1291848 九、發明說明： •【發明所屬之技術領域】 .本發明係關於一種高頻信號印刷電路板之改良結構，尤指一 種能提咼印刷電路板上信號傳輸線阻抗大小之印刷電路板改良 結構。 【先前技術】 IEEE 1394(以下簡稱1394)是一種信號傳輸之技術規範，符合 這種規範之高速串列匯流排之傳輸速率可以達到4〇〇Mbps，利用 1394技術可以將電腦和攝影機、高速硬碟、音響等多媒體設備連 _ 接。1394b是1394之升級版本，採用這種信號傳輸線可提供更高 之傳輸性能，傳輸速率可高達3200 Mbps、傳輸距離可長達1〇〇 米以及實現和各種有線媒體如塑膠光纖、玻璃纖維、遮罩雙绞線、 非遮罩雙絞線等連接。 ' ' 一般來說，印刷電路板厚度越薄，其信號傳輸性能越好，例 如使用固壓片型號爲2116之印刷電路板在匯流排高速運轉時噪 音較大，延遲時間及上升時間較長，信號傳輸效果不理想，但若 使用1080型號之固壓片便會使上述問題得到改善。因爲1〇8〇型 號固壓片厚度小於2116型號固壓片厚度，故減少了整個印刷電路 鲁 板厚度，印刷電路板厚度之減小可有效減少高速運轉匯流排時産 生之串擾噪音’知:南#號傳輸性能。惟，使用1080型號固壓片後， 印刷電路板之信號傳輸線阻抗值減小，達不到信號傳輸線 所要求之阻抗值。 U ~ 請參閱第一圖，其爲一種高頻信號印刷電路板結構示意圖。 一印刷電路板10上設有複數信號傳輸線11、一第一接地層13、 一第二接地層14以及複數介質層15 ,其中該等信號傳輸線n分 別包括一對差分彳§號線110、112。W表示每一差分信號線之寬 度’ H1表示该荨信號傳輸線11與第一接地層η之距離，$表示 每對差分信號線110、112間之距離。該等信號傳輸線u之阻抗 Z主要和信號傳輸線11與第一接地層13之距離H1、差分信號線 5 1291848 之寬度w、每對差分信號線lio、112間之距離s有關，可簡單 表示為：Z-= H1 · S/W，即阻抗z與HI、S成正比，與W成反 比。因此當使用1080型號固壓片之後，由於該印刷電路板1〇之 厚度減小，該等信號傳輸線11與第一接地層13之距離HI隨之 滅小，在不改變差分信號線之線寬W和每對差分信號線11〇、112 間之距離S之情況下，該等信號傳輸線11之阻抗減小，達不到 l394b信號傳輸線所要求之阻抗大小。 【發明内容】 鑒於以上内谷，有必要提供一種能提高印刷電路板上信號傳 輸線阻抗大小之印刷電路板改良結構。1291848 IX. Description of the invention: • Technical field to which the invention pertains. The present invention relates to an improved structure of a high-frequency signal printed circuit board, and more particularly to an improved printed circuit board structure capable of improving the impedance of a signal transmission line on a printed circuit board. . [Prior Art] IEEE 1394 (hereinafter referred to as 1394) is a technical specification for signal transmission. The transmission rate of high-speed serial buss conforming to this specification can reach 4 Mbps, and 1394 technology can be used to computer and camera, high-speed hard. Multimedia devices such as dishes and stereos are connected. 1394b is an upgraded version of 1394. This signal transmission line can provide higher transmission performance, transmission rate up to 3200 Mbps, transmission distance up to 1 〇〇m, and realization of various wired media such as plastic optical fiber, fiberglass, and cover. Wiring twisted pair, uncovered twisted pair, etc. ' ' Generally speaking, the thinner the thickness of the printed circuit board, the better the signal transmission performance. For example, the printed circuit board with the solid-pressed chip type 2116 has higher noise during the high-speed operation of the bus bar, and the delay time and rise time are longer. The signal transmission effect is not satisfactory, but the use of the 1080 model of the solid pressure sheet will improve the above problems. Because the thickness of the 1〇8〇 type solidified sheet is less than the thickness of the 2116 model, the thickness of the printed circuit board is reduced. The reduction of the thickness of the printed circuit board can effectively reduce the crosstalk noise generated when the bus is operated at high speed. South # number transmission performance. However, after using the 1080 type solid-state film, the signal transmission line impedance of the printed circuit board is reduced, and the impedance value required for the signal transmission line is not achieved. U ~ Please refer to the first figure, which is a schematic diagram of a high-frequency signal printed circuit board structure. A printed circuit board 10 is provided with a plurality of signal transmission lines 11, a first ground layer 13, a second ground layer 14, and a plurality of dielectric layers 15, wherein the signal transmission lines n respectively comprise a pair of differential lines 110, 112. . W indicates the width of each differential signal line 'H1' indicates the distance between the 荨 signal transmission line 11 and the first ground layer η, and $ indicates the distance between each pair of differential signal lines 110, 112. The impedance Z of the signal transmission lines u is mainly related to the distance H between the signal transmission line 11 and the first ground layer 13, the width w of the differential signal line 5 1291848, and the distance s between each pair of differential signal lines lio and 112, which can be simply expressed as :Z-= H1 · S/W, that is, the impedance z is proportional to HI and S, and inversely proportional to W. Therefore, after using the 1080 type solid pressing sheet, since the thickness of the printed circuit board 1 is reduced, the distance HI between the signal transmission lines 11 and the first ground layer 13 is reduced, and the line width of the differential signal line is not changed. In the case of W and the distance S between each pair of differential signal lines 11〇, 112, the impedance of the signal transmission lines 11 is reduced to the magnitude of the impedance required by the l394b signal transmission line. SUMMARY OF THE INVENTION In view of the above inner valleys, it is necessary to provide an improved printed circuit board structure capable of improving the impedance of a signal transmission line on a printed circuit board.
一種高頻信號印刷電路板改良結構，該印刷電路板上設有複 數信號傳輸線、一離該等信號傳輸線距離較近之第一接地層和二 離該等信號傳輸線距離較遠之第二接地層，該等信號傳輸線以該 第二接地層作為參考地面層，從而提高信號傳輸線阻抗值大小。Λ 相較習知技術，該高頻信號印刷電路版之改良結構即能提高 信號傳輸線之傳輸性能又能提高信號傳輸線之阻抗值以符合高 頻信號傳輸中之阻抗要求。 ° ^ 【實施方式】 請芩閱第二圖’本發明較佳實施方式包括一印刷電路板2〇。 該印刷電路板20上設有複數信號傳輸線21、一第一接地層23、 一第二接地層24及複數介質層25，其_該第一接地層23上對應 該等信號傳輸線21具有衩數鏤空部230。每-信號傳輸線21係 由一對差分信號線210、212所組成。 每一差分信號線之寬度爲w，每對差分信號線21〇、212間之 距離爲S，該等信號傳輸線21離第一接地層23之距離爲H1， 該第一接地層24之距雄爲H2，該第一接地層23之每一鏤空部 230之寬度爲B。由於每一信號傳輸線21位於該第一接地^3 之對應鏤空部230之上方，因此該等信號傳輪線21繞過較近之 第一接地層23而以較遠之第二接地層24作爲參考地面層。 1291848 6亥專信號傳輸線21之阻抗Z和信號傳輸線21與第一接地層 23間之距離H1、每對差分信號線210、212間之距離S成正比， - 和差分信號線之寬度W成反比，即Z<- H1 · S/W。相較習知技 術，差分信號線之寬度W和每對差分信號線210、212間之距離 S保持不變以保持信號傳輸線21的傳輸特性。然使用1〇8〇型號 ·· 固壓片代替2116型號固壓片，該印刷電路板20之厚度減小會導 致該等信號傳輸線21與第一接地層23間之距離111減小，；^而 使該等信號傳輸線21之阻抗z減小，由於該等信號傳輸線21之 參考地面層由較近之第一接地層23轉換爲較遠之第二接地層 φ 24，該等信號傳輸線21與參考地面層間之距離爲H2，使該等^ 號傳輪線21之阻抗Z增大，符合高頻信號傳輸中之阻抗要求。° 該第一接地層23之每一鏤空部230之寬度B略大於該等信號 傳輸線21與該第二接地層24之間之距離H2,以避免産生雜訊^ 擾。 、 請參閱第三圖，爲本發明之另一較佳實施方式，與上述實施 方式不同之處係對應於該等信號傳輸線21下方之該第一接地層 23完全鏤空，使該等信號傳輸線21以較遠之第二接地層24爲^ 考地面層，以達到提高該等信號傳輸線21阻抗值之目的。 綜上所述’本發明確已符合發明專利之要件，爰依法提出專 _ 利申請。惟，以上僅為本發明之較佳實施例，舉凡熟習本發明技An improved structure of a high-frequency signal printed circuit board, wherein the printed circuit board is provided with a plurality of signal transmission lines, a first ground layer that is relatively close to the signal transmission lines, and a second ground layer that is far away from the signal transmission lines The signal transmission lines use the second ground layer as a reference ground layer, thereby increasing the impedance value of the signal transmission line.改良 Compared with the prior art, the improved structure of the high-frequency signal printed circuit board can improve the transmission performance of the signal transmission line and increase the impedance value of the signal transmission line to meet the impedance requirement in high-frequency signal transmission. [Embodiment] Please refer to the second drawing. A preferred embodiment of the present invention includes a printed circuit board 2A. The printed circuit board 20 is provided with a plurality of signal transmission lines 21, a first ground layer 23, a second ground layer 24, and a plurality of dielectric layers 25, and the first ground layer 23 has corresponding number of signal transmission lines 21 Hollow section 230. Each of the signal transmission lines 21 is composed of a pair of differential signal lines 210, 212. The width of each differential signal line is w, the distance between each pair of differential signal lines 21〇, 212 is S, the distance between the signal transmission lines 21 from the first ground layer 23 is H1, and the distance between the first ground layer 24 is For H2, each hollow portion 230 of the first ground layer 23 has a width B. Since each signal transmission line 21 is located above the corresponding hollow portion 230 of the first ground, the signal transmission lines 21 bypass the first ground layer 23 and the second ground layer 24 is used. Refer to the ground floor. 1291848 The impedance Z of the signal transmission line 21 and the distance H1 between the signal transmission line 21 and the first ground layer 23 are proportional to the distance S between each pair of differential signal lines 210 and 212, and are inversely proportional to the width W of the differential signal line. , that is, Z<- H1 · S/W. The width W of the differential signal line and the distance S between each pair of differential signal lines 210, 212 remain unchanged to maintain the transmission characteristics of the signal transmission line 21 as compared with the prior art. However, instead of the 2116 type solid-pressing sheet, the thickness of the printed circuit board 20 is reduced by the thickness of the printed circuit board 20, and the distance 111 between the signal transmission lines 21 and the first ground layer 23 is reduced. The impedance z of the signal transmission lines 21 is reduced, since the reference ground layer of the signal transmission lines 21 is converted from the closer first ground layer 23 to the farther second ground layer φ 24, the signal transmission lines 21 and The distance between the reference ground layers is H2, so that the impedance Z of the pass wires 21 is increased, which is in accordance with the impedance requirement in high-frequency signal transmission. The width B of each of the hollow portions 230 of the first ground layer 23 is slightly larger than the distance H2 between the signal transmission lines 21 and the second ground layer 24 to avoid noise. Referring to the third embodiment, another preferred embodiment of the present invention, which is different from the above embodiment, is that the first ground layer 23 corresponding to the signal transmission line 21 is completely hollowed out, so that the signal transmission lines 21 are made. Taking the second ground layer 24 farther away is the ground layer to achieve the purpose of increasing the impedance value of the signal transmission lines 21. In summary, the present invention has indeed met the requirements of the invention patent, and has filed a special patent application in accordance with the law. However, the above is only a preferred embodiment of the present invention, and it is familiar with the present invention.
藝之人士爰依本發明之精神所作之等效修飾或變化，皆應涵蓋在 以下申請專利範圍内。I J291848 【圖式簡單說明】 ，一圖係習知技術之高頻信號印刷電路板結構示意圖。 第二圖係本發明之一較佳實施方式之高頻信號印刷電路板改 良結構示意圖。 第三圖係本發明之另一較佳實施方式之高頻信號印刷電路板 改良結構示意圖。 【主要元件符號說明】 印刷電路板 20 介質層 25 第一接地層 23 第二f妾地層 24 鏤空部 230 信號傳輸線 21 差分信號線 210、 212Equivalent modifications or variations of the skilled person in accordance with the spirit of the invention are intended to be included within the scope of the following claims. I J291848 [Simple description of the diagram], a diagram is a schematic diagram of the structure of a high-frequency signal printed circuit board of the prior art. The second drawing is a schematic view showing a modified structure of a high frequency signal printed circuit board according to a preferred embodiment of the present invention. The third drawing is a schematic view of an improved structure of a high frequency signal printed circuit board according to another preferred embodiment of the present invention. [Description of main component symbols] Printed circuit board 20 Dielectric layer 25 First ground plane 23 Second f妾 formation 24 Hollow section 230 Signal transmission line 21 Differential signal line 210, 212