1270234 九、發明說明： 【發明所屬之技術領域】 • 本發明係涉及一種雙頻倒F形天線（dual_band inverted-F antenna)，特別是應用於無線通訊產品上之天線。 【先前技術】 '1270234 IX. Description of the Invention: [Technical Field] The present invention relates to a dual-band inverted-F antenna, and more particularly to an antenna for use in a wireless communication product. [Prior Art] '
Ik著近年來無線區域網路（wireless local area network ) 的快速發展，在天線的性能需求上也逐漸提高，不但要求 尺寸的縮小化，且必須具備有内藏式、整合性與多頻帶等 特性，才具有市場競爭力。 目W適用於無線區域網路的電子通訊產品，已有一些 習用的倒F型天線設計，此類設計大多是單頻操作於2.4 GHz頻帶或是可以雙頻操作但在5 σΗζ僅能 她其中-個頻帶，無法完全涵蓋2.4A5GHz盍全頻2帶戈(5包8 含5.2及5.8 GHz頻帶），❿且在雙頻操作部份通常需要兩 個電流路徑來造成雙頻帶操作，如美國專利第6,686 886 號“應用於筆記型電腦上之整合式天線（Integrated antenna for laptop appncations)”其所揭示的是一種 筆記型電腦内的倒F型天線結構，並與螢幕 地面整合的設計，該天線雖有雙頻操作（2.4/5.2 GHz) ’但在5 GHz僅 # ^ π ^ ^匕3 GHz頻平，且其雙 ^作3由不同電流路徑來形成，增加了電路設計 的複雜性。 』电格σ又口卞 【發明内容】 决刖述問題，我們在本發明中提出一種雙頻令 F型天線的創新設計。 裡又茨货 的創丨t發明之目的在於提供—種雙頻倒F型天到 第：二ί一路徑，提供該天線之第-(較低 一 （較阿）共振模態之電流路徑，不僅在第 一“共振模態之頻寬可涵蓋無線區域網路2.4GHz頻 1270234 且在第二（較高）共振模態可產生一具有寬頻的操作 杈態，涵蓋5 GHz全頻帶5.2及5.8 GHz頻帶（包含5.2及5.8 GHz頻帶）。 本發明雙頻倒F形天線結構包括有一接地金屬片、一第 一輻射金屬片、一第二輻射金屬片、一短路金屬臂及一饋 入同軸傳輸線等構件，其中，該接地金屬片包含一短路點 與一接地點；該第一輻射金屬片位於該接地金屬片之一上 端邊緣的上方且大致平行於該接地金屬片的邊緣；該第二 輻射金屬片位於該接地金屬片之上端邊緣上方，其形狀大 致為梯开》，並具有一上邊、一底邊及兩側邊且包含一饋 =點，該上邊與該第一輻射金屬片之末端相連接，使得該 第一輻射金屬片與該第二輻射金屬片形成一共振路徑，用 於產^該天線之第一（較低）及第二（較高）操作頻帶， 在該第二輻射金屬片上設有一饋入點，該饋入點位於底邊 側處，而该第二輻射金屬片的兩側邊則分別與該第一輻射 =屬片夾一傾斜角，用於調整該天線之第一及第二操作頻 帶之頻率比；該短路金屬臂位於該第一輻射金屬片與該接 地金屬片之間，其一端連接至該第二輻射金屬片之該底 邊，另一端則連接至該接地金屬片的短路點；另外，饋入 同軸傳輸線係用以傳輸訊號，該饋入同軸傳輸線包含有一 :心導線及一外層接地導體，其中，該中心導線連接至該 第二輻射金屬片之該饋入點；該外層接地導體則連接至該 接地金屬片之該接地點。 在本發明中，該第-輻射金屬片及該第二輕射金屬片 所形成之總，徑，可提供該天線之第一（較低）共振模態 及第二（較高）共振模態之電流路徑，經實驗得證，將其 路徑總長度設計成約為該第一共振模態中心頻率的1/4波 長、以及該第二共振模態中心頻率的1/2波長，可得最佳的 訊號接收效果。本發明具有以τ的特性：可藉由調整其路 1270234 ^的總長度’來產生雙頻帶操作，並利用改變該短路金屬 =短Ϊ點ί置來得到兩操作頻帶之良好阻抗匹配。同時 Ϊ虚亥f二輻射金屬片之上邊及底邊的長度以及兩側 艿該弟了輻射金屬片所夾的傾斜角，可微調該兩共振模 ::心頻f之頻率比，達到適當的第-（較幻操作頻帶 及弟二（較高）操作頻帶。藉由上述特性，即可設計出適 用於無線區域網路2.4GHz及包含5GHz全鮮（包含5 2 及5.8 GHz頻帶）之雙頻帶操作的倒F型天線。 【實施方式】 如第1圖所示為本發明之雙頻倒F型天線之一實施 例，本發明雙頻倒F型天線丨的結構包括有—接地金屬片 10、一第一輻射金屬片u、一第二輻射金屬片12、一短路 金屬臂13及一饋入同軸傳輸線14等構件，其中，在該接 地金屬片10用以與其他構件連接的邊緣1〇3附近設有一短 路點101與一接地點102，該短路點1〇1則與短路金屬臂 13觸接，而該接地點1〇2則是與外層接地導體ι42觸接； 該第一輻射金屬片11位於該接地金屬片的邊緣1〇3上 方且大致平行於該邊緣103;該第二輻射金屬片12則位於 該接地金屬片10的邊緣103上方，其形狀大致為一梯形， 具有一上邊121、一底邊122及兩側邊123且包含有一饋入 點124，其中該上邊121與該第一輻射金屬片11之末端相 連接’使得該第一輻射金屬片11與該第二輻射金屬片12 形成一共振路徑，用於產生該天線之第一（較低）及第二 (較高）操作頻帶，該饋入點124則位於底邊122侧處， 而該兩側邊123則分別與該第一輻射金屬片11夾一傾斜 角；該短路金屬臂13，位於該第一輻射金屬片U與該接地 金屬片10之間，其一端連接至該第二輻射金屬片12的底 邊122，另一端則連接至該接地金屬片10的短路點101， 用以將該第一輻射金屬片11及該第二輻射金屬片12電氣 1270234 連接至該接地金屬片1 〇，並可微調該天線之第一及第二操 作頻帶之阻抗匹配；另外，該饋入同軸傳輸線14則是用以 傳輸汛號，其結構包含了一中心導線141與一外層接地導 體142，其中，該中心導線141連接至該第二輻射金屬片 Ϊ2的饋入點124 ;該外層接地導體142連接至該接地金屬 片1 〇之該接地點102，如此即完成整個天線構造。 而在本實施例中，該第二輻射金屬片12的上邊121的 長度大於該底邊122的長度，使得該兩側邊123與該第一 輻射金屬片11分別夾有一接近90度且一小於9〇度之傾斜 角，可用於調整該天線之第一及第二操作頻帶之頻率比， 以達成適當之無線區域網路系統頻帶要求。同時在本實施 例中之該接地金屬片10、該第一輻射金屬片u、該第二輻 射金屬片12以及該短路金屬臂13可利用單一金屬片沖壓 (stamping)或切割（cutting)製作而成，或是將談第一輻 射金屬片11、該第二輻射金屬片12以及該短路金屬臂13 以印刷或蝕刻方式形成於一微波基板上，再連接至該接地 金屬片10。 第2圖為本發明天線之一實施例的返回損失實驗結 果；圖中曲線21為該天線之第一（較低）操作頻帶，曲線 22為該天線之第二（較高）操作頻帶，由實驗結果可得到 此一實施例於10 dB返回損失阻抗頻寬定義下，其第一（較 低）操作頻帶21的頻寬可滿足無線區域網路系統於2·4 GHz (2·4-2·5 GHz)之頻帶要求，第二（較高）操作頻帶22 的頻寬可滿足無線區域網路系統於5 GHz (5.15-5.35、 5.725-5.875 GHz)頻帶要求。 第3圖為本發明天線之另一實施例之結構圖，在此實 施例中，該接地金屬片3〇，而在其一邊緣3〇3附近，包含 一短路點301與一接地點3〇2 ;該第一輻射金屬片31，位 於該接地金屬片的邊緣3〇3上方且大致平行於該接地金屬 1270234 片的邊緣303 ;該第二輻射金屬片32，位於該接地金屬片 的邊緣303上方，其形狀大致為一梯形，並具有一上邊32卜 一底邊322及兩側邊323且包含一饋入點324,其中該上邊 321與該苐一輕射金屬片31之末端相連接，使得該第一輕 射金屬片31與該弟一幸S射金屬片32形成一共振路徑，用 於產生該天線之第一（較低）及第二（較高）操作^帶， 該饋入點324則位於該上邊321與該底邊3D之間且靠近 於該底邊322,而該兩側邊323則分別與該第一輕射金屬片 31夾一傾斜角；一短路金屬臂33，位於該第一輕射金屬片 31與該接地金屬片30之間，其一端連接至該第二輻射金屬 片32之該底邊322,另一端則連接至該接地金屬片3〇之該 短路點301，用以將該第一輻射金屬片31及該第二輻射金 屬片32電氣連接至接地金屬片30並可微調該天線之阻抗 匹配；及一饋入同軸傳輸線34，用以傳輸訊號，包含：一 中心導線341，連接至該第二輻射金屬片；32之該饋入點 324 ;及一外層接地導體342，連接至該接地金屬片3〇之該 接地點302。 而在本實施例中，該第二輻射金屬片32之該上邊321 的長度小於該底邊322的長度，使得該兩側邊323與該第 一輻射金屬片31分別夾有一接近90度及一大於90度之傾 斜角，可用於調整該天線之第一及第二操作頻帶之頻率 比，以達成適當之無線區域網路系統頻帶要求。 第4圖為本發明天線之又一實施例之結構圖，包括： 一接地金屬片40，而在其一邊緣403附近，包含一短路點 401與一接地點402 ; —第一輻射金屬片41，位於該接地金 屬片之該邊緣403上方且大致平行於該接地金屬片的邊緣 4〇3 ; —第二輻射金屬片42，位於該接地金屬片的邊緣403 上方，其形狀大致為一梯形，並具有一上邊421、一底邊 422及兩側邊423且包含一饋入點424，其中該上邊421與 1270234 該第一輻射金屬片41之末端相連接，使得該第一輻射金屬 片41與该第二輻射金屬片42形成一共振路徑，用於產生 該天線之第一（較低）及第二（較高）操作頻帶，該饋入 點4M則位於該上邊421與該底邊422之間且靠近於該底 邊422，而該兩侧邊423則分別與該第一輻射金屬片41夾 一傾斜角；一短路金屬臂43,位於該第一輻射金屬片41與 邊接地金屬片40之間，其一端連接至該第二輻射金屬片42 之該底邊422，另一端則連接至該接地金屬片4〇之該短路 點401，用以將該第一輻射金屬片41及該第二輻射金屬片 42電氣連接至接地金屬片4〇並可微調該天線之阻抗匹配； 及一饋入同軸傳輸線44，用以傳輸訊號，包含：一中心導 線441，連接至該第二輻射金屬片42之該饋入點424;及 一外層接地導體442,連接至該接地金屬片4〇之該接地點 402 〇 * 而在本實施例中，該第二輻射金屬片42之該上邊421 的長度大於該底邊422的長度，使得該兩側邊423與該第 一輻射金屬片41分別夾一大於90度及一小於9〇度之傾斜 角，可用於調整該天線之第一及第二操作頻帶之頻率比， 以達成適當之無線區域網路系統頻帶要求。 在本發明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 在不运$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圖為本發明雙頻倒F形天線之一實施例結構圖。 第2圖為本發明天線一實施例之返回損失實驗結果。 第3圖為本發明雙頻倒f形天線.天線之另一實施例結構圖。 1270234 第4圖為本發明雙頻倒F形天線天線之又一實施例結構圖。 【元件符號說明】 1 一雙頻倒F形天線 101，301，401 — 短路點 103,303,403 :邊緣 12,32,42—第二輻射金屬片 122,322,422—底邊 124,324,424 —饋入點 14,34,44一饋入同軸傳輸線 142,342,442—外層接地導體 22—第二（較高）操作頻帶 10,30,40—接地金屬片 102,302,402 —接地點 11，31，41 一第一輻射金屬片 121，321，421— 上邊 123,323,423— 側邊 13,33,43—短路金屬臂 141，341，441一中心導線 21—第一（較低)操作頻帶In recent years, the rapid development of wireless local area networks has led to an increase in the performance requirements of antennas. It requires not only size reduction, but also built-in, integrated and multi-band characteristics. Only has market competitiveness. For electronic communication products for wireless local area networks, there are some conventional inverted-F antenna designs. Most of these designs are single-frequency operation in the 2.4 GHz band or can be operated in dual-frequency but only at 5 σ. - A band that does not fully cover the 2.4A5 GHz full-band 2 band (5 packets 8 with 5.2 and 5.8 GHz bands), and usually requires two current paths in the dual-frequency operation to cause dual-band operation, such as US patents. No. 6,686,886, "Integrated antenna for laptop appncations", which discloses an inverted-F antenna structure in a notebook computer and integrated with the screen ground, the antenna Although there are dual-frequency operation (2.4/5.2 GHz) 'but at 5 GHz only # ^ π ^ ^ 匕 3 GHz level, and its dual 3 is formed by different current paths, increasing the complexity of the circuit design. 』 格 又 又 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞 卞The purpose of the invention is to provide a dual-frequency inverted F-type day-to-the-second path that provides the first- (lower (more) resonant mode current path of the antenna, Not only in the first "resonance mode bandwidth" can cover the wireless local area network 2.4GHz frequency 1270234 and in the second (higher) resonance mode can produce a wide-band operating state, covering the 5 GHz full band 5.2 and 5.8 The GHz band (including the 5.2 and 5.8 GHz bands). The dual-frequency inverted-F antenna structure of the present invention includes a grounded metal piece, a first radiating metal piece, a second radiating metal piece, a shorted metal arm, and a feed-in coaxial transmission line. And a member, wherein the grounding metal piece comprises a short circuit point and a grounding point; the first radiating metal piece is located above an upper end edge of the grounding metal piece and substantially parallel to an edge of the grounding metal piece; the second radiation The metal piece is located above the upper end edge of the grounding metal piece and has a shape substantially a ladder opening and has an upper side, a bottom side and two side edges and includes a feed point, the upper side and the end of the first radiating metal piece Connected Having the first radiating metal sheet and the second radiating metal sheet form a resonant path for producing a first (lower) and second (higher) operating frequency band of the antenna, on the second radiating metal sheet a feeding point is provided, the feeding point is located at the bottom side, and the two sides of the second radiating metal piece are respectively inclined with the first radiation=subject piece for adjusting the first of the antenna And a frequency ratio of the second operating band; the shorting metal arm is located between the first radiating metal piece and the grounding metal piece, one end of which is connected to the bottom edge of the second radiating metal piece, and the other end is connected to the ground a short circuit point of the metal piece; in addition, the feed coaxial transmission line is used for transmitting a signal, the feed coaxial transmission line includes: a core wire and an outer ground conductor, wherein the center wire is connected to the feed of the second radiation metal piece The grounding conductor is connected to the grounding point of the grounding metal piece. In the present invention, the total diameter formed by the first radiating metal piece and the second light-emitting metal piece can provide the antenna First The current path of the low) resonance mode and the second (higher) resonance mode is experimentally proved to be designed such that the total length of the path is about 1/4 wavelength of the center frequency of the first resonance mode, and the second The best signal reception effect is obtained by 1/2 wavelength of the resonant mode center frequency. The present invention has the characteristic of τ: by adjusting the total length of the path 1270234^ to generate dual-band operation, and using the change Short-circuit metal = short-circuit point ί is set to obtain good impedance matching between the two operating bands. At the same time, the length of the upper side and the bottom side of the radiant metal sheet and the inclination angle of the radiant metal sheet on both sides are The two resonant modes can be fine-tuned: the frequency ratio of the heart frequency f reaches the appropriate first- (the phantom operating band and the second (higher) operating band. With the above characteristics, it can be designed for the wireless local area network. 2.4 GHz and dual-band operation of inverted F-type antennas containing 5 GHz full fresh (including the 5 2 and 5.8 GHz bands). Embodiment 1 As shown in FIG. 1 , an embodiment of a dual-frequency inverted-F antenna of the present invention includes a grounded metal piece 10 and a first radiating metal piece. u, a second radiating metal piece 12, a short-circuited metal arm 13 and a member fed into the coaxial transmission line 14, wherein a short-circuit point 101 is provided near the edge 1〇3 of the grounding metal piece 10 for connecting with other members. And a grounding point 102, the short-circuit point 1〇1 is in contact with the short-circuiting metal arm 13, and the grounding point 1〇2 is in contact with the outer layer grounding conductor ι42; the first radiating metal piece 11 is located at the grounding metal piece The edge of the edge 1 〇 3 is substantially parallel to the edge 103; the second radiant metal piece 12 is located above the edge 103 of the grounded metal piece 10, and has a substantially trapezoidal shape, and has an upper edge 121 and a bottom edge 122. The side edges 123 include a feed point 124, wherein the upper side 121 is connected to the end of the first radiating metal sheet 11 such that the first radiating metal sheet 11 and the second radiating metal sheet 12 form a resonance path. The first (lower) used to generate the antenna And a second (higher) operating frequency band, the feeding point 124 is located at the side of the bottom side 122, and the two side edges 123 are respectively inclined with the first radiating metal piece 11; the short-circuiting metal arm 13, Between the first radiating metal piece U and the grounding metal piece 10, one end of which is connected to the bottom edge 122 of the second radiating metal piece 12, and the other end is connected to the short-circuit point 101 of the grounding metal piece 10 for Connecting the first radiating metal piece 11 and the second radiating metal piece 12 to the grounding metal piece 1 〇, and fine-tuning the impedance matching of the first and second operating bands of the antenna; in addition, the feeding is coaxial The transmission line 14 is for transmitting an apostrophe, and the structure comprises a center conductor 141 and an outer ground conductor 142, wherein the center conductor 141 is connected to the feeding point 124 of the second radiant metal sheet 2; the outer ground conductor 142 is connected to the grounding point 102 of the grounding metal piece 1 , thus completing the entire antenna configuration. In this embodiment, the length of the upper side 121 of the second radiating metal piece 12 is greater than the length of the bottom side 122, so that the two side edges 123 and the first radiating metal piece 11 respectively are close to 90 degrees and less than one. A tilt angle of 9 degrees can be used to adjust the frequency ratio of the first and second operating bands of the antenna to achieve an appropriate wireless local area network system band requirement. At the same time, the grounding metal piece 10, the first radiating metal piece u, the second radiating metal piece 12 and the short-circuiting metal arm 13 in the embodiment can be fabricated by single sheet metal stamping or cutting. The first radiation metal sheet 11, the second radiation metal sheet 12, and the short metal arm 13 are formed on a microwave substrate by printing or etching, and then connected to the ground metal sheet 10. 2 is a return loss experiment result of an embodiment of the antenna of the present invention; curve 21 is the first (lower) operating band of the antenna, and curve 22 is the second (higher) operating band of the antenna, The experimental results show that the bandwidth of the first (lower) operating band 21 can be satisfied by the wireless local area network system at 2·4 GHz (2·4-2) under the definition of the 10 dB return loss impedance bandwidth. • Bandwidth requirement of 5 GHz), the bandwidth of the second (higher) operating band 22 can meet the 5 GHz (5.15-5.35, 5.725-5.875 GHz) band requirements of the WLAN system. FIG. 3 is a structural diagram of another embodiment of the antenna of the present invention. In this embodiment, the grounding metal piece 3 is adjacent to one edge 3〇3, and includes a short-circuit point 301 and a grounding point 3〇. 2; the first radiating metal piece 31 is located above the edge 3〇3 of the grounding metal piece and substantially parallel to the edge 303 of the grounding metal 1270234 piece; the second radiating metal piece 32 is located at the edge 303 of the grounding metal piece The upper portion has a substantially trapezoidal shape and has an upper edge 32 and a bottom edge 322 and two side edges 323 and includes a feed point 324. The upper edge 321 is connected to the end of the first light-emitting metal piece 31. The first light-emitting metal piece 31 forms a resonance path with the younger S-shaped metal piece 32 for generating a first (lower) and second (higher) operation band of the antenna, the feeding point 324 is located between the upper edge 321 and the bottom edge 3D and adjacent to the bottom edge 322, and the two sides 323 are respectively inclined with the first light-emitting metal piece 31; a short-circuited metal arm 33 is located Between the first light-emitting metal piece 31 and the grounding metal piece 30, one end of which is connected to the first The bottom edge 322 of the radiating metal piece 32 is connected to the short-circuit point 301 of the grounding metal piece 3 to electrically connect the first radiating metal piece 31 and the second radiating metal piece 32 to the grounding metal. The chip 30 can fine-tune the impedance matching of the antenna; and feed a coaxial transmission line 34 for transmitting signals, including: a center wire 341 connected to the second radiation metal piece; 32 the feeding point 324; The outer ground conductor 342 is connected to the ground point 302 of the ground metal piece 3 . In this embodiment, the length of the upper side 321 of the second radiating metal piece 32 is smaller than the length of the bottom side 322, so that the two side edges 323 and the first radiating metal piece 31 respectively have a closeness of 90 degrees and a A tilt angle greater than 90 degrees can be used to adjust the frequency ratio of the first and second operating bands of the antenna to achieve an appropriate wireless local area network system band requirement. FIG. 4 is a structural diagram of still another embodiment of the antenna of the present invention, comprising: a grounding metal piece 40, and including a short-circuit point 401 and a grounding point 402 near an edge 403 thereof; a first radiating metal piece 41 a second radiant metal piece 42 located above the edge 403 of the grounded metal piece and having a substantially trapezoidal shape. And having an upper side 421, a bottom side 422 and two side edges 423 and including a feeding point 424, wherein the upper side 421 is connected with the end of the first radiating metal piece 41 of the 1270234, so that the first radiating metal piece 41 and The second radiating metal piece 42 forms a resonant path for generating a first (lower) and second (higher) operating frequency band of the antenna, and the feeding point 4M is located at the upper side 421 and the bottom side 422 And being adjacent to the bottom edge 422, wherein the two side edges 423 are respectively inclined with the first radiating metal piece 41; a short-circuiting metal arm 43 is located at the first radiating metal piece 41 and the grounding metal piece 40. One end connected to the second radiation The bottom edge 422 of the strip 42 is connected to the short-circuit point 401 of the grounding metal piece 4 to electrically connect the first radiating metal piece 41 and the second radiating metal piece 42 to the grounding metal piece. 4〇 and fine-tuning the impedance matching of the antenna; and a feeding coaxial transmission line 44 for transmitting signals, comprising: a center conductor 441 connected to the feeding point 424 of the second radiating metal piece 42; and an outer layer The grounding conductor 442 is connected to the grounding point 402 〇* of the grounding metal piece 4, and in the embodiment, the length of the upper side 421 of the second radiating metal piece 42 is greater than the length of the bottom side 422, so that the two The side edge 423 and the first radiating metal piece 41 respectively have an inclination angle greater than 90 degrees and less than 9 degrees, which can be used to adjust the frequency ratio of the first and second operating bands of the antenna to achieve an appropriate wireless area. Network system band requirements. The embodiments described in the description of the invention are merely illustrative of the principles of the invention Therefore, those skilled in the art can modify and change 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 a dual-frequency inverted-F antenna of the present invention. Fig. 2 is a result of the return loss experiment of an embodiment of the antenna of the present invention. Figure 3 is a structural diagram of another embodiment of the dual-frequency inverted f-shaped antenna of the present invention. 1270234 FIG. 4 is a structural diagram of still another embodiment of the dual-frequency inverted-F antenna antenna of the present invention. [Description of component symbols] 1 A dual-frequency inverted-F antenna 101, 301, 401 - Short-circuit point 103, 303, 403: Edge 12, 32, 42 - Second radiating metal piece 122, 322, 422 - Bottom side 124, 324, 424 - Feeding point 14, 34, 44 Feeding coaxial transmission lines 142, 342, 442 - outer ground conductor 22 - second (higher) operating frequency band 10, 30, 40 - grounding metal strips 102, 302, 402 - grounding points 11, 31, 41 a first radiating metal sheet 121, 321, 421 - upper side 123, 323, 423 - Side 13, 33, 43 - Shorted metal arm 141, 341, 441 - Center conductor 21 - First (lower) operating band
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