and an antenna terminal 49 are provided.
Is also formed on the short-circuit end face while being insulated from the conductor film 45. The resonators 43 and 44 forming the attenuation pole are arranged outside the input / output terminals.

The pass band on the transmitting side of the dielectric duplexer thus configured is 824 MHz to 849 MHz. FIG. 3 shows the isolation characteristics of the dielectric duplexer having the structure of FIG. The solid line is the attenuation indicating the isolation characteristic between the antenna and the reception, and the broken line is the attenuation indicating the isolation characteristic between the transmission and the reception.

FIG. 1 is a plan view showing an embodiment of the present invention.
The dimensions and the arrangement of the resonators are the same as described above. In this example, the slit 16 in the conductive film 15 is formed between the resonator 14 for the attenuation pole formed with the receiving side filter R _X, part of the slit 16 is exposed dielectric not formed conductive film I have. In this example, the slit 16 traverses vertically between the filter _RX and the resonator 14, is bent, extends toward the resonator 14, and has a shape surrounding a part thereof.

FIG. 2 shows the isolation characteristics of the dielectric duplexer shown in FIG. The broken line is the same as that shown in FIG. 3 of the related art, and the solid line shows that the attenuation amount has been increased by forming the slit.

The position and shape of the slit formed in the conductor film can be arbitrarily changed.

[0016]

According to the present invention, the isolation characteristic can be improved by increasing the attenuation by merely forming a slit in the conductor film at the short-circuit end face. It is not necessary to change the shape and the number of elements of the dielectric resonator, and a small and inexpensive dielectric duplexer can be obtained without adding any special parts.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram of characteristics of a dielectric duplexer according to the present invention.

FIG. 3 is an explanatory diagram of characteristics of a conventional dielectric duplexer.

FIG. 4 is a perspective view showing an example of a general dielectric duplexer.

FIG. 5 is a bottom view of an example of a conventional dielectric duplexer.

[Explanation of symbols]

T _X: transmitting filter R _X: reception filter 14: resonance for attenuation pole formed 15: conductive film 16: slit

Claims (2)

[Claims] 1. A dielectric block having a plurality of parallel through holes, wherein an inner conductor is formed on a surface of the through hole, an outer conductor is formed on a surface where the through hole does not open, and a short-circuit conductor is formed on one of a surface where the through hole opens. In a dielectric duplexer including two dielectric filters each including a plurality of resonators, a resonator for forming an attenuation pole is added at least outside the resonator on the receiving side of the resonator on the side opposite to the antenna terminal. , On the conductor film on the short-circuit end face,
A dielectric duplexer, wherein a slit exposing a dielectric crossing between a resonator at an output end and a resonator for forming an attenuation pole is formed. 2. A dielectric block comprising a plurality of parallel through holes, wherein an inner conductor is formed on a surface of the through hole, an outer conductor is formed on a surface where the through hole does not open, and a short-circuit conductor is formed on one of a surface where the through hole opens. In a dielectric duplexer including two dielectric filters each including a plurality of resonators, a resonator for forming an attenuation pole is added at least outside a receiving side of a resonator opposite to an antenna terminal, and a short-circuit end face is provided. Wherein a slit is formed in the conductive film to expose a dielectric surrounding a part of the resonator for forming the attenuation pole on the receiving filter side.