EP0440661B1 - Filtre passe-bande haute frequence - Google Patents

Filtre passe-bande haute frequence Download PDF

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Publication number
EP0440661B1
EP0440661B1 EP89908824A EP89908824A EP0440661B1 EP 0440661 B1 EP0440661 B1 EP 0440661B1 EP 89908824 A EP89908824 A EP 89908824A EP 89908824 A EP89908824 A EP 89908824A EP 0440661 B1 EP0440661 B1 EP 0440661B1
Authority
EP
European Patent Office
Prior art keywords
resonator
pass filter
frequency band
input
output
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP89908824A
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German (de)
English (en)
Other versions
EP0440661A1 (fr
Inventor
Dieter Seitzer
Thomas Brockdorff
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
Original Assignee
Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
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Publication date
Application filed by Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV filed Critical Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
Priority to AT89908824T priority Critical patent/ATE95341T1/de
Publication of EP0440661A1 publication Critical patent/EP0440661A1/fr
Application granted granted Critical
Publication of EP0440661B1 publication Critical patent/EP0440661B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/20—Frequency-selective devices, e.g. filters
    • H01P1/201—Filters for transverse electromagnetic waves
    • H01P1/203—Strip line filters
    • H01P1/20327—Electromagnetic interstage coupling
    • H01P1/20354—Non-comb or non-interdigital filters
    • H01P1/20363—Linear resonators

Definitions

  • the present invention relates to a high-frequency bandpass filter according to the preamble of patent claim 1.
  • This coupling is a so-called coupling of parallel lines.
  • this known interdigital filter with three capacitively shortened lambda quarter-resonators a desirable shift of the next pass band, which in the case of half-wave resonators is twice the resonance frequency, to higher frequencies, so that good attenuation at the first harmonic of the center frequency occurs of the pass band can be achieved.
  • the degree of coupling of this known interdigital filter cannot be increased arbitrarily and thus the damping at the resonance frequency cannot be reduced to low damping values without undesired direct coupling of the input resonator to the output resonator, which in turn would impair the blocking characteristics of the interdigital filter.
  • a bandpass filter with parallel-coupled half-wave resonators is also known from the textbook on radio frequency technology cited above, page 207, Figure 4.14 / 6.
  • the known bandpass filter is implemented using strip technology or microstrip technology and comprises a plurality of lambda half-stripline resonators on a substrate, which are offset with respect to one another in the longitudinal direction by lambda quarters.
  • Such a high-frequency band-pass filter structure has large external dimensions. Furthermore, such an unabridged high-frequency bandpass filter cannot be tuned and has a relatively low attenuation at the first harmonic.
  • a high-frequency bandpass filter in stripline technology which has an input coupling line, two center resonators and an output coupling line.
  • the input coupling line and the output coupling line are each designed as idling lines and capacitive coupling elements, which are arranged parallel to one another and unaligned in the direction of their longitudinal extension, that is to say arranged at the same height.
  • the two center resonators are designed as U-shaped, capacitively shortened half-wave resonators, the ends of which are connected to the ground potential and the center of which is connected to a capacitor.
  • the input coupling line and the output coupling line form purely capacitive couplings at a relatively low-resistance point of the center resonators.
  • the entire filter structure cannot be tuned and has no adjustable degree of coupling. It is all the more impossible with this filter to tune its center frequency over a larger frequency range.
  • the object of the present invention is to develop a high-frequency bandpass filter of the type mentioned at the outset in such a way that, with simple manufacture and small external dimensions of the filter, low transmission loss with high attenuation, in particular in the area of the first harmonic or the first harmonic is achieved.
  • the high-frequency bandpass filter according to the invention prevents a direct coupling of the input resonator to the output resonator by means of their arrangement which is offset in the longitudinal direction of the central resonator, as a result of which a high degree of coupling can be achieved which enables a transmission loss of only 1 to 2.5 dB at the transmission frequency without it being too a usual wave formation of the damping curve in the frequency range occurs with such a high degree of coupling.
  • the high-frequency bandpass filter according to the invention not only shows the very high pass loss just mentioned, but also has, depending on the degree of coupling and bandwidth of the pass band, an attenuation of up to -70 dB at the first harmonic.
  • An important advantage of the filter according to the invention is that its characteristics can be simulated by computer, which is not the case with many known filter structures or can only be carried out approximately with considerable effort.
  • the filter according to the invention is suitable for tuning capacitors with adjustable capacitance values or trimmers and can be constructed compactly and inexpensively using microstrip technology.
  • the field of application of the line filter according to the invention not only appears to be limited to frequency processing, but it seems fundamentally possible to use the filter according to the invention also in the power range.
  • the third-order high-frequency bandpass filter which is designated in its entirety by the reference numeral 1, comprises an input resonator 2, a center resonator 3 and an output resonator 4.
  • the resonators 2, 3, 4 are line resonators in strip technology or microstrip technology on a substrate using the conventional etching technique.
  • the substrate has a thickness of approximately 1.5 mm with a relative permeability or effective dielectric constant EPSILON R of approximately 4.0.
  • the input resonator 2 is coupled to the central resonator 3 in parallel.
  • the center resonator 3 is in turn coupled to the output resonator 4 in parallel.
  • the facing each other Ends 5, 6 of the input resonator 2 and the output resonator 4 are connected to ground.
  • the two ends 7, 8 of the center resonator 3 are connected to ground.
  • the center of the center resonator 3 is connected to ground via a first adjustable capacitor 9.
  • the opposite ends 10, 11 of the input resonator 2 and the output resonator 4 are also connected to ground via a second or third adjustable capacitor 12, 13.
  • the input resonator 2 is parallel to the center resonator 3 between one end 7 and the center 14 of the center resonator 3.
  • the output resonator 4 is parallel to the center resonator 3 between the center 14 of the center resonator 3 and the other end 8.
  • the center resonator 3 in conjunction with the first capacitor 9 assigned to it forms a shortened lambda half-line resonator, the length of which, by suitable selection of the capacitance value of the first capacitor, is likewise from 10 to 30%, but preferably about 16%, of the length of a lambda half. Resonators is set.
  • the capacitance value of the first capacitor 9 corresponds with an accuracy of about 2% to twice the capacitance value of the second or third capacitor 12, 13.
  • the ratio of the capacitance values results from the line lengths.
  • the lengths can be changed independently of one another within certain limits, which is accompanied by a corresponding change in the capacitance values.
  • the outer line elements 2, 4 can be shifted slightly parallel to the middle line 3, which facilitates the placement of the middle capacitor 9.
  • the input resonator 2 is connected to an input connection line 15 by means of a direct tap.
  • the output resonator 4 is connected to an output connection line 16 by means of a direct tap.
  • any other coupling can be used in deviation from the exemplary embodiment shown.
  • An important advantage of the high-frequency bandpass filter 1 according to the invention is that its attenuation curve can be simulated by computer. The result of such a simulation is shown in FIG. 2.
  • the calculated attenuation curve shows a transmission loss of less than -1 dB and an attenuation of -65 dB at twice the transmission frequency 2 f B.
  • FIG. 3 shows the actually measured attenuation curve of the embodiment of the high-frequency bandpass filter according to the invention with the dimensioning specified above
  • the computed attenuation curve according to FIG. 2 coincides relatively well with the actually measured attenuation curve according to FIG. 3 the measurement on which FIG. 3 is based, a transmission loss of -1.2 dB was achieved at a transmission frequency f B of 400 MHz.
  • the attenuation at the first harmonic 2 f B is better than -70 dB.
  • the attenuation curve shown in FIG. 3 shows that a very high degree of coupling is achieved at the transmission frequency f B , without the wave formation of the attenuation curve in the frequency range which is usual at such high coupling degrees having to be accepted, such as it occurs in filters with two resonators coupled in parallel.
  • the exemplary embodiment shown of the bandpass filter according to the invention has a very wide tuning range from 360 MHz to 960 MHz with an approximately constant quality.
  • a decisive advantage of the high-frequency bandpass filter according to the invention is that its damping behavior can be simulated with little effort using programs known per se. B. is not possible with an interdigital filter with more than two resonators.
  • Preferred areas of application of the filter according to the invention are in the field of frequency processing technology at frequencies between approximately 50 MHz and 10 GHz. It is also conceivable to use the filter according to the invention as an output filter for transmitters of low power to suppress harmonics.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Control Of Motors That Do Not Use Commutators (AREA)

Abstract

Filtre passe-bande haute fréquence comportant un résonateur d'entrée, un résonateur central et un résonateur de sortie couplés en parallèle. Le résonateur d'entrée et le résonateur de sortie sont des résonateurs quart d'onde à capacité diminuée. Pour améliorer les caractéristiques d'amortissement, le résonateur central se présente sous la forme d'un résonateur demi-onde à capacité diminuée. Le résonateur d'entrée s'étend sur une première partie de la longueur du résonateur central. Le résonateur de sortie s'étend sur une deuxième partie de la longueur du résonateur central.

Claims (11)

  1. Filtre passe-bande haute fréquence
    - à résonateur d'entrée (2), résonateur central (3) et résonateur de sortie (4),
    - le résonateur d'entrée (2) étant couplé en parallèle au résonateur central (3) et le résonateur central (3) au résonateur de sortie (4), et
    - le résonateur d'entrée (2) et le résonateur de sortie (4) se présentant sous forme de quarts de résonateurs de ligne Lambda capacitivement raccourcis,
    caractérisé en ce
    que le résonateur central (3) se présente sous forme de demi-résonateur de ligne Lambda capacitivement raccourci qui est relié, à ses deux extrémités (7, 8), à un potentiel de référence et, en son centre (14), à un premier condensateur (9),
    que le résonateur d'entrée (2) et le résonateur de sortie (4) sont décalés l'un par rapport à l'autre dans le sens de leur extension longitudinale, et
    que le résonateur d'entrée (2) s'étend sur une première partie de la longueur du résonateur central (3) et le résonateur de sortie (4) s'étend sur une deuxième partie du résonateur central (3).
  2. Filtre passe-bande haute fréquence suivant la revendication 1, caractérisé en ce qu'une ligne d'entrée (15) et une ligne de sortie (16) sont raccordées, par un branchement direct, au résonateur d'entrée (2), respectivement résonateur de sortie (4), chacune à un point de raccordement qui se situe entre les extrémités (5, 10; 6, 11) de ces résonateurs (2, 4).
  3. Filtre passe-bande haute fréquence suivant la revendication 1 ou 2, caractérisé en ce que le résonateur d'entrée (2) et le résonateur de sortie (4) sont raccordés, par leurs extrémités orientées l'une vers l'autre (5, 6), à un potentiel de référence et, par leurs extrémités opposées l'une à l'autre (10, 11), à un second, respectivement troisième condensateur (12, 13).
  4. Filtre passe-bande haute fréquence suivant l'une des revendications 1 à 3, caractérisé en ce que la capacité du second, respectivement troisième condensateur (12, 13) est choisie de manière telle que la longueur du résonateur d'entrée (2), respectivement résonateur de sortie (4) est de 10% à 30% de la longueur d'un quart de résonateur Lambda.
  5. Filtre passe-bande haute fréquence suivant la revendication 4, caractérisé en ce que la longueur du résonateur d'entrée (2), respectivement celle du résonateur de sortie (4) est d'environ 15% de la longueur d'un quart de résonateur Lambda.
  6. Filtre passe-bande haute fréquence suivant l'une des revendications 1 à 5, caractérisé en ce que la capacité du premier condensateur (9) est choisie de manière telle que la longueur du résonateur central (3) est de 10% à 30% de la longueur d'un demi-résonateur Lambda.
  7. Filtre passe-bande haute fréquence suivant la revendication 6, caractérisé en ce que la longueur du résonateur central (3) est d'environ 15% de la longueur d'un demi-résonateur Lambda.
  8. Filtre passe-bande haute fréquence suivant l'une des revendications 1 à 7, caractérisé en ce que la capacité du premier condensateur (9) correspond au double de la valeur de capacité du second ou troisième condensateur (12, 134).
  9. Filtre passe-bande haute fréquence suivant l'une des revendications 1 à 8, caractérisé en ce que le filtre (1) est réalisé sur un substrat, suivant la technique des lignes à bandes.
  10. Filtre passe-bande haute fréquence suivant l'une des revendications 1 à 8, caractérisé en ce que le filtre est réalisé avec des lignes distantes d'un corps de base, entourées d'air en tant que diélectrique.
  11. Filtre passe-bande haute fréquence suivant l'une des revendications 1 à 10, caractérisé en ce que les condensateurs (9, 12, 13) sont réglables quant à leur valeur de capacité, aux fins de réglage du filtre passe-bande (1).
EP89908824A 1988-10-18 1989-08-01 Filtre passe-bande haute frequence Expired - Lifetime EP0440661B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT89908824T ATE95341T1 (de) 1988-10-18 1989-08-01 Hochfrequenz-bandpassfilter.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3835480 1988-10-18
DE3835480A DE3835480A1 (de) 1988-10-18 1988-10-18 Hochfrequenz-bandpassfilter

Publications (2)

Publication Number Publication Date
EP0440661A1 EP0440661A1 (fr) 1991-08-14
EP0440661B1 true EP0440661B1 (fr) 1993-09-29

Family

ID=6365389

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89908824A Expired - Lifetime EP0440661B1 (fr) 1988-10-18 1989-08-01 Filtre passe-bande haute frequence

Country Status (4)

Country Link
US (1) US5136269A (fr)
EP (1) EP0440661B1 (fr)
DE (2) DE3835480A1 (fr)
WO (1) WO1990004861A1 (fr)

Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2246670B (en) * 1990-08-03 1995-04-12 Mohammad Reza Moazzam Microstrip coupled lines filters with improved performance
DE4213195C2 (de) * 1992-04-22 1995-01-19 Rohde & Schwarz Mehrkreisiges Leitungsfilter
EP0600118B1 (fr) * 1992-12-01 1998-05-27 Siemens Aktiengesellschaft Oscillateur à micro-ondes commandé en tension
US5442330A (en) * 1993-12-27 1995-08-15 Motorola, Inc. Coupled line filter with improved out-of-band rejection
KR20010094784A (ko) * 2000-04-06 2001-11-03 윤종용 커패시터 보상회로를 갖는 콤라인 구조의 무선필터
KR100392682B1 (ko) * 2001-02-26 2003-07-28 삼성전자주식회사 주파수 차단회로를 가지는 콤라인 구조의 무선필터 및 그구현 방법
JP2005117433A (ja) * 2003-10-08 2005-04-28 Eudyna Devices Inc フィルタ
JP4230467B2 (ja) * 2005-02-25 2009-02-25 日本電波工業株式会社 コプレーナライン型の共振器を用いた高周波フィルタ
KR100675393B1 (ko) * 2005-02-25 2007-01-29 삼성전자주식회사 집중소자 커패시터와 접지를 이용하여 소형화한 평행결합선로 필터 및 그 제조방법
JP4720907B2 (ja) * 2006-09-28 2011-07-13 株式会社村田製作所 誘電体フィルタ、チップ素子、およびチップ素子製造方法
JP5464864B2 (ja) * 2009-02-25 2014-04-09 京セラ株式会社 フィルタ回路ならびにそれを用いた無線通信モジュールおよび無線通信機器
US9270008B2 (en) * 2011-01-28 2016-02-23 The University Of Electro-Communications Transmission line resonator, bandpass filter using transmission line resonator, multiplexer, balanced-to-unbalanced transformer, power divider, unbalanced-to-balanced transformer, frequency mixer, and balance-type filter
US10249582B2 (en) * 2016-12-19 2019-04-02 Nxp Usa, Inc. Radio frequency (RF) devices with resonant circuits to reduce coupling
US10581132B2 (en) * 2017-05-11 2020-03-03 Eagantu Ltd. Tuneable band pass filter
US10454148B2 (en) 2017-05-11 2019-10-22 Eagantu Ltd. Compact band pass filter

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1358980A (en) * 1971-06-15 1974-07-03 Ferranti Ltd Microwave filters
FR2510326A1 (fr) * 1981-07-24 1983-01-28 Thomson Csf Filtre passe-bande a resonateurs lineaires ouverts a leurs deux extremites
FR2540294B1 (fr) * 1983-01-31 1985-10-04 Thomson Csf Filtre hyperfrequence a resonateurs lineaires
JPS61177001A (ja) * 1985-01-31 1986-08-08 Maspro Denkoh Corp マイクロ波フイルタ
FR2613557A1 (fr) * 1987-03-31 1988-10-07 Thomson Csf Filtre comportant des elements a constantes reparties associant deux types de couplage
FR2613538A1 (fr) * 1987-03-31 1988-10-07 Thomson Csf Filtre hyperfrequence
JPH02146801A (ja) * 1988-11-28 1990-06-06 Fujitsu Ltd 中心周波数可変帯域通過フィルタ

Also Published As

Publication number Publication date
DE3835480A1 (de) 1990-04-19
US5136269A (en) 1992-08-04
EP0440661A1 (fr) 1991-08-14
DE58905789D1 (de) 1993-11-04
WO1990004861A1 (fr) 1990-05-03

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