Patent Publication Number: US-2005134408-A1

Title: Circuit device and printed circuit board

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      This invention relates to a circuit device and a printed board. More particularly, the invention relates to a forming conductive pattern in inside layer in the dielectric substrate and earthed conductor in outside layer in the dielectric substrate. Moreover this invention enables the area of the earthed conductor and a position to change so that a frequency characteristic, which is set up by conductive pattern, may become desired characteristic.  
      2. Description of the Related Art  
      Recently, because of the development of the information and communication technology, mobile communication machines, ISDN and computer devices carry circuit blocks to transmit data at high speed by using the radio or some lines.  
      When such circuit blocks are carried on machines, not only high speed can transmit data but also it hopes for compositions in consideration of the noise. Furthermore, the miniaturization, complexation and multifunctionalizaton of parts are attempted when circuit blocks are carried on mobile devices. For example, it is unacceptable to realize low-pass filters, high-pass filters, band-pass filters and couplers with lumped parameter circuits using chip parts such as condensers and coils in high frequency applications which made a microwave band and millimeter wave band as a career like radio LAN (Local Area Network) and variety terminal of the communication devices. So low-pass filters, high -pass filters, band-pass filters and coupler using a distributed parameter circuit like a micro-strip line and strip line are used.  
      The coupler made to combine resonator conductive pattern of about λ/4 (λ:wave length) is being used as high-performance band-pass filters.  FIG. 1  shows a coupler that has resonator conductive patterns  202  arranged in cascade-shaped on the surface of dielectric substrate  200  to combine in the surface of pattern and adjacent resonator conductive patterns have the part of the pile of the length about λ/4. However it is difficult to minimize band-pass filters because resonator conductive patterns have such as the part of the pile of the length about λ/4. Therefore resonator conductive patterns are formed on not the surface layer of the substrate but the inside layer, in other words, miniaturization is realized by the tri-plate structure.  FIG. 2  shows the oblique figure of a known band-pass filter that has tri-plate structure. Earthed conductors  302  and  303  are formed on both sides of dielectric substrate (insulating substrate)  301  and resonator conductive patterns  304   a  and  304   b  are established as an annex between earthed conductor  302  and  303  to compose band-pass filters. These resonator conductive patterns  304   a ,  304   b  are established as an annex to have the pile of the length about λ/4 and one edge of pattern is short-circuited with earthed conductor  302 . Moreover contacting earthed conductor  302  and earthed conductor  303  shield resonator conductive patterns  304   a  and  304   b.    
      When band-pass filters are composed by using the distributed parameter circuit, shown in  FIG. 3A , the pass band and the shield characteristics depend on electromagnetic field between resonator conductive pattern  401   a  and  401   b  that are formed on the dielectric substrate  400 , and resonator conductive pattern  401   a ,  401   b  and earthed conductors  402  and  403 . Shown in  FIG. 3B , in odd exciting mode the electric field strength changes corresponding to the distance d of resonator between conductive patterns  401   a  and  401   b . Moreover, shown in  FIG. 3C , in even exciting mode the electric field strength changes corresponding to the distance of resonator conductive pattern  401   a ,  401   b  and earthed conductors  402  and  403 , in other words the thickness K of dielectric substrate. The electric field strength changes corresponding to the width of resonator conductive pattern, too. In odd exciting mode and even exciting mode when the strength of the electric field changes like this, a degree of combination of resonator conductive pattern changes, and passes band characteristics change, too. Therefore when band-pass filters are designed, the thickness of the resonator conductive pattern and dielectric substrate is decided to obtain desired characteristics.  
      However when the thickness of resonator conductive pattern and dielectric substrate is designed to obtain desired characteristics, sometimes we cannot obtain desired characteristics because of dispersions during the manufacture process. In such a case characteristics are prepared by conducting additional process of changing the position and area of resonator conductive pattern. In the band-pass filter having tri-plate structure, resonator conductive pattern arranged between earthed conductors so it is impossible to reprocess resonator conductive pattern. Therefore it requires controlling strictly the size of resonator conductive pattern, the thickness of dielectric substrate and dielectric constant so it causes the decline of yield and cost up.  
     SUMMARY OF THE INVENTION  
      This invention provides circuit devices and printed boards, which have desired frequency characteristics with miniaturization and thinning and without introducing cost-up.  
      This circuit device, having the conductive pattern which is formed in inside layer of dielectric substrate and the earthed conductor is formed in outside layer on said dielectric substrate, and the frequency characteristic is set up by said conductive pattern, provides desired frequency characteristic by changing the area and position of the earthed conductor.  
      The printed board has the conductor pattern that is formed in inside layer of first area in dielectric substrate and the earthed conductor which is formed in outside of first area in dielectric substrate. Moreover the frequency characteristic is set up by the conductive pattern. The printed board has circuit devices having the desired frequency characteristic by changing the area and position of the earthed conductor, and circuit mounting parts having a signal processing circuit for processing signals (desired frequency characteristic) in the area that is different from the first area of dielectric substrate.  
      In accordance with the present invention, the conductive pattern is formed in inside layer in dielectric substrate to control distributed parameter circuit devices and patterns having one or plural rectangle-shaped areas without the earthed conductor, or the lattice-shaped earthed conductor formed in one or plural sides of outside of the dielectric substrate to change easily the area and position of the earthed conductor. 
    
    
     BRIEF DESCRIPTIONS OF THE DRAWINGS  
       FIG. 1  shows a known band-pass filter;  
       FIG. 2  shows a known band-pass filter having tri-plate structure;  
       FIGS. 3A  to  3 C show the behavior of a known band-pass filter in odd exciting mode and even exciting mode;  
       FIG. 4  shows the distributed parameter circuit device;  
       FIGS. 5A and 5B  show the behavior in odd exciting mode and even exciting mode;  
       FIGS. 6A  to  6 C show the structure of the band-pass filter  20 ;  
       FIG. 7  shows the frequency characteristic of the band-pass filter  20 ;  
       FIGS. 8A  to  8 B show the band-pass filter  30 ;  
       FIG. 9  shows the frequency characteristic of the band-pass filter  30 ;  
       FIGS. 10A and 10B  show the band-pass filter  40 ;  
       FIG. 11  shows the frequency characteristic of the band-pass filter  40 ;  
       FIGS. 12A and 12B  show another structure of the band-pass filter  20 ;  
       FIGS. 13A  to  13 C show the band-pass filter having the multi-layered structure;  
       FIG. 14  shows the printed board;  
       FIG. 15  is the oblique figure of the low-pass filter;  
       FIG. 16  is the oblique figure of the high-pass filter;  
       FIG. 17  is the oblique figure of the coupler;  
       FIG. 18  is the oblique figure of the directional coupler;  
       FIG. 19  is the superficial antenna; and  
       FIG. 20  is the oblique figure of the lumped parameter circuit device. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
      The embodiment of the present invention will become better understood with reference to the following description and drawings. Conductive patterns are formed on the substrate to control circuit devices, moreover, shown in  FIG. 4  in the circuit device having earthed conductor which is formed on the dielectric substrate, e.g. the distributed parameter circuit device  10  having tri-plate structure, lattice-shaped earthed conductor  12  is formed on the dielectric substrate  11  to change the area and position of the earthed conductor. The earthed conductor  12  connects at layer via hole  13  with the earthed conductor (not illustrated) on the opposition side. Therefore, the conductive pattern, which control circuit device in the dielectric substrate, is shielded with earthed conductors and via hole.  
      When the pattern  12  which is formed the outside of the dielectric substrate forms the area  15  without the earthed conductor, shown in  FIG. 5A  in the odd exciting mode, shown in  FIG. 5B  in the even exciting mode, the frequency characteristic become be able to change because of changing the distribution of electromagnetic field between conductive patterns  17  and the earthed conductor that control actuation of circuit device. Therefore changing of the area and position of the earthed conductor can adjust the frequency characteristic of the distribution parameter circuit device having tri-plate structure to desired characteristic. For example, these measures are forming conductive parts on the area  15  without the earthed conductor, changing the position and amount of the conductive parts, and cutting earthed conductor between the areas without earthed conductor.  
       FIGS. 6A  to  6 C show the structure of the band-pass filter having tri-plate structure. This band-pass filter is impedance step type, that has the part of the pile of the adjacent resonator conductive pattern which has shorter length than λ/4.  
       FIG. 6A  is an oblique figure,  FIG. 6B  is a plan and  FIG. 6C  is a sectional view at line I-I′ in  FIG. 6B . Shown in  FIGS. 6A  to C, this band-pass filter has the earthed conductors  22   a  and  22   b  on both sides of the dielectric substrate (insulating substrate)  21 . Moreover the band-pass filter has two resonator conductive patterns  23   a  and  23   b  between earthed conductors  22   a  and  22   b  to compose the band-pass filter. One edge of the resonator conductive patterns  23   a  and  23   b  are shortened with earthed conductors  22   a  and  22   b  by layer via hole  24 . Expanding of the width of the pattern at the other edge (opening side) of the resonator conductive patterns  23   a  and  23   b  shortens the length of the pile of adjacent resonator conductive patterns by increasing the characteristic impedance at the short circuit side and decreasing the characteristic impedance at the opening side.  
      The earthed conductor  22   a  connects at said via hole  24  with  22   b , and resonator conductive patterns  23  and  23   b  are shielded with forming layer via hole  24  in the circumference them.  
      For example, the pattern having the conductive layer  26  which is formed at opposite side of the resonator conductive patterns  23   a  and  23   b , is formed on the earthed conductor  22   a , said conductive layer  26  has the area  25  without the earthed conductor which is formed in the surroundings of it.  
       FIG. 7  shows the frequency characteristic of the band-pass filter  20  and, in this figure, the frequency characteristic (illustrated by solid line in  FIG. 7 ) in the case of forming the conductive layer  26  having the area  25  without earthed conductor is enhanced in frequency band wider than that (illustrated by dotted line) in the case of deforming the area  25  without the earthed conductor.  
      Therefore designing resonator conductive pattern and dielectric substrate and forming the conductive layer  26  having the area  25  without the earthed conductor are provided desired frequency band having a desired frequency characteristic. When frequency characteristic is wider than desired frequency, you have only to form conductive parts e.g. copper foil, conductive paste and solder on the area  25  without earthed conductor so that frequency band will be narrow and you can obtain desired band-pass filter having a desired frequency characteristic. On the contrary, when the frequency characteristic is narrower than desired frequency band, you have only to cut the earthed conductor  2   a  and make the frequency band wide so that you can gain desired band-pass filter having a desired frequency characteristic.  
      How to make the band-pass filter  30  which formed a pattern on the earthed conductor  32 , said pattern is that rectangle-shaped non earthed conductive area  35  is formed on resonator conductive pattern or between resonator conductive patterns, as a method which made it change an area and a position of the earthed conductor is by forming the area without earthed conductor on the dielectric substrate, in shown  FIG. 8A . In the case the area and position of the earthed conductor can change by forming the conductive parts  38  on rectangle-shaped area  35  without earthed conductor, in shown  FIG. 8B .  
       FIG. 9  shows the frequency characteristic of the band-pass filter  30 , when the conductive parts  38  is formed on the rectangle-shaped area  35  without earthed conductor in the short circuit side, the frequency characteristic (solid line in  FIG. 9 ) is wider toward high band side than the frequency characteristic (dotted line in  FIG. 9 ) in the case of deforming conductive parts.  
      Therefore, forming the conductive parts  38  on the rectangle-shaped area  35  without earthed conductor, changing the position and amount of the conductive parts  38  or changing the area and position of earthed conductor by cutting earthed conductor, enable to obtain desired frequency characteristic. For example, when the frequency characteristic is narrower in high pass side than desired frequency band, you have only to form the conductive parts  38  on rectangle-shaped area  35  without earthed conductor and make the frequency band narrow in high pass side so that you can get the band-pass filter having desired frequency characteristic. On the contrary, when the frequency characteristic is wider in high pass side than desired frequency band, you have only to cut the earthed conductor  32  between rectangle-shaped areas  35  and make the frequency band wide in high pass side so that you can get the band-pass filter having desired frequency characteristic.  
      There is other method that the length in the signal input and output direction of the rectangle-shaped area  35  without earthed conductor, shown in  FIGS. 8A and 8B , is lengthened to provide the band-pass filter  40  by forming the rectangle-shaped area  45  without the earthed conductor, shown in  FIG. 10A . In the case, the frequency band (solid line in  FIG. 11 ) in forming the conductive parts  48  on center of each of the rectangle-shaped area  45  without earthed conductor is wider than the frequency characteristic (dotted line in  FIG. 11 ) in deforming the conductive parts  48 , shown in  FIG. 10B .  
      Therefore, forming the conductive parts  48  in the center of the rectangle-shaped area  45  without earthed conductor, changing the position of the conductive parts  48  or cutting the earthed conductor  42  to change the area and position of the earthed conductor, provide desired frequency characteristic. For example, when the frequency characteristic is narrower than desired, you have only to form the conductive parts  48  on rectangle-shaped area  45  without earthed conductor and make the frequency band wide so that you can get the band-pass filter having desired frequency characteristic. On the contrary, when the frequency characteristic is wider than desired frequency band, you have only to cut the earthed conductor  42  and make the frequency band narrow so that you can get the band-pass filter having desired frequency characteristic.  
      Moreover in the band-pass filter shown in  FIGS. 6A  to  6 C, the area  25  without the earthed conductor exchanges for the thin-filmed conductive layer  27  shown in  FIGS. 12A and 12B  so that the thin-filmed conductive layer is cut and processed easily, you can adjust the frequency characteristic easily by changing the area and position of the earthed conductor.  
      In accordance with said embodiment, the area without earthed conductor is formed on one side of earthed conductor, of course you can form the area without earthed conductor on another side of the earthed conductor as same. In the case, you may form same patterns on both sides and form different patterns.  
      You can adjust the frequency characteristic by using said method, when the band-pass filter has multi-layered structure, shown in  FIGS. 13A  to  13 C. Even if wiring pattern layer  53  is formed between resonator conductive pattern  51  and earthed conductor  52  as shown in  FIG. 13A , it is able to change the characteristic of the band-pass filter by forming the area  54  without earthed conductor. But, in this case because of forming the wiring pattern layer  53  between resonator conductive pattern  51  and the earthed conductor  52 , the amount of adjustment of the frequency characteristic is less than the amount of adjustment of the frequency in non multi-layered structure. When two band-pass filters  55   a  and  55   b  have laminated structure having unified earthed conductor  56 , you can adjust the frequency characteristic by forming the area  57  without the earthed conductor on outside layer which changes corresponding to the frequency characteristic of the band-pass filter and changing the area and position of the earthed conductor, shown in  FIG. 13B . Moreover, if the distance of the side of substrate having band-pass filter and resonator conductive pattern is short, forming the earthed conductor  58  on side surface and forming the area  59  without the earthed conductor on side surface of the substrate and changing the area and position of the earthed conductor is enable the frequency characteristic to change, shown in  FIG. 13C .  
      The above-mentioned description about said embodiment explains about the distributed parameter circuit device as the band-pass filter. When the printed board  60  which makes enable signal processing circuit  62 , e.g. MMIC, to mount on the substrate having the distributed parameter circuit device  61 , it is possible to change the area and position of the earthed conductor corresponding to the position of conductive pattern for setting up the distributed parameter circuit  61  device connecting at connecting via hole  63  with signal processing circuit by forming pattern on the earthed conductor  64 , shown in  FIG. 14 .  
      In accordance with said embodiment, forming the resonator pattern as the distributed parameter circuit device composes the band-pass filter, you can compose the low-pass filter and high-pass filter by changing the pattern.  
       FIG. 15  is the oblique figure of the low-pass filter  70 . The pattern  72   a  for the series inductance and the pattern  72   b  for the parallel capacity are formed in series and in turns on one side of the dielectric substrate  71 . Moreover, the earthed conductor  73  is formed on another side of the substrate. Plastering the dielectric substrate  71  formed the patterns  72   a  and  72   b  to the dielectric substrate  75  formed the earthed conductor  76  forms the band-pass filter  70  having the tri-plate structure. Changing the area and position of the earthed conductor by forming the area without the earthed conductor on side formed the earthed conductor provides desired frequency characteristic, as the band-pass filter.  
       FIG. 16  is the oblique figure of the high-pass filter. The patterns  82   a  and  82   b  for the parallel inductance are formed on one side of the dielectric substrate  81  and the earthed conductor  83  is formed on another side of the dielectric substrate  81 . The edges of the patterns  82   a  and  82   b  are shorted with the earthed conductor  83 . Producing the series capacity opposite to the patterns  82   a  and  82   b  and connecting the patterns with the earthed conductor form the patterns  86   a  and  86   b  and  86   c  for the parallel inductance on one side of the dielectric substrate  85 . The earthed conductor is formed on the side that is not signal input and output side. Moreover, the earthed conductor is formed on one side of the dielectric  89  substrate  88 .  
      The dielectric substrate  85  plasters to the patterns  82   a  and  82   b  on the dielectric substrate  81  and the dielectric substrates  88  plasters to the pattern  86  on the dielectric substrate  85 . When the dielectric substrate  81  plasters to the dielectric substrate  85 , the dielectric substrate  85  interpose between the patterns  82   a  and  82   b  and the patterns  86   a  and  86   b . When the dielectric substrate  85  plasters to the dielectric substrate  88 , the dielectric substrate  88  interpose between the pattern  86  and the earthed conductor  89 . In this case the dielectric substrate  81  plasters to the dielectric substrate  85 , and the dielectric substrate  85  plasters to the dielectric substrate  88 , at the same time, the earthed conductor  83  connect with earthed conductor  87  and the earthed conductor  87  connects with the earthed conductor  89  so that it forms the high-pass filter having tri-plate structure. In this case, changing the area and position of the earthed conductor by forming the area without the earthed conductor on side formed the earthed conductor  89  provides the desired frequency characteristic.  
      Moreover, the present circuit device is not limited to the distributed circuit device. In adjustment of characteristics of the coupler, antenna and the combination between layers of the distributed parameter device, changing the area and position of the earthed conductor provides the desired frequency characteristic.  FIG. 17  is the oblique figure of the coupler  90 , which cuts a direct correct portion. The coupler has the part of the pile of the length about ¼ λ of the conductive pattern  92   a  formed on the dielectric substrate  91  and the conductive pattern  92   b  formed on the substrate  91 . If the area and position of the earthed conductor  93  formed outside of conductive patterns  92   a  and  92   b  become to change easily, you can get the desired coupler.  FIG. 18  is the oblique figure of the directional coupler  95 , in same way, if the area and position of the earthed conductor  96  formed outside become to change easily, you can get the desired directional coupler.  FIG. 19  shows superficial antenna. The patch  101  for receiving and transmitting of the electric wave connects with the electric supply line  102 . When the protective layer  104  si formed on the side formed the patch  101  is formed, if the area and position of the earthed conductor  105  on backside becomes to change easily you can get the desired superficial antenna.  FIG. 20  is the oblique figure the lumped parameter circuit device having the condenser and coil formed by conductive pattern. For example, changing the area and position of the earthed conductor  112  which is formed opposite to the coil  110  to change the capacity of the coil  110  and the earthed conductor  112 , provides the desired characteristic.  
      Lattice-shaped earthed conductors are formed in  FIG. 14 ˜ FIG. 20 , of course, it is possible to form the earthed conductor as shown in  FIGS. 6A  to  6 C,  FIGS. 8A, 8B  and  FIGS. 10A, 10B . Moreover, if the pattern enables the area and position of the earthed conductor to change easily, it is not limited to said shape.  
      In accordance with the present invention, changing the area and position of the earthed conductor by forming conductive pattern in inside layer of the dielectric substrate and forming the earthed conductor in outside layer of the dielectric substrate, provides the desired frequency characteristic. Therefore, even if it is impossible to change the form of the conductive pattern of the inside layer because of laminated substructure, you can get the desired frequency characteristic. Moreover, even if the material accuracy and processing accuracy are not managed strictly, you have only to change the area and position of the earthed conductor, and you can adjust the frequency characteristic with precision.  
      In addition, because of forming the pattern, which can change the area and position on the earthed conductor, it is possible to get easily the desired frequency characteristic by using the pattern. In the case pattern is formed on one side or plural sides of the dielectric substrate, the adjustment range of the frequency characteristic can be expanded and the adjustment precision can be enhanced by forming same or difference pattern.  
      In the circuit device, having the conductive pattern which formed on inside layer of the first area of the dielectric substrate and the earthed conductor which formed on outsid are of the first area of the dielectric substrate, setting up the frequency characteristic using the conductive pattern and changing the area and position of the desired frequency characteristic of the earthed conductor provide the desired frequency characteristic. Moreover, it is possible to process the signal without noise or the influence of signal transmission lines by using the printed board having the circuit mounting part which has the signal processing circuit that is formed on the area which is different from the circuit device parts and the first area of the dielectric substrate, said the signal processing circuit processes the desired frequency characteristic signal.