JP2006352277A

JP2006352277A - Wideband dielectric filter

Info

Publication number: JP2006352277A
Application number: JP2005172950A
Authority: JP
Inventors: Yoshihiro Konishi; 良弘小西; Kenji Endo; 謙二遠藤
Original assignee: TDK Corp
Current assignee: TDK Corp
Priority date: 2005-06-13
Filing date: 2005-06-13
Publication date: 2006-12-28

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wideband dielectric filter having a specific band exceeding 20%. <P>SOLUTION: A dielectric filter having a wide passband is provided without waste by setting a resonator at an I/O portion to be coupled directly with the outside and coupling internal resonators such that the resonators operate as a coupling line (coupler). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、ＵＷＢ等広帯域を取り扱う誘電体帯域通過フィルタに関する。 The present invention relates to a dielectric bandpass filter that handles a wide band such as UWB.

従来、携帯電話やそれらの基地局等に使用されている高周波用帯域フィルタは通常該当する周波数の信号を通さない信号伝達回路上に共振器を設置して所望する周波数帯の信号を通過させる帯域通過フィルタを形成している。例えば該当する周波数に於いて信号を遮断する導波管中に当該周波数近くで共振する誘電体共振器を設置している。携帯電話等の移動端末に使用される超小型の誘電体フィルタにおいても複数の誘電体共振器をキャパシタ、又はインダクタを形成させた事によるそれだけでは信号を伝達しない結合線路上に配置して結合させ、入出力部においてもキャパシタ、インダクタ、或いは相互誘導によるインダクタを利用して外部と整合を得ている。 Conventionally, a high-frequency bandpass filter used in mobile phones and their base stations normally has a band in which a signal in a desired frequency band is passed by installing a resonator on a signal transmission circuit that does not pass a signal of the corresponding frequency. A pass filter is formed. For example, a dielectric resonator that resonates near the frequency is installed in a waveguide that blocks a signal at the corresponding frequency. Even in ultra-small dielectric filters used in mobile terminals such as mobile phones, a plurality of dielectric resonators are arranged on a coupling line that does not transmit signals by itself by forming capacitors or inductors. Also in the input / output section, matching with the outside is obtained by using a capacitor, an inductor, or an inductor by mutual induction.

以上のような従来の共振器及びこれによりフィルタを形成する場合の共振器の結合方法には、次のような問題点があった。 The conventional resonator as described above and the resonator coupling method in the case where the filter is formed thereby have the following problems.

従来の方式では帯域を広く設計しようとしても、その比帯域が３０％を超えるような帯域通過フィルタは外部との整合が取れない、共振器間の結合強度が得られない、無理矢理定数の大きな結合素子を適用しようとしても共振器と結合素子の整合が得られなくなる、等の限界があり、実際に広帯域のフィルタを得ることは不可能であった。 Even when trying to design a wide band with the conventional method, a band pass filter whose ratio band exceeds 30% cannot be matched with the outside, the coupling strength between resonators cannot be obtained, and a coupling with a large force constant Even if an element is applied, there is a limit that the matching between the resonator and the coupling element cannot be obtained, and it is impossible to actually obtain a broadband filter.

本発明の課題は、以上の点を鑑み、所望する周波数帯域で信号を伝達しない伝達回路を用いることなく、新しい構成により広帯域フィルタを得ることである。 In view of the above points, an object of the present invention is to obtain a broadband filter with a new configuration without using a transmission circuit that does not transmit a signal in a desired frequency band.

上述した課題を解決するため、本発明は、入出力部の共振器を外部と直接結合するように設定し、内部の共振器間の結合も共振器同士が結合線路（カプラ）として動作させる。 In order to solve the above-described problems, the present invention is set so that the resonator of the input / output unit is directly coupled to the outside, and the coupling between the internal resonators also operates as a coupled line (coupler).

上記構成によれば、従来実現し得なかった広帯域の誘電体通過フィルタを得ることができる。 According to the above configuration, it is possible to obtain a broadband dielectric pass filter that could not be realized conventionally.

即ち、図１に示したように、フィルタの一方の入出力には１／４波長先端短絡共振器が直接接続されている。更にこの共振器に並んでもう一つの１／４波長先端短絡共振器が平行且つ逆向きに配置され結合している。該もう一つの１／４波長先端短絡共振器はもう一方の入出力に直接接続されている。共振器の特性そのもので外部と整合され、且つ共振器同士の結合が得られているので無駄なく広い通過帯域を得ることができる。 That is, as shown in FIG. 1, a quarter wavelength tip short-circuit resonator is directly connected to one input / output of the filter. In addition to this resonator, another quarter-wavelength tip short-circuited resonator is arranged in parallel and in the opposite direction and coupled. The other quarter-wavelength tip short-circuited resonator is directly connected to the other input / output. Since the characteristics of the resonator itself are matched with the outside and coupling between the resonators is obtained, a wide passband can be obtained without waste.

以上説明した本発明の広帯域誘電体フィルタは次のような効果がある。
（ａ）入出力部や共振器の段間部部に通過帯域となる周波数の電気信号を遮断する構成を持たないので効率よく広帯域のフィルタを形成することができる。
（ｂ）従来のフィルタではその比帯域が２０％を超えることは不可能であったのに対し、５０％以上の比帯域を持つものであっても容易に作ることができる。 The broadband dielectric filter of the present invention described above has the following effects.
(A) Since the input / output part and the interstage part of the resonator do not have a configuration for cutting off an electric signal having a frequency as a pass band, a wide band filter can be formed efficiently.
(B) In the conventional filter, the specific band cannot exceed 20%, but even a filter having a specific band of 50% or more can be easily made.

以下、本発明を図の具体例を用いて詳細に説明する。 Hereinafter, the present invention will be described in detail using specific examples of the drawings.

（第１の具体例）
図１に、本発明の誘電体共振器の第１の具体例斜視図を示す。 (First specific example)
FIG. 1 shows a perspective view of a first specific example of a dielectric resonator according to the present invention.

本例は比誘電率εr=４２で縦×横×厚さが１４×５×１mmなる誘電体基板の一方の主面を入出力端部分近傍を除きほぼ全面接地電極とし、他方の主面に２本の先端部分の導体を前記全面アース電極まで延ばした先端短絡となる幅０．２ｍｍのマイクロストリップラインを０．０８mmの間隔で向き合うように配置した。これらの共振器の他端はそのまま入出力部となる。図２に本具体例の電気特性を示す。 In this example, one principal surface of a dielectric substrate having a relative permittivity εr = 42, length × width × thickness 14 × 5 × 1 mm is used as a substantially ground electrode except for the vicinity of the input / output end portion, and the other principal surface is Microstrip lines with a width of 0.2 mm that are short-circuited with the conductors of the two tip portions extending to the entire ground electrode were arranged to face each other at an interval of 0.08 mm. The other ends of these resonators directly serve as input / output units. FIG. 2 shows the electrical characteristics of this example.

（第２の具体例）
図３に、本発明の誘電体フィルタの第２の具体例分解斜視図、図４に具体例斜視図を示す。
本具体例においては４枚の誘電体層を接地電極となる全面に形成された導体を介して積層し、また最低面、最上面にも全面接地電極を設け、それぞれの誘電体層中にストリップラインを設置することにより構成されている。 (Second specific example)
FIG. 3 shows an exploded perspective view of a second specific example of the dielectric filter of the present invention, and FIG. 4 shows a specific example perspective view.
In this specific example, four dielectric layers are laminated via a conductor formed on the entire surface to be a ground electrode, and a ground electrode is also provided on the bottom and top surfaces, and strips are provided in the respective dielectric layers. It is configured by installing a line.

各誘電体層の大きさは縦×横×厚さが３０×８×０．５mmで、図中下から第１層はεr=７．７、第２層はεr=７５、第３層はεr=７５、第４層はεr=７．７である。第１層には入出力より延び、先端がスルーホールにて上下の導体層に接続されて長さ２７mm、幅０．０５mmの凡そ１GHｚにて１／４波長先端短絡共振器となる第１の線路が、該線路と並び０．０２mmの間隔をおいて先端開放となる同じ長さの第２の線路が設置してある。該第２の線路は入出力部の直ぐ隣で誘電体の側面で上方に延出され第２の誘電体層に入る。第２の誘電体層に入り、幅０．１８mm、長さ８．７mmの第３の線路を経由し、スルーホールにて上下の導体に接地される。該第３の線路の隣には０．０２mmの間隔をおいて同じく幅０．１８mm、長さ８．７mmの第４の線路が先端開放状態で併設されている。 The size of each dielectric layer is vertical × horizontal × thickness 30 × 8 × 0.5 mm. From the bottom in the figure, the first layer is εr = 7.7, the second layer is εr = 75, and the third layer is εr = 75 and the fourth layer has εr = 7.7. The first layer extends from the input / output, and the tip is connected to the upper and lower conductor layers through holes, and becomes a 1/4 wavelength tip short-circuit resonator at approximately 1 GHz with a length of 27 mm and a width of 0.05 mm. A second line of the same length is installed in which the line is aligned with the line and the tip is open at an interval of 0.02 mm. The second line extends upward on the side surface of the dielectric immediately adjacent to the input / output unit and enters the second dielectric layer. It enters the second dielectric layer, passes through a third line having a width of 0.18 mm and a length of 8.7 mm, and is grounded to the upper and lower conductors through holes. Next to the third line, a fourth line having a width of 0.18 mm and a length of 8.7 mm is also provided with an open end at an interval of 0.02 mm.

第２の誘電体層は比誘電率が高いので長さ８．７mmで第１の誘電体層と同様の共振周波数が得られる。該第４の導体は誘電体の側面で上方に延出され、第３の誘電体層に入る。 Since the second dielectric layer has a high relative dielectric constant, a resonance frequency similar to that of the first dielectric layer can be obtained with a length of 8.7 mm. The fourth conductor extends upward at the side of the dielectric and enters the third dielectric layer.

本願のフィルタは第２の誘電体層と第３の誘電体層の間の導体層を中心に全くの面対称構造になっており、第３，第４の誘電体層中に合計４本の線路が形成され他方の入出力に連なる。 The filter of the present application has a completely plane-symmetric structure centering on the conductor layer between the second dielectric layer and the third dielectric layer, and a total of four filters are included in the third and fourth dielectric layers. A line is formed and continues to the other input / output.

図５に本具体例の等価回路を、図６に電気特性を示す。 FIG. 5 shows an equivalent circuit of this example, and FIG. 6 shows electrical characteristics.

本発明は以上の具体例に限定されるものではない。
共振器や結合線路が得られる構成であればマイクロストリップライン、ストリップラインに拘る物ではない。基板を基本とする物ではなく誘電体ブロック中に共振器や結合線路を形成したものであっても構わない。更に従来のフィルタと同様に更に共振器や線路を追加して通過帯域の近傍に減衰極を設置して減衰特性を改善する事も可能である。 The present invention is not limited to the above specific examples.
The configuration is not related to the microstrip line and the strip line as long as the resonator and the coupled line can be obtained. A resonator or a coupled line formed in a dielectric block may be used instead of a substrate-based one. Furthermore, as with the conventional filter, it is possible to add a resonator or a line and install an attenuation pole in the vicinity of the pass band to improve the attenuation characteristic.

また何本の線路を組み合わせて何段のフィルタを作ろうともそれらは設計事項である。上に挙げた具体例においては先端短絡部は線路を全面接地電極まで延出したり、スルーホールにより接地電極に接続したが線路と同一面に接地電極を形成しても良い。 In addition, no matter how many lines are combined to create a number of stages of filters, they are design matters. In the specific examples given above, the short circuit portion at the tip extends the line to the entire ground electrode or is connected to the ground electrode by a through hole, but the ground electrode may be formed on the same surface as the line.

本願発明のフィルタの第１の具体例の斜視図を示す。The perspective view of the 1st specific example of the filter of this invention is shown. 本願発明のフィルタの第１の具体例の電気特性を示す。The electrical characteristic of the 1st specific example of the filter of this invention is shown. 本願発明のフィルタの第２の具体例の分解斜視図を示す。The disassembled perspective view of the 2nd specific example of the filter of this invention is shown. 本願発明のフィルタの第２の具体例の斜視図を示す。The perspective view of the 2nd example of the filter of this invention is shown. 本願発明のフィルタの第２の具体例の等価回路を示す。The equivalent circuit of the 2nd example of the filter of this invention is shown. 本願発明のフィルタの第２の具体例の電気特性を示す。The electrical characteristic of the 2nd specific example of the filter of this invention is shown.

符号の説明Explanation of symbols

１接地電極
２入出力部電極
３第１の線路
４第２の線路
５第３の線路孔
６第４の線路
７第５の線路
８第６の線路
９第７の線路
１０第８の線路
１１第１の誘電体層
１２第２の誘電体層
１３第３の誘電体層
１４第４の誘電体層
１５側面接地電極
DESCRIPTION OF SYMBOLS 1 Ground electrode 2 Input / output part electrode 3 1st track 4 2nd track 5 3rd track hole 6 4th track 7 5th track 8 6th track 9 7th track 10 8th track 11 1st dielectric layer 12 2nd dielectric layer 13 3rd dielectric layer 14 4th dielectric layer 15 Side surface ground electrode

Claims

入力端及び／又は出力端に他端を接地する並列共振器となる伝送線を直接接続してなる比帯域２０％を越える広帯域誘電体フィルタ。 A broadband dielectric filter having a specific bandwidth exceeding 20%, wherein a transmission line serving as a parallel resonator having the other end grounded to an input end and / or an output end is directly connected.

更に入力端及び／又は出力端からフィルタ内部に向けて直列共振器となる結合線路が直接接続されている請求項１に記載の広帯域誘電体フィルタ。 The broadband dielectric filter according to claim 1, further comprising a coupling line serving as a series resonator directly connected from an input end and / or an output end toward the inside of the filter.

前記並列共振器及び直列共振器はストリップラインにより構成されていることを特徴とする請求項１又は２に記載の広帯域誘電体フィルタ。 3. The broadband dielectric filter according to claim 1, wherein the parallel resonator and the series resonator are configured by strip lines.

前記並列共振器及び直列共振器はマイクロストリップラインにより構成されていることを特徴とする請求項１又は２に記載の広帯域誘電体フィルタ。 3. The broadband dielectric filter according to claim 1, wherein the parallel resonator and the series resonator are configured by a microstrip line.