JP2671571B2 - Microwave filter - Google Patents
Microwave filterInfo
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- JP2671571B2 JP2671571B2 JP17601490A JP17601490A JP2671571B2 JP 2671571 B2 JP2671571 B2 JP 2671571B2 JP 17601490 A JP17601490 A JP 17601490A JP 17601490 A JP17601490 A JP 17601490A JP 2671571 B2 JP2671571 B2 JP 2671571B2
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- wavelength
- band
- stubs
- frequency
- length
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Description
【発明の詳細な説明】 産業上の利用分野 本発明はストリップ線路またはマイクロ波ストリップ
線路を用いたマイクロ波フィルタに関し、特に阻止域周
波数が通過域周波数の両側に隣接して存在し、かつ、通
過域周波数，阻止域周波数ともに帯域幅が有限な場合の
帯域通過型のマイクロ波フィルタに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave filter using a strip line or a microwave strip line, and in particular, a stop band frequency exists adjacent to both sides of a pass band frequency and a pass band frequency is present. The present invention relates to a band-pass type microwave filter in which both band frequencies and stop band frequencies have finite bandwidths.
従来の技術 ある帯域の信号のみを取りだし、それ以外の信号を除
去したい場合にはフィルタがよく用いられる。特に取り
出したい信号の周波数帯が除去したい信号の周波数帯に
挟まれている場合、すなわち阻止域周波数帯が通過域周
波数帯の高域側と低域側の両側に隣接して存在する場合
には、帯域通過フィルタが用いられる。第４図に従来例
による帯域通過フィルタの構成例を示す。この帯域通過
フィルタは両端が開放された半波長ストリップ線路を共
振器として用いたもので、入力端子１、出力端子２との
間で入力ストリップ線路３、出力ストリップ線路４およ
び半波長ストリップ線路共振器５が1/4波長の長さにわ
たって、隣接する半波長ストリップ線路共振器と逐次分
布結合して構成されたものである。2. Description of the Related Art A filter is often used to take out only a signal in a certain band and remove the other signals. Especially when the frequency band of the signal to be extracted is sandwiched between the frequency bands of the signals to be removed, that is, when the stop band frequency band is adjacent to both the high band side and the low band side of the pass band frequency band. , A bandpass filter is used. FIG. 4 shows a configuration example of a conventional bandpass filter. This band-pass filter uses a half-wave strip line having both ends open as a resonator, and has an input strip line 3, an output strip line 4, and a half-wave strip line resonator between an input terminal 1 and an output terminal 2. Numeral 5 is formed by sequentially distributed coupling with an adjacent half-wavelength strip line resonator over a length of 1/4 wavelength.
発明が解決しようとする課題 以上述べた従来例では、フィルタの構成要素である半
波長ストリップ線路共振器５の段数を増やすことでフィ
ルタの帯域外特性を急峻にすることができる。しかし、
この半波長ストリップ線路共振器５の無負荷Ｑ値は高く
なく、10GHz帯では数百程度であるためフィルタの段数
を増やすと、フィルタ寸法が大きくなるとともに通過域
での挿入損失が増大する。従って通過域での挿入損失が
小さく帯域外特性の急峻なフィルタを得ることは困難で
ある。DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the conventional example described above, the out-of-band characteristics of the filter can be made sharp by increasing the number of stages of the half-wavelength strip line resonator 5 which is a constituent element of the filter. But,
The unloaded Q value of the half-wavelength strip line resonator 5 is not high, and is about several hundreds in the 10 GHz band. Therefore, if the number of filter stages is increased, the filter size increases and the insertion loss in the pass band increases. Therefore, it is difficult to obtain a filter having a small insertion loss in the pass band and a steep out-of-band characteristic.
本発明はかかる点に鑑みてなされたもので、簡単な構
成で上記従来例のもつ欠点を除去し、通過帯域では挿入
損失が小さく、阻止帯域では挿入損失が十分に大きく、
急峻な立ち上がり特性を有するとともに、通過帯域およ
び阻止帯域とも十分な帯域幅を有する帯域通過型のマイ
クロ波フィルタを提供することを目的とする。The present invention has been made in view of the above points, eliminates the drawbacks of the above-described conventional example with a simple configuration, the insertion loss is small in the pass band, the insertion loss is sufficiently large in the stop band,
An object of the present invention is to provide a band-pass type microwave filter having a steep rising characteristic and having a sufficient bandwidth in both the pass band and the stop band.
課題を解決するための手段 上記課題を解決するために本発明のマイクロ波フィル
タは、２種類の帯域阻止フィルタの縦続接続で構成さ
れ、それぞれの帯域阻止フィルタは主線路に並列に設け
られた３本の終端開放スタブで構成される。つまり、一
方の帯域阻止フィルタでは主線路の３ヶ所に等間隔また
はほぼ等間隔に終端開放スタブを順次接続し、それらの
終端開放スタブの長さを通過帯域よりも高域側にある阻
止域周波数のほぼ1/4波長の長さに選ぶとともに、それ
らの３本の終端開放スタブの中で一番内側にある終端開
放スタブの長さを最も長く選ぶことにより、通過帯域の
高域側に阻止帯域を有する帯域阻止フィルタが得られる
ようにしたものである。しかも、終端開放スタブの設け
られている間隔を通過域周波数の1/16波長の長さよりも
長く、通過域周波数の3/16波長の長さよりも短く選ぶこ
とにより、特にすぐれた帯域阻止フィルタ特性が得られ
るように構成している。他方の帯域阻止フィルタでは主
線路の３ヶ所に等間隔またはほぼ等間隔に終端開放スタ
ブを順次接続し、それらの終端開放スタブの長さを通過
帯域よりも低域側にある阻止域周波数のほぼ1/4波長の
長さに選ぶとともに、それらの３本の終端開放スタブの
中で一番内側にある終端開放スタブの長さを最も短く選
ぶことにより、通過帯域の低域側に阻止帯域を有する帯
域阻止フィルタが得られるようにしたものである。しか
も、終端開放スタブの設けられている間隔を通過域周波
数の5/16波長の長さよりも長く、通過域周波数の7/16波
長の長さよりも短く選ぶことにより、特にすぐれた帯域
阻止フィルタ特性が得られるように構成している。前記
２種類の帯域阻止フィルタ特性から希望する帯域通過フ
ィルタ特性を得ている。Means for Solving the Problems In order to solve the above problems, the microwave filter of the present invention is configured by cascading two types of band stop filters, and each band stop filter is provided in parallel with a main line. The book consists of open stubs. That is, in one of the band elimination filters, open-ended stubs are sequentially connected to the main line at three locations at equal or almost equal intervals, and the lengths of the open-ended stubs are set to the stopband frequency higher than the passband. Of 1/4 wavelength, and by selecting the longest length of the innermost open stub among these three open stubs, the high-pass side of the pass band is blocked. A band stop filter having a band is obtained. Moreover, by selecting the interval at which the open-ended stub is provided to be longer than the length of 1/16 wavelength of the passband frequency and shorter than the length of 3/16 wavelength of the passband frequency, particularly excellent band stop filter characteristics Is configured so that In the other band elimination filter, open-ended stubs are sequentially connected to the main line at three locations at equal or nearly equal intervals, and the lengths of these open-ended stubs are set to be almost equal to the stopband frequency on the lower side of the passband. By selecting the length of 1/4 wavelength and selecting the shortest length of the innermost open stub among these three open stubs, the stop band is set to the low side of the pass band. The band stop filter is included. Moreover, by selecting the interval at which the open end stubs are provided to be longer than the length of 5/16 wavelength of the passband frequency and shorter than the length of 7/16 wavelength of the passband frequency, the band stop filter characteristic is particularly excellent. Is configured so that A desired bandpass filter characteristic is obtained from the two types of bandstop filter characteristics.
作用 本発明によれば、上記した構成により、通過帯域内で
は挿入損失が小さく、阻止帯域では挿入損失が十分に大
きく、急峻な立ち上がり特性を有するとともに通過帯域
および阻止帯域とも十分な帯域幅を有する帯域通過型の
マイクロ波フィルタが得られる。Effect According to the present invention, with the above-described configuration, the insertion loss is small in the pass band, the insertion loss is sufficiently large in the stop band, the steep rising characteristics are provided, and the pass band and the stop band have a sufficient bandwidth. A band pass type microwave filter is obtained.
実施例 第１図は本発明による帯域通過型マイクロ波フィルタ
の一実施例を示すもので、入力端子11および出力端子12
をストリップ線路で構成される主線路13で結び、主線路
13に長さがそれぞれl1,l2,l3の終端開放ストリップ14,1
5,16を等間隔に間隔l0で順次並列に接続し、さらに長さ
がそれぞれl4,l5,l6の終端開放スタブ17,18,19等を間隔
に間隔l0′で順次並列に接続している。終端開放スタブ
14,15,16の長さl1,l2,l3は通過帯域よりも高域側にある
阻止域周波数の帯域内あるいは帯域近傍に減衰極がくる
ように阻止域周波数の1/4波長あるいはほぼ1/4波長の長
さに選ぶ。そして終端開放スタブ14,15,16の長さl1,l2,
l3および間隔l0はl2/4＜l0＜l1＜l2かつl2/4＜l0＜l3＜
l2の条件を満足するか、あるいはl2/4＜l0＜l1＝l3＜l2
の条件を満足するように選ぶとともに、l0の長さは通過
域周波数の1/4波長の0.5倍前後に選んでいる。一方、終
端開放スタブ17,18,19の長さl4,l5,l6は通過帯域よりも
低域側にある阻止域周波数の帯域内あるいは帯域近傍に
減衰極がくるように阻止域周波数の1/4波長あるいはほ
ぼ1/4波長の長さに選ぶ。そして終端開放スタブ17,18,1
9の長さl4,l5,l6および間隔l0′はl5＜l4＜l0′＜2l5か
つl5＜l6＜l0′＜2l5の条件を満足するか、あるいはl5
＜l4＝l6＜l0′＜2l5の条件を満足するように選ぶとと
もに、l0′の長さは通過域周波数の1/4波長の1.5倍前後
に選んでいる。Embodiment FIG. 1 shows an embodiment of a band-pass type microwave filter according to the present invention, which has an input terminal 11 and an output terminal 12.
To the main line 13 composed of strip lines,
13 open-ended strips with lengths l 1 , l 2 and l 3 respectively 14 and 1
5, 16 are connected in parallel at equal intervals with an interval of l 0 , and further, open-end stubs 17, 18, 19 etc. having lengths of l 4 , l 5 , l 6 are connected in parallel with an interval of l 0 ′. Connected to. Termination open stub
The length of 14,15,16 l 1, l 2, l 3 1/4 wavelength of the stop band frequency as attenuation pole comes to in-band or band near the stopband frequencies in the high frequency side than the pass band Or choose a length of about 1/4 wavelength. And the length of the open end stubs 14, 15, 16 l 1 , l 2 ,
l 3 and spacing l 0 is l 2/4 <l 0 < l 1 <l 2 and l 2/4 <l 0 < l 3 <
or satisfies the condition of l 2, or l 2/4 <l 0 < l 1 = l 3 <l 2
The length of l 0 is selected to be around 0.5 times the 1/4 wavelength of the passband frequency while satisfying the condition of. On the other hand, the lengths l 4 , l 5 , l 6 of the open-ended stubs 17, 18, 19 are the stopband frequencies so that the attenuation poles come within or near the stopband frequencies on the lower side of the passband. Choose a length of 1/4 wavelength or almost 1/4 wavelength. And the open end stub 17,18,1
The lengths l 4 , l 5 , l 6 of 9 and the interval l 0 ′ satisfy the conditions of l 5 <l 4 <l 0 ′ <2l 5 and l 5 <l 6 <l 0 ′ <2l 5 Or l 5
It is selected so as to satisfy the condition of <l 4 = l 6 <l 0 ′ <2l 5 and the length of l 0 ′ is selected to be about 1.5 times the quarter wavelength of the pass band frequency.
第２図は本発明による帯域通過型マイクロ波フィルタ
の他の実施例を示すもので、第１図と同一箇所には同一
番号を付して説明する。第２図の実施例では終端開放ス
タブ16と終端開放スタブ17とは主線路13の両側で同じ位
置に接続されているが、それ以外は第１図と構成は全く
同じである。入力端子11および出力端子12をストリップ
線路で構成される主線路13で結び、主線路13に長さがそ
れぞれl1,l2,l3の終端開放スタブ14,15,16を等間隔に間
隔l0で順次並列に接続し、さらに長さがそれぞれl4,l5,
l6の終端開放スタブ17,18,19を等間隔に間隔l0′で順次
並列に接続している。そして、終端開放スタブ16と終端
開放スタブ17とは主線路13の両側で同じ位置に接続され
ている。終端開放スタブ14,15,16の長さl1,l2,l3は通過
帯域よりも高域側にある阻止域周波数の帯域内あるいは
帯域近傍に減衰極がくるように阻止域周波数の1/4波長
あるいはほぼ1/4波長の長さに選ぶ。そして終端開放ス
タブ14,15,16の長さl1,l2,l3および間隔l0はl2/4＜l0＜
l1＜l2かつl2/4＜l0＜l3＜l2の条件を満足するか、ある
いはl2/4＜l0＜l1＝l3＜l2の条件を満足するように選ぶ
とともに、l0の長さは通過域周波数の1/4波長の0.5倍前
後に選んでいる。一方終端開放スタブ17,18,19の長さ
l4,l5,l6は通過帯域よりも低域側にある阻止域周波数の
帯域内あるいは帯域近傍に減衰極がくるように阻止域周
波数の1/4波長あるいはほぼ1/4波長の長さに選ぶ。そし
て終端開放スタブ17,18,19の長さl4,l5,l6および間隔
l0′はl5＜l4＜l0′＜2l5かつl5＜l6＜l0′＜2l5の条件
を満足するか、あるいはl5＜l4＝l6＜l0′＜2l5の条件
を満足するように選ぶとともに、l0′の長さは通過域周
波数の1/4波長の1.5倍前後に選んでいる。FIG. 2 shows another embodiment of the band-pass type microwave filter according to the present invention. The same parts as those in FIG. In the embodiment of FIG. 2, the open-end stub 16 and open-end stub 17 are connected to the same position on both sides of the main line 13, but otherwise the configuration is exactly the same as in FIG. The input terminal 11 and the output terminal 12 are connected by a main line 13 composed of a strip line, and open-ended stubs 14, 15, 16 of lengths l 1 , l 2 , l 3 are equally spaced on the main line 13. l 0 are connected in parallel in sequence, and the lengths are l 4 , l 5 ,
The open stubs 17, 18 and 19 of l 6 are connected in parallel at equal intervals at intervals of l 0 ′. The open-end stub 16 and open-end stub 17 are connected to the same position on both sides of the main line 13. The lengths l 1 , l 2 and l 3 of the open-ended stubs 14, 15 and 16 are 1 of the stopband frequency so that the attenuation pole is located in or near the stopband frequency higher than the passband. Select a length of / 4 wavelength or almost 1/4 wavelength. And the length l 1, l 2, l 3 and spacing l 0 end open stub 14, 15 and 16 l 2/4 <l 0 <
l 1 <l 2 and l 2/4 <l 0 <or satisfies the condition l 3 <l 2, or l 2/4 <l 0 < l 1 = l 3 < so as to satisfy the condition l 2 Along with the choice, the length of l 0 is chosen to be around 0.5 times 1/4 wavelength of the passband frequency. On the other hand, the length of the open stub 17, 18, 19
l 4 , l 5 and l 6 are 1/4 wavelength or almost 1/4 wavelength of the stopband frequency so that the attenuation pole is located in or near the stopband frequency on the lower side of the passband. Choose And the length l 4 , l 5 , l 6 of the open end stubs 17, 18, 19 and the spacing
l 0 ′ satisfies the conditions of l 5 <l 4 <l 0 ′ <2l 5 and l 5 <l 6 <l 0 ′ <2l 5 or l 5 <l 4 = l 6 <l 0 ′ < The length of l 0 ′ is selected to be about 1.5 times the 1/4 wavelength of the pass band frequency, while satisfying the condition of 2l 5 .
第３図は第２図において、ストリップ線路用誘電体基
板の比誘電率を2.5、主線路の特性インピーダンスZoを5
0オーム、終端開放スタブ14,15,16,17,18,19の特性イン
ピーダンスZsをすべて90オームとした場合に、l0＝1.8m
m、l1＝l3＝3.53mm、l2＝3.98mm、l0′＝6.4mm、l4＝l6
＝5.73mm、l5＝5.13mmの時のフィルタ特性を示したもの
である。第３図に示すフィルタでは周波数が11.6〜12.5
GHzの範囲では反射損失は14dB以上であり、8.8〜10.6GH
zの周波数範囲と13.3〜16.2GHzの周波数範囲では30dB以
上の減衰量を有する特性が得られている。従って、第３
図に示すような特性を有するフィルタは、通過帯域が1
1.6〜12.5GHzの周波数範囲にあり、阻止帯域が8.8〜10.
6GHzと13.3〜16.2GHzの周波数範囲にある帯域通過型の
マイクロ波フィルタとして十分に機能するものである。
これは、阻止域周波数が通過域周波数帯の両側に隣接し
て存在し、かつ、通過域周波数，阻止域周波数ともに帯
域幅が有限な場合の帯域通過型のマイクロ波フィルタと
して特に有効である。Fig. 3 shows that in Fig. 2, the dielectric constant of the stripline dielectric substrate is 2.5 and the characteristic impedance Zo of the main line is 5
When the characteristic impedance Zs of 0 ohm and open-ended stubs 14,15,16,17,18,19 are all 90 ohms, l 0 = 1.8m
m, l 1 = l 3 = 3.53 mm, l 2 = 3.98 mm, l 0 ′ = 6.4 mm, l 4 = l 6
= 5.73 mm, l 5 = 5.13 mm. In the filter shown in Fig. 3, the frequencies are 11.6 to 12.5.
Return loss is more than 14dB in the GHz range, 8.8-10.6GH
In the frequency range of z and the frequency range of 13.3 to 16.2 GHz, a characteristic having an attenuation of 30 dB or more is obtained. Therefore, the third
A filter with the characteristics shown in the figure has a pass band of 1
It is in the frequency range of 1.6 to 12.5 GHz and has a stop band of 8.8 to 10.
It functions well as a bandpass microwave filter in the frequency range of 6 GHz and 13.3 to 16.2 GHz.
This is particularly effective as a band-pass type microwave filter in which the stop band frequencies are adjacent to each other on both sides of the pass band frequency band and both the pass band frequencies and the stop band frequencies have finite bandwidths.
以上説明したように第１図および第２図に示した本発
明によれば、主線路に終端開放スタブを順次並列に接続
した構成であるため通過帯域での挿入損失を少なくでき
る。また、２種類のほぼ独立した帯域阻止フィルタで構
成されているため、通過帯域の低域側と高域側の特性を
独立して設計でき、したがってフィルタ全体の設計が簡
素化される。しかも、通過帯域の高域側にある阻止帯域
の特性については、３本の終端開放スタブの長さl1,l2,
l3は通過帯域よりも高域側にある阻止域周波数の帯域内
あるいは帯域近傍に減衰極がくるように阻止域周波数の
1/4波長あるいはほぼ1/4波長の長さに選ぶ。そして終端
開放スタブの長さl1,l2,l3および間隔l0はl2/4＜l0＜l1
＜l2かつl2/4＜l0＜l3＜l2の条件を満足するか、あるい
はl2/4＜l0＜l1＝l3＜l2の条件を満足するように選ぶこ
とにより、通過帯域の高域側での減衰特性が急峻で、阻
止帯域での減衰量が大きいフィルタを簡単な構成により
実現することができる。As described above, according to the present invention shown in FIGS. 1 and 2, since the open-ended stubs are sequentially connected in parallel to the main line, the insertion loss in the pass band can be reduced. In addition, since it is composed of two types of almost independent band elimination filters, the characteristics of the low band side and the high band side of the pass band can be designed independently, and therefore the design of the entire filter is simplified. Moreover, regarding the characteristics of the stop band on the higher side of the pass band, the lengths l 1 , l 2 ,
l 3 is the stopband frequency so that the attenuation pole is in or near the stopband frequency that is higher than the passband.
Choose a length of 1/4 wavelength or almost 1/4 wavelength. And the length l 1 of the open-ended stub, l 2, l 3 and intervals l 0 is l 2/4 <l 0 < l 1
<L 2 and l 2/4 <l 0 < l 3 < or satisfies the condition of l 2, or l 2/4 <l 0 < l 1 = l 3 < be chosen to satisfy the condition of l 2 Thus, it is possible to realize a filter having a steep attenuation characteristic on the high band side of the pass band and a large attenuation amount on the stop band with a simple configuration.
さらに、通過帯域の低域側にある阻止帯域での特性に
ついては、３本の終端開放スタブの長さl4,l5,l6は通過
帯域よりも低域側にある阻止域周波数の帯域内あるいは
帯域近傍に減衰極がくるように阻止域周波数の1/4波長
あるいはほぼ1/4波長の長さに選ぶ。そして終端開放ス
タブの長さl4,l5,l6および間隔l0′はl5＜l4＜l0′＜2l
5かつl5＜l6＜l0′＜2l5の条件を満足するか、あるいは
l5＜l4＝l6＜l0′＜2l5の条件を満足するように選ぶこ
とにより、通過帯域の低域側での減衰特性が急峻で、阻
止帯域での減衰量が大きいフィルタを簡単な構成により
実現することができる。また第１図，第２図の説明では
２種類の帯域阻止フィルタを構成するそれぞれ３本の終
端開放スタブの間隔l0およびl0′はそれぞれ等間隔であ
るが、それぞれの間隔は必ずしも正確に等間隔である必
要はなく、ほぼ等間隔であればフィルタ特性は等間隔の
場合と大きくずれることはない。さらに、フィルタ特性
を実際に計算すれば、終端開放スタブの間隔l0として、
通過域周波数の1/16波長よりも長く3/16波長よりも短い
1/8波長前後に選ぶと、特に通過帯域の高域側にある阻
止帯域で急峻な減衰特性をもつすぐれたフィルタが構成
でき終端開放スタブの間隔l0′として、通過域周波数の
5/16波長よりも長く7/16波長よりも短い3/8波長前後に
選ぶと、特に通過帯域の低域側にある阻止帯域で急峻な
減衰特性をもつすぐれたフィルタが構成でき、第３図の
特性を有するフィルタは、この条件を満足するようなフ
ィルタ寸法に選ばれている。Furthermore, regarding the characteristics in the stop band on the lower side of the pass band, the lengths l 4 , l 5 , and l 6 of the three open-ended stubs are the bands of stop band frequencies on the lower side of the pass band. Select a length of 1/4 wavelength or almost 1/4 wavelength of the stopband frequency so that the attenuation pole is within or near the band. The lengths l 4 , l 5 , l 6 of the open end stub and the interval l 0 ′ are l 5 <l 4 <l 0 ′ <2l
5 and satisfy the condition of l 5 <l 6 <l 0 ′ <2l 5 or
By selecting so that the condition of l 5 <l 4 = l 6 <l 0 ′ <2l 5 is satisfied, a filter having a steep attenuation characteristic in the low band side of the pass band and a large attenuation amount in the stop band is selected. It can be realized with a simple configuration. Further, in the explanations of FIGS. 1 and 2, the intervals l 0 and l 0 ′ of the three open-ended stubs constituting the two types of band elimination filters are equal intervals, but the intervals are not always accurate. It is not necessary that they are evenly spaced, and if they are substantially equally spaced, the filter characteristics will not differ significantly from the case of evenly spaced. Furthermore, if the filter characteristics are actually calculated, the interval l 0 between the open stubs is
Longer than 1/16 wavelength of pass band frequency and shorter than 3/16 wavelength
By selecting around 1/8 wavelength, an excellent filter with a sharp attenuation characteristic can be constructed especially in the stop band on the high side of the pass band, and the interval l 0 ′ of the open stubs can be set as the pass band frequency.
By selecting around 3/8 wavelength longer than 5/16 wavelength and shorter than 7/16 wavelength, it is possible to construct an excellent filter with sharp attenuation characteristics especially in the stop band on the lower side of the pass band. The filter having the characteristics shown in the figure is selected to have a filter size that satisfies this condition.
発明の効果 以上のように本発明によれば次の効果を得ることがで
きる。Effects of the Invention As described above, according to the present invention, the following effects can be obtained.
（１） フィルタの構成要素は終端開放スタブのみで、
主線路の長さは通過域周波数の約１波長と短くフィルタ
寸法が小さく製作できる。(1) The only component of the filter is the open stub,
The length of the main line is as short as about 1 wavelength of the pass band frequency, and the filter size can be made small.
（２） 連続した主線路に並列に終端開放スタブを接続
した構成としたため通過帯域での挿入損失を少なくでき
る。(2) Since the open stub is connected in parallel to the continuous main line, the insertion loss in the pass band can be reduced.
（３） ２種類の帯域阻止フィルタが縦続接続して構成
されているため、通過帯域の低域側と高域側の特性をほ
ぼ独立して設計できるとともにフィルタ全体の設計が簡
素化される。(3) Since the two types of band elimination filters are connected in cascade, the characteristics of the low band side and the high band side of the pass band can be designed almost independently and the design of the entire filter is simplified.
（４） 通過帯域の高域側にある阻止帯域での特性につ
いては３本の終端開放スタブの長さl1,l2,l3は阻止域周
波数の帯域内あるいは帯域近傍に減衰極がくるように阻
止域周波数の1/4波長あるいはほぼ1/4波長の長さに選
び、そして終端開放スタブの長さl1,l2,l3および間隔l0
はl2/4＜l0＜l1＜l2かつl2/4＜l0＜l3＜l2の条件を満足
するか、あるいはl2/4＜l0＜l1＝l3＜l2の条件を満足す
るように選ぶことにより、通過帯域の高域側での減衰特
性が急峻で、阻止帯域での減衰量が大きいフィルタを簡
単な構成により実現することができる。(4) Regarding the characteristics in the stop band on the higher side of the pass band, the lengths l 1 , l 2 and l 3 of the three open end stubs have attenuation poles within or near the stop band frequency. To the length of 1/4 wavelength or almost 1/4 wavelength of the stopband frequency, and the lengths l 1 , l 2 , l 3 of the open-ended stub and the spacing l 0
Is l 2/4 <l 0 < l 1 <l 2 and l 2/4 <l 0 < l 3 < or satisfies the condition of l 2, or l 2/4 <l 0 < l 1 = l 3 < By selecting so as to satisfy the condition of l 2 , it is possible to realize a filter having a steep attenuation characteristic in the high band side of the pass band and a large attenuation amount in the stop band with a simple configuration.
（５） 通過帯域の低域側にある阻止帯域での特性につ
いては３本の終端開放スタブの長さl4,l5,l6は阻止域周
波数の帯域内あるいは帯域近傍に減衰極がくるように阻
止域周波数の1/4波長あるいはほぼ1/4波長の長さに選
び、そして終端開放スタブの長さl4,l5,l6および間隔
l0′はl5＜l4＜l0′＜2l5かつl5＜l6＜l0′＜2l5の条件
を満足するか、あるいはl5＜l4＝l6＜l0′＜2l5の条件
を満足するように選ぶことにより、通過帯域の低域側で
の減衰特性が急峻で、阻止帯域での減衰量が大きいフィ
ルタを簡単な構成により実現することができる。(5) Regarding the characteristics in the stop band on the lower side of the pass band, the three end-open stub lengths l 4 , l 5 , l 6 have attenuation poles in or near the stop band frequency band. The length of the 1/4 wavelength or almost 1/4 wavelength of the stopband frequency, and the length of the open stub l 4 , l 5 , l 6 and the spacing.
l 0 ′ satisfies the conditions of l 5 <l 4 <l 0 ′ <2l 5 and l 5 <l 6 <l 0 ′ <2l 5 or l 5 <l 4 = l 6 <l 0 ′ < By selecting such that the condition of 2l 5 is satisfied, it is possible to realize a filter having a steep attenuation characteristic in the low band side of the pass band and a large attenuation amount in the stop band with a simple configuration.
第１図は本発明によるストリップ線路で構成された帯域
通過型のマイクロ波フィルタ回路の一実施例を示すパタ
ーン図、第２図は本発明によるストリップ線路で構成さ
れた帯域通過型のマイクロ波フィルタ回路の他の実施例
を示すパターン図、第３図は第２図のマイクロ波フィル
タ回路の挿入損失の周波数特性の具体例を示す特性図、
第４図は従来のストリップ線路で構成された帯域通過フ
ィルタのパターン図である。 11……入力端子、12……出力端子、13……主線路、14,1
5,16,17,18,19……終端開放スタブ。FIG. 1 is a pattern diagram showing an embodiment of a band-pass type microwave filter circuit constituted by a strip line according to the present invention, and FIG. 2 is a band pass type microwave filter constituted by a strip line according to the present invention. FIG. 3 is a pattern diagram showing another embodiment of the circuit, FIG. 3 is a characteristic diagram showing a concrete example of frequency characteristics of insertion loss of the microwave filter circuit of FIG.
FIG. 4 is a pattern diagram of a conventional bandpass filter composed of strip lines. 11 …… input terminal, 12 …… output terminal, 13 …… main line, 14,1
5,16,17,18,19 …… Stub with open end.
Claims (4)
と、この主線路に間隔が等間隔か、あるいはほぼ等間隔
のl0で順次並列に設けられ、かつ長さがそれぞれl1,l2,
l3の終端開放の第1,第２および第３のスタブと、前記主
線路に間隔が等間隔か、あるいはほぼ等間隔のl0′で順
次並列に設けられ、かつ長さがそれぞれl4,l5,l6の終端
開放の第4,第５および第６のスタブとで構成され、かつ
前記第1,第２および第３のスタブの長さl1,l2,l3を通過
域周波数よりも高域側にある第１の阻止域周波数の帯域
内に減衰極がくるよう前記第１の阻止域周波数の1/4波
長の長さに遊びl2/4＜l0＜l1＜l2かつl2/4＜l0＜l3＜l2
の条件を満足するか、あるいはl2/4＜l0＜l1＝l3＜l2の
条件を満足するように、l0,l1,l2,l3の長さを選ぶとと
もに、前記第4,第５および第６のスタブの長さl4,l5,l6
を前記通過域周波数よりも低域側にある第２の阻止域周
波数の帯域内に減衰極がくるように前記第２の阻止域周
波数の1/4波長の長さに選び、l5＜l4＜l0′＜2l5かつl5
＜l6＜l0′＜2l5の条件を満足するか、あるいはl5＜l4
＝l6＜l0′＜2l5の条件を満足するように、l0′,l4,l5,
l6の長さを選んだマイクロ波フィルタ。Claim: What is claimed is: 1. A main line having an input terminal and an output terminal, and these main lines are provided in parallel in order at equal or substantially equal intervals l 0 and have lengths l 1 and l 2 respectively. ,
The first, second and third stubs with open ends of l 3 and the main line are sequentially and parallelly provided at equal intervals or substantially equal intervals l 0 ′, and each has a length of l 4 , l 5 , l 6 with open ends 4th, 5th and 6th stubs and passing the lengths l 1 , l 2 and l 3 of said 1st, 2nd and 3rd stubs first stop band play l 2/4 to 1/4 length of the wavelength of the first stop band frequency attenuation pole come manner within the band of frequencies that than frequency to a higher frequency side <l 0 <l 1 <l 2 and l 2/4 <l 0 < l 3 <l 2
Or satisfies the condition, or l 2/4 <l 0 < l 1 = l 3 < so as to satisfy the condition l 2, with choosing the length of l 0, l 1, l 2 , l 3, Lengths of the fourth, fifth and sixth stubs l 4 , l 5 , l 6
Is selected to be a length of 1/4 wavelength of the second stop band frequency so that the attenuation pole is located within the band of the second stop band frequency on the lower side of the pass band frequency, and l 5 <l 4 <l 0 ′ <2 l 5 and l 5
<L 6 <l 0 ′ <2l 5 is satisfied, or l 5 <l 4
= L 6 <l 0 ′ <2l 5 so that l 0 ′, l 4 , l 5 ,
l A microwave filter with a length of 6 .
３のスタブの間隔l0を通過域周波数の1/16波長よりも長
く、3/16波長よりも短くなるように選んだ請求項１記載
のマイクロ波フィルタ。2. The interval l 0 between the first, second and third stubs provided on the main line is selected so as to be longer than 1/16 wavelength of the pass band frequency and shorter than 3/16 wavelength. 2. The microwave filter according to claim 1.
６のスタブの間隔l0′を通過域周波数の5/16波長よりも
長く、7/16波長よりも短くなるように選んだ請求項１記
載のマイクロ波フィルタ。3. An interval l 0 ′ between the fourth, fifth and sixth stubs provided on the main line is set to be longer than the 5/16 wavelength of the pass band frequency and shorter than the 7/16 wavelength. The selected microwave filter according to claim 1.
３のスタブの間隔l0を通過域周波数の1/16波長よりも長
く、3/16波長よりも短くなるように選ぶとともに、前記
主線路に設けられた第4,第５および第６のスタブの間隔
l0′を前記通過域周波数の5/16波長よりも長く、7/16波
長よりも短くなるように選んだ請求項１記載のマイクロ
波フィルタ。4. The distance l 0 between the first, second and third stubs provided on the main line is selected to be longer than 1/16 wavelength of the pass band frequency and shorter than 3/16 wavelength. And the distance between the fourth, fifth and sixth stubs provided on the main line
The microwave filter according to claim 1, wherein l 0 'is selected so as to be longer than 5/16 wavelength and shorter than 7/16 wavelength of the pass band frequency.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17601490A JP2671571B2 (en) | 1990-07-03 | 1990-07-03 | Microwave filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17601490A JP2671571B2 (en) | 1990-07-03 | 1990-07-03 | Microwave filter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0468601A JPH0468601A (en) | 1992-03-04 |
| JP2671571B2 true JP2671571B2 (en) | 1997-10-29 |
Family
ID=16006214
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17601490A Expired - Lifetime JP2671571B2 (en) | 1990-07-03 | 1990-07-03 | Microwave filter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2671571B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6529096B2 (en) * | 2000-05-30 | 2003-03-04 | Matsushita Electric Industrial Co., Ltd. | Dielectric filter, antenna duplexer, and communications appliance |
| JP6362057B2 (en) * | 2013-04-05 | 2018-07-25 | キヤノン株式会社 | Printed circuit board and electronic device |
-
1990
- 1990-07-03 JP JP17601490A patent/JP2671571B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0468601A (en) | 1992-03-04 |
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