雙軸與三軸波束切換效能5GHz新式巴特勒矩陣波束形成器

Abstract

波束切換式天線系統屬於智慧型天線之一，其基本結構包含陣列天線與波束形成器兩部分，其原理是利用產生數個不同方向之窄波束，分別指向各個方向，也就是相當於用N個天線來覆蓋N個角區域，藉此種機制可以實現追蹤用戶的目的。 論文中，分別提出具有雙軸與三軸波束切換效能，操作在5GHz的巴特勒矩陣波束形成器。雙軸波束形成器設計上，我們選擇以一組4x4巴特勒矩陣的形式，結構上使用了雙層版的方式實現，並且利用射頻切換器切換兩組雙軸方向天線，簡單電路的改良，可使得天線端的旁瓣準位達到-10dB以下。在三軸波束形成器方面，我們使用兩組8x8巴特勒矩陣，以16x16巴特勒矩陣的形式呈現，藉由巴特勒矩陣線路佈局，利用四組不同的陣列天線來達到三軸波束切換的效果。

The switched-beam antenna is one type of the smart antennas, which consists of the antenna array and the beamforming network. Its principle makes use of narrow wave of producing several different directions, pointing to each direction respectively. It is also equal to use N antennas overlay N corn district and can carry out a purpose of tracking the customer by this kind of mechanism. In this thesis, we propose novel 5-GHz Butler matrix beamformers with two-axis and three-axis beam-switching capability. In the design of 5-GHz Butler matrix beamformer with two-axis, we use two-layer structure to design one set of 4x4 Butler matrix , and implement Butler matrix beamformer with four switch-control circuits to achieve the two-axis beam-switching capability. Besides, by using simple circuits, the SSL (side-lobe level) of each beam is less than -10dB. In the 5-GHz Butler matrix beamformer with three-axis , we use two sets of 8x8 Butler matrix to present structure in the form of 16x16 Butler matrix , by setting up layout of Butler matrix , making use of four sets of antenna array to achieve three-axis beam-switching capability.