Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P1/00—Auxiliary devices
  • H01P1/32—Non-reciprocal transmission devices
  • H01P1/38—Circulators
  • H01P1/383—Junction circulators, e.g. Y-circulators
  • H01P1/39—Hollow waveguide circulators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P1/00—Auxiliary devices
  • H01P1/32—Non-reciprocal transmission devices
  • H01P1/38—Circulators
  • H01P1/383—Junction circulators, e.g. Y-circulators

Definitions

• the NRD Guide (Non-Radiative Dielectric waveGuide), which is a millimeter wave integrated circuit, has characteristics such as low loss rate, non-radiativeness, etc.
• the NRD Guide is a structure wherein parallel conducting plates are arranged apart from each other by the distance of a half wavelength of the frequency to be used or less and wherein a dielectric strip having the same height as the gap between the two conducting plates and a certain constant width is inserted in between the two parallel conducting plates.
• a circulator which is the representative nonreciprocal circuit device in the millimeter wave band, is a circuit device indispensable for the application of an isolator, an injection synchronous amplifier, a modulator and so forth.
• the circulator may have some insertion loss of from 4dB to 5dB due to the unnecessary mode (TE, LSE modes) generated between an NRD Guide and a Ferrite resonator. Thus, it may be difficult to get desirable output characteristics. Also, the frequency bandwidth of frequency range having the isolation level over 20dB is at best about 1 GHz. Thus, it is difficult for a modulator to detect desired signal because the range that may include higher order components of signals is narrowed.
• a circulator for the NRD Guide using a permanent magnet as illustrated in Figure 2 has a problem in that it is impossible to maintain the low loss rate, which is the advantage of the NRD Guide. Therefore, such circulator in the related art may not- satlslfy'-tKeerecent needs for communicating a large quantity of information in a broad band of signals.
• the purpose of the present invention is to provide a circulator using a permanent magnet that may maintain the low loss characteristics of the NRD Guide and may have the broadband characteristics at the same time.
• the present invention maintains the low loss characteristics of the NRD Guide by reducing loss through inserting mode suppressors (10,11,12) into the circulator that uses a permanent magnet and the present invention implements that stair form by narrowing the widths of mode suppressors (13, 14, 15) in order to broaden the width of the frequency range that has isolation characteristics over 20dB.
• the first preferred embodiment of the present invention is implemented by mounting a permanent magnet (6) between the upper/lower conducting plates (1,2), composing a Ferrite resonator (illustrated in Figure 5) by assembling a Ferrite (7), a Teflon tube (9) and a Ferrite (8) sequentially along the central axis of the permanent magnet, arranging NRD Guides (3,4,5) around the Ferrite resonator with the gap of 120° from one another as illustrated in Figure 1, and inserting mode suppressors ( 10, 11 , 12) in between the respective NRD Guides (3, 4, 5) and the Ferrite resonator.
• the second preferred embodiment of the present invention is implemented by inserting mode suppressors (13, 14, 15) to compose circulator in the shape of stairs, which are the mode suppressors as inserted in the first preferred embodiment but which have the narrower width than the NRD Guides.
• Fig. 1 illustrates a perspective view of a circulator according to the first preferred embodiment, wherein mode suppressors are inserted in order to minimize the transmission loss of the circulator.
• Fig. 2 illustrates a perspective view of a circulator that has the ordinary structure in the related art.
• Fig. 3 is a schematic diagram that illustrates the basic principle of a circulator that uses NRD Guides.
• Fig. 4 is a schematic diagram that illustrates the modes in a circulator using
• Fig. 5 illustrates a perspective view of a Ferrite resonator that is inserted into the center of a circulator.
• Fig. 6 illustrates a perspective view of an NRD Guide and a disassembled mode suppressor.
• Fig. 7 is a graph that illustrates transmission losses in the cases where mode suppressors are inserted into three terminals of a circulator and where no mode suppressors is inserted.
• Fig. 8 illustrates a perspective view of a circulator for the NRD Guide according to the second preferred embodiment, that may have the broadband characteristics by composing circulator in the shape of stairs through narrowing the width of inserted mode suppressors.
• Fig. 9 is a graph that illustrates the measured impedance that varies corresponding to frequency when the width of mode suppressors is not made narrow for the stair shape.
• Fig I®-- is- a graph that illustrates the measured impedance that varies corresponding to frequency when the circulator has the shape of stairs by narrowing the width of mode suppressors.
• Fig. 11 is a graph that illustrates the transmission losses in the cases where the width of mode suppressors is narrower than the width of the NRD Guides according to the second preferred embodiment and where the width of mode suppressors is not narrowed.
• Mode Suppressor of Isolation Port 12 Mode Suppressor of Output Port
• Figure 1 illustrates a perspective view of the circulator according to the first preferred embodiment of the present invention, wherein mode suppressors (10,11,12) are inserted in between NRD Guides (3,4,5) and a Ferrite resonator that comprises Ferrites (7,8) and a Teflon tube (9).
• mode suppressors (10,11,12) are inserted in between NRD Guides (3,4,5) and a Ferrite resonator that comprises Ferrites (7,8) and a Teflon tube (9).
• PTFE Poly Tetra Fluor Ethylene
• the height of the transmission line which is the same as the gap between the upper and lower conducting plates (1,2), is 2.7mm and the width of transmission line is 2.4mm in the present invention.
• Ferrites (7,8) of the present invention are made by ultrasonic wave processing of the Ferrites of TDK Co., Ltd., that has the permittivity of 15 and is 1800G and whose tangent loss is 0.0008.
• the Ferrites have the circular shape, the diameter of which is 3.37mm and the Ferrites are ground for the proper thickness to be used.
• FIG. 2 Illustrates the structure of a circulator for the NRD Guide in the related art.
• a permanent magnet (6) is inserted in the center of the upper/lower conducting plates (1, 2).
• a Ferrite (7), a Teflon tube (9) and a Ferrite (8) are assembled sequentially along the central axis of the permanent magnet, constructing a Ferrite resonator.
• Figure 5 is a perspective view of the Ferrite resonator.
• NRD Guides (3,4,5) are arranged around the Ferrite resonator with the gap of 120°, making three ports. The role of each port will be explained as illustrated in Figure 3 and Figure 4. Because the unnecessary mode like the LSE mode is generated from a bent part or asymmetrical/discontinuous region of an NRD Guide and affects the circuit, such unnecessary mode may be generated in a nonreciprocal device such as an asymmetrical circulator.
• the LSM mode does not exist in port® (4).
• the magnetic field distribution of the LSE mode forms a loop in the horizontal direction cross section, it is easy for the LSE mode to exist i ⁇ .p' ⁇ yt® -(A)
• the inputted LSM mode is not outputted through port® (4) but outputted through port ⁇ (5) as illustrated in Figure 3.
• the LSE mode is generated in port® (4), causing the insertion loss. Therefore, the insertion loss may be reduced if such unnecessary mode is suppressed.
• mode suppressors (10,11,12) are inserted in between the Ferrite resonator and the NRD Guide of the respective ports as illustrated in Figure 6 according to the present invention.
• the LSM mode is not affected at all by the insertion of a metal strip (18) because the center section of the NRD Guide is made of the electric wall.
• the LSE mode may be removed from the usable frequency range by increasing the cut-off frequency because the electric field of the LSE mode is parallel with the center section. Nonetheless, the TEM mode might be generated against the LSE mode.
• the present invention intends to suppress all of the unnecessary modes by composing the metal strip (18) in the form of a ⁇ /4 choke.
• the mode suppressor is 0.4mm wide at the narrow part and is 2.4mm wide at the wide part.
• the wavelength of the TEM wave, which is plane wave, in the dielectric material is equal because the electromagnetic field is distributed densely within the
• the length of each section of the choke is 0.95mm, that is 1/4 of 3.8mm, the wavelength of the plane wave in the transmission line.
• Figure 7 illustrates the transmission characteristics of Figure 1 and Figure 2.
• the circulator shown in Figure 2 that uses a permanent magnet has the transmission loss of 4dB on the average in the 50GHz range and the circulator according to the first preferred -embodiment shown in ⁇ Figure llmavuses a permanent magnet has the transmission loss of below ldB on the average in the 50GHz range.
• FIG 8 is a perspective view of the second preferred embodiment of the present invention.
• the width of the mode suppressors (10,11,12) of the first preferred embodiment in between the NRD Guides (3, 4, 5) and the Ferrite resonator is narrowed, making the circulator of second preferred embodiment in the form of stairs.
• the Ferrites are 0.342mm thick and the bias magnetic field (the strength of the permanent magnet) is 13200e.
• the reactance component is changed corresponding to the change of center frequency.
• the reactance component of narrowed mode suppressors 13,14,15
• the broadband it is possible to implement the broadband because the impedance matching condition is satisfied over the wide frequency range.
• mode suppressors (13,14,15) are 1.9mm wide, which is narrower than 2.4mm, the width of the NRD Guide.
• the length of mode suppressors is 5.8mm, which is equal to a half wavelength of 50GHz multiplied by an odd number.
• Figure 9 is a graph that illustrates the impedance trajectory corresponding to the center frequency when the width of mode suppressors (10,11,12) is the same as the width of the NRD Guides
• Figure 10 is a graph that illustrates the impedance trajectory corresponding to the center frequency when the width of mode suppressors (13,14,15) is about 1.9mm, which is narrower than the width of NRD Guides.
• Figure 11 illustrates the result of the respective insertion loss/isolation characteristics of the first preferred embodiment and the second preferred embodiment of the present invention. If mode suppressors have the same width as the NRD Guides, the bandwidth that has the isolation characteristics over 20dB is about 1GHz. If mode suppressors are narrower than the NRD Guides as in the circulator using a permanent magnet according to the second preferred embodiment, the bandwidth that has the isolation characteristics over 20dB is over 2GHz and the low loss characteristics of the first preferred embodiment is maintained.
• a circulator that uses an ordinary permanent magnet in the related art, illustrated in Figure 2 has the loss of 4dB due to the asymmetric characteristics.
• the circulator of the first preferred embodiment in which mode Suppressors are inserted may maintain the low loss characteristics of the NRD Guide by suppressing the unnecessary mode caused by the asymmetric characteristics of the circulator using a permanent magnet.
• the circulator of the second preferred embodiment may maintain the low loss characteristics of the NRD Guide by inserting mode suppressors as in the second preferred embodiment ,ah(i,may have ⁇ lfSlb ⁇ dadbandi characteristics at the same time by narrowing the width of the mode suppressors.
• the circulator of the present invention that uses a permanent magnet may remove the heat-emitting symptom generated at the electromagnet used in the related art, eliminate the need for consumption of the electricity and make it unnecessary to use the electric source circuit added when the electromagnet is used.
• the circulator of the present invention that uses a permanent magnet may accomplish the desired output characteristics because it reduces the insertion loss of electric waves by inserting mode suppressors in between the respective NRD Guides and the Ferrite resonator.
• the present invention may broaden the bandwidth of the usable frequency by narrowing the width of the mode suppressors so that the mode suppressors become narrower than the NRD Guides.
• the circulator using the permanent magnet may attain the advantages as a nonreciprocal device of a modulator, amplifier or etc. because the circulator of the present invention using the permanent magnet has the superior characteristics of low loss and broadband.

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• Non-Reversible Transmitting Devices (AREA)
• Control Of Motors That Do Not Use Commutators (AREA)
• Waveguides (AREA)

Applications Claiming Priority (2)

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Citations (3)

• 2001
  • 2001-02-20 KR KR1020010008330A patent/KR100358975B1/ko not_active IP Right Cessation
• 2002
  • 2002-01-28 CN CNA028049608A patent/CN1491449A/zh active Pending
  • 2002-01-28 WO PCT/KR2002/000123 patent/WO2002067360A1/en not_active Application Discontinuation

Patent Citations (3)

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