200849713 九、發明說明： 【發明所屬之技術領域】 本發明是有關於一種通訊與無線電波天線’特別是指 一種槽孔式天線（slot type antenna)。 【先前技術】 在現今多種通訊網路中，它要求於多個基地台之間建 立通訊，而該等基地台中至少一者是行動裝置（mobile)。此 類應用的天線所必須有的重要條件，一般包含有寬廣的波 束涵蓋範圍（beam coverage)(最理想的是具備全向性場型） 、小巧的結構、特定的極化類型，及在特定的頻帶中的足 夠的效能。行動電話、衛星無線電接收器和全球定位系統 (global positioning system，以下簡稱GPS)設備皆是採用上 述的條件的常見典型裝置。事實上，後者通常要求一有相 對地更嚴苛的條件的天線，例如右手圓形極化（right-hand circular polarization)及一非常廣的波束場型（beam coverage pattern)，其涵蓋範圍近乎整個上半球。這些被要求以使一 個GPS接收器能盡可能維持鎖定與追蹤更多可見衛星的訊 號’同時也能提供有效的訊雜比（signal to noise ratio)與前 後比（front to back ratio)(即是輻射場型在一與最大增益之方 向的相反的方向上有較低增益）。 平板天線（patch antenna)即是現今在上述應用中，一種 很普遍的選擇。然而，這必須做出在需求與可行性之間的 權衡取捨’特別在小型裝置或行動裝置的應用中。一般而 吕’平板天線具有有用的低姿態（l〇w profile)，但此點可能 5 200849713 被大接地面的需求所抵銷。一個平板天線因此經常不能在 有限的空間中提供令人滿意的性能。這些平板天線在廣角 的範圍中也不能提供一個好的圓形極化，並且它們在低仰 角容易有較差的增益，造成它們是GPS應用中一個較差的 選擇。這些平板天線也無法提供一個良好的前後比。 另外選擇物是四臂螺旋天線（quadrifilar helical antenna ，以下簡稱QFH)，特別是指印刷形式。QFH天線的幾個優 點是它的相對較小巧的尺寸（與其他那些已知且有用的天線 ，例如正交偶極天線（crossed dipoles))、它的相對較小的直 徑、品質良好的圓形極化（適用於衛星通訊上），及心型方向 場型（cardioid pattern)，例如一主正向波瓣延伸涵蓋一個一 般半球區域並伴隨著良好的前後比。QFH天線的尺寸亦可 藉由介電加載（dielectric loading)或以印刷線性元件成型來 減少。不幸地，QFH天線的要求輻射長度（radiator length) 為期望共振頻率的四分之一波長之整數倍。特別是在手提 或行動裝置上的應用，它們可能需要做出相當大的在微型 化（miniaturization)上的努力來避免讓天線的總長度比期望 還長。為了獲得期望中的性能，饋入系統（feed system)的複 雜性也經常是QFH天線的議題。 另一種習知技藝的天線是槽孔式天線。這些槽孔天線 一般具有一包含至少一個槽孔的平面的結構（有時候會有些 許的翹曲），並且它們在天線空腔諧振器中通常是以微帶傳 輸線（microstrip line)或同軸饋線（coaxial feeder)來供訊號饋 入。雖然槽孔天線的效能是較不需取決於接地面的有無， 6 200849713 但現今已知的槽孔天線都有前述平板天線幾乎所有的缺點 。舉例來說，需製造圓形極化的正交槽孔天線（cr〇ssed “Μ antenna)結構，其較大的尺寸經常不是被期望的。柱面槽孔 天線（cylindrical Sl0t antenna)已經被設計出來設法解決某些 問題，但它未能提供寬廣的波束涵蓋範圍而且也有較長的 傾向。目前尚也未有它們用的簡單饋入系統被提出的報告 公開。 最後，在許多種通訊網路中，天線的費用是一個主要 的考量。適詩GPS的天線，其成本花費可能只是一個飛 航系統中那微不足道的其中一部份，但在曰益普遍的通訊 網路所使用的天線中，花錢無所謂的態度並不實際。例如 :在一般消費者的GPS、行動電話和衛星無線電中，一個 天線需花費0.2美元、2美元或是2〇美元，對一個產品在 市場裡的接受度是有決定性的。 就像大部分置產的物品，一個天線的費用有兩種主要 部分：材料的費用以及裝配這些材料的費用。於此綜觀天 線的，性’有三個主要的作用因素使得天線是有效益的。 首先疋天線的輯，意表提供—天線合格的或更好的性能 ’一些有關於天線設計的考量已在之前討論過，在本篇說 :書中逛會更進一步提及；第二個因素是天線設計的材料 費用’在本篇說明書中此項因素最不被考慮，由於在不同 的天線設計間’材料通常只會改變些許，且這些天線的設 計者在材料費用上是傾向於良好訓練的；第三個因素是天 線設計的材料裝配費用’這些考量是：所使用的機 200849713 於ΐ產技術是否為最便宜的，製作步驟的數量及複雜度是 否為必要去執行的，還有^備的公差（tGleranee)是否需被校 正與、、隹持來達到期望中的產量。最後一項因素是多數的習 知技術都想要的。 【發明内容】 口此本發明之一目的即在提供一種改良的槽孔式通 訊天線。 簡而έ之，本發明之一較佳實施例是一包含一頂部、 一底部及-中心縱軸的天線。該天線還包含有—為導電材 質且以該縱軸為軸心的外殼。該外殼包括一外部的頂壁及 契該外部的頂壁連接並向該天線的底部延伸的外部的側 由-亥外双界定出的内部區域，該内部區域充滿了介 :物貝口亥外设遠包括至少一具有二相對槽孔端的槽孔， 其中’各該槽孔由料相對槽孔端中的位於該側壁之一槽 匕端L伸至另-相對槽孔端，並且各該槽孔的至少一部分 跨越該頂壁。一同軸饋線由該天線的底部延伸至頂部，用 以輸入或輸出電磁能量於該天線的頂壁。 種特別適合行動式及手提 本發明的一項優點是提供一 式應用的天線。 本發明的另一項優點是提供一種可具有小巧結構的天 、本’以及-種能權衡不同尺寸來使其結構最佳化的天線。 用中ΓΓΠΓ優點是提供—種在許多重要與新興的應 中是高效率的天線。 在㈣應用所需的頻帶 200849713 ,本發明之另一優點是提供一種在許多種應用甲能有適 當的訊雜比與前後比的天線。 本發明之另-優點是提供-種能具有寬廣的波束涵蓋 範圍的天線，此波束涵蓋範圍提供接近半球型的輻射範圍 並且接近全向場型（omnidirecti〇nai patteni)。 本發明之另一優點是提供一種採用簡易饋入系統的天 線，可提供應用天線所需要的期望特徵（例如：天線的極化） 〇 本發明之另一優點是提供一種在大角度的範圍中能具 有線性極化（linear p〇larizati〇n)或圓形極化（以⑽以 polarization)的天線（如GPS與衛星無線電應用中一般的需 求：右手圓形極化、波束涵蓋範圍高達16〇度以及具有適 當的前後比）。 本發明之另一優點是提供一種適合於簡單裝配製程中 的天線，也因此有較大的生產量且較低的生產費用。 藉實現本發明的最佳目前已知模式的描述，以及如圖 式中所繪示與下文描述的較佳實施例之工業應用，本發明 之這些與其他的目的和優點對那些熟習該項技藝者將變的 明顯。 【實施方式】 本發明案主張申請於2007年6月7曰的美國專利第 11/759801號申請案為優先權母案，該優先權母案為申請於 2006年12月8曰美國專利第11/6〇8371號申請案的部分延 續案，又，申請於2007年12月7曰的中華民國第 200849713 961獅8號申請案主張前述美國專利第n細37i 案為優先權案’在此可將中華民國第961娜対= 說明書併入作為本發明之參考。 …案的 標號在不同圖式中，相同標號用來表示相同或相似元件或 本赉明之一較佳實施例是一槽孔式 :所、：特別苓閱圖卜本發明的複數個較佳實施例藉由此 /、同參考標號1 〇被緣示。 圖1疋-依據本發明的槽孔天線1G的__透視圖；圖2 是:沿圖i中'線A-A剖切的剖視圖。該槽孔天線1〇包含一 外殼12、一頂部14、一底部16、一内部區域18,及一由 圖中所示該外殼12定義的縱軸2Q。該外殼12包括一頂壁 22、一圓柱型側壁24及一可選擇的底壁％。 該外殼12是由導電材f製成或具有被導電物質覆蓋的 外表面’此導電物f可是銅。該内部區域18被充滿了一種 介電物質，如空氣、塑膠或陶究此類低損耗的類型。此介 電物質亦可為均質（h〇m〇gene(nis)或非均f (inh()m()gen_s) 非均貝忍即於S亥内部區域18中存在多種不同介電常數的 不同種類的物質。舉例來說，此介電物質可以是人工的類 1 亦了以疋"電4數特別高的物質，此物質一般是真介 包物質（real dielectric material)與金屬粒子、包含物或不同 添加物的混合物。 【需要注思的是’在這裡所使用[外]與[内]的措詞是以 元件在本發明槽孔天線10的電特性上的影響為考慮，並不 10 200849713 一疋疋字義上相對於其他未作用元件的物理位置。例如， 該外殼12可能實際上是在—層薄薄的非導體物質（例如泡棉 或塑膠）層之中，扮演著保護罩或整流罩的角色’而並非以 字面之義在整個實施例的最外邊。舉例來說，& 了使生產 更便捷，該外殼12可以被放置在更外層的基底物質上以 提i、物理上的支撐’並且不會馬上大幅地改變該槽孔天線 的性能。上述相關術語的使用在此業界是相#普遍的， 無論如何’藉由前述的說明，目前應該是很明顯易懂的。 在5亥頂壁22且在本實施例中向該外殼12的側壁延 伸有至少-槽孔30。圖i所示的例子具有二類似的槽孔3〇 ’該二槽孔30分別以所選擇的長度呈—十字槽孔的結構， 因此可以與-頻率共振’而此頻率是與該槽孔天線1〇主要 應用的—頻率或多個頻率相同的或接近的。該等槽孔30在 該侧壁24的延伸部分不一定是必要的（例如，該槽孔3〇的 -端在頂壁22上而另一端在側壁24上)，但將兩端設於該 側壁24可能是令人期望的，尤其是為了製作出更小巧的槽 孔天線10的實施例。 早-槽孔30是足以產生線性極化。另_方面本發明槽 減線10的其他實施例能提供其他欲達成的極化。舉例來 ^如果—大體上呈正交的槽孔3G輕射出的電磁場的振幅 疋大致相同且有9G度的相位差，則該槽孔天線iq能提供 圓形極化。 ' 一饋線32是用以與該頂壁22 電連接於一饋入點 33， 11 200849713 發明人觀察到該_ 32在此主要是藉著與該導電頂壁的連 接來起作用，因此強烈作用於該槽孔天線ig内部區域18 之外而不是於内部區域18之内。 立在大部分的實施例中，該饋線32彳簡易地為穿越過該 、P區域18的同轴傳輸線，如圖丨、圖2所示。該饋線32 於此具有-同軸線内導體34、—同軸線外導體以及一同轴 線介電物質38(例如空氣）。該饋線32的位置與其同轴線内 導體34在該饋入點33與該外殼u的連接關係可透過以下 原口來决疋，貫驗、電磁模擬、或僅基於裝配製程上機械 =面的考量，像是縮小介電壁的厚度。—般情況下，但不 疋王邛，该饋線32可簡單地在該内部區域丨8中延伸，並 且該可擁有自己的一縱軸29 ,此縱軸29是與該縱外殼12 的縱軸20互為異心圓的軸（eccentrically⑶狀丨叫，如圖工、 圖2所示。 輻射（radiate)與激發（excite)二措詞可以被用來描述本發 明的槽孔天線10的發射與接收訊號。該槽孔天線1〇的電 特性，像是它的頻率響應與輻射場型，都遵守互反律 (reciprocity rule)。因此，若該槽孔天線1〇是配置調整成輻 射右手圓形極化波，而當該槽孔天線在被激發時，它在 接收模式中可吸收同一頻率的右手圓形極化信號。 一種習知的技術可被擴大應用到本發明槽孔天線1Q， 此技術是以特定值來區別該二槽孔30的長度。在本案例中 ，該饋入點33與該二槽孔30之間的最短距離必須是大致 相等。該等槽孔3 0長度上些微的不同，可使該二槽孔3 〇 12 200849713 與兩不同頻率共振，然後各槽孔30的相位會隨實際頻率呈 現方面而改變。藉由適當地調整該等槽孔3〇的長度，各槽 孔30可獲得一固定的相位偏移（phase 〇ffset)，並且一個在 該等槽孔30之間的預定總相位差可於一期望的特定頻率中 被提供，該特定頻率可如該槽孔天線1〇的主要應用頻率。 為圓形偏極化使用該饋入系統的此種雙頻共振（duai_ resonance)技術，是相對容易且有助於該槽孔天線ι〇的圓形 偏極化實施例在製造上更便宜。此結構亦使特定天線應用 中的天線直徑（水平範圍）與天線側高（垂直範圍）達到更佳的 平衡成為可能。它如此可在非常大的角度區間製造圓形極 化（例如’在垂直面與水平面中往兩側增加大約5〇度）。 如習知技藝所知，生成圓形極化的雙頻共振（d〇uble resonance)方法，一般是生產出相對窄的頻帶。相較下，本 發明槽孔天線10可以是被設計成在一個更寬的頻帶中具有 相當低的電壓駐波比（VSWR)。因此它可以在多個頻率中具 有混合的線性極化，不同於圓形極化的窄頻帶，也因此它 可被用於特別的應用中，像行動裝置的應用，而此類應用 必須有圓形極化與混合的線性極化兩種，儘管這些是在它 們的總頻帶中的不同部分。 許多其他的已知技術可以被使用以更加改良本發明槽 孔天線10。例如，其他形狀可被利用於該等槽孔3〇上。如 此能提供多個益處，增寬的頻帶及減少的尺寸為兩常見益 處。 圖3是一截頭圓錐型槽孔天線1〇的一剖視圖（大體上是 13 200849713 T同於圖1中沿線A_A剖切的剖視圖)，此槽孔天線⑺亦 疋依據本發明。此槽孔天線1G是包含—個圓錐狀的侧壁 凸狀或弓頂狀的頂壁22及一（可選擇的）凹狀的底壁26 圖3因此更在本發明槽孔天線1〇的可能實施例範圍中， 顯示出不同變化。使用任何—種或所有變化樣態可能可以 =成例如· &變該槽孔天線1〇的電特性⑽是擴寬其頻寬 響應特性）、使—實關具美學上的純，或是應付特定應 用中的限制（例如使該底壁26順著—安裝表面成型）。 圖4a-d是於該等槽孔3〇具有不同特徵的該等槽孔天線 的側視圖。圖4a顯示了…亞鈴型的槽孔3〇，圖仆顯示 I錐里槽孔3G，圖4e顯示了曲折型的槽孔3G，圖4d顯 不虫^疋型且斜向延伸的槽孔3〇(要注意的是，此例只是名 義上是螺旋狀的，但這並不是必要條件，—槽孔3()可以有 不樣的曲率或甚至線性且斜向地延伸於該側壁24上）。雖 然圖id的實施例各只有—個槽孔3()，但也應該注意本發 月的k二κ施例可以有任何數量的槽孔，且可以是這些 或其他可能的形狀。 其他習知的技術可被擴大應用到本發明槽孔天線10, 此技術是將有著高介電常數且低損耗的塑膠或陶£，填充 入°亥槽孔天線1G，相較於以空氣來作為介電物質的槽孔天 線10可増進機械上的穩定性和/或減少此槽孔天線10的 體積。 。田2孔天線10的多個實施例是填充有介電物質的，它 們可以疋以傳統的光蝕刻技術製造。這對一個填滿介電物 14 200849713 質的槽孔天線ίο是特別有用的（相對於一介電物質部分填充 的實施例）。例如：首先提供一介電物質的該内部區域18， 然後以金屬化製程來覆蓋其表面，這最後會變成該槽孔天 線10的外殼12。再來，部分金屬化表面以一個預期的圖樣 被移除，以致做出最終的外殼12，特別是包括一個或更多 槽孔30的外殼。 更有其他習知的技術可被擴大應用到本發明槽孔天線 10，此技術是提供一個阻流器（choke)在該槽孔天線10的背 面。一個普通的介電物質填充的四分之一波長同軸套管式 的阻流器（dielectric loaded quarter wavelength coaxial sleeve type choke)或一個短路的徑向傳輸式的阻流器（short circuited radial transmission form of choke)可以供該槽孑L 天 線10從一物理上的結合的平台分離，因此減少了不希望的 耦合效果，也降低對環境的敏感度，例如，由於手握著行 動式手持裝置而對此裝置的影響。選擇一個適合的阻流器 類型，它的尺寸及位置即能為一槽孔天線10的特定的實施 例設計。或者，特別是需要一個小巧並結合在一起的天線 與阻流器時，此槽孔天線10可以被設計成包含此阻流器的 功效，或是在更極端的例子中，兩者皆被設計成結合在一 起並且被最佳化。 現在再次回到圖1，此圖描述了本發明槽孔天線10的 一實施例，而此實施例對一些設計考量的討論有幫助。利 用與圖1所示相似的結構，設計一個線性極化或一般混合 線性極化的槽孔天線10是可能的。第一步驟是採用兩個有 15 200849713 耆相同長度的槽孔30，且各槽孔30與該饋線32的最短距 離大致相等；其次步驟是基於期望的頻率與所使用的介電 物貝，選擇出一些初始的尺寸，這些尺寸可包括該外殼12 的一半徑或多個半徑，以及該頂壁22、側壁24、底壁26( 如果有的話）的厚度。設計者可決定（經過實驗或模擬）其他 的《數以在加或不加匹配網路（matching network)的期望 ^員贡中，獲彳于一個合理的反射損耗（return l〇ss)。也就是說 ，在一些案例中，特別是當高介電常數的介電物質充入該 内。卩區域18時，不使用匹配網路來達成在期望頻帶中的阻 抗匹配是不可能的。這些參數包括了該等槽孔3〇的長度（於 此例中最好是等長）、該側壁24的高度（例如該槽孔天線1〇 本身的高度），及以該外殼12的縱軸20為軸的該側壁24的 咎向距離。由於該二槽孔30會以相同相位輻射，該槽孔天 線10也因此被設計成單純的線性極化。 為了要設計一圓形極化的槽孔天線1〇，兩個長度僅有 些微差距的槽孔30可以被使用與決定，以代替兩個長度一 樣的槽孔30。該二槽孔30因此最好可有相似的形狀，但並 不一定如此。有些微差別的該等形狀是很有用的，例如， 可在該等槽孔30之一的兩端加上複數切口，以允許微調該 圓形極化，使其相對降低裝配製程產生的公差的敏感度。 應該要注意的是，無論如何，僅藉由改變該二槽孔3〇的長 度來將線性極化的設計改變成圓形極化的設計，並非總是 可能的，例如當使用一種有著非常高的介電常數的介電物 質時。如果該二槽孔30並非正交，擁有一個線性極化的槽 16 200849713 孔天線ίο依然是有可能的，但因此使為了獲得圓形極化而 改變設計這件事變得更加困難。 發明人也已觀察到，選擇一些零件的參數而因此使該 天線的杈型由平常的方向被傾斜，如此是可能的，特別是 在圓形極化的的實施例中，並且當該槽孔天線1〇與該阻流 器連接時。這些參數的其中之一是該槽孔天線1〇中該等槽 孔與底部的最短距離。從而獲得的傾斜角一般可以為5至 10度。如此是在應用上有潛在的用處，此用處在於希望將 該天線的輻射場型的主要的方向轉向一特定的方向，比如 說離開使用者頭部或身體的方向。 當然，仍有其他習知的技術可被應用至更加擴大本發 明槽孔天線1 〇的性能。 圖5是一交替的圓柱狀槽孔天線1〇的一剖視圖（大體上 疋等同於圖1中/口、線A-A所剖切的剖視圖），此槽孔天線i 〇 也是根據本發明而來。就像觀察到的，在這裡的該同軸線 外導體36實際上是延伸至該頂壁22的_塊區域，該外殼 12的此區域是不具導電材質。無論如何，言亥同軸線内導體 34延伸出，亥槽孔天線1〇，並且呈u型地與該外殼η的頂 壁22上為導電材質的饋入點33連接。 圖5也緣示與圖！至2所示的實施例不同的其他可能 的區別。就像圖中顯示底壁被刪除，該底壁可以是可選擇 的’而且該同軸線外導體36是與該外殼12電性分離。在 此實施例中，該等槽孔3G可能f要在更長_些，但藉由使 用特定的形狀，像是螺旋結構，該等槽孔 3 〇的總延伸或垂 17 200849713 直延伸可以被減少。 另外一種變化是將饋線32通過一内殼40以形成一導 管42，以供該饋線32的同軸零件使用。除此之外，該饋線 32 —般能具有與該外殼12的縱軸20互為異心圓的一縱軸 29，但並非全然如此。 在電性方面，該内殼40是可導電的且最好是與該同軸 線外導體36連接。該内殼40執行以類似於同一發明人發 明的另一專利案（前述中華民國第96146808號申請案）中的 槽孔天線内侧壁。比較圖6(先前技術）可以看見，無論如何 ，本實施例的内殼40在結構上是大大地不同於先前槽孔天 線的内側壁，如此使得本槽孔天、線1〇纟有裝配製程上機械 方面的優點（以下再討論）。 t明人已觀察到，本發明槽孔天線1〇可以經由許多為 人所知的製作方法來加以製造。尤其是，此製作並未有特 別限定而能夠是簡單的並且達成產品高產量與高品質，以 2經濟的。例如，該等槽孔3G可以是―開始就形成為該 $ 12的H像是用鑄造，或U們也可在之後用切 ;或钱刻來成型。相似地，如果有提供，該内殼40可以一 :始就與該外殼12成型；—介電物質放置的地方作為 始點，將該外殼12之後再加上去 ，，，、 内邱p A 將中間的那部分定義為 内口化域18,反之亦然；或是該内殼4〇可以 例如用焊接。在許多實施例中 女衣’ 部區域18中的介電物質，在其他的Z間早地成為在該内 於該内部區域18的介電物質是 中’-可被採用 允彳為凝固的物質。並且 18 200849713 對於任何！4類存在於既有開口的物質，當它仍是液態時， 匕可以疋被消除的，或者於它硬化時被切除。於其他的實 %例中 固恶物質的内部區域18可以當作將導體外殼12 k附上去的基底，例如用鑄造（^出邱）、喷塗與濺 鍍（sputtering)等等。然後該等槽孔3〇可以以它們的最後形 狀來被切割或钱刻於其上。 假若期望，該槽孔天線1〇的阻抗可以是與其連接的裝 置互相匹配。也就是說，該槽孔天線1〇的原始阻抗被轉換 成或接近此裝置提供的一要求負載阻抗，一般是5〇歐姆。 為達成這目的，許多為人所知的習知技術可以被使用 。例如，一個四分之一波長的轉換器可以被使用，其可為 一個四分之一波長的傳輸線，在此實施例為具有一預定的 特性阻抗並被放置於饋入點33與該裝置之間的同軸饋線32 。另一個有用的習知技術是電抗匹配（reactive matching)， 係利用諸如電容或電感的一電抗元件，此電抗元件係以謹 慎的接地的形式或是一個開路截線（〇pen stub)的形式來被設 置成與一根傳輸線串聯或並聯，此傳輸線直接與該饋線 相接。一種更小巧且具有更好的性能的方式，是使用一匹 配網路，其最好是但並絕對要放置於饋入點33上。或者， 此匹配網路甚至可以被放置在槽孔天線1〇的底部16。舉例 來說，該匹配網路可以被放置在外殼12内，或甚至在槽孔 天線10的外，或者即使此阻流器存在時，該匹配網路可以 被設置在阻流器之後。此匹配網路可以被完整地或部分地 具體實現在一般的多層印刷電路板。如果使用該匹配板， 19 200849713 它就能被放置於該槽孔天線1G的外側，最好是由該饋線32 橫向延伸，並且匹配板的元件與同軸線内導體34及同軸線 外導體36連接並與該外殼12連接於該頂壁22。 圖7是一是用於本發明的匹配網路5〇的等效電路的一 簡圖（在此的電路有時是被稱為L型匹配網路）。此特性阻抗 是藉由-與該同軸線内導體34串聯的一電感52及設置於 同軸線内導體34與同軸線外導體36之間的_並聯電容μ 來實現。該電感52與電容54中的-者或皆是分離的零件 ，抑或是以在一電路板上導電路徑或軌跡來實現。 惟以上所述實施例，應該了解到它們僅“以” 之幾個實施方式而已，本發明之範圍不應受限於上述示# 的實施例，而應以以下的專利申請範圍及其均等來界定=乾 20 200849713 【圖式簡單說明】 圖1是依據本發明槽孔天線的一透視圖； 圖2是一中沿圖1中線a-a剖切的剖視圖； 圖3是一截頭圓錐型槽孔天線的一剖視圖（大體上是等 同於圖1中沿線A-A剖切的剖視圖）； 圖4a至d是於該等槽孔具有不同特徵的該等槽孔天線 1〇的側視圖； 圖5疋一父替的圓柱狀槽孔天線的一剖視圖（大體上是 等同於圖1中沿線A-A所剖切的剖視圖），此槽孔天線也是 根據本發明而來； 圖6(背景技術）是依據本應用技術之一槽孔天線的一剖 視圖，用以在此顯示圖5中的該内殼與該内側壁具有結構 上的不同；及 圖7是一是用於本發明的匹配網路的等效電路的一簡 圖（該電路於此有時是被稱為L型匹配網路）。 21 200849713 【主要元件符號說明】 10····· …··槽孔天線 32.···. .....饋線 12••… …··外殼 33 ••… .....饋入點 14 …··頂部 34··.·. …··同軸線内導體 16••… •…·底部 36•… ••…同軸線外導體 18••… ……内部區域 38····. ••…介電物質 20 …··縱軸 40····. …··内殼 22•…· …··頂壁 ' 42 …··導管 24…… …··側壁 50……· ••…匹配電路 26…… •…底壁 52••… 電感 29•…· •…縱軸 54••… ••…電容 30····. •…槽孔 22200849713 IX. Description of the Invention: [Technical Field] The present invention relates to a communication and radio wave antenna', particularly to a slot type antenna. [Prior Art] In today's various communication networks, it requires communication between a plurality of base stations, and at least one of the base stations is a mobile. The important conditions necessary for the antennas of such applications generally include broad beam coverage (ideally omnidirectional fields), small structures, specific polarization types, and specific Sufficient performance in the frequency band. Mobile phones, satellite radio receivers, and global positioning systems (GPS) devices are common typical devices that use the above conditions. In fact, the latter usually requires an antenna with relatively more stringent conditions, such as right-hand circular polarization and a very broad beam coverage pattern, which covers almost the entire range. The upper hemisphere. These are required to enable a GPS receiver to maintain as much as possible to lock and track more visible satellite signals' while also providing an effective signal to noise ratio and front to back ratio (ie, The radiation pattern has a lower gain in the opposite direction to the direction of maximum gain). Patch antennas are a common choice in today's applications. However, this must make a trade-off between demand and feasibility', especially in small devices or mobile devices. In general, the Lv's flat panel antenna has a useful low profile (l〇w profile), but this may be offset by the need for a large ground plane. A flat panel antenna therefore often does not provide satisfactory performance in a limited space. These patch antennas also do not provide a good circular polarization over a wide angle range, and they tend to have poor gain at low elevation angles, making them a poor choice for GPS applications. These panel antennas also do not provide a good front-to-back ratio. Further, the selection is a quadrifilar helical antenna (hereinafter referred to as QFH), and particularly refers to a printed form. Several advantages of the QFH antenna are its relatively small size (compared to other known and useful antennas, such as crossed dipoles), its relatively small diameter, and good quality roundness. Polarization (for satellite communications), and cardioid pattern, such as a main positive lobe extension covering a general hemisphere region with a good front-to-back ratio. The size of the QFH antenna can also be reduced by dielectric loading or by molding a linear component. Unfortunately, the required radiation length of a QFH antenna is an integer multiple of a quarter wavelength of the desired resonant frequency. Especially in portable or mobile devices, they may need to make considerable miniaturization efforts to avoid making the total length of the antenna longer than desired. In order to achieve the desired performance, the complexity of the feed system is often the subject of QFH antennas. Another conventional antenna is a slotted antenna. These slot antennas typically have a planar structure (sometimes slightly warped) containing at least one slot, and they are typically microstrip lines or coaxial feeds in the antenna cavity resonator ( Coaxial feeder) for signal feed. Although the performance of the slot antenna is less dependent on the presence or absence of the ground plane, 6 200849713, however, slot antennas known today have almost all of the disadvantages of the aforementioned patch antennas. For example, it is necessary to fabricate a circularly polarized orthogonal slot antenna (cr〇ssed "Μ antenna" structure, whose larger size is often not desired. Cylindrical slot antennas have been designed I came out to solve some problems, but it failed to provide a broad beam coverage and a long-term tendency. There is no report on the simple feed system that they have been published. Finally, in many kinds of communication networks, The cost of the antenna is a major consideration. The cost of the GPS antenna can be just a negligible part of a flight system, but it doesn’t matter if you spend money on an antenna used in a popular communication network. The attitude is not practical. For example, in the general consumer's GPS, mobile phone and satellite radio, an antenna costs 0.2 US dollars, 2 US dollars or 2 US dollars, which is decisive for the acceptance of a product in the market. Like most home-made items, the cost of an antenna has two main parts: the cost of the material and the cost of assembling the material. Looking at the antenna, the sex 'has three main contributing factors to make the antenna beneficial. First of all, the 疋 antenna series, the Italian version provides - the antenna is qualified or better performance'. Some considerations about antenna design have been discussed before. In this article: the book is further mentioned in the book; the second factor is the material cost of the antenna design. This factor is the least considered in this specification, because the material is usually only used in different antenna designs. A little change, and the designers of these antennas tend to be well trained in material costs; the third factor is the material assembly cost of the antenna design. 'The considerations are: whether the machine used in 200849713 is the cheapest in the production technology. Whether the number and complexity of the production steps are necessary, and whether the tolerance (tGleranee) needs to be corrected and maintained to achieve the desired output. The last factor is the majority of the prior art. SUMMARY OF THE INVENTION One object of the present invention is to provide an improved slotted communication antenna. Briefly, one of the present inventions The preferred embodiment is an antenna comprising a top portion, a bottom portion and a center longitudinal axis. The antenna further includes an outer casing that is electrically conductive and has an axis centered on the longitudinal axis. The outer casing includes an outer top wall and a The outer top wall of the outer top wall and the outer side extending toward the bottom of the antenna is defined by an inner region defined by the outer double, and the inner region is filled with the medium: the outer shell comprises at least one opposite slot. a slot of the end, wherein each of the slots extends from the slot end L of the slot opposite the slot end to the other slot opposite the slot end, and at least a portion of each slot spans the top wall. The coaxial feed line extends from the bottom to the top of the antenna for inputting or outputting electromagnetic energy to the top wall of the antenna. One advantage that is particularly suitable for mobile and portable embodiments of the present invention is to provide an antenna for one application. Another advantage of the present invention is to provide an antenna that can have a compact structure, and that can be weighed to different sizes to optimize its structure. The advantage of using the medium is to provide an antenna that is highly efficient in many important and emerging applications. Another advantage of the present invention is that it provides an antenna having a suitable signal-to-noise ratio and front-to-back ratio in many applications. Another advantage of the present invention is to provide an antenna that can have a wide beam coverage range that provides near-hemispherical radiation range and close to omnidirecti 〇nai patteni. Another advantage of the present invention is to provide an antenna employing a simple feed system that provides the desired features required to apply the antenna (e.g., polarization of the antenna). Another advantage of the present invention is that it provides a wide range of angles. An antenna capable of linear polarization (linear p〇larizati〇n) or circular polarization (with (10) polarization) (eg general requirements in GPS and satellite radio applications: right-hand circular polarization, beam coverage up to 16〇) Degree as well as having an appropriate front-to-back ratio). Another advantage of the present invention is to provide an antenna suitable for use in a simple assembly process, and thus has a large throughput and a low production cost. These and other objects and advantages of the present invention are familiar to those skilled in the art by the description of the best presently known modes of the invention and the industrial application of the preferred embodiments described below. The person will become more obvious. [Embodiment] The present application claims the priority of the US Patent No. 11/759,801 filed on Jun. 7, 2007, the priority of which is filed on December 8, 2006, US Patent No. 11 Partial continuation of the application of /6〇8371, and the application for the Republic of China No. 200849713 961 Lion No. 8 on December 7th, 2007, claims that the aforementioned US patent n-th 37i case is a priority case. The specification of the Republic of China No. 961 対 = is incorporated herein by reference. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION The same reference numerals are used to designate the same or similar elements or a preferred embodiment of the present invention is a slotted type: By way of this, the same reference numeral 1 〇 is shown. Figure 1A is a perspective view of a slot antenna 1G according to the present invention; Figure 2 is a cross-sectional view taken along line A-A of Figure i. The slot antenna 1A includes a housing 12, a top portion 14, a bottom portion 16, an interior region 18, and a longitudinal axis 2Q defined by the housing 12 as shown. The outer casing 12 includes a top wall 22, a cylindrical side wall 24 and an optional bottom wall %. The outer casing 12 is made of a conductive material f or has an outer surface covered by a conductive material. This conductive material f may be copper. The inner region 18 is filled with a type of dielectric material such as air, plastic or ceramic. The dielectric substance may also be homogeneous (h〇m〇gene(nis) or non-uniform f(inh()m()gen_s)). The heterogeneity of the dielectric material is different in the internal region 18 of the Shai. a substance of the kind. For example, the dielectric substance may be an artificial class 1 or a substance having a particularly high number of electricity, which is generally a real dielectric material and metal particles, inclusions. Or a mixture of different additives. [It is to be noted that the words [external] and [inside] used herein are based on the influence of the elements on the electrical characteristics of the slot antenna 10 of the present invention, and are not considered to be 10 200849713 A physical location relative to other unacting elements. For example, the outer casing 12 may actually be in a thin layer of non-conducting material (such as foam or plastic), acting as a protective cover or rectifying. The role of the hood 'is not literally at the outermost point of the entire embodiment. For example, & to make production more convenient, the outer casing 12 can be placed on the outer layer of the substrate material to provide i, physical Support' and will not change dramatically The performance of the slot antenna is changed. The use of the above related terms is common in the industry, however, by the foregoing description, it should be clearly understandable at present. In the 5th ceiling wall 22 and in this implementation In the example, at least a slot 30 extends into a side wall of the outer casing 12. The example shown in Fig. i has two similar slots 3'', and the two slots 30 have a cross-hole structure of a selected length, respectively. It is therefore possible to resonate with the -frequency which is the same or close to the frequency or frequencies at which the slot antenna 1 is primarily applied. The slots 30 are not necessarily necessary at the extension of the side wall 24. (for example, the slot 3 end is on the top wall 22 and the other end is on the side wall 24), but it may be desirable to have both ends on the side wall 24, especially in order to make it smaller. An embodiment of the slot antenna 10. The early-slot 30 is sufficient to produce linear polarization. Other embodiments of the slot reducer 10 of the present invention provide other polarizations to be achieved. The amplitudes of the electromagnetic fields emitted by the orthogonal slots 3G are substantially the same and The phase difference of 9G degrees, the slot antenna iq can provide circular polarization. 'A feeder 32 is used to electrically connect the top wall 22 to a feed point 33, 11 200849713 The inventors observed that the _ 32 This is primarily due to the connection to the electrically conductive top wall and therefore acts strongly outside of the slot antenna ig inner region 18 rather than within the inner region 18. In most embodiments, the feeder 32彳 is simply a coaxial transmission line that passes through the P area 18, as shown in FIG. 2 and FIG. 2. The feed line 32 has a coaxial inner conductor 34, a coaxial outer conductor, and a coaxial line. Electrical substance 38 (eg air). The position of the feed line 32 and the connection relationship between the feed line 33 and the outer casing u at the feed point 33 can be determined through the following original ports, through inspection, electromagnetic simulation, or only on the mechanical process of the assembly process. , like reducing the thickness of the dielectric wall. In general, but not the king, the feeder 32 can simply extend in the inner region 丨8 and can have its own longitudinal axis 29, which is the longitudinal axis of the longitudinal housing 12. 20 mutually eccentrically (3)-like squeaking, as shown in Fig. 2. The words "radiate" and "excite" can be used to describe the transmission and reception of the slot antenna 10 of the present invention. The electrical characteristics of the slot antenna, such as its frequency response and radiation pattern, are subject to the reciprocity rule. Therefore, if the slot antenna is configured to be radiated to the right hand circle Polarized wave, and when the slot antenna is excited, it can absorb the right-hand circularly polarized signal of the same frequency in the receiving mode. A conventional technique can be extended to the slot antenna 1Q of the present invention, The technique distinguishes the length of the two slots 30 by a specific value. In this case, the shortest distance between the feed point 33 and the two slots 30 must be substantially equal. The slots 30 have a slight length. The difference between the two slots 3 〇12 200849713 and the two The frequency resonates, and then the phase of each slot 30 changes with respect to the actual frequency presentation. By appropriately adjusting the length of the slots 3, each slot 30 can obtain a fixed phase offset (phase 〇 ffset). And a predetermined total phase difference between the slots 30 can be provided at a desired particular frequency, such as the primary application frequency of the slot antenna 1 。. For circular polarization This dual frequency resonance (duai_ resonance) technique of the feed system is relatively inexpensive and is less expensive to manufacture in a circular polarization embodiment that facilitates the slot antenna. This configuration also enables specific antenna applications. It is possible to achieve a better balance between the antenna diameter (horizontal range) and the antenna side height (vertical range). It is possible to create circular polarizations in very large angular intervals (eg 'on both sides in the vertical and horizontal planes An increase of about 5 degrees.) As is known in the art, a dual-frequency resonance method for generating circular polarization generally produces a relatively narrow frequency band. In contrast, the slot antenna 10 of the present invention is compared. Can be Designed to have a relatively low voltage standing wave ratio (VSWR) in a wider frequency band. Therefore it can have mixed linear polarization in multiple frequencies, unlike a narrow band of circular polarization, and therefore it Can be used in special applications, like the application of mobile devices, and such applications must have both circular polarization and mixed linear polarization, although these are different parts of their total frequency band. Many others Known techniques can be used to further improve the slot antenna 10 of the present invention. For example, other shapes can be utilized on the slots 3. This provides multiple benefits, widening the frequency band and reducing the size of the two common Figure 3 is a cross-sectional view of a frustoconical slot antenna 1 (generally a cross-sectional view of 13 200849713 T taken along line A_A of Figure 1), which slot antenna (7) is also in accordance with the present invention. The slot antenna 1G is a top wall 22 including a conical side wall convex or bow-shaped shape and an (optional) concave bottom wall 26. FIG. 3 is thus further provided in the slot antenna of the present invention. In the range of possible embodiments, different variations are shown. Using any or all of the variations may be, for example, changing the electrical characteristics of the slot antenna (10) to broaden its bandwidth response characteristics, making it practically pure, or Coping with limitations in specific applications (eg, having the bottom wall 26 follow the mounting surface). Figures 4a-d are side views of the slot antennas having different features in the slots 3''. Figure 4a shows the slot of the ... bell type, the servant shows the slot 3G in the I cone, and Figure 4e shows the slot 3G of the meandering type. Figure 4d shows the slot of the obliquely extending slot. 3〇 (It should be noted that this example is only nominally spiral, but this is not a requirement - slot 3 () may have a different curvature or even linear and obliquely extend on the side wall 24 ). Although the embodiment of Figure id has only one slot 3(), it should also be noted that the k2K embodiment of this month may have any number of slots and may be of these or other possible shapes. Other conventional techniques can be extended to the slot antenna 10 of the present invention. This technique is to fill a 1G slotted antenna with a high dielectric constant and low loss plastic or ceramic, compared to air. The slot antenna 10 as a dielectric substance can mechanically stabilize and/or reduce the volume of the slot antenna 10. . Various embodiments of the field 2-hole antenna 10 are filled with a dielectric material which can be fabricated by conventional photolithographic techniques. This is particularly useful for a slotted antenna ίο filled with dielectric 14 200849713 (an embodiment of partial filling with respect to a dielectric material). For example, the inner region 18 of a dielectric material is first provided and then covered by a metallization process which eventually becomes the outer casing 12 of the slot antenna 10. Again, the partially metallized surface is removed in a desired pattern so that the final outer casing 12, particularly the outer casing including one or more slots 30, is made. More conventional techniques can be extended to the slot antenna 10 of the present invention, which provides a choke on the back of the slot antenna 10. A dielectric-filled quarter-wave coaxial sleeve type choke or a short-circuited radial transmission form of a short circuited radial transmission form of a short circuited radial transmission form of The choke can be used to separate the antenna 10 from a physically bonded platform, thereby reducing undesirable coupling effects and reducing environmental sensitivity, for example, due to the hand held mobile device. The impact of the device. A suitable choke type is chosen which is sized and positioned to be a specific embodiment of a slot antenna 10. Alternatively, the slot antenna 10 can be designed to include the effectiveness of the baffle, especially in the more extreme case, when both a compact and combined antenna and choke are required. Together they are combined and optimized. Returning now to Figure 1, this figure depicts an embodiment of the slot antenna 10 of the present invention, and this embodiment is useful for some discussion of design considerations. It is possible to design a slotted antenna 10 of linear polarization or generally mixed linear polarization using a structure similar to that shown in FIG. The first step is to use two slots 30 having the same length of 15 200849713 ,, and the shortest distance between each slot 30 and the feeder 32 is substantially equal; the second step is based on the desired frequency and the dielectric material used, Some initial dimensions may be included, including a radius or radii of the outer casing 12, and the thickness of the top wall 22, side walls 24, bottom wall 26, if any. The designer can decide (through experimentation or simulation) that other numbers are expected to be in a reasonable return loss (return l〇ss) in the expectation of adding or not matching networks. That is to say, in some cases, especially when a high dielectric constant dielectric substance is charged therein. In the case of zone 18, it is not possible to use a matching network to achieve impedance matching in the desired frequency band. These parameters include the length of the slots 3〇 (preferably equal in this example), the height of the side wall 24 (e.g., the height of the slot antenna 1 itself), and the longitudinal axis of the housing 12 20 is the slanting distance of the side wall 24 of the shaft. Since the two slots 30 will radiate in the same phase, the slot antenna 10 is thus designed to be simply linearly polarized. In order to design a circularly polarized slot antenna 1 两个, two slots 30 having only a slight difference in length can be used and determined instead of the slots 30 of the same length. The two slots 30 are therefore preferably similar in shape, but this need not be the case. Some of these slightly different shapes are useful, for example, a plurality of slits may be added to one end of one of the slots 30 to allow for fine tuning of the circular polarization to relatively reduce the tolerances produced by the assembly process. Sensitivity. It should be noted that, in any case, it is not always possible to change the linearly polarized design to a circularly polarized design by merely changing the length of the two slots 3〇, for example when using a very high The dielectric constant of the dielectric material. If the two slots 30 are not orthogonal, having a linearly polarized slot 16 200849713 Hole antenna ίο is still possible, but it is therefore more difficult to change the design in order to obtain circular polarization. The inventors have also observed that it is possible to select the parameters of some parts and thus tilt the antenna of the antenna from the usual direction, especially in circularly polarized embodiments, and when the slot When the antenna 1 is connected to the choke. One of these parameters is the shortest distance between the slots and the bottom of the slot antenna 1〇. The tilt angle thus obtained can generally be 5 to 10 degrees. This is potentially useful in applications where it is desirable to divert the primary direction of the antenna's radiation pattern to a particular direction, such as the direction of the user's head or body. Of course, there are still other conventional techniques that can be applied to further expand the performance of the slot antenna of the present invention. Figure 5 is a cross-sectional view of an alternate cylindrical slot antenna 1 (generally equivalent to the cross-sectional view taken in Figure 1 / port, line A-A), which slot antenna i 也是 is also in accordance with the present invention. As observed, the coaxial outer conductor 36 herein extends substantially to the _block region of the top wall 22, which is not electrically conductive. In any case, the inner coaxial inner conductor 34 extends out of the slot antenna and is connected in a u-shaped manner to the feed point 33 of the top wall 22 of the outer casing n which is electrically conductive. Figure 5 also shows the picture! There are other possible differences that differ from the embodiment shown in Figure 2. As shown in the figure, the bottom wall is removed, the bottom wall may be selectable and the coaxial outer conductor 36 is electrically separated from the outer casing 12. In this embodiment, the slots 3G may be longer, but by using a specific shape, such as a spiral structure, the total extension of the slots 3 或 or the vertical extension of the 2008 17 200849713 can be cut back. Another variation is to pass the feed line 32 through an inner casing 40 to form a conduit 42 for use with the coaxial components of the feed line 32. In addition, the feed line 32 can generally have a longitudinal axis 29 that is concentric with the longitudinal axis 20 of the outer casing 12, but this is not entirely the case. Electrically, the inner casing 40 is electrically conductive and is preferably coupled to the coaxial outer conductor 36. The inner casing 40 performs the inner side wall of the slot antenna in another patent (the aforementioned application of the Republic of China No. 96146808), which is similar to the same inventor's invention. Comparing Fig. 6 (prior art), it can be seen that, in any case, the inner casing 40 of the present embodiment is structurally different from the inner side wall of the previous slot antenna, so that the slot hole and the line 1 have an assembly process. Mechanical advantages (discussed below). It has been observed that the slot antenna 1 of the present invention can be manufactured by a number of well-known fabrication methods. In particular, this production is not particularly limited and can be simple and achieve high yield and high quality of the product, which is economical. For example, the slots 3G may be "starting to form the H 12 image for casting, or the Us may be cut later; or by engraving." Similarly, if provided, the inner casing 40 can be formed with the outer casing 12; the place where the dielectric substance is placed is used as the starting point, and the outer casing 12 is added later, and, The middle portion is defined as the inner opening domain 18 and vice versa; or the inner casing 4 can be welded, for example. In many embodiments, the dielectric material in the 'coating region 18 of the vestibule is pre-existing between the other Z-intermediates in the internal region 18--can be used as a solidifying substance . And 18 200849713 For any! Class 4 is a substance that exists in an existing opening. When it is still in a liquid state, it can be removed or it can be removed when it hardens. In other embodiments, the inner region 18 of the solidaceous substance can be used as a substrate to which the conductor casing 12k is attached, for example, by casting, spraying and sputtering, and the like. The slots 3〇 can then be cut or money engraved on them in their final shape. If desired, the impedance of the slot antenna 1 可以 can be matched to the device to which it is connected. That is, the original impedance of the slot antenna 1〇 is converted to or near a required load impedance provided by the device, typically 5 ohms. To achieve this, many well-known techniques can be used. For example, a quarter-wavelength converter can be used, which can be a quarter-wavelength transmission line, in this embodiment having a predetermined characteristic impedance and placed at the feed point 33 and the device. Coaxial feed line 32. Another useful prior art technique is reactive matching, which utilizes a reactive component such as a capacitor or inductor that is in the form of a cautious ground or an open stub. It is arranged in series or in parallel with a transmission line, which is directly connected to the feeder. One way to be smaller and have better performance is to use a matching network that is preferably but absolutely placed on the feed point 33. Alternatively, the matching network can even be placed at the bottom 16 of the slot antenna 1〇. For example, the matching network can be placed within the housing 12, or even outside of the slot antenna 10, or even if the choke is present, the matching network can be placed after the choke. This matching network can be implemented in whole or in part on a typical multilayer printed circuit board. If the matching board is used, 19 200849713 it can be placed outside the slot antenna 1G, preferably extending laterally from the feed line 32, and the components of the matching board are connected to the coaxial inner conductor 34 and the coaxial outer conductor 36. And the outer casing 12 is connected to the top wall 22. Figure 7 is a simplified diagram of an equivalent circuit for the matching network 5 of the present invention (the circuit herein is sometimes referred to as an L-type matching network). This characteristic impedance is achieved by an inductance 52 in series with the coaxial inner conductor 34 and a _ shunt capacitance μ disposed between the coaxial inner conductor 34 and the coaxial outer conductor 36. The inductor 52 and the capacitor 54 are either separate components or are implemented in a conductive path or track on a circuit board. However, the above-mentioned embodiments are to be understood that they are only "in" several embodiments, and the scope of the present invention should not be limited to the above-described embodiment of the invention, but should be based on the scope of the following patent application and its equivalent. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a slot antenna according to the present invention; FIG. 2 is a cross-sectional view taken along line aa of FIG. 1; FIG. 3 is a truncated conical groove. A cross-sectional view of the aperture antenna (generally equivalent to the cross-sectional view taken along line AA in Fig. 1); Figures 4a to d are side views of the slot antennas 1 具有 having different features in the slots; Figure 5 A cross-sectional view of a parent-shaped cylindrical slot antenna (generally equivalent to the cross-sectional view taken along line AA in FIG. 1), the slot antenna is also in accordance with the present invention; FIG. 6 (background art) is based on A cross-sectional view of a slot antenna of one of the application techniques for showing that the inner casing of FIG. 5 is structurally different from the inner side wall; and FIG. 7 is an equivalent of a matching network for use in the present invention. a simplified diagram of a circuit (this circuit is sometimes referred to as L-type matching network). 21 200849713 [Explanation of main component symbols] 10········Slot antenna 32.···...... Feeder 12••...···Shell 33 ••... Inlet point 14...··Top 34····....··Coaxial inner conductor 16••... •...·Bottom 36•... ••...Coaxial outer conductor 18••... ......Internal area 38··· ·••...Dielectric material 20 ...··Vertical axis 40································································· · ••...matching circuit 26... •...bottom wall 52••...inductor 29•...· •...vertical axis 54••... ••...capacitor 30····.....slot 22