應用於GPS／WLAN之縮小化共平面天線設計

Applied to GPS/WLAN miniaturized coplanar antenna design

本論文介紹一種應用GPS-1.57GHz和WLAN-2.4GHz之共平面波導（Co-Planar Waveguide, CPW）饋入天線（Antenna）的應用設計，而天線基板材質為使用0.8mm 的FR-4玻璃纖維基板，其介電係數是εr=4.4。本文天線主要的特性是利用設計在斜對角線的簡單對稱L型結構來產生圓極化（Circular Polarization , CP）的特性，並可使用在GPS-1.57 GHz的頻帶；另外在1.57 GHz之電流路徑上，分別在四個邊角做成一圓弧路徑，來增加電流路徑長，進而達成天線的縮小化；而饋入線的長度來達成WLAN-2.4 GHz線性極化的特性，最後以模擬和實作來探討和比較，分別得到在10 dB以下的反射損失之阻抗頻寬是1.57 GHz為508 MHz (30.9%)和2.4 GHz為750 MHz (31.25%)，而3 dB軸比頻寬在1.57 GHz是62 MHz (3.95%)，其輻射場形的極化為右手圓極化（RHCP），增益分別為 1.72 dBic和3.84 dBi，而達成本文的設計應用目標。

This paper describes an application of GPS-1.57GHz and WLAN-2.4 GHz of Co-Planar Waveguide fed antenna design. The antenna substrate material is used for 0.8 mm FR-4 glass fiber substrate, a dielectric constant of εr =4.4. The main character of this paper is the use of an antenna design in a simple slant diagonally symmetrical L-shaped structure to produce circular polarization characteristics. And it can be used in GPS-1.57 GHz frequency band. Also in the 1.57 GHz of the current path, made a circular path at four corners to increase the length of the current path, and then reached the miniaturization of the antenna. The length of the feed line is to achieve WLAN-2.4 GHz linear polarization characteristic. Finally, it is based on simulation and implementation for comparison and discussion. Respectively at 10 dB below the impedance bandwidth of the return loss is 1.57 GHz to 508 MHz (30.9%) and 2.4 GHz to 750 MHz (31.25%). The 3 dB bandwidth of the axial ratio at 1.57 GHz is 62 MHz (3.95%). Its radiation pattern of polarization is right-hand circular polarization (RHCP). Gains were 1.72 dBic and 3.84 dBi. To achieve the purpose of this paper is through research and design.