手持式數位電視天線之微小化設計

Abstract

寬頻、小尺寸、天線場型及增益都是設計天線時重要的考量因子。然而這些因子彼此之間可能會相互衝突，所以設計時必須適當的折衝與取捨。本論文設計兩個可以應用於手持式數位電視天線，分別應用蝴蝶結單極天線結構與冪次函數曲線結構製做天線，前者藉由將接地面圍繞天線提出半蝴蝶結的天線架構達到微小化及寬頻，後者應用冪次函數曲線增加前者頻寬以滿足手持式數位電視的規範。量測結果，該天線的操作頻帶涵蓋470 MHz至800 MHz。該天線為平面結構減低製作上的困難，且該天線面積小於文獻中其他設計於手持式數位電視頻段的體積。 輻射場型經由數值模擬顯示，皆具有近似單指向的(Omni-directional)輻射場型，且具有合理之天線增益，分別介於2.2 dBi至3.5 dBi之間

Broadband, size reduction, radiation pattern, and antenna gain are the major issues to be considered. It is well-known that these issues are trade-offs one another. In the thesis, by applying half-bow-tie monopole antenna and x to the power of N curved line structure, two antenna prototypes for DVB-H are proposed. With the help of ground plane surrounding the antenna, a half-bow-tie monopole antenna is proposed to increase the bandwidth. To broaden bandwidth, boundaries of No.1 antenna are changed and become a curved line. The curved line is described by a x to the power of N. The simulated and measured results confirmed that the proposed antenna can operates at 470 MHz to 800 MHz bands. The antenna not only has a simple planar structure but also yields the smallest antenna area. Moreover, the antenna has a nearly omni-directional radiation pattern and a reasonable peak gain of 2.25 dBi to 3.74 dBi.