| 摘要: | 本研究論文所探討的設計是應用在手持行動通訊設備之4G LTE多頻段天線，LTE多頻段之天線設計理念是由單極天線的基礎理論加以改良。首先，調整單極天線之幾何圖形，並在天線共振路徑上以晶片電容與晶片電感取代耦合式饋入所需之電容值及天線共振路徑所需之電感值，此作法主要目的是為了縮小天線整體之面積。在設計低頻 (LTE 700/GSM 850/GSM 900) 時，發現單極天線所產生的單一共振頻率點無法達到目標所需的阻抗頻寬，欲使低頻的阻抗頻寬增加，則於單極天線路徑加上一段接地的Ground Strip，並在此Ground Strip路徑上放置晶片電感，以達到天線在低頻所需之電感值，使單極天線與接地端產生接地路徑，這樣能使低頻產生雙重共振及改善阻抗頻寬。而設計高頻 (GSM 1800/GSM 1900/UMTS 2100/ LTE 2300/LTE 2500) 時，則是利用在高頻主要路徑上增加一迴圈路徑以及一彎曲分支路徑並在天線主要路徑前段做阻抗匹配之挖槽，藉以調整天線匹配並達到此應用高達1 GHz頻寬的需求。
本研究論文設計之LTE天線產生操作頻率在0.73 GHz、0.91 GHz、2.03 GHz、2.25 GHz及2.66 GHz等五個共振頻率點。此五個共振頻率點能夠於-6 dB頻寬涵蓋 LTE 700 (698~787 MHz)、GSM 850 (824~894 MHz)、GSM 900 (880~960 MHz)、GSM 1800 (1.71~1.88 GHz)、GSM 1900 (1.85~1.99 GHz)、UMTS 2100 (1.92~2.17 GHz)、LTE 2300 (2.3~2.4 GHz)、LTE 2500 (2.5~2.69 GHz)等八個頻段。本研究論文提出之LTE天線設計於厚度為1 mm之FR4電路基板上，天線尺寸為24 x 16 x 1 mm3。而詳細的天線設計模擬分析以及量測結果將在本文中逐一介紹。;This thesis mainly discusses the designs of 4G LTE multi-band antenna for the applications of the smart mobile devices. The idea of LTE multi-band antenna design is improved by the basic theory of monopole antenna. First, by adjusting the geometry of the monopole antenna, replacing the effect of the coupling feed by the chip capacitors, and replacing the antenna resonance path by the chip inductors, the overall area of the antenna is reduced. When designing the lower frequency (LTE 700 / GSM 850 / GSM 900), it is found that the generation of the single resonant frequency of the monopole antenna is not sufficient to achieve the desired system specification. When designing the higher frequency (GSM 1800/GSM 1900/UMTS 2100/ LTE 2300/LTE 2500), by adding a loop and a bending branch on the main resonance path of the higher frequency, the required 1 GHz bandwidth is achieved.
In this thesis, the LTE antenna operates at five frequencies of 0.73 GHz, 0.91 GHz, 2.03 GHz, 2.25 GHz, and 2.66 GHz, which covering LTE 700 (698~787 MHz), GSM 850 (824~894 MHz), GSM 900 (880~960 MHz), GSM 1800 (1.71~1.88 GHz), GSM 1900 (1.85~1.99 GHz), UMTS 2100 (1.92~2.17 GHz), LTE 2300 (2.3~2.4 GHz), and LTE 2500 (2.5~2.69 GHz) with sufficient -6 dB bandwidths. The LTE antenna is designed on the FR4 circuit board with thickness of 1 mm, and area of the antenna is 24 x 16 x 1 mm3. Detailed antenna designs and experimental results are presented in the thesis. |
