2.4 GHz與60 GHz封裝天線之設計與分析

Abstract

本論文分別設計了應用於2.4 GHz與60 GHz的封裝天線，2.4 GHz部分，我們分別設計了環形封裝天線、開槽式平面倒F形封裝天線與四分之波長開槽封裝天線，由於封裝天線體積甚小，導致輻射效率不到3%，因此提出了激發載板自振的概念來大幅提升輻射效率，由於環形封裝天線與開槽式平面倒F形封裝天線上的電流分佈與載板本身半波長電偶極共振模態一致，故能有效激發載板自振並輻射。相反地，四分之波長開槽封裝天線的電流分佈與電偶極共振模態不一致，所以無法激發載板自振。 60 GHz的部分，我們先以傳統的網格陣列天線來設計封裝天線，並提出中心饋入的方式以使主波束方向不易隨頻率偏移，接著，以網格陣列天線為基礎，我們提出共平面波導饋入之新型開槽陣列天線，並分別設計了中心饋入式與邊緣饋入式的版本，後者具有較高的孔徑效率；低頻(8 GHz)驗證顯示：其峰值增益分別為12.6 dBi和13.5 dBi，阻抗頻寬皆約16%，且其峰值增益頻寬與+Z方向上增益頻寬皆達20%。最後，我們據此設計60 GHz開槽陣列天線於封裝基板上，並探討由於封裝基板過厚的厚度與過大的面積如何影響天線效能。

In this thesis, we design on-package antennas for 2.4-GHz and 60-GHz wireless communication applications, respectively. In the part of 2.4-GHz on-package antennas, three types of on-package antennas, including a loop, a slotted PIFA and a quarter-wavelength slot design, are proposed. In the absence of the carrier board, the radiation efficiencies of these antennas are lower than 3% because the sizes of on-package antennas are electrically small. Hence we exploit the self-resonance of carrier board to dramatically improve the radiation efficiency. The on-package loop antenna and slotted PIFA can induce the self-resonance of the carrier board and the carrier board become a dipole-like radiator but the on-package slot antenna cannot excite the resonance of the carrier board. The coupling mechanism to excite the self-resonance of the carrier board is discussed based on the current distributions and such concept is a feasible solution to enhance the radiation performance of other on-package antennas. In the part of 60-GHz on-package antennas, we firstly use grid array to design on-package antennas. In order to mitigate the tilted main beam, we design a central-fed grid array antenna instead of the edge-fed one. Based on the grid array antenna, we propose a novel slot array fed by a coplanar waveguide and the central- and edge-fed designs are also investigated. The edge-fed slot array antenna can achieve higher aperture efficiency. The verifications in 8 GHz reveal that the peak gains of central- and edge-fed slot array are 12.6 dBi and 13.5 dBi, respectively. The impedance bandwidths are both about 16% and the bandwidths of peak and broadside gain are both 20%. Finally, we design the newly 60-GHz slot array antennas using on-package substrate and also discuss the antenna performance effected by thick and large area of on-package substrate.