201036254 六、發明說明： _ _ 【發明所屬之技術領域】 本發明係關於一種開路槽孔天線（〇Pen_end slot antenna)，尤指一種利用短槽孔接近開路端的兩側各連接一 負載電容到饋入線所完成之小於或等於八分之一波長的短 開路槽孔天線。 【先前技術】 隨著無線通訊的蓬勃發展，現今通訊產品趨向輕薄短 〇 小的發展趨勢，當單一無線通訊產品只有一個系統時，其 內部的電路密度相當的高，相對而言天線所佔用的空間也 就被嚴格地侷限住。此外，，倘若數個通訊系統存在於同一 產品中，例如：數位電視（Digital Television, DTV)、無線 區域網路（WLAN)、全球定位系統（Global Positioning System, GPS)等；或是多輸入多輸出（MultiplelnputMultipleOutput， ΜΙΜΟ)系統與分集天線（Antenna Diversity)的應用上，此時 便需要複數個操作，因此天線可使用的空間也相對越來越 〇 小。故如何在有限的空間下，完成天線的設計，縮小化與 模組化便成爲現今重要的設計重點。 傳統開路槽孔天線，其架構圖如第1 a圖所示，其係顯 示習知四分之一波長的開路槽孔天線架構圖，圖中黑色細 線爲一 50歐姆的微帶線（microstrip line)作爲訊號饋入，此 微帶線製作於電路板的某一面，而灰色區塊則爲接地平 面，製作於電路板的另一面，並於接地平面邊緣處挖空某 一導體區域以形成一開路槽孔，並使其與微帶線垂直配 -4- 201036254 置。其中槽孔右側爲開跆端’，而左側則爲短路端，利用微 帶線末端一小段開路株（Open Stub)長度1τ，以及此微帶饋 入線與槽孔右側開路端的距離1m，來達成良好的天線阻抗 匹配。此種類型槽孔天線的操作頻率，是由橫向的槽孔長 度決定 '而所需長度一般爲共振頻率的四分之一波長。以 9mm長度的槽孔天線爲例，其模擬與量測的反射損失 (Return Loss)與頻率響應，如第lb圖所示，其係顯示習知 四分之一波長的開路槽孔天線的反射損失與頻率響應圖。 0 其中實線爲量測結果，而方形標記虛線則爲Ansoft High Frequency Structure Simulator (HFSS)之全波模擬結果。如 第lb圖中所示，天線的操作頻率爲4.8 GHz，此時所選擇的 槽孔長度約爲共振頻率的四分之一波長。 此外，2000年3月7日公告之第6,034,644號美國專利 係提出以微帶線饋入之U形槽孔天線，並使用電容性耦合 之島狀金屬導體（island conductor)來改變槽孔共振頻率，達 成頻率可調之目的。然而此種架構所能縮小的能力有限， 相對於本發明所能縮小50%以上的能力來說（稍後敘明），其 於現今通訊產品中欠缺實用性。 另一習知技術，爲E. J. Kim等人於2007年11月在 Microwave Conference Korea-Japan 中所揭露之「Compact meander slot antenna with open-ends」之架構，此習知技術 所提出之天線架構爲一具有兩開路端之蜿蜒槽孔天線’且 此槽孔天線爲傳統的四分之一波長之開路槽孔天線’其係 利用蜿蜒（meander)的方式來縮小所佔面積。然而此種架構 下，該槽孔之總長度仍爲操作頻率的四分之一波長，故其 201036254 縮小的幅度有限，且所佔面'積仍然很大。因此就實際應用 上而言，此習知技術所帶來的實用性並不高。 此外，Maximilian C. Scardelletti 等人於 2008 年 1 月在 在 中所揭露之「Electrically small folded slot antenna utilizing capacitive loaded slot lines」 之架構，此習知技術提出在彎折槽孔天線（folded slot antenna)的兩端加入晶片電容負載的方式來實現槽孔天線 縮小化的成效。然其所提出的架構，僅將未加入晶片電容 〇 負載槽孔天線的面積縮小2 2 %，相較於本發明所能縮小5 0 % 面積來說（稍後敘明），其所佔面積仍然過大，故此習知技 > 術在縮小元件尺寸方面並無太大的貢獻。 有鑑於上述習知槽孔天線架構能縮小之幅度有限，致 使所佔面積相對過大等缺失，故本發明在此提出一種具有 複數負載電容結構之短開路槽孔天線，藉由改變該等負載 電容値，達成頻率可調的功能，並可大幅縮小天線尺寸（小 於八分之一波長共振或是等於八分之一波長共振之槽孔天 〇 線）。 【發明内容】 本發明之主要目的係提供一種短開路槽孔天線，藉由 負載電容的加入’可使得原本操作於四分之一波長共振之 槽孔天線，降低爲低於八分之一波長共振的槽孔天線，以 完成天線縮小化的具體功效，進而增加實際應用的範圍。 本發明之再一目的係提供一種短開路槽孔天線，藉由 變容器的加入’完成小於八分之一波長的短槽孔天線設 201036254 計，並能達成頻率可調之功’能。 本發明之另一目的係提供一種不會因爲接地面尺寸改 變而影響天線特性之八分之一波長短開路槽孔天線，其具 有相當穩定的特性。 爲達到上述目的，本發明提供一種八分之一波長短開 路槽孔天線，其包含：一饋入線；一接地平面，與該饋入 線分別印製於電路之兩面；一短槽孔，藉由將該接地平面 之一邊緣向內控空一導體區域而形成；以及兩負載電容， ^ 各自連接該饋入線至該短槽孔接近一開路端之兩側。 如所述之短開路槽孔天線，其中該饋入線其中該饋入 線爲微帶線或同軸纜線。 如所述之短開路槽孔天線，其中該短槽孔係於一片金 屬片之邊緣處製作。 如所述之短開路槽孔天線，其中藉由改變該等負載電 容之電容値，可實現小於或等於八分之一波長共振的槽孔 天線。 如所述之短開路槽孔天線，其中該負載電容可爲晶片 ❾ 電容或印刷式電容。 如所述之短開路槽孔天線，其中該等負載電容可以變 容器來取代。 如所述之短開路槽孔天線，其中當以變容器作爲該等 負載電容時，藉由改變其輸入偏壓値來改變該八分之一波 長短開路槽孔天線之操作頻率。 如所述之負載電容降低槽孔天線操作頻率之技術’可 適用於半波長共振之槽孔天線。 如所述之短開路槽孔天線可應用於USB dongle、 201036254 PCMCIA卡、WLAN卡、’WihAX產品、筆記型電腦之內藏 式天線以及手機天線。 本發明之目的以及所達成的效果，可經由下列實施方 式得到更深入的了解。 【實施方式】 以下關於本發明之說明僅是舉例’目的在使熟知本領 域之人士充分瞭解，而非用於限制本發明。 以下結合實施例對本發明之具體實施方案進行詳細之 〇 說明。 首先，請參考第2a及2b圖’其係顯示本發明第一實 施例之短開路槽孔天線結構圖及其等效電路模型，其中該 短開路槽孔天線之槽孔長度與寬度分別爲9mm與1.5mm、 接地平面大小爲65mmx42mm，且槽孔配置於該接地平面之 長邊邊緣中心處。此短開路槽孔天線係以第la圖中所示之 習知四分之一波長的開路槽孔天線爲基礎，進而在短槽孔 接近開路端的兩側，各連接一負載電容（亦即CM1、CM2)到 © 饋入線，使其能在不改變習知四分之一波長槽孔長度的條 件下，降低天線操作頻率，達成縮小化之成效。 如第2b圖所示，此等效電路模型與天線結構的對應關 係爲：一段長度θπ的傳輸線代表從饋入點到槽孔開路端的 距離，而長度esc的傳輸線代表從饋入點到槽孔短路端的距 離，RA與Ca則是爲了滿足寬頻段等效天線輸入阻抗實部的 部份，可對應到天線的輻射電阻。ΚΜ1、C2 = CM2，Ls則爲 對應到微帶饋入線跨過槽孔的寄生電感效應。在此須注意 的是，所加入之該等負載電容可以晶片電容或是印刷式電 201036254 容來實現。 | ‘ 接著參照第3a與3b圖，其係顯示全波軟體與等效電 路模擬之比較結果，其中第3a圖爲一天線輸入阻抗與頻率 響應圖，實線與虛線分別表示全波軟體的模擬結果，而三 角形與方形標記線則爲等效電路模型的模擬結果；第3b圖 爲藉由反射損失與頻率響應顯示全波軟體與等效電路之模 擬結果，實線爲量測結果，虛線則爲全波軟體模擬結果。 由第3a圖模擬結果可知，該天線在2.45GHz時確實有一共 振產生。相較於第lb圖可清楚發現到，藉由加入兩個負載 0 電容所呈現之第3b圖確實可在不改變槽孔長度下，將原本 共振於4.8 GHz之操作頻率的天線，降低爲2.45GHz，進而 達成縮小化之成效，且槽孔長度小於共振頻率（2.45GHz) 的八分之一波長，其中此等效電路之元件値爲：θπ = 〇°、 0sc = 39° ' Ra = 65 0Q > CA = 0.12pF、Ls = 0.5nH、C1 = 2.35pF 以及 C2 = 0.63pF。此外，在此採用Murata公司所生產的表面粘著 元件（Surf ace-Mount Device，S M D)晶片電容的集總電容方式 來實現，其中CMI = 2.2pF且CM2 = 0.6pF，並利用一50歐姆同 軸電纜線（Coaxial Cable)饋入以便量測。量測所得的l〇dB Q 阻抗頻寬有109MHz滿足無線區域網路（WLAN)或是藍芽 (Blue Tooth)通訊應用所需的頻寬（83MHz，2.4~2.4853 GHz)。 第4圖爲本發明第一實施例所測得之天線輻射場型， 其中實線爲E_phi，虛線爲E-theta。由第4圖之量測結果可 知，在x-z平面上，天線爲一全向性的輻射場型，最大天 線增益爲1 .89dBi，故其顯示良好的輻射特性。 第5a圖爲本發明第二實施例之短開路槽孔天線分別應 用於一般USB Dongle (A類）、PCMCIA卡（B類）以及筆記型 電腦（C類）三種不同尺寸的接地面之示意圖，其中，槽孔長 201036254 度與晶片電容値皆相同；_第’5b圖則爲第5a圖中之三種應 用的量測結果，其中，點線爲A類，實線爲B類且虛線爲 C類。由量測結果可知，本發明所提出的短開路槽孔天線 不會因爲接地面尺寸改變而影響天線特性，故本發明具有 相當穩定的特性。 第6a圖爲本發明第三實施例之短開路槽孔天線，其 中，將晶片電容以變容器來代替，故透過不同偏壓將可改 變該變容器之電容値，進而達成頻率可調的功效；第6b圖 ^ 係顯示不同的電容値的反射損失，從圖中可知，當電容値 〇 增加時，則操作頻率降低，因此只要適度地改變電容値， 便可在相同槽孔長度情形下，讓天線能操作於 1.64 GHz〜3.5 GHz之間，達成頻率可調的功用。此外，當天 線操作於1.64GHz時，其槽孔長度僅爲空氣中波長的5%。 最後參照第7圖，其係顯示本發明第三實施例中使用 不同電容値所測得之天線輻射場型，其中實線爲天線操作 於3.5GHz，中心線爲2.45GHz，虛線爲1.9GHz以及點線爲 ^ 1.64GHz的輻射場型。由第7圖之量測結果可知，在x-z平 〇 面上，電容値不同而共振在不同頻率下，其輻射場型之形 狀相似，顯示此天線具有穩定的輻射特性。 綜上所述，本發明提供了一種八分之一短槽孔天線， 其尺寸小於傳統四分之一波長開路槽孔天線的50%以上， 除能大幅縮小天線尺寸之外，並具有簡單架構的特色，容 易與電路整合，進而提高其應用範圍，如：USB dongle、 PCMCIA卡、WLAN卡、WiMAX產品、筆記型電腦之內藏 式天線以及手機天線等，具有實用性及創造性，因此本發 明能有效改善習知技藝之缺失，進而達成發展本發明之目 -10- 201036254 的。 .. 本發明得由熟悉本技藝之人士任施匠思而爲諸般修 飾’然皆不脫如附申請專利範圍所欲保護者。 【圖式簡單說明】 第1 a圖係顯示習知四分之—波長的開路槽孔天線架構 圖， 第lb圖係顯示習知四分之一波長的開路槽孔天線的反 射損失與頻率響應圖； 〇 第2a圖係根據本發明第一較佳實施例顯示短開路槽孔 天線之結構圖； 第2b圖’係顯示本發明第一較佳實施例之短開路槽孔 天線之等效電路模型； 第3 a圖係根據本發明第—較佳實施例藉由天線輸入阻 抗與頻率響應顯示全波軟體與等效電路之模擬結果； 第3b圖係根據本發明第一較佳實施例藉由反射損失 與頻率響應顯示全波軟體與等效電路之模擬結果； 〇 第4圖係根據本發明第一較佳實施例顯示所量測之天 線輻射場型； 第5a圖係根據本發明第二較佳實施例顯示三種短開路 槽孔天線之币意圖； 第5 b圖係根據本發明第二較佳實施例藉由反射損失 與頻率響應顯示量測第5a圖中之短開路槽孔天線之比較結 果； 第6a圖係根據本發明第三較佳實施例顯示短開路槽孔 -11- 201036254 天線之示意圖； 第6b圖係根據本發明第三較佳實施例藉由反射損失 與頻率響應顯示量測第6a圖中之短開路槽孔天線之比較結 果；以及 第7圖係根據本發明第三較佳實施例顯示使用不同電 容値量測所得到之天線輻射場型。 【主要元件符號說明】 〇 〇201036254 VI. Description of the invention: _ _ [Technical field of the invention] The present invention relates to an open slot antenna (〇Pen_end slot antenna), and more particularly to a load capacitor to a connection on both sides of a short slot close to an open end A short-open slot antenna that is less than or equal to one-eighth of the wavelength completed by the incoming line. [Prior Art] With the rapid development of wireless communication, today's communication products tend to be thin, light and small. When a single wireless communication product has only one system, its internal circuit density is quite high, relatively speaking, the antenna occupies Space is also strictly limited. In addition, if several communication systems exist in the same product, such as: Digital Television (DTV), Wireless Local Area Network (WLAN), Global Positioning System (GPS), etc.; or multiple inputs In the application of the (MultiplelnputMultipleOutput, ΜΙΜΟ) system and the diversity antenna (Antenna Diversity), a plurality of operations are required at this time, so the space available for the antenna is relatively smaller. Therefore, how to complete the design, reduction and modularization of the antenna in a limited space has become an important design focus today. The traditional open-channel slot antenna has an architectural diagram as shown in Figure 1a. It shows a schematic diagram of a known quarter-wavelength open-cell slot antenna. The black thin line is a 50 ohm microstrip line. As a signal feed, the microstrip line is formed on one side of the circuit board, and the gray block is a ground plane, which is formed on the other side of the circuit board, and a certain conductor area is hollowed out at the edge of the ground plane to form a Open the slot and make it perpendicular to the microstrip line -4- 201036254. The right side of the slot is the open end', and the left side is the short-circuit end. The length of the open Stub of the microstrip line is 1τ, and the distance between the microstrip feed line and the open end of the right side of the slot is 1m. Good antenna impedance matching. The operating frequency of a slot antenna of this type is determined by the length of the slot in the transverse direction. The required length is typically a quarter of the wavelength of the resonant frequency. Taking a slot antenna of 9 mm length as an example, the return loss and frequency response of the simulation and measurement, as shown in Fig. lb, show the reflection of a conventional quarter-wave open-cell slot antenna. Loss and frequency response map. 0 The solid line is the measurement result, and the square mark dashed line is the full wave simulation result of Ansoft High Frequency Structure Simulator (HFSS). As shown in Figure lb, the antenna operates at a frequency of 4.8 GHz, at which point the selected slot length is approximately one quarter of the resonant frequency. In addition, U.S. Patent No. 6,034,644, issued Mar. 7, 2000, discloses a U-shaped slot antenna fed by a microstrip line and uses a capacitively coupled island conductor to change the slot resonance frequency. , to achieve the purpose of frequency adjustment. However, the ability of such an architecture to be reduced is limited, and it is less useful in today's communication products than the ability of the present invention to reduce by more than 50% (described later). Another conventional technique is the "Compact meander slot antenna with open-ends" architecture disclosed by EJ Kim et al. in Microwave Conference Korea-Japan in November 2007. The antenna architecture proposed by the prior art is one. A slotted antenna with two open ends, and the slot antenna is a conventional quarter-wave open-cell slot antenna, which uses a meander to reduce the area occupied. However, in this architecture, the total length of the slot is still a quarter of the operating frequency, so the 201036254 reduction is limited and the area of the surface is still large. Therefore, in practical applications, the practicality brought by this prior art is not high. In addition, the structure of "Electrically small folded slot antenna utilizing capacitive loaded slot lines" disclosed by Maximilian C. Scardelletti et al. in January 2008, which is proposed in a folded slot antenna The two ends of the chip are added to the capacitive load of the chip to achieve the effect of narrowing the slot antenna. However, the proposed architecture only reduces the area of the antenna capacitor-free load slot antenna by 22%, which is smaller than the area of the invention that can be reduced by 50% (described later). It is still too large, so the conventional technique does not contribute much to reducing the size of components. In view of the above-mentioned conventional slot antenna architecture, the limited size of the slot antenna structure is limited, and the occupied area is relatively large and so on. Therefore, the present invention proposes a short open slot slot antenna having a complex load capacitance structure, by changing the load capacitance.値, the frequency-adjustable function is achieved, and the antenna size can be greatly reduced (less than one-eighth wavelength resonance or a slotted antenna line equal to one-eighth wavelength resonance). SUMMARY OF THE INVENTION The main object of the present invention is to provide a short-opening slot antenna, which can reduce the slot antenna originally operated in quarter-wave resonance to less than one-eighth wavelength by adding load capacitance. Resonant slot antennas to complete the specific effects of antenna reduction, thereby increasing the range of practical applications. A further object of the present invention is to provide a short-open slot antenna that can be used to achieve a frequency-tunable capability by adding a short-slot antenna of less than one-eighth wavelength by the addition of a varactor. Another object of the present invention is to provide an eighth-wavelength short-opening slot antenna that does not affect the antenna characteristics due to changes in the size of the ground plane, and which has relatively stable characteristics. To achieve the above object, the present invention provides an eighth-wavelength short-opening slot antenna comprising: a feed line; a ground plane printed on both sides of the circuit and the feed line; a short slot Forming one edge of the ground plane inward to control a conductor region; and two load capacitors, ^ respectively connecting the feed line to the short slot to be close to an open end. A short open slot antenna as described, wherein the feed line is the microstrip line or coaxial cable. A short open slot antenna as described, wherein the short slot is formed at the edge of a piece of metal. A short open slot antenna as described, wherein a slot antenna less than or equal to one eighth of a wavelength resonance can be achieved by varying the capacitance of the load capacitors. A short open slot antenna as described, wherein the load capacitance can be a chip ❾ capacitor or a printed capacitor. A short open slot antenna as described, wherein the load capacitance can be replaced by a variable container. A short open slot antenna as described, wherein when the varactor is used as the load capacitance, the operating frequency of the one-eighth long open slot antenna is changed by changing its input bias 値. The technique of reducing the operating frequency of the slot antenna as described in the load capacitance can be applied to a slot antenna having a half-wavelength resonance. The short open slot antenna as described can be applied to USB dongle, 201036254 PCMCIA card, WLAN card, 'WihAX product, built-in antenna for notebook computer and mobile phone antenna. The object of the present invention and the effects achieved can be further understood by the following embodiments. The following description of the present invention is intended to be illustrative only, and is not intended to limit the invention. The specific embodiments of the present invention will be described in detail below with reference to the embodiments. First, please refer to FIGS. 2a and 2b, which show a short open-channel slot antenna structure diagram and an equivalent circuit model thereof according to the first embodiment of the present invention, wherein the slot length and width of the short-open slot slot antenna are respectively 9 mm. With a size of 1.5 mm, the ground plane is 65 mm x 42 mm, and the slot is disposed at the center of the long edge of the ground plane. The short-open slot antenna is based on the conventional quarter-wave open-cell slot antenna shown in FIG. 1A, and further connected to a load capacitor (ie, CM1) on both sides of the short slot near the open end. CM2) to the © feed line, which can reduce the operating frequency of the antenna without changing the length of the known quarter-wave slot, and achieve the effect of downsizing. As shown in Fig. 2b, the correspondence between the equivalent circuit model and the antenna structure is: a transmission line of length θπ represents the distance from the feed point to the open end of the slot, and a transmission line of length esc represents the point from the feed point to the slot. The distance between the short-circuit ends, RA and Ca, is to meet the real part of the wide-band equivalent antenna input impedance, which can correspond to the radiation resistance of the antenna. ΚΜ1, C2 = CM2, and Ls is the parasitic inductance effect corresponding to the microstrip feed line across the slot. It should be noted that the added load capacitance can be realized by chip capacitor or printed circuit. | ' Then refer to the 3a and 3b diagrams, which show the comparison of the full-wave software and the equivalent circuit simulation. The 3a is an antenna input impedance and frequency response diagram, and the solid and dashed lines respectively represent the simulation of the full-wave software. As a result, the triangle and square mark lines are the simulation results of the equivalent circuit model; the third picture shows the simulation results of the full-wave software and the equivalent circuit by the reflection loss and the frequency response, the solid line is the measurement result, and the broken line is Simulated results for full wave software. It can be seen from the simulation results in Fig. 3a that the antenna does have a resonance at 2.45 GHz. Compared with the lb diagram, it can be clearly seen that the 3b diagram presented by adding two load 0 capacitors can reduce the antenna that originally resonates at the operating frequency of 4.8 GHz to 2.45 without changing the slot length. GHz, which achieves the effect of downsizing, and the slot length is less than one-eighth of the wavelength of the resonant frequency (2.45 GHz), where the component of the equivalent circuit is: θπ = 〇°, 0sc = 39° ' Ra = 65 0Q > CA = 0.12pF, Ls = 0.5nH, C1 = 2.35pF, and C2 = 0.63pF. In addition, this is achieved by using the lumped capacitance method of Murate's Surface Acoustic Device (SMD) chip capacitors, where CMI = 2.2pF and CM2 = 0.6pF, and a 50 ohm coaxial is utilized. A Coaxial Cable is fed in for measurement. The measured l〇dB Q impedance bandwidth has 109MHz to meet the bandwidth (83MHz, 2.4~2.4853 GHz) required for wireless local area network (WLAN) or Bluetooth (Blue Tooth) communication applications. Fig. 4 is a view showing the antenna radiation field measured by the first embodiment of the present invention, wherein the solid line is E_phi and the broken line is E-theta. From the measurement results in Fig. 4, it is known that the antenna is an omnidirectional radiation pattern on the x-z plane, and the maximum antenna gain is 1.89 dBi, so it exhibits good radiation characteristics. FIG. 5a is a schematic diagram of a short-opening slot antenna according to a second embodiment of the present invention applied to three different sizes of ground planes of a general USB Dongle (Class A), a PCMCIA card (Class B), and a notebook computer (Class C). Among them, the slot length is 201036254 degrees and the chip capacitance is the same; _ '5b diagram is the measurement results of the three applications in Figure 5a, where the dotted line is class A, the solid line is class B and the dotted line is C class. It can be seen from the measurement results that the short-opening slot antenna proposed by the present invention does not affect the antenna characteristics due to the change in the size of the ground plane, so the present invention has quite stable characteristics. FIG. 6a is a short-opening slot antenna according to a third embodiment of the present invention, wherein the chip capacitor is replaced by a variable container, so that the capacitance 値 of the varactor can be changed by different bias voltages, thereby achieving frequency-adjustable efficiency. Fig. 6b shows the reflection loss of different capacitances. As can be seen from the figure, when the capacitance 値〇 increases, the operating frequency decreases. Therefore, as long as the capacitance 适 is changed moderately, the same slot length can be used. Allow the antenna to operate between 1.64 GHz and 3.5 GHz for frequency-adjustable functions. In addition, when the line operates at 1.64 GHz, the slot length is only 5% of the wavelength in the air. Finally, referring to FIG. 7, which shows an antenna radiation pattern measured by using different capacitances in the third embodiment of the present invention, wherein the solid line is an antenna operating at 3.5 GHz, a center line of 2.45 GHz, a dotted line of 1.9 GHz, and The dotted line is a radiation field type of 1.64 GHz. From the measurement results in Fig. 7, it can be seen that on the x-z plane, the capacitance is different and the resonance is at different frequencies, and the shape of the radiation field is similar, indicating that the antenna has stable radiation characteristics. In summary, the present invention provides an eighth-slot short-slot antenna that is smaller than 50% of a conventional quarter-wave open-cell slot antenna, and has a simple architecture in addition to greatly reducing the antenna size. The characteristics are easy to integrate with the circuit, thereby improving its application range, such as: USB dongle, PCMCIA card, WLAN card, WiMAX product, built-in antenna of notebook computer and mobile phone antenna, etc., which has practicality and creativity, so the present invention It can effectively improve the lack of conventional skills, and thus achieve the goal of developing the present invention-10-201036254. The invention is intended to be modified by those skilled in the art and is intended to be modified as described in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1a shows a conventional quarter-wavelength open-cell slot antenna architecture diagram, and Figure lb shows the reflection loss and frequency response of a conventional quarter-wave open-cell slot antenna. Figure 2A is a structural view showing a short-opening slot antenna according to a first preferred embodiment of the present invention; and Figure 2b is an equivalent circuit showing a short-opening slot-hole antenna according to a first preferred embodiment of the present invention; Model 3; Figure 3a shows a simulation result of a full-wave software and an equivalent circuit by an antenna input impedance and a frequency response according to a first preferred embodiment of the present invention; Figure 3b is a diagram of a first preferred embodiment of the present invention. The simulation results of the full-wave software and the equivalent circuit are shown by the reflection loss and the frequency response; FIG. 4 shows the measured antenna radiation pattern according to the first preferred embodiment of the present invention; FIG. 5a is according to the present invention. The second preferred embodiment shows the coin intent of three short-open slot antennas; and FIG. 5b shows the short-open slot antenna in FIG. 5a by reflection loss and frequency response display according to the second preferred embodiment of the present invention. Comparison Figure 6a is a schematic view showing an antenna of a short open slot -11 - 201036254 according to a third preferred embodiment of the present invention; Fig. 6b is a graph showing the amount of reflection loss and frequency response according to the third preferred embodiment of the present invention The comparison results of the short open slot antennas in Fig. 6a are measured; and Fig. 7 shows the antenna radiation pattern obtained using different capacitance measurements according to the third preferred embodiment of the present invention. [Main component symbol description] 〇 〇
-12--12-