EP1296406A1 - Suppression en mode parasite de type seconde harmonique en résonateurs à demi-ondes appliquée à des structures de filtre à micro-ondes - Google Patents

Suppression en mode parasite de type seconde harmonique en résonateurs à demi-ondes appliquée à des structures de filtre à micro-ondes Download PDF

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Publication number
EP1296406A1
EP1296406A1 EP01402437A EP01402437A EP1296406A1 EP 1296406 A1 EP1296406 A1 EP 1296406A1 EP 01402437 A EP01402437 A EP 01402437A EP 01402437 A EP01402437 A EP 01402437A EP 1296406 A1 EP1296406 A1 EP 1296406A1
Authority
EP
European Patent Office
Prior art keywords
microstrip conductor
conductor
length microstrip
forcing
low voltage
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.)
Withdrawn
Application number
EP01402437A
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German (de)
English (en)
Inventor
Umberto Lodi
Alberto Villa
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.)
Alcatel CIT SA
Alcatel Lucent SAS
Original Assignee
Alcatel CIT SA
Alcatel SA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Alcatel CIT SA, Alcatel SA filed Critical Alcatel CIT SA
Priority to EP01402437A priority Critical patent/EP1296406A1/fr
Publication of EP1296406A1 publication Critical patent/EP1296406A1/fr
Withdrawn legal-status Critical Current

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    • 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
    • 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
    • H01P1/20372—Hairpin resonators
    • 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
    • H01P1/212—Frequency-selective devices, e.g. filters suppressing or attenuating harmonic frequencies
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P7/00—Resonators of the waveguide type
    • H01P7/08—Strip line resonators
    • H01P7/082—Microstripline resonators

Definitions

  • the present invention relates to resonators and a method for suppressing second harmonic spurious mode in half-wave resonators.
  • the present invention also relates to microwave band filtering structures and a method for microwave band filtering signals.
  • Electromagnetic resonators are often used in filters in order to pass or reject certain signal frequencies. To optimize filter performance, the resonators should have a minimum of signal loss in the passed frequency range.
  • Resonators like those employed for instance in microwave filters (edge-coupled, hairpin, etc.) give rise to spurious responses at frequencies well above the normally operating ones. These responses can take place with little attenuation, so that undesired signals (like for instance second and third harmonics) may pass through the filter with an excessive level, which is often unacceptable to the rest of RF system.
  • the first spurious mode occurs typically at frequencies which are twice the bandpass ones, namely when the resonator length is equal to an entire wavelength, and the next spurious mode takes place (with lower theoretical transmission loss) at three times the first resonance.
  • a typical solution for solving the above problem comprises the step of placing an extra filter (typically a lowpass one) in series with the bandpass structure, the extra filter being designed in order to avoid the above "reentrance” problems, which attenuates the spurious responses of the bandpass filter.
  • an extra filter typically a lowpass one
  • the extra filter arrangement is rather effective but it requires an extra amount of space. Furthermore, the extra filter will dissipate some RF energy.
  • the main object of the present invention is providing a resonator arrangement wherein second harmonic spurious mode is suppressed, in particular a resonator arrangement to be used in microwave filtering structures.
  • a further object of the present invention is providing a method for suppressing second harmonic spurious mode in half-wave resonators, in particular in half-wave resonators to be used in microwave filtering structures.
  • a still further object of the present invention is providing a microwave band filter wherein second harmonic spurious mode is suppressed.
  • a still further object of the present invention is providing a method for microwave band filtering signals.
  • the basic idea of the present invention mainly oriented to microstrip or stripline technologies, consists in rejecting the second resonant response by "forcing" a low voltage in the middle of the half wavelength resonator, where a voltage null would occur under normal operating conditions.
  • a filter for the microwave band consists of a dielectric substrate 26, a ground conductor plane 28 on the back side of the substrate 26 and a microstrip transmission line conductor formed on the front surface of the dielectric substrate, the transmission line conductor comprising an input IN and an output OUT transmission line conductors which are connected to an external circuit and a plurality of resonators.
  • Each resonator comprises a ⁇ /2-length microstrip conductor (where ⁇ is the line wavelength correspondent to the fundamental resonance frequency, f 0 ).
  • the ⁇ /2-length microstrip conductors are of hairpin type or of an edge-coupled (linear) type.
  • Fig. 1 shows a ⁇ /2 microstrip transmission line 10 and desired (first) resonance mode (bold line 14). Second and third resonance modes are also indicated by respective dotted lines 16, 18.
  • Fig. 2 shows a third order hairpin bandpass filter layout according to the state of the art with an input transmission line conductor IN and an output transmission line conductor OUT.
  • three U shaped microstrip conductors 101, 102, 103 are arranged side-by-side. It should be noticed that the layout of Fig. 2 (wherein the resonators 101, 102, 103 alternate, i.e. neighboring resonators face opposite directions) is purely exemplificative. This means that the basic idea of the present invention equally applies to resonators arranged in a hairpin-comb configuration.
  • the basic idea of the present invention consists in rejecting the second resonant response by "forcing" a low voltage in the middle of the half wavelength resonator, where a voltage null 12 would occur under normal operating conditions.
  • the basic idea consists in creating a low impedance path between the half-wave resonator centre and the ground in order to attenuate the second harmonic spourious mode without influencing the main mode.
  • the low impedance path can be created by connecting a resistor (R1, R2, R3) in the middle of each half wavelength resonators 101, 102, 103, see for instance Figures 3 and 6.
  • Fig. 6 shows a third order edge-coupled filter layout with second resonance suppressing resistors according to the present invention.
  • a low RF voltage can be easily guaranteed by placing low impedance, wide-band components (like for instance 100 ⁇ SMD resistors in 0603 size) between the ground plane and the center of the half-wave resonating lines of the filter.
  • This extra component will not seriously perturb the normal operation of the filter (because it is positioned in a voltage node), but on the other hand it will strongly attenuate the second resonance mode of the transmission line, when the center point would otherwise be subject to voltage peaks instead.
  • the resistors can be mounted on the same side as the filter transmission lines (the grounding can take place by means of appropriate via holes).
  • the via holes can be placed in the middle of the half-wave lines, and the resistors mounted on the ground plane side (see Fig. 8).
  • the present invention has been computer simulated and the simulation results are shown in Fig. 4 (for an hairpin filter) and in Fig. 7 (for an edge-coupled filter), respectively.
  • Fig. 4 shows a comparison between spurious responses of a 10 GHz hairpin filter according to the state of the art (dotted line 20) and according to the present invention (solid line 22).
  • the graph shows that below 13000 MHz the spurious responses are the same but, starting from a frequency around 13000 MHz, the spurious responses become significantly lower than the prior art.
  • Fig. 8 shows a possible implementation of the present invention in case of microstrip edge-coupled structure.
  • via holes 24 are made in the substrate 26 and the resistors R are arranged in the ground plane 26 which is opposite to the ⁇ /2 resonating line.
  • the second harmonic response i.e. the closest one to the desired passband
  • the second harmonic response is strongly attenuated without the need for an extra lowpass filter, avoiding in this way the manufacturing and test of a second filter, and saving also some (often precious) space.
  • the third resonance mode (third harmonic response) is not affected (but as already mentioned, this will typically take place at frequencies that are so high, that in many cases it can be neglected by the system.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Control Of Motors That Do Not Use Commutators (AREA)
EP01402437A 2001-09-21 2001-09-21 Suppression en mode parasite de type seconde harmonique en résonateurs à demi-ondes appliquée à des structures de filtre à micro-ondes Withdrawn EP1296406A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP01402437A EP1296406A1 (fr) 2001-09-21 2001-09-21 Suppression en mode parasite de type seconde harmonique en résonateurs à demi-ondes appliquée à des structures de filtre à micro-ondes

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP01402437A EP1296406A1 (fr) 2001-09-21 2001-09-21 Suppression en mode parasite de type seconde harmonique en résonateurs à demi-ondes appliquée à des structures de filtre à micro-ondes

Publications (1)

Publication Number Publication Date
EP1296406A1 true EP1296406A1 (fr) 2003-03-26

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EP01402437A Withdrawn EP1296406A1 (fr) 2001-09-21 2001-09-21 Suppression en mode parasite de type seconde harmonique en résonateurs à demi-ondes appliquée à des structures de filtre à micro-ondes

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EP (1) EP1296406A1 (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101599568B (zh) * 2009-07-09 2013-07-10 北京大学 一种可抑制二次谐波的带通滤波器
CN104091980A (zh) * 2014-06-20 2014-10-08 华南理工大学 一种宽阻带抑制的带通滤波器
CN109149027A (zh) * 2017-06-19 2019-01-04 北京握奇智能科技有限公司 一种微带线带通滤波器
EP3439110A4 (fr) * 2016-08-09 2019-12-11 Tongyu Communication Inc. Réseau d'alimentation de filtre et antenne de station de base
WO2020057722A1 (fr) * 2018-09-17 2020-03-26 European Space Agency Filtre passe-bande radio-fréquence
CN110931926A (zh) * 2019-11-12 2020-03-27 郴州世通科技有限公司 微带线滤波器
CN112072238A (zh) * 2020-07-31 2020-12-11 南京邮电大学 一种发夹型带通滤波器

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6360604A (ja) * 1986-08-29 1988-03-16 Sharp Corp 帯域通過フイルタ
JPH03178201A (ja) * 1989-12-07 1991-08-02 Sharp Corp マイクロ波バンドパスフィルタ
US5066933A (en) * 1989-08-30 1991-11-19 Kyocera Corporation Band-pass filter
JP2000174554A (ja) * 1998-12-01 2000-06-23 Nec Corp 電圧制御型発振器

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6360604A (ja) * 1986-08-29 1988-03-16 Sharp Corp 帯域通過フイルタ
US5066933A (en) * 1989-08-30 1991-11-19 Kyocera Corporation Band-pass filter
JPH03178201A (ja) * 1989-12-07 1991-08-02 Sharp Corp マイクロ波バンドパスフィルタ
JP2000174554A (ja) * 1998-12-01 2000-06-23 Nec Corp 電圧制御型発振器

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 012, no. 285 (E - 642) 4 August 1988 (1988-08-04) *
PATENT ABSTRACTS OF JAPAN vol. 015, no. 423 (E - 1127) 28 October 1991 (1991-10-28) *
PATENT ABSTRACTS OF JAPAN vol. 2000, no. 09 13 October 2000 (2000-10-13) *

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101599568B (zh) * 2009-07-09 2013-07-10 北京大学 一种可抑制二次谐波的带通滤波器
CN104091980A (zh) * 2014-06-20 2014-10-08 华南理工大学 一种宽阻带抑制的带通滤波器
CN104091980B (zh) * 2014-06-20 2017-01-04 华南理工大学 一种宽阻带抑制的带通滤波器
EP3439110A4 (fr) * 2016-08-09 2019-12-11 Tongyu Communication Inc. Réseau d'alimentation de filtre et antenne de station de base
CN109149027A (zh) * 2017-06-19 2019-01-04 北京握奇智能科技有限公司 一种微带线带通滤波器
WO2020057722A1 (fr) * 2018-09-17 2020-03-26 European Space Agency Filtre passe-bande radio-fréquence
US20210376436A1 (en) * 2018-09-17 2021-12-02 European Space Agency A radio frequency pass-band filter
CN110931926A (zh) * 2019-11-12 2020-03-27 郴州世通科技有限公司 微带线滤波器
CN110931926B (zh) * 2019-11-12 2022-01-07 郴州世通科技有限公司 微带线滤波器
CN112072238A (zh) * 2020-07-31 2020-12-11 南京邮电大学 一种发夹型带通滤波器

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