EP2515372A1 - Bandpassfilter - Google Patents

Bandpassfilter Download PDF

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Publication number
EP2515372A1
EP2515372A1 EP11163239A EP11163239A EP2515372A1 EP 2515372 A1 EP2515372 A1 EP 2515372A1 EP 11163239 A EP11163239 A EP 11163239A EP 11163239 A EP11163239 A EP 11163239A EP 2515372 A1 EP2515372 A1 EP 2515372A1
Authority
EP
European Patent Office
Prior art keywords
resonator
band
pass filter
quarter wavelength
resonators
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Withdrawn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
EP11163239A
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English (en)
French (fr)
Inventor
Ping Chin Tseng
Hong Ru Suchen
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.)
Microelectronics Technology Inc
Original Assignee
Microelectronics Technology Inc
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 Microelectronics Technology Inc filed Critical Microelectronics Technology Inc
Priority to EP11163239A priority Critical patent/EP2515372A1/de
Publication of EP2515372A1 publication Critical patent/EP2515372A1/de
Withdrawn legal-status Critical Current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
    • H01P1/20372—Hairpin resonators

Definitions

  • the present invention relates to filter design, and more particularly, to band-pass filter design.
  • a receiver 100 receives a radio frequency (RF) signal with frequency f R
  • the received RF signal is amplified by an RF antenna 101.
  • a mixer 102 and a local oscillator (LO) 103 are utilized to shift the frequency of the received RF signal to an intermediate frequency f I for the subsequent signal processing.
  • the LO 103 is configured to provide an LO signal with an adjustable frequency f O .
  • the mixer 102 is configured to perform a multiplying operation for the received RF signal and the LO signal to produce new signals of beat frequencies of f R + f O and f R - f O .
  • the signal of frequency f R - f O is the desired signal, wherein the frequency f R - f O equals the intermediate frequency f I , and the signal with frequency f R + f O is the unwanted signal.
  • the RF antenna 101 may also receive image signals with image frequency f W , wherein the image frequency f W equals f O - f I . Accordingly, after the operation of the mixer 102, the image signals are also shifted to the intermediate frequency f I since new signals of beat frequencies of f O + f W and f O - f W are also produced, wherein the frequency of f O - f W equals the intermediate frequency f I . As a result, the image signals will cause interferences with the received RF signal. Therefore, a band-pass filter 104 is often required to eliminate the image signals, as shown in FIG. 1 .
  • FIG. 2 One conventional band-pass filter structure is shown in FIG. 2 .
  • the band-pass filter 200 uses a hairpin structure.
  • FIG. 3 Another conventional band-pass filter structure is shown in FIG. 3 .
  • the band-pass filter 300 uses an inter-digital structure.
  • FIG. 4 shows the frequency responses of the band-pass filters 200 and 300.
  • the hairpin band-pass filter 200 exhibits a steeper slope at the lower side of the pass band, i.e. the frequency band of the image signal, and a smaller gain at the pass band compared to the inter-digital band-pass filter 300. Accordingly, the hairpin band-pass filter 200 has a better image rejection capability at the lower side of the passband but a poor insertion loss compared to the inter-digital band-pass filter 300.
  • the inter-digital band-pass filter 300 has a poor image rejection capability but a better insertion loss compared to the hairpin band-pass filter 200.
  • the hairpin band-pass filter 200 requires more layout area.
  • the band-pass filter comprises a first resonator, a second resonator and a third resonator.
  • the second resonator is magnetically coupled to the first resonator.
  • the third resonator is magnetically coupled to the second resonator and is electrically coupled to the first resonator.
  • the first resonator is a quarter wavelength resonator
  • the second resonator is a half wavelength resonator
  • the third resonator is a quarter wavelength resonator.
  • the band-pass filter according to another embodiment of the present invention comprises a plurality of half wavelength resonators and a plurality of quarter wavelength resonators.
  • the plurality of half wavelength resonators and the plurality of quarter wavelength resonators are arranged along a first direction in an interleaved manner, and each of the two ends of the band-pass filter is arranged with a quarter wavelength resonator.
  • FIG. 5 shows a band-pass filter structure according to an embodiment of the present invention.
  • the band-pass filter 500 comprises a first resonator 501, a second resonator 502 and a third resonator 503.
  • the first resonator 501, the second resonator 502 and the third resonator 503 are arranged along the X-direction with the second resonator 502 sandwiched between the first resonator 501 and the third resonator 503.
  • the first resonator 501 and the third resonator 503 are both quarter wavelength resonators.
  • the lengths of the first resonator 501 and the third resonator 503 are a quarter of the wavelength of the electromagnetic wave received by the band-pass filter 500.
  • both the first resonator 501 and the third resonator 503 are in a long strip shape extending along the Y-direction.
  • both the first resonator 501 and the third resonator 503 have one end connected to a ground line 510.
  • the second resonator 502 is a half wavelength resonator. That is, the length of the second resonator 502 is half of the wavelength of the electromagnetic wave received by the band-pass filter 500.
  • the second resonator 502 is in a U shape with the opening facing the ground line 510.
  • FIG. 6 shows a coupling diagram of the band-pass filter 500 shown in FIG. 5 .
  • the magnetic coupling between the first resonator 501 and the second resonator 502 is strong. Accordingly, the coupling between the first resonator 501 and the second resonator 502 is represented by an inductance L1.
  • the magnetic coupling between the second resonator 502 and the third resonator 503 is also strong. Therefore, the coupling between the second resonator 502 and the third resonator 503 is represented by an inductance L2.
  • the magnetic coupling between the first resonator 501 and the third resonator 503 is weak and the electric coupling dominates the coupling between both resonators. Accordingly, the first resonator 501 and the third resonator 503 is represented by a conductance C1.
  • the phase of the first path which is from the first resonator 501 to the third resonator 503 passing through the second resonator 502, is -90 degrees.
  • the phase of the second path which is from the first resonator 501 directly to the third resonator 503, is 90 degrees. That is, when the band-pass filter 500 is operated below resonance, the first path and the second path are out of phase, which accordingly introduces a transmission zero at the lower side of the pass band of the band-pass filter 500.
  • FIG. 7 shows the frequency responses of the band-pass filters 200, 300 and 500.
  • the frequency response of the band-pass filter 500 has a transmission zero at the lower side of the pass band, which produces a steep slope at the lower side of the pass band. Accordingly, the band-pass filter 500 has a great image rejection capability.
  • the band-pass filter 500 also exhibits a small insertion loss.
  • FIG. 5 shows a three-order band-pass filter 500.
  • the present invention is not limited to a three-order band-pass filter, and should cover any other higher-order band-pass filters with the same structure concept.
  • FIG. 8 shows a band-pass filter structure according to another embodiment of the present invention.
  • the band-pass filter 800 comprises three quarter wavelength resonators 801, 802 and 803 and two half wavelength resonators 804 and 805.
  • the three quarter wavelength resonators 801, 802 and 803 and the two half wavelength resonators 804 and 805 are arranged along the X-direction in an interleaved manner with each of the two ends of the band-pass filter 800 arranged with a quarter wavelength resonator 801 and 803 respectively.
  • the band-pass filter 800 is a five-order band-pass filter.
  • FIG. 9 shows a band-pass filter structure according to yet another embodiment of the present invention.
  • the band-pass filter 900 comprises four quarter wavelength resonators 901, 902, 903 and 904 and three half wavelength resonators 905, 906 and 907.
  • the four quarter wavelength resonators 901, 902, 903 and 904 and the three half wavelength resonators 905, 906 and 907 are arranged along the X-direction in an interleaved manner with each of the two ends of the band-pass filter 900 arranged with a quarter wavelength resonator 901 and 904 respectively.
  • the band-pass filter 900 is a seven-order band-pass filter.
  • the present invention provides band-pass filters exhibiting great image rejection capability and small insertion loss.
  • the layout areas of the band-pass filters provided by the present invention can meet the requirement of the modem filter design. Therefore, the band-pass filters provided by the present invention are suitable for the low noise block specified in North American standard, i.e. the frequency band between 12.2GHz and 12.7GHz, and the low noise block specified in European standard, i.e. the frequency band between 10.7GHz and 12.75GHz.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Control Of Motors That Do Not Use Commutators (AREA)
EP11163239A 2011-04-20 2011-04-20 Bandpassfilter Withdrawn EP2515372A1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP11163239A EP2515372A1 (de) 2011-04-20 2011-04-20 Bandpassfilter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP11163239A EP2515372A1 (de) 2011-04-20 2011-04-20 Bandpassfilter

Publications (1)

Publication Number Publication Date
EP2515372A1 true EP2515372A1 (de) 2012-10-24

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP11163239A Withdrawn EP2515372A1 (de) 2011-04-20 2011-04-20 Bandpassfilter

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EP (1) EP2515372A1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2672821C1 (ru) * 2017-10-30 2018-11-19 Федеральное государственное бюджетное образовательное учреждение высшего образования "Сибирский государственный университет науки и технологий имени академика М.Ф. Решетнева" (СибГУ им. М.Ф. Решетнева) Полосно-пропускающий фильтр
CN110034364A (zh) * 2019-04-30 2019-07-19 天津大学 一种超低插入损耗的陶瓷基交叉耦合发夹型滤波器

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000357902A (ja) * 1999-06-14 2000-12-26 Murata Mfg Co Ltd 平面フィルタおよびそれを用いたデュプレクサおよびそれらを用いた高周波モジュールおよびそれを用いた通信装置
US20080224800A1 (en) * 2006-09-28 2008-09-18 Murata Manufacturing Co., Ltd. Dielectric Filter, Chip Device and Method of Manufacturing the Chip Device
US20100141356A1 (en) * 2008-12-09 2010-06-10 Electronics And Telecommunications Research Institute Coupled line filter and arraying method thereof
WO2010137398A1 (ja) * 2009-05-26 2010-12-02 株式会社村田製作所 ストリップラインフィルタ

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000357902A (ja) * 1999-06-14 2000-12-26 Murata Mfg Co Ltd 平面フィルタおよびそれを用いたデュプレクサおよびそれらを用いた高周波モジュールおよびそれを用いた通信装置
US20080224800A1 (en) * 2006-09-28 2008-09-18 Murata Manufacturing Co., Ltd. Dielectric Filter, Chip Device and Method of Manufacturing the Chip Device
US20100141356A1 (en) * 2008-12-09 2010-06-10 Electronics And Telecommunications Research Institute Coupled line filter and arraying method thereof
WO2010137398A1 (ja) * 2009-05-26 2010-12-02 株式会社村田製作所 ストリップラインフィルタ

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
CHENG-CHUNG CHEN ET AL: "A novel coupling structure suitable for cross-coupled filters with folded quarter-wave resonators", IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS, IEEE SERVICE CENTER, NEW YORK, NY, US, vol. 13, no. 12, 1 December 2003 (2003-12-01), pages 517 - 519, XP011106053, ISSN: 1531-1309, DOI: 10.1109/LMWC.2003.819957 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2672821C1 (ru) * 2017-10-30 2018-11-19 Федеральное государственное бюджетное образовательное учреждение высшего образования "Сибирский государственный университет науки и технологий имени академика М.Ф. Решетнева" (СибГУ им. М.Ф. Решетнева) Полосно-пропускающий фильтр
CN110034364A (zh) * 2019-04-30 2019-07-19 天津大学 一种超低插入损耗的陶瓷基交叉耦合发夹型滤波器

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