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directional antenna 定向天線。

directional derivative

For the sake of the convenient network simulation , i select a same framework in my mac and routine protocols “ simulation , that is ieee802 . 11 standard built in soft tool opnet , by designing my network node model and directional antenna model , and the improvement of the current protocols , i realizes the evaluation of my special networks 為了方便網絡協議性能仿真,使移動自組網的接入協議和路由協議能夠在同一個模板上實現,本文在仿真平臺opnet設計了ieee802 . 11框架下的移動自組網節點模型和定向天線模型等,并通過對現有協議的改進,實現了特定網絡性能的計算機仿真。

Previous research on the ad hoc network almost aim at omnidirectional antenna of all receivers and transmitters , or as a default attribution . in my thesis , firstly i describe the advantages of the directional antenna at many aspects which including spatial division multiple access ( sdma ) , the antenna gain , anti - interference etc . and analyze the possibility about the directional antenna used for the ad hoc networks , secondly i study its multiple access and routine protocols using the directional antenna . and compare the protocol difference and network “ performance between omnidirectional and directional antenna in particular environment 首先闡述了定向天線在網絡空分復用( sdma ) 、天線增益、抗干擾等方面的的優勢,分析了定向天線用于移動自組網的可行性,接著重點研究了基于定向天線的多址接入協議和路由協議,分析了與全向天線在組網和協議實現中的異同點和優缺點,并對特定的環境下的網絡性能作了對比。

The directional routing protocol ds _ dsr put forward by the author is the improvement of the current protocol dsr , complete routine discovery and maintenance by directional neighbor nodes routing table , source routing and directional steering . the research discovers the application of the directional antenna , compare the omnidirectional antenna can increases the networks “ total throughput , obviously reduces the co _ channel interference ( cci ) , multiple access interference ( mai ) , enlarges the nodes “ signal and interference to noise ratio ( sinr ) , and because of the high gain of directional antenna can realize the communication with farther distance and less jump , end to end delay can decrease deeply , simultaneously , security of networks can be improved partially , the node energy also can be saved easily by power control 本文提出的定向路由協議ds _ dsr是基于對現有協議dsr的改進下實現的,通過定向鄰節點路由表、定向源路由和定向搜索來完成路由發現與維護。研究發現,定向天線的應用,相比全向天線可明顯提高網絡的總的吞吐量,減少信道干擾、多址干擾,提高信干噪比,且由于定向天線的高增益可實現較遠距離、較少跳數的通信,減少了路由發現時間,這樣大大減小了傳輸時延,網絡的整體性能得到了不同程度的提高,同時部分地解決安全問題,通過功率控制還可較容易的實現節能的目的。

In actual fact , a suitably modified amateur radio transmitter operating in either the 420 to 450 megahertz band or the 1 . 3 gigahertz band , with a highly directional antenna , is capable of transmitting voice to skull signals at less cost than the price of an automobile 事實上,一個適當限制在420到450兆赫波段或1 . 3千兆赫波段的帶有高度定向天線的業余無線電廣播發射機,能夠把聲音信號傳給頭骨并且所花的費用比一輛汽車的價格還要少。

In addition , based on the second order hilbert curve , some modifications have been done . with different kinds of substrates , the pattern - reconfigurable antennas and the broadband directional antennas are designed 第四部分,針對hilbert二階分形曲線并做一定的改進,利用不同的介質材料,設計出方向圖可重構平面天線以及寬帶的定向天線,完成了部分原理性實驗。

In the interception and direction - finding system , the phase center of the antenna is very important to the direction - finding , however , the phase center of directional antenna is few studied in the home and overseas 在偵測合一系統中,天線系統的相位中心對于系統測向有著至關重要的作用,但是目前國內外對于定向天線的相位中心研究的非常少。

The paper makes a review on the recent advance in this material , with a focus on the applications of the metamaterial in the military use , such as the radar image , directional antenna and absorbing 詳細的回顧了這種新型人工電磁材料背景、研究進展,并著重介紹了這種材料在微波頻段雷達成像,定向天線,隱形等軍事領域的應用前景。

It also proves that the algorithm is equivalent to the existing algorithm when the antennas of the base stations are omni - directional antennas by mathematical analysis 數學分析方法證明?該算法和過去僅適用于全向天線的算法在全向天線情況下的等效性以及和這種算法分貝表示形式的等價性。

Mattias lampe , ronghong jin , junping geng , min ding : invention patent “ one kind of directional / omni - directional antenna with rf switching control circuit ” , ( submitted ) 金榮洪,耿軍平,周旭竹:實用新型專利“可實現極化兼容的小型全向天線” (已提交) 。

This paper is worked to solve the phase center of the directional antenna , accordingly to giving some references for the interception and direction - finding system 本文是為了解決定向天線的相位中心問題,為偵測合一系統設計提供參考而展開研究的。

This paper presented a new method which is usable when the base stations ' antennas are directional or omni - directional antennas by using a new objective function 摘要采用新的目標函數提出能夠同時適用于定向天線和全向天線的場強定位算法。

Mattias lampe , ronghong jin , junping geng , xianguang guo : invention patent “ one kind of directional / omni - directional antenna ” ( submitted ) 丁敏,金榮洪,楊熹,耿軍平,勞佳,吳琦:發明專利“甚高頻超寬帶天線設計” (已提交) 。

Real geek types have been known to cruise around silicon valley with a laptop and directional antenna , trying to pick up networks 真正的電腦怪杰帶著便攜式電腦和定向天線在硅谷附近游蕩,試圖接入網絡。

A radio receiver and directional antenna used as a system to determine the angular direction of incoming radio signals 無線方向探測器一種無線電接收和指向天線系統,用來確定收到的無線電信號的角方向

Applying an active vibration control method for the reduction of the lateral vibration of directional antenna is investigated 摘要本文提出以電流回授主動振動控制方式,抑制指向性天線之側向振動。

Directional antennae allows the dsas to reduce background and wind noise without the need for a bulky parabolic dish 定向天線,讓員,以減少背景與風噪聲,而不需要為笨重,拋碟。

Most of the former ad hoc network mac protocols were designed for omni - directional antenna systems 以前關于adhoc網絡mac層的協議都是針對全向天線所設計的。

In radiocommunications , the radiation in a lobe of a directional antenna 在無線通信技術中,定向天線以某一波瓣輻射的電磁能。

Broadside directional antenna 垂射天線