• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
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    • 专利摘要:
    PURPOSE: A dielectric body filter, a dielectric body duplexer, and a communicating device are provided to manufacture a dielectric body which has a good temperature characteristics. CONSTITUTION: A dielectric body filter has a damping bandwidth, which is located in the vicinity of a passing bandwidth. A limit frequency position is disposed in the vicinity of the shoulder portion of a wave, which represents the passing characteristics in which the insertion loss is increased from the passing bandwidth to the damping bandwidth. The shoulder portion is moved towards the damping bandwidth according to the rising and lowering of the temperature. According to the dielectric body filter, the dielectric body duplexer, and the communicating device, a dielectric body that has good temperature characteristics can be manufactured.
    公开号:KR20000057794A
    申请号:KR1020000003153
    申请日:2000-01-24
    公开日:2000-09-25
    发明作者:다다히토시；가토히데유키；히로시마모토하루
    申请人:무라타 야스타카；가부시키가이샤 무라타 세이사쿠쇼；
    IPC主号:
    专利说明:

    Dielectric filter, dielectric duplexer and communication apparatus
    The present invention relates to a dielectric filter using a dielectric material in the resonator portion, a dielectric duplexer and a communication device using the same.
    In general, for example, when a plurality of dielectric resonators are arranged in a dielectric block to form a dielectric duplexer, a plurality of resonant line holes are arranged in the dielectric block, and a resonance line is formed on the inner surface of the hole, thereby providing a signal of a transmission band. The transmit filter portion is allowed to pass through and the signal of the reception band is attenuated, and the receive filter portion is allowed to penetrate the signal of the reception band and the signal of the transmission band is attenuated, respectively.
    In the case where the transmission filter and the reception filter are each band-shaped filters, the pass characteristic of each filter is shown in Figs. 14A and 14B. In this case, the symbol Tx represents the pass characteristic of the transmission filter, and the symbol Rx represents the pass characteristic of the reception filter. As shown by the hatched portions of F1, F2, F3, and F4 in this figure, the characteristics of the transmission filter define the maximum insertion loss (F1) in the transmission band and the minimum insertion loss (F2) in the reception band, and receive The characteristics of the filter define the maximum insertion loss (F2) in the reception band and the minimum insertion loss (F4) in the transmission band. The transmission filter and the reception filter are designed to satisfy these conditions.
    However, the pass characteristics shown in FIGS. 14A and 14B are at specific temperatures. In general, in the dielectric filter and the dielectric duplexer, the higher the temperature, the worse the no-load Q factor Qo of the resonator. This is due to the temperature characteristic of the electrode material. For example, in the case of silver or copper, the conductivity decreases by about 2% with every 10 ° C. rise in temperature. The conductivity drop of the electrode directly causes Qo to deteriorate. As a result, the higher the temperature is, the worse the insertion loss of the filter is.
    In general, the characteristics of the pass band are defined as areas defining the maximum insertion loss and its frequency range (from one limit frequency to the other limit frequency), and the shoulder portions (both shoulder portions) of the pass band characteristic ( Portions A and B) shown in FIGS. 14A and 14B are close to the ends of the region. In addition, in the case of a duplexer, since the transmit and receive bands are generally close to each other, the shoulder portion in the range from the pass band to its reduced band is close to the attenuation band in the region defining the maximum insertion loss and its frequency range. It is closest to the side end part (hereafter, the part which shows a maximum insertion loss and a frequency range is called a "limit point").
    For example, the filter (transmission filter) on the low frequency side of the pass band has a threshold on the high frequency side of the pass band, as shown by part A in FIG. 14A. The filter (receive filter) on the high frequency side of the pass band has a threshold at the low frequency side of the pass band, as shown by the B portion.
    In this case, when the temperature of the dielectric duplexer rises, the Qo of the resonator deteriorates due to the reasons described above, and the insertion loss increases as indicated by the dotted line in Fig. 14A. In addition, when exceeding a predetermined temperature or more, the high frequency side shoulder portion of the transmission characteristic of the transmission filter and the low frequency side shoulder portion of the passage characteristic of the reception filter exceed the maximum insertion loss at each limit point.
    Although the example shown in Fig. 14A shows the case where the dielectric constant-temperature characteristic of the dielectric material is constant (the dielectric constant does not change regardless of temperature change), when the dielectric material has the dielectric constant-temperature characteristic, it is shown in Fig. 14B. As described above, the pass characteristic moves to the high frequency side or the low frequency side according to the slope of this characteristic. For example, in the case where the dielectric constant decreases as the temperature increases and the resonance frequency increases, the passage characteristic as indicated by the dotted line in FIG. 14B is exhibited. In this case, the shoulder portion of the pass characteristic of the reception filter having the attenuation band on the low frequency side exceeds the maximum insertion loss at the threshold as shown by the B portion. In addition, as shown in FIG. 14A, the waveform of the passage characteristic not only moves downward but also moves obliquely downward in the drawing. Therefore, the above-mentioned problems occur even at a relatively low temperature.
    The above problems not only occur in the case of the dielectric duplexer, but also similarly in the case of a single dielectric filter having a threshold near the shoulder portion where the insertion loss increases in the region from the pass band to the attenuation band.
    In order to overcome the above-mentioned problems, preferred embodiments of the present invention provide a dielectric filter, a dielectric duplexer, and a communication device using the same, which exhibits excellent characteristics over a wide temperature range by improving the deterioration of insertion loss characteristics with respect to temperature changes. . In the present invention, even if a temperature change occurs in the dielectric filter or dielectric duplexer, the waveform representing the pass characteristic of the filter or duplexer is shifted so as not to exceed the threshold determined by the maximum insertion loss and its limit frequency.
    1A, 1B, 1C and 1D are projection views of a dielectric filter according to a first embodiment of the present invention.
    2 is an equivalent circuit diagram of a dielectric filter.
    3A and 3B are graphs showing passage characteristics of the dielectric filter.
    4 is a graph illustrating an example of frequency-temperature change with difference in dielectric material.
    5A, 5B, 5C and 5D are projection views of a dielectric filter according to a second embodiment of the present invention.
    6 is an equivalent circuit diagram of a dielectric filter.
    7 is a graph showing the pass characteristics of a dielectric filter.
    8 is an equivalent circuit diagram of a dielectric filter according to a third embodiment of the present invention.
    9 is a graph showing the pass characteristics of a dielectric filter.
    10A, 10B, 10C and 10D are projection views of a dielectric duplexer according to a fourth embodiment of the present invention.
    11 is an equivalent circuit diagram of a dielectric duplexer.
    12A and 12B are graphs showing passage characteristics of the dielectric duplexer.
    Fig. 13 is a block diagram showing the construction of a communication device according to a fifth embodiment of the present invention.
    14A and 14B are graphs showing the passage characteristics of a conventional dielectric duplexer.
    <Brief description of the main parts of the drawing>
    1 ... dielectric block 2 ... resonant line hole
    3 ... I / O line hole
    4, 5 ... resonant line holes 7, 8, 9 ... input / output terminals
    10 ... grounding electrode 12 ... resonant line
    13 ... I / O line 15 ... Resonant line
    One preferred embodiment of the present invention has an attenuation band proximate to the pass band and has a maximum insertion loss defined in the shoulder portion of the waveform which exhibits an increase in insertion loss in the region from the pass band to the attenuation band. It provides a dielectric filter in which the limit frequencies of are arranged in close proximity. In this dielectric filter, the temperature characteristic of the dielectric material is determined so that the shoulder portion moves in the direction of the attenuation band in response to the temperature rise and the temperature decrease. With such a configuration, even if the pass characteristic of the filter changes with temperature rise and temperature drop, the shoulder portion is moved to avoid the threshold in the region from the pass band to the attenuation band, so that a specific characteristic can be maintained.
    The above-described dielectric filter may be composed of a plurality of dielectric resonators, and at least one of the dielectric resonators becomes a trap resonator forming an attenuation pole in the region from the shoulder portion to the attenuation band. In addition, the temperature characteristic of the dielectric material is determined such that the change in the resonant frequency with respect to the temperature change in the trap resonator is smaller than the change in the resonant frequency with the temperature change in the other dielectric resonator. With such a configuration, the attenuation characteristic near the attenuation pole is constant irrespective of temperature change, so that a specific attenuation characteristic can be maintained.
    In addition, the plurality of dielectric resonators may be integrally molded or integrally fired as a single dielectric block. In the case of constructing the dielectric filter by discontinuously combining the dielectric resonators, the difference in the temperature characteristics of the dielectric material cannot be discriminated from the appearance, so even if there is a problem that a typology occurs in the above configuration, the present invention makes such a problem. You can solve the problem.
    The above-described dielectric filter may be a band pass filter formed of a plurality of dielectric resonators in which a pass band is used as a range of resonant frequencies. With this configuration, the insertion loss of the pass band is further reduced, and the insertion loss in the shoulder portion of the pass band adjacent to the attenuation band can be kept at a low level over a wide temperature range.
    The dielectric filter may be a bandpass filter formed of a plurality of dielectric resonators whose attenuation bands are used as a range of resonance frequencies. With this configuration, a large amount of attenuation can be obtained in the attenuation band, and at the same time, the insertion loss can be kept at a low level over a wide temperature range in the shoulder portion of the pass band adjacent to the attenuation band.
    Another preferred embodiment of the present invention provides a dielectric duplexer comprising two of the aforementioned dielectric filters. One of the two filters is a dielectric filter in which the low frequency band of the filter is an attenuation band and the high frequency band of the filter is a pass band; Another filter is a dielectric filter in which the low frequency band of the filter is a pass band and the high frequency band of the filter is an attenuation band. With this configuration, in both filters, the shoulder portion of the pass characteristic in the region from the pass band to the attenuation band does not exceed the maximum insertion loss over a wide temperature range, thereby maintaining the function of the duplexer. In addition, in this dielectric duplexer, when the two dielectric filters are integrally molded or integrally fired by a single dielectric block, the above-described typographical error in the above configuration does not occur.
    Another preferred embodiment of the present invention provides a communication apparatus in which one of the above-described dielectric filter and the above-described dielectric duplexer is configured in the high frequency circuit section. With this configuration, a communication device capable of maintaining a specific signal processing function of the high frequency circuit portion over a wide temperature change is obtained.
    Other features and advantages of the invention will be apparent from the following description of the invention with reference to the accompanying drawings.
    The configuration of the dielectric filter according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 4.
    1A-1D are projection views of a dielectric filter. FIG. 1A shows a plan view, FIG. 1B shows a front view, FIG. 1C shows a bottom view, and FIG. 1D shows a right side. When the dielectric filter is mounted as a component on a printed circuit board, the front surface shown in FIG. 1B becomes a mounting surface with respect to the printed circuit board.
    This dielectric filter is constructed by forming various holes and electrodes for the rectangular parallelepiped dielectric block 1. More specifically, reference numerals 2a, 2b, and 2c denote resonant line holes, and resonant line 12a, 12b, and 12c are formed on the inner surface thereof. Reference numerals 3a and 3b denote holes for input / output coupling lines, and input / output coupling lines 13a and 13b are formed on the inner surface thereof. These holes are stepped holes in which the inner diameter of the through holes changes at a constant rate. On the outer surface of the dielectric block 1, continuous input / output terminals 7, 8 are formed from the input / output coupling lines 13a and 13b, respectively, and ground electrodes 10 are formed on approximately the front surface (side 6) except these input / output terminals. In addition, in the resonant lines 12a, 12b, and 12c, an electrode non-forming portion (conductor non-forming portion) indicated by " g " is formed near the end of the large side of the inner diameter of the step hole, and stray capacitance Cs is generated in this portion.
    The operation of the dielectric filter having the above-described configuration will be described. First, the resonant lines 12a, 12b, and 12c formed in the resonant line holes 2a, 2b, and 2c each have capacitive coupling. In other words, the resonant lines 12a, 12b, and 12c are combined by a combination of the coupling (inductive coupling) of the comb-shaped line formed by the above Cs and the capacitive coupling formed by the step hole. In this case, since the relationship of inductive coupling &lt; capacitive coupling is provided, the resonant lines 12a, 12b and 12c are capacitively coupled as a whole. An interdigital coupling is formed between the resonance line 12a and the input / output coupling line 13a and between the resonance line 12c and the input / output coupling line 13b. With this configuration, the component between the input and output terminals 7, 8 acts as a band pass filter.
    2 is an equivalent circuit diagram of the dielectric filter. In Fig. 2, the symbols Za, Zb and Zc represent the impedances generated by the resonant lines 12a, 12b and 12c shown in Fig. 1, and the symbols Zi and Zo are generated by the input / output coupling lines 13a and 13b shown in Fig. 1. Represents the impedance. In addition, the symbol Zia represents the impedance generated by the mutual capacitance generated between the resonance line 12a and the input / output coupling line 13a, and the symbol Zco is generated by the mutual capacitance generated between the resonance line 12c and the input / output coupling line 13b. Represents the impedance. The symbol Zab represents the impedance generated by the mutual capacitance generated between the resonance line 12a and the resonance line 12b, and the symbol Zbc represents the impedance generated by the mutual capacitance generated between the resonance line 12b and the resonance line 12c. Indicates.
    3A and 3B show graphs showing pass characteristics of the dielectric filter. In this example, the capacitive coupling forms an attenuation pole on the low frequency side of the pass band, and acquires a sharp attenuation characteristic in the region from the pass band to the attenuation band on the low frequency side thereof. In this figure, the hatched portion shows the maximum insertion loss and its frequency range. At normal temperatures, the shoulder portion of the waveform exhibiting pass characteristics is close to the threshold in the region from the pass band to the low frequency side of the attenuation band. However, the insertion loss in the pass band is smaller than the maximum insertion loss, as indicated by the solid line in the graph of the figure. Although there is another limitation at the end of the high frequency side of the hatched portion, the high frequency region of the pass band is not important here.
    The dielectric block has a positive dielectric constant-temperature coefficient. As a result, the passage characteristic of the dielectric filter at high temperature moves toward the direction of the low frequency band, as indicated by the dotted line in each graph of the figure. In addition, according to the conductivity-temperature coefficient of the electrode, Qo is deteriorated, whereby the insertion loss is increased. As a result, as the temperature rises, the entire waveform of the pass characteristic moves in an oblique direction to the lower left in each graph of the figure. As shown in Fig. 3A, the shoulder portion of the waveform showing the passage characteristic even at high temperatures does not exceed the threshold.
    In the case of forming a dielectric filter using a dielectric material having a dielectric constant-temperature coefficient of approximately zero, the pass characteristic moves downward as shown in the graph of FIG. 3B, so that the shoulder portion indicated by the symbol B at a constant temperature has a threshold point. Beyond
    4 shows the temperature characteristics of two dielectric materials. With respect to the resonant frequency of the dielectric resonator using the dielectric material exhibiting the characteristics shown by the solid line, when the temperature is 25 ° C as the reference temperature, as the temperature is higher than 25 ° C, the resonance frequency is lowered, and at a temperature of + 85 ° C. The resonance frequency changes to -5ppm. Even when the temperature is lower than 25 ° C, the resonance frequency is lowered, and at a temperature of -35 ° C, the resonance frequency changes to -5 ppm. In addition, with respect to the resonant frequency of the dielectric resonator using the dielectric material exhibiting the characteristic shown by the dotted line in the graph of the drawing, when the temperature is 25 ° C as the reference temperature, the resonant frequency increases as the temperature becomes higher than 25 ° C. The resonance frequency changes to + 5ppm at + 85 ℃. Even when the temperature is lower than 25 ° C., the resonance frequency increases, and at a temperature of −35 ° C., the resonance frequency changes to +5 ppm. In addition, when a dielectric resonator is formed using a dielectric material exhibiting characteristics shown by dashed lines in the graph of the drawing, the resonant frequency of the resonator hardly changes over a range of -35 ° C to + 85 ° C.
    In FIG. 4, as the dielectric material exhibiting the characteristic of the upwardly protruding shape,
    BaO-PbO-Nd 2 O 3 -TiO 2 can be used.
    Dielectric material exhibiting downwardly protruding characteristics,
    BaO-Bi 2 O 3 -Nd 2 O 3 -Sm 2 O 3 -TiO 2 can be used.
    A dielectric material exhibiting flat properties.
    BaO-PbO-Bi 2 O 3 -Nd 2 O 3 -TiO 2 can be used. In addition, the dielectric constant-temperature coefficient (frequency-temperature coefficient in the case of a dielectric filter) can be arbitrarily determined by changing the composition ratio of these materials. This resonant frequency / temperature change is determined by the dielectric constant-temperature coefficient of the dielectric block. However, in general, since the temperature characteristic of the dielectric material is obtained by measuring the resonance frequency obtained when the dielectric resonator is constructed, the temperature characteristic of the dielectric material is represented by frequency / temperature coefficient (hereinafter referred to as TC).
    In the dielectric filter having the characteristics shown in Fig. 3A, as indicated by the symbol A shown in Fig. 4, the frequency decreases as the temperature rises to 25 ° C or more. In other words, a dielectric material of TC &lt; 0 is used.
    Next, the configuration of the dielectric filter according to the second embodiment will be described with reference to FIGS. 5A to 7.
    5A-5D are projection views of the dielectric filter. FIG. 5A shows a plan view, FIG. 5B shows a front view, FIG. 5C shows a bottom view, and FIG. 5D shows a right side. When the dielectric filter is mounted as a component on a printed circuit board, the front surface shown in FIG. 5B becomes a mounting surface with respect to the printed circuit board.
    The dielectric filter is constructed by forming various holes and electrodes for the rectangular parallelepiped dielectric block 1. Unlike the configuration shown in Fig. 1, in this embodiment, the resonance line hole 2d is further formed in the dielectric block 1, and the resonance line hole 12d is formed in the inner surface of the resonance line hole 2d. The dielectric block has a material of TC = 0 in the resonant line hole 2d direction with the center of the input / output coupling line hole 3b as a boundary position, and the dielectric block has a material of TC <0 in the other region. The other components are the same as those shown in FIG. When the dielectric block is formed, the dielectric material of TC &lt; 0 and the dielectric material of TC = 0 are integrally molded and integrally fired. In this case, since the base composition molds and fires the same dielectric material, its performance is substantially equivalent. As a result, molding and firing can be carried out simultaneously.
    The operation of the dielectric filter shown in Figs. 5A to 5D will be described as follows. First, the resonant lines 12a, 12b, and 12c formed in the resonant line holes 2a, 2b, and 2c each have capacitive coupling. As in the case of the first embodiment, the resonant lines 12a, 12b, and 12c are combinations of the combination of the comb-shaped lines (inductive coupling) formed by the stray capacitance Cs of the electrode non-forming part g and the capacitive coupling formed by the step hole. Combined. In this case, since the relationship of inductive coupling &lt; capacitive coupling is provided, the resonant lines 12a, 12b and 12c are capacitively coupled as a whole. An interdigital coupling is formed between the resonant line 12a and the input / output coupling line 13a and between the resonant line 12c and the input / output coupling line 13b, respectively. With this configuration, the component between the input and output terminals 7, 8 acts as a band pass filter. The resonant line 12d is interdigitally coupled with the input / output coupling line 13b to act as a trap resonator.
    6 is an equivalent circuit diagram of the dielectric filter. In Fig. 6, the symbol Zd represents the impedance generated by the resonance line 12d, and the symbol Zdo represents the impedance generated by the mutual capacitance generated between the impedance Zo generated by the input / output coupling line 13b and the resonance line 12d. The other parts are the same as those in the equivalent circuit shown in FIG.
    7 is a graph showing the passage characteristics of the dielectric filter. In this embodiment, the attenuation pole is generated by the resonant line 12d serving as a trap resonator. With such a configuration, rapid attenuation characteristics are exhibited in the region from the pass band to the attenuation band on the low frequency side. As shown in Fig. 7, the hatched portion in the pass band represents the maximum insertion loss and its frequency range, and the hatched portion in the attenuation band represents the minimum amount of attenuation and its frequency range. At normal temperatures, even when the shoulder portion approaches the threshold in the region from the pass band of the waveform showing the pass characteristic to the attenuation band on its low frequency side, the insertion loss in the pass band is the maximum insertion, as indicated by the solid line in the figure. Smaller than loss As shown in Fig. 5, the dielectric material of the bandpass filter portion is TC &lt; 0, so that the waveform showing the passage characteristic of the dielectric filter at a high temperature moves in an oblique direction to the lower left as a whole, as indicated by the dotted line in the figure. In this configuration, the shoulder portion of the waveform representing the pass characteristic does not exceed the threshold. In addition, since the dielectric material of the resonance line hole 2d is TC = 0, the frequency of the attenuation pole is constant regardless of the temperature change. With such a configuration, it is possible to constantly provide the amount of attenuation in the attenuation band, thereby constantly providing a predetermined minimum amount of attenuation in the attenuation band.
    Next, the configuration of the dielectric filter according to the third embodiment will be described with reference to FIGS. 8 and 9.
    In the above embodiments, a dielectric filter having passband characteristics is used, but similarly a band-proof dielectric filter is also applicable. 8 shows an equivalent circuit of the band-proof dielectric filter. In Fig. 8, the symbols Zb, Zd and Zf represent the impedances of the respective resonant lines, and the symbols Zbd and Zdf represent the respective impedances generated by the mutual capacitance obtained when interdigitally combining these lines. In addition, the symbols Za, Zc and Ze denote respective impedances of the resonant line as trap resonators; The symbol Zab represents the impedance generated by the mutual capacitance between the resonator Za and the resonator Zb, and acts as a phase circuit of π / 2, so that (Za, Zab) acts as a trap resonator. Similarly, the symbol Zcd represents the impedance generated by the mutual capacitance between the resonator Zc and the resonator Zd, and (Zc, Zcd) acts as a trap resonator; The symbol Zef represents the impedance generated by the mutual capacitance between the resonator Zf and the resonator Ze, and (Zf, Zef) acts as a trap resonator. Thus, a structure combining three trap resonators is obtained.
    9 is a graph showing the passage characteristics of the dielectric filter. In Fig. 9, the shoulder portion of the pass characteristic is near the threshold in the region from the pass band to the attenuation band. The dielectric material of the dielectric block is TC &gt; 0. As a result, the waveform of the passage characteristic at high temperature moves in an oblique direction to the lower right as indicated by the dotted line. With this configuration, even at high temperatures, the shoulder portion of the waveform does not exceed the maximum value of the pass loss.
    Next, the configuration of the dielectric duplexer according to the fourth embodiment of the present invention will be described with reference to FIGS. 10A to 12.
    10A-10D are projection views of the dielectric filter. FIG. 10A shows a plan view, FIG. 10B shows a front view, FIG. 10C shows a bottom view, and FIG. 10D shows a right side. When the dielectric duplexer is mounted as a component on a printed circuit board, the front surface shown in FIG. 10B becomes a mounting surface with respect to the printed circuit board.
    The dielectric duplexer is configured by forming various holes and electrodes for the rectangular parallelepiped dielectric block 1. More specifically, reference numerals 2a, 2b, and 2c denote resonant line holes, and resonant line 12a, 12b, and 12c are formed on the inner surface thereof. Similarly, reference numerals 5a, 5b, and 5c denote resonant line holes, and resonant line 15a, 15b, and 15c are formed on the inner surface thereof. In addition, reference numerals 3a, 3b, and 3c denote input / output coupling line holes, and input / output coupling lines 13a, 13b, and 13c are formed on the inner surface thereof. These holes are step holes in which the inner diameter of the holes changes at a constant rate. On the outer surface of the dielectric block 1, continuous input / output terminals 7, 8, and 9 are formed from input / output coupling lines 13a, 13b, and 13c, respectively, and a ground electrode 10 is formed on approximately the front face (side 6) except these input / output terminals. Further, electrode non-forming portions (conductor non-forming portions) indicated by the symbol "g" are formed in the vicinity of the end portion of the large side of the inner diameter of the step hole having the resonant lines 12a, 12b, 12c, 15a, 15b, and 15c, respectively. In each part, the floating capacity Cs is generated.
    The dielectric block 1 described above has regions of four dielectric materials, TC = 0, TC> 0, TC <0, and TC = 0, as shown in FIG. 10B.
    Next, the operation of the dielectric duplexer will be described as follows. First, the resonant lines 12a, 12b, and 12c formed in the resonant line holes 2a, 2b, and 2c each have capacitive coupling. The resonant lines 12a, 12b, and 12c are combined by a combination of a comb-shaped line (inductive coupling) formed by the stray capacitance Cs of the electrode non-forming portion g and a capacitive coupling formed by a step hole. However, in this case, since the relationship of inductive coupling &gt; capacitive coupling is provided, the resonant lines 12a, 12b and 12c make capacitive coupling as a whole. An interdigital coupling is formed between the resonant line 12a and the input / output coupling line 13a and between the resonant line 12c and the input / output coupling line 13b, respectively. In addition, an interdigital coupling is formed between the resonance line 12d and the input / output coupling line 13b.
    On the other hand, the resonant lines 15a, 15b, and 15c each have capacitive coupling. The resonant lines 15a, 15b, and 15c are combined by a combination of a comb-like line formed by the stray capacitance Cs of the electrode non-forming portion g (inductive coupling) and a capacitive coupling formed by a step hole. In this case, since the relationship of inductive coupling <capacitive coupling is provided, the resonant lines 15a, 15b, and 15c are capacitively coupled as a whole. An interdigital coupling is formed between the resonant line 15a and the input / output coupling line 13c, and between the resonant line 15c and the input / output coupling line 13a, respectively, and an interdigital coupling is also formed between the resonant line 15d and the input / output coupling line 13c.
    11 is an equivalent circuit diagram of the dielectric filter described above. The symbols Z1a, Z1b and Z1c represent respective impedances generated by the resonant lines 15a, 15b and 15c shown in FIG. 10; Symbol Z1d represents the impedance generated by the resonance line 15d; The symbol Z2d represents the impedance generated by the resonance line 12d. The symbols Z2a, Z2b and Z2c represent respective impedances generated by the resonant lines 12a, 12b and 12c shown in FIG. 10; Symbols Z1i, Zio, and Z2o represent the impedances generated by the input / output coupling lines 13c, 13a, and 13b shown in FIG. Symbol Z1id represents an impedance generated by mutual capacitance generated between the resonance line 15d and the input / output coupling line 13c; The symbol Z2od represents the impedance generated by the mutual capacitance generated between the resonance line 12d and the input / output coupling line 13b. Symbol Z1ab represents an impedance generated by mutual capacitance generated between the resonance line 15a and the resonance line 15b; Symbol Z1bc represents an impedance generated by mutual capacitance occurring between the resonance line 15b and the resonance line 15c; Symbol Z2ab represents the impedance generated by the mutual capacitance generated between the resonance line 12a and the resonance line 12b; The symbol Z2bc represents the impedance generated by the mutual capacitance generated between the resonance line 12b and the resonance line 12c. Symbol Z1co represents an impedance generated by mutual capacitance generated between the resonance line 15c and the input / output coupling line 13a; The symbol Z2ai represents the impedance generated by the mutual capacitance generated between the resonance line 12a and the input / output coupling line 13a.
    With this configuration, each of the transmission filter and the reception filter is formed of three stage resonators and one stage resonator.
    12A and 12B are graphs showing passage characteristics of the dielectric duplexer. In this example, the transmission filter makes it possible to penetrate the signal in the transmission band and attenuate the signal in the reception band on the high frequency side. The reception filter makes it possible to penetrate the signal in the reception band and attenuate the signal in the transmission band on the low frequency side. In the transmission filter, an attenuation band formed by the trap resonator described above is formed on the high frequency side of the pass band, and in the reception filter, an attenuation band formed by the trap resonator described above is formed on the low frequency side of the pass band.
    The hatched portions in each graph of the figure represent the maximum insertion loss and the minimum amount of attenuation and their frequency ranges. At normal temperatures, the shoulder portion is near the threshold in the region from the pass band to the attenuation band of the waveform exhibiting pass characteristics. However, the insertion loss in the pass band is smaller than the maximum insertion loss, as indicated by the solid line in the figure.
    Since TC &gt; 0 in the dielectric material of the resonator portion that generates the bandpass characteristics of the transmission filter, the waveform showing the transmission characteristics of the transmission filter at a high temperature moves in an oblique direction to the lower right, as indicated by the dotted line. As a result, as shown in Fig. 12A, the shoulder portion of the waveform in which the transmission filter exhibits passage characteristics even at high temperatures does not exceed the threshold. In addition, since TC <0 in the dielectric material of the resonator portion that generates the band pass characteristics of the receive filter, the waveform representing the pass characteristic of the receive filter at a high temperature moves in an oblique direction to the lower left. As a result, as shown in FIG. 12A, the shoulder portion of the waveform showing the passage characteristic even at high temperatures does not exceed the threshold. In addition, since TC = 0 in the dielectric material of the resonator portion which generates band pass characteristics of each of the transmission filter and the reception filter, it is necessary to constantly provide the amount of attenuation in the reception band of the transmission filter and the transmission band of the reception filter even at a high temperature. It is possible.
    4 is used as the dielectric material of the resonator portion that generates the bandpass characteristics of the transmission filter, and a symbol A of FIG. 4 is used as the dielectric material of the resonator portion that generates the bandpass characteristics of the reception filter. Use the indicated material. As a result, at a temperature lower than 25 ° C., as shown in FIG. 12B, the pass band characteristic of the transmission filter moves in an oblique direction to the upper right in the drawing, and the pass band characteristic of the receiving filter is oblique to the upper left in the drawing. Go to. Therefore, insertion loss of the transmission filter and the reception filter becomes better at low temperatures.
    Fig. 13 is a block diagram showing the construction of a communication device according to the fifth embodiment. In Fig. 13, the symbol ANT represents a transmit / receive antenna; Represents a symbol DPX duplexer; The symbols BPFa, BPFb and BPFc each refer to a band pass filter; The symbols AMPa and AMPb each represent an amplifying circuit; The symbols MIXa and MIXb each represent a mixer; The symbol OSC stands for oscillator; The symbol DIV represents a frequency divider or synthesizer. MIXa modulates the frequency signal output from the DIV into a modulated signal, and BPFa penetrates only signals in the transmission frequency band, and AMPa power-amplifies this signal and transmits it from the ANT via DPX. The BPFb penetrates only the reception frequency band signal of the signal output from the DPX, and the AMPb amplifies this penetrating signal. The MIXb mixes the frequency signal outputted from the BPFc and the received signal and outputs the intermediate frequency signal IF.
    As the duplexer DPX shown in Fig. 13, it is possible to use a dielectric duplexer having the structure shown in Figs. 10A to 10D. In addition, it is possible to use a dielectric filter having the structure shown in Figs. 5A to 5D as the band pass filters BPFa, BPFb and BPFc. With this configuration, a compact communication device is manufactured as a whole.
    As described above, according to the present invention, even if the pass characteristic of the filter changes according to the temperature rise and the temperature decrease, the shoulder portion is moved to avoid the threshold in the region from the pass band to the attenuation band, so that the specific characteristic can be maintained. have.
    Further, according to the present invention, the attenuation characteristic near the attenuation pole is constant irrespective of temperature change, so that a specific attenuation characteristic can be maintained.
    Further, according to the present invention, in the case of constructing the dielectric filter by discontinuously combining the dielectric resonators, structural misconception can be solved by the present invention.
    In addition, according to the present invention, the insertion loss of the pass band is further reduced, and the insertion loss in the shoulder portion of the pass band adjacent to the attenuation band can be kept at a low level over a wide temperature range.
    In addition, according to the present invention, a large amount of attenuation can be obtained in the attenuation band, and at the same time, the insertion loss can be kept at a low level over a wide temperature range in the shoulder portion of the pass band adjacent to the attenuation band.
    Furthermore, according to the present invention, in both the transmission filter and the reception filter, the shoulder portion of the pass characteristic in the region from the pass band to the attenuation band does not exceed the maximum insertion loss over a wide temperature range, thereby maintaining the function of the duplexer. have.
    In addition, according to the present invention, in the case of forming a dielectric duplexer by integrally molding or integrally firing two dielectric filters with a single dielectric block, no structural misunderstanding occurs.
    In addition, according to the present invention, a communication apparatus capable of maintaining a specific signal processing function of a high frequency circuit portion over a wide temperature change is obtained.
    Although the present invention has been specifically illustrated and described with reference to preferred embodiments of the invention, it is apparent to those skilled in the art that modifications and variations other than those described herein may be made without departing from the scope of the invention. It will be understood that it is possible.
    权利要求:
    Claims (8)
    [1" claim-type="Currently amended] Has an attenuation band close to the pass band;
    A threshold frequency position of a defined maximum insertion loss is placed in close proximity to a shoulder portion of a waveform which exhibits a pass characteristic in which insertion loss is increased in the region from the pass band to the attenuation band;
    And the temperature characteristic of the dielectric material is determined such that the shoulder portion moves in the direction of the attenuation zone as the temperature rises and decreases.
    [2" claim-type="Currently amended] 2. The dielectric filter of claim 1, wherein the dielectric filter comprises a plurality of dielectric resonators; At least one of the dielectric resonators is a trap resonator forming an attenuation pole in the region from the shoulder portion to the attenuation band; And determine a temperature characteristic of the dielectric material such that a change in resonant frequency with respect to a temperature change in the trap resonator is less than a change in resonant frequency with a temperature change in another dielectric resonator.
    [3" claim-type="Currently amended] The dielectric filter according to claim 2, wherein the plurality of dielectric resonators are integrally molded or integrally fired as a single dielectric block.
    [4" claim-type="Currently amended] 2. The dielectric filter according to claim 1, wherein the dielectric filter is a band pass filter including a plurality of dielectric resonators using the pass band as a range of resonant frequencies.
    [5" claim-type="Currently amended] 2. The dielectric filter of claim 1, wherein the dielectric filter is a bandpass filter including a plurality of dielectric resonators using the attenuation band as a range of resonance frequencies.
    [6" claim-type="Currently amended] A dielectric duplexer comprising two dielectric filters according to any one of claims 1, 2, 4 and 5.
    One of the two filters is a dielectric filter in which the low frequency band of the filter is an attenuation band and the high frequency band of the filter is a pass band;
    The other filter is a dielectric duplexer, wherein the low frequency band of the filter is a pass band and the high frequency band of the filter is a dielectric filter.
    [7" claim-type="Currently amended] 7. The dielectric duplexer according to claim 6, wherein the two dielectric filters are integrally molded or integrally fired as a single dielectric block.
    [8" claim-type="Currently amended] A communication apparatus comprising one of the dielectric filter according to any one of claims 1 to 5 and the dielectric duplexer according to any one of claims 6 and 7.
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    同族专利:
    公开号 | 公开日
    DE60037770D1|2008-03-06|
    CN1264186A|2000-08-23|
    EP1024547B1|2008-01-16|
    JP2000223908A|2000-08-11|
    DE60037770T2|2009-01-15|
    JP3468143B2|2003-11-17|
    CN1187864C|2005-02-02|
    EP1024547A2|2000-08-02|
    EP1024547A3|2002-03-27|
    US6411177B1|2002-06-25|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    1999-01-28|Priority to JP01976799A
    1999-01-28|Priority to JP11-19767
    2000-01-24|Application filed by 무라타 야스타카, 가부시키가이샤 무라타 세이사쿠쇼
    2000-09-25|Publication of KR20000057794A
    2002-01-09|Application granted
    2002-01-09|Publication of KR100319812B1
    优先权:
    申请号 | 申请日 | 专利标题
    JP01976799A|JP3468143B2|1999-01-28|1999-01-28|Dielectric filter, dielectric diplexer and communication device|
    JP11-19767|1999-01-28|
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