200937734 九、發明說明： 【發明所屬之技術領域】 本發明係關於一種單極天線，特別是一種適用於行 通讯裝置之多頻草極天線。 【先前技術】 隨著無線通訊產業的蓬勃發展，現今幾乎已成為人手 ❹一機的普及情況，而行動電話的設計除了仍力求輕、薄、 短、小外，在通訊頻帶上的需求，已從原本的雙頻操作變 成多頻操作（四頻操作或五頻操作），使得行動電話所能 提供的無線通訊服務更多元化。而多頻天線的設計大致分 為多天線的設計及單一寬頻天線兩種，前者必然造成天線 擺放二間的規劃、尚天線製作成本以及電磁干擾等問題； 後者則是使得内部空間能得到有效的運用，成本也可以降 低、。因此設計具有多頻帶操作特性之單一天線為一較佳之 解决方案，不過，天線寬頻機制與技術之開發將會是另一 個挑戰，故天線設計需要尋求寬頻的解決方案來符合多頻 帶操作的需求。 二台灣專利公告號第541，759號“折疊式雙頻單極天線” 、台灣專利公告號第1221,042號“平面式多頻單極天線” 及口灣專利公告號第1234,9〇2號“三頻印刷式迂迴單極天 線”，皆是採用單饋入多支路單極天線的方式來達成多頻 5 200937734 操作，然而該幾項天線設計之多支路彼此的影響大，一方 面不但要考慮各支路末端彼此耦合的影響，尤其還要考慮 各支路頻率相近之共振模態彼此的影響，增加了設計的複 雜度。為了解決上述的問題，我們提出一種多頻單極天線 ，其所增加的支路與原有支路具有一特定間距，是採用電 磁耦合的方式來產生共振，因此增加的共振模態與原有頻 率相近的模態彼此之間的影響小’能在不需顧慮是否影響 原有模態之下，利用增加的共振模態結合原有模態來涵蓋 一較大的操作頻寬。換言之’其優點即是各支路具有獨立 操作的特性’能有效降低天線設計的複雜度以及設計所需 耗費的時間。更進一步，可加入適當的匹配電路來改善阻 抗匹配，並藉由並聯元件調整阻抗實部及阻抗虛部，及串 聯元件來調整阻抗虛部’以得到適當的阻抗實部搭配雙虛 部零點’將原本單一共振模態增為雙共振模態，進而達成 更寬頻操作。 【發明内容】 如上所述，本發明之目的在於提供一種適用於行動通 訊裝置之多頻單極天線設計’其可以涵蓋GSM850/900/1800 /1900/UMTS(824 - 894 MHz/890 - 960 MHz/1710 - 1880 MHz/1850 -1990 MHz/1920-2170 MHz)頻帶之操作。 本發明天線，包含：一介質基板、一接地面、一輻射 200937734 金屬部及一匹配電路。該接地面位於該介質基板上。該輻 射金屬部位於該介質基板上，與該接地面不互相重疊，該 轄射金屬部並包含：-第-金屬部’其一端為天線饋入點 ’該天線饋入點並大致位於該接地面之一邊緣處，其另一 端則為開路；一第二金屬部，其一端與該第一金屬部具有 一特定間距（小於3mm)，另一端為開路。該匹配電路位 於δ玄介質基板上’其一端連接至一信號源，另一端連接至 δ亥天線馈入點。s亥介質基板可以為一行動通訊裝置之系統 電路板，而該接地面可使用印刷或蝕刻技術形成於該介質 基板上。該輻射金屬部則可使用印刷或蝕刻技術形成於該 介質基板上，亦可使用一金屬片沖壓或切割製作而成。 在本項發明天線中，藉由第一金屬部共振出四分之一 波長模態（操作於約900 MHz)及倍頻模態（操作於約2200 MHz)’再加上第二金屬部，藉由該特定間距，由第一金 屬部電磁耦合共振出其四分之一波長模態（操作於約175〇 ® MHz ) ’進而涵蓋GSM900/1800/1900/UMTS操作。接下來增 加適當的匹配電路，在此採用高通形式之匹配電路，包含 至少一並聯電感及至少一串聯電容，其功用為降低對高頻 模態的影響’而能針對低頻的阻抗匹配做改善。選取適當 的元件值後，利用所得之適當的實部阻抗搭配雙虛部零點 ’將低頻由單一共振模態增為雙共振模態，能有效的增加 低頻頻寬，達成涵蓋GSM850/900/1800/1900/UMTS之需求。 200937734 【實施方式】 第1圖為本發明天線之一實施例結構圖，包含：一介 質基板11 ; 一接地面12，位於該介質基板1丨上；一輻射金 屬部13，位於該介質基板丨丨上，與該接地面12不互相重疊 ’該輻射金屬部13並包含：一第一金屬部131 ，其一端為 天線饋入點16，該天線饋入點16並大致位於該接地面12之 一邊緣處，其另一端則為開路；一第二金屬部132，其一 端與該第一金屬部131具有一特定間距133，另一端為開 路；及一匹配電路14，位於該介質基板丨丨上，其一端連接 至一信號源15，另一端連接至該天線饋入點16。 第2圖為本發明天線一實施例之返回損失圖。在實施 例中選擇下列尺寸來進行實驗：介質基板丨丨長度約為ιι〇 mm、寬度約為60mm ;接地面12長度約&1〇〇mm、寬度 約為60mm;輻射金屬部13之第一金屬部131 ，其長度= 為76mm、寬度約為3mm ;第二金屬部132，其長^約 為44mm、寬度為不等寬；而第二金屬部132與第一:屬 邛131之特疋間距133約為imm ;匹配電路μ，包含： 第一電感元件3Π(3.3ηΗ);第二電感元件312(56nH);第 一電容7L件321(1.8pF);第二電容元件322 (22pF)。由所 得之實驗結果，在6dB返回損失的定義之下，該第一金屬 邛之低頻共振模態211足以涵蓋GSM85〇/9〇〇頻帶，而唁第 -金屬部之高頻共振模態、212 m同該第二金屬部之共=模 200937734 態22，足以涵蓋GSM1800/1900/UMTS頻帶。 第3圖為本發明天線一實施例之匹配電路等效電路圖 。本實施例所採用之匹配電路14的形式如下：由天線饋入 點16往信號源15觀察，先並聯第一電感元件311，然後再 串聯第一電容元件321 ，接下來並聯第二電感元件312， 最後串聯第二電容元件322，形成一高通形式的匹配電路 14，因此特別適用於針對低頻頻帶作調整，而降低對高頻 〇 頻帶的影響。 第4圖為本發明天線之其他匹配電路等效電路圖。依 照不同阻抗匹配的需求，可以採用不同形式的匹配電路41 ,42, 43以及元件值，達成阻抗匹配的需求，以涵蓋所需的 頻帶。 第5圖為本發明天線之其他實施例5，包含：一介質 基板11 ; 一接地面12，位於該介質基板11上；及一輻射金 ® 屬部53，位於該介質基板11上，與該接地面12不互相重疊 ，該輻射金屬部53並包含：一第一金屬部531 ，其一端為 天線饋入點16，該天線饋入點16並大致位於該接地面12之 一邊緣處，另一端則為開路；一第二金屬部532，其一端 與該第一金屬部531具有一特定間距533，另一端為開路 。在實施例5中，欲涵蓋之頻帶範圍為GSM900/1800/1900/ UMTS，藉由單一低頻共振模態（第一金屬部之低頻共振 9 200937734 模態611)即可涵蓋GSM900頻帶，因此不需加入匹配電路 來形成雙共振模態。 第6圖為本發明天線之其他實施例5之返回損失圖。 在此實施例中選擇下列尺寸進行實驗：介質基板11長度約 為115 mm、寬度約為60 mm ;接地面12長度約為100 mm、 寬度約為60 mm ;輻射金屬部53之第一金屬部531，其長 度約為85 mm、寬度約為5 mm ;第二金屬部532，其長 度約為44mm、寬度為不等寬；而第二金屬部532與第一 金屬部531之特定間距533約為1mm。由所得之實驗結 果，在6dB返回損失的定義之下，該第一金屬部之低頻共 振模態611足以涵蓋GSM900頻帶，而該第一金屬部之高 頻共振模態612協同該第二金屬部之共振模態62，足以涵 蓋 GSM1800/1900/UMTS 頻帶。 以上說明中所述之實施例僅為說明本發明之原理及其 功效，而非限制本發明。因此，習於此技術之人士可在不 違背本發明之精神對上述實施例進行修改及變化。本發明 之權利範圍應如後述之申請專利範圍所列。 【圖式簡單說明】 第1圖為本發明天線一實施例結構圖。 第2圖為本發明天線一實施例之返回損失圖。 第3圖為本發明天線一實施例之匹配電路等效電路圖。 200937734 第4圓為本㈣天線之其純配電料效電路圖 第5圖為本發明天線之其他實施例。 第6圖為本發明天線之其他實施例之返回損失圖 【主要元件符號說明】 11 :介質基板 12 接地面 13,53 ® 131,531 132.532 133.533 輻射金屬部 第一金屬部 第二金屬部 特定間距 14 15 16 匹配電路 信號源 天線饋入點 ❹ 211，611 212,612 22, 62 第一金屬部之低頻共振模態 第一金屬部之高頻共振模態 第二金屬部之共振模態 311 312 321 322 第一電感元件 第二電感元件 第一電容元件 第二電容元件 11 200937734 33 41,42,43 5 :匹配電路與接地面之短路點 :本發明天線之其他匹配電路等效電路圖 :本發明天線之其他實施例200937734 IX. INSTRUCTIONS: TECHNICAL FIELD OF THE INVENTION The present invention relates to a monopole antenna, and more particularly to a multi-frequency grass antenna suitable for use in a line communication device. [Prior Art] With the rapid development of the wireless communication industry, it has become a popular situation of human-powered devices. The design of mobile phones is still demanding light, thin, short, and small, and the demand in the communication band has been From the original dual-band operation to multi-frequency operation (four-frequency operation or five-frequency operation), the wireless communication service that the mobile phone can provide is more diversified. The design of the multi-frequency antenna is roughly divided into two antenna designs and a single wide-band antenna. The former inevitably causes the planning of the antenna placement, the antenna fabrication cost, and the electromagnetic interference. The latter enables the internal space to be effective. The cost can also be reduced. Therefore, designing a single antenna with multi-band operation characteristics is a better solution. However, the development of antenna wideband mechanism and technology will be another challenge, so the antenna design needs to find a broadband solution to meet the needs of multi-band operation. 2. Taiwan Patent Publication No. 541,759 "Folding Dual-Frequency Monopole Antenna", Taiwan Patent Publication No. 1221,042 "Plane Multi-Frequency Monopole Antenna" and Kouwan Patent Announcement No. 1234,9〇2 No. "Tri-band printed circuitary single-pole antenna" adopts a single-feed multi-branch monopole antenna to achieve multi-frequency 5 200937734 operation. However, the multiple branches of the antenna design have great influence on each other. In addition, it is necessary to consider the influence of the coupling of the ends of the branches, especially the resonance modes of the similar frequency of each branch, which increases the complexity of the design. In order to solve the above problems, we propose a multi-frequency monopole antenna, the added branch has a specific spacing from the original branch, and electromagnetic resonance is used to generate resonance, so the increased resonant mode and original The modalities with similar frequencies have little influence on each other's ability to cover a large operating bandwidth by using the increased resonant mode combined with the original modality without any concern about whether or not it affects the original modality. In other words, the advantage of each branch is that it has the characteristics of independent operation, which can effectively reduce the complexity of the antenna design and the time required for the design. Furthermore, an appropriate matching circuit can be added to improve the impedance matching, and the real part of the impedance and the imaginary part of the impedance can be adjusted by the parallel elements, and the imaginary part of the impedance can be adjusted by the series element to obtain the appropriate impedance real part with the double imaginary zero point. The original single resonance mode is increased to a double resonance mode, thereby achieving a wider frequency operation. SUMMARY OF THE INVENTION As described above, it is an object of the present invention to provide a multi-frequency monopole antenna design suitable for mobile communication devices, which can cover GSM850/900/1800/1900/UMTS (824-894 MHz/890-960 MHz) Operation of the /1710 - 1880 MHz/1850 -1990 MHz/1920-2170 MHz) band. The antenna of the present invention comprises: a dielectric substrate, a ground plane, a radiation 200937734 metal portion and a matching circuit. The ground plane is on the dielectric substrate. The radiant metal portion is located on the dielectric substrate and does not overlap with the ground plane. The conditioned metal portion includes: a - metal portion, one end of which is an antenna feed point, and the antenna feed point is substantially at the connection At one edge of the ground, the other end is an open circuit; a second metal portion has one end having a specific spacing (less than 3 mm) from the first metal portion and an open end at the other end. The matching circuit is located on the δ-substrate substrate, one end of which is connected to a signal source, and the other end is connected to the δ-Hai antenna feed point. The dielectric substrate can be a system board of a mobile communication device, and the ground plane can be formed on the dielectric substrate using printing or etching techniques. The radiant metal portion can be formed on the dielectric substrate using printing or etching techniques, or can be formed by stamping or cutting a metal sheet. In the antenna of the present invention, the first metal portion resonates with a quarter-wave mode (operating at about 900 MHz) and a frequency doubling mode (operating at about 2200 MHz) plus a second metal portion. With this particular spacing, the first metal portion is electromagnetically coupled to resonate with its quarter-wave mode (operating at approximately 175 〇 ® MHz)' to cover GSM900/1800/1900/UMTS operation. Next, an appropriate matching circuit is added, in which a high-pass type matching circuit is included, including at least one shunt inductor and at least one series capacitor, which functions to reduce the influence on the high-frequency mode, and can be improved for low-frequency impedance matching. After selecting the appropriate component values, use the appropriate real impedance matching the double imaginary zero to increase the low frequency from a single resonant mode to a double resonant mode, which can effectively increase the low frequency bandwidth to reach GSM850/900/1800. /1900/UMTS requirements. 200937734 [Embodiment] FIG. 1 is a structural diagram of an embodiment of an antenna according to the present invention, comprising: a dielectric substrate 11; a ground plane 12 on the dielectric substrate 1; and a radiation metal portion 13 on the dielectric substrate. The radiant metal portion 13 includes a first metal portion 131, one end of which is an antenna feed point 16, and the antenna feeds the point 16 and is located substantially at the ground plane 12 An edge is open at the other end; a second metal portion 132 has a specific spacing 133 from one end of the first metal portion 131 and an open circuit at the other end; and a matching circuit 14 is disposed on the dielectric substrate Up, one end is connected to a signal source 15 and the other end is connected to the antenna feed point 16. Figure 2 is a diagram showing the return loss of an embodiment of the antenna of the present invention. In the examples, the following dimensions were selected for the experiment: the dielectric substrate has a length of about ιι〇mm and a width of about 60 mm; the ground plane 12 has a length of about & 1 mm and a width of about 60 mm; and the radiant metal portion 13 a metal portion 131 having a length of 76 mm and a width of about 3 mm; a second metal portion 132 having a length of about 44 mm and a width of unequal width; and the second metal portion 132 and the first portion:疋 spacing 133 is about imm; matching circuit μ, comprising: first inductance element 3Π (3.3ηΗ); second inductance element 312 (56nH); first capacitance 7L piece 321 (1.8pF); second capacitive element 322 (22pF ). From the experimental results obtained, under the definition of 6dB return loss, the low frequency resonance mode 211 of the first metal 足以 is sufficient to cover the GSM85〇/9〇〇 band, and the high frequency resonance mode of the first metal portion, 212 m is the same as the common mode = 200937734 state 22 of the second metal portion, sufficient to cover the GSM 1800/1900/UMTS band. Figure 3 is an equivalent circuit diagram of a matching circuit of an embodiment of the antenna of the present invention. The matching circuit 14 used in this embodiment has the following form: as viewed from the antenna feeding point 16 to the signal source 15, the first inductive component 311 is connected in parallel, then the first capacitive component 321 is connected in series, and then the second inductive component 312 is connected in parallel. Finally, the second capacitive element 322 is connected in series to form a matching circuit 14 in a high-pass form, and thus is particularly suitable for making adjustments to the low frequency band and reducing the influence on the high frequency chirp band. Figure 4 is an equivalent circuit diagram of other matching circuits of the antenna of the present invention. Depending on the requirements of the different impedance matching, different forms of matching circuits 41, 42, 43 and component values can be used to achieve impedance matching requirements to cover the desired frequency band. 5 is another embodiment 5 of the antenna of the present invention, comprising: a dielectric substrate 11; a ground plane 12 on the dielectric substrate 11; and a radiation gold® portion 53 on the dielectric substrate 11, and The grounding surfaces 12 do not overlap each other. The radiating metal portion 53 includes: a first metal portion 531 having an antenna feeding point 16 at one end thereof, and the antenna feeding point 16 is located substantially at one edge of the grounding surface 12, and One end is an open circuit; a second metal portion 532 has a specific spacing 533 at one end and the first metal portion 531, and the other end is an open circuit. In the embodiment 5, the frequency band to be covered is GSM900/1800/1900/UMTS, and the GSM900 band can be covered by a single low-frequency resonance mode (the low-frequency resonance of the first metal portion 9 200937734 modal 611), so A matching circuit is added to form a dual resonant mode. Figure 6 is a diagram showing the return loss of another embodiment 5 of the antenna of the present invention. In this embodiment, the following dimensions were selected for the experiment: the dielectric substrate 11 has a length of about 115 mm and a width of about 60 mm; the ground plane 12 has a length of about 100 mm and a width of about 60 mm; and the first metal portion of the radiating metal portion 53 531, which has a length of about 85 mm and a width of about 5 mm; the second metal portion 532 has a length of about 44 mm and a width that is unequal; and the second metal portion 532 has a specific spacing 533 from the first metal portion 531. It is 1mm. From the experimental results obtained, under the definition of 6dB return loss, the low frequency resonant mode 611 of the first metal portion is sufficient to cover the GSM900 band, and the high frequency resonant mode 612 of the first metal portion cooperates with the second metal portion. The resonant mode 62 is sufficient to cover the GSM1800/1900/UMTS band. The embodiments described in the above description are merely illustrative of the principles of the invention and its advantages, and are not intended to limit the invention. Therefore, those skilled in the art can make modifications and changes to the above embodiments without departing from the spirit of the invention. The scope of the invention should be as set forth in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a structural view showing an embodiment of an antenna according to the present invention. Figure 2 is a diagram showing the return loss of an embodiment of the antenna of the present invention. Fig. 3 is an equivalent circuit diagram of a matching circuit of an embodiment of the antenna of the present invention. 200937734 The fourth circle is the (four) antenna of its pure power distribution efficiency circuit diagram. Figure 5 is another embodiment of the antenna of the present invention. Figure 6 is a return loss diagram of another embodiment of the antenna of the present invention. [Main component symbol description] 11: dielectric substrate 12 ground plane 13, 53 ® 131, 531 132.532 133.533 radiation metal portion first metal portion second metal portion specific pitch 14 15 16 Matching circuit signal source antenna feeding point 211 211, 611 212, 612 22, 62 Low frequency resonant mode of the first metal part High frequency resonant mode of the first metal part Resonance mode of the second metal part 311 312 321 322 First Inductor element second inductance element first capacitance element second capacitance element 11 200937734 33 41,42,43 5 : short circuit point of matching circuit and ground plane: other matching circuit equivalent circuit diagram of antenna of the invention: other implementation of antenna of the invention example
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