Ί270676 九、發明說明： 【發明所屬之技術領域】 本發明係關於一種電磁訊號量測系統’尤指一種以低干 擾電磁場感測技術為基礎，配合自動定位機構之電磁訊號 量測系統，特別適用於開放空間之現場（〇n_site)天線場型量 測，例如RFID讀寫器（Reader)及RFID標籤（Tag)之天線場型 量測。本發明又關於一種使用於上述量測系統之電磁訊號 量測方法。 【先前技術】 無線射頻識別（Radio Frequency Identification，RFID)的 發展是全球所關注的，已被看好能大量的取代條碼 (barcode)，未來的市場需求量將是相當驚人。RFID系統主 要包含RFID讀寫器及RFID標籤兩種元件。RFID讀寫器必須 藉由天線發射電磁波，以傳送訊號，同時RFID標籤接收 RFID讀寫器訊號後，再發射出標籤訊號，再被犯1£)讀寫器 所接收。目前在開發RFID系統時有些問題至今仍無法有效 的解決，其一就是RFID讀寫器與rFID標籤的天線場型無法 準確的得知，造成必須僅以嘗試錯誤的方式找尋最佳之貼 標點。另外對場型無法掌握，造成有效距離不夠，卻不知 如何改善的窘境。因此為了提升讀取率與讀取距離，必須 對於天線％型進行隶佳化設計。此外，讀取率與讀取距離 也與RFID標籤的黏貼位置有關。關於天線場型的量測，若 以傳統天線進行量測，由於天線本身以及傳輸線所含的金 屬會造成頃寫器與標戴天線場型的巨大變化，無法真實得 102549.doc ‘1270676 知工作時的實際場型與波形。 傳統里測RFID讀寫器天線場型都以一般傳統接收天 線然後以纜線傳送電訊號至信號處理器。但以纜線傳送 訊號時，會影響到接收天線所在處的電磁場強度，導致量 ’貝J出的場型不精確。尤其當接收天線靠近RFID讀寫器時， 兩者會產生彼此作用，使得精確地量測場型更為困難。 另外在量測RFID標籤的天線場型時，必須面對過去前所 未有的困難。由於RFID標籤在工作時是感應111?11)讀寫器所 發射的訊號，經激發RFID標籤的晶片，再產生訊號由天線 發射出去，所以本身並沒有饋入線，若是以傳統的方式， 必須先移除晶片，再以傳輸線饋入訊號至天線，再進行場 型量測，但RFID標籤的天線相對於傳輸線在尺寸上相對而 。小很夕，因此天線的原始場型會被大幅的改變，因此量 測結果與實際工作場型有很大的不同。 一般電磁輻射源的場型量測通常都是在微波暗室中進行 且無法自動調整待測電磁輻射源及感測器之相對位置。然 RFID系統均是運用在開放空間環境，例如：大賣場或工廠 之供應鏈與物流管理、工廠之生產製造與裝配、航空公司 或郵局之行李郵件和包裹處理等，使得RFID系統在操作時 均曝露在外界輻射干擾之下。為能實際地、快速地量測出 處於操作環境中之RFID讀寫器及RFID標籤天線場型，因此 有必要發展出可運用於開放空間、方便於現場（〇n_site)實施 及避免習知技藝於量測時對待測天線場型所造成的失真之 電磁訊號量測系統。 102549.doc Ί27Ό676 【發明内容】 本發明之目的係提供一種電磁訊號量測系統，藉由低干 擾電磁％感測技術及自動定位機構，於開放空間中現場量 測RFID讀寫器及RFID標籤之天線場型。該低干擾電磁場感 測技術係‘光调制散射振子（〇ptically modulated scatterer，OMS)或光電型電磁場感應器（〇ptic electdc fiddΊ270676 IX. Description of the Invention: [Technical Field] The present invention relates to an electromagnetic signal measuring system, in particular to an electromagnetic signal measuring system based on a low-interference electromagnetic field sensing technology and an automatic positioning mechanism, which is particularly suitable for use. Antenna field measurement at the open space site (〇n_site), such as RFID reader (Reader) and RFID tag (Tag) antenna field measurement. The invention further relates to an electromagnetic signal measuring method for use in the above measuring system. [Prior Art] The development of Radio Frequency Identification (RFID) is a global concern. It has been optimistic that it can replace barcodes in a large amount, and the market demand in the future will be quite amazing. The RFID system mainly includes two components: an RFID reader and an RFID tag. The RFID reader must transmit electromagnetic waves through the antenna to transmit signals. At the same time, the RFID tag receives the RFID reader signal and then transmits the tag signal, which is then received by the reader. At present, some problems in the development of RFID systems are still not solved effectively. One is that the antenna type of the RFID reader and the rFID tag cannot be accurately known, and it is necessary to find the best punctuation point only by trying the wrong way. In addition, the field type cannot be mastered, resulting in an insufficient effective distance, but does not know how to improve the dilemma. Therefore, in order to increase the read rate and the read distance, it is necessary to perform a better design for the antenna % type. In addition, the read rate and read distance are also related to the adhesive position of the RFID tag. Regarding the measurement of the antenna field type, if the measurement is carried out by a conventional antenna, the antenna itself and the metal contained in the transmission line may cause a huge change in the field type of the writer and the antenna, so that it is impossible to obtain the actual work. 102549.doc '1270676 Actual field type and waveform at the time. Traditionally, the RFID reader antenna field type is generally received by the antenna and then transmitted by cable to the signal processor. However, when the signal is transmitted by cable, it will affect the intensity of the electromagnetic field where the receiving antenna is located, resulting in an inaccurate field size. Especially when the receiving antenna is close to the RFID reader, the two interact with each other, making it more difficult to accurately measure the field. In addition, when measuring the antenna pattern of an RFID tag, it is necessary to face unprecedented difficulties in the past. Since the RFID tag is in operation to sense the signal emitted by the reader 111?11), the chip that excites the RFID tag is regenerated and transmitted by the antenna, so there is no feed line itself. In the traditional way, it must first The chip is removed, and the signal is fed to the antenna by the transmission line, and field type measurement is performed, but the antenna of the RFID tag is relatively opposite in size with respect to the transmission line. It is very small, so the original field type of the antenna will be greatly changed, so the measurement results are very different from the actual working field type. The field type measurement of the general electromagnetic radiation source is usually performed in the microwave darkroom and the relative position of the electromagnetic radiation source and the sensor to be tested cannot be automatically adjusted. However, RFID systems are used in open space environments, such as supply chain and logistics management in hypermarkets or factories, manufacturing and assembly of factories, baggage mail and parcel processing at airlines or post offices, etc. Exposure to external radiation interference. In order to accurately and quickly measure the RFID reader and RFID tag antenna field type in the operating environment, it is necessary to develop an open space, facilitate on-site (〇n_site) implementation and avoid conventional skills. An electromagnetic signal measurement system for measuring distortion caused by an antenna field during measurement. 102549.doc Ί27Ό676 SUMMARY OF THE INVENTION The object of the present invention is to provide an electromagnetic signal measuring system for measuring RFID readers and RFID tags in an open space by means of low-interference electromagnetic % sensing technology and automatic positioning mechanism. Antenna field type. The low-interference electromagnetic field sensing technology is ‘pically modulated scatterer (OMS) or photoelectric type electromagnetic field sensor (〇ptic electdc fidd)
sensor，OEFS)之技術。自動定位機構則利用兩載台及位置 控制器以自動量測天線之場型。 不赞明之第一實施例揭 號量測系統，其包含一待測發射源（例如RFID讀寫器）以 及一光電型電磁場感測器。光電型電磁場感測器該光電型 電磁場感測器係用以感測該待測發射源產生之電磁訊號 其包含-電射光源，可產生—電射光束；—電光晶體基板； 一光輸入波導及一光輸出波導，二者均設置於該電光晶體 基板中；至少-光調變波導，設置於該電光晶體基板中且 連接該光輸人波導及該光輸出料；__第—光纖，用以連 接該電光晶體基板及該電射光源；一光偵測器，用以偵測 該干涉光之強度；一第二光纖’連接該電光晶體基板與該 光偵測器以及-感測電極，置於電光晶體基板表面上，可 感測該待測發射源之電磁訊號，並施加_電場於該光調變 波導。此外，該電磁訊號量測系統另包含一第一載台及一 第二載台。該第一載台係用以承載該待測發射源；：第二 載台係用以承載該光電型電磁場感測器。 本發明之第二實施例揭示-種電磁訊號量測系統，其包 102549.doc Ί27Ό676 含一發射天線、一散射元件（例如RFID標籤）、一調制電路、 一光源、一接收天線、一同步檢測電路以及一訊號處理電 路。該散射元件係用以調制並散射該發射天線產生之電磁 訊號以產生一調制散射波訊號。該調制電路係用以產生一 電調制訊號。該光源則根據該電調制訊號產生一光調制訊 號。該接收天線係用以接收該調制散射波訊號。該同步檢 測電路係用以檢測該電調制訊號及該調制散射波訊號。該 訊號處理電路係電氣連接於該同步檢測電路，用以計算該 調制散射波訊號之振幅及相位。此外，該電磁訊號量測系 統另包含一第一載台及一第二載台。該第一載台係用以承 載該散射元件，該第二載台係用以承載該發射天線。在第 二實施例中，係以發射天線發射訊號至RFID標籤，但由於 散射訊號相當微弱，因此將採用光調制散射振子的技術， 以一光開關取代原有RFID標籤的晶片，以調制的光源控制 其開啟或關閉，而調制散射體的截面積，從而調制散射波， 再應用同步接收的技術將散射波從電磁場背景雜訊中粹取 出來，達到量測RFID標籤天線場形之目的。 本發明之第三實施例揭示一種電磁訊號量測系統，其包 含、一待測發射源（例如RFID讀寫器）、一調制電路、一光 源、一光調制散射振子、一接收天線、一同步檢測電路以 及一訊號處理電路。該調制電路係用以產生一電調制訊 號。該光源則根據該電調制訊號產生一光調制訊號。該光 調制散射振子係用以調制並散射該待測發射源產生之一電 磁訊號並產生一調制散射波訊號。該天線係用以接收該調 102549.doc '1270676 制後的電磁訊號。該同步檢測電路係用以檢測該電調制訊 就及該調制散射波訊號。該訊號處理電路係電氣連接於該 同步檢測電路，用以計算該電磁訊號之振幅及相位。此外， 該電磁訊號量測系統另包含一第一載台及一第二載台。該 第一載台係用以承載該待測發射源；該第二載台係用以承 載該光調制散射振子。 此外’本發明揭示之三個實施例為能達到於開放空間中 鲁現場量測RFID讀寫器及RFID標籤天線場型之目的，均不需 操作於一微波暗室中且均運用自動定位機構來精準定位 RFID讀寫器及RFID標籤以能快速量測出其天線場型。 就本發明之電磁訊號量測方法之第一個方法實施例而 • 言，首先提供一發射源，例如RFID讀寫器，以發射一待測 電磁波。另提供一感測器，例如光電型電磁場感測器，以 偵測該待測電磁波。所偵測到之待測電磁波於該感測器上 產生一電場以改變來自同一光源之二光束之光程以形成一 • +涉光。藉由計算該干涉光之相位及振幅，以得出該待測 電磁波之電場強度。量測完在該感測器位置之待測電磁波 電場強度之後，再改變該感測器與該發射源之相對位置， 重覆進行上述之量測步驟，直到獲得所需之發射源天線場 型為止。 就本發明之電磁訊號量測方法之第二個方法實施例而 言，首先提供-發射源，以發射一待測電磁波。另提供一 感測器，例如光調制散射振子，以偵測該待測電磁波。利 用-光調制訊號於該感測器上將該待測電磁波轉換成一調 102549.doc -10- 1270676 制散射波訊號。之後於與該感測器距一固定距離處接收該 调制散射波訊號，並配合一產生該光調制訊號之電調制訊 號’計算出該調制散射波訊號之相位及振幅。之後再改變 該感測器與該發射源之相對位置，重覆進行上述之量測步 驟，直到獲得所需之感測器天線場型為止。在本方法實施 例中，該感測器係一 RFID標籤，其内部晶片已由一光開關 取代；而該發射源可為一 RFID讀寫器。 鲁就本發明之電磁訊號量測方法之第三個方法實施例而 言，首先提供一發射源，以發射一待測電磁波。另提供一 感測器，例如光調制散射振子，以偵測該待測電磁波。利 用一光調制訊號於該感測器上將該待測電磁波轉換成一調 • 制散射波訊號。利用一產生該光調制訊號之電調制訊號， 計算出該感測器所在處之該待測電磁波之相位及振幅。之 後再改變該感測器與該發射源之相對位置，重覆進行上述 之量測步驟，直到獲得所需之發射源天線場型為止。 • 【實施方式】 以下配合圖式詳細說明本發明之電磁訊號量測系統及其 工作原理。 圖1係本發明第一實施例之電磁訊號量測系統100之示意 圖。該電磁訊號量測系統100包含一第一載台11〇、一設置 於該第一載台110上之待測發射源112、一第二載台120以及 一設置於該第二載台120上之光電型電磁場感測器10。該光 電型電磁場感測器10則可感測該待測發射源112產生之電 磁訊號。該電磁訊號量測系統10 0可另包含一位置控制器 102549.doc -11- •1270676 104，用以控制該第一載台π〇與該第二載台12〇之相對位 置’亦即控制該待測發射源112與該光電型電磁場感測器j 〇 之相對位置。較佳地，該第一載台11 〇係一升降旋轉載台。 該第二載台120包含一水平滑軌122、一設置於該水平滑軌 122上之直立滑軌124以及一設置於該直立滑軌124上之平 台126，其中該光電型電磁場感測器1〇係承載於該平台126 上。藉由該位置控制器104控制該第一載台11〇之旋轉角度 與該第二載台120之水平位置及高度。該待測發射源112可 為一 RFID讀寫器。 圖2例示圖1之光電型電磁場感測器1 〇之一實施例。該光 電型電磁場感測器10包含一晶體基板12、一設置於該晶體 基板12中之光輸入波導14、一設置於該晶體基板12中之光 輸出波導16、一設置於該晶體基板12中且連接該光輸入波 導14與該光輸出波導16之光調變波導18 A及18B、一設置於 該晶體基板12表面之感測電極22。自一雷射光源2〇發出之 雷射光束自一輸入光纖26導入該光輸入波導14並分光進入 該光調變波導18A及18B後，再合併到該光輸出波導16。其 中，該晶體基板12可為一鈮酸鋰基板。 圖3係圖2所示之光電型電磁場感測器1〇沿a-a線之剖面 圖。該感測電極22係由二條設置於該光調變波導isA及18B 上方之金屬導電線段24A及24B構成’其可感測該待測發射 源112之電場並施加一相應電場於該光調變波導丨8 a及 18B。光束在介質中之傳播速度係隨著介質之折射率增加而 減少。當該金屬導電線段24 A及24B之間有電壓差（即有電場 102549.doc • 12 - Ί270676 產生）時，則造成該光調變波導18A及18B之折射率改變，使 得行經該光調變波導18A及18B之雷射光束之光程改變，因 此該雷射光束自該光調變波導18A及18B進入該光輸出波 導16時將形成一干涉光，而該干涉光之相位及振幅將隨該 金屬導電線段24A及24B間之電位差而變化。復參圖！及圖 2,該干涉光係經由一輸出光纖28傳送至一光偵測器30將該 干涉光之相位及振幅轉換成一電訊號，再經由一訊號處理 器32計算該待測發射源112產生之電場。簡言之，該光電型 電磁場感測器10可視為一光調制器，當該感測電極22感測 到來自該待測發射源112之電場時，該光電型電磁場感測器 1 〇即根據感測之電場強度與相位調制該光輸出波導丨6輸出 之干涉光的相位及振幅。因此，該感測電極22感測之電場 強度在該光電型電磁場感測器1〇上即可轉換成光訊號，再 經由該輸出光纖28傳送至該光偵測器30，而不需要用電緵 線連接’可解決習知使用電纜線傳送訊號所產生的干擾問 題。 圖4例示圖1之光電型電磁場感測器1〇之另一實施例。該 光電型電磁場感測器1〇,包含一光調制器5〇以及一感測元件 70。相較於圖2所示之光電型電磁場感測器1〇使用内建式感 測電極22,圖4之之光電型電磁場感測器1〇，使用一外掛式偶 極感測電極（即該感測元件7〇)。除了在該光調變波導丨8 A及 18B外侧邊各設置一電極52A及52B以及在該電極52A及 52B之間設置一電極54外，該光調制器5〇之結構大體上相似 於圖2所示之光電型電磁場感測器10，可依施加的電場改變 102549.doc -13- 1270676 經其傳送之光束光程。該感測元件70可感測該待測發射源 112之電場，並施加一電位差於該光調制器5〇之電極52A、 52B及電極54。當該感測元件70感測到該待測發射源112之 電磁訊號後，即在該電極52A、52B及54之間施加一相應該 電場訊號之電位差。該感測元件70包含一第一導電線段 71、一設置於該第一導電線段71之一末端的第一光開關 74、 一設置於第一導電線段71之另一末端的第二光開關 75、 一經由第一光開關74與該第一導電線段71連接之第二 導電線段72、一經由該第二光開關75與該第一導電線段7丄 連接之第三導電線段73。當該感測元件70感測到該待測發 射源112之電磁訊號後，即在該電極52A、52B及54之間施 加一相應該電場訊號之電位差。 當該第一光開關74及該第二光開關75導通時，該第一導 電線段71、該第二導電線段72及該第三導電線段73即形成 一可感測磁場訊號之環形天線，而當該第一光開關74及該 第二光開關75不導通時，該第二導電線段72及該第三導電 線段73即形成一可感測電場訊號之線形天線。光纖76及77 係用以傳送控制第一光開關74及第二光開關75之開關訊 號。較佳地，該感測元件70係一偶極天線。 圖5係本發明第二實施例之電磁訊號量測系統2〇〇之示意 圖。該電磁訊號量測系統200包含一第一載台210、一設置 於該第一載台210上之散射元件240、一第二載台220以及一 設置於該第二載台220上之發射天線230、一用以產生一電 調制訊號之調制電路270、一電氣連接於該調制電路270之 102549.doc -14- 1270676 雷射光源260、一接收天線250、一電氣連接於該接收天線 250之同步檢測電路290以及一電氣連接於該同步檢測電路 290之訊號處理電路295,其中該接收天線250與該散射元件 240之相對位置固定。該雷射光源260根據該電調制訊號產 生一光調制訊號，而散射元件240則根據該光調制訊號將發 射天線230所產生一電磁訊號轉換成一調制散射波訊號。該 調制散射波訊號經該接收天線250接收後傳送至該同步檢 測電路290，該同步檢測電路290再從該調制散射波訊號及 該電調制訊號產生具有90度相位差之一第一相位訊號！及 一第二相位訊號Q。該第一相位訊號I與該電調制訊號係同 相位，而該第二相位訊號Q則與該電調制訊號具有9〇度之相 位差。该訊號處理電路295則根據該第一相位訊號及該第二 相位訊號計算該散射元件240所散射出該調制散射波訊號 之振幅及相位。該發射天線230可為一 RFID讀寫器。該散射 元件240可為一 RFID標籤。另，該雷射光源26〇亦可以D (Light Emitting Diode)或其他光源取代。 名電磁訊號量測系統200可另包含一位置控制器“ο，用 以控制該第一載台210與該第二載台22〇之相對位置，亦即 控制該發射天線230與該散射元件24〇之相對位置。較佳 地，該第一載台210係一旋轉載台。該第二載台22〇包含一 水平滑執222、一設置於該水平滑軌222上之直立滑執224 以及一設置於該直立滑軌224上之平台226，其中該發射天 線230係承載於該平台226上。藉由該位置控制器⑽控制該 第一載台210之旋轉角度與該第二載台22〇之水平位置及高 102549.doc -15- 1270676 度。因此該散射元件240若為一 RFID標籤天線替代，則該電 磁訊號量測裝置200可以用來量測RFID標籤天線之場型特 性。 圖6係圖5中散射元件240之一實施例示意圖，係以一 RFID標籤天線為例。該散射元件240包含一設於一基板242 之下表面之天線244、一連接該天線244之光開關246、一用 以傳送該光調制訊號之光纖248，該天線244係由一第一導 > 線段244a及一第二導線段244b所組成。該光纖248之一端係 對準該光開關246，而另一端則耦合於該雷射光源260 (參 圖5 )以將該光調制訊號傳送至該光開關246。 圖7係圖6之光開關246之示意圖。該光開關246包含一本 質砷化鎵基板246a、一高掺雜砷化鎵基板246b、一設置於 該高摻雜砷化鎵基板246b上之第一電極246c及第二電極 246d。該第一電極246c及該第二電極246d係分別連接該第 一導線段244a及該第二導線段244b。該第一電極246c與該 > 第二電極246d係呈指叉交錯之方式排列，而該光纖248係對 準該光開關246呈指叉交錯之區域。該高摻雜砷化鎵基板 246b可為P型或N型，且其與該第一電極246c及該第二電極 246d係呈歐姆接觸。當具有適當能量之光束照射在該光開 關246呈指叉交錯狀排列之區域時，將產生電子-電洞對使 得該光開關246之第一電極246c及第二電極246d間之電阻 降低，甚至導通該第一電極246c及該第二電極246d，進而 使得第一導線段244a及該第二導線段244b耦合變成一個較 長的金屬散射體。如此，即可增加整體之散射截面，以增 102549.doc -16- 1270676 強散射元件240所發出的散射波訊號。 圖8係本發明第三實施例之電磁訊號量測系統500之示意 圖。該電磁訊號量測系統500包含一第二載台220、一設置 於該第二載台220上之光調制散射振子510、一第一載台 210、一設置於該第一載台210上之發射源520、一用以產生 一電調制訊號之調制電路270、一電氣連接於該調制電路 270之雷射光源260、一接收天線250、一電氣連接於該接收 • 天線250之同步檢測電路290以及一電氣連接於該同步檢測 電路290之訊號處理電路295。 該電磁訊號量測系統500可另包含一位置控制器280，用 以控制該第一載台210與該第二載台220之相對位置，亦即 •控制該發射源520與該光調制散射振子5 1〇之相對位置。較 佳地，該第一載台210係一旋轉載台。該第二載台22〇包含 一水平滑軌222、一設置於該水平滑軌222上之直立滑軌224 以及一設置於該直立滑軌224上之平台226，其中該光調制 • 散射振子5 10係承載於該平台226上。藉由該位置控制器28〇 控制該第一載台820之旋轉角度與該第二載台22〇之水平位 置及高度，該電磁訊號量測裝置500可量測該發射源52〇之 天線場型。該發射源520可為一RFID讀寫器。另，該雷射光 源亦可以LED或其他光源取代。 該雷射光源260根據該電調制訊號產生一光調制訊號，而 該光調制散射振子510則可根據該光調制訊號將發射源52〇 所產生一電磁訊號轉換成一調制散射波訊號。該調制散射 波訊號經該接收天線250接收後傳送至該同步檢測電路 102549.doc -17- Ί270676 290，該同步檢測電路290再從該調制散射波訊號及該電調 制訊號產生具有90度相位差之一第一相位訊號I及一第二 相位訊號Q。該第一相位訊號I與該電調制訊號係同相位， 而該第二相位訊號q則與該電調制訊號具有90度之相位 差。該訊號處理電路295則根據該第一相位訊號及該第二相 位訊號計算該光調制散射振子5 10所在處的發射源520發射 出之電磁訊號振幅及相位。 圖9係圖8中之光調制散射振子5 10之一實施例。該光調制 散射振子510之結構基本上與圖6之散射元件240相同，另外 包含一用以將光纖248固定於該基板242上表面之套管 249。該套管249可防止光纖248在第二載台220運動時自該 基板242表面脫落。 相較於習知技藝之缺點，即於量測時金屬傳輸線對待測 天線場型所造成的失真、須將天線置於封閉空間（例如微波 暗室）中量測及無法自動量測天線場型等，本發明所揭示之 第一實施例係運用光電型電磁場感應器技術，第二及第三 實施例係運用光調制散射振子技術且三實施例均使用光纖 傳遞調制訊號以避免習知技藝對待測天線場型所造成的失 真。另本發明可直接於開放空間之現場實施且可利用自動 定位機構自動量測出天線場型，因此本發明確可達到預期 之目的。此外，RFID系統因操作於開放空間，因此本發明 特別適用於開放空間中之現場RFID讀寫器及RFID標鐵天 線場型量測。然本發明之電磁訊號量測系統亦可使用在封 閉空間（例如微波暗室）中。 102549.doc -18- !27〇676 本發明之技術内容及技術特點已揭示如上，然而熟悉本 項技術之人士仍可能基於本發明之教示及揭示而作種種不 背離本發明精神之替換及修飾。因此，本發明之保護範圍 應不限於實施例所揭示者，而應包括各種不背離本發明之 替換及修飾，並為以下之申請專利範圍所涵蓋。 【圖式簡單說明】Sensor, OEFS) technology. The automatic positioning mechanism uses two stages and a position controller to automatically measure the field pattern of the antenna. The first embodiment, which is not appreciated, discloses a measurement system comprising a source to be tested (e.g., an RFID reader) and a photoelectric type electromagnetic field sensor. Photoelectric type electromagnetic field sensor for sensing electromagnetic signals generated by the emission source to be tested, comprising: an electric light source, capable of generating an electron beam; an electro-optic crystal substrate; an optical input waveguide And an optical output waveguide, both of which are disposed in the electro-optical crystal substrate; at least the optical modulation waveguide is disposed in the electro-optic crystal substrate and is connected to the optical input waveguide and the optical output material; For connecting the electro-optical crystal substrate and the electro-optic light source; a photodetector for detecting the intensity of the interference light; a second optical fiber 'connecting the electro-optical crystal substrate to the photodetector and the sensing electrode And being placed on the surface of the electro-optical crystal substrate, the electromagnetic signal of the emission source to be tested is sensed, and an electric field is applied to the optical modulation waveguide. In addition, the electromagnetic signal measuring system further comprises a first stage and a second stage. The first stage is used to carry the emission source to be tested; the second stage is used to carry the photoelectric type electromagnetic field sensor. A second embodiment of the present invention discloses an electromagnetic signal measuring system, and the package 102549.doc Ί27Ό676 includes a transmitting antenna, a scattering element (such as an RFID tag), a modulation circuit, a light source, a receiving antenna, and a synchronous detection. Circuit and a signal processing circuit. The scattering element is configured to modulate and scatter electromagnetic signals generated by the transmitting antenna to generate a modulated scattered wave signal. The modulation circuit is for generating an electrical modulation signal. The light source generates an optical modulation signal based on the electrical modulation signal. The receiving antenna is configured to receive the modulated scattered wave signal. The synchronous detection circuit is configured to detect the electrical modulation signal and the modulated scattered wave signal. The signal processing circuit is electrically connected to the synchronization detecting circuit for calculating the amplitude and phase of the modulated scattered wave signal. In addition, the electromagnetic signal measuring system further comprises a first stage and a second stage. The first stage is for carrying the scattering element, and the second stage is for carrying the transmitting antenna. In the second embodiment, the transmitting antenna transmits a signal to the RFID tag, but since the scattered signal is rather weak, the light modulation diffusing oscillator technology is used to replace the original RFID tag wafer with an optical switch to modulate the light source. Controlling its turn-on or turn-off, and modulating the cross-sectional area of the scatterer, thereby modulating the scattered wave, and then applying the technique of synchronous reception to extract the scattered wave from the background noise of the electromagnetic field to achieve the purpose of measuring the field shape of the RFID tag antenna. A third embodiment of the present invention discloses an electromagnetic signal measuring system, comprising: a transmitting source to be tested (for example, an RFID reader), a modulation circuit, a light source, a light modulation scattering oscillator, a receiving antenna, and a synchronization. A detection circuit and a signal processing circuit. The modulation circuit is for generating an electrical modulation signal. The light source generates a light modulation signal according to the electrical modulation signal. The light-modulating scattered oscillator is used to modulate and scatter the electromagnetic signal generated by the source to be tested to generate a modulated scattered wave signal. The antenna is used to receive the electromagnetic signal after the adjustment of 102549.doc '1270676. The synchronous detection circuit is configured to detect the electrical modulation signal and the modulated scattered wave signal. The signal processing circuit is electrically connected to the synchronization detecting circuit for calculating the amplitude and phase of the electromagnetic signal. In addition, the electromagnetic signal measuring system further includes a first stage and a second stage. The first stage is for carrying the emission source to be tested; the second stage is for carrying the light modulation scattering oscillator. In addition, the three embodiments disclosed in the present invention are capable of achieving the purpose of measuring the RFID reader/writer and the RFID tag antenna field in the open space, and do not need to operate in a microwave darkroom and both use an automatic positioning mechanism. Accurately locate RFID readers and RFID tags to quickly measure their antenna pattern. In connection with the first method embodiment of the electromagnetic signal measurement method of the present invention, a source, such as an RFID reader, is first provided to emit an electromagnetic wave to be measured. A sensor, such as a photoelectric type electromagnetic field sensor, is further provided to detect the electromagnetic wave to be measured. The detected electromagnetic wave to be detected generates an electric field on the sensor to change the optical paths of the two beams from the same source to form a +-light. The electric field strength of the electromagnetic wave to be measured is obtained by calculating the phase and amplitude of the interference light. After measuring the electric field strength of the electromagnetic wave to be measured at the position of the sensor, changing the relative position of the sensor and the emission source, repeating the above measuring step until the desired source antenna field type is obtained. until. With regard to the second method embodiment of the electromagnetic signal measuring method of the present invention, an -transmitting source is first provided to emit an electromagnetic wave to be measured. A sensor, such as a light modulating scattering oscillator, is also provided to detect the electromagnetic wave to be measured. The electromagnetic wave to be measured is converted into a modulated 102549.doc -10- 1270676 scattered wave signal by using the optical modulation signal on the sensor. Then, the modulated scattered wave signal is received at a fixed distance from the sensor, and the phase and amplitude of the modulated scattered wave signal are calculated in conjunction with an electrical modulated signal that generates the optical modulated signal. The relative position of the sensor to the source is then changed, and the measurement step described above is repeated until the desired sensor antenna pattern is obtained. In the embodiment of the method, the sensor is an RFID tag whose internal chip has been replaced by an optical switch; and the source can be an RFID reader. In the third method embodiment of the electromagnetic signal measuring method of the present invention, a transmitting source is first provided to emit an electromagnetic wave to be measured. A sensor, such as a light modulating scattering oscillator, is also provided to detect the electromagnetic wave to be measured. The electromagnetic wave to be measured is converted into a modulated scattered wave signal by the optical modulation signal on the sensor. The phase and amplitude of the electromagnetic wave to be measured at the location of the sensor are calculated by using an electrical modulation signal that generates the optical modulation signal. Thereafter, the relative position of the sensor to the source is changed, and the above measuring step is repeated until the desired source antenna field pattern is obtained. • [Embodiment] The electromagnetic signal measuring system of the present invention and its working principle will be described in detail below with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic illustration of an electromagnetic signal measuring system 100 in accordance with a first embodiment of the present invention. The electromagnetic signal measuring system 100 includes a first stage 11 , a to-be-tested emission source 112 disposed on the first stage 110 , a second stage 120 , and a second stage 120 disposed on the second stage 120 . Photoelectric electromagnetic field sensor 10. The photoelectric type electromagnetic field sensor 10 senses the electromagnetic signal generated by the emission source 112 to be tested. The electromagnetic signal measuring system 100 can further include a position controller 102549.doc -11- • 1270676 104 for controlling the relative position of the first stage π 〇 and the second stage 12 ' The relative position of the emission source 112 to be tested and the photoelectric type electromagnetic field sensor j 〇. Preferably, the first stage 11 is a lifting and lowering rotation stage. The second stage 120 includes a horizontal slide rail 122, an upright slide rail 124 disposed on the horizontal slide rail 122, and a platform 126 disposed on the vertical slide rail 124. The photoelectric type electromagnetic field sensor 1 The tether is carried on the platform 126. The positional controller 104 controls the rotation angle of the first stage 11 and the horizontal position and height of the second stage 120. The to-be-tested emission source 112 can be an RFID reader/writer. Fig. 2 illustrates an embodiment of the photoelectric type electromagnetic field sensor 1 of Fig. 1. The photoelectric type electromagnetic field sensor 10 includes a crystal substrate 12, an optical input waveguide 14 disposed in the crystal substrate 12, a light output waveguide 16 disposed in the crystal substrate 12, and a crystal output substrate 12 disposed in the crystal substrate 12. The optical input waveguide 14 and the optical modulation waveguides 18 A and 18B of the optical output waveguide 16 and a sensing electrode 22 disposed on the surface of the crystal substrate 12 are connected. A laser beam emitted from a laser source 2 is introduced into the optical input waveguide 14 from an input fiber 26 and split into the optical modulation waveguides 18A and 18B, and then incorporated into the optical output waveguide 16. The crystal substrate 12 can be a lithium niobate substrate. Figure 3 is a cross-sectional view of the photoelectric type electromagnetic field sensor 1 shown in Figure 2 taken along line a-a. The sensing electrode 22 is composed of two metal conductive segments 24A and 24B disposed above the optical modulation waveguides isA and 18B, which can sense the electric field of the emission source 112 to be tested and apply a corresponding electric field to the optical modulation. Waveguides 8a and 18B. The propagation velocity of the beam in the medium decreases as the refractive index of the medium increases. When there is a voltage difference between the metal conductive segments 24 A and 24B (that is, an electric field 102549.doc • 12 - Ί 270676 is generated), the refractive index of the optical modulation waveguides 18A and 18B is changed, so that the light modulation is performed. The optical paths of the laser beams of the waveguides 18A and 18B are changed. Therefore, when the laser beam enters the optical output waveguide 16 from the optical modulation waveguides 18A and 18B, an interference light is formed, and the phase and amplitude of the interference light will follow. The potential difference between the metal conductive segments 24A and 24B changes. Repetition chart! 2, the interference light is transmitted to a photodetector 30 via an output fiber 28 to convert the phase and amplitude of the interfering light into an electrical signal, and then calculated by the signal processor 32 by the signal processor 32. electric field. In short, the photoelectric type electromagnetic field sensor 10 can be regarded as a light modulator. When the sensing electrode 22 senses an electric field from the emission source 112 to be tested, the photoelectric type electromagnetic field sensor 1 is The sensed electric field strength and phase modulate the phase and amplitude of the interference light output by the optical output waveguide 丨6. Therefore, the electric field intensity sensed by the sensing electrode 22 can be converted into an optical signal on the photoelectric type electromagnetic field sensor 1 , and then transmitted to the photodetector 30 via the output optical fiber 28 without using electricity. The twisted wire connection can solve the interference problem caused by the conventional use of the cable to transmit signals. Fig. 4 illustrates another embodiment of the photoelectric type electromagnetic field sensor 1 of Fig. 1. The photoelectric type electromagnetic field sensor 1A includes a light modulator 5A and a sensing element 70. Compared with the photoelectric type electromagnetic field sensor 1 shown in FIG. 2, the built-in sensing electrode 22 is used, and the photoelectric type electromagnetic field sensor 1 of FIG. 4 uses an external dipole sensing electrode (ie, the Sensing element 7〇). The optical modulator 5A is substantially similar in structure to the optical modulators 8A and 18B except that an electrode 52A and 52B are disposed on the outer side and an electrode 54 is disposed between the electrodes 52A and 52B. The photoelectric type electromagnetic field sensor 10 shown can change the beam path length through which 102549.doc - 13 - 1270676 is transmitted according to the applied electric field. The sensing component 70 senses the electric field of the emission source 112 to be tested and applies a potential difference to the electrodes 52A, 52B and the electrode 54 of the optical modulator 5. When the sensing component 70 senses the electromagnetic signal of the emission source 112 to be tested, a potential difference corresponding to the electric field signal is applied between the electrodes 52A, 52B and 54. The sensing component 70 includes a first conductive line segment 71, a first optical switch 74 disposed at one end of the first conductive line segment 71, and a second optical switch 75 disposed at the other end of the first conductive line segment 71. a second conductive line segment 72 connected to the first conductive line segment 71 via the first optical switch 74, and a third conductive line segment 73 connected to the first conductive line segment 7 via the second optical switch 75. When the sensing component 70 senses the electromagnetic signal of the source 112 to be tested, a potential difference corresponding to the electric field signal is applied between the electrodes 52A, 52B and 54. When the first optical switch 74 and the second optical switch 75 are turned on, the first conductive line segment 71, the second conductive line segment 72 and the third conductive line segment 73 form a loop antenna capable of sensing a magnetic field signal, and When the first optical switch 74 and the second optical switch 75 are not turned on, the second conductive line segment 72 and the third conductive line segment 73 form a linear antenna capable of sensing an electric field signal. The optical fibers 76 and 77 are used to transmit switching signals for controlling the first optical switch 74 and the second optical switch 75. Preferably, the sensing element 70 is a dipole antenna. Fig. 5 is a schematic view showing the electromagnetic signal measuring system 2 of the second embodiment of the present invention. The electromagnetic signal measuring system 200 includes a first stage 210, a scattering element 240 disposed on the first stage 210, a second stage 220, and a transmitting antenna disposed on the second stage 220. 230, a modulation circuit 270 for generating an electrical modulation signal, a 102549.doc -14-1270676 laser source 260 electrically connected to the modulation circuit 270, a receiving antenna 250, and an electrical connection to the receiving antenna 250 The synchronization detection circuit 290 and a signal processing circuit 295 electrically connected to the synchronization detection circuit 290, wherein the relative position of the receiving antenna 250 and the scattering element 240 are fixed. The laser source 260 generates an optical modulation signal according to the electrical modulation signal, and the scattering component 240 converts an electromagnetic signal generated by the transmitting antenna 230 into a modulated scattered wave signal according to the optical modulation signal. The modulated scattered wave signal is received by the receiving antenna 250 and transmitted to the synchronous detecting circuit 290. The synchronous detecting circuit 290 generates a first phase signal having a phase difference of 90 degrees from the modulated scattered wave signal and the electrical modulated signal! And a second phase signal Q. The first phase signal I and the electrical modulation signal are in phase, and the second phase signal Q has a phase difference of 9 degrees from the electrical modulation signal. The signal processing circuit 295 calculates the amplitude and phase of the modulated scattered wave signal scattered by the scattering element 240 based on the first phase signal and the second phase signal. The transmit antenna 230 can be an RFID reader. The scattering element 240 can be an RFID tag. Alternatively, the laser source 26 can be replaced by a D (Light Emitting Diode) or other light source. The electromagnetic signal measuring system 200 can further include a position controller "o" for controlling the relative position of the first stage 210 and the second stage 22, that is, controlling the transmitting antenna 230 and the scattering element 24. Preferably, the first stage 210 is a rotating stage. The second stage 22 includes a horizontal sliding 222, an upright sliding 224 disposed on the horizontal sliding rail 222, and a platform 226 disposed on the upright rail 224, wherein the transmitting antenna 230 is carried on the platform 226. The rotation angle of the first stage 210 and the second stage 22 are controlled by the position controller (10). The horizontal position of the crucible is as high as 102549.doc -15 - 1270676 degrees. Therefore, if the scattering element 240 is replaced by an RFID tag antenna, the electromagnetic signal measuring device 200 can be used to measure the field characteristics of the RFID tag antenna. 6 is a schematic diagram of an embodiment of the scattering element 240 in FIG. 5, taking an RFID tag antenna as an example. The scattering element 240 includes an antenna 244 disposed on a lower surface of a substrate 242, and an optical switch 246 connected to the antenna 244. One for transmitting the optical modulation signal The optical fiber 248 is composed of a first guiding segment 244a and a second segment 244b. One end of the optical fiber 248 is aligned with the optical switch 246, and the other end is coupled to the laser source 260. (See Fig. 5) to transmit the optical modulation signal to the optical switch 246. Figure 7 is a schematic diagram of the optical switch 246 of Figure 6. The optical switch 246 includes an intrinsic gallium arsenide substrate 246a, a highly doped gallium arsenide. a substrate 246b, a first electrode 246c and a second electrode 246d disposed on the highly doped GaAs substrate 246b. The first electrode 246c and the second electrode 246d are respectively connected to the first wire segment 244a and the first electrode segment 244a The two-wire segment 244b is arranged such that the first electrode 246c and the second electrode 246d are interdigitated in an interdigitated manner, and the optical fiber 248 is aligned with the optical switch 246 in an area where the interdigitated staggered region. The gallium substrate 246b may be P-type or N-type, and is in ohmic contact with the first electrode 246c and the second electrode 246d. When a light beam having an appropriate energy is irradiated on the optical switch 246, the interdigitated arrangement is arranged. In the region, an electron-hole pair will be generated such that the optical switch 246 is the first The resistance between the electrode 246c and the second electrode 246d is lowered, and even the first electrode 246c and the second electrode 246d are turned on, thereby coupling the first wire segment 244a and the second wire segment 244b into a longer metal scatterer. Thus, the overall scattering cross section can be increased to increase the scattered wave signal emitted by the strong scattering element 240 of the 102549.doc -16-1270676. Fig. 8 is a schematic diagram of the electromagnetic signal measuring system 500 of the third embodiment of the present invention. The electromagnetic signal measuring system 500 includes a second stage 220, a light modulation scattering vibrator 510 disposed on the second stage 220, a first stage 210, and a first stage 210 disposed on the first stage 210. The transmitting source 520, a modulation circuit 270 for generating an electrical modulation signal, a laser light source 260 electrically connected to the modulation circuit 270, a receiving antenna 250, and a synchronization detecting circuit 290 electrically connected to the receiving antenna 250 And a signal processing circuit 295 electrically connected to the synchronization detecting circuit 290. The electromagnetic signal measuring system 500 can further include a position controller 280 for controlling the relative position of the first stage 210 and the second stage 220, that is, controlling the emission source 520 and the light modulation scattering oscillator. 5 1〇 relative position. Preferably, the first stage 210 is a rotating stage. The second stage 22 includes a horizontal slide 222, an upright slide 224 disposed on the horizontal slide 222, and a platform 226 disposed on the vertical slide 224, wherein the light modulation/scattering vibrator 5 The 10 series is carried on the platform 226. The electromagnetic signal measuring device 500 can measure the antenna field of the transmitting source 52〇 by the position controller 28〇 controlling the rotation angle of the first stage 820 and the horizontal position and height of the second stage 22〇. type. The source 520 can be an RFID reader. Alternatively, the laser source can be replaced by an LED or other light source. The laser source 260 generates an optical modulation signal according to the electrical modulation signal, and the optical modulation scattering oscillator 510 converts an electromagnetic signal generated by the emission source 52A into a modulated scattered wave signal according to the optical modulation signal. The modulated scattered wave signal is received by the receiving antenna 250 and transmitted to the synchronous detecting circuit 102549.doc -17-Ί270676 290, and the synchronous detecting circuit 290 generates a phase difference of 90 degrees from the modulated scattered wave signal and the electrical modulated signal. One of the first phase signal I and one second phase signal Q. The first phase signal I is in phase with the electrical modulation signal, and the second phase signal q has a phase difference of 90 degrees from the electrical modulation signal. The signal processing circuit 295 calculates the amplitude and phase of the electromagnetic signal emitted by the emission source 520 where the optical modulation scattered vibrator 5 10 is located according to the first phase signal and the second phase signal. Figure 9 is an embodiment of the light modulated scattered oscillator 5 10 of Figure 8. The light-modulating scattered vibrator 510 is substantially identical in structure to the scattering element 240 of FIG. 6, and further includes a sleeve 249 for securing the optical fiber 248 to the upper surface of the substrate 242. The sleeve 249 prevents the optical fiber 248 from falling off the surface of the substrate 242 as the second stage 220 moves. Compared with the shortcomings of the prior art, the distortion caused by the metal transmission line to be measured during the measurement, the antenna must be placed in a closed space (such as a microwave darkroom) and the antenna field cannot be automatically measured. The first embodiment disclosed in the present invention utilizes a photoelectric type electromagnetic field sensor technology, and the second and third embodiments utilize a light modulation scattering oscillator technology, and the third embodiment uses an optical fiber to transmit a modulated signal to avoid the conventional technique to be tested. Distortion caused by the antenna field type. In addition, the present invention can be directly implemented in the field of an open space and the antenna pattern can be automatically measured by an automatic positioning mechanism, so that the present invention can achieve the intended purpose. In addition, since the RFID system operates in an open space, the present invention is particularly suitable for field RFID readers and RFID target wire field type measurement in open space. However, the electromagnetic signal measuring system of the present invention can also be used in a closed space (e.g., a microwave darkroom). </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> <RTIgt; . Therefore, the scope of the present invention should be construed as being limited by the scope of the appended claims. [Simple description of the map]
圖1係本發明之電磁訊號量測系統之第一實施例示意圖； 圖2例示圖1之光電型電磁場感測器之一實施例； 圖3係圖2所示之光電型電磁場感測器沿A-A線之剖面 圖； 圖4例示圖1之光電型電磁場感測器之另一實施例； 圖5係本發明之電磁訊號量測系統之第二實施例示意圖； 圖6係圖5之散射元件之一實施例示意圖； 圖7係圖6之光開關示意圖； 圖8係本發明之電磁訊號量測系統之第三實施例系意 圖；以及 圖9係圖8之光調制散射振子之一實施例示意圖。 【主要元件符號說明】 10、1(V光電型電磁場感測器12晶體基板 14 光輸入波導 18A、18B光調變波導 22 感測電極 26 輸入光纖 16 光輸出波導 20 雷射光源 24A、24B 金屬導電線段 28 輸出光纖 102549.doc 19- Ί270676 30 光偵測器 50 光調制器 70 感測元件 72 第二導電線段 74 第一光開關 Ί6、 77 光纖 104 位置控制器 112 待測發射源 122、 222 水平滑軌 126、 226 平台 230 發射天線 242 基板 244a 第一導線段 246 光開關 246b 高掺雜砷化鎵基板 246d 第二電極 249 套管 260 雷射光源 280 位置控制器 295 訊號處理電路 510 光調制散射振子 32 訊號處理器 52A > 52B、54 電極 71 第一導電線段 73 第三導電線段 75 第二光開關 100 電磁訊號量測系統 110、 210 第一載台 120、 220 第二載台 124、 224 直立滑軌 200 電磁訊號量測系統 240 散射元件 244 天線 244b 第二導線段 246a 本質砷化鎵基板 246c 第一電極 248 光纖 250 接收天線 270 調制電路 290 同步檢測電路 500 電磁訊號量測系統 520 發射源 102549.doc -20-1 is a schematic view of a first embodiment of an electromagnetic signal measuring system of the present invention; FIG. 2 is an embodiment of a photoelectric type electromagnetic field sensor of FIG. 1; FIG. 3 is a photoelectric type electromagnetic field sensor of FIG. Figure 4 illustrates another embodiment of the photoelectric type electromagnetic field sensor of Figure 1; Figure 5 is a schematic view of a second embodiment of the electromagnetic signal measuring system of the present invention; Figure 6 is a scattering element of Figure 5. FIG. 7 is a schematic view of an optical switch of FIG. 6; FIG. 8 is a third embodiment of the electromagnetic signal measuring system of the present invention; and FIG. 9 is an embodiment of the optical modulated diffusing oscillator of FIG. schematic diagram. [Main component symbol description] 10, 1 (V photoelectric type electromagnetic field sensor 12 crystal substrate 14 optical input waveguide 18A, 18B optical modulation waveguide 22 sensing electrode 26 input optical fiber 16 optical output waveguide 20 laser light source 24A, 24B metal Conductor segment 28 output fiber 102549.doc 19- Ί270676 30 photodetector 50 light modulator 70 sensing element 72 second conductive segment 74 first optical switch Ί6, 77 fiber 104 position controller 112 to be tested emission source 122, 222 Water smoothing rail 126, 226 platform 230 transmitting antenna 242 substrate 244a first wire segment 246 optical switch 246b highly doped gallium arsenide substrate 246d second electrode 249 sleeve 260 laser light source 280 position controller 295 signal processing circuit 510 light modulation Scattering vibrator 32 signal processor 52A > 52B, 54 electrode 71 first conductive line segment 73 third conductive line segment 75 second optical switch 100 electromagnetic signal measuring system 110, 210 first stage 120, 220 second stage 124, 224 Upright Rails 200 Electromagnetic Signal Measurement System 240 Scattering Element 244 Antenna 244b Second Wire Segment 246a Essential Gallium Arsenide 246c 500 520 emission source electromagnetic signal measuring system, the modulating circuit 270 receiving antenna synchronization detecting circuit 290 of the first optical fiber 250 102549.doc -20- electrode 248